Tech

Mass incarceration is as much an environmental problem as it is a social one, according to a new Portland State University study that finds increases in incarceration are significantly associated with increases in industrial emissions.

Julius McGee, the study's lead author and an environmental sociologist, argues that the construction and maintenance of prisons, the production of goods and materials used inside prisons and the use of prison labor to manufacture industrial equipment for the government and private companies all contribute to increased emissions.

"As we shift the population into prisons, we see a clear impact on how economic development contributes to emissions," said McGee, an assistant professor of urban studies and Black Studies at PSU.

The prison population began to grow in the 1970s, largely as a punitive response to the social movements that emerged post-World War II, McGee said. Today, more than 2.3 million people are incarcerated in the U.S.

Between 1980 and 2004, 936 prisons were built in the U.S., compared with the 711 prisons built in the 168 years prior. McGee says the construction of new prisons, as well as the renovation of existing prisons, require substantial amounts of fossil fuels. Cement, for example, is one of the largest emitters of carbon dioxide in the built environment.

"This is housing infrastructure that otherwise wouldn't have been built," McGee said, adding that most incarcerated people are forcibly removed from inner-city neighborhoods and transported to massive warehouse-like structures in rural areas.

Mass incarceration disproportionately affects black and brown people -- those whose contributions to carbon dioxide emissions are relatively small, McGee said. But once they go to prison, they become coerced consumers of industrial goods and increased industrial activity. Prisoners require beds, clothing, hygiene products and furniture -- and the prison supply companies that manufacture and distribute these goods have continuously expanded their production in response to a growing incarcerated population.

Lastly, prison labor programs help to stimulate industrial growth by reducing the cost of labor. Prisoners are paid as little as $.023 to $1.15 per hour or sometimes not at all.

"Employment in industrial manufacturing has gone down, but manufacturing in total dollars has not gone down," McGee said. "What's changed is where the labor and jobs are."

If companies did not use prison labor, McGee says, they'd use unionized labor, which requires them to invest more in workers and less into expanding growth.

"Industrial manufacturing has exploited workers, consumers, and the environment by continually reducing the cost of labor, increasing the demand of industrial goods, and increasing the use of fossil fuels," the study reads. "Incarceration allows these patterns to continue unabated, and in many instances provides the tools necessary to accelerate the pace at which such patterns recur."

Recently, there have been a number of electric vehicle (EV) battery fire incidents. Unlike the batteries used in small mobile devices, such as smartphones, the battery pack of an EV is composed of hundreds of battery cells, and any instability can cause major casualties and property damage. Amid various efforts to pinpoint the cause of battery fires, Korean researchers have developed a new analysis method to evaluate the thermal stability of EV batteries.

The Korea Institute of Science and Technology (KIST) announced that a research team led by Dr. Wonyoung Chang of the KIST Center for Energy Storage Research and Dr. Seung Min Kim of the Carbon Composite Materials Research Center of the Jeonbuk Branch built a real-time analysis platform for evaluating the thermal stability of the cathode material of a battery using a transmission electron microscope, through which they identify the thermal degradation mechanism according to the changes in the chemical composition of the 1)high-nickel cathode material for EVs.

The cathode material of an EV battery is one of the key factors that determine the battery capacity and thus the driving range. The cathode is manufactured by mixing various metals such as nickel, cobalt and aluminum or nickel, manganese, and cobalt according to the designated mixing ratio, and researchers from companies and academic circles are endeavoring to find an appropriate composition ratio to increase the driving range of EVs.

The cathode material contains nickel, and there is a positive correlation between the nickel content and the capacity. Also, since nickel is relatively cheaper than cobalt, adding more nickel effectually lowers the unit cost of an EV battery. However, a fatal weakness of nickel is that it reduces the stability of the battery as it reacts easily to the external environment. In the case of the cathode material used for the 2)third-generation EVs, which are currently in development, the nickel content has been increased to 80% or higher, and the consequent deterioration in stability must be improved to ensure safety.

Battery fires are primarily initiated by a violent exothermic reaction between the charged oxide-based cathode material and the flammable liquid electrolytes. Thus, the research team at KIST focused on the surface of the cathode in contact with the electrolytes and applied a variety of transmission electron microscopy methods (electron energy loss spectroscopy, electron diffraction, etc.) for close observation and analysis of the crystal structure of the cathode and the chemical changes in the constituents resulting from a temperature increase. As a result, it was possible to identify the cause of reduced thermal stability of the battery based on the chemical composition of the NCA (nickel, cobalt, aluminum) cathode material and the role of the constituent elements to ensure the safety of the battery.

The KIST research team investigated that an increase in nickel compared to the aluminum content in the NCA cathode material improves the battery capacity, but it significantly reduces thermal stability in the upper charging limit (67% reaction of total lithium ions). An analysis showed that there was a lack of aluminum not participating in the redox reaction, and this leads to the formation of a new phase (O1 phase) that can reduce thermal stability during the charging process. The surface of the new unstable phase was found to be the ultimate cause of reduced thermal stability.

Dr. Wonyoung Chang from KIST said, "There have been a series of EV fires worldwide, and the source of the fire, in many cases, was the battery. This study confirmed the importance of a chemical composition design that ensures thermal stability in developing high-performance cathode materials."

Dr. Seung Min Kim from the Jeonbuk Branch of KIST said, "Ensuring thermal stability of the cathode material where exothermic reactions begin is key to popularizing EVs. The advanced analysis techniques developed in this study will help determine the effects of elements in trace amounts and in turn lead to the development of high-performance cathode materials that are guaranteed to be safe."

Philadelphia, December 4, 2020 - Researchers from a consortium of hospitals including Children's Hospital of Philadelphia (CHOP) have identified factors that make children with diabetic ketoacidosis more likely to experience acute kidney injury. Analyzing data from a large, multicenter clinical trial, the researchers also found that children who experience acute kidney injury are more likely to also experience subtle cognitive impairment and demonstrate lower IQ scores, suggesting a pattern of multiple organ injury. The findings were published online today in JAMA Network Open.

Multiple recent studies have shown that organ injuries in children with diabetic ketoacidosis occur more frequently than previously thought. One recent retrospective study found that acute kidney injury commonly occurs in these children. Earlier analysis of a large, multicenter study demonstrated cerebral injury commonly occurs in diabetic ketoacidosis. Together, these studies raised the possibility of an underlying pathophysiology that connects these injuries across the body if the presence of these injuries were linked in patients.

"We wanted to look at these issues in a more prospective manner," said Sage Myers, MD, an attending physician in the Emergency Department at CHOP and first author of the study. "With 13 participating emergency departments in the Pediatric Emergency Care Applied Research Network, we had the ability to not only study the frequency of acute kidney injury in these children, but also the underlying factors associated with injury and whether there is an association between the occurrence of acute kidney injury and cerebral injury, which would suggest a possible linkage between the mechanisms of injury underlying both."

The researchers studied 1,359 episodes of diabetic ketoacidosis in children. Acute kidney injury occurred in 584 (43%) of those episodes, and 252 of those episodes (43%) were classified as either stage 2 or 3, representing more severe cases of kidney injury. When assessing whether acute kidney injury was associated with cognitive issues, children with kidney injuries had lower scores on short-term memory tests during diabetic ketoacidosis, as well as lower IQ scores three to six months after recovering from the condition. These differences persisted after adjusting for the severity of diabetic ketoacidosis and demographic factors like socioeconomic status.

"If we can identify the mechanisms of kidney injury after diabetic ketoacidosis, it can help in the development of new therapeutic and preventive strategies," said Nathan Kuppermann, MD, professor and chair of emergency medicine at UC Davis Health, and senior author and co-principal investigator of the study. "We're also hoping to focus future research on how diabetic ketoacidosis causes simultaneous, multi-organ injuries such as what we demonstrated in this study."

A new system for measuring solar performance over the long term in scalable photovoltaic systems, developed by Arizona State University researchers, represents a breakthrough in the cost and longevity of interconnected power delivery.

When solar cells are developed, they are "current-voltage" tested in the lab before they are deployed in panels and systems outdoors. Once installed outdoors, they aren't usually tested again unless the system undergoes major issues. The new test system, Suns-Voc, measures the system's voltage as a function of light intensity in the outdoor setting, enabling real-time measurements of performance and detailed diagnostics.

"Inside the lab, however, everything is controlled," explained Alexander Killam, an ASU electrical engineering doctoral student and graduate research associate. "Our research has developed a way to use Suns-Voc to measure solar panels' degradation once they are outdoors in the real world and affected by weather, temperature and humidity," he said.

Current photovoltaic modules are rated to last 25 years at 80 percent efficiency. The goal is to expand that time frame to 50 years or longer.

"This system of monitoring will give photovoltaic manufacturers and big utility installations the kind of data necessary to adjust designs to increase efficiency and lifespans," said Killam, the lead author of "Monitoring of Photovoltaic System Performance Using Outdoor Suns-Voc," for Joule.

For example, most techniques used to measure outdoor solar efficiency require you to disconnect from the power delivery mechanism. The new approach can automatically measure daily during sunrise and sunset without interfering with power delivery.

"When we were developing photovoltaics 20 years ago, panels were expensive," said Stuart Bowden, an associate research professor who heads the silicon section of ASU's Solar Power Laboratory. "Now they are cheap enough that we don't have to worry about the cost of the panels. We are more interested in how they maintain their performance in different environments.

"A banker in Miami underwriting a photovoltaic system wants to know in dollars and cents how the system will perform in Miami and not in Phoenix, Arizona."

"The weather effects on photovoltaic systems in Arizona will be vastly different than those in Wisconsin or Louisiana," said Joseph Karas, co-author and materials science doctoral graduate now at the National Renewable Energy Lab. "The ability to collect data from a variety of climates and locations will support the development of universally effective solar cells and systems."

The research team was able to test its approach at ASU's Research Park facility, where the Solar Lab is primarily solar powered. For its next step, the lab is negotiating with a power plant in California that is looking to add a megawatt of silicon photovoltaics to its power profile.

The system, which can monitor reliability and lifespan remotely for larger, interconnected systems, will be a major breakthrough for the power industry.

"Most residential solar rooftop systems aren't owned by the homeowner, they are owned by a utility company or broker with a vested interest in monitoring photovoltaic efficiency," said Andre' Augusto, head of Silicon Heterojunction Research at ASU's Solar Power Laboratory and a co-author of the paper.

"Likewise, as developers of malls or even planned residential communities begin to incorporate solar power into their construction projects, the interest in monitoring at scale will increase, " Augusto said.

According to Bowden, it's all about the data, especially when it can be monitored automatically and remotely -- data for the bankers, data for developers, and data for the utility providers.

If Bill Gates' smart city, planned about 30 miles from Phoenix in Buckeye, Ariz., uses the team's measurement technology, "It could become the IoT of Photovoltaics," said Bowden.

A new study by the UC Davis MIND Institute finds a connection between gestational age and attention deficit/hyperactivity disorder (ADHD) symptoms in children with Down syndrome. The research, published in Scientific Reports, focused on children born at 35 weeks gestation or older. It found that earlier gestational age was linked to increased ADHD symptoms later in childhood. Gestational age is the length of time a fetus has developed since the beginning, or gestation, of a pregnancy.

"Despite growing evidence that gestational age predicts later symptoms of ADHD in the general population, this hasn't been studied in children with Down syndrome," said Laura del Hoyo Soriano, neuropsychologist and postdoctoral scholar in the Department of Psychiatry and Behavioral Sciences and lead author on the study. "That makes this study meaningful and an important first step to understanding factors related to ADHD symptoms in this population."

The study included 49 boys and 56 girls (6-18 years old) born at least 35 weeks gestation with Down syndrome. The children were part of the Down Syndrome Cognition Project.

The researchers based their study on the children's medical records and questionnaires filled out by their mothers, incorporating well-established measures for ADHD symptoms and intelligence. They found that an earlier gestational age was associated with more symptoms of ADHD, even after adjusting for the child's age and cognitive abilities.

Distinguishing ADHD symptoms from intellectual disability linked to Down syndrome

ADHD commonly occurs with Down syndrome. It is generally characterized by inattention, distractibility, poor impulse control and trouble focusing, and it can be difficult to distinguish between symptoms that are due to ADHD and those due to the intellectual disability associated with Down syndrome.

"It's complicated to determine what is a comorbid diagnosis and what is part of the Down syndrome phenotype. That's why it is important to study factors associated with ADHD symptoms in people with intellectual disability," noted del Hoyo Soriano.

She points out that in the study, there was no link between general cognition and ADHD symptoms, reinforcing the separate diagnosis of ADHD.

"It is interesting that gestational age is also related to ADHD symptoms in the general population," said Leonard Abbeduto, a co-author of the study and director of the UC Davis MIND Institute. "So, our findings are consistent with the idea that ADHD is not inherent in Down syndrome, but more likely the result of additional factors."

In their analysis, the researchers considered many factors such as the participants' age, sex, cognitive level, family income, and their mother's education and age at birth. They also completed several analyses to ensure the validity of their results. This included removing children who were taking medication for their ADHD.

ADHD and age

The study suggests that ADHD may present in different ways as individuals age. Younger children with Down syndrome generally showed more ADHD symptoms compared to older ones. This is in line with research done in the general population.

"More attention needs to be paid to the care and follow-up of infants born pre-term, even those between 35 and 39 weeks, and perhaps even more so for those with Down syndrome," said del Hoyo Soriano. "The implications for early interventions could be significant."

Heart disease is the main cause of death in developed countries. There is evidence that shows that factors related to lifestyle, such as diet, have an influence on developing these kinds of diseases. But, do they have any effect on patients who are already ill?

A team from the University of Córdoba, Queen Sofia University Hospital and the Maimonides Biomedical Research Institute of Cordoba (IMIBIC) has published a study in PLOS Medicine. This study compares the effects of two different healthy diets on the endotheliem, the walls that cover the arteries. 1002 patients who had previously had an acute myocardial infarction took part in the study and were monitored over the course of a year.

The research group had previously worked on a similar study with healthy patients, however, this is the first time it has been done with ill patients, who are more likely to have other heart attacks. "The degree of endothelial damage predicts the occurrence of future cardiovascular events, as in acute myocardial infarctions. If we can take action at the inital stages, prompting endothelium regeneration and better endothelial function, we can help to prevent heart attacks and heart disease from reoccurring", explains José López Miranda, researcher on the study and coordinator of the "Nutritional Genomics and Metabolic Syndrome" research group at the Maimonides Biomedical Research Institute of Cordoba, made up of researchers belonging to the Internal Medicine Clinical Management Unit at Queen Sofia University Hospital, to the University of Córdoba (UCO) and to CIBERobn, the Online Biomedical Research Centre for Obesity and Nutrition.

During the study, half of the patients were told to follow a Mediterranean diet, based on using plenty of virgin olive oil, eating fruit and vegetables every day, and having three servings of legumes, three of fish and three of nuts a week. In addition, they were told to cut down on eating meat, especially red meat, and to avoid additional fats such as margarine and butter as well as food that is high in sugar.

In contrast, the other group was told to follow a low-fat diet, based on limiting all kinds of fat, both animal and plant, and increasing their intake of complex carbohydrates. They were told to cut down on red meat, to choose low-fat dairy products, to avoid eating nuts and to reduce their intake of sweets and pastries.

In the first place, the vasodilation capacity that the patients' arteries had was analyzed, which is very important in order to adapt to different circumstances, like exercise or stressful situations. Secondly, the degree of permanent endothelium damage was assessed. Lastly, the reparation ability of the arteries by means of endothelial progenitor cells, or stem cells, was measured.

"We observed that the Mediterranean diet model induced better endothelial function, meaning that the arteries were more flexible in adapting to different situations in which greater blood flow is required. Besides, the endothelium's ability to regenerate was better and we detected a drastic reduction in damage to the endothelium, even in patients at severe risk", explains José López Miranda.

Though the Mediterranean diet, rich in monounsaturated fatty acids, had already been proven to be a good strategy in order to improve endothelial function in overweight patients as well as patients with high cholesterol, this is the first time that the benefits of following a Mediterranean diet have been shown among patients with heart disease, helping them to reduce the likelihood of having another heart attack.

The group of so-called metal halide perovskites as materials has revolutionized the field of photovoltaics in recent years. Generally speaking, metal halide perovskites are crystalline materials that follow the structure ABX3, with varying composition. Here, A, B, and X can represent a combination of different organic and inorganic ions. These materials have a number of properties that are ideal for use in solar cells and could help to make optoelectronic devices such as lasers, light-emitting diodes (LEDs), or photodetectors much more efficient. With regard to the development of a resource- and energy-efficient technology, the relevance of research on these materials is very high.

The advantageous properties of metal halide perovskites include their high light-harvesting capacity and their remarkable ability to efficiently convert solar energy into electrical energy. Another special feature of these materials is that both charge carriers and ions are mobile within them. While charge carrier transport is a fundamental process required for the photovoltaic operation of the solar cell, ionic defects and ion transport often have undesirable consequences on the performance of these devices. Despite significant progress in this field of research, many questions regarding the physics of ions in perovskite materials remain open.

On the way to a better understanding of these structures, the Technical Universities of Chemnitz and Dresden have now taken a big step forward. In a joint investigation by the research groups around Prof. Dr. Yana Vaynzof (Chair of Emerging Electronic Technologies at the Institute of Applied Physics and Center for Advancing Electronics Dresden - cfaed, TU Dresden) and Prof. Dr. Carsten Deibel (Optics and Photonics of Condensed Matter, Chemnitz University of Technology) under the leadership of Chemnitz University of Technology, the two teams uncovered the ionic defect landscape in metal halide perovskites. They were able to identify essential properties of the ions that make up these materials. The migration of the ions leads to the presence of defects in the material, which have a negative effect on the efficiency and stability of perovskite solar cells. The working groups found that the motion of all observed ions, despite their different properties (such as positive or negative charge), follows a common transport mechanism and also allows the assignment of defects and ions. This is known as the Meyer-Neldel rule. The results were published in the renowned journal
"Nature Communications" (11, 6098 (2020)) .

"Probing the ionic defect landscape of perovskite materials is not a simple task," says Sebastian Reichert, research assistant at the Chair of Optics and Photonics of Condensed Matter at Chemnitz University of Technology and lead author of the publication. "We needed to perform extensive spectroscopic characterization on perovskite samples in which the defects were intentionally introduced and their type and density were gradually tuned. Therefore, the expertise of both teams was invaluable," Reichert explains.
Clarifying basic transport mechanisms

"One of the most important results of our study is the intricate interplay between the ionic and electronic landscapes in perovskite materials," adds Prof. Vaynzof, "By changing the density of the various ionic defects in perovskite materials, we observe that the built-in potential and the open-circuit voltage of the devices are affected." This highlights that defect engineering is a powerful tool to enhance the performance of perovskite solar cells beyond the state of the art.

The joint study also found that all ionic defects meet the so-called Meyer-Neldel rule. "This is very exciting since it reveals fundamental information about the hopping processes of ions in perovskites," says Prof. Deibel. "We currently have two hypotheses regarding the origin of this observation and we plan to investigate those in our future studies."

Scientists have recently revealed, both theoretically and experimentally, that germanium atoms can arrange themselves into a 2D "bitriangular" lattice on zirconium diboride thin films grown on germanium single crystals to form a "flat band material" with an embedded "kagome" lattice. The result provides experimental support to a theoretical prediction of flat bands emerging from trivial atomic geometry and indicates the possibility of their existence in many more materials.

The human mind is naturally drawn to objects that possess symmetry; in fact, the notion of beauty is often conflated with symmetry. In nature, nothing epitomizes symmetry more than crystals. Since their discovery, crystals have attracted a great deal of attention not only by their unique "symmetrical" aesthetic appeal but also by their unique properties. One of these properties is the behavior of electrons inside a crystal. From a physical point of view, an electron within a crystal can be fully characterized by its energy and a quantity called "crystal momentum," which relates to how fast the electron moves in a crystal. The relationship between the energy and crystal momentum of electrons is what scientists refer to as "band structure," which, put simply, is the allowed energy levels for the electrons within the crystal.

Recently, materials scientists have turned their attention towards what are called "flat band materials"--a class of materials possessing a band structure in which the energy does not vary with the crystal momentum and hence resembles a flat line when plotted as a function of crystal momentum--owing to their ability to give rise to exotic states of matter, such as ferromagnetism (iron-like spontaneous magnetism) and superconductivity (zero resistance to electricity flow). Generally, these "flat bands" are observed in special 2D structures that go by names like "checkerboard lattice," "dice lattice," "kagome lattice," etc. and are typically observed either within the crystal or at the surface of layered materials. A pertinent question thus presents itself--is it possible to embed such lattices into completely new 2D structures? Efforts to design 2D materials have focused on answering this question, and a recent finding suggests that the answer is a "yes."

Now, in a study published in Physical Review B as a Rapid Communication, an international team of scientists from the Japan Advanced Institute of Science and Technology (JAIST), the University of Tokyo, the Japan Atomic Energy Agency, and Institute for Molecular Science in Japan and Tamkang University in Taiwan, led by Dr. Antoine Fleurence and Prof. Yukiko Yamada-Takamura, has reported a possible new flat band material obtained from germanium (Ge) atoms arranging themselves into a 2D "bitriangular" lattice on zirconium diboride thin films grown on germanium single crystals. The published study is also trending as a #PRBTopDownload on the official Physical Review B handle on Twitter: https://twitter.com/PhysRevB/status/1327606715630620674. While the team had already grown this 2D material years ago, they were only recently able to unveil its structure.

Last year, a part of the team published a theoretical paper in the same journal underlining the conditions under which a 2D "bitriangular" lattice can form a flat band. They found that this is related to a "kagome" (meaning weaved basket pattern in Japanese) lattice--a term originally coined by Japanese physicists in the '50s to study magnetism. "I was really excited when I found out that the electronic structure of kagome lattice can be embedded into a very different-looking 2D structure", recalls Prof. Chi-Cheng Lee, a physicist at Tamkang University, Taiwan, involved in the study, who predicted the presence of flat bands in the "bitriangular" lattice.

The prediction was finally confirmed after the team, in their current study, characterized the prepared 2D material using various techniques such as scanning tunneling microscopy, positron diffraction, and core-level and angle-resolved photoelectron emission; and backed up the experimental data with theoretical calculations to reveal the underlying "bitriangular" lattice.

"The result is really exciting as it shows that flat bands can emerge even from trivial structures and can possibly be realized in many more materials. Our next step is to see what happens at low temperature, and how it is related to the flat bands of the Ge bitriangular lattice," says Dr. Fleurence, who is also the first author of this paper.

Indeed, who would've thought that a typical, run-of-the-mill semiconductor like germanium could offer such exotic and unprecedented possibilities? The 2D world might have more surprises up its sleeve than we imagine.

Indolizines are a group of substances with biological and optical properties. A team of chemists from RUDN University developed a new approach to the synthesis of indolizines using pyridinium salts and enamiones. The new substances turned out to be able to emit light in the green range which can be useful for medical applications. The results of the study were published in the Molecules journal.

Indolizines are organic substances that contain two carbon cycles and one atom of nitrogen. They are used to produce dyes and solar panels, as well as anti-tumor and anti-diabetes drugs. Indolizines do not occur naturally but are constructed in labs, usually using the reactions of cycloaddition. These reactions involve pyridinium salts--electrically neutral molecules with positively and negatively charged 'poles' that balance each other. A team of chemists from RUDN University discovered an unexpected reaction in which, instead of cycloaddition, a pyridinium salt undergoes two other consecutive processes. The end products of this reaction are indolizines with fluorescent properties.

"We found out that pyridinium salts that contain a methyl group bound with ?(2) tend to enter into an unexpected domino reaction with enaminones, and consecutive cycloisomerization and cyclocondensation take place, while the reactions of cycloaddition that are typical for pyridinium salts are not observed," said Alexey Festa, PhD, a Senior Lecturer at the Department of Organic Chemistry, RUDN University.

A team of chemists from RUDN University, MSU, and KU Leuven (Belgium) suggested an approach based on their earlier studies of reactivity of pyridinium salts. The team studied 1-(cyanomethyl)-2-alkylpyridinium salts in reactions with enaminones and chose optimal conditions for the production of indolizines. By changing the ratio of the initial components, the team managed to gain only a 50% reaction yield. However, after other pyridinium salts were used, the yield increased to 82%. The two-stage reaction turned out to be of the domino type, i.e. the first stage initiated the second one in the same flask without any additions of new reagents or changes in reaction conditions. The team used X-ray structural analysis to study the new indolizines and also paid attention to their optical properties.

Eight of the new indolizines were capable of intensive fluorescence (i.e. of absorbing light with a certain wavelength and emitting light with a longer one). This mechanism is based on the excitement of electrons, that is, their movement to a higher energy level under the influence of photons. This process is accompanied by energy release, and a part of it is emitted in the form of photons with reduced energy and therefore increased wavelength. The indolizines synthesized by the team were particularly effective in absorbing emissions with the wavelength of 403-420 nm that belong to the blue-violet range bordering on the UV light. The wavelength of the light emitted by the indolizines amounted to 505-528 nm which corresponds to the green range of the spectrum. These properties make indolizines a promising material for the manufacture of fluorescent tags that are used to study biological objects.

"Pyrido[2,3-b]indolizines obtained in the course of our reaction showed certain fluorescent properties. Namely, they emitted green light with a high quantum yield (a parameter that characterizes the efficiency of this process). The lowest yield values amounted to 55-63% and in the case of one new indolizine the yield reached 82%," added Alexey Festa from RUDN University.

OAK BROOK, Ill. (December 4, 2020) - Breast cancer screening with digital breast tomosynthesis (DBT) offers significant advantages over digital mammography, including improved cancer detection and lower false negative rates, according to a study published in Radiology.

In DBT, an X-ray camera moves in an arc over the breast, acquiring images from different angles. The pictures are processed into a 3D-like image that can be scrolled through a millimeter at a time. This eliminates the problem of overlapping tissue that often hides cancers and results in recalls for additional imaging in digital mammography.

"With DBT, you can really feel like you're combing through the breast tissue instead of just looking at flat pictures," said study lead author Melissa A. Durand, M.D., associate professor of diagnostic radiology and biomedical imaging at Yale University School of Medicine and Smilow Cancer Hospital in New Haven, Connecticut.

While research has illuminated DBT's edge over digital mammography in cancer detection, its impact on patient survival has not been established.

For the new study, Dr. Durand and colleagues looked at more than 380,000 screening examinations to compare the performance of DBT and digital mammography. Among the performance metrics they assessed were the rates of false negative screening examinations, or cancers detected within a year of a normal mammogram. Since false negative cancers tend to be more aggressive than screen-detected cancers, a reduction in them may be considered a surrogate for longer-term screening outcomes such as advanced disease or death.

"Using false negative cancer rates is a way to get an idea of how a tool can affect morbidity/mortality in a more reasonable time frame than a randomized clinical trial," Dr. Durand said.

Analysis showed that screening with DBT improved sensitivity and specificity for breast cancer and identified more invasive cancers with fewer nodal or distant metastases.

"Our results build on past studies that have shown that DBT improves performance outcomes for breast cancer screening," Dr. Durand said. "With DBT, we show we are detecting more invasive cancers, but they are cancers with favorable prognostic criteria, which means these patients would have more treatment options."

Screening with DBT demonstrated a trend toward lower rates for overall false negatives and symptomatic false negatives, or those that present with a symptom like pain, discharge or a lump.

The results also showed advantages for DBT in imaging women with mammographically dense breasts, or breasts with a higher proportion of fibrous and glandular tissue compared with fatty tissue. Cancers can be more difficult to see in dense breasts, and breast density itself is a risk factor for cancer.

Recall rates were significantly lower in both heterogeneously dense breasts--those with mostly dense tissue but with some areas of non-dense tissue--and extremely dense breasts in the DBT group compared to digital mammography.

"We also saw significantly higher cancer detection rates with DBT in women with heterogeneously dense breasts compared to digital mammography," Dr. Durand said. "With women who have extremely dense breasts, the cancer detection was higher, but not significantly so, which makes sense. You need a bit of fat to provide contrast to the fibroglandular tissue in order to detect abnormalities, whether you are using DBT or digital mammography. This highlights a group of women who would benefit from supplementary screening."

The study results add to a growing body of literature supporting DBT for regular breast cancer screening. Its superior cancer detection translates to fewer recalls and fewer additional imaging exams needed.

While DBT studies carry a higher radiation dose than that of 2D mammography, a technique known as synthesized DBT essentially halves the radiation dose.

"Together with reduced recall rates and, thus, less patient anxiety, I would anticipate that DBT will continue to move forward as the standard of care to replace regular mammography," Dr. Durand said.

Astronomers have caught a rare look at a rapidly fading shroud of gas around an aging star. Archival data from NASA's Hubble Space Telescope reveal that the nebula Hen 3-1357, nicknamed the Stingray nebula, has faded precipitously over just the past two decades. Witnessing such a swift rate of change in a planetary nebula is exceeding rare, say researchers.

Images captured by Hubble in 2016, when compared to Hubble images taken in 1996, show a nebula that has drastically dimmed in brightness and changed shape. Bright, blue, fluorescent tendrils and filaments of gas toward the center of the nebula have all but disappeared, and the wavy edges that earned this nebula its aquatic-themed name are virtually gone. The young nebula no longer pops against the black velvet background of the vast universe.

"This is very, very dramatic, and very weird," said team member Martín A. Guerrero of the Instituto de Astrofísica de Andalucía in Granada, Spain. "What we're witnessing is a nebula's evolution in real time. In a span of years, we see variations in the nebula. We have not seen that before with the clarity we get with this view."

Researchers discovered unprecedented changes in the light emitted by glowing nitrogen, hydrogen, and oxygen being blasted off by the dying star at the center of the nebula. The oxygen emission, in particular, dropped in brightness by a factor of nearly 1,000 between 1996 and 2016.

"Changes in nebulae have been seen before, but what we have here are changes in the fundamental structure of the nebula," said Bruce Balick of the University of Washington, Seattle, leader of the new research. "In most studies, the nebula usually gets bigger. Here, it's fundamentally changing its shape and getting fainter, and doing so on an unprecedented time scale. Moreover, to our surprise, it's not growing any larger. Indeed, the once-bright inner elliptical ring seems to be shrinking as it fades."

Ground-based observations of other planetary nebulae have shown hints of changes in brightness over time, but those speculations haven't been confirmed until now. Only Hubble can resolve the changes in structure in this tiny nebula. The new paper examines every image of the Stingray nebula from Hubble's archives.

"Because of Hubble's optical stability, we are very, very confident that this nebula is changing in brightness with time," added Guerrero. "This is something that can only be confirmed with Hubble's visual acuity."

The researchers note the nebula's rapid changes are a response to its central star, SAO 244567, expanding due to a temperature drop, and in turn emitting less ionizing radiation.

A 2016 study by Nicole Reindl, now of the University of Potsdam, Germany, and a team of international researchers, also using Hubble data, noted the star at the center of the Stingray nebula, SAO 244567, is special in its own right.

Observations from 1971 to 2002 showed the temperature of the star skyrocketing from less than 40,000 to 108,000 degrees Fahrenheit, more than ten times hotter than the surface of our Sun. Now, Reindl and her research team has shown that SAO 245567 is cooling. Reindl speculates the temperature jump was caused by a brief flash of helium fusion that occurred in a shell around the core of the central star. Recently, the star appears to be backstepping into its early stage of stellar evolution.

"We're very lucky to observe it just in that moment," said Reindl. "During such a helium shell flash, it evolves very quickly, and that implies short evolutionary timescales, so we can't usually see how these stars evolve. We just happened to be there at the right time to have caught that."

The team studying the rapid fading of the Stingray nebula can only speculate at this time what's in store for the future of this young nebula. At its present rates of fading, it's estimated the nebula will barely be detectable in 20 or 30 years.

A new machine learning approach offers important insights into catalysis, a fundamental process that makes it possible to reduce the emission of toxic exhaust gases or produce essential materials like fabric.

In a report published in Nature Communications, Hongliang Xin, associate professor of chemical engineering at Virginia Tech, and his team of researchers developed a Bayesian learning model of chemisorption, or Bayeschem for short, aiming to use artificial intelligence to unlock the nature of chemical bonding at catalyst surfaces.

"It all comes down to how catalysts bind with molecules," said Xin. "The interaction has to be strong enough to break some chemical bonds at reasonably low temperatures, but not too strong that catalysts would be poisoned by reaction intermediates. This rule is known as the Sabatier principle in catalysis."

Understanding how catalysts interact with different intermediates and determining how to control their bond strengths so that they are within that "goldilocks zone" is the key to designing efficient catalytic processes, Xin said. The research provides a tool for that purpose.

Bayeschem works using Bayesian learning, a specific machine learning algorithm for inferring models from data. "Suppose you have a domain model based on well-established physical laws, and you want to use it to make predictions or learn something new about the world," explained Siwen Wang, a former chemical engineering doctoral student. "The Bayesian approach is to learn the distribution of model parameters given our prior knowledge and the observed, often scarce, data, while providing uncertainty quantification of model predictions."

The d-band theory of chemisorption used in Bayeschem is a theory describing chemical bonding at solid surfaces involving d-electrons that are usually shaped like a four-leaf clover. The model explains how d-orbitals of catalyst atoms are overlapping and attracted to adsorbate valence orbitals that have a spherical or dumbbell-like shape. It has been considered the standard model in heterogeneous catalysis since its development by Hammer and Nørskov in the 1990s, and though it has been successful in explaining bonding trends of many systems, Xin said the model fails at times due to the intrinsic complexity of electronic interactions.

According to Xin, Bayeschem brings the d-band theory to a new level for quantifying those interaction strengths and possibly tailoring some knobs, such as structure and composition, to design better materials. The approach advances the d-band theory of chemisorption by extending its prediction and interpretation capabilities of adsorption properties, both of which are crucial in catalyst discovery. However, compared with the black-box machine learning models that are trained by large amounts of data, the prediction accuracy of Bayeschem is still amenable to improvement, said Hemanth Pillai, a chemical engineering doctoral student in Xin's group who contributed equally to the study.

"The opportunity to come up with highly accurate and interpretable models that build on deep learning algorithms and the theory of chemisorption is highly rewarding for achieving the goals of artificial intelligence in catalysis," said Xin.

MIAMI--Scientists at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science and Wildlife Computers, Inc. today announced the release of a new activity data product application for marine animal tracking. The technology is designed to remotely track and transmit data gathered on an animal's activity levels over several months along with the temperatures and depths they experienced.

Determining if and how marine animals change their activity levels in response to varying environmental conditions like temperature is important for understanding and predicting their responses to global warming and other environmental changes.

"The new feature available on the Wildlife Computers MiniPAT pop-up tag has an integrated accelerometer for measuring activity, and its onboard software computes a summarized value of overall activity level, which can be transmitted to satellites," said Rachel Skubel, the study's lead author and a Doctoral student at UM's Abess Center for Ecosystem Science & Policy. "The Activity Time Series (ATS) data product allows us to determine when the tagged animal is switching from slow to fast swimming and vice versa."

Wide-ranging ocean species, such as sharks, tunas, and billfish, lead complex lives hidden under the ocean surface. This makes studying activity levels in these species very challenging for scientists. While some tags have integrated accelerometers capable of measuring animal activity levels, the amount of raw data generated is generally too large to transmit via satellite, which required scientists to somehow retrieve the tags and download the accelerometer data. This has been a major limitation for gathering key data on how these species use their environment.

"Along with changes in activity level, the tag also collects and transmits data on the animal's swimming depth and the temperatures they encounter with a user-programmable resolution," said Kenady Wilson, Ph.D. research scientist, Wildlife Computers and a co-author of the study. "These data are transmitted via our MiniPAT (pop-up archival transmitting tag) with a tracking period of up to three months."

This was truly a collaborative effort with the University of Miami and professor Hammerschlag's team," said Melinda Holland, CEO of Wildlife Computers. "This project demonstrates exactly what we do with the research community--design, develop, test, and deliver a tag that meets the project's goals and objectives."

To test the new ATS technology, researchers attached MiniPAT tags to cobia (Rachycentron canadum) housed at the University of Miami's Experimental Fish Hatchery. Using cameras to record the actual behaviors of the tagged cobia, researchers evaluated how changes in activity levels measured and transmitted by the ATS satellite tags matched the actual activity levels of the cobia recorded on camera. To see how well the tag performed in the wild, the team attached MiniPAT tags enabled with the ATS data product to sandbar sharks. After one month, the tags popped off as programed and successfully transmitted the sharks' activity data along with their environmental conditions and locations.

"The ability to now remotely track how animals are behaviorally responding to changes in environmental conditions over several months and across vast expanses of open ocean really opens up a lot of new research opportunities" said Neil Hammerschlag, research associate professor at the UM Rosenstiel School of Marine & Atmospheric Science and UM Abess Center for Ecosystem Science & Policy. "This is especially important for understanding if and how these species respond to climate change"

The study, titled "A scalable, satellite-transmitted data product for monitoring high-activity events in mobile aquatic animals" was published on 22 November 2020 in the journal Animal Biotelemetry.

Autologous chondrocyte implantation (ACI) has been used in adults with deep cartilage defects for over 30 years and has been further developed and modified over time. For the most recent procedure, matrix-induced ACI (M-ACI), favourable effects have been shown suggesting that the benefits are at least comparable to those of therapy alternatives. No advantages are evident for the other two older procedures, collagen-covered ACI (ACI-C) and ACI with a periosteal flap (ACI-P)

This is the conclusion of the final report that the German Institute for Quality and Efficiency in Health Care (IQWiG) has now presented on behalf of the Federal Joint Committee (G-BA). The patient-relevant benefit of all three generations of ACI ¬- ACI-P, ACI-C or M-ACI - was investigated.

Matrix-induced ACI offers technical advantages

ACI has been used in Germany for many years to treat cartilage defects in adults affecting more than 50 percent of the cartilage depth or extending into the underlying bone. Today, M-ACI is the most commonly used technique; according to several comments on the preliminary report, the two older procedures, ACI-C and ACI-P, no longer have any practical relevance.

In the two-stage procedure, cartilage is first removed, cultivated in a laboratory and then implanted into the defect in a second step. In M-ACI, the cultivated cartilage cells are directly fixed on a carrier matrix and reimplanted into the cartilage defect area. This technical progress supersedes the more complex fixation and watertight sealing of a cell suspension in the cartilage defect that is required with the older procedures - in the case of ACI-P using periosteum or in the case of ACI-C using a collagen membrane. Overall, M-ACI makes surgery much easier.

Favourable effects only with M-ACI

Based on a meta-analysis of the study data from seven RCTs, it can be assumed that the M-ACI procedure has a benefit at least comparable to that of therapy alternatives such as microfracturing or mosaicplasty: Statistically significant effects in favour of M-ACI were shown for knee function and health-related quality of life, but were not of a clinically relevant magnitude. The results for other outcomes also suggest almost without exception an advantage of M-ACI, so that overall a benefit for M-ACI at least comparable to the therapy alternatives can be determined.

The two older procedures, ACI-P and ACI-C, consistently produce worse results when examined individually: Based on partly inconsistent results from two RCTs on each procedure, neither a benefit of ACI-C and ACI-P is evident, nor can a comparable benefit to therapy alternatives be determined.

Researchers from the Department of Biochemistry of RUDN University developed a wound-healing gel based on a substance that is produced by Trichoderma fungi. The results of the study were published in the Nov.-Dec. 2020 issue Systematic Reviews in Pharmacy journal.

The best way to treat skin damage is to accelerate cell regeneration using ointments with different active ingredients such as metabolic products of microorganisms. Fungi, bacteria, and other organisms produce antibiotics, enzymes, growth promoters, vitamins, and amino acids, and scientists are always looking for ways to turn them into medicinal drugs. One of these useful substances is L-lysine-oxidase produced by Trichoderma fungi. A team of researchers from RUDN University developed a technology to incorporate this enzyme into a wound-healing gel. The method does not require expensive purification of the initial biological liquids and therefore is economically feasible.

"Modern-day microbiology is focused on physiologically active metabolic products of microorganisms. The fungi of the genus Trichoderma are well-studied, and the Trichoderma harzianum Rifai F-180 strain can produce large quantities of a protein called L-lysine-oxidase that has confirmed antiviral and anti-tumor properties. This opens a range of prospects for the development of new pharmaceutical forms that could be used to treat infections and skin damage," said Prof. Irina Smirnova, a PhD. in Biology, from Berezov Department of Biochemistry at RUDN University.

Based on the results of earlier studies, the team chose the optimal active ingredient concentration of 1%. When selecting additional components for the gel, the scientists followed a set of rules. The base of the gel had to match the active ingredient, support the activity of L-lysine-oxidase, secure easy application and storage, and cause no irritation. Following these principles, the team chose and tested three base options: methylcellulose, carbopol, and mARS.

The experiment was conducted on nine adult guinea pigs divided into groups of three. The skin of the animals was mechanically damaged, and 18 hours after that the team started the treatment. Each animal was treated with one of the three types of gel for two weeks. The product based on methylcellulose demonstrated the worst results with wounds healing for 9 to 10 days on average. The best results were registered in the group that received the carbopol-based gel: the wounds of the animals healed after 6 to 7 days.

"Based on the results of the experiment, we can confirm that 1% carbopol-based gel with the culture liquid of Trichoderma has advanced wound-healing properties. The next stage for us will be a pre-clinical trial. The new pharmaceutical form could be used in veterinary medicine to treat wounds, viral skin infections, and ocular herpes. Moreover, it could find application in medical cosmetology, gynecology, and skin cancer therapy," added Prof. Irina Smirnova from RUDN University.