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Crushed Artificial Stones Help Solve the Mystery of 54 Years Old



Princeton researchers have developed a technique to better understand how polymers flow through small channels under pressure. Credit: David Kelly Crow

Princeton researchers have solved a 54-year-old puzzle about why certain fluids are strangely slow under pressure when flowing through porous materials such as soil and sedimentary rocks. The findings could help improve many important processes in the energy, environmental and industrial sectors, from oil recovery to groundwater purification.

The fluid in question is called polymer solution. These solutions (daily examples include cosmetic creams and nasal mucus) include materials made of dissolved polymers or large molecules with many repeating subunits. Normally, when pressure is applied, the viscosity of the polymer solution decreases, flow Faster. However, when passing through materials with many small holes and channels, the solution is more viscous, tends to be ganky, and has a reduced flow rate.

To find the root of the problem, Princeton researchers devised an innovative experiment using clear artificial stone, a see-through porous medium made of small glass beads. This transparent medium allowed researchers to visualize the movement of polymer solutions. Experiments have shown that a long and mysterious increase in the viscosity of a porous medium causes the flow of polymer solution to become disordered, like eddy when boarding an airplane, swirling itself and gumming the work. It became clear that it would occur.

“Surprisingly, it was not possible to predict the viscosity of a polymer solution flowing through a porous medium,” said a study published on November 5, an assistant professor of chemistry and biotechnology at Princeton University. Said Sujit Datta, senior author of.journal Science Advances.. “But this paper finally shows that these predictions are possible, so we have found answers to problems that researchers have not understood for more than half a century.”

“This study has finally made it possible to see exactly what is happening underground or in other opaque porous media when the polymer solution is being pumped,” he said. Christopher Brown, who obtained the issue, said. A student in Datta’s lab and the lead author of the dissertation.

Brown ran the experiment and built the experimental equipment. This is a small rectangular chamber randomly packed with small borosilicate glass beads. The artificial sedimentary rock-like setup was only about half the length of the little finger. On this throat rock, Brown pumped a common polymer solution mixed with fluorescent latex particles and checked the flow of the solution around the beads. Researchers have formulated a polymer solution so that the index of refraction of the material offsets the distortion of light from the beads and makes the entire setup transparent when saturated. Datta’s lab used this technique in an innovative way. See-through soil To study ways to combat agricultural drought Other surveys..

Brown then magnified the pores or holes between the beads under a microscope. These holes are 100 micrometers (one millionth of a meter) in size, or resemble the width of a human hair. Fluid flow Through each pore. As the polymer solution passed through the porous medium, the fluid flow became disordered and the fluid collided with itself, creating turbulence. Surprisingly, fluids usually flow at these velocities, a “laminar flow” rather than a turbulent flow within such narrow pores, and the fluid moves smoothly and steadily. However, as the polymer moved through the pore space, the polymer stretched and generated force, accumulating and creating turbulence in the various pores. This effect became more pronounced when the solution was extruded at higher pressure.

“We were able to identify and record all of these unstable spotted areas, which have a significant impact on the transport of solution through the medium,” says Brown.

Princeton researchers have developed a technique to better understand how polymers flow through small channels under pressure. Credit: David Kelly Crow

Princeton researchers have used data collected from experiments to develop ways to predict the behavior of polymer solutions in real-world situations.

Gareth McKinley, a professor of mechanical engineering at the Massachusetts Institute of Technology who was not involved in the study, provided comments on its importance.

“This study shows that the macroscopically observable increase in pressure drop across the porous medium has a microscopic physical origin in the instability of the viscoelastic flow that occurs on the pore scale of the porous medium. It’s a clear indication, “says McKinley.

Given that viscosity is one of the most basic descriptors of fluid flow, the findings not only help to better understand general polymer solution flow and chaotic flow, but also in the field. It also provides quantitative guidelines for providing information to large-scale applications.

“The new insights we have created can help practitioners in different situations decide how to prescribe the right polymer. Solution “We will use the appropriate pressure needed to carry out the task at hand,” said Datta. “We are particularly excited to apply the findings in groundwater purification.”

Because polymer solutions are inherently sticky, environmental engineers inject the solution into the ground in highly polluted areas such as waste chemical plants and industrial plants. Viscous solutions help push traces of contaminants out of the affected soil. Polymer solutions also help oil recovery by pushing oil out of the pores of underground rocks. In terms of restoration, polymer solutions allow for “pump and treat”. This is a common method for purifying groundwater contaminated with industrial chemicals and metals, including transporting the water to a surface treatment station. “All these uses of polymer solutions, as well as other uses such as separation and manufacturing processes, will benefit from our discoveries,” says Datta.

as a whole, Polymer solution Flow rate Porous medium He put together ideas from multiple disciplines of scientific research and eventually unraveled what began as a long, frustrating and complex problem.

“This study draws a link between polymer physics, turbulence, and earth science studies, following the flow of fluid through underground rocks and aquifers,” said Datta. “It’s a lot of fun sitting on the interface between all these different disciplines.”

Small polymer springs boost environmental cleanup

For more information:
Christopher A. Browne et al, elastic turbulence creates anomalous flow resistance in a porous medium. Science Advances (2021). DOI: 10.1126 / sciadv.abj2619..

Quote: The crushed artificial stone is a 54-year-old mystery (2021) obtained from on November 5, 2021. Helps to decipher (November 5, 2014)

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Antibodies Help Control Harmful Forms of Intestinal Fungi



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Antibodies protection against harmful forms of fungi in the intestine can be disrupted in some patients with Crohn’s disease, a condition caused by chronic inflammation of the intestine, according to a new study by researchers at Weill Cornell Medicine. ..

Previous studies have shown that the immune system plays an important role in maintaining a healthy balance of gut bacteria.The new study was published on November 22nd Nature microbiology, Senior author Iliyan Iliev, associate professor of immunology in medicine, and his team investigated whether it could also play a role in the management of intestinal fungi.

Unlike bacteria, fungi can change shape depending on environmental conditions, and certain forms are harmful to humans. In particular, a type of fungus called Candida albicans changes from a non-pathogenic yeast type to a type that produces hyphae that can invade tissues and cause damage.

Researchers have found that antibodies secreted in the intestine help control the etiology of candida albicans in healthy people, disabling this protective mechanism in people with Crohn’s disease and harmful overgrowth of pathogenic fungi. I have discovered that it can cause. Candida albicans intestinal excess is associated with inflammatory bowel disease and several other conditions that directly or indirectly affect the gastrointestinal tract.

“Anti-intestinal antibodies are involved in maintaining certain intestinal fungi, such as Candida albicans, in a benign, so-called symbiotic form,” said Iriev, a scientist at the Zil Roberts Institute for Inflammatory Intestines. I found that. ” Weil Cornell Medical illness. “This process is interrupted in patients with Crohn’s disease.”

In their experiments, researchers found that an antibody called secretory immunoglobulin A (slgA) in the feces of healthy mice selectively binds to the form of C. albicans in hyphae and stops its spread. discovered. They also found that these antibodies also bind to the hyphae of healthy human feces.

“These antibodies preferentially bind to the hyphae,” said Itai Delon, a PhD student in the lab. Specifically, they bind to sites on the hyphae and produce the virulence factors that these fungi use to harm host tissues. However, the antibody does not preferentially bind to harmless yeast. This suggests that antibodies may help the body maintain a healthy balance of intestinal fungi by preventing the inheritance of harmful forms of fungi.

Researchers also found that patients with Crohn’s disease, who develop severe inflammation of the colon and small intestine, have higher levels of antifungal antibodies in their blood compared to healthy adults. However, these antibodies do not appear to be secreted at high levels in the intestine to counter Candida albicans hyphae. Samples from the colon of these patients reveal an excess of fungi with hyphae.

“Impairment of this regulatory mechanism in mice and patients with Crohn’s disease can contribute to increased hyphal growth in the intestine,” Iriev said.

When researchers added antifungal antibodies to human cells grown in culture with C. albicans, the fungi produced fewer hyphae.

“These antifungal antibodies appear to have some degree of” disarmament “in the hyphae,” Delon said.

The result is that the therapeutic search for antifungal antibodies can be C. It suggests that it may be a way to help patients who develop overgrowth of albicans. Not all patients with this inflammatory bowel disease have overgrowth of this type of fungus, but some may be an important cause of the disease, Iriev said.

“The intestinal fungi in the gut, especially the Candida albicans community, form our immunity,” Iriev said. “We are developing these antibodies and they appear to play a protective role in certain situations.”

The major immune fungus of the intestine against infection

For more information:
Jordan Hindson, Intestinal Mycoviota Modulates Immunity mediated by Antifungal Antibodies, Nature Reviews Gastroenterology & Hepatology (2021). DOI: 10.1038 / s41575-021-00439-z

Provided by
Cornell University

Quote: Antibodies help control harmful forms of enteric fungi obtained on November 30, 2021 from https: // ( November 30, 2021)

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Researchers Are Developing Fast, Accurate Tests to Detect Viruses Like SARS-COV-2



Credit: Unsplash / CC0 public domain

Researchers at the University of Central Florida have developed a device that detects viruses such as SARS-COV-2 in the body more accurately and as quickly as the rapid detection tests commonly used today.

Optical sensors use nanotechnology to accurately identify viruses in seconds. Blood sample..Researchers say the device can tell if someone has it with 95% accuracy virusSignificant improvements to the current rapid testing, which experts warn, may be less accurate. Testing for the virus is important for early treatment and prevention of the spread of the virus.

The results are detailed in a new study in the journal Nano letter..

Researchers tested the device with a sample of dengue virus, a mosquito-borne pathogen that causes dengue fever and poses a threat to people in the tropics. However, this technology can be easily adapted to detect other viruses such as SARS-COV-2, says Debashis Chanda, a professor at UCF’s NanoScience Technology Center, co-author of the study. ..

“High-sensitivity optical sensors, along with the rapid manufacturing approach used in this task, can transform this promising technology with a high degree of specificity and accuracy for detection of any virus, including SARS-COV-2 and its mutations. I promise, “says Chanda. “Here we have demonstrated a reliable technique that combines a genetic code such as PCR with an optical system on a chip to accurately detect the virus directly from the blood.”

This device closely matches the accuracy of gold standard PCR-based tests, but with near-instantaneous results rather than days of reception. Its accuracy is significantly improved over the current rapid antigen test warned by the U.S. Food and Drug Administration and the Centers for Disease Control and Prevention, and is inaccurate if the viral load is low or if the test instructions are not followed correctly. Results may occur.

The device works with a gold nanoscale pattern that reflects the virus’s signature that is set to detect on blood samples. Different viruses can be detected by using different DNA sequences that selectively target a particular virus.

The key to device performance is the ability to detect viruses directly from blood samples without the need for sample preparation or purification. This speeds up testing and improves accuracy.

“Most of the biosensor demonstrations in the literature use buffers as a test matrix to contain targeted analytes,” says Chanda. “But these approaches are not practical in real-world applications. Complex body fluids containing target biomarkers, such as blood, are the main cause of sensing, while at the same time the main cause of protein contamination leading to sensor failure. Because it is the cause. “

Researchers have confirmed the effectiveness of the device in multiple tests using different viral concentration levels and solution environments, including the presence of non-target viral biomarkers.

Abraham Vazquez Guardard, a postdoc at Northwestern University who was the lead author of the study and worked as a postdoctoral student in Chanda’s lab, said he was excited about the possibility.

“There was a previous demonstration of optical biosensing with human serum, but it requires offline complex and dedicated sample preparation by skilled personnel. This is a product not available in regular point of care applications.” Vazquez-Guardado says. “This study demonstrates for the first time an integrated device that separates plasma from blood and detects target viruses without pretreatment, with potential for practical use in the near future.”

According to Chanda, the next step in the study will include adapting the device to detect more viruses.

Portable, Affordable, Accurate, Fast: Team Invents New COVID-19 Test

For more information:
Abraham Vazquez-Guardado et al., DNA-modified plasmon sensor for detecting viral biomarkers directly from blood, Nano letter (2021). DOI: 10.1021 / acs.nanolett.1c01609

Quote: The researchers obtained SARS-COV-2 (2021, November 29, 2021) from https: // on November 29, 2021. ) Develop fast and accurate tests to detect viruses like. sars-cov-.html

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Drivers to Face Traffic Delays This Week on I-25 Near Colorado Springs



A paving project on Interstate 25 south of Colorado Springs will delay traffic during the next several days, according to a Colorado Department of Transportation news release.

The paving project, which includes filling potholes with asphalt and making road repairs between Santa Fe Boulevard and South Academy Boulevard near Fort Carson, will reduce traffic to a single lane during daytime hours (9 a.m.-3 p.m.), with a speed limit of 55 mph, Tuesday through Thursday, the agency said.

Drivers are encouraged to use alternate routes during the maintenance period and those who drive through the construction zone are advised to slow down, allow extra space between vehicles and build in extra travel time. Fines will be doubled in the work zones, the release said.

1 killed in Pueblo County crash

The maintenance is a facet of a larger project designed to improve safety around military facilities in the Pikes Peak Region, the release said.

For more traffic information visit

Colorado Springs weather: Record-breaking temps possible Monday, throughout week

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