In its lowest-altitude mapping orbit, at a distance of 240 miles (385 kilometers) from Ceres, Dawn has provided scientists with spectacular views of the dwarf planet. Haulani Crater, with a diameter of 21 miles (34 kilometers), shows evidence of landslides from its crater rim. Smooth material and a central ridge stand out on its floor. An enhanced false-color view allows scientists to gain insight into materials and how they relate to surface morphology. This image shows rays of bluish ejected material. The color blue in such views has been associated with young features on Ceres. "Haulani perfectly displays the properties we would expect from a fresh impact into the surface of Ceres. The crater floor is largely free of impacts, and it contrasts sharply in color from older parts of the surface," said Martin Hoffmann, co-investigator on the Dawn framing camera team, based at the Max Planck Institute for Solar System Research, Göttingen, Germany. The crater's polygonal nature (meaning it resembles a shape made of straight lines) is noteworthy because most craters seen on other planetary bodies, including Earth, are nearly circular. The straight edges of some Cerean craters, including Haulani, result from pre-existing stress patterns and faults beneath the surface. A hidden treasure on Ceres is the 6-mile-wide (10-kilometer-wide) Oxo Crater, which is the second-brightest feature on Ceres (only Occator's central area is brighter). Oxo lies near the 0 degree meridian that defines the edge of many Ceres maps, making this small feature easy to overlook. Oxo is also unique because of the relatively large "slump" in its crater rim, where a mass of material has dropped below the surface. Dawn science team members are also examining the signatures of minerals on the crater floor, which appear different than elsewhere on Ceres. "Little Oxo may be poised to make a big contribution to understanding the upper crust of Ceres," said Chris Russell, principal investigator of the mission, based at the University of California, Los Angeles. The 6-mile-wide (10-kilometer-wide) crater named Oxo Crater is the second-brightest feature on Ceres. Only Occator's central area is brighter. Oxo lies near the 0 degree meridian that defines the edge of many Ceres maps, making this small feature easy to overlook. NASA Dawn spacecraft took this image in its low-altitude mapping orbit, at a distance of 240 miles (385 kilometers) from the surface of Ceres. Oxo is also unique because of the relatively large "slump" in its crater rim, where a mass of material has dropped below the surface. Dawn science team members are also examining the signatures of minerals on the crater floor, which appear different than elsewhere on Ceres. The image has been rotated so that north on Ceres is up. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/PSI Explore further: Ceres' bright spots seen in striking new detail
The institutions will serve as "platforms" to develop new bulk and thin film crystalline hard materials through state-of-the-art instrumentation. They will foster an environment that combines multidisciplinary expertise with the best tools available, providing access to the instrumentation, data and new materials created. The Cornell University award is a multi-institution effort in collaboration with Johns Hopkins University, Clark Atlanta University and Princeton University. The National Science Foundation (NSF) will provide up to $25 million over the next five years to support the platforms, with each eligible for a one-time, five-year renewal. The platforms, which add to NSF's portfolio of mid-scale infrastructure and instrumentation, will advance a focused research area of national importance and expand access beyond traditional user facilities. "We see the platforms as pushing the frontiers in materials research," said Fleming Crim, NSF assistant director for mathematical and physical sciences (MPS). "In its first call for proposals, NSF is focusing on crystal growth because the U.S. has fallen behind in this area of science after having been a global leader in material synthesis, which is essential for advancing basic materials research and will add to the important investment the foundation is making in mid-scale instrumentation." The MPS mid-scale research infrastructure program, begun over the last few years to meet critical research needs, has received strong support from the community. "MIPs will serve as focal points that promote cross-fertilization of ideas between internal and external researchers, thanks to their unique convergence of expertise," said Linda Sapochak, acting director for NSF's Materials Research Division. "To accelerate research outcomes, the platforms will focus on a targeted materials grand challenge and/or technological outcome that addresses a national priority. Along with the discovery of new materials, research conducted at a MIP will lead to the understanding of new materials phenomena." The platforms program was inspired by the paradigm the administration set forth in its Materials Genome Initiative. Launched in 2011, the initiative seeks to "discover, manufacture and deploy advanced materials in half the time and at a fraction of the cost." The MIPs program will enable researchers using the platforms to develop new materials, new techniques and the next generation of instrumentation that will lead to understanding and discovering all kinds of new phenomena. Additionally, the processes used by these platforms will move between theory, measurement and actual fabrication with the aim of accelerating discovery of new materials in half the time. The science will accelerate the development of technologies in a wide range of areas, such as microelectronics, fuel and solar cells and new biomaterials, generating economic gains for the nation. The effort is data-intensive and researchers not directly involved with the platform will also have access to, and benefit from, the generated data. The awardees will act as "nexus of activity" for a focused research theme, where platforms are equipped with user facilities. Researchers from across the nation who also engage in this area of research will be able to use these resources to accelerate their own work. Access to the platform is free to academic users and includes not just instrumentation, but also expertise in synthesis, characterization, and theory/modeling/simulation. Additionally, the platforms will enable researchers to work in new ways, fostering new approaches to multidisciplinary education and training. "Without question, one of the most exciting aspects to these awards will be to see just how quickly these platforms can accelerate the pace of materials development," said Sean L. Jones, NSF materials research program director. "The awards are fairly complementary to one another and accelerate research in two distinct material systems likely to have a significant impact on technology as they transform the field at the most fundamental level." Cornell's Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials (PARADIM) will focus primarily on oxide and oxide-based two-dimensional films on new substrates—physical materials meant for next generation electronics. Researchers using the platform will search for "new materials" where the combination of 2-D materials coupled with novel substrates will yield new phenomena, such as smaller, faster, smarter computer chips. More information about this platform is available here. Using Penn State University's platform, researchers will study metal chalcogenide materials, which include sulfides, selenides and tellurides. Metal chalcogenides have become quite popular for a range of technical applications, including digital circuits and flexible electronics. Called the Two-Dimensional Crystal Consortium (2DCC), the new facility at Penn State will foster the growth of a national community of users who develop new materials for next-generation electronics that are faster, use less energy, and can be built on flexible substrates, as well as other applications. More information about this platform is available here. Explore further: Discovery of the specific properties of graphite-based carbon materials
To overcome this obstacle a group of researchers from several institutions in Toronto have conducted organ-level and sub-organ level computational, in vitro, and in vivo studies using quantum dots, gold nanoparticles, and silica nanoparticles to better understand the mononuclear phagocyte system and the mechanism by which nanoparticles are sequestered. They found that blood flow rate, cellular phenotype, and physical position in the liver all play a role in nanoparticle uptake. They suggest that future work ought to involve not only nanoparticle design, but some kind of liver pre-conditioning. Their work appears in Nature Materials. Nanoparticles can be functionalized in such a way that the particle targets a particular cell type. This holds great promise for cancer and other targeted therapies. However, when nanotherapies are tested in the body, the nanoparticle is cleared from the bloodstream via the mononuclear phagocyte system (MPS). This holds true for all types of nanoparticles. Tsoi, et al. conducted whole-organ and sub-organ analyses to better understand how the MPS system sequesters nanoparticles. For their experiments, they focused on non-degradable "hard" nanoparticles: quantum dots, gold nanoparticles, and silica nanoparticles. On the whole organ level, Tsoi, et al. found that quantum dots are first cleared by the cells near the portal triad and that there is a clearance gradient through the liver sinusoid during the first pass. Blood flows into the liver through the portal triad and out through the central vein. This was also observed with gold nanoparticles irrespective of surface functionalization, although protein adsorption seemed to play a role in nanoparticle uptake. The next area of investigation is whether blood flow rate plays a role in nanoparticle sequestration. Blood flow slows down once it hits the liver (from 10-100 cm s-1 to 200-800 μm s-1). Tsoi, et al. developed a mathematical model to describe blood flow within the liver and the probability of nanoparticle sequestration. They then compared their computational results to the results of cytometry studies with the rats that were treated with quantum dots in the test for nanoparticle accumulation. Notably, while advection is the dominant influence on blood flow in the body, diffusion is the dominant influence in the liver. They found that the liver was 102 to 103 times more likely to sequester nanomaterials and that particle size played a role – the larger the particle, the more likely it was absorbed by the liver. At the sub-organ level, Tsoi, et al. looked at which cell types play the biggest role in nanoparticle uptake. Studies to determine cell uptake of quantum dots showed that Kupffer cells adsorbed the largest volume of quantum dots, as expected. However, what was surprising was the number of particles internalized by B cells. B cells seem to play a much bigger role in nanoparticle uptake than was once thought, although Kupffer cells are still the key cells in removing nanoparticles. Other cell types, including endothelial cells, also played a role in removing nanoparticles. Next, Tsoi, et al. tested whether organ architecture affects nanoparticle uptake in the liver by studying the sequestration process in the spleen. They found that of the nanoparticles that were removed by the spleen, almost all of them were located in the red pulp region. This is where blood flow decreases compared to the flow throughout the body. While some nanoparticles resided in the spleen, spleen macrophages internalized fewer nanoparticles than Kupffer cells within the liver. This was confirmed with comparative in vitro and in vivo studies, and demonstrates that organ architecture cell-type play a role in nanoparticle uptake. This research provides important insights in how to overcome nanoparticle uptake by the MPS. Typically researchers focus on the nanoparticle design, but this study suggests that bodily environment plays an important role in nanoparticle sequestration. The authors suggest manipulating the host environment as a complementary strategy to nanoparticle optimization. Preliminary tests show that two possible avenues are changing the blood flow rate through the liver and changing the phenotype of certain cells so they are not prone to nanomaterial uptake. More information: Kim M. Tsoi et al. Mechanism of hard-nanomaterial clearance by the liver, Nature Materials (2016). DOI: 10.1038/nmat4718 Abstract The liver and spleen are major biological barriers to translating nanomedicines because they sequester the majority of administered nanomaterials and prevent delivery to diseased tissue. Here we examined the blood clearance mechanism of administered hard nanomaterials in relation to blood flow dynamics, organ microarchitecture and cellular phenotype. We found that nanomaterial velocity reduces 1,000-fold as they enter and traverse the liver, leading to 7.5 times more nanomaterial interaction with hepatic cells relative to peripheral cells. In the liver, Kupffer cells (84.8 ± 6.4%), hepatic B cells (81.5 ± 9.3%) and liver sinusoidal endothelial cells (64.6 ± 13.7%) interacted with administered PEGylated quantum dots, but splenic macrophages took up less material (25.4 ± 10.1%) due to differences in phenotype. The uptake patterns were similar for two other nanomaterial types and five different surface chemistries. Potential new strategies to overcome off-target nanomaterial accumulation may involve manipulating intra-organ flow dynamics and modulating the cellular phenotype to alter hepatic cell interactions.
In 2013, IceCube researchers made an important contribution to astrophysics when they reported the first detection of high energy cosmic neutrinos, opening a new astronomical window to the universe and some of its most violent phenomena. The five-year, $35 million cooperative agreement calls for the continued operation and management of the observatory, which is located at NSF's Amundsen-Scott South Pole Station. The agreement begins April 1, and may be renewed for another five-year period if the detector and collaboration continue to operate successfully. Funding for IceCube comes through an award from the Division of Polar Programs in NSF's Geosciences Directorate and from the Directorate for Mathematical and Physical Sciences (MPS) Division of Physics. Through the Division of Polar Programs, NSF manages the U.S. Antarctic Program that supports researchers at universities throughout the country. The program also provides infrastructure to support researchers in the field. "NSF is excited to support the science made possible by the IceCube Observatory because it's at the cutting edge of discovery," said Scott Borg, head of Polar Programs' Antarctic sciences section. "But to make ambitious research of this kind a reality requires cooperation within the agency, which is why we're delighted that our support for IceCube is in partnership with MPS. It's also science on a global scale, relying on strong international cooperation to be successful." The collaboration that operates the IceCube observatory includes individuals representing 47 institutions from 12 different countries. It includes sub-awards to the Lawrence Berkeley National Laboratory, Pennsylvania State University, the University of Delaware, the University of Maryland, the University of Alabama at Tuscaloosa, Michigan State University and the University of Wisconsin-River Falls. Since IceCube's inception 15 years ago and the completion of its construction five years ago—centered around a detector array consisting of 5,000 optical sensors frozen in the ice a mile beneath the South Pole—has been administered through UW-Madison, in recent years under the auspices of the Wisconsin IceCube Particle Astrophysics Center (WIPAC). "This is extremely good news," says Francis Halzen, a UW-Madison professor of physics and the principal investigator for the project. "Over the years, we have come to know what it takes to successfully operate the detector." IceCube was the first scientific instrument to detect ultra high-energy neutrinos from beyond our solar system. The neutrinos packed a billion times more energy than those detected in conjunction with the 1987 supernova observed in the Large Magellanic Cloud. Recent reports from the IceCube collaboration have confirmed the observatory's detection of high-energy neutrinos from beyond our galaxy—so-called cosmic neutrinos. Neutrinos are nearly massless particles created in nuclear reactions and. In nature, they are created by some of the most energetic events in the universe. Scientists believe colliding black holes, the violent cores of galaxies, supernovas and pulsars accelerate neutrinos, many billions of which pass through the Earth every second. Because they have almost no mass and rarely interact with matter, they are extremely difficult to detect and require instruments the size of IceCube—which occupies a cubic kilometer of Antarctic ice—to capture the fleeting bursts of light created when the occasional neutrino crashes into another particle. But the elusive qualities that make neutrinos so hard to detect also make them interesting to scientists. Since the particles glide through space unhindered by stars, planets and the powerful magnetic fields that pock the universe, they remain virtually pristine and harbor valuable clues about their yet-to-be-confirmed sources. IceCube has proven a workhorse of a telescope, according to Halzen. It remains operational 99 percent of the time, and has so far detected more than a million neutrinos—"A few hundred of which are astronomically interesting," Halzen said. "Five years ago, it was about discovering cosmic neutrinos. Now it's about doing astronomy and particle physics with them," notes Halzen of the quest to follow the particles' tracks back to their sources, a feat yet to be accomplished. Olga Botner, the IceCube collaboration spokesperson and a professor of physics and astronomy at Sweden's Uppsala University, said that "All over the world, IceCube is considered the flagship of neutrino astronomy." "IceCube's discovery of extraterrestrial neutrinos is a major breakthrough and a crucial first step into as yet unexplored parts of our violent universe," she said. "It also represents a step towards the realization of a 50 years old dream—to figure out what cosmic upheavals create the ultra-high energy cosmic rays, detected on Earth with energies millions of times larger than those achievable by even the most powerful man-made accelerators." Headquartered at UW-Madison, IceCube includes a staff of nearly 60 scientists, engineers and technicians in Madison. "There are many technical challenges underlying the operation of a large neutrino observatory at the South Pole, that would be hard to anticipate," says Kael Hanson, IceCube's director of operations and a UW-Madison professor of physics. IceCube's complexity, ability to gather large data sets, and standing among the world's frontline astrophysical detectors makes it a contributor to emerging computational technologies for managing and analyzing novel scientific information. Halzen says the performance of the IceCube detector has steadily improved and a key goal will be to speed up the analysis of neutrinos of interest in order to quickly alert other observatories. "We're going to detect interesting neutrinos in real time and we can send word to other observatories," Halzen said. "If we can do it in real time, we can be much more effective and we can alert, for example, optical observatories and other detectors" for combined observing. If neutrino detectors, and possibly also gravitational wave detectors, can provide early warnings to other telescopes, "We might have the astronomical event of the 21st century," Halzen said. Explore further: IceCube Neutrino Observatory reports first evidence for extraterrestrial high-energy neutrinos
News Article | August 25, 2016
The Rosetta spacecraft is living out its final days at Comet 67P/Churyumov–Gerasimenko. Scheduled to crash into the comet on September 30, the orbiter will finally rejoin its longtime companion, the recently deceased Philae lander (RIP, sweet prince). But though its days are numbered, Rosetta is still churning out spectacular imagery and data like a boss, including newly released pictures of a powerful outburst of gas and dust released by an avalanche on the comet’s surface. These eruptions are extremely capricious, so it’s rare for them to be observed at all, let alone from only 35 kilometers (22 miles) away. “Over the last year, Rosetta has shown that although activity can be prolonged, when it comes to outbursts, the timing is highly unpredictable, so catching an event like this was pure luck,” said Matt Taylor, ESA’s Rosetta project scientist, in a statement. The majority of Rosetta’s instruments recorded the outburst. Image: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; all data from Grün et al (2016) For months, researchers led by planetary scientist Eberhard Grün of the Max Planck Institute for Nuclear Physics mined this comprehensive data set for clues about the origins, dynamics, and scale of the outburst. The team’s findings will be published in a forthcoming issue of the Monthly Notices of the Royal Astronomical Society, but the short version is that eruption was likely sparked by a landslide along the steep slopes of the comet’s Atum region, caused by sudden exposure to sunlight after a long period in shadow. As ice rapidly sublimated into gas, Rosetta picked up a spike in temperature of 30℃ and a sixfold increase in ultraviolet brightness over the course of several hours. This prompted outgassing that weakened surface integrity and generated the landslide and geyser-like plume of material that followed it. Rosetta recorded the event with its cameras, dust collectors, gas analyzers, and temperature sensors. Even the orbiter’s star trackers (navigational aids that help orient Rosetta in space) detected an uptick in reflected light off the scattered detritus of the outburst. “It’s great to see the instrument teams working together on the important question of how cometary outbursts are triggered,” Taylor said. Even as it faces its impending doom, Rosetta continues to be a prolific scientific dynamo. We’ll miss you, old girl.