Small Galaxies Reionize (Astronomy)

A study conducted by a team of astrophysicists from the University of Minnesota (USA) shows that high-energy light from small galaxies may have played a key role in the evolution of the Universe. We talk about it with Claudia Scarlata, professor at the University of Minnesota and co-author of the study

The first billion years of the universe’s history can be described as a succession of periods of dark and periods of light: in particular, there was a phase in which it was opaque to radiation, followed by an age in which it is become more and more transparent. It is the so-called epoch of reionization : the period in which the primordial gas that pervaded the universe in bands – essentially made up of hydrogen atoms – begins to pass from the neutral state to the ionized plasma state. It is the beginning of the end of the previous epoch of darkness, the dark age , in fact, and the prelude to the phase of light in which we still find ourselves.

Schematic view of the main stages of the Big Bang. Credits: National Astronomical Observatory of Japan (Naoj)

During the era of reionization, the mass of neutral hydrogen has gradually decreased, thus allowing photons to move more and more freely, to the point where almost all cosmic gas is ionized and the universe is completely transparent to light. of distant stars and galaxies. How this happened is not entirely clear, however. It is not clear, above all, the origin of the high-energy photons that converted the opaque and electrically neutral gas into ionized plasma. Indirect evidence and theoretical studies suggest that these are the photons emitted by the stars in formation within the first generations of galaxies, which in the meantime had formed from the gas densification due to gravity. In this hypothesis, however, there is a problem: the galaxies in turn contain clouds of hydrogen which absorb light, just like clouds in the earth’s atmosphere absorb sunlight on a cloudy day. This should have prevented the photons from escaping – and thus from ionizing the surrounding intergalactic gas.

One possibility to solve this problem is to hypothesize the existence of a population of primordial galaxies without hydrogen clouds inside them. To date, however, no evidence of similar galaxies has ever been found. Until today, in fact. Using data from the Gemini South telescope , a team of astrophysicists from the University of Minnesota seems to have now managed to find one.

Its name is Pox 186 : a small dwarf galaxy in the Virgo constellation , about 68 million light years from Earth, where the hydrogen clouds appear to have been completely removed. It could therefore be a galaxy similar to those present at the time of re-ionization, whose high-energy light, not absorbed by any internal gas, would have reionized the intergalactic gas.

To find out more Media Inaf reached out to one of the authors of the publication that reports the details of the discovery, the astrophysicist Claudia Scarlata. Born in Cagliari, after graduating in astronomy and a doctorate at the University of Padua, she worked for several years as a postdoctoral scholar at Eth in Zurich and at Caltech. In 2011 she became a lecturer in the School of Physics and Astronomy of the University of Minnesota, where she is also the director of the doctoral course. In 2019 he received the George W. Taylor Award for Distinguished Research from the same University .

Professor Scarlata, how did the idea behind the work that led to this discovery come about?

“One of the main problems of modern astrophysics is understanding how most of the hydrogen in the universe went from completely neutral to ionized (a transformation that is called reionization). To ionize the universe, photons more energetic than 13.6eV produced by very young stars need to be able to reach the hydrogen of the intergalactic medium, without being absorbed by the gas and dust – typically associated with younger stars. The problem is to identify the galaxies from which these photons “flee”. Pox 186 is a very small galaxy in the local universe, known for having no neutral hydrogen (or having so little of it that it cannot be measured) and for the fact that it is actively forming new stars.

 What survey technique did you use?

« Full-field spectroscopy , using the Gemini 8-meter telescope together with the Gmos spectrograph . This observational technique allows to obtain spectra in every position within the galaxy and therefore to have a much more detailed idea (compared to simple images) of the physical conditions of the gas and of the stars ».

Claudia Scarlata, professor at the University of Minnesota, co-author of the study published in The Astrophysical Journal

Why did  you focus on this galaxy?

“Pox 186 is a special galaxy for various reasons. First of all, it has some physical characteristics that make it very similar to the galaxies we think were present in the early universe, during reionization. Pox 186, however, is very close to us (in what we call the local universe) and this allows us to perform measurements that are not yet realistically possible in distant galaxies (we will have to wait until Jwst). In essence, Pox 186 is a perfect laboratory to test various hypotheses on the physical processes that can affect reionization. Also, as I said earlier, Pox 186 is famous for not having neutral hydrogen, or having so little of it that it cannot be measured. This fact is important because typically the formation of new stars is associated with the presence of neutral gas and a lot of dust ».

What are the possible physical mechanisms that in your opinion have caused this galaxy to empty its gas content, bringing it into a state you call blow-away ?

“Here I would like to quote the words of my student, Nathan Eggen , first author of the study. “One can imagine that the energy released in a star formation episode pushes gas from a galaxy like a balloon is inflating. However, if the star formation is too intense, there is the possibility that the surface of the balloon will pierce, allowing a portion of this energy to escape. In the case of Pox 186, the star formation was so intense that it destroyed the balloon completely, and thus the gas was removed completely, blown-away . The energy for this process is therefore associated with the star formation process. In particular, the energy associated with the explosion of young and massive stars such as supernovae and with istellar winds ».

What conclusions can be drawn from this study?

 What we have found is that in Pox186 some of the gas is moving at such a high speed that the gravitational pull of the galaxy is not enough to hold it back. This study confirms that it is possible to completely remove the gas from small galaxies, through “purely internal” mechanisms, that is, associated only with the galaxy itself and not with interactions with the environment. This kind of feedbackit is predicted by virtually all modern numerical simulations, but had not yet been confirmed experimentally. Consequently, our study suggests that very young galaxies in the distant universe may have gone through a phase where the lack of neutral gas has allowed ionizing radiation to escape from these objects, facilitating reionization. ‘

Problem of reionization solved?

«Solved no. But certainly our work allows us to better understand what kind of galaxies have contributed considerably to the process ».

How could confirmation of the involvement of this type of galaxies in the reionization of the universe be obtained ?

“From Earth, until the next generation of telescopes (like the European Extremely Large Telescope) arrives, it will be quite difficult to greatly increase what we already know about the first galaxies. Let’s say we are reaching the limits of what can be done with the technology we have. Fortunately, at the end of the year (in October) the James Webb Space Telescope will be launched , which will revolutionize our knowledge of galaxies in the distant universe ».

Do you already have a “sequel” to this study in mind?

“We are getting images and spectra of Pox 186 with the Hubble Space Telescope. The Hubble telescope allows us to observe in ultraviolet, where most of the energy produced in young stars is found. These data will allow us to better understand what is happening in nearby galaxies and therefore to interpret the observations of distant galaxies that Jwst will soon obtain ».

Featured image: The study by a team of astronomers led by the University of Minnesota suggests that high-energy light from small galaxies, such as the Galaxy Pox 186 pictured here, may have played a key role in the reionization and evolution of the universe. Credits: Podevin, Jf, 2006


To know more:


Provided by INAF

HEPA filter reduces airborne respiratory particles generated during exercise that can transmit viruses (Physiology)

A pair of Mayo Clinic studies shed light on something that is typically difficult to see with the eye: respiratory aerosols. Such aerosol particles of varying sizes are a common component of breath, and they are a typical mode of transmission for respiratory viruses like COVID-19 to spread to other people and surfaces.

Researchers who conduct exercise stress tests for heart patients at Mayo Clinic found that exercising at increasing levels of exertion increased the aerosol concentration in the surrounding room. Then also found that a high-efficiency particulate air (HEPA) device effectively filtered out the aerosols and decreased the time needed to clear the air between patients.

“Our work was conducted with the support of Mayo Cardiovascular Medicine leadership who recognized right at the start of the pandemic that special measures would be required to protect patients and staff from COVID-19 while continuing to provide quality cardiovascular care to all who needed it,” says Thomas Allison, Ph.D., director of Cardiopulmonary Exercise Testing at Mayo Clinic in Rochester. “Since there was no reliable guidance on how to do this, we put a research team together to find answers through scientific testing and data. We are happy to now share our findings with everyone around the world.” Dr. Allison is senior author of both studies.

To characterize the aerosols generated during various intensities of exercise in the first study, Dr. Allison’s team set up a special aerosol laboratory in a plastic tent with controlled airflow. Two types of laser beam particle counters were used to measure aerosol concentration at the front, back and sides of a person riding an exercise bike. Eight exercise volunteers wore equipment to measure their oxygen consumption, ventilation and heart rate.

During testing, a volunteer first had five minutes of resting breathing, followed by four bouts of three-minute exercise staged ― with monitoring and coaching ― to work at 25%, 50%, 75% and 100% of their age-predicted heart rate. This effort was followed by three minutes of cooldown. The findings are publicized online in CHEST.

The aerosol concentrations increased exponentially throughout the test. Specifically, exercise at or above 50% of resting heart rate showed significant increases in aerosol concentration.

“In a real sense, I think we have proven dramatically what many suspected ― that is why gyms were shut down and most exercise testing laboratories closed their practices. Exercise testing was not listed as an aerosol-generating procedure prior to our studies because no one had specifically studied it before. Exercise generates millions of respiratory aerosols during a test, many of a size reported to have virus-carrying potential. The higher the exercise intensity, the more aerosols are produced,” says Dr. Allison.

The follow-up study led by Dr. Allison focused on how to mitigate the aerosols generated during exercise testing by filtering them out of the air immediately after they came out of the subject’s mouth. Researchers used a similar setup with the controlled airflow exercise tent, particle counter and stationary bike, but added a portable HEPA filter with a flume hood.

Six healthy volunteers completed the same 20-minute exercise test as the previous study, first without the mitigation and then with the portable HEPA filter running.

Also, a separate experiment tested aerosol clearance time in the clinical exercise testing laboratories by using artificially generated aerosols to test how long it took for 99.9% of aerosols to be removed. Researchers performed the test first with only existing heating, ventilation and air conditioning, and then with the addition of the portable HEPA filter running.

“Studying clearance time informed us of how soon we could safely bring a new patient into the laboratory after finishing the test on the previous patient. HEPA filters cut this time by 50%, allowing the higher volume of testing necessary to meet the clinical demands of our Cardiovascular Medicine practice,” says Dr. Allison.

“We translated CDC (Centers for Disease Control and Prevention) guidelines for aerosol mitigation with enhanced airflow through HEPA filters and showed that it worked amazingly well for exercise testing. We found that 96% plus or minus 2% of aerosols of all sizes generated during heavy exercise were removed from the air by the HEPA filter. As a result, we have been able to return to our practice of performing up to 100 stress tests per day without any recorded transmission of COVID in our exercise testing laboratories,” says Dr. Allison.

Reference: Sajgalik, Pavol et al., “Characterization of Aerosol Generation during Various Intensities of Exercise”, Chest, 2021. DOI: https://doi.org/10.1016/j.chest.2021.04.041


Provided by Mayo Clinic


About Mayo Clinic

Mayo Clinic is a nonprofit organization committed to innovation in clinical practice, education and research, and providing compassion, expertise and answers to everyone who needs healing. Visit the Mayo Clinic News Network for additional Mayo Clinic news. For information on COVID-19, including Mayo Clinic’s Coronavirus Map tracking tool, which has 14-day forecasting on COVID-19 trends, visit the Mayo Clinic COVID-19 Resource Center.

Researchers Develop New Graphite-based Sensor Technology for Wearable Medical Devices (Medicine)

Researchers at AMBER, the SFI Centre for Advanced Materials and BioEngineering Research, and from Trinity’s School of Physics, have developed next-generation, graphene-based sensing technology using their innovative G-Putty material.

The team’s printed sensors are 50 times more sensitive than the industry standard and outperform other comparable nano-enabled sensors in an important metric seen as a game-changer in the industry: flexibility.

Maximising sensitivity and flexibility without reducing performance makes the teams’ technology an ideal candidate for the emerging areas of wearable electronics and medical diagnostic devices.

The team – led by Professor Jonathan Coleman from Trinity’s School of Physics, one of the world’s leading nanoscientists – demonstrated that they can produce a low-cost, printed, graphene nanocomposite strain sensor.

Creating and testing inks of different viscosities (runniness) the team found that they could tailor G-Putty inks according to printing technology and application.

They published their results in the journal Small.

In medical settings, strain sensors are a highly valuable diagnostic tool used to measure changes in mechanical strain such as pulse rate, or the changes in a stroke victim’s ability to swallow. A strain sensor works by detecting this mechanical change and converting it into a proportional electrical signal, thereby acting as mechanical-electrical converter.

While strain sensors are currently available on the market they are mostly made from metal foil that poses limitations in terms wearability, versatility, and sensitivity.

Professor Coleman said: 

“My team and I have previously created nanocomposites of graphene with polymers like those found in rubberbands and silly putty. We have now turned G-putty, our highly malleable graphene blended silly putty, into an ink blend that has excellent mechanical and electrical properties. Our inks have the advantage that they can be turned into a working device using industrial printing methods, from screen printing, to aerosol and mechanical deposition.

“An additional benefit of our very low cost system is that we can control a variety of different parameters during the manufacturing process, which gives us the ability to tune the sensitivity of our material for specific applications calling for detection of really minute strains.”

Current market trends in the global medical device market indicate that this research is well placed within the move to personalised, tuneable, wearable sensors that can easily be incorporated into clothing or worn on skin.

In 2020 the wearable medical device market was valued at USD $16 billion with expectations for significant growth particularly in remote patient monitoring devices and an increasing focus on fitness and lifestyle monitoring.

The team is ambitious in translating the scientific work into product. Dr Daniel O’Driscoll, Trinity’s School of Physics, added: 

“The development of these sensors represents a considerable step forward for the area of wearable diagnostic devices – devices which can be printed in custom patterns and comfortably mounted to a patient’s skin to monitor a range of different biological processes.

“We’re currently exploring applications to monitor real-time breathing and pulse, joint motion and gait, and early labour in pregnancy. Because our sensors combine high sensitivity, stability and a large sensing range with the ability to print bespoke patterns onto flexible, wearable substrates, we can tailor the sensor to the application. The methods used to produce these devices are low cost and easily scalable – essential criteria for producing a diagnostic device for wide scale use.”

Professor Coleman was recently awarded a European Research Council Proof of Concept grant to build on these results to begin to develop a prototype for a commercial product. The ultimate aim of the group is identify potential investors and industry partners, and form a spin-out around the technology focusing on both recreational and medical applications.

Featured image: The team developed a method to formulate G?putty?based inks that can be printed as a thin-film onto elastic substrates, including band-aids, and attached easily to the skin. © TCD


Reference: O’Driscoll, D. P., McMahon, S., Garcia, J., Biccai, S., Gabbett, C., Kelly, A. G., Barwich, S., Moebius, M., Boland, C. S., Coleman, J. N., Printable G‐Putty for Frequency‐ and Rate‐Independent, High‐Performance Strain Sensors. Small 2021, 2006542. https://doi.org/10.1002/smll.202006542


Provided by Trinity College Dublin

Hopkins-Led Research Team Takes Gene Mutation Detection in Blood to the Next Level (Medicine)

Next-generation gene sequencing (NGS) technologies —in which millions of DNA molecules are simultaneously but individually analyzed— theoretically provides researchers and clinicians the ability to noninvasively identify mutations in the blood stream. Identifying such mutations enables earlier diagnosis of cancer and can inform treatment decisions. Johns Hopkins Kimmel Cancer Center researchers developed a new technology to overcome the inefficiencies and high error rates common among next-generation sequencing techniques that have previously limited their clinical application.

To correct for these sequencing errors, the research team from the Ludwig Center and Lustgarten Laboratory at the Johns Hopkins Kimmel Cancer Center developed SaferSeqS (Safer Sequencing System), a major improvement to widely used technologies based on a previous technology called SafeSeqS (Safe Sequencing System) that Hopkins investigators invented a decade ago. The new SaferSeqS technology detects rare mutations in blood in a highly efficient manner and reduces the error rate of commonly used technologies for evaluating mutations in the blood more than 100-fold.

Their findings were reported May 3 in Nature Biotechnology.

The presence of a mutation in a clinical sample could be an early indicator that a person has developed cancer, says study lead author and M.D./Ph.D. candidate Joshua Cohen. Cancer is a genetic disease, driven by oncogenes and tumor suppressor genes. A small portion of cancer cells shed their DNA into the bloodstream, allowing their mutations to be detected via blood sample. Detecting such mutations in blood rather through surgical biopsy of a cancerous tissue is called “a liquid biopsy.” Such blood-based tests have the potential to detect cancer at an earlier stage, when it can be put into remission by surgery and/or chemotherapy. The challenge, Cohen explains, is that the vast majority of DNA present in the blood sample is shed by noncancer cells, and only a tiny fraction of the DNA is derived from the tumor. In patients with relatively early-stage cancers, a 10 mL blood sample will only contain a handful of molecules with a mutation.

“To detect cancers when they have the best chance of being cured requires a detection method that will pick up cancer signals that are present at extremely low frequencies,” says Cohen. “The technical challenge in detecting these mutations is akin to finding a needle in a haystack.”

The researchers addressed this challenge, with SaferSeqS, by efficiently tagging both strands of each original molecule present in an individual’s blood with a unique barcode. It required new biochemical approaches to do this in an efficient manner with the small number of degraded DNA molecules that are usually present in blood. investigators use the structural redundancy of the double-stranded DNA molecule to distinguish real mutations from errors, an approach called duplex sequencing. If both strands of a DNA molecule contain the identical mutation, it is far more likely that it is a real mutation and not an error.

“What makes SaferSeqS unique is the efficient tagging of both strands of the majority of DNA molecules circulating in the blood, the low error rate achieved through analysis of both strands of these DNA molecules, and the manner in which the molecules of interest are enriched prior to sequencing. Altogether, these advancements underlie the power of the new technology,” says Cohen.

“Every molecule is sacred because it has the potential to be the one with the mutation we’re looking for,” says Cohen. “Because the absolute number of molecules is low, the technology has to be highly efficient at capturing each molecule to sensitively identify mutations.”

To test the specificity and sensitivity of SaferSeqS in a clinically relevant setting, the researchers compared the samples to previous results from the CancerSEEK test, a single blood test that screens for eight common cancer types, developed and reported by the same research team (Science, 2018).

The researchers revisited 74 blood samples from patients with cancer that had false negative results — undetectable mutations — in the 2018 CancerSEEK study using SafeSeqS. In their newest study describing SaferSeqS, the researchers reassessed these blood samples. Using SaferSeqS, they observed a marked improvement in sensitivity, finding previously undetectable mutations in 68% of the samples tested.

“The SaferSeqS strategy affords highly reliable technical specificity, which translates to a better way to provide clinically meaningful results for patients with relatively early-stage and small tumors,” says Cohen.

Taking these results together, the researchers conclude that SaferSeqS is highly sensitive and specific for detecting extremely rare cancer-related mutations, is potentially efficient and cost effective for clinical use, and reduces the error rate of existing mutation-detection approaches more than 100-fold.

The next step, they say, is to validate the results and demonstrate the clinical usefulness of the technology in prospective clinical trials.

The researchers say SaferSeqS will be the underlying platform for future CancerSEEK studies.

Co-authors of the study include from Johns Hopkins Christopher Douville, Jonathan C. Dudley, Brian J. Mog, Maria Popoli, Janine Ptak, Lisa Dobbyn, Natalie Silliman, Joy Shaefer, Cristian Tomasetti, Nickolas Papadopoulos, Kenneth Kinzler and Bert Vogelstein; and Jeanne Tie and Peter Gibbs from the Walter and Eliza Hall Institute of Medical Research and University of Melbourne, Victoria, Australia.

The work was supported by the Lustgarten Foundation for Pancreatic Cancer Research, the Virginia and D.K. Ludwig Fund for Cancer Research, the Marcus Foundation, the Conrad N. Hilton Foundation, and the John Templeton Foundation; Victorian Cancer Agency Clinical Research Fellowship CRF14007 and Translational Research Grant; and National Institutes of Health grants T32 GM007309, U01 CA230691-01, P50 CA228991, U01 CA200469, R37 CA230400-01, CA62924, CA210170 and U01 CA152753.

SaferSeqS and CancerSEEK technologies have been licensed by Exact Sciences. Vogelstein, Kinzler and Papadopoulos are founders of Thrive Earlier Detection and Personal Genome Diagnostics and own equity in Exact Sciences. Kinzler and Papadopoulos are consultants to Thrive Earlier Detection, which was acquired by Exact Sciences in Jan. 2021. Kinzler and Vogelstein are consultants to Sysmex and Eisai. Kinzler, Vogelstein, and Papadopoulos are advisors to CAGE Pharma. Vogelstein is a consultant to Catalio, and Kinzler, Vogelstein, and Papadopoulos are consultants to NeoPhore. Papadopoulos is consultant to Vidium. Douville is a consultant to Thrive Earlier Detection. These and other companies have licensed technologies related to the work described in this paper from Johns Hopkins University. Cohen, Douville, Vogelstein, Kinzler, Tomasetti, and Papadopoulos are inventors on some of these technologies. Licenses to these technologies are or will be associated with equity or royalty payments to the inventors and Johns Hopkins University. Additional patent applications on the work described in this paper are being filed by Johns Hopkins University. The terms of all these arrangements are managed by Johns Hopkins University in accordance with its conflict of interest policies. The remaining authors declare no competing interests.

Featured image: New SaferSeqS technology detects rare mutations in blood in a highly efficient manner and reduces the error rate. Credit: Elizabeth Cooke


Reference: Cohen, J.D., Douville, C., Dudley, J.C. et al. Detection of low-frequency DNA variants by targeted sequencing of the Watson and Crick strands. Nat Biotechnol (2021). https://doi.org/10.1038/s41587-021-00900-z


Provided by Johns Hopkins Medicine

Your Stomach May Be The Secret to Fighting Obesity (Medicine)

Scientists believe a stomach-specific protein plays a major role in the progression of obesity, according to new research in Scientific Reports. The study co-authored by an Indiana University School of Medicine researcher, could help with development of therapeutics that would help individuals struggling with achieving and maintaining weight loss.

Researchers focused on Gastrokine-1 (GKN1) — a protein produced exclusively and abundantly in the stomach. Previous research has suggested GKN1 is resistant to digestion, allowing it to pass into the intestine and interact with microbes in the gut.

In the Scientific Reports study, researchers show that inhibiting GKN1 produced significant differences in weight and levels of body fat in comparison to when the protein was expressed.

“While diet and exercise are critical to maintaining a healthy weight, some individuals struggle with weight loss — even in cases of bariatric surgery, maintaining weight loss can be a challenge,” said David Boone, PhD, associate professor of microbiology and immunology at IU School of Medicine, an adjunct professor in the Department of Biology at the University of Notre Dame and a co-author of the study. “These results are an example of how a better understanding of the gut microbiome and the physiological aspects of obesity — how our bodies regulate metabolism and accumulate body fat — could help inform new therapies.”

Data from the Centers for Disease Control show adult obesity rates have increased to 42.4 percent in the United States. In addition to increasing an individual’s risk of stroke, diabetes, certain cancers and other health issues, obesity can also increase the risk of severe illness due to COVID-19.

Boone and his team conducted a microbiome analysis of mouse models with and without the GKN1 protein expressed. Researchers measured food intake, caloric extraction, blood sugar, insulin and triglyceride levels. They used magnetic resonance imagining to monitor body composition. The team also calculated energy expenditure and observed inflammation levels.

Models without GKN1 weighed less and had lower levels of total body fat and higher percentages of lean mass — despite consuming the same amount of food. When put on a high-fat diet, models without GKN1 showed a resistance to weight gain, increased body fat and hepatic inflammation, which can lead to liver disease. Researchers also found no evidence of adverse effects such as cancer, diabetes, loss of appetite, malabsorption or inflammation — and results were consistent in male and female models.

While more research is needed to determine the efficacy of blocking GKN1 to prevent obesity, researchers said if proved as a viable solution, such therapies could reduce the burden on health care systems and help improve quality of life for patients.

Featured image credit: Photographerlondon/Dreamstime.com


Reference: Overstreet, AM.C., Grayson, B.E., Boger, A. et al. Gastrokine-1, an anti-amyloidogenic protein secreted by the stomach, regulates diet-induced obesity. Sci Rep 11, 9477 (2021). https://doi.org/10.1038/s41598-021-88928-8


Provided by Indiana University School of Medicine

Investigating the Role of Brd4 in Diet-induced Obesity (Biology)

A new study, published in JCI insight, looks at how Brd4, a regulator of the innate immune response, influences diet-induced obesity. The researchers believe that Brd4 could be used as a target for obesity and insulin resistance.

Approximately one-third of the adults and one in five children in the U.S. have obesity problems. Unfortunately, the condition is also associated with the development of other diseases including diabetes, cardiovascular disorders, and cancer. “One of the biggest challenges we face is trying to understand how people develop obesity. If we can understand that, we can develop solutions for treating or preventing these diseases,” said Lin-Feng Chen (MME), a professor of biochemistry.

The researchers investigated the role of the innate immune response, which is the defense system we are born with and the first line of defense against invading microbes. Although the innate immune response is important in fighting against infections, it also causes different kinds of diseases.

Since obesity is accompanied by low levels of inflammation, the researchers wanted to test whether the inflammation is caused by the innate immune response and whether Brd4 is also involved. “Our previous studies showed that Brd4 plays an important role in the innate immune response, so we were trying to understand how it influences the development of diseases such as obesity,” Chen said.

The researchers used mice that lacked the Brd4 gene in their macrophages, which are a part of innate immunity. These cells cause inflammations and have been previously associated with obesity. The mice lacking Brd4 were fed a high-fat diet, which is known to trigger obesity, and they were compared to normal mice the same diet.

“We observed that after several weeks of the high-fat diet, the normal mice became obese while the mice lacking Brd4 did not. They also had reduced inflammation and higher metabolic rates,” Chen said. These results suggest that the mice which did not have Brd4 used fat as the energy source, as opposed to sugar, which is usually used as the primary source of energy.

To understand the molecular mechanism by which Brd4 contributes to obesity, the researchers compared the gene expression profiles during high-fat diet in normal mice and mice that lacked the Brd4 gene. They found that Brd4 was essential for the expression of Gdf3, a protein whose release suppressed the breakdown of fats and lipids in adipose tissues. Without Brd4, the mice had reduced levels the of Gdf3 and increased breakdown of fat.  

The researchers believe that controlling lipid metabolism is only one of the mechanisms through which Brd4 contributes to obesity. Another mechanism they are interested in studying includes the gut microbiome. “We know that bacteria in the gut can sometimes trigger diet-induced obesity. We’re currently working with our MME theme members in the Carl R. Woese Institute for Genomic Biology to figure out how Brd4 modulates microbes to do that,” Chen said. The researchers are also looking into Brd4 inhibitors, that are commonly used to treat cancer, to see whether they can also inhibit the development of obesity.

This work was done in collaboration with Xiangming Hu in Fujian Medical University, a former postdoctoral fellow in Chen’s lab, and Jongsook Kim Kemper, a professor of molecular and integrative physiology.

The study “Brd4 modulates diet-induced obesity via PPARγ-dependent Gdf3 expression in adipose tissue macrophages” can be found at 10.1172/jci.insight.143379.

Featured image: Lin-Feng Chen is interested in studying the role of Brd4 in diseases such as obesity. © Hu et al.


Provided by University of Illinois

Soybean Cyst Nematode is the Most Damaging Soybean Pathogen–and it’s Rapidly Spreading (Agriculture)

The soybean cyst nematode (SCN) is the most damaging pathogen of soybean in the United States and Canada and it is spreading rapidly, according to information compiled by Gregory Tylka and Christopher Marett, nematologists at Iowa State University. SCN was first found in the United States in 1954 and most recent estimates show that SCN results in $1.5 billion in annual yield losses.

“The continuing spread of SCN is alarming, but not surprising,” said Tylka. “Anything that moves soil can move the nematode, including wind, water, and farm machinery.” In an article published in Plant Health Progress, Tylka and Marett report that SCN was found in 55 new counties in the United States and 24 new counties and rural municipalities in Canada between 2017 and 2020. Most dramatically, New York State, which saw SCN in only one county pre-2017, reported SCN in 29 new counties, and Manitoba reported SCN for the first time in 2017.

The nematode is easily overlooked as it often does not cause obvious aboveground symptoms for several years even as it begins to immediately reduce yields. “Farmers often assume that they do not have SCN because the soybeans don’t look sick,” said Tylka. “This is an unfortunate mistake because SCN numbers are low when the nematode is first introduced into a field, but those numbers increase steadily if left unmanaged.

Tylka urges all soybean farmers to test their fields by soil sampling before every second or third soybean crop for the presence of SCN even if the pathogen has never been found in their fields before. He also underscores the need for continued investment in basic and applied research on the biology and management of SCN by private industry, government research funding agencies, and soybean checkoff organizations.

To learn more about the alarming spread of SCN, read “Known Distribution of the Soybean Cyst Nematode, Heterodera glycines, in the United States and Canada in 2020” published in the March issue of Plant Health Progress. His research group also strives to reach soybean farmers and those who advise them through the SCN Coalition. Learn more at http://www.TheSCNCoalition.com.

Featured image: Christopher Marett (left) and Gregory Tylka (right) © Christopher Marett and Gregory Tylka


Provided by American Phytopathological Society

Surfaces Can Be Designed With Antiviral Properties to Mitigate COVID-19 (Medicine)

An optimally designed surface can speed the decay of a viral load

If a respiratory droplet from a person infected with COVID-19 lands on a surface, it becomes a possible source of disease spread. This is known as the fomite route of disease spread, in which the aqueous phase of the respiratory droplet serves as a medium for virus survival.

The lifespan of the respiratory droplet dictates how likely a surface is to spread a virus. While 99.9% of the droplet’s liquid content evaporates within a few minutes, a residual thin film that allows the virus to survive can be left behind.

This begs the question: Is it possible to design surfaces to reduce the survival time of viruses, including the coronavirus that causes COVID-19? In Physics of Fluids, from AIP Publishing, IIT Bombay researchers present their work exploring how the evaporation rate of residual thin films can be accelerated by tuning surfaces’ wettability and creating geometric microtextures on them.

An optimally designed surface will make a viral load decay rapidly, rendering it less likely to contribute to the spread of viruses.

“In terms of physics, the solid-liquid interfacial energy is enhanced by a combination of our proposed surface engineering and augmenting the disjoining pressure within the residual thin film, which will speed drying of the thin film,” said Sanghamitro Chatterjee, lead author and a postdoctoral fellow in the mechanical engineering department.

The researchers were surprised to discover that the combination of a surface’s wettability and its physical texture determine its antiviral properties.

“Continuously tailoring any one of these parameters wouldn’t achieve the best results,” said Amit Agrawal, a co-author. “The most conductive antiviral effect lies within an optimized range of both wettability and texture.”

While previous studies reported antibacterial effects by designing superhydrophobic (repels water) surfaces, their work indicates antiviral surface design can be achieved by surface hydrophilicity (attracts water).

“Our present work demonstrates that designing anti-COVID-19 surfaces is possible,” said Janini Murallidharan, a co-author. “We also propose a design methodology and provide parameters needed to engineer surfaces with the shortest virus survival times.”

The researchers discovered that surfaces with taller and closely packed pillars, with a contact angle of around 60 degrees, show the strongest antiviral effect or shortest drying time.

This work paves the way for fabricating antiviral surfaces that will be useful in designing hospital equipment, medical or pathology equipment, as well as frequently touched surfaces, like door handles, smartphone screens, or surfaces within areas prone to outbreaks.

“In the future, our model can readily be extended to respiratory diseases like influenza A, which spread through fomite transmission,” said Rajneesh Bhardwaj, a co-author. “Since we analyzed antiviral effects by a generic model independent of the specific geometry of texture, it’s possible to fabricate any geometric structures based on different fabrication techniques — focused ion beams or chemical etching — to achieve the same outcome.”

The article “Designing antiviral surfaces to suppress the spread of COVID-19” is authored by Sanghamitro Chatterjee, Janani Srree Murallidharan, Amit Agrawal, and Rajneesh Bhardwaj. It will appear in Physics of Fluids on May 4, 2021 (DOI: 10.1063/5.0049404). After that date, it can be accessed at https://aip.scitation.org/doi/10.1063/5.0049404.

Featured image: Surfaces with taller and closely packed pillars with a contact angle of around 60 degrees show the strongest antiviral effect or shortest drying time. © S. Chatterjee, J.S. Murallidharan, A. Agrawal, and R. Bhardwaj


Provided by American Institute of Physics

Cellphone Converts into Powerful Chemical Detector (Engineering)

With only $50 worth of components, an ordinary cellphone transforms into a sophisticated scientific instrument, capable of identifying chemicals, drugs, and pathogens

Scientists from Texas A&M have developed an extension to an ordinary cellphone that turns it into an instrument capable of detecting chemicals, drugs, biological molecules, and pathogens. The advance is reported in Reviews of Scientific Instruments, by AIP Publishing.

Modern cellphones include high-quality cameras capable of detecting low levels of light and eliminating digital noise through software processing of the captured images. Recent work has taken advantage of this sensitivity to produce cellphone cameras that can be used as portable microscopes and heart rate detectors.

The current advance is based on two types of spectroscopy. One type, known as fluorescence spectroscopy, measures the fluorescent light emitted by a sample. Another, known as Raman spectroscopy, is useful for detecting molecules, such as DNA and RNA, that do not fluoresce or emit light at very low intensities. Both types were used to develop this cellphone detector.

The system includes an inexpensive diode laser as a light source, oriented at right angles to the line connecting the sample and the cellphone camera. The right-angle arrangement prevents back reflected light from entering the camera.

“In addition, this right-angle excitation geometry has the advantage of being easier to use for the analysis of samples where a bulk property is to be measured,” said author Peter Rentzepis.

The investigators studied a variety of samples using their constructed cellphone detector, including common solvents such as ethanol, acetone, isopropyl alcohol, and methanol. They recorded the Raman spectra of solid objects, including a carrot and a pellet of bacteria.

Carrots were chosen for this study because they contain the pigment carotene. The laser light used in their system has a wavelength that is easily absorbed by this orange pigment and by pigments in the bacteria.

The investigators compared the sensitivity of their system to the most sensitive industrial Raman spectrometers available. The ratio of signal to noise for the commercial instrument was about 10 times higher than the cellphone system.

The sensitivity of the cellphone detector could, however, be doubled by using a single RGB channel for analysis. The system has a rather limited dynamic range, but the investigators note that this problem can be easily overcome through several HDR, or High Dynamic Range, applications that combine images from multiple exposures.

The additional components, including the laser, add a cost of only about $50 to the price of a typical cellphone, making this system an inexpensive but accurate tool for detecting chemicals and pathogens in the field.

The article “Cell-phone camera Raman spectrometer” is authored by Dinesh Dhankhar, Anushka Nagpal, and Peter M. Rentzepis. The article will appear in Review of Scientific Instruments on May 4, 2021 (DOI: 10.1063/5.0046281). After that date, it can be accessed at https://aip.scitation.org/doi/10.1063/5.0046281.


Featured image: Photo showing relative size of spectrometer (left) and cellphone (right and at the lower end of the spectrometer). © Peter Rentzepis


Provided by American Institute of Physics