Venus, the second planet from the Sun – The Deceptive Planet. Often known as the “morning star” and “evening star” due to its bright display at sunrise and sunset throughout the year, it’s hard not to be in awe of its beauty, especially when aweing at the incredible images of its gleaming atmosphere. However, looks can be decieving, and the surface of Venus displays a most hellish landscape with searing temperatures of 900 F (475 C) and an atmospheric pressure more than 90 times that of Earth. These temperatures are even hotter than the planet Mercury, which is closer to the Sun. These extreme conditions are attributed to a “runaway greenhouse effect”, with its thick clouds trapping the solar radiation that comes from the Sun. But how did Venus become like this, and could it have been much different in the past? With its beautiful thick clouds, it was believed that Venus was a lush paradise full of oceans and life much like Earth, but spacecraft observations have revealed Venus for what it really is today, an inhospitable world incapable of supporting life as we know it. Physical Characteristics and Geology Despite its hellish landscape, Venus is often called Earth’s twin due to its similar size and density. As noted, its surface temperature and pressure are in stark contrast to our own, along with its toxic atmosphere that is inhospitable to life as we know it. Venus axial rotation also takes longer than it orbits the Sun, as one day on Venus is equal to 243 Earth days, while it takes 225 Earth days to orbit our Sun, making it the only planet in the solar system whose rotation period is longer than its orbital period. Along with its long rotation period, Venus also rotates backwards, having the Sun rise in the west and set in the east. This is similar to Uranus, although Uranus rotates on its side. The surface of Venus is currently hypothesized to be very young—geologically speaking—with estimates as young as 180 million years old. Ancient Astronomers Like most planetary objects, Venus has a rich mythology throughout human history, having long been an object of fascination for several cultures worldwide, to include Mesopotamia, ancient Greece and Rome, Christianity, and Islam, just to name a few. Due to Venus frequently disappearing due to its proximity to the Sun, the Mesopotamians believed Venus to be two entities instead of one. In Christianity, astronomical theories for dating the Star of Bethlehem often cite a possible conjunction between Jupiter and Venus as an explanation for this historic observation. Like the Mesopotamians, the ancient Egyptians believed Venus was two different bodies, as well, calling them Tioumoutiri, the morning star, and Ouaiti, the evening star. The current name Venus was eventually given by the ancient Romans after their sacred goddess, which eventually became the scientific name of the planet. Past Missions to Venus There has been a total of 43 missions launched to Venus, either for direct study or for spacecraft gravity assist en route to another planet, with a total of 26 performing successful science at the planet and another four deemed as partially or mostly successful. For context, this is a higher success rate than spacecraft missions to Mars. The first successful mission to Venus was NASA’s Mariner 2, which also became the first successful mission to another planet and conducted a flyby of Venus on December 14, 1962. Mariner 2 made successful measurements of the surface temperature and pressure at 300 -400 F and 20 times greater than on Earth, respectively, although these are much lower measurements than what future spacecrafts would observe. The former Soviet Union is the only nation to have successfully landed on the surface of Venus, sending back the first photos black and white and eventual first color images of the surface. Due to the extreme surface temperatures and pressures, some landers such as Venera 9 and 10 were only able to transmit data back to Earth for 53 and 65 minutes, while Venera 13 lasted 127 minutes on the surface. Former Paradise? Despite its current—and extreme—characteristics, the debate still rages about its past and whether or not it was once habitable like Earth, to include once having oceans like Earth. However, a 2021 study in Nature used three-dimensional global climate model simulations to suggest quite the opposite. In spite of this, and despite the extreme surface conditions, could life exist elsewhere on the planet? Life in the Clouds While the surface of Venus is a hellish and inhospitable landscape, the atmosphere has long been known to possess much milder, earthlike conditions in both temperature and pressure. In 2019, scientists hypothesized the possibility for potential biomarkers within the atmosphere of Venus. This study was based on much darker patches visible from spacecraft images, also known as “unknown absorbers”, and were hypothesized to be soaking up most of the ultraviolet and some visible light from the Sun, affecting Venus’ overall albedo (brightness) and climate. A later 2020 study in Science Advances proposed that Venus could be volcanically active today based changes in olivine at on spacecraft images and laboratory experiments. Active volcanism is one reason why life exists on Earth and could be the reason it might exist in the clouds of Venus. Future Missions to Venus With the recent studies regarding the potential for life in the atmosphere of Venus, three new missions have been approved to study the second planet from our Sun, two from NASA and one from the European Space Agency (ESA). The two NASA missions are DAVINCI+ and VERITAS, which will study the atmosphere and surface to determine past and present habitability, and DAVINCI+ will have a descent sphere that will literally plunge through the atmosphere and take the most precise measurements of this aspect of Venus. The ESA mission will be EnVision, and will be tasked to study the full planet from its deep inner core to the upper atmosphere. These missions hope to answer the longstanding questions of whether Venus was indeed habitable in the past, and more importantly, how it became the hellscape we see today. What secrets does this mysterious world hide beneath its beautiful clouds? Was it always the hellscape as we see today, or was it once a lush paradise as previously hypothesized? Future missions will explore these possibilities, and this is why we science! As always, keep doing science & keep looking up! Sources: Space.com (1), NASA Solar System Exploration (1), Space.com (2), Smithsonian Magazine, Wikipedia (1), Understanding Planets in Ancient Mesopotamia, Space.com (3), NBC News, Wikipedia (2), NASA JPL, NASA (1), Smithsonian National Air and Space Museum, European Space Agency (1), NASA Solar System Exploration (2), NASA Solar System Exploration (3), NASA (2), Nature, AIP Proceedings, EarthSky, Science Advances, NASA (3), Space.com (4), European Space Agency (2)

Could we identify an alien terraformed planet through the detection of greenhouse gases? This is what a recent study published in The Astrophysical Journal hopes to address as a team of international researchers investigated whether artificial greenhouse gases could be detected from an exoplanet whose alien inhabitants could be attempting to terraform that world, either from trying to control its climate or terraforming an uninhabitable planet into a habitable one. This study holds the potential to help scientists better understand the criteria and methods for identifying an extraterrestrial civilization, especially with the number of confirmed exoplanets increasing almost weekly. “For us, these gases are bad because we don’t want to increase warming” said Dr. Edward Schwieterman, who is an Assistant Professor of Astrobiology at the University of California Riverside and lead author of the study. “But they’d be good for a civilization that perhaps wanted to forestall an impending ice age or terraform an otherwise-uninhabitable planet in their system, as humans have proposed for Mars.” Artist's illustration of an exoplanet undergoing the terraforming process from a snowball planet to a habitable planet. (Credit: Thibaut Roger/University of Bern) For the study, the researchers calculated the time for NASA’s James Webb Space Telescope (JWST) to detect greenhouse gases on TRAPPIST-1 f, which is located approximately 41 light-years from Earth and is one of seven confirmed Earth-sized exoplanets, with TRAPPIST-1 f being hypothesized as a snowball planet due to its distance from its host star, though a 2023 study postulated it could contain an interior liquid water ocean. Additionally, the team also examined the potential for future telescopes to detect greenhouse gases, including the Large Interferometer for Exoplanets mission concept. In the end, the team found that JWST could detect various levels of greenhouse gases after imaging between 5 and 25 transits of TRAPPIST-1 f while noting that more powerful space telescopes in the future could detect greenhouse gases easier, as well. “Our thought experiment shows how powerful our next-generation telescopes will be. We are the first generation in history that has the technology to systematically look for life and intelligence in our galactic neighborhood,” said Dr. Daniel Angerhausen, who is an Astrophysicist and Astrobiologist at ETH Zurich and a co-author on the study. Will scientists be able to detect artificial greenhouse gases from an exoplanet in the coming years and decades? Only time will tell, and this is why we science! As always, keep doing science & keep looking up! Sources: The Astrophysical Journal, EurekAlert!, UC Riverside News, NASA

How do astronauts cope with life onboard the International Space Station (ISS) and how can scientists study it? This is what a recent study published in PLoS ONE hopes to address as an international team of researchers used archaeological investigation strategies to ascertain how ISS crew members managed their lives in space, specifically pertaining to the astronauts’ habits of using and storing the various materials onboard the orbiting outpost. This study holds the potential to help scientists better understand how humans cope with living in space for long periods of time, which could be useful for trips to the Moon and Mars, someday. The study, known as the Sampling Quadrangle Assemblages Research Experiment (SQuARE) experiment, was conducted over a 60-day period between January and March 2022 where six common locations onboard the ISS were designated as “squares”, which is a common archaeology strategy of digging pits to ascertain the most viable areas of further investigation. During the study, the astronauts photographed each square every day to ascertain how they were used, and the researchers would compare that to the location’s original purpose. Image of one of the "squares" used in the study which shows various items being stored next to a crew berth (right of the square). (Credit: Walsh et al., 2024, PLOS ONE, CC-BY 4.0) In the end, the researchers found that two of the squares located at a maintenance area and the latrine, respectively, the researchers observed a total of 5,438 items throughout the 60-day study period among these two squares, noting a large discrepancy between how the locations were used compared to their designed use, specifically with them being used as personal storage spaces or hygiene. “The experiment is the first archaeology ever to happen off of the planet Earth,” the authors note. “By applying a very traditional method for sampling a site to a completely new kind of archaeological context, we show how the ISS crew uses different areas of the space station in ways that diverge from designs and mission plans. Architects and planners of future space stations can learn valuable lessons from this work.” This study comes as the ISS is slated to be “retired” in 2030, although NASA continues to contemplate this action depending on the development of commercial space stations before then. What new discoveries will researchers make about astronaut habits in space in the coming years and decades? Only time will tell, and this is why we science! As always, keep doing science & keep looking up! Sources: PLoS One, EurekAlert!

In a recent study published in Nanoscale, a team of researchers led by the University of Pittsburgh have designed new materials for direct air capture (DAC) technologies that improve upon previous designs for capturing carbon dioxide (CO2) from the air. This study has the potential to improve the amount of carbon dioxide that is captured, as capturing large quantities of CO2 has proven to be a difficult task. This is due to CO2 competing with water in terms of being captured, and the result is often that large quantities of CO2 go free. "If materials are good at grabbing carbon dioxide, they're usually good at grabbing multiple gasses," explained Dr. Katherine Hornbostel, who is an assistant professor of mechanical engineering and materials science at the University of Pittsburgh Swanson School of Engineering, and a co-author on the study. "It's really hard to tune these materials to grab carbon dioxide but nothing else, and that's what this research is focused on." The study involved improving on what are known as metal-organic frameworks (MOFs), which the paper refers to as “frequently proposed as candidate materials to selectively adsorb CO2 for carbon capture processes.” The purpose of this study is to consider a novel core-shell MOF design strategy meant to capture higher quantities of CO2. "If you're trying to work with an adhesive, it can be hard to come up with something that's sticky to one material that's not also sticky to the other material, and that's true all the way down to the molecular scale," said Dr. Christopher E. Wilmer, who is an associate professor of chemical and petroleum engineering and William Kepler Whiteford Faculty Fellow in the Swanson School, and a co-author on the study. "So, when we make a material that's very sticky to carbon dioxide, inadvertently, it's usually also sticky to water. We're trying to find a way to shield those sticky surfaces from water." While DAC is primarily used to reverse climate change effects, the researchers have a long-term goal for DAC beyond Earth, as well. "When we're on other planets, like Mars, direct air capture is how we get fuel to return to Earth," Wilmer said. "Every technology we design pushes the ball forward." Sources: Nanoscale As always, keep doing science & keep looking up!

How can astronomers determine if an exoplanet has water based on Earth’s geological composition? This is what a recent study published in Nature Astronomy hopes to address as a team of researchers led by Cornell University are developing a new catalog for identifying past or present water on exoplanets by examining Earth processes and using NASA’s powerful James Webb Space Telescope (JWST) to search for these signatures on exoplanets throughout the cosmos. This study holds the potential to help researchers develop more sophisticated methods in finding water on exoplanets, which could help scientists identify signs of life beyond Earth, as well. For the study, the researchers analyzed 15 samples of basalt to better understand their mineralogical compositions, formation processes, and spectral signatures. Basalt is a volcanic rock that forms from rapid cooling of lava and is the most common type of rock found in Earth’s crust, along with being prevalent on other planetary bodies, including the Moon and Mars. Since most of the Earth’s ocean floors are made of basalt, this provides a unique opportunity for researchers to better understand how water might form in the presence of basalt. “When the Martian mantle melted, it also produced basalts. The moon is mostly basaltic,” said Dr. Esteban Gazel, who is a Charles N. Mellowes Professor in Engineering at Cornell University and a co-author on the study. “We’re testing basaltic materials here on Earth to eventually elucidate the composition of exoplanets through the James Webb Space Telescope data.” Once the initial analyses were conducted, the researchers then aspired to learn whether JWST’s powerful instruments could detect these spectral signatures on exoplanets with the goal of identifying similar minerals on those worlds. In the end, the researchers determined that JWST’s mid-infrared instrument could potentially identify these same minerals, and specifically water-bearing minerals, on exoplanets throughout the cosmos. The goal is to eventually determine the environmental conditions that the rocks formed, thus gaining greater insight into their water content, which the researchers hope to ascertain with a new catalog they’re developing regarding water-world exoplanets. How will this new catalog help astronomers identify water-world exoplanets in the coming years and decades? Only time will tell, and this is why we science! As always, keep doing science & keep looking up! Sources: Nature Astronomy, ScienceDaily, Cornell Chronicle

Does food smell and taste different to astronauts in space and what steps can be taken to mitigate this in the future? This is what a recent study published in the International Journal of Food Science & Technology as an international team of researchers investigated how food aromas could be altered to amplify food taste. This study holds the potential to help researchers improve diets for isolated individuals, specifically in space or nursing home residents. For the study, the researchers analyzed food odor perception of vanilla, almond, and lemon among 54 participants between 18 to 39 years old in a neutral setting and a virtual reality (VR) simulation of the International Space Station (ISS) with a key trait being they had no history of vertigo or motion sickness. The participants were asked to rate the potency of the aromas in both settings to compare any differences between the two environments. Image of study co-author, Dr. Gail Iles from RMIT University, smelling an aroma sample while wearing a VR headset. (Credit: Seamus Daniel, RMIT University) In the end, the participants reported notably greater potencies for almond and vanilla odors in the ISS VR simulation compared to the neutral environment, along with participants who reported reduced sensitivity to all odors noted greater potency for almond, as well. “One of the long-term aims of the research is to make better tailored foods for astronauts, as well as other people who are in isolated environments, to increase their nutritional intake closer to 100%,” said Dr. Julia Low, who is a senior lecturer at RMIT University in Australia and a co-author on the study. Dr. Low noted how the ISS VR simulations changed the spatial perception of the participants, which she hypothesized played a role in their changed odor perception. This could mean that weightlessness experienced by astronauts, specifically pertaining to fluid shifts in the body, could cause the same difference in odor perceptions compared to being on Earth. The goal is to develop diet plans for future astronauts on long-term missions that provide the essential nutrients they need while in space. “What we’re going to see in the future with the Artemis missions are much longer missions, years in length, particularly when we go to Mars, so we really need to understand the problems with diet and food and how crew interact with their food,” said Dr. Gail Iles, who is an associate professor at RMIT University and a co-author on the study. What new discoveries about food odors, diet, and space travel will researchers make in the coming years and decades? Only time will tell, and this is why we science! As always, keep doing science & keep looking up! Sources: International Journal of Food Science & Technology, EurekAlert!

Fans of the show The Expanse will undoubtedly know about Ceres Station, with its six million inhabitants, artificial gravity, extensive tube train network, and the hundreds of ships docked there on any given day. While this might be the case a few hundred years from now, today the dwarf planet Ceres is a large spherical rock orbiting in the asteroid belt with a semi-major axis (average distance) of 257 million miles (414 million kilometers) from the Sun. Being the largest object in the asteroid belt, it’s no coincidence that Ceres was the first asteroid belt object to be discovered when Giuseppe Piazzi spotted it in 1801. Ceres is named for the Roman goddess of corn and harvests, and the word “cereal” comes from the same name. Ceres is classified as a dwarf planet, having this designation since 2006. While it comprises 25% of the total mass of the asteroid belt, the dwarf planet Pluto is still 14 times more massive. As noted, Ceres is a dwarf planet like Pluto, and it received this designation in 2006 by the International Astronomical Union, which also resulted in the demotion of Pluto from full-fledged planet to dwarf planet. Ceres was studied extensively by the Dawn spacecraft from 2015 to 2018, becoming the first spacecraft to orbit a dwarf planet. During its mission, Dawn discovered that Ceres possibly formed much farther from the Sun than where the dwarf planet currently resides today. The spacecraft found ammonia on the surface of Ceres, which requires much colder temperatures—beyond the orbit of Jupiter—to condense. Ceres is mostly known for its mysterious bright spots imaged by the Dawn spacecraft as it approached the dwarf planet in 2015. Scientists now believe these bright spots are salt deposits leftover from brine, or salt-enriched water, emanating from Ceres’ interior. With no atmosphere, this salt-enriched liquid exposed to space would immediately evaporate, leaving behind a kind of salt crust on the surface. While this might indicate a liquid ocean within Ceres, some experts remain unconvinced. While the Dawn mission ended in 2018, a proposed mission called the Ceres Polar Lander would send an orbiter-lander combo to Ceres, dropping the lander at its north pole to search for clues about life. The mission would use the same kind of soft-landing techniques NASA has used to land spacecraft on Mars. As always, keep doing science & keep looking up! Sources: The Expanse Wiki, Dictionary.com, NASA Solar System Exploration (1), NASA JPL, Britannica, NASA Solar System Exploration (2), EarthSky, Scientific American, NASA, Space.com

According to Forbes.com, a company called Space Tango, co-founded by Kris Kimel, is interested in how hemp grows in low-space orbit. So yes, there soon will be “weed”, at least in seed form, sent into space (and only hemp seeds at that). Space Tango, a spin-off from the University of Kentucky, has dedicated lab space on the International Space Station (ISS) (called TangoLab). They use TangoLab to research various subjects in low-orbit space, such as life and physical sciences, flow chemistry, biomedical, and materials manufacturing. They have sent plants to the International Space Station to test how agricultural crops fair in a “stress-free” environment. Source: UnSplash.com On Earth, various stressors can have impacts on what proteins are expressed in plants. These are similar to defense mechanisms. For example, in cannabis, according to Dr. Joe Chapelle, a member of Space Tango's Science Advisory Team, the biggest stress that they want to eliminate on the ISS is gravity. Dr. Chapelle explains, “When plants are ‘stressed,’ they pull from a genetic reservoir to produce compounds that allow them to adapt and survive.” One of those compounds just happens to be one of the more popular compounds found in dispensaries and vape stores around the country: cannabidiol (CBD). CBD is known, down here on Earth, to be a non-psychoactive compound found in cannabis that can be used to relieve a number of ailments, from anxiety, inflammation, chronic pain, to many other physiological disorders. The purpose of taking plants into space is, as Dr. Chapelle explains, to form an “[u]nderstanding [of] how plants react in an environment where the traditional stress of gravity is removed [which could] provide new insights...[on] how researchers might take advantage of...[the] discovery of new characteristics, traits, biomedical applications, and efficacy,”. Source: UnSplash.com Space Tango is playing it safe though, and it is only sending up hemp seeds. Hemp, which has very little THC (<0.03%), is a very useful crop for textiles and other materials, as this newsletter has described before. It has also recently been made legal on the federal level due to the passage of the latest Farm Bill. In considering future trips to Mars and beyond, it is essential to find crops that could be cultivated in new environments. Hemp is a tough little plant, which could be used over cotton for textiles and even over metal in some cases (hemp-based cars anyone?). The ISS is no stranger to testing crops in low orbit. It has its own laboratory for doing just this, called the Vegetable Production System ("Veggie" for short). However, Space Tango has its own module, the TangoLab-1, which was installed on the ISS in 2016 (there is now a TangoLab-2). Space Tango has teamed up with Atalo Holdings, who will provide certified hemp seed and expertise, and Anavii Market, a source for hemp-derived CBD therapeutics. The mission is slated for February 2019. Here is a video describing how the University of Kentucky (UK) has worked with Space Tango and the ISS to conduct their research. Video Source: YouTube.com Sources: Forbes.com, SpaceTango.com, Neurotherapeutics, Future Medicinal Chemistry, Pain Physician, LabRoots.com, CNBC News - YouTube Channel, techport.nasa.gov, AtaloHoldings.com, AnaviiMarket.com

How does extra salty water, also known as briny water, form and evolve on worlds without atmospheres, such as asteroids and moons? This is what a recent study published in The Planetary Science Journal hopes to address as a team of researchers investigated how briny water could still flow for a period of time on the asteroid Vesta after large impacts resulted in the melting of subsurface ice. This study holds the potential to help researchers better understand the geological and chemical processes on planetary bodies without atmospheres and what this could mean for finding life as we know it. “We wanted to investigate our previously proposed idea that ice underneath the surface of an airless world could be excavated and melted by an impact and then flow along the walls of the impact crater to form distinct surface features,” said Dr. Jennifer Scully, who is a planetary geologist at NASA’s Jet Propulsion Laboratory (JPL) and a co-author on the study. For the study, the researchers used a JPL test chamber to analyze how liquid samples responded to rapid drops in atmospheric pressure on the asteroid Vesta, thus simulating the conditions of a high-speed impact, which also includes the very brief creation of an atmosphere resulting from that impact. In the end, the researchers made some intriguing findings that could help scientists better understand the geological and chemical processes that occur on planetary bodies without atmospheres. Cornelia Crater on Vesta displaying sloped deposits (right) and curvilinear gullies (white arrows, left). (Credit: Jet Propulsion Laboratory) “Through our simulated impacts, we found that the pure water froze too quickly in a vacuum to effect meaningful change, but salt and water mixtures, or brines, stayed liquid and flowing for a minimum of one hour,” said Dr. Michael J. Poston, who is a research scientist at the Southwest Research Institute in Texas and lead author of the study. “This is sufficient for the brine to destabilize slopes on crater walls on rocky bodies, cause erosion and landslides, and potentially form other unique geological features found on icy moons.” While the team focused on just Vesta, these simulations could also apply to other airless bodies, including Europa, Ceres, and even Mars with its atmosphere that is a fraction of the Earth’s. Additionally, these results could help scientists better understand certain surface features on these worlds, including the smooth plains and “spider” features observed within Manannán crater on Europa, along with Martian crater gullies. What new discoveries will researchers make about briny water and airless worlds in the coming years and decades? Only time will tell, and this is why we science! As always, keep doing science & keep looking up! Sources: The Planetary Science Journal, NASA, EurekAlert!, Southwest Research Institute, NASA (1), NASA (2), NASA JPL, Wikipedia

How close are Earth-sized exoplanets to Earth? This is what a recent study published in Astronomy & Astrophysics hopes to address as a large international team of researchers have announced the discovery of Barnard b, which orbits Barnard’s star approximately 6 light-years from Earth. This discovery is profound because Barnard’s star is the closest single star to Earth but also because Barnard b is estimated to be approximately just over one-third the mass of the Earth, or approximately three times the mass of the planet Mars. Barnard’s star is approximately 16 percent the mass of our Sun with approximately 19 percent of its diameter. While the size of Barnard b poses the possibility that it might be Earth-like, its 3.15-day orbit puts it well inside its star’s habitable zone (HZ). “Barnard b is one of the lowest-mass exoplanets known and one of the few known with a mass less than that of Earth. But the planet is too close to the host star, closer than the habitable zone,” said Dr. Jonay González Hernández, who is a researcher at the Instituto de Astrofísica de Canarias in Spain, and lead author of the study. “Even if the star is about 2500 degrees cooler than our Sun, it is too hot there to maintain liquid water on the surface.” This discovery was made using a multitude of instruments from the European Southern Observatory (ESO), including ESPRESSO (Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations), HARPS (High Accuracy Radial velocity Planet Searcher), HARPS-N (High Accuracy Radial velocity Planet Searcher for the Northern hemisphere), and CARMENES (Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Echelle Spectrographs). In addition to Barnard b, astronomers also identified three other exoplanet candidates with estimated orbital periods of 2.34 days, 4.12 days, and 6.74 days. “We now need to continue observing this star to confirm the other candidate signals,” said Dr. Alejandro Suárez Mascareño, who is a researcher also at the Instituto de Astrofísica de Canarias and a co-author on the study. “But the discovery of this planet, along with other previous discoveries such as Proxima b and d, shows that our cosmic backyard is full of low-mass planets.” What new discoveries about exoplanets around Barnards’s star will researchers make in the coming years and decades? Only time will tell, and this is why we science! As always, keep doing science & keep looking up! Sources: Astronomy & Astrophysics, Wikipedia, EurekAlert!, European Southern Observatory Featured Image: Artist's impression of Barnard b. (Credit: ESO/M. Kornmesser)

What can asteroids teach us about the early solar system and were they responsible for bringing water to the Earth in its early history? This is what a recent study published in Icarus hopes to address as a team of international researchers investigated a specific family of asteroids known as Erigone asteroids, which orbit in the main asteroid belt between Mars and Jupiter, as part of the PRIMitive Asteroid Spectroscopic Survey (PRIMASS) project to help further constrain the processes that created our solar system billions of years ago, along with trying to determine if asteroids were responsible for bringing water to Earth, as well. This study holds the potential for researchers to establish new methods of analyzing asteroids, with the scientific community hypothesizing that asteroids hold the key to better understanding our solar system’s history. “There are theories that the Earth could have received a fraction of its water from primitive asteroids in the early Solar System,” said Brittany Harvison, who is a PhD student at the University of Central Florida along with being a researcher at the Florida Space Institute (FSI), and lead author of the study. “A big portion of these theories is understanding how these primitive asteroids were transported into Earth’s path. So, exploring primitive asteroids in the Solar System today could help paint a picture of what was going on all those years ago.” For the study, the researchers analyzed 25 asteroids of the Erigone family using archived infrared telescope data, with the reason Erigone asteroids are of interest is due to their high-water content, with Polana asteroids being known for their low-water content. The intent of the PRIMASS project is to learn more about collisional family of asteroids, or asteroids that are hypothesized to have once been part of a larger asteroid but were broken up due to a massive (or several massive) collision. Along with high-water content, Erigone asteroids also had yet to be studied for entry into the PRIMASS database, which made this study even more intriguing. In the end, the researchers found that primitive asteroids within the inner solar system demonstrated varying levels of water content compared to Erigone and Polana asteroids, which challenges longstanding hypotheses as to where these primitive asteroids belong in terms of asteroid classification. The team aspires to broaden this research scope with the goal of ascertaining if asteroids were indeed responsible for brining water to Earth billions of years ago. “There’s this fascination when I’m looking at this data and I’m examining something that’s millions of miles away,” said Harvison. “We can look back billions of years and learn the initial structure and composition of the early solar system by studying the surface of these asteroids. That’s always been something that excites me.” What new discoveries will researchers make about primitive asteroids in the solar system in the coming years and decades? Only time will tell, and this is why we science! As always, keep doing science & keep looking up! Sources: Icarus, Planetary Science Institute, EurekAlert!, UCF Today Featured Image: Artist’s illustration displaying how certain asteroid families, including Erigone, are created. (Credit: NASA/JPL-Caltech)

Our Moon has long been hypothesized to have formed from a planet-sized object colliding with the Earth. But, what happened after and how can its unique geologic exterior and interior be explained? This is what a recent study published in Nature Geoscience hopes to address as an international team of researchers led by the Lunar and Planetary Laboratory (LPL) at the University of Arizona used a combination of spacecraft data and computer models to investigate the geologic processes that led to heavier elements being present on the nearside of the Moon, which is constantly facing Earth due to being tidally locked with our planet. This study holds the potential to help researchers better understand the geologic mechanisms behind planetary formation and could lead to gaining greater insight into how rocky planets like Earth and Mars formed. For the study, the researchers used data from NASA’s GRAIL mission, which was used to map gravitational anomalies on the Moon, and computer models to determine the distribution of ilmenite, a combination of titanium and iron, across the Moon’s nearside and how much sunk into the Moon’s interior during the Moon’s formation and evolution. It has been previously hypothesized that while ilmenite sunk to the Moon’s interior early on, portions of it returned to the surface from volcanism, and the mechanisms behind these events have led scientists puzzled. Cutaway illustration displaying a gravity gradient map (blue hexagonal pattern) produced by the GRAIL spacecraft of the Moon’s nearside with two ilmenite-bearing downwellings demonstrating how ilmenite both sunk into the interior then returned to the surface over time. (Credit: Adrien Broquet/University of Arizona & Audrey Lasbordes) In the end, the researchers discovered a positive correlation between the computer models and GRAIL data, indicating the Moon’s gravity field can be used to determine the locations of the leftover ilmenite that either didn’t sink to the interior or resurfaced during volcanic events. Additionally, the team estimated the ilmenite sank to the interior approximately 4.22 billion years ago, followed by portions of it resurfacing during volcanic activity later. "For the first time we have physical evidence showing us what was happening in the moon’s interior during this critical stage in its evolution, and that's really exciting," said Dr. Jeff Andrews-Hanna, who is an LPL associate professor and a co-author on the study. "It turns out that the moon’s earliest history is written below the surface, and it just took the right combination of models and data to unveil that story." What new discoveries about the Moon’s formation and evolution will researchers make in the coming years and decades? Only time will tell, and this is why we science! As always, keep doing science & keep looking up! Sources: Nature Geoscience, NASA, EurekAlert!

This year was one of the most exciting ones for all of the space geeks around the world. Many discoveries and once in a lifetime events happened in astronomy. Read on to learn about the most memorable space events of 2019. January In January, NASA’s New Horizons pictures of Ultima Thule fascinated the science world. The image of the small cosmic object encouraged so many discussions in social media and it brought many associations. The Kuiper Belt object began to be known as the ‘snowman’ because of its structure of two different objects joint into one whole. Ultima Thule gave scientists an opportunity to sneak into the Solar System’s most distant areas, beyond the orbit of Pluto. More data, collected by New Horizons' mission, awaits to be received so we can be sure that the image of Ultima Thule was just the beginning. February In February, NASA announced one of its future missions whose aim will be to study the most distant places of the Universe, gaining knowledge about the post-Big Bang cosmic evolution, and to hunt for the presence of water and organic molecules in our galaxy. The launch of SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer) is planned for 2023 and its duration is estimated to be two years. SPHEREx will study around 300 million galaxies. The key objective of the mission will remain to focus on extremely distant star clusters. March In March, a possible mission to visit Titan – one of the moons of Saturn, was announced. Dragonfly is expected to be launched in 2026 and to reach Titan around 2034. The structure of the space probe is planned to resemble a drone. Titan is one of the places in our Solar System with the highest chances to sustain life. The Saturnine moon is bigger than the closest planet to our Sun-Mercury and it is the second biggest moon in our Solar System. The atmosphere of Titan is mainly composed of nitrogen and there are rains of methane. The temperature on its surface is much lower than Earth’s because of the great distance from the Sun. Dragonfly will be part of the series of missions of NASA, known as New Frontiers. New Horizons, Juno and OSIRIS-REx also form part of New Frontiers. April April was probably the most exciting month of the whole year in the science world and that is quite reasonable. In April, we saw the first-ever direct image of a black hole. Why this was so important? Until now, black holes were something that we knew existed but we have never had real proof of this idea. We could tell that black holes were real and possible to form, judging by Einstein’s equations and by the discoveries of a whole movement of scientists who followed his ideas and developed them in a completely new field of space studies. The first-ever picture of a black hole was made by using several radio telescopes around the globe, which worked as one whole. The pictured black hole is a supermassive black hole, located in the center of the M87 galaxy, 55 million light-years away from us. Its mass is also fascinating – 6.5 billion times the mass of the Sun. May After the euphoria experienced in April, May seemed quite boring in terms of scientific discoveries. At the end of the month, recent research suggested the existence of an insulated underground ocean on Pluto – once thought to be the ninth planet, then transferred to the rank of a ‘dwarf planet’. As Pluto is located too far from the Sun, its destiny is marked as an icy object, but scientists believe that oceans are hiding under its icy crust. Despite the fact that Pluto’s ocean is probably not made of water but other liquids scientists still aim to study its structure and understand if life can develop without the presence of water. June The scientific world was still overwhelmed by the first image of a black hole, as it will be for a long time. However, science does not have a day-off and it does not stop discovering and searching for the answers to hundreds of questions. In June, we had an exciting discovery of a new type of quasars. Quasars are the most luminous objects in the whole Universe, ejecting 10 trillion times more energy than the Sun. Studying the nature of the quasars gives many answers about the behavior of the supermassive black holes, which are located in the centers of the galaxies. The group of scientists who discovered the blue quasars believe that they are strongly associated with the merging of galaxies. Our galaxy – the Milky Way is expected to begin its merging with its closest neighbor – the Andromeda galaxy in 3 to 4 billion years. July July was marked by the 50th anniversary of the Apollo 11 mission. Scientists prefer looking into the future instead of remembering the past. However, remembering all those who took the risk for future generations is always worth it. Two of the astronauts of Apollo 11 are still alive so we have the amazing opportunity to hear what was to be the first in such a dangerous challenge. Probably the most emotional part of the Apollo 11 celebrations was one of Buzz Aldrin’s speeches when he expressed his disappointment with the fact that 50 years later the field has not experienced any progress. August In August, the scientific editions told us the story of a planet, called HR 5183 b, which amazed scientists with its weird egg-shaped orbit. HR 5183 b has a mass three times bigger than that of Jupiter (the biggest planet in our Solar System). There is no other exoplanet with such eccentricity in the orbit around its host star. HR 5183 b can go as far as the orbit of Neptune away from its star and then come closer at a distance similar to this between our Sun and the asteroid belt, located between Mars and Jupiter. Scientists explain the eccentric orbit of the exoplanet with a possible collision between it and other objects in the past, likely a companion planet of the same size. September We will probably remember September with India’s unsuccessful mission to the Moon. We will also remember how the discovery of water molecules on an exoplanet became so viral that it went into the TV news around the globe. K2-18b is an exoplanet, located at a distance of 110 light-years away from Earth. Scientists found traces of water vapor on the planet but they cannot say how much exactly it is – it could be either 0.1% or 50%. With current technologies, we are still not capable of finding out. K2-18b may have some water in its atmosphere, but there are other important characteristics, which are not so attractive. For example, its size is two times bigger than the size of the Earth and its mass is eight times greater, which means that gravity is stronger, so walking could be extremely hard. If there is even a solid surface. October In October we learned about an explosion that happened somewhere near the supermassive black hole in the center of the Milky Way 3.5 million years ago. The explosion sent a cone-shaped burst of radiation through both poles of the galaxy and out into deep space. The explosion was so powerful that scientists cannot come up with another proposal for its source. They agree that it should have been provoked by the activity of the supermassive black hole Sagittarius A* which lies in the center of our galaxy. This discovery is so important because it changed our minds about the activity of Sagittarius A* which we thought was quite low. November November came with good news for all astronomy geeks around the world. It was confirmed that Voyager 2 has reached interstellar space. This makes Voyager 2 the second manmade object to go beyond the outer boundaries of our Solar System after Voyager 1 did that back in 2012. Scientists confirmed the news after noticing changes in the data of cosmic plasma density, which the space probe sent back to the Earth. Voyager 2 reached interstellar space at a distance of 119.7 AU (approximately 17 billion km) from the Sun. December is here and we cannot wait to see what discoveries lie ahead. Sources: Cosmos Magazine, NASA

What physiological effects can extended periods of microgravity have on the human eye? This is what a recent study published in npj Microgravity hopes to address as a team of researchers investigated how the shifting of fluids under microgravity conditions could lead to eye vessel alterations. This study holds the potential to help space agencies, researchers, and the public better understand the short- and long-term physiological effects of microgravity, specifically with more humans traveling beyond Earth’s gravity on commercial spaceflights. “When we experience microgravity conditions, we see changes in the cardiovascular system because gravity is not pulling down all these fluids as it typically does on Earth when we are in an upright position,” said Dr. Ana Diaz Artiles, who is an assistant professor in the Department of Aerospace Engineering at Texas A&M University and a co-author on the study. “When we're upright, a large part of our fluids are stored in our legs, but in microgravity we get a redistribution of fluids into the upper body.” For the study, the researchers analyzed how lower body negative pressure (LBNP), which involves the transferring of fluids from the upper body to the lower body, could potentially be used to counteract what’s known as Spaceflight Associated Neuro-ocular Syndrome (SANS), which, while still not well understood, often results in physiological changes in the eyes, also called ocular prefusion pressure (OPP). Using 24 participants, 12 male and 12 female, the researchers subjected the participants to treatments inside an LBNP chamber to ascertain the effects on counteracting OPP. In the end, the researchers found LBNP was ineffective in reducing OPP while noting that LBNP could be used to counteract SANS should increased OPP be linked to SANS. However, the researchers also note further research is required to better understand the connection between OPP and SANS. “This research is just one experiment of a three-part study to better understand the effects of fluid shift in the body and its relationship to SANS. Previous experiments in this study included the use of a tilt table for researchers to understand the cardiovascular effects of fluid shifts at different altered gravity levels, recreated by using different tilt angles,” said Dr. Diaz Artiles. Since the dawn of human space flight, the study of microgravity on the human body has been at the forefront of understanding both the short- and long-term impacts of space travel. The International Space Station (ISS) has been instrumental in conducting countless research experiments during its 20-plus years of service regarding the physiological effects of space travel, most notably on astronauts spending more than a year onboard the ISS. However, with humans returning to the Moon in the next few years and on to Mars within the next decade, scientists remain steadfast in their efforts to better understand extended durations in microgravity if humans are to venture further into the cosmos. What new discoveries will researchers make about the physiological effects of microgravity in the coming years and decades? Only time will tell, and this is why we science! As always, keep doing science & keep looking up! Sources: npj Microgravity, EurekAlert!, Texas A&M University Engineering Featured Image: NASA astronaut, Andrew Morgan, seen during one of his missions to the International Space Station taking images of his retina while using the Chibis device, which was designed to counteract bodily fluid changes duirng microgravity. (Credit: NASA)

Jupiter’s moon, Europa, is one of the most fascinating planetary bodies in our solar system as it’s one of the few places where we believe life might currently exist beyond Earth. It’s known as an icy moon, as its surface is almost entirely covered in water ice, but it’s the supposed saltwater ocean that swirls beneath its icy crust that has scientists abuzz as to what kinds of life we might find within its watery depths. While the much-anticipated NASA Europa Clipper mission isn’t scheduled to launch until 2024, scientists are currently forced to study Europa’s surface until we can get a better glimpse of what might lie beneath the icy outer shell. In a recent study published in The Planetary Science Journal, a Southwest Research Institute-led (SwRI) team used the Hubble Space Telescope to observe Jupiter's moon, Europa, at ultraviolet (UV) wavelengths, filling in a "gap" in the various wavelengths used to observe this icy water world. The team's near-global UV maps show concentrations of sulfur dioxide on Europa's trailing side, or hemisphere. Like Earth's Moon, Europa is tidally-locked with Jupiter, and the trailing hemisphere is the side of the moon that always faces away from the satellite's orbital direction. Studying Europa's surface material can give insights into the potential composition of the subsurface ocean that is hypthsized to be swirling beneath its icy outer shell. What's compelling about this study is the dataset from SwRI is the first to produce a near-global map of sulfur dioxide that correlates with large-scale darker regions in both the visible and the ultraviolet wavelengths. "The results were not surprising, but we did get much better coverage and resolution than previous observations," said SwRI's Dr. Philippa Molyneux, a co-author of the paper. "Most of the sulfur dioxide is seen on the 'trailing' hemisphere of Europa. It's likely concentrated there because Jupiter's co-rotating magnetic field traps sulfur particles spewing from Io's volcanoes and slams them against the backside of Europa." Another active moon of Jupiter is Io, which is considered the most volcanic body in the solar system and essentially a big ball of sulfur. Jupiter's immense magnetic field can cause chemical reactions between Europa's water ice and Io's sulfur eruptions, ultimately creating the sulfur dioxide on the surface of Europa's trailing hemisphere. "In addition to studying the sulfur dioxide on the surface, we are continuing to try to understand the puzzle of why Europa -- which has a surface that is known to be dominated by water ice -- does not look like water ice at ultraviolet wavelengths, as confirmed by this paper," Becker said. "We are actively working to understand why." Along with Europa, other planetary bodies of astrobiology interest include Mars; Saturn’s moons, Titan and Enceladus; and Neptune’s moon, Triton, due to its active geysers. What further secrets will we uncover about Europa and its icy characteristics? Only time will tell, and this is why we science! As always, keep doing science & keep looking up! Sources: NASA JPL, The Planetary Science Journal

A team of scientists has used data obtained from a suborbital rocket used in the NASA Endurance mission a to reveal an electric field that is as widespread and likely as essential to the planet as the magnetic and gravitational fields. This phenomenon, an ambipolar electric field that was first hypothesized to exist about 60 years ago, allows the atmosphere surrounding the planet to escape over the North and South poles. The strength of the field and its influence on a part of the atmopshere known as the ionosphere was estimated from measurements obtained by the rocket. The findings, which help explain atmospheric escape, were reported in Nature. A steady stream of particles flowing from our atmosphere and into space has been detectable by spacecraft and accompanying equipment since the late 1960s. The outflow, which has been called the 'polar wind,' had been predicted by researchers. This study can help researchers understand various characteristics of the atmosphere, such as its movement, evolution, and polar winds. The work can also help us determine whether there are other planets that are friendly to life, and what extraterrestrial atmospheres may be like. Intense sunlight would be expected to enable particles to escape from Earth's atmosphere. But polar wind observations are more intense than what would be predicted by sunlight alone. Many particles in the polar wind were also found to be cold, and show no signs of heating, even while moving at supersonic speeds. “Something had to be drawing these particles out of the atmosphere,” said first study author Glyn Collinson, principal investigator of Endurance at NASA’s Goddard Space Flight Center. The electric field that was expected was also thought to be very weak, and only able to exert effects over hundreds of miles. The Endurance mission shot a rocket into the atmosphere in 2022, which collected data over a range of 322 miles; it crashed into the Greenland Sea under a half hour later. It measured a change in electric potential that was only 0.55 volts, which is about as powerful as a watch battery, noted Collinson. It's not much. “But that’s just the right amount to explain the polar wind.” Hydrogen ions are the most common particle in the polar wind, and they are subjected to forces from the electric field that are 10.6 times stronger than gravity. “That’s more than enough to counter gravity; in fact, it’s enough to launch them upwards into space at supersonic speeds,” said study co-author Alex Glocer, Endurance project scientist at NASA Goddard. Oxygen ions are heavier, but are also boosted by the electric field. The data indicated that our ionosphere stay denser at greater heights than they would be without the field. “It’s like this conveyor belt, lifting the atmosphere up into space,” Collinson added. The researchers noted that other electric fields like this probably exist on other planets, even some in our solar system like Venus and Mars. “Any planet with an atmosphere should have an ambipolar field,” Collinson explained. “Now that we’ve finally measured it, we can begin learning how it’s shaped our planet as well as others over time.” Sources: NASA, Nature

This series will explore historic space missions from the start of the Space Age to the present day, including both crewed and robotic missions. Here we will investigate the scientific rationale behind each mission and, most importantly, what we learned from these early missions and how they helped shape future missions that will launch to the Moon and Mars within the coming years. Previously, we looked at NASA’s Ranger Program, which helped the lauded space agency determine landing sites for the upcoming Apollo missions, along with giving scientists a better understanding of the Moon and its geologic makeup. While failures were encountered with the first few missions, these mistakes only allowed us to develop more successful missions, resulting in data that is being used to this day. With our scientific knowledge of the Moon vastly improved, NASA approved the Surveyor Program, which lasted from 1966 to 1968 with the goal of landing on the Moon’s surface, as the Ranger missions were designed strictly to crash into a pre-determined location. Without knowing if a Moon landing was possible, this raised concerns over the ultimate success of Apollo. The primary goal of the Surveyor program was to demonstrate soft landings at several locations on the Moon, which could then be applied to landing humans on the surface. Unlike the Ranger program, which was besieged with failures from the outset, the Surveyor program started off highly successful, ultimately landing five of the seven missions on the Moon, with Surveyor 2 and 4 ending in failure due to an engine failure and loss of signal, respectively. The first mission was Surveyor 1, which was a complete success, becoming the first soft landing of a United States spacecraft on the surface of the Moon, with the Soviet Union’s Luna 9 lander becoming the first overall. Surveyor 1 returned panoramic images of its landing site within a 62-mile (100-kilometer) diameter crater containing boulders greater than 3 feet (1 meter) scattered around the landscape. Despite the enormous success of Surveyor 1, the Surveyor 2 mission crashed into the Moon after one of its thrusters failed to fire while en route to the Moon, putting the spacecraft into a spin and crashed just southeast of Copernicus Crater. The Surveyor 3 mission was the first to have a surface-sampling instrument that allowed scientists to the conclude the lunar regolith contained composition like wet sand. While the spacecraft bounced upon landing due to the main engine failing to cut off at the correct time, the lander sent back 6,326 images of its surrounding area. What’s unique about this mission is the Apollo 12 astronauts went to the landing site, bringing back pieces of the lander to Earth. Once again, despite the enormous success of the previous mission, Surveyor 4 ended in failure when radio signals from the spacecraft ceased only a few minutes prior to touchdown, with NASA being unsuccessful in re-establishing contact. The final three Surveyor missions were resounding successes. Surveyor 5 became the first spacecraft to conduct an analysis of the lunar regolith while returning over 20,000 images of its surroundings over its three-day mission. It also made the extraordinary discovery that the surface of the Moon was comprised of basalt, henceforth making it conducive to human exploration. Surveyor 6 became the first spacecraft to launch from the lunar surface as it demonstrated a “hop” maneuver to see if rockets could be fired so close to the surface. The lander ultimately sent back close to 30,000 images of the lunar surface. Much like Ranger 9, which was designed to meet scientific objectives since its predecessors succeeded in gathering enough data for the Apollo landings, Surveyor 7 was also designed strictly for scientific purposes for the same reason. It was the first of the Surveyor missions to land in the lunar highlands (mountains) and carried with it the largest suite of science instruments, to include an alpha-scattering instrument designed to perform chemical analyses of the lunar surface. This included analyses of undisturbed lunar regolith, a Moon rock, and a small area dug up by the surface sampler. Overall, the Surveyor program was a resounding success and not only helped pave the way for the Apollo landings, but also continued to give us new insights into the Moon and its composition. As Artemis 1 prepares to lift off on its maiden flight, it’s important to look back and marvel in the scientific and engineering feats the Surveyor missions achieved, which ultimately helped shaped the upcoming Artemis missions. Sources: Labroots, USRA, NASA, NASA (2), NASA JPL, NASA (3), NASA (4), NASA (5), NASA (6), NASA (7), CNN As always, keep doing science & keep looking up!

Temple Grandin: Innovator and Advocate It was the only place where she felt calmer, and she had created it for herself. Temple Grandin was in high school when she designed and built the “squeeze machine,” or “hug box.” The device was intended to alleviate anxiety by way of deep pressure, which reduces sensory stimuli. For someone like Grandin, such a machine made the often-overwhelming sensory stimulation of daily life bearable. She had sought out the sort of whole-body deep pressure she’d first seen at work years earlier on her aunt and uncle’s ranch. Whenever a cow needed to be restrained – immunization, for example — it was put into a squeeze chute, where continuous, whole-body pressure reduced — albeit inadvertently — the terrible fear and anxiety felt by cattle in unnatural environments. It was this realization that led Grandin to create her own hug box to reduce her own anxiousness. Despite the fact that Temple couldn’t stand being held by another human being, she knew the box would work. Temple Grandin understood animals because she has the condition known as autism. On the high functioning end of the spectrum — remarkably so, in fact — Grandin was in her forties when she started theorizing in earnest about why she could understand things about animals that other, “neurotypical” people couldn’t. She’d already been working with animals for many years at that point. Long before she trained as an animal scientist, Grandin had been around horses, cattle, and other livestock. She’d seen the way they behaved, but never connected their experience with her own. Then again, she had no other experience but her own, and didn’t fully comprehend that she was unusual. Instead, throughout her young life she’d endured the taunts of classmates. “Tape Recorder,” they said mockingly because of her tendency to repeat herself. “Retard,” they spat at her. But she didn’t go down without a fight. She hauled off and smacked them. Sure, Temple was different from most other kids, but she was nobody’s fool – and she she wasn’t going to put up with nonsense. Animals were like that, too, and they accepted her just as she was. Maybe because they shared a strong affinity for each other’s minds. It was no more than two years after she was born in 1947 that Temple was diagnosed with autism. At the time, this condition was considered the result of brain damage, and young Temple was not initially given the sort of education that would help her develop her capacities to their fullest. Unwilling to let her daughter effectively rot away, Eustacia Cutler followed one doctor’s advice and hired a speech therapist and set to work developing Temple’s cognitive capacities. Not only did Grandin learn to speak, but she also went to college and graduate school, earning a B.A. degree in Psychology, and an M.A. and Ph.D. in Animal Science. Since 1990, Temple has been an Animal Sciences professor at Colorado State University, where she combined her two passions: animals and autism advocacy. Animals had saved her from emotional isolation when she was a schoolgirl, where the taunts and bullying had further isolated her. It was the gentle horses at her school that gave her a safe haven. She wanted to return the favor. A longtime advocate of humane treatment of animals, Temple’s work has largely centered on how animal suffering during the stockyard and slaughtering experience can be alleviated. To that end she has worked as a livestock handling facilities designer, and consulted for large corporations, such as McDonald’s, Burger King, and Wendy’s. For Temple, understanding animals’ suffering means understanding their minds. An animal is a sensory-based thinker. In other words, they think in pictures and sounds and smells. For example, as Temple herself points out, a fire hydrant is a huge information center for a dog. They can tell who’s been there, when, whether or not it was a friend or enemy — things you and I would not be able to glean for sniffing the hydrant! Similarly, a flag waving at the top of a pole at a vet center on a livestock handling facility is going to make cattle balk. The most sensible thing to do is take the flag down and put it somewhere else. But how did Gandin come know that this is how animals think? Because, she says, this is how she thinks. “I think in pictures, I don’t think in language,” she says. If someone unlike her thinks of a steeple, she explains, that person typically pictures in a generic way, but Temple sees specific pictures — this steeple from her childhood or that steeple she saw the other day. They come up one at a time, but she sees them successively, and can form a sort of movie. She calls this feature of her mind photo realistic visual thinking. This same sort of mind has trouble with reading and algebra — dyslexics fall into this category of mind. Cattle balk at rapid movement and contrast. Grandin got into the cattle chute to see what they were seeing. Her picture thinking was an essential asset to her livestock handling facilities designs, which improves how cattle are treated during the stages of the slaughtering process. Other types of minds are pattern thinkers. These, Grandin says, are thinkers good at engineering, programming, and music. Still another mind is the verbal mind, the one that knows all sorts of facts. “The normal brain ignores the details,” she says. The autistic brain, regardless of what type of mind it is, is immersed in detail. This sort of careful thinking about the nature and function of her own mind and the minds of others has long been part of what makes Grandin uniquely qualified to advocate on behalf of preserving neurodiversity. She’s managed, through the combination of her own experience, intellect, education, and facility with language to become a sought-after public speaker on autism. Since the mid-1980s, she has been giving talks on autism across the country while maintaining her career as an animal scientist. Her ability to clearly describe to others what it feels like to be hypersensitive to noise, to be unable to bear certain physical contact, and to feel the rage and pain of being taunted and tormented by ignorant children has allowed others to begin understanding that difference is not the mark of inferiority. Perhaps Grandin’s singular accomplishment is having overcome stigmas associated with autism by embracingit. In so doing, she has become a uniquely qualified advocate not only for autism, neurodiversity, and educating diverse minds, but also for animal rights. For someone diagnosed with autism, the level of empathy exhibited by her activism is extraordinary. It’s extraordinary not because, as an autistic, she doesn’t have feelings, but because society has, for decades, misunderstood the condition. Though Temple has said that she is not particularly interested in feelings that neurotypical individuals take for granted, there can be little doubt that she has a deep understanding of the frantic and directionless nature of anxiety. To articulate so clearly a lived experience that resists coherent accounts makes Grandin even more extraordinary than her already extraordinary story is. That’s because she has found a way to connect with others in a profoundly meaningful way. Now almost 75-years old, Temple Grandin has not merely adjusted to a life that can feel unbearable at times, she has reshaped it both for herself, for other autistics, for those of us who cannot possibly experience life as she knows it, and for non-human animals. We have all benefitted from Temple’s extraordinary accomplishments, her drive to come to terms with who she is and to celebrate it. In recent years, Grandin has increased her advocacy of the idea that autism is not something to be cured, that there is value in diverse types of minds. Her interest not just in her own mind, but the minds of others, has prompted her to champion the diversity of various thinking types. In fact, she understands that this diversity is essential to civilization’s progress. Temple Grandin’s mind — Temple Grandin herself — is a living testament to what can be accomplished when you live your most authentic life. So, what type of mind are you and what is your most authentic life? Sources: Author Interview with Temple Grandin, Grandin.com, TempleGrandin.com, Biography.com, Ted Talks, Colorado State University Additional Citations: Grandin, Temple, and Johnson, Catherine, Animals are Not Things: Creating The Best Life for Animals. Mariner Books, 2014. Grandin, Temple, and Johnson, Catherine, Animals in Translation: Using the Mysteries of Autism to Decode Animal Behavior. Scribner, 2006. Grandin, Temple, The Autistc Brain: Helping Different Kinds of Minds Succeed. Mariner Books, 2014. Grandin, Temple, The Way I See It: A Personal Look at Autism and Asperger’s, 2nd Ed. Future Horizons, 2011. Sacks, Oliver, An Anthropologist on Mars. Knopf, 1995.

Volcanoes are one of nature’s most awe-inspiring creations, giant mountains ejecting red hot lava that are both beautiful and deadly. We recently explored why volcanoes are so astounding, but, did you know that Earth isn’t the only place where volcanism occurs? In fact, there are more than a few worlds within our own solar system that exhibit evidence of either past or present volcanic activity. Some of these worlds even exhibit a phenomenon called cryovolcanism; meaning that instead of projecting hot magma, these volcanoes eject frozen particles or ice. Here, we will explore the different types of volcanism, the off-Earth worlds that experience this incredible feature, and the forces that create them both on Earth and elsewhere in our galaxy. Volcanism as we know it here on Earth is the process by which molten rock, pyroclastic fragments, or hot water and steam are discharged from distinct geological settings including volcanoes, geysers, and fumaroles. On Earth, internal heat drives plate tectonics and the subducting—or sliding—of plates beneath one another which occurs at various plate boundaries across the Earth and drives volcanism. Photo of eruption at Mount Redoubt in Alaska in 2009. (Credit: Game McGimsey, USGS) “Volcanism is one of the manifestations of how planets lose heat from their interiors, and as such is one of the four primary geologic processes (the others being impact cratering, tectonism, and gradation (weathering, erosion, and deposition of sediment)),” said Dr. David Williams, a Research Professor in the School of Earth and Space Exploration at Arizona State University. Dr. Williams points out the importance of studying volcanism not just here on Earth, he told Labroots that, “all rocky planetary objects larger than about 600km in diameter that have been visited by spacecraft show some evidence of volcanic activity in their histories and, as such, studying volcanism is key to understanding planetary evolution.” The first extraterrestrial volcanic eruption was observed on Jupiter’s innermost Galilean moon, Io, by the Voyager 1 spacecraft on March 8, 1979 as it was leaving Jupiter en route to Saturn. This instantly famous image showed two eruptions, one occurring on the limb of the moon, and the other eruption is seen at the moon’s terminator (the shadow between the day side and night side). The eruption observed at the limb was so large that it was initially mistaken as another object emerging from the other side of Io. Unlike Earth, the volcanism observed on Io is not the result of plate tectonics, but a different force known as tidal heating, which happens when an object’s gravity is so strong it’s able to bend and flex a much smaller object in an elliptical orbit around it. The elliptical orbit means Io’s distance to Jupiter changes during its orbit. When Io is closer to Jupiter, the immense gravity stretches Io, and when it’s farther away, the moon compresses back to normal. Over long periods of time, this constant flexing leads to internal friction with Io, which leads to heat and pressure, and ultimately, the intense volcanic activity we have observed on its surface. Left: This photo was taken by Voyager 1 on March 8, 1979, looking back 2.6 million miles (4.5 million kilometers) at Io, three days after its historic encounter. One eruption can be seen on the limb, (at upper left) showing ash clouds rising more than 150 miles (260 kilometers) above Io's surface. The second eruption can be seen on the terminator (shadow between day and night) where the volcanic cloud is catching the rays of the rising sun. Right: Similar style eruptions imaged by the Galileo spacecraft on June 28, 1997 from a distance of about 373,000 miles (600,000 kilometers). (Credit: NASA/JPL) Since Voyager 1’s encounter at Io, many other examples of volcanism have been observed around the solar system. These other planetary bodies exhibit cryovolcanism, which occurs in environments that experience far lower temperatures than we have here on Earth. These eruptions often involve the discharge of liquid water, sulfur dioxide, methane, and ammonia onto the surface of an icy planet or satellite. Examples of planetary bodies that are known to presently display cryovolcanism include one of Jupiter’s Galilean moons, Europa, along with Saturn’s moon, Enceladus, Neptune’s largest moon, Triton, and Pluto’s largest moon, Charon. “Cryovolcanism, or ‘cold volcanism’, refers to volcanic activity by non-silicate materials usually found on objects in the outer solar system,” said Dr. Williams. “The idea is that liquid water, when mixed with an antifreeze like salt, or substances like methane or ammonia, becomes molten or stable at temperatures colder than found on Earth. These cryovolcanic fluids can then erupt on these mostly airless icy moons in the outer solar system, producing both effusive flows and explosive ash-like deposits that have been observed on their surfaces by planetary spacecraft. As with more traditional ‘silicate’ volcanism found on the Earth, the Moon, or Mars, understanding the compositions and morphologies (shapes and forms) of cryovolcanic deposits can inform scientists about the evolution of the surfaces and interiors of icy worlds.” Like the volcanism observed on Earth and Io, cryovolcanism occurs due to the extreme buildup of pressure over long periods of time under the planet's surface. However, the forces responsible for cryovolcanism have been found to vary from world to world. As discussed, Io’s volcanism occurs from tidal heating, which is the same force that is also responsible for the cryovolcanism on Jupiter’s second innermost Galilean moon, Europa. While this icy world was first discovered by Galileo Galilei in 1610, it wasn’t studied up close until the flyby of NASA’s Pioneer 10 and 11 spacecrafts in 1973 and 1974. However, the images taken by these crafts were very low resolution. It wasn’t until 1979 when Voyager 1 and 2 visited Jupiter and took more detailed images of Europa that the crater-less surface was revealed, indicating recent geologic activity. Later, NASA’s Galileo spacecraft took some of the most detailed images of Europa to date. View of Europa taken by Voyager 1 from a range of 1.6 million miles (2,869,252 kilometers) on March 2, 1979, at 2:00pm. The color composite is made from three black and white images taken through the orange, green and violet filters. (Credit: NASA/JPL) This image from NASA's Galileo spacecraft in the late 1990s shows the stunning diversity of Europa's surface geology. A crater-less surface complimented with long, linear cracks and ridges that crisscross the surface, interrupted by regions of disrupted terrain where the surface ice crust has been broken up and re-frozen into new patterns. (Credit: NASA/JPL/SETI Institute) However, since Europa orbits beyond Io and closer than the other two Galilean moons, Ganymede and Callisto, Europa is being stretched and compressed by the gravity of these other moons. As such, the earlier spacecraft missions provided the first hints that Europa might contain an ocean of liquid water deep beneath its icy surface.However, in the case of Europa, the case for cryovolcanism is still hotly debated. “Just like on Earth with normal volcanism, cryovolcanism is driven by heat and pressure, with more emphasis on pressure,” said Dr. Jessica Noviello, a postdoctoral research scientist at NASA’s Goddard Space Flight Center. “On Europa, the current thinking is that the subsurface ocean itself is over-pressurized and pushing up against and into the ice shell. Some of the features on Europa’s surface, like the ‘mountains in a moat’, may be evidence of extrusive cryovolcanic eruptions as a result of this excess pressure.” Dr. Noviello also mentioned Saturn’s largest moon, Titan, as another world exhibiting cryovolcanic activity, specifically Doom Mons, the largest cryovolcano in the entire solar system. “Titan is also one of the few key places for astrobiological studies in the solar system, mainly because of the large amounts of liquid methane on the surface, its seasonal changes, and its thick atmosphere.” Dr. Noviello said. A natural color view from NASA's Cassini spacecraft taken on January 30, 2012, at a distance of approximately 119,000 miles (191,000 kilometers). (Credit: NASA/JPL/Space Science Institute) Titan in ultraviolet and infrared taken by NASA's Cassini spacecraft on October 26, 2004. (Credit: NASA/JPL/Space Science Institute) Another one of Saturn’s moons that also exhibits (albeit extreme) cryovolcanism is Saturn’s moon, Enceladus. While this ocean world was discovered by William Herschel in 1789, its cryovolcanism attributes went undiscovered until NASA’s Cassini spacecraft observed active geysers that erupted water and organic molecules from the south pole in 2005. “Enceladus is cryovolcanically active via its plumes in the tiger stripes region at its southern hemisphere,” said Dr. Noviello. “It’s an explosive process we are still trying to understand.” Image of Enceladus taken by NASA's Cassini spacecraft on October 9, 2008, shortly after coming within 15.6 miles (25 kilometers) of the surface. (Credit: NASA/JPL/Space Science Institute) Cassini image of geysers located at the south pole “tiger stripes” of Enceladus spraying water ice and vapor into space. (Credit: NASA/JPL/Space Science Institute) Arguably the closest example of cryovolcanism in terms of distance from Earth has been observed on the dwarf planet, Ceres, the largest planetary body in the asteroid belt. Evidence of ancient cryovolcanism was imaged by NASA’s Dawn spacecraft featuring Ahuna Mons and Occator Crater. NASA's Dawn spacecraft observed Ahuna Mons on March 14, 2018, detecting traces of sodium carbonate (red and green coloring in the bottom right image). (Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/ASI/INAF) Image of Occator Crater on Ceres by NASA's Dawn spacecraft. The bright spots are hypothesized to be a form of salt, specifically brine. (Credit: NASA / JPL-Caltech / UCLA / Max Planck Institute for Solar System Studies / German Aerospace Center / IDA / Planetary Science Institute) With all this cryovolcanic activity throughout the solar system, what does this mean in the search for life beyond Earth? Are the worlds of Europa, Enceladus, and Titan potential harbors for life as we know it? “Heat from volcanic and cryovolcanic eruptions can alter and mobilize fluids, bringing nutrients to locations that can serve as breeding grounds for microbial life,” said Dr. Williams. “Locations on planetary surfaces where volcanism occurs are often ideal places to search for evidence of primitive life.” Earth is currently the only known planet to support life, and certain requirements must be met for life as we understand it to exist elsewhere. “Heat and liquid water are two important ingredients for life, but they aren’t the only things that life needs,” said Dr. Noviello. “Evidence of cryovolcanism is good evidence of both heat and liquid water, at least at some point in a planetary body’s existence. Studying the places where heat and liquid water are is the first step in finding evidence of life in the Solar System beyond Earth, but knowing the differences between these worlds beyond the basics is what helps us as scientists contextualize what we find.” NASA is currently scheduled to launch its Europa Clipper mission to that icy world in October 2024 in hopes of learning more about its habitability. While this particular mission is only slated to be an orbiter, plans are in the works to figure out how we might use cryobots to drill through Europa’s thick icy shell and explore its watery depths to search for life. Artist's impression of a hypothetical cryobot on Europa. (Credit: NASA) Volcanism and cryovolcanism are beautiful displays of nature, both here on Earth and elsewhere in the cosmos. While traditional volcanism is often viewed as a sign of death and destruction, cryovolcanism can inversely be viewed as a sign of life and creation. In just the last few decades, we’ve learned that both volcanism and cryovolcanism are a very common phenomenon within just our own solar system. Is this the same outside of our solar system? Could we find an even more intriguing type of volcanism never before seen in our cosmos? Only time will tell. Sources: Labroots, Britannica, Arizona State University, Encyclopedia of Astrobiology, NASA JPL, Universe Today, NASA, NASA (2), NASA (3), NASA (4), NASA (5), Nature Astronomy, NASA (6), NASA (7), Stone Aerospace As always, keep doing science & keep looking up!

Introduction CAR-T therapies represent a new successful strategy for the treatment of hematological malignancies; however, recent studies have revealed some limitations, including the occurrence of graft-versus-host disease (GVHD), neurotoxicity, and cytokine release syndromes (CRS). This has prompted researchers to look for alternative, safer cells, such as natural killer (NK) cells1. NK cells are lymphocytes that kill tumor cells and virus-infected cells non-specifically, without prior sensitization. CAR-NK therapy involves the modification of NK cells with mature chimeric antigen receptor (CAR) technology to exploit their unique target cell recognition mechanism and broad tumor-killing ability. Figure 1 illustrates the CAR-NK therapeutic strategy1. Compared with CAR-T therapy, CAR-NK therapy has numerous advantages, such as lower GVHD and significantly reduced CRS toxicity and immune effector cell-associated neurotoxicity syndrome toxicity, which enhance overall safety2, 3. In addition, NK cells have multiple tumor recognition sites, thus potentially reducing antigenic escape failure4. Figure 1. The flow chart of CAR-NK therapy. CAR Molecule Design CAR has the ability to specifically recognize target cells and activate NK cells to kill tumor cells. Therefore, the design and engineering of the CAR structure are crucial for CAR-NK therapeutic success. Similar to CAR-T, CAR is composed of an extracellular antigen binding domain, a hinge domain, a transmembrane (TM) domain, and an intracellular domain2. The extracellular domain contains a single-chain variable fragment (scFv) derived from monoclonal antibodies that provides the ability to specifically recognize and bind to tumor antigens. The hinge domain connects extracellular domain to TM domain5. The intracellular signaling domain determines the strength of the activation signal and directly affects the killing effect6. Table 1 summarizes the molecules of CAR structure in CAR-NK2. Table 1. Molecules of the CAR structure in CAR-NK Currently, there are four generations of CARs, with different structures and compositions (Figure 2). First-generation CARs contain only CD3ζ or DAP12 as signaling structural domains. Second-generation CARs express a second signaling structural domain including CD28 or 4-1BB associated with CD3ζ, and third-generation CARs include CD3ζ and two co-stimulatory signaling domains (CD28 and 4-1BB). Finally, fourth-generation CARs involving NK cells can release cytokines, such as IL-2 and IL-15, which regulate NK cells proliferation. This effectively enhanced the anti-tumor activity of NK cells against lymphoma xenografts1, 7. Figure 2. The four generations of CAR structure. (doi:10.1186/s40364-022-00364-6) Source of NK Cells NK-92 cell lines have been widely used as a source of CAR-NK cells due to their remarkable proliferation ability in vitro and reduced sensitivity to repeated freeze/thaw cycles. However, as malignant cells from a NK cell lymphoma, NK92 cells have some inherent limitations including potential tumorigenicity risk, absence of CD16 and NKp44 expression, and the need for lethal irradiation prior to infusion, which hampers in vivo expansion potential. Umbilical cord blood (UCB) presents another attractive source of NK cells with various advantages, such as off-the-shelf availability, low T cell contamination risk, and great potential for proliferation and persistence in vivo. To overcome volume limitations, UCB are expanded to large numbers through a variety of methods covering cytokine mixture and artificial antigen-presenting cells. In addition, NK cells can be acquired from other sources (as shown in Figure 1), including peripheral blood (PB), cord blood (CB), peripheral blood mononuclear cells (PBMCs), and stem cells such as induced pluripotent stem cells (iPSCs)8, 9. Scientists are exploring the use of NK cells, and will find the best source for NK-cell immunotherapy for their research. Preparation and Expansion of CAR-NK Cells With advances in genetic engineering technology, several methods have been established to generate CAR-NK cells. Commonly used CAR-NK transduction systems utilize viral and non-viral vectors. Viral vectors include retroviruses, lentiviruses and adeno-associated viruses (AAV)6, with the retroviral transduction being the most common method of delivering CAR to NK cells. Non-viral vectors include the sleeping beauty and PiggyBac transposons. Additionally, mRNA electroporation and the CRISPR/Cas9 technique can also be used. There are several techniques to expand CAR-NK cells, and the two most commonly used approaches involve feeder cells and cytokine mixtures. Cytokines are important for the in vivo development and survival of NK cells. IL-21 promotes NK cell proliferation and enhances its cytotoxic function. IL-15 stimulates the expansion and cytotoxic activity of NK cells. It is also used in combination with IL-2 to expand NK cells in vitro10, 11. Sino Biological offers GMP-grade cytokines, including IL-2, IL-12, IL-15, and IL-21, and also provides comprehensive solutions for CAR-NK therapy to support cellular immunotherapy. Clinical Trials of CAR-NK As of August 2023, several clinical trials of solid and hematological tumors with CAR-NK therapies have been conducted worldwide. Currently, there are no FDA-approved drugs for CAR-NK and the vast majority are in preclinical phases, with some entering clinical phase I/II (Table 2). Recently, a CAR-NK therapy was developed to target CD19 for the treatment of B-cell lymphoblastic leukemia/lymphoma in a phase I/II study (NCT05654038). This is a single-center, open-labeled, single-arm, non-randomized investigator-initiated trial to evaluate the efficacy and safety of anti-CD19 universal CAR-NK (UCAR-NK) cells therapy combined with HSCT for the treatment of B-cell hematologic malignancies. In addition, the purpose of another clinical trial (NCT05528341) is to evaluate the safety and effects of NKG2D-CAR-NK92 infusion for the treatment of relapsed/refractory solid tumors. The clinical trials involving CAR-NK therapy have primarily focused on hematologic malignancies, including B-cell lymphoma, B-cell non-Hodgkin lymphoma (B-cell NHL), acute myeloid leukemia (AML), B-cell hematologic malignancies, acute lymphoblastic leukemia, and multiple myeloma12-14. CAR-NK therapy is also being tested against solid tumors, such as glioblastoma, breast cancer, small cell lung cancer, colorectal cancer, prostate cancer, and ovarian cancer11, 15, 16. These clinical trials have shown that CAR-NK therapies target CD19, CD7, CD22, CD33, CD70, BCMA, NKG2D, HER2, DLL3, mesothelin, ROBO1, Claudin 6, or PSMA to achieve therapeutic efficacy13, 16. Table 2. Clinical Trials involving CAR-NK cell therapy Conclusion CAR-NK cells have unique advantages over CAR-T cells, such as more precise killing, more cell sources, and greater efficacy against solid tumors. However, some challenges remain, such as cytotoxicity, low transfection efficiency, and storage issues. As CAR-NK therapies continue to be developed and refined, preclinical studies and preliminary clinical data indicate that CAR-NK therapy has improved safety. CAR-NK therapy lacks the human leukocyte antigen matching limitations, possesses a lower GVHD, CRS, and neurotoxicity, in addition to the potential of using allogeneic NK cells as a CAR platform for “off-the-shelf” therapy. Therefore, CAR-NK therapy holds great promise as a novel cancer treatment strategy with fewer side effects. References 1. Marofi F, Saleh MM, Rahman HS, et al. CAR-engineered NK cells; a promising therapeutic option for treatment of hematological malignancies. Stem Cell Res Ther. 2021;12(1):374. Published 2021 Jul 2. doi:10.1186/s13287-021-02462-y 2. Pang Z, Wang Z, Li F, Feng C, Mu X. Current Progress of CAR-NK Therapy in Cancer Treatment. Cancers (Basel). 2022; 14(17):4318. Published 2022 Sep 2. doi:10.3390/cancers14174318 3. Valeri A, García-Ortiz A, Castellano E, et al. Overcoming tumor resistance mechanisms in CAR-NK cell therapy. Front Immunol. 2022;13:953849. Published 2022 Aug 3. doi:10.3389/fimmu.2022.953849 4. Liu E, Marin D, Banerjee P, et al. Use of CAR-Transduced Natural Killer Cells in CD19-Positive Lymphoid Tumors. N Engl J Med. 2020;382(6):545-553. doi:10.1056/NEJMoa1910607 5. Fujiwara K, Tsunei A, Kusabuka H, Ogaki E, Tachibana M, Okada N. Hinge and Transmembrane Domains of Chimeric Antigen Receptor Regulate Receptor Expression and Signaling Threshold. Cells. 2020;9(5):1182. Published 2020 May 9. doi:10.3390/cells9051182) 6. Gong Y, Klein Wolterink RGJ, Wang J, Bos GMJ, Germeraad WTV. Chimeric antigen receptor natural killer (CAR-NK) cell design and engineering for cancer therapy. J Hematol Oncol. 2021;14(1):73. Published 2021 May 1. doi:10.1186/s13045-021-01083-5 7. Zhang L, Meng Y, Feng X, Han Z. CAR-NK cells for cancer immunotherapy: from bench to bedside. Biomark Res. 2022;10(1):12. Published 2022 Mar 18. doi:10.1186/s40364-022-00364-6 8. Zhao X, Cai L, Hu Y, Wang H. Cord-Blood Natural Killer Cell-Based Immunotherapy for Cancer. Front Immunol. 2020;11:584099. Published 2020 Oct 22. doi:10.3389/fimmu.2020.584099 9. Xie G, Dong H, Liang Y, Ham JD, Rizwan R, Chen J. CAR-NK cells: A promising cellular immunotherapy for cancer. EBioMedicine. 2020;59:102975. doi:10.1016/j.ebiom.2020.102975 10. Hu W, Wang G, Huang D, Sui M, Xu Y. Cancer Immunotherapy Based on Natural Killer Cells: Current Progress and New Opportunities. Front Immunol. 2019;10:1205. Published 2019 May 31. doi:10.3389/fimmu.2019.01205 11. Kilgour MK, Bastin DJ, Lee SH, Ardolino M, McComb S, Visram A. Advancements in CAR-NK therapy: lessons to be learned from CAR-T therapy. Front Immunol. 2023;14:1166038. Published 2023 May 2. doi:10.3389/fimmu.2023.1166038 12. Huang R, Wen Q, Zhang X. CAR-NK cell therapy for hematological malignancies: recent updates from ASH 2022. J Hematol Oncol. 2023;16(1):35. Published 2023 Apr 7. doi:10.1186/s13045-023-01435-3 13. Shao R, Li Z, Xin H, et al. Biomarkers as targets for CAR-T/NK cell therapy in AML. Biomark Res. 2023;11(1):65. Published 2023 Jun 17. doi:10.1186/s40364-023-00501-9 14. Tian X, Zhang R, Qin H, et al. Immunotherapy of B cell lymphoma with CD22-redirected CAR NK-92 cells. Cent Eur J Immunol. 2023;48(1):1-13. doi:10.5114/ceji.2023.126672 15. Jan CI, Huang SW, Canoll P, et al. Targeting human leukocyte antigen G with chimeric antigen receptors of natural killer cells convert immunosuppression to ablate solid tumors. J Immunother Cancer. 2021;9(10):e003050. doi:10.1136/jitc-2021-003050 16. Khawar MB, Gao G, Rafiq M, et al. Breaking down barriers: The potential of smarter CAR-engineered NK cells against solid tumors [published online ahead of print, 2023 Aug 11]. J Cell Biochem. 2023;10.1002/jcb.30460. doi:10.1002/jcb.30460

Published by Pirouz Daftarian, Ph.D. Enhanced Signal-to-Noise Ratio as a Primary Advantage of MBLI Tetramers Concerning Biological Interactions with Dextran. In this blog, we will discuss the increasing evidence in the literature and emphasize key considerations when working with MHC multimers containing dextran. Since, dextran has been used as a backbone for the generation of MHC multimers by various investigators. It is beneficial and informative to discuss the impact of nonspecific bindings and immune cell activation on cell staining, immune monitoring, T cell analysis, and downstream outcomes for investigators. Two important features will be addressed: 1) the interaction of cells of immune cell lineages with glucan, the building blocks of dextran 2) the activation of selected immune cells by glucan / dextran. Dextran is a complex branched glucan (e.g. β-glucan), or polysaccharide, that is derived from glucose. Dextran is a generic term for a family of glucans that are made by the polymerization of the α-d-glucopyranosyl moiety of sucrose. It is also of note that dextran may be of varying lengths, ranging from 3 to 2000 kilodaltons. Dextran is a type of polysaccharide commonly used in research settings for the isolation and purification of lymphocytes, including T cells. Dextran can interact with cell surface receptors, facilitating isolation through techniques like density gradient centrifugation. In fact, historically, Dextran by its interaction with lymphocytes, allows sedimentation that causes erythrocytes to sediment, while allowing neutrophils and PBMCs to remain in suspension with plasma and dextran (1,2). Moreover, dextran via its glucan has the capability to bind and activate cells of innate and adaptive immunity (1-12). The specific surface receptors that have been currently identified for β-glucan receptors are, dendritic cell-associated C-type lectin-1 (Dectin-1), complement receptor 3 (CR3), cluster of differentiation 11b (CD11b)/CD18, αMβ2-integrin, macrophage differentiation antigen-1 (Mac-1), lactosylceramide (LacCer), and scavenger receptors (SRs) (5), and CD5 (1). T cells and B-1 cells express CD5, a scavenger receptor family member that is associated with antigen receptors. A few recent studies have characterized the binding of β-glucan to CD5 on T cells and B-1 cells (1). The affinity of CD5 and β-glucan is calculated as 3.7 × 10−9 M (1). As shown in the figure, dextran, through its beta-glucan, recognizes and stimulates immune responses (2). In addition, dextran can potentially activate lymphocytes, particularly T cells, through its interaction with antigen-presenting cells (APCs) and the major histocompatibility complex (MHC) molecules (1). During immunization, dextran can be used as a carrier for antigens, where it helps enhance the immune response by promoting antigen presentation to T cells. However, the specific immunological effects of dextran can vary depending on factors such as its molecular weight, and degree of branching (13). In ex vivo settings, dextran sulfate is a trick that immunologists have been using to stimulate mononuclear cells and to elicit the “blast” condition (4). In summary, the dextran composed of β-glucans has the capacity to interact and activate both adaptive and innate immune response. This type of activation can offer therapeutic applications or present a challenge for researchers. When working with dextran’s back bone MHC multimers, there is an increased risk of false positive activation and misleading results in flow cytometry staining of antigen specific T cells. The main concern is enhanced background staining and nonspecific bindings, especially in cases where 1) the target T cell clonotype is of low frequency such as neoantigen specific T cells, 2) during sorting practices for single cell analysis. This potential challenge for researchers can be effectively addressed with a focus on specificity. MBLI ‘s T cells detection tools focus on identifying specific MHC/peptide complexes by incorporating a patented mutation of the α3 domain in their HLA class I tetramers. MBLI is the only manufacturer of MHC multimers with this advanced technology to enhance specificity for the antigen-specific T cell receptors. References: 1. Goodridge HS, Wolf AJ, Underhill DM. Beta-glucan recognition by the innate immune system. Immunol Rev. 2009 Jul;230(1):38-50. 2. Cognigni, Valeria, et al. "Potential benefit of β-glucans as adjuvant therapy in immuno-oncology: A review." Exploration of Targeted Anti-tumor Therapy 2.2 (2021): 122. 3. Pelizon A.C., Kaneno R., Soares A., Meira D.A., Sartori A. Immunomodulatory activities associated with β-glucan derived from Saccharomyces cerevisiae. Physiol. Res. 2005;54:557–564. 4. Wang Z, La Rosa C, Maas R, Ly H, Brewer J, Mekhoubad S, Daftarian P, Longmate J, Britt WJ, Diamond DJ. Recombinant modified vaccinia virus Ankara expressing a soluble form of glycoprotein B causes durable immunity and neutralizing antibodies against multiple strains of human cytomegalovirus. J Virol. 2004 Apr;78(8):3965-76. 5. Zhong X, Wang G, Li F, Fang S, Zhou S, Ishiwata A, Tonevitsky AG, Shkurnikov M, Cai H, Ding F. Immunomodulatory Effect and Biological Significance of β-Glucans. Pharmaceutics. 2023 May 29;15(6):1615. 6. Zhong X, Wang G, Li F, Fang S, Zhou S, Ishiwata A, Tonevitsky AG, Shkurnikov M, Cai H, Ding F. Immunomodulatory Effect and Biological Significance of β-Glucans. Pharmaceutics. 2023 May 29;15(6):1615. 7. Chan, G.CF., Chan, W.K. & Sze, D.MY. The effects of β-glucan on human immune and cancer cells. J Hematol Oncol 2, 25 (2009). 8. Pelizon AC, Kaneno R, Soares AM, Meira DA, Sartori A. Immunomodulatory activities associated with beta-glucan derived from Saccharomyces cerevisiae. Physiol Res. 2005;54(5):557-64. 9. Valeria Cognigni, et al. Potential benefit of β-glucans as adjuvant therapy in immuno-oncology: a review Explor. Target. Anti Tumor Ther., 2 (2021), pp. 122-138 10. Bose N, Chan AS, Guerrero F, Maristany CM, Qiu X, Walsh RM, Ertelt KE, Jonas AB, Gorden KB, Dudney CM, Wurst LR, Danielson ME, Elmasry N, Magee AS, Patchen ML, Vasilakos JP. Binding of Soluble Yeast β-Glucan to Human Neutrophils and Monocytes is Complement-Dependent. Front Immunol. 2013 Aug 12;4:230. 11. Chan, G.CF., Chan, W.K. & Sze, D.MY. The effects of β-glucan on human immune and cancer cells. J Hematol Oncol 2, 25 (2009). “β-glucans in fact can directly bind to specific receptors of immune cells”. 12. Ding J, Feng T, Ning Y, Li W, Wu Q, Qian K, Wang Y, Qi C. β-Glucan enhances cytotoxic T lymphocyte responses by activation of human monocyte-derived dendritic cells via the PI3K/AKT pathway. Hum Immunol. 2015 Mar;76(2-3):146-54. 13. Soeiro VC, Melo KR, Alves MG, Medeiros MJ, Grilo ML, Almeida-Lima J, Pontes DL, Costa LS, Rocha HA. Dextran: Influence of Molecular Weight in Antioxidant Properties and Immunomodulatory Potential. Int J Mol Sci. 2016 Aug 19;17(8):1340. Tags: Tetramer, Immunology, t cell, MHC, T-Cell Detection, MHC Tetramer, dextran multimer READ MORE BLOGS FROM MBLI

by Virginia Litwin, PhD , independent, virginiam.litwin@gmail.com Abstract One of the primary objectives for the application of flow cytometry in any testing environment should be measurement assurance, i.e., the generation of reliable and reproducible results. This goal can only be realized using multiple controls during each stage of the measurement process: instrument qualification, instrument monitoring, panel design, testing, and assay monitoring. There have been numerous global initiatives focusing on measurement consistency in flow cytometry. This review will provide a high-level overview of the major global initiatives related to achieving measurement assurance in flow cytometry and the current recommendations for best practices. The primary focus of this manuscript will be on the controls, calibrators, and standards used in flow cytometry. Introduction The flow cytometry community is witnessing significant advances in instrumentation, reagents (fluorescent probes), and software analysis tools such as artificial intelligence (AI) for single-cell analysis (1). The use of flow cytometry is expanding beyond biomedical research and clinical settings into drug discovery and development, cell and gene therapy, transfusion medicine, hematopathology, botany, marine and environmental biology, food sciences, and animal husbandry. The importance of generating accurate flow cytometry data is only increasing, especially as it becomes indispensable to applications such as measurable residual disease (MRD) in oncology, evaluation of biomarkers supporting drug development, and cell therapy manufacturing. In this way, flow cytometric data enhances Investigational New Drug (IND) applications and contributes to key decisions regarding therapeutic regimens. The critical quality attributes (CQA) in cell therapy manufacturing include flow cytometric evaluation. As the new applications for flow cytometry expand, the requirement for high-quality data also increases. This, in turn, creates the need to redefine best practices, educate users regarding best practices, and finally, ensure these are implemented. Increased rigor in measurement is widely recognized as critical to advancing biosciences and biotechnology. The interest in high-quality and combinable data sets is not new to the field of flow cytometry (2, 3). As the technology has evolved and as the applications have expanded, various consortia and working groups have recognized the need to establish new best practice guidelines and refine existing guidance documentation. Their aims have been to identify the underlying obstacles in the field and put forth recommendations to overcome existing limitations in generating standardized and uniform results. The AIDS Clinical Trial Group (ACTG) was one of the first groups to conduct an inter-laboratory study and put forth best practices recommendations in the 1980s with the goal of obtaining consistent data for all testing laboratories (4). In 1996, the International Society of Hematotherapy and Graft Engineering (ISHAGE) established guidelines for CD34+ progenitor enumeration, a procedure that is now used to evaluate hematopoietic stem cell mobilization, among other clinical applications (5). The EuroFlow Consortium began to publish their recommendations for leukemia and lymphoma testing in 2007 (6). Recommendations specific to the validation of flow cytometric methods were first published by the American Association for Pharmaceutical Scientists (AAPS) first in 2011 and again in 2013 by a collaborative effort between the International Clinical Cytometry Society (ICCS) and the International Society for Standards in Hematology (ISLH)(7, 8). In 2021, the Clinical and Laboratory Standards Institute’s (CLSI) Guidance H62 for the validation of flow cytometric methods was published (9). More recently, the Extracellular Vesicle (EV) Flow Cytometry Working Group (EV FC WG) published recommendations around the measurement of EV in 2022. (10). These recommendations and guidelines cover most aspects of measurement, from pre-analytical steps (including sample collection, storage, and processing), to instrumentation (including initial qualification, calibration, standardization, and daily monitoring) and assay design (including panel design, sample staining, essential controls, gating, and reportable results) (Figure 1). Measurement Assurance in Flow Cytometry Measurement assurance is a structured process designed to ensure that measurements are adequate for their intended use. It is accomplished by treating the assay as a measurement process. First, different elements that contribute to the measurement are defined, and then processes for each element are designed (Figure 1). Next, quality assurance (QA) and quality control (QC) practices are established to maintain a controlled environment that can produce high-quality, robust, and validated measurements for cell characterization, and which is able to consistently generate reliable data over a long period of time. Finally, key performance indicators for each element are defined along with processes for maintaining and monitoring performance. Figure 1. Measurement Assurance in Flow Cytometry. All elements which are part of the process of generating the measurement contribute to assuring that the measurement will be adequate for its intended use. In order to achieve comprehensive measurement assurance in flow cytometry, QA and QC procedures span from the initial instrument qualification to assay development and validation. These activities are considered the pre-analytical or pre-examination activities. During testing or the examination phase, separate QA and QC procedures should be initiated in order to monitor the environment, the instrument, the reagents, and the assay, as well as staff training. The purpose of these QA and QC procedures is to ensure that the instrument continues to perform in the qualified state, new lots of reagents are comparable to existing lots, the assay continues to perform in the validated state, and that current and new staff continue to be fully competent. Measurement assurance activities in flow cytometry require the use of both calibrators and controls (Tables 1 and 2). The calibrators are generally beads with known values for chosen characteristics and are used for instrument evaluation, adjustment, and monitoring. Beads may be hard-dyed and fluoresce over a broad spectral range, or they may be surface- labeled and spectrally matched to the fluorochromes used to stain cells. Spectrally matched beads are used for standardization and calibration across instruments that have different lasers and/or filters. Controls are generally understood to be biological samples intended to monitor all aspects of the assay and sample processing. When processed in the same manner as the intended use samples, the controls should produce results within a pre-defined range based on the performance characterization of the method. When deciding the best controls for a given process (i.e., cells or beads, spectrally matched or broad-spectrum), the objectives of each process and the objectives of the control procedure must be fully understood. Instrument At each stage of an instrument’s lifecycle, multiple processes are executed to ensure that results from the instrument will have the quality required for their intended use. Instrument qualification, calibration, standardization, and subsequent routine monitoring each provide different degrees of certainty related to instrument performance and, in turn, measurement assurance. Table 1. Instrument Calibrators. A variety of particles are used during the various phases of instrument QA and QC Table 2. Assay Control Materials. Biological controls are required at all stages of the assay lifecycle. Qualification When first placing a new instrument in the laboratory, the testing laboratory should qualify the instrument. The level of rigor for the instrument qualification procedure and the associated documentation will depend on the regulatory environment of the testing laboratory. Instrument qualification is a multistep process that aims to ensure that reliable data can be generated from each assay throughout instrument’s lifecycle. Best practices for instrument qualification are described in depth in CLSI H62 and by Green et al. (9, 11). Briefly, instrument qualification involves three phases: 1) Installation Qualification (IQ); 2) Operational Qualification (OQ); 3) Performance Qualification (PQ). IQ entails assessing the facilities’ requirements for the instrument, for example, hardware, software, physical space, and electrical requirements. During OQ, the basic functionality of the instrument is verified, including but not limited to the software functionality, system alerts, optical precision and sample acquisition. IQ and OQ are often performed by the manufacturer during installation to demonstrate that the instrument and its associated software are installed and functioning per the manufacturer’s specification and the user’s requirements. PQ is a more extensive process, which is most often performed by the testing laboratory. PQ includes instrument optimization and extended longitudinal performance (Table 3). Optimization Optimization examines a wide array of critical instrument parameters: the efficiency and performance of optical filters, dichroic mirror reflection and transmission, the timing of lasers (laser delay), laser power, the length of time set to collect instrument signals (e.g., window extension), amplifier linearity, electronic noise, and synchronization of the area and peak height signals (e.g., area scaling factor) (12, 13). Table 3. Performance Qualification. A variety of instrument functionality is evaluated during Performance Qualification. Calibration Detailed procedures for instrument calibration are described in depth by Perfetto et al (13). Briefly, calibration is accomplished by measuring fluorescence over a range of photomultiplier tube (PMT) voltages in order to determine the PMT voltage range and linearity. These procedures also apply to other excitation and detection modalities, including solid-state sources and spectral analyzers. Instrument calibration is required for the objective and quantitative comparison of inter-inter instrument and inter-laboratory longitudinal data. Daily Monitoring Once the instrument has been qualified and put into use, it should subsequently be operated under QA/ QC conditions to maintain the instrument within predetermined bounds and ensure that results will vary only within certain pre-defined limits (Table 4). The daily QA/QC practices, as described in CLSI H62, are intended to monitor instrument variation to verify and document that the system is suitable for daily use (9). In addition, data from the daily QA/QC can be used to track trends in instrument performance, such as detector sensitivity or changes in the filters, thereby providing information about potential future issues or the need for repairs. Assay Development, Optimization, and Validation The development of a multi-color panel is an iterative process. Best practices for multicolor panel design (assay development) and validation are well described in the literature (9, 14, 15). Typically, both commercially available biological controls such as preserved whole blood products or lyophilized PBMC and intended use samples are used. During panel design, biological controls can be used to screen monoclonal antibodies (mAb) and demonstrate the overall assay specificity (i.e., that the assay measures what it was intended to measure). Another important step in panel design is to optimize the fluorescence compensation and minimize spillover, as described in (16). Compensation beads or single stained cells can be used for this purpose. Because of the differences in light scatter and autofluorescence between cells and beads, there is considerable debate whether cells or beads are preferable for creating the compensation matrix and spillover spread matrix (SSM). During analytical method validation, biological controls are useful when characterizing inter-assay and inter- laboratory performance, particularly when sample stability is limited (7, 9). Nonetheless, commercially available biological controls have several drawbacks. Their primary limitation is that they are not provided with meaningful target values beyond the primary lymphocyte subsets. Thus, they cannot be used to assess true accuracy and linearity, as discussed in depth in CLIS H62. Despite this limitation, the commercially available biological controls are well suited for inter-assay and inter-laboratory comparisons (9). Other limitations are discussed below. Daily Testing and Routine QC Biological process controls should be included in each analytical run, especially when flow cytometry is used to support patient care and treatment or as biomarkers in longitudinal clinical trials. When used in this capacity, the performance of the process controls will be one of the primary criteria for evaluating and accepting each analytical run. If the process controls are within the pre- established ranges, there is assurance that the assay was performed according to the SOP, the reagents have not degraded, and the instrument is operating within predefined specifications. Biological controls are also a critical component of other QC processes in the flow cytometry laboratory; for example, they are often used to evaluate new lots of mAb, for staff training, and as a part of troubleshooting activities. The ideal process control material would be a biological control with similar properties to the intended use samples, delivered equal or better assay precision compared to the intended use samples, and had a reasonably long shelf-life. Various process control materials have been used in different laboratories, such as; commercially available preserved blood, commercially available lyophilized or cryopreserved PBMC, in-house generated cryopreserved PBMC, in- house generated cell line banks, and fresh normal donor samples (Table 4). Each of these materials presents advantages and disadvantages, and unfortunately a perfect biological control material does not exist to date. The general consensus is that the field could benefit greatly from the introduction of novel, biologically- relevant process controls. Commercially available preserved blood controls are suitable biological process controls for basic methods such as assays which monitor only the major lymphocyte populations (Total T cells, CD4 T cells, CD8 T cells, B cells, NK cells). The major limitation of these products is limited stability, resulting in the laboratory’s need to frequently re-establish new ranges for each new lot of biological control material. This is costly as it is a time-consuming process that uses large quantities of reagent and ties up instrument time. Unfortunately, for these reasons, some laboratories choose to reduce their usage of this valuable quality monitoring tool in order to reduce operating costs. The preserved blood products have additional limitations for higher-dimensional assays that evaluate more extensive cell subsets. Their primary drawback is that not all of the cell populations evaluated in higher dimensional assays will be detectable in the control material. As a result, the entire assay is not controlled for using this type of control. An additional disadvantage is that the commercial processing of these biological controls can result in a loss of more labile antigens, which can result in decreased resolution of cell subsets expressing low levels of these antigens. In these situations, the control material will may greater variability than the intended use sample, which will decrease confidence in the reported data and could also lead to the unnecessary cancellation of an analytical run. Lyophilized PBMC controls have greater stability than preserved blood controls; however, they are not ideal in assays designed for whole blood or bone marrow matrices as they are not similar to the intended use samples and would not control for cell lysis steps. Table 4. Extended Performance Qualification. Performance Qualification does not end after successful installation, it includes routine QA/QC and extends throughout the lifecycle of the instrument. The purpose is to ensure that the qualified instrument continues to perform as expected. There are few commercially available biological controls for leukemia and lymphoma immunophenotyping panels. Many laboratories will use internal positive and negative populations for reagent monitoring. Although this is an accepted practice, it does not allow the laboratory to monitor the assay performance over time, which is an extremely valuable QA/QC tool for adequately detecting reagent degradation or instrument decline. Some laboratories will create their own QC material with cell lines or ex vivo PBMC activation. Maintaining cell lines is a labor-intensive practice. If the laboratory does not have adequate quality practices for consistent cell line propagation, viability monitoring, cryopreservation, and thawing, the in-house generated, cell line-derived process controls run the risk of introducing variability to the quality monitoring process. The use of healthy donor samples as process controls is another common practice; however, due to intra- and/ or inter-donor variability, healthy donor samples are not ideal process controls. A comparison of preserved commercial controls to healthy donor samples reveals that assay variability appears higher with healthy donor controls than commercially available preserved blood controls (Figure 2). This artificial increase in assay variability comes not from the assay but from the variability of the control material due to the intra- and/ or inter-donor variability of healthy donors. Figure 2. Assay Monitoring. The performance of an IVD assay for peripheral blood T cells was monitored with a commercially available whole blood control (orange dot) and healthy donor whole blood (navy square). Both QC materials were included in the same analytical runs. Assay variability appears higher with the healthy donor whole blood control. In summary, the ideal process control would be stable, yield consistent results, and, most importantly, not introduce its own variability. It is important that the variability observed during the monitoring process comes from the system being monitored, for example, the instrument, the reagent, the assay, the analyst, and the laboratory, not from the control material itself. Inter-laboratory Studies and Assay Transfers There are numerous different scenarios where flow cytometric methods are conducted in more than one testing laboratory (17). For example, in translational medicine, inter-laboratory studies are becoming more and more common. In drug development, assays are frequently transferred from one laboratory to another, either within the same institution or between institutions. Flow Cytometry used in global clinical trials requires that testing be conducted at multiple locations owing to both limited specimen stability and high shipping costs. In cell and gene therapy studies, the flow cytometry methods used to establish CQA for product release are also transferred from one laboratory to another as the therapy progresses along the drug development pathway. To generate consistent data sets from multiple instruments and multiple laboratories, the instruments and the assays should be standardized. In all laboratory settings, the instrument and the assay should be routinely monitored using control material per the established QA/QC practices, however, in inter- laboratory studies and assay transfers, these QA/QC processes are mandatory in order to ensure the delivery of high-quality, consistent, and combinable data. Moreover, many inter-laboratory studies, particularly longitudinal, global clinical trials, include the participation of laboratories located in different countries that are often geographically distant. These circumstances put additional requirements on the control material, such as the capacity to be shipped at ambient temperatures. The biohazard classification of the control material is an additional consideration given that some countries have import licensing procedures for biohazardous material, which can be cumbersome and difficult to navigate. Discussion In the past several years, the flow cytometry community has witnessed revolutionary advances in instrumentation, novel fluorophores, and data analysis approaches, such as those that now include AI (1). Some of the greatest excitement in flow cytometry is currently focused on the potential of implementing automated data analysis tools and unsupervised gating approaches. Many cytometrists think that the automation and standardization of data analysis is an essential requirement for ushering in the new era of high-dimensional, quantitative cytometry. However, one critical point that is often missing from discussions surrounding the future of data analysis is the need to demonstrate that the data submitted to the analysis tools are of suitable quality. The old cliché of garbage-in, garbage-out comes to mind. Thus, the implementation of the QA/QC processes for the instrument and the assay discussed herein should be broadly implemented, even in non-regulated testing laboratories. Process controls are crucial in the implementation of QA/QC programs. In flow cytometry, the best process controls are biological controls. They are required during assay development, optimization, validation, and monitoring as well as in inter- instrument and inter-laboratory standardization. Unfortunately—and despite the well-documented need for improved biological process controls— the development of biological control material for flow cytometry has not progressed in parallel with the advances in instrumentation, reagents, and software (7, 8, 18, 19). The CLSI guideline H42-A2 (19) takes a conservative approach, stating, “There are at present no standards which can be used to check the accuracy of flow cytometric test results.” At CYTO 2018, a workshop on the topic of control cells was held with the intention of defining the pathway to overcome the challenge issued by the lack of readily available biological control materials (18). One conclusion from this workshop was that biological control material for flow cytometry needs to evolve in tandem with the instruments, reagents, and software approaches. Control cells are important yet remain challenging for the field of flow cytometry. There remains an unmet need for innovative new solutions for this critical aspect of generating high- quality results. Bibliography Mitra-Kaushik S, Mehta-Damani A, Stewart JJ, Green C, Litwin V, Gonneau C. The evolution of single cell analysis and utility in drug development. The AAPS Journal. 2021, The AAPS Journal (2021) 23:98 DOI: 10.1208/s12248-021-00633-6. Gonneau C, Wang L, Mitra-Kaushik S, Trampont PC, Litwin V. Progress towards global standardization for quantitative flow cytometry. Bioanalysis. 2021 Sep;13(21):1591-5. Kalina T. Reproducibility of flow cytometry through standardization: opportunities and challenges. Cytometry Part A. 2020 Feb;97(2):137-47 Paxton H, Kidd P, Landay A, Giorgi J, Flomenberg N, Walker E, Valentine F, Fahey J, Gelman R. Results of the flow cytometry ACTG quality control program: analysis and findings. Clinical immunology and immunopathology. 1989 Jul 1;52(1):68-84. Sutherland DR, Anderson L, Keeney M et al. The ISHAGE guidelines for CD34+ cell determination by flow cytometry. J Hematother 1996;5:213-26. Szczepanski T. Why and how to quantify minimal residual disease in acute lymphoblastic leukemia?. Leukemia. 2007 Apr;21(4):622- 6. O’Hara, D., Xu, Y. Lianz, E., Reddy, M., Wu, D., and Litwin, V. Recommendations for the Validation of Flow Cytometric Testing During Drug Development: II Assays. Journal of Immunological Methods, 363:120-134, 2011. Wood, B., Jevremovic, D., Béné, MC., Yan, M,. Jacobs, P., Litwin, V. Validation of cell-based fluorescence assays: Practice guidelines from the ICSH and ICCS – Part V – assay performance criteria. Cytometry Part B: Clinical Cytometry. 84:315, 2013. Validation of assays performed by flow cytometry. 1st ed. CLSI document H62. Wayne, PA: Clinical Laboratory Standards Institute; 2021. Welsh JA, Van Der Pol E, Arkesteijn GJ, Bremer M, Brisson A, Coumans F, Dignat-George F, Duggan E, Ghiran I, Giebel B, Görgens A. MIFlowCyt-EV: A framework for standardized reporting of extracellular vesicle flow cytometry experiments. Journal of extracellular vesicles. 2020 Sep;9(1):1713526. Green CL, Brown L, Stewart JJ, Xu Y, Litwin V, Mc Closkey TW. Recommendations for the validation of flow cytometric testing during drug development: I instrumentation. Journal of immunological methods. 2011 Jan 5;363(2):104-19. Wang, L. and Hoffman, R.A. 2017. Standardization, calibration, and control in flow cytometry. Curr. Protoc. Cytom. 79:1.3.1-1.3.27. doi: 10.1002 Perfetto SP, Ambrozak D, Nguyen R, Chattopadhyay P, Roederer M. Quality assurance for polychromatic flow cytometry. Nature protocols. 2006 Aug;1(3):1522-30. Ferrer-Font L, Pellefigues C, Mayer JU, Small SJ, Jaimes MC, Price KM. Panel design and optimization for high-dimensional immunophenotyping assays using spectral flow cytometry. Current protocols in cytometry. 2020 Mar;92(1):e70. Cossarizza, A., et al. (2019). Guidelines for the use of flow cytometry and cell sorting in immunological studies. European journal of immunology, 49(10), 1457-1973. Nguyen R, Perfetto S, Mahnke YD, Chattopadhyay P, Roederer M. Quantifying spillover spreading for comparing instrument performance and aiding in multicolor panel design. Cytometry Part A. 2013 Mar;83(3):306-15. Cabanski M, Oldaker T, Stewart JJ, Selliah N, Eck S, Green C, Litwin V, Vitaliti A. Flow cytometric method transfer: Recommendations for best practice. Cytometry Part B: Clinical Cytometry. 2021 Jan;100(1):52-62. Czechowska, K, et al. Cyt-Geist: Current and Future Challenges in Cytometry: Reports of the CYTO 2018 Conference Workshops. Cytometry Part A 95A: 598–644, 2019 Enumeration of Immunologically Defined Cell Populations by Flow Cytometry. 2nd ed. CLSI document H42. Wayne, PA: Clinical Laboratory Standards Institute; 2007.