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  • richardmitnick 1:31 pm on July 15, 2018 Permalink | Reply
    Tags: , , PandaX - Particle and Astrophysical Xenon Detector and PandaX-II, , , UC Riverside   

    From UC Riverside: “In Search of Dark Matter” 

    UC Riverside bloc

    From UC Riverside

    July 12, 2018
    Iqbal Pittalwala

    Researchers, including a UC Riverside particle physicist, interpret new experimental data aimed at showing dark matter interacts with ordinary matter — an unmet challenge in modern physics.

    1
    Particle physicist Hai-Bo Yu is an assistant professor of physics and astronomy at UC Riverside. Photo credit: I. Pittalwala, UC Riverside.

    An international team of scientists that includes University of California, Riverside, physicist Hai-Bo Yu has imposed conditions on how dark matter may interact with ordinary matter — constraints that can help identify the elusive dark matter particle and detect it on Earth.

    Dark matter — nonluminous material in space — is understood to constitute 85 percent of the matter in the universe. Unlike normal matter, it does not absorb, reflect, or emit light, making it difficult to detect.

    Physicists are certain dark matter exists, having inferred this existence from the gravitational effect dark matter has on visible matter. What they are less certain of is how dark matter interacts with ordinary matter — or even if it does.

    In the search for direct detection of dark matter, the experimental focus has been on WIMPs, or weakly interacting massive particles, the hypothetical particles thought to make up dark matter.

    But Yu’s international research team invokes a different theory to challenge the WIMP paradigm: the self-interacting dark matter model, or SIDM, a well-motivated framework that can explain the full range of diversity observed in the galactic rotation curves. First proposed in 2000 by a pair of eminent astrophysicists, SIDM has regained popularity in both the particle physics and the astrophysics communities since around 2009, aided, in part, by work Yu and his collaborators did.

    Yu, a theorist in the Department of Physics and Astronomy at UCR, and Yong Yang, an experimentalist at Shanghai Jiaotong University in China, co-led the team analyzing and interpreting the latest data collected in 2016 and 2017 at PandaX-II, a xenon-based dark matter direct detection experiment in China (PandaX refers to Particle and Astrophysical Xenon Detector; PandaX-II refers to the experiment). Should a dark matter particle collide with PandaX-II’s liquefied xenon, the result would be two simultaneous signals: one of photons and the other of electrons.

    PandaX Experiment, located in the China Jin-Ping underground Laboratory

    PandaX II Dark Matter experiment at Jin-ping Underground Laboratory (CJPL) in Sichuan, China

    Yu explained that PandaX-II assumes dark matter “talks to” normal matter — that is, interacts with protons and neutrons — by means other than gravitational interaction (just gravitational interaction is not enough). The researchers then search for a signal that identifies this interaction. In addition, the PandaX-II collaboration assumes the “mediator particle,” mediating interactions between dark matter and normal matter, has far less mass than the mediator particle in the WIMP paradigm.

    “The WIMP paradigm assumes this mediator particle is very heavy — 100 to 1000 times the mass of a proton — or about the mass of the dark matter particle,” Yu said. “This paradigm has dominated the field for more than 30 years. In astrophysical observations, we don’t, however, see all its predictions. The SIDM model, on the other hand, assumes the mediator particle is about 0.001 times the mass of the dark matter particle, inferred from astrophysical observations from dwarf galaxies to galaxy clusters. The presence of such a light mediator could lead to smoking-gun signatures of SIDM in dark matter direct detection, as we suggested in an earlier theory paper [http://iopscience.iop.org/article/10.1088/1475-7516/2015/10/055/meta JCAP]. Now, we believe PandaX-II, one of the world’s most sensitive direct detection experiments, is poised to validate the SIDM model when a dark matter particle is detected.”

    The international team of researchers reports July 12 in Physical Review Letters the strongest limit on the interaction strength between dark matter and visible matter with a light mediator. The journal has selected the research paper as a highlight, a significant honor.

    “This is a particle physics constraint on a theory that has been used to understand astrophysical properties of dark matter,” said Flip Tanedo, a dark matter expert at UCR, who was not involved in the research. “The study highlights the complementary ways in which very different experiments are needed to search for dark matter. It also shows why theoretical physics plays a critical role to translate between these different kinds of searches. The study by Hai-Bo Yu and his colleagues interprets new experimental data in terms of a framework that makes it easy to connect to other types of experiments, especially astrophysical observations, and a much broader range of theories.”

    PandaX-II is located at the China Jinping Underground Laboratory, Sichuan Province, where pandas are abundant. The laboratory is the deepest underground laboratory in the world. PandaX-II had generated the largest dataset for dark matter detection when the analysis was performed. One of only three xenon-based dark matter direct detection experiments in the world, PandaX-II is one of the frontier facilities to search for extremely rare events where scientists hope to observe a dark matter particle interacting with ordinary matter and thus better understand the fundamental particle properties of dark matter.

    Particle physicists’ attempts to understand dark matter have yet to yield definitive evidence for dark matter in the lab.

    “The discovery of a dark matter particle interacting with ordinary matter is one of the holy grails of modern physics and represents the best hope to understand the fundamental, particle properties of dark matter,” Tanedo said.

    For the past decade, Yu, a world expert on SIDM, has led an effort to bridge particle physics and cosmology by looking for ways to understand dark matter’s particle properties from astrophysical data. He and his collaborators have discovered a class of dark matter theories with a new dark force that may explain unexpected features seen in the systems across a wide range, from dwarf galaxies to galaxy clusters. More importantly, this new SIDM framework serves as a crutch for particle physicists to convert astronomical data into particle physics parameters of dark matter models. In this way, the SIDM framework is a translator for two different scientific communities to understand each other’s results.

    Now with the PandaX-II experimental collaboration, Yu has shown how self-interacting dark matter theories may be distinguished at the PandaX-II experiment.

    “Prior to this line of work, these types of laboratory-based dark matter experiments primarily focused on dark matter candidates that did not have self-interactions,” Tanedo said. “This work has shown how dark forces affect the laboratory signals of dark matter.”

    Yu noted that this is the first direct detection result for SIDM reported by an experimental collaboration.

    “With more data, we will continue to probe the dark matter interactions with a light mediator and the self-interacting nature of dark matter,” he said.

    Yu was joined in the study by researchers from institutes in China, including Shanghai Jiaotong University, Xinjiang University, Yalong River Hydropower Development Company, Chinese Academy of Sciences, Shangdong University, Tsung-Dao Lee Institute, Peking University, and University of Shanghai for Science and Technology; and from the University of Maryland, College Park, USA. The spokesperson for the PandaX-II collaboration is Xiangdong Ji.

    A grant from the U.S. Department of Energy supported Yu.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

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  • richardmitnick 3:20 pm on December 23, 2017 Permalink | Reply
    Tags: , New lithium-ion battery systems with higher capacities, Researchers Create Next Generation of High-Performance Lithium-Ion Batteries, Silicon is the most promising anode candidate, UC Riverside   

    From UC Riverside: “Researchers Create Next Generation of High-Performance Lithium-Ion Batteries” 

    UC Riverside bloc

    UC Riverside

    December 21, 2017
    Richard Chang
    (951) 827-5893
    rchang@ucr.edu

    1
    Cengiz Ozkan and Mihri Ozkan are developing the next generation of batteries. [Others not named]

    Researchers at the University of California, Riverside’s Bourns College of Engineering have developed a technique to create high performance lithium-ion batteries utilizing sulfur and silicon electrodes. The batteries will extend the range of electric vehicles and plug-in hybrid electric vehicles, while also providing more power with fewer charges to personal electronic devices such as cell phones and laptops.

    The findings were published in an article titled, Advanced Sulfur-Silicon Full Cell Architecture for Lithium Ion Batteries, in the journal, Nature Scientific Reports. Cengiz Ozkan, professor of mechanical engineering, and Mihri Ozkan, professor of electrical and computer engineering, led the project.

    “The demand for renewable energy has pushed the need for higher-performance batteries,” Cengiz Ozkan said.

    As a result, researchers have turned toward new lithium-ion battery systems with higher capacities. Silicon is the most promising anode candidate, storing up to 10 times the capacity of graphite anodes. Sulfur is the most promising cathode candidate, with up to six times the capacity of cathodes. Sulfur-silicon lithium-ion full cells, utilizing silicon as the anode and sulfur as the cathode, are one of the highest-capacity potential systems that have been studied. However, the practice of building sulfur-silicon full cells is challenged by the limitations in materials and equipment.

    “This has limited the amount and extent of research done on the sulfur-silicon full cells, which is why the team proposed and tested a new approach to incorporate lithium into a sulfur-silicon full cell,” Mihri Ozkan said.

    To create the sulfur-silicon full cells (SSFC) with the new architecture, the team added a piece of lithium foil into the traditional full-cell architecture, while enabling contact between the lithium foil and the current collector. This allows the lithium foil to integrate into the system while the battery is being cycled, allowing for control over the amount of lithium inserted.

    “In order to bring together sulfur and silicon electrodes, it is necessary to explore alternative methods of introducing lithium to the system,” said Jeffrey Bell, a UC Riverside graduate student who worked on the project. “We believe that we’ve provided one such solution that will further advance research on sulfur-silicon full cells.”

    “In half cells, pure lithium is used as the anode, which raises safety concerns such as dendrite formation and lithium corrosion. In a full cell, silicon is used as the anode instead, which mitigates the safety issues created by pure lithium anodes, while maintaining the desired high-battery capacity,” added graduate student Rachel Ye.

    This research is the latest in a series of projects led by the Ozkans to create lithium-ion battery materials and architectures from abundant resources and environmentally friendly materials. Previous research has focused on developing and testing anodes from glass bottles, portabella mushrooms, sand, and diatomaceous (fossil-rich) earth.

    In addition to Bell and Ye, other research contributors include graduate students Daisy Patino and Kazi Ahmed. Funding came from UCR and Vantage Advanced Technologies. The university’s Office of Technology Commercialization has filed a patent application for the inventions.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 4:37 pm on October 9, 2017 Permalink | Reply
    Tags: New photodetector, , UC Riverside   

    From UC Riverside: “Prototype Shows How Tiny Photodetectors Can Double Their Efficiency” 

    UC Riverside bloc

    UC Riverside

    October 9, 2017

    Media Contact
    Iqbal Pittalwala
    Tel: (951) 827-6050
    iqbal@ucr.edu
    Twitter: UCR_Sciencenews

    Additional Contacts
    Nathaniel Gabor
    Tel: (951) 827-5338
    nathaniel.gabor@ucr.edu

    Fatemeh Barati
    fbara001@ucr.edu

    Max Grossnickle
    mgros006@ucr.edu

    Physicists at the University of California, Riverside have developed a photodetector – a device that senses light – by combining two distinct inorganic materials and producing quantum mechanical processes that could revolutionize the way solar energy is collected.

    Photodetectors are almost ubiquitous, found in cameras, cell phones, remote controls, solar cells, and even the panels of space shuttles. Measuring just microns across, these tiny devices convert light into electrons, whose subsequent movement generates an electronic signal. Increasing the efficiency of light-to-electricity conversion has been one of the primary aims in photodetector construction since their invention.

    Lab researchers stacked two atomic layers of tungsten diselenide (WSe2) on a single atomic layer of molybdenum diselenide (MoSe2). Such stacking results in properties vastly different from those of the parent layers, allowing for customized electronic engineering at the tiniest possible scale.

    Within atoms, electrons live in states that determine their energy level. When electrons move from one state to another, they either acquire or lose energy. Above a certain energy level, electrons can move freely. An electron moving into a lower energy state can transfer enough energy to knock loose another electron.

    2
    Image shows an energy diagram of the WSe2-MoSe2 device. When a photon (1) strikes the WSe2 layer, it knocks loose an electron (2), freeing it to conduct through the WSe2 (3). At the junction between the two materials, the electron drops down into MoSe2 (4). The energy given off in the drop catapults a second electron from the WSe2 (5) into the MoSe2 (6), where both electrons are free to move and generate electricity. Credit: University Communications, UC Riverside.

    UC Riverside physicists observed that when a photon strikes the WSe2 layer, it knocks loose an electron, freeing it to conduct through the WSe2. At the junction between WSe2 and MoSe2, the electron drops down into MoSe2. The energy given off then catapults a second electron from the WSe2 into the MoSe2, where both electrons become free to move and generate electricity.

    “We are seeing a new phenomenon occurring,” said Nathaniel M. Gabor, an assistant professor of physics, who led the research team. “Normally, when an electron jumps between energy states, it wastes energy. In our experiment, the waste energy instead creates another electron, doubling its efficiency. Understanding such processes, together with improved designs that push beyond the theoretical efficiency limits, will have a broad significance with regard to designing new ultra-efficient photovoltaic devices.”

    Study results appear today in Nature Nanotechnology.

    “The electron in WSe2 that is initially energized by the photon has an energy that is low with respect to WSe2,” said Fatemeh Barati, a graduate student in Gabor’s Quantum Materials Optoelectronics lab and the co-first author of the research paper. “With the application of a small electric field, it transfers to MoSe2, where its energy, with respect to this new material, is high. Meaning, it can now lose energy. This energy is dissipated as kinetic energy that dislodges the additional electron from WSe2.”

    In existing solar panels models, one photon can at most generate one electron. In the prototype the researchers developed, one photon can generate two electrons or more through a process called electron multiplication.

    The researchers explained that in ultrasmall materials, electrons behave like waves. Though it is unintuitive at large scales, the process of generating two electrons from one photon is perfectly allowable at extremely small length scales. When a material, such as WSe2 or MoSe2, gets thinned down to dimensions nearing the electron’s wavelength, the material’s properties begin to change in inexplicable, unpredictable, and mysterious ways.

    3
    UC Riverside’s Nathaniel Gabor (left) is seen here in his Quantum Materials Optoelectronics lab with his graduate students Fatemeh Barati (center) and Max Grossnickle. Photo credit: I. Pittalwala, UC Riverside.

    “It’s like a wave stuck between walls closing in,” Gabor said. “Quantum mechanically, this changes all the scales. The combination of two different ultra small materials gives rise to an entirely new multiplication process. Two plus two equals five.”

    “Ideally, in a solar cell we would want light coming in to turn into several electrons,” said Max Grossnickle, also a graduate student in Gabor’s lab and the research paper’s co-first author. “Our paper shows that this is possible.”

    Barati noted that more electrons could be generated also by increasing the temperature of the device.

    “We saw a doubling of electrons in our device at 340 degrees Kelvin (150 F), which is slightly above room temperature,” she said. “Few materials show this phenomenon around room temperature. As we increase this temperature, we should see more than a doubling of electrons.”

    Electron multiplication in conventional photocell devices typically requires applied voltages of 10-100 volts. To observe the doubling of electrons, the researchers used only 1.2 volts, the typical voltage supplied by an AA battery.

    “Such low voltage operation, and therefore low power consumption, may herald a revolutionary direction in photodetector and solar cell material design,” Grossnickle said.

    He explained that the efficiency of a photovoltaic device is governed by a simple competition: light energy is either converted into waste heat or useful electronic power.

    “Ultrathin materials may tip the balance in this competition by simultaneously limiting heat generation, while increasing electronic power,” he said.

    Gabor explained that the quantum mechanical phenomenon his team observed in their device is similar to what occurs when cosmic rays, coming into contact with the Earth’s atmosphere with high kinetic energy, produce an array of new particles.

    He speculated that the team’s findings could find applications in unforeseen ways.

    “These materials, being only an atom thick, are nearly transparent,” he said. “It’s conceivable that one day we might see them included in paint or in solar cells incorporated into windows. Because these materials are flexible, we can envision their application in wearable photovoltaics, with the materials being integrated into the fabric. We could have, say, a suit that generates power – energy-harvesting technology that would be essentially invisible.”

    Gabor, Barati and Grossnickle were joined in the study by UC Riverside’s Shanshan Su, Roger K. Lake, and Vivek Aji.

    The research was supported by grants from the Air Force Office of Scientific Research, U.S. Department of Energy, a Cottrell Scholar Award, and a National Science Foundation CAREER Award.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 11:00 am on September 27, 2017 Permalink | Reply
    Tags: , , I-Corps-NSF Innovation Corps, National Innovation Network, NSF grant, Prestigious National Science Foundation (NSF) Innovation Corps Site status, The goal is to bridge the gap between public support of science and private capital funding of new commercial ventures, UC Riverside   

    From UC Riverside: “UC Riverside Transformed Into Hub of Innovation with National Science Foundation I-Corp Site Status” 

    UC Riverside bloc

    UC Riverside

    September 26, 2017
    Media Contact
    Richard Chang
    Tel: (951) 827-5893
    E-mail: rchang@ucr.edu

    NSF will also award UC Riverside a $500,000 grant.

    1
    “Startups for Innovators” workshop, taught by Mark Leibowitz and Jay Gilberg, in spring 2017.

    Riverside is poised to become a hub of innovation with a recent grant from the federal government that will help researchers transform their discoveries into real world applications.

    UCR has been awarded the prestigious National Science Foundation (NSF) Innovation Corps Site status and a $500,000 grant to provide in-house commercialization training to UCR faculty and students over the next five years.

    “The goal is to bridge the gap between public support of science and private capital funding of new commercial ventures,” said Rosibel Ochoa, UCR’s associate vice chancellor for technology partnerships. “This award solidifies UC Riverside’s advancement in the innovation and startup creation ecosystem. It provides a platform for ideas originating at the university to receive the training and support needed to promote paths of success for students, faculty and researchers.”

    The NSF Innovation Corps (I-Corps) program prepares scientists and engineers to extend their focus beyond the university laboratory, allowing participants to accelerate research projects toward commercialization. The new award will allow 10 UCR teams per quarter to participate in “Startups for Innovators” workshops, where they will receive NSF I-Corps training on how to interview customers, engage with industry partners and develop ideas into a job-producing business. UCR participants will be eligible to receive up to $3,000 in funding to help develop an idea.

    The NSF I-Corps award allows access to the National Innovation Network, connecting UCR entrepreneurs to a national pipeline of mentors, resources and potential collaborators. This network can provide resources to help form successful startups. Ochoa and her team of entrepreneurs, industry experts and former executives bring over 20 years of combined experience implementing similar innovation and entrepreneurship programs.

    The deadline to apply for the Fall “Startups for Innovators” workshop series at UCR is Oct. 6. An information session for prospective participants will be held at UCR on Oct. 2. Teams who participate in UCR’s “Startups for Innovators” workshops become eligible for selection to the NSF I-Corps National Innovation Network Teams program. According to Ochoa, teams that participate in UCR’s NSF I-Corps programs also have a greater chance of receiving Small Business Innovation Research (SBIR) or Small Business Technology Transfer (STTR) award funding.

    Ochoa believes that the I-Corps Program will pay dividends for the entire Riverside community, “whether it be creating a startup, licensing technology or connecting program participants with local industry partners to support further research and development.”

    In addition to the award, Ochoa’s first year at UCR has seen the launch of the Entrepreneurial Proof of Concept and Innovation Center (EPIC), the expansion of the ExCITE accelerator in conjunction with the city of Riverside and the creation of the $10 million Highlander Venture Fund, which provides seed capital for UCR and Riverside County innovators.

    Co-principal investigators on the grant include Ochoa, Larry Morgan, director of EPIC, and Gillian Wilson, chair of UCR’s Research and Economic Development advisory committee.

    For further information, contact Mark Leibowitz, lead instructor for the UCR NSF I-Corps Startups for Innovators program: Mark.Leibowitz@ucr.edu.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 5:30 pm on September 20, 2017 Permalink | Reply
    Tags: , Chagas disease, Kissing bug, , UC Riverside   

    From UC Riverside: “Scientists Identify New Hosts for Chagas Disease Vectors” 

    UC Riverside bloc

    UC Riverside

    9.20.17
    Sarah Nightingale
    Tel: (951) 827-4580
    E-mail: sarah.nightingale@ucr.edu
    Twitter: @snightingale

    1
    A UCR study is the first to show that tayras, long, slender animals that look similar to weasels, are hosts for parasite-spreading kissing bugs. CC BY 1.0

    Solitary weasel-like animals called tayra might look pretty harmless, but some may actually be incubators for a parasite that causes Chagas disease, a chronic, debilitating condition that is spread by insects called kissing bugs and affects more than 8 million people worldwide. In a study published Monday in the journal PeerJ, researchers from the University of California, Riverside have identified several new hosts for parasite-spreading kissing bug species, including tayras, new world monkeys, sloths, porcupines, and coatis—which are the South American cousins of racoons.

    The research is important because, despite its prevalence, relatively little is known about the transmission of Chagas disease, a deadly, incurable condition that is most common in Latin America.

    “There are 152 species of kissing bug, but we don’t know much about most of them, including the animals they feed on that can act as reservoirs for the parasite. Overall, the existing data is piecemeal, scattered, and biased toward a handful of heavily studied and well-documented species, while little data exists for insects that are found in very secluded habitats,” said Christiane Weirauch, a professor of entomology in UCR’s College of Natural and Agricultural Sciences.

    The UCR study not only increases our knowledge of Chagas disease transmission in rural environments, but also provides the most comprehensive review of animal hosts of the kissing bugs that spread Chagas disease. The research, led by Anna Georgieva, an undergraduate majoring in biology, and Eric Gordon, a graduate student researcher in Weirauch’s lab, will support efforts to control the disease, particularly in poor, rural populations in South America.

    2
    Kissing bugs, like the specimen shown in this image, may be infected with Trypanosoma cruzi, the parasite that causes Chagas disease. No image credit.

    Chagas disease is caused by the parasite Trypanosoma cruzi, which is transmitted to animals and humans by members of the assassin bug subfamily called kissing bugs that feed on blood and are named for their tendency to bite people around the mouth. According to the Centers for Disease Control and Prevention, kissing bugs become infected with T. cruzi by biting an infected animal or person and, once infected, they pass T. cruzi parasites in their feces. When they bite a person and ingest blood, they defecate on them. A person can become infected if bug feces enters their body through mucous membranes or skin lesions caused by the bite wound or scratching. Research also suggests that animals can become infected by eating other animals that harbor the parasite.

    Although Chagas disease is common in rural areas, identifying new hosts among tree-dwelling, and sometimes nocturnal animals is a challenge. To sidestep this problem, the researchers identified new hosts by studying their blood—which they isolated straight from the guts of kissing bugs. The sample included 64 kissing bug samples collected from Central and South America between 2005 and 2015 that were preserved in ethanol.

    “Our modern approach using DNA allowed us to determine this wide variety of animal hosts without a bias towards ones that are already known, unlike some older detection methods” Georgieva said.

    DNA analyses of the ingested blood revealed host associations for 24 of the samples. Among the newly identified hosts was the tayra, which has never before been named as a host for kissing bugs.

    Gordon said the findings will help public health officials develop new methods to control Chagas disease.

    “Education and pesticide application around homes has helped reduce the impact of kissing bugs associated with homes and domestic animals, but now more and more cases of Chagas disease are driven by species most often associated with more rural hosts,” Gordon said.

    “One important consideration in controlling Chagas disease in wild animals is the possibility of bioaccumulation of the parasite in certain carnivores near the top of the food chain. If kissing bugs also feed on these carnivores, as has occurred for the tayra in our study, they are likely to be one of the important links in the transmission chain of the disease in the wild. If a vaccine becomes available one day in the future, they are good candidates to target for immunization to halt the natural spread of the parasite and potentially help to eradicate the pathogen.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 12:55 pm on September 14, 2017 Permalink | Reply
    Tags: , , , , , , Dark matter may have strong self-interactions, Physicists Offer Explanation for Diverse Galaxy Rotations, , UC Riverside   

    From UC Riverside: “Physicists Offer Explanation for Diverse Galaxy Rotations” 

    UC Riverside bloc

    UC Riverside

    September 14, 2017
    Iqbal Pittalwala

    1
    Hai-Bo Yu is an assistant professor of theoretical particle physics and astrophysics at UC Riverside. Photo credit: I. Pittalwala, UC Riverside.

    Identical twins are similar to each other in many ways, but they have different experiences, friends, and lifestyles.

    This concept is played out on a cosmological scale by galaxies. Two galaxies that appear at first glance to be very similar and effectively identical can have inner regions rotating at very different rates – the galactic analog of twins with different lifestyles.

    A team of physicists, led by Hai-Bo Yu of the University of California, Riverside, has found a simple and viable explanation for this diversity.

    Every galaxy sits within a dark matter halo that forms the gravitational scaffolding holding it together.

    Dark matter halo Image credit: Virgo consortium / A. Amblard / ESA

    The distribution of dark matter in this halo can be inferred from the motion of stars and gas particles in the galaxy.

    Yu and colleagues report in Physical Review Letters that diverse galactic-rotation curves, a graph of rotation speeds at different distances from the center, can be naturally explained if dark matter particles are assumed to strongly collide with one another in the inner halo, close to the galaxy’s center – a process called dark matter self-interaction.

    “In the prevailing dark matter theory, called Cold Dark Matter or CDM, dark matter particles are assumed to be collisionless, aside from gravity,” said Yu, an assistant professor of theoretical particle physics and astrophysics, who led the research. “We invoke a different theory, the self-interacting dark matter model or SIDM, to show that dark matter self-interactions thermalize the inner halo, which ties ordinary matter and dark matter distributions together so that they behave like a collective unit. The self-interacting dark matter halo then becomes flexible enough to accommodate the observed diverse rotation curves.”

    Yu explained that the dark matter collisions take place in the dense inner halo, where the luminous galaxy is located. When the particles collide, they exchange energy and thermalize. For low-luminous galaxies, the thermalization process heats up the inner dark matter particles and pushes them out of the central region, reducing the density, analogous to a popcorn machine in which kernels hit each other as they pop, causing them to fly up from the bottom of the machine. For high-luminous galaxies such as the Milky Way, thermalization pulls the particles into the deep potential well of the luminous matter and increases the dark matter density. In addition, the cosmological assembly history of halos also plays a role in generating the observed diversity.

    “Our work demonstrates that dark matter may have strong self-interactions, a radical deviation from the prevailing theory,” Yu said. “It well explains the observed diversity of galactic rotating curves, while being consistent with other cosmological observations.”

    Dark matter makes up about 85 percent of matter in the universe, but its nature remains largely unknown despite its unmistakable gravitational imprint on astronomical and cosmological observations. The conventional way to study dark matter is to assume that it has some additional, nongravitational interaction with visible matter that can be studied in the lab. Physicists do not know, however, if such an interaction between dark and visible matter even exists.

    Over the last decade, Yu has pioneered a new line of research based on the following premise: Setting aside whether dark matter interacts with visible matter, what happens if dark matter interacts with itself through some new dark force?

    Yu posited the new dark force would affect the dark matter distribution in each galaxy’s halo. He realized that there is indeed a discrepancy between CDM and astronomical observations that could be solved if dark matter is self-interacting.

    “The compatibility of this hypothesis with observations is a major advance in the field,” said Flip Tanedo, an assistant professor of theoretical particle physics at UC Riverside, who was not involved in the research. “The SIDM paradigm is a bridge between fundamental particle physics and observational astronomy. The consistency with observations is a big hint that this proposal has a chance of being correct and lays the foundation for future observational, experimental, numerical, and theoretical work. In this way, it is paving the way to new interdisciplinary research.”

    SIDM was first proposed in 2000 by a pair of eminent astrophysicists. It experienced a revival in the particle physics community around 2009, aided in part by key work by Yu and collaborators.

    “This is a special time for this type of research because numerical simulations of galaxies are finally approaching a precision where they can make concrete predictions to compare the observational predictions of the self-interacting versus cold dark matter scenarios,” Tanedo said. “In this way, Hai-Bo is the architect of modern self-interacting dark matter and how it merges multiple different fields: theoretical high-energy physics, experimental high-energy physics, observational astronomy, numerical simulations of astrophysics, and early universe cosmology and galaxy formation.”

    The research paper is included by Physical Review Letters as a “Editor’s Suggestion” and featured also in APS Physics.

    Yu was joined in the research by Ayuki Kamada, a postdoctoral researcher at UCR; and UC Irvine’s Manoj Kaplinghat and Andrew B. Pace.

    Yu’s research was supported by grants from the U.S. Department of Energy and the Hellman Fellows Fund. The National Science Foundation provided the research team with additional funding.

    See the full article here .

    [This article would have been helped with examples of galaxies.

    Please help promote STEM in your local schools.

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    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 2:52 pm on July 27, 2017 Permalink | Reply
    Tags: , , , , , , SpARCS collaboration, UC Riverside   

    From Keck: “Scientists Get Best Measure of Star-Forming Material in Galaxy Clusters in Early Universe” 

    Keck Observatory

    Keck Observatory.
    Keck, with Subaru and IRTF (NASA Infrared Telescope Facility). Vadim Kurland

    Keck Observatory

    Previously covered from Uc Riverside, https://sciencesprings.wordpress.com/2017/07/20/from-uc-riverside-scientists-get-best-measure-of-star-forming-material-in-galaxy-clusters-in-early-universe/. But Keck deserves its own story.

    July 26, 2017

    Mari-Ela Chock, Communications Officer
    W. M. Keck Observatory
    mchock@keck.hawaii.edu
    (808) 554-0567

    The international Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) collaboration based at the University of California, Riverside has combined observations from several of the world’s most powerful telescopes, including W. M. Keck Observatory on Maunakea, Hawaii, to carry out one of the largest studies yet of molecular gas – the raw material which fuels star formation throughout the universe – in three of the most distant clusters of galaxies ever found, detected as they appeared when the universe was only four billion years old. Allison Noble, a postdoctoral researcher at the Massachusetts Institute of Technology, led this newest research from the SpARCS collaboration.

    SpARCS collaboration
    5
    To date, we have spectroscopically confirmed about a dozen z > 1 clusters. Above are three examples of rich clusters which SpARCS has discovered.

    Results were recently published in The Astrophysical Journal Letters.

    2
    The Tadpole Galaxy is a disrupted spiral galaxy showing streams of gas stripped by gravitational interaction with another galaxy. Molecular gas is the required ingredient to form stars in galaxies in the early universe. Credit: HUBBLE LEGACY ARCHIVE, ESA, NASA AND BILL SNYDER.

    Clusters are rare regions of the universe consisting of tight groups of hundreds of galaxies containing trillions of stars, as well as hot gas and mysterious dark matter.

    First, the research team used spectroscopic observations from the Very Large Telescope in Chile and Keck Observatory’s powerful Multi-Object Spectrograph for Infrared Exploration (MOSFIRE) to confirm nearly a dozen galaxies were star-forming members of the three massive clusters.

    ESO/VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    Keck/MOSFIRE on Keck 1, Mauna Kea, Hawaii, USA

    “Keck Observatory’s MOSFIRE data were essential to proving conclusively that the 11 galaxies analyzed (two pairs) were indeed members of the three clusters and not foreground galaxies,” said Gillian Wilson, a professor of physics and astronomy at UC Riverside and the leader of the SpARCS collaboration.

    Next, the researchers took images through multiple filters from NASA’s Hubble Space Telescope, which revealed a surprising diversity in the galaxies’ appearance, with some galaxies having already formed large disks with spiral arms.

    NASA/ESA Hubble Telescope

    One of the telescopes the SpARCS scientists used is the extremely sensitive Atacama Large Millimeter Array (ALMA) telescope capable of directly detecting radio waves emitted from the molecular gas found in galaxies in the early universe.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ALMA observations allowed the scientists to determine the amount of molecular gas in each galaxy, and provided the best measurement yet of how much fuel was available to form stars.

    The researchers compared the properties of galaxies in these clusters with the properties of “field galaxies” (galaxies found in more typical environments with fewer close neighbors). To their surprise, they discovered that cluster galaxies had higher amounts of molecular gas relative to the amount of stars in the galaxy compared to field galaxies. The finding puzzled the team because it has long been known that when a galaxy falls into a cluster, interactions with other cluster galaxies and hot gas accelerate the shut off of its star formation relative to that of a similar field galaxy (the process is known as environmental quenching).

    “This is definitely an intriguing result,” said Wilson. “If cluster galaxies have more fuel available to them, you might expect them to be forming more stars than field galaxies, and yet they are not.”

    Allison Noble, a SpARCS collaborator and this study’s leader, suggests several possible explanations: It is possible that something about being in the hot, harsh cluster environment surrounded by many neighboring galaxies perturbs the molecular gas in cluster galaxies such that a smaller fraction of that gas actively forms stars. Alternatively, it is possible that an environmental process, such as increased merging activity in cluster galaxies, results in the observed differences between the cluster and field galaxy populations.

    “While the current study does not answer the question of which physical process is primarily responsible for causing the higher amounts of molecular gas, it provides the most accurate measurement yet of how much molecular gas exists in galaxies in clusters in the early universe,” Wilson said.

    The SpARCS team has developed new techniques using infrared observations from NASA’s Spitzer Space Telescope to identify hundreds of previously undiscovered clusters of galaxies in the early universe.

    NASA/Spitzer Infrared Telescope

    In the future, they plan to study a larger sample of clusters. The team has recently been awarded additional time on ALMA, Keck Observatory, and the Hubble Space Telescope to continue investigating how the neighborhood in which a galaxy lives determines for how long it can form stars.

    The Keck Observatory data were obtained as the result of a collaboration amongst Wilson and fellow UC faculty members Michael Cooper (UC Irvine) and Saul Perlmutter (UC Berkeley).

    About MOSFIRE

    The Multi-Object Spectrograph for Infrared Exploration (MOSFIRE), gathers thousands of spectra from objects spanning a variety of distances, environments and physical conditions. What makes this large, vacuum-cryogenic instrument unique is its ability to select up to 46 individual objects in the field of view and then record the infrared spectrum of all 46 objects simultaneously. When a new field is selected, a robotic mechanism inside the vacuum chamber reconfigures the distribution of tiny slits in the focal plane in under six minutes. Eight years in the making with First Light in 2012, MOSFIRE’s early performance results range from the discovery of ultra-cool, nearby substellar mass objects, to the detection of oxygen in young galaxies only two billion years after the Big Bang. MOSFIRE was made possible by funding generously provided by the National Science Foundation and astronomy benefactors Gordon and Betty Moore. It is currently the most in-demand instrument at Keck Observatory.

    Other Authors

    Michael McDonald, Massachusetts Institute of Technology
    Adam Muzzin, York University, Canada
    Julie Nantais, Universidad Andres Bello, Chile
    Gregory Rudnick, University of Kansas
    Eelco van Kampen, European Southern Observatory, Germany
    Tracy Webb, McGill University, Canada
    Howard K.C. Yee, University of Toronto, Canada
    Kyle Boone, UC Berkeley
    Andrew DeGroot, UC Riverside
    Anna Delahaye, McGill University, Canada
    Ricardo Demarco, Universidad de Concepción, Chile
    Ryan Foltz, UC Riverside
    Brian Hayden, UC Berkeley/Lawrence Berkeley National Laboratory
    Chris Lidman, Australian Astronomical Observatory
    Ariadna Manilla-Robles, European Southern Observatory, Germany

    See the full article here .

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    Mission
    To advance the frontiers of astronomy and share our discoveries with the world.

    The W. M. Keck Observatory operates the largest, most scientifically productive telescopes on Earth. The two, 10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrometer and world-leading laser guide star adaptive optics systems. Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

    Today Keck Observatory is supported by both public funding sources and private philanthropy. As a 501(c)3, the organization is managed by the California Association for Research in Astronomy (CARA), whose Board of Directors includes representatives from the California Institute of Technology and the University of California, with liaisons to the board from NASA and the Keck Foundation.
    Keck UCal

     
  • richardmitnick 1:31 pm on July 20, 2017 Permalink | Reply
    Tags: , , , Cluster galaxies, , field galaxies, , SpARCS-Spitzer Adaptation of the Red-sequence Cluster Survey, UC Riverside   

    From UC Riverside: “Scientists Get Best Measure of Star-forming Material in Galaxy Clusters in Early Universe” 

    UC Riverside bloc

    UC Riverside

    July 20, 2017
    Iqbal Pittalwala

    1
    The Tadpole Galaxy is a disrupted spiral galaxy showing streams of gas stripped by gravitational interaction with another galaxy. Molecular gas is the required ingredient to form stars in galaxies in the early universe. Credit: Hubble Legacy Archive, ESA, NASA and Bill Snyder.

    The international Spitzer Adaptation of the Red-sequence Cluster Survey (SpARCS) collaboration based at the University of California, Riverside has combined observations from several of the world’s most powerful telescopes to carry out one of the largest studies yet of molecular gas – the raw material which fuels star formation throughout the universe – in three of the most distant clusters of galaxies ever found, detected as they appeared when the universe was only four billion years old.

    Results were recently published in The Astrophysical Journal Letters. Allison Noble, a postdoctoral researcher at the Massachusetts Institute of Technology, led this newest research from the SpARCS collaboration.

    Clusters are rare regions of the universe consisting of tight groups of hundreds of galaxies containing trillions of stars, as well as hot gas and mysterious dark matter. First, the research team used spectroscopic observations from the W. M. Keck Observatory on Maunakea, Hawai’i, and the Very Large Telescope in Chile that confirmed 11 galaxies were star-forming members of the three massive clusters.


    Keck Observatory, Maunakea, Hawaii, USA

    ESO/VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

    Next, the researchers took images through multiple filters from NASA’s Hubble Space Telescope, which revealed a surprising diversity in the galaxies’ appearance, with some galaxies having already formed large disks with spiral arms.

    NASA/ESA Hubble Telescope

    One of the telescopes the SpARCS scientists used is the extremely sensitive Atacama Large Millimeter Array (ALMA) telescope capable of directly detecting radio waves emitted from the molecular gas found in galaxies in the early universe.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    ALMA observations allowed the scientists to determine the amount of molecular gas in each galaxy, and provided the best measurement yet of how much fuel was available to form stars.

    The researchers compared the properties of galaxies in these clusters with the properties of “field galaxies” (galaxies found in more typical environments with fewer close neighbors). To their surprise, they discovered that cluster galaxies had higher amounts of molecular gas relative to the amount of stars in the galaxy, compared to field galaxies. The finding puzzled the team because it has long been known that when a galaxy falls into a cluster, interactions with other cluster galaxies and hot gas accelerate the shut off of its star formation relative to that of a similar field galaxy (the process is known as environmental quenching).

    “This is definitely an intriguing result,” said Gillian Wilson, a professor of physics and astronomy at UC Riverside and the leader of the SpARCS collaboration. “If cluster galaxies have more fuel available to them, you might expect them to be forming more stars than field galaxies, and yet they are not.”

    Noble, a SpARCS collaborator and the study’s leader, suggests several possible explanations: It is possible that something about being in the hot, harsh cluster environment surrounded by many neighboring galaxies perturbs the molecular gas in cluster galaxies such that a smaller fraction of that gas actively forms stars. Alternatively, it is possible that an environmental process, such as increased merging activity in cluster galaxies, results in the observed differences between the cluster and field galaxy populations.

    “While the current study does not answer the question of which physical process is primarily responsible for causing the higher amounts of molecular gas, it provides the most accurate measurement yet of how much molecular gas exists in galaxies in clusters in the early universe,” Wilson said.

    The SpARCS team has developed new techniques using infrared observations from NASA’s Spitzer Space Telescope to identify hundreds of previously undiscovered clusters of galaxies in the early universe.

    NASA/Spitzer Telescope

    In the future, they plan to study a larger sample of clusters. The team has recently been awarded additional time on ALMA, the W. M. Keck Observatory, and the Hubble Space Telescope to continue investigating how the neighborhood in which a galaxy lives determines for how long it can form stars.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 8:39 am on July 14, 2017 Permalink | Reply
    Tags: , , Slow Earthquakes Occur Continuously in the Alaska-Aleutian Subduction Zone, UC Riverside   

    From UC Riverside: “Slow Earthquakes Occur Continuously in the Alaska-Aleutian Subduction Zone” 

    UC Riverside bloc

    UC Riverside

    July 12, 2017
    Iqbal Pittalwala

    1
    Image shows tremor sources and low frequency earthquake distribution in the study region and historic large earthquakes in the Alaska-Aleutian subduction zone. Each red star represents the location of 1 min tremor signal determined by the beam back projection method, and the black stars show three visually detected low frequency earthquakes located using arrival times of body waves. Image credit: Ghosh lab, UC Riverside.

    Seismologists at the University of California, Riverside studying earthquakes in the seismically and volcanically active Alaska-Aleutian subduction zone have found that “slow earthquakes” are occurring continuously, and could encourage damaging earthquakes.

    Slow earthquakes are quiet, can be as large as magnitude 7, and last days to years. Taking place mainly at the boundary between tectonic plates, they happen so slowly that people don’t feel them. A large slow earthquake is typically associated with abundant seismic tremor—a continuous weak seismic chatter—and low frequency (small and repeating) earthquakes.

    “In the Alaska-Aleutian subduction zone, we found seismic tremor, and visually identified three low frequency earthquakes,” said Abhijit Ghosh, an assistant professor of Earth sciences, who led the research published recently in Geophysical Research Letters. “Using them as templates, we detected nearly 1,300 additional low frequency earthquakes. Slow earthquakes may play an important role in the earthquake cycles in this subduction zone.”

    The Alaska-Aleutian subduction zone, which stretches from the Gulf of Alaska to the Kamchatka Peninsula in the Russian Far East, is one of the most active plate boundaries in the world. It is 3,800 km long and forms the plate boundary between the Pacific and North American plates. In the last 80 years, four massive earthquakes (greater than magnitude 8) have occurred here.

    2
    Abhijit Ghosh lands in Alaska to do field work. Photo credit: Ghosh lab, UC Riverside.

    Ghosh explained that tectonic tremor—which causes a weak vibration of the ground—and low frequency earthquakes are poorly studied in the Alaska-Aleutian subduction zone due to limited data availability, difficult logistics, and rugged terrain.

    But using two months of high-quality continuous seismic data recorded from early July-September 2012 at 11 stations in the Akutan Island, Ghosh and his graduate student, Bo Li, detected near-continuous tremor activity with an average of 1.3 hours of tectonic tremor per day using a “beam back projection” method—an innovative array-based method Ghosh developed to automatically detect and locate seismic tremor. Using the seismic arrays the method continuously scans the subsurface for any seismic activity. Just like a radar antenna, it determines from which direction the seismic signal originates and uses that information to locate it. Practically, it can track slow earthquakes minute-by-minute.

    Ghosh and Li found that tremor sources were clustered in two patches with a nearly 25 km gap in between them, possibly indicating that frictional properties determining earthquake activities change laterally along this area. Ghosh explained that this gap impacts the region’s overall stress pattern and can affect earthquake activity nearby.

    “In addition, slow earthquakes seem to have ‘sweet spots’ along the subduction fault that produces majority of the tremor activity,” he said. “We found that the western patch has a larger depth range and shows higher tremor source propagation velocities. More frequent tremor events and low frequency earthquakes in the western patch may be a result of higher fluid activity in the region and indicate a higher seismic slip rate than the eastern region.”

    Ghosh, Li, and their collaborators in multiple institutions in the United States have taken the next step by installing three additional seismic arrays in a nearby island to simultaneously image the subduction fault and volcanic system.

    “This ambitious experiment will provide new insights into the seismic activity and subduction processes in this region,” Ghosh said.

    The study [Geophysical Reseach Letters] was supported by grants to Ghosh from the National Science Foundation-Division of Earth Sciences, EarthScope, the United States Geological Survey, and the Alaska Volcano Observatory.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
  • richardmitnick 7:39 am on June 29, 2017 Permalink | Reply
    Tags: , , It often goes undetected until it has spread within the pelvis and abdomen by which point it is difficult to treat and usually fatal, MCAs- Multicellular aggregates, , Ovarian cancer, UC Riverside,   

    From UC Riverside: “Study Sheds Light on How Ovarian Cancer Spreads” 

    UC Riverside bloc

    UC Riverside

    June 26, 2017
    Sarah Nightingale

    1
    Researchers at UC Riverside and Notre Dame used fluorescently-tagged cells to study the molecular mechanisms of metastasis in ovarian cancer. No image credit.

    With 20,000 diagnoses each year, ovarian cancer is the ninth most common cancer and fifth leading cause of cancer death among women in the United States. So many women die from ovarian cancer because it often goes undetected until it has spread within the pelvis and abdomen, by which point it is difficult to treat and usually fatal.

    A team of researchers from the University of California, Riverside and the University of Notre Dame are studying the molecular mechanisms by which ovarian cancer spreads—or metastasizes—to uncover new therapeutic opportunities.

    In their latest paper, published in the journal Oncogene, they used live imaging and electron microscopy to study the cellular activities associated with successful metastasis, including the expression of a group of proteins called cadherins, which help cells bind together. Since these proteins enable cancer cells to anchor to new sites in the body, it may be possible to disrupt metastasis by blocking cadherin-mediated binding. The research was led by Mark Alber, a distinguished professor of applied mathematics at UC Riverside, and M. Sharon Stack, a Kleiderer-Pezold professor of biochemistry and director of Notre Dame Harper Cancer Research Institute.

    As primary ovarian tumors metastasize, they shed both single cells and clusters of cells, called multicellular aggregates (MCAs), into the pelvis and abdomen. To study exactly how metastasis occurs, the researchers quantified the interactions between epithelial ovarian cancer (EOC) cells and three-dimensional models of the abdomen wall. They showed when EOC cells acquired (MCAs)(Ncad), an event that occurs in human EOC tumors, they could penetrate and attach to the abdomen wall. Furthermore, MCAs dispersed prior to invasion as a large cohort of cells, showing that cell to cell junctional integrity (i.e. attachment at the single cell level) was needed for successful metastasis.

    Alber said unlike results observed in other cancers, ovarian cancer cells do not appear to exhibit a ‘leader-follower’ type of collective cell invasion.

    “Interestingly, co-culture of Ncad-expressing cells with cells expressing E-cadherin (Ecad) did not promote invasion of the Ecad-expressing cells, demonstrating that Ncad-expressing cells do not simply lead the way for other cell populations to follow,” Stack said.

    The findings emphasize the importance of Ncad in ovarian cancer metastasis and provide the rationale to support pre-clinical studies using Ncad-blocking molecules as a therapeutic strategy to suppress EOC metastatic anchoring.

    The group is using these results to develop computational models of cancer cell invasion. Future studies will also use patient samples, which will be provided by collaborators from the City of Hope, in Duarte, Calif. for combined modeling and experimental approaches to obtain novel insights into the cellular mechanisms of ovarian cancer metastasis.

    The title of the Oncogene paper is Cadherin composition and multicellular aggregate invasion in organotypic models of epithelial ovarian cancer intraperitoneal metastasis (published online: http://rdcu.be/tyCF). In addition to Alber and Stack, contributors include assistant research scientist Oleg Kim at UC Riverside, and Yuliya Klymenko, Elizabeth Loughran, Jing Yang and Rachel Lombard, who are all at Notre Dame.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    UC Riverside Campus

    The University of California, Riverside is one of 10 universities within the prestigious University of California system, and the only UC located in Inland Southern California.

    Widely recognized as one of the most ethnically diverse research universities in the nation, UCR’s current enrollment is more than 21,000 students, with a goal of 25,000 students by 2020. The campus is in the midst of a tremendous growth spurt with new and remodeled facilities coming on-line on a regular basis.

    We are located approximately 50 miles east of downtown Los Angeles. UCR is also within easy driving distance of dozens of major cultural and recreational sites, as well as desert, mountain and coastal destinations.

     
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