Tech

The Sun is a magnetized star. Its magnetic field is essentially three dimensional and it occupies all layers of the solar atmosphere. However, routine measurements of the solar magnetic field have only been achieved at the photospheric level, or the solar surface.

Lacking precise knowledge about the magnetic field in the outermost solar atmosphere, the corona, has impeded our understanding of the solar magnetism and many phenomena in the solar atmosphere.

An international team led by TIAN Hui, a professor from both Peking University and National Astronomical Observatories of Chinese Academy of Sciences (NAOC), has measured the global magnetic field of the solar corona for the first time. The study was published in Science on August 7.

The team used observations from the Coronal Multi-channel Polarimeter (CoMP), an instrument operated by the High Altitude Observatory, National Center for Atmospheric Research, USA.

More than 20 years ago, a technique called coronal seismology or magneto-seismology has been introduced for coronal magnetic field measurements. This method makes use of some types of oscillations or waves that are observed in coronal structures.

However, these oscillations/waves are just occasionally observed in small regions of the corona, and thus their potential for magnetic field measurements is limited.

CoMP is a coronagraph with a 20-cm aperture. It can observe the solar corona using the Fe XIII 1074.7 nm and 1079.8 nm infrared spectral lines. The Doppler image sequence obtained from CoMP observations often reveal the prevalence of propagating periodic disturbances, indicating the ubiquitous presence of transverse plasma waves in the corona.

The team applied the magneto-seismology method to these pervasive waves. They extended the previously developed wave-tracking technique to the whole field of view, and obtained the distribution of the wave propagation speed in the global corona.

They also obtained a global map of the coronal density from observations of the two Fe XIII lines. Combing the maps of wave propagation speed and density, they mapped the magnetic field in the global corona.

"By applying this technique to CoMP-like instruments in the future, global coronal magnetic field maps could be routinely obtained, filling in the missing part of the measurements of the Sun's global magnetism," said Prof. TIAN.

Such measurements could provide critical information to advance our understanding of the physical mechanisms responsible for solar eruptions and the 11-year sunspot cycle.

The results of a study conducted by scientists at the University of Turku, Åbo Akademi University, and University of Bristol, show that people who tend to react negatively to rules and recommendations have lower trust in medical doctors and a more negative attitude towards vaccines, or reject vaccines for themselves or their children.

"The vaccine recommendations given by authorities or the social pressure in society to get vaccinated may cause defiance in people who tend to react negatively when they feel that they are forced to do something or that someone is trying to persuade them," says Anna Soveri, Academy Research Fellow at the University of Turku, Finland.

Because of the defiance, people may act contrary to what is expected of them.

"In this case, defiance can lead to scepticism towards medical doctors and negative attitudes towards vaccines, or even vaccine refusal," says Soveri.

Use of Alternative Medicine Quite Common

The study also showed that defiance and low trust in doctors are related to a higher likelihood to use complementary and alternative medicine (CAM). CAM refers to treatments and substances that are not included in evidence-based medicine, meaning treatments and substances for which the efficacy has not been clearly demonstrated through established scientific methods.

In the study, 770 parents of young children were presented with a list of CAM products, from which they were asked to select the ones they had used during the past 12 months to treat an illness or to maintain good health. Almost 40 per cent of the parents reported using one or more CAM products.

"To use complementary and alternative medicine may be a way for people to feel like they are free to make decisions in matters that concern their own health," says Soveri.

High Trust towards Doctors

Half of the parents reported that they had taken the flu vaccine during the preceding season. Approximately 75 per cent of the parents had accepted the childhood vaccines for their children without hesitation, but approximately seven per cent had refused to take a vaccine for their child at least once.

However, most parents expressed high or relatively high trust in doctors.

"For example, nine out of ten parents partly or completely trusted the doctors' ability to make correct diagnoses and that doctors have their patients' best interest in mind when making health-related decisions," tells Soveri.

The parents who participated in the study are part of the FinnBrain Birth Cohort Study at the University of Turku. The FinnBrain research is a birth cohort study with more than 4,000 families. The project was launched at the University of Turku in 2010, and its purpose is to study the combined influence of environmental and genetic factors on child development.

Hydrogels are a class of soft materials resembling native soft tissues, which consist of cross-linked 3D networks formed by covalent bonds or physical interactions. Due to the high water content and viscoelastic nature, hydrogels are well suitable to encapsulate cells and bioactive factors, and therefore extensively investigated for applications in drug delivery and tissue engineering.

The condensation reactions between carbonyl groups (aldehyde, ketone) and N-nucleophiles (primary amine, hydrazide, and aminooxy) undergo spontaneously in physiological conditions, yielding Schiff base, hydrazone, and oxime, respectively, and have been widely used for the construction of hydrogels. The Schiff base is prone to hydrolysis, while the formation of hydrazone and oxime linkages, much more stable than Schiff base, proceeds at second-order rate constants below 0.1 M-1 s-1 at neutral condition. Consequently, the hydrogels based on the carbonyl/N-nucleophile reaction are commonly prepared at relatively high concentration of cross-linking moieties or in the presence of catalysts, giving rise to toxicity issues. Thus, fast and catalyst-free cross-linking strategy is of great significance for the construction of hydrogels for biomedical applications.

Recently, Prof. Xuesi Chen and colleagues at the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, proposed a new crosslinking strategy based on the condensation reaction between o-phthalaldehyde (OPA) and N-nucleophiles for hydrogel formation (Figure 1). When four-arm poly(ethylene glycol) (4aPEG) end-capped with OPA was mixed with various N-nucleophile-terminated 4aPEG as building blocks, hydrogels were formed with superfast gelation rate, enhanced mechanical strength, and markedly reduced critical gelation concentrations (CGCs) as low as 1% (w/v). The CGCs are merely 1/25~1/4 of those for the benzaldehyde-based counterparts, which diminishes the toxicity issue of high aldehyde content. No hydrogel formation (Schiff base) or considerable long gelation time (27~100 min for oxime, acylhydrazone) was observed for the benzaldehyde-based mixtures at 12% (w/v), while free-standing hydrogels could form within few seconds for the OPA-based hydrogels at the same polymer concentration. Besides, the mechanical properties of the OPA-based hydrogels were markedly strengthened (Figure 2).

Small molecule model reactions indicate the key to these cross-links is the rapid formation of heterocycle phthalimidine product or isoindole (bis)hemiaminal intermediates, depending on the N-nucleophiles. The second-order rate constant for the formation of phthalimidine between OPA and methylamine (4.3 M-1 s-1) is over 3000 times and 200 times higher than those reported for acylhydrazone and oxime formation from benzaldehyde in phosphate buffer, respectively, and comparable to many cycloaddition click reactions.

Due to the high efficiency and versatility of OPA/N-nucleophile chemistry, various hydrogels can be readily prepared from naturally derived polysaccharide, proteins, and synthetic polymers with no need of tedious chemical modification by using OPA-terminated 4aPEG as cross-linker. The versatile building blocks provide the hydrogels with tunable biodegradability and bioactivity.

Moreover, biofunctionality is easily introduced to the hydrogels by incorporating amine-bearing peptides via the one-step reaction between OPA and amino group during the crosslinking process. For instance, the c(RGDfK) incorporated hydrogels well supported the adhesion and proliferation of fibroblasts on the hydrogel surface. Taken together, this work provide a universal strategy for the rapid construction of mechanical strengthened and biofunctional hydrogels.

Researchers identify master regulator genes of asthma, provide new path forward in the study of asthma and the development of novel therapies.

Bottom Line: Identification of these master regulator genes provides a new path forward in the study of asthma and the development of novel therapies and treatments.

Results: After identifying nasal gene signatures for mild, moderate, and severe persistent asthma, the researchers applied probabilistic causal methods to identify master regulator genes and validated their results in independent cohorts. Researchers identified (1) a master regulator gene common to asthma across severity and ages (FOXJ1); (2) master regulator genes of severe persistent asthma in children (LRRC23, TMEM231, CAPS, PTPRC FYB); and (3) master regulator genes of mild/moderate persistent asthma in children and adults (C1orf38, FMNL1). The identified master regulators causally regulate the expression of downstream genes that modulate ciliary function and inflammatory response to influence asthma.

How: 156 children were recruited at Mount Sinai Health System in New York with severe persistent asthma as well as controls for nasal transcriptome profiling. Network-based and probabilistic causal methods were applied to identify severe asthma genes and their master regulators. The same approach was then taken in an independent cohort of 190 adults with mild/moderate asthma and controls to identify mild/moderate asthma genes and their master regulators. Comparative analysis of the master regulator genes followed by validation testing in independent children with severe asthma (n=21) and mild/moderate asthma (n=154) was then performed.

Said Mount Sinai's Dr. Supinda Bunyavanich of the research: "Asthma is a common disease that affects people of all ages around the world. We studied nasal samples from children and adults with varying asthma severity not only to identify nasal signatures of mild, moderate, and severe asthma, but also to decipher master regulator genes that causally regulate key biological processes such as inflammatory response and ciliary function that underlie asthma. The master regulators we identified provide a novel path forward for uncovering mechanisms and novel therapy for asthma."

New Haven, Conn. -- A new technique developed by a Yale-led research team improves blood flow in surgically made blood vessels used in dialysis, enables them to last longer, and results in fewer complications than the standard technique.

The findings, based on work with hundreds of patients and supported by animal studies, appear in the August 19 edition of Science Translational Medicine.

Of more than 661,000 Americans with kidney failure, according to the National Institute of Diabetes and Digestive and Kidney Diseases, 468,000 are on dialysis, a method of filtering waste from the blood when the kidneys are damaged or fail. But the standard way of accessing a patient's blood flow has shortcomings the new technique overcomes.

Typically, vascular surgeons fashion a vein-to-artery arteriovenous fistula (AVF) -- a larger, stronger blood vessel -- by dividing a vein in the patient's wrist and joining it to the artery. This enhances blood flow and vein access for the two needles that route a patient's blood through the dialysis machine and back into the body.

Yet the method, standard procedure for the last 50 years, has "the worst results of any procedure we do," said Yale School of Medicine's Dr. Alan Dardik, professor of surgery (vascular) and of cellular and molecular physiology, and senior author of the study.

Sixty percent of fistulas fail to mature, and only 50% are still usable a year later. For women, success rates are even lower, with just 40% of fistulas still usable at one year.

For the many cases in which the fistula can't be maintained, Dardik said, patients need an artificial graft, which has an even lower success rate.

"Eventually these patients can only receive dialysis with a catheter," he said, a procedure that carries increased risk of infection and death. Patients receiving dialysis by catheter have a 1.6 to 2.5 times higher mortality rate than those receiving dialysis by fistulas.

In the new surgical technique, known as radial artery deviation and reimplantation, or RADAR, surgeons essentially reverse the procedure, bringing the artery over to the vein. They also use a tourniquet instead of clamps to temporarily stop blood flow while operating. This requires less handling of the artery and vein than the traditional method and results in better blood flow and a more robust fistula.

"It works a heck of a lot better," said Dardik.

Building on a 2016 pilot study of RADAR's effectiveness involving 53 patients, the new study examined 201 patients who had the novel artery-to-vein surgery and compared them with 73 who had the traditional vein-to-artery surgery.

At one year, 72.2% of the RADAR patients had viable fistulas, compared with 48.1% of traditional fistula patients. At three years, fistulas remained viable in 62.1% of RADAR patients versus 37.6% of patients with traditional fistulas.

Notably, the new procedure was just as successful for female patients as male patients.

The researchers confirmed their findings in animal (rat) studies in which they created both artery-to-vein fistulas and vein-to-artery fistulas, and examined the differences. The results closely mirrored those for the human patients.

The animal studies also made clear why the new technique was more effective. Using CAT scans and ultrasound, researchers observed crucial differences in hemodynamics between the two surgical techniques. "The pattern of blood flow in the RADAR technique was better than the usual pattern of flow with the conventional technique," Dardik said.

Given the significant need for dialysis, Dardik said, the new technique offers a clear opportunity for improving patient outcomes through more robust fistulas and fewer procedures to maintain access and the related complications.

"Surgeons always want the best for their patients," he said, "and the RADAR procedure lets surgeons do their best."

Routing apps such as Google Maps or Nokia's Here platform could offer a cost-effective way of calculating emissions hotspots in real time, say researchers at the University of Birmingham.

These apps routinely capture detailed information as motorists use the GPS technology to plan and navigate routes. This data could be invaluable for researchers and planners who need to better understand traffic flows on busy roads, according to new research published in Weather, the journal of the Royal Meteorological Society.

Current emissions data from road transport is collated from a number of different sources by the National Atmospheric Emissions Inventory and this is fed into annual reports to demonstrate compliance with emissions targets. Many of these traditional air quality models rely on the assumption that traffic is freely flowing at the legal speed limit - whereas in many areas, traffic flow will vary through the day. These models also overlook finer-grained detail from individual roads or junctions that might be emissions hotspots at particular times of the day.

Although more detailed information might be available to city planners when designing new road layouts or traffic improvement schemes, it requires costly modelling by consultancies.

Making use of the crowd-sourced data from routing apps could, the researchers argue, provide a low-cost and highly effective alternative to both high level and localised modelling.

Helen Pearce, a PhD researcher at the University of Birmingham's School of Geography, Earth and Environmental Sciences, led the study. She says: "A lot of guidelines and policy on air quality management are based on hourly time snapshots and on the average amount of traffic on a typical day of the year. The difficulty is that traffic can vary an enormous amount within that time window and along individual roads, so in order to make decisions that really work 'on the ground', we need to be able to access and make use of this finer-grained detail."

The approach suggested by the team was tested on roads in Birmingham's busy city centre. Information on the time taken to travel a series of road links was obtained via a map provider's API (application programming interface). This is conceptually similar to the approach that an individual would take to calculate the time of a journey, but using the API the researchers were able to obtain information for multiple roads and at multiple times of the day.

Following a successful preliminary study, the team scaled up their trial to include 920 major road links across Birmingham city centre, extracting information about these roads at hourly intervals. The researchers found they were able to clearly demonstrate the changes in traffic flow between typical weekdays, weekends, and also the effects of specific social events.

Speed related emissions could then be calculated using a combination of sources including Defra's speed-related emission function database, and traffic count data from the Department of Transport. This information also helped the researchers take into account the relative splits between petrol and diesel engines.

"Our approach could provide significant insights into real-world vehicle behaviours," says Dr Zhaoya Gong, corresponding author on the study. "As we start to see more electric and hybrid vehicles on the road, the emissions picture starts to get more complicated because there will be less exhaust emissions, but we will still see pollution from brakes, tyres and road surface wear - all these will vary significantly according to the speed of the vehicle so this sort of data will be vital for developing accurate emissions models."

CLEMSON, South Carolina - Three teams of researchers at Clemson University have joined forces to unravel some of the mysteries surrounding perovskite nanocrystals, which are semiconductors with numerous applications, including LEDs, lasers, solar cells and photodetectors.

A research article titled "The correlation between phase transition and photoluminescence properties of CsPbX3 (X=Cl, Br, I) perovskite nanocrystals" recently appeared in Nanoscale Advances, an open-access journal published by the Royal Society of Chemistry. The article's lead author is Jun Yi, who was a student working with Apparao Rao, the Robert Adger Bowen Professor of Physics at Clemson University.

"We are always on the hunt for students to work on projects," said Rao, a professor in the College of Science's department of physics and astronomy and director of the Clemson Nanomaterials Institute. "Jun started this project about a year ago, and our teams worked together and ended up with a nice piece of work. In fact, the journal featured our work on its back cover."

Rao said that Yi was able to be liaise between Rao's team and a team led by Jianbo Gao, assistant professor of physics and astronomy; and a third team, led by Hugo Sanabria, an associate professor of physics and astronomy.

Rao and Gao explained that their joint interests in the tiny nanocrystals are focused on the material's optical properties and applications.

"Jianbo's team and my team have a joint interest in advancing nanocrystals to produce better solar cells, LEDs - things like that," Rao said. "Basically, the three teams had the necessary instrumentation to complete the study."
The study has relevance to applications that have already found their way into our lives, according to Gao.

"This technology is widely used. For example, you can find it at Costco or Walmart as it is present in the quantum dots that Samsung uses in its QLED TV," Gao said.

The authors noted in the paper that perovskite nanocrystal are "attracting much attention because of their unique tunable optical properties."

With these particular nanocrystals, the teams' research dealt with a phase transition, one of the most fundamental physical phenomena in solid-state physics, which can influence the electrical, optical, magnetic, mechanical and chemical properties of materials. Using nanocrystals made up, in part, of either chlorine, bromine or iodine, the researchers discovered that, when exposed to heat, the chlorine-based nanocrystals behaved differently than the iodide- or bromine-based nanocrystals.

"That got us thinking about what the reason could be," Rao said.

The paper concluded that the teams' research provides "a deeper insight into the effect of phase-transition on the low temperature photo-physics of perovskite materials."

"We laid out the groundwork and connected the dots," Gao said.

Ironically, the paper wasn't finished until Yi had returned to his home in China.

"We were stumped for some time," Gao said.

"Without this student, we couldn't have achieved this research project. He elevated the level of the paper," Rao added.

In a paper published in NANO, researchers from Shanghai Normal University, China prepared organophilic carbon nanodots (CNDs) using natural organic molecules in plant leaves by a one-pot green synthesis. The multi-emissive carbon dots were used as an efficient fluorescent sensor in ethanol, which have potential applications in sensing fields or energy devices.

Organophilic carbon nanodots (CNDs) were synthesized in acetone from organic extract of natural plant leaves. The CNDs showed multi-band emission, and could be well dispersed in acetone and ethanol. Taking advantage of their structural and optical properties, the CNDs were used as a ratiometric and colorimetric sensor for curcumin detection in ethanol.

Multi-band emission is one of the intriguing properties of the CNDs. In this work, the biomass-derived CNDs showed two photoluminescence (PL) bands. The PL at 520 nm was excitation-independent, while the PL in the blue region could be tuned from 420 nm to 480 nm through changing of the excitation wavelength. Taking advantage of their optical properties, the CNDs were used as a ratiometric and colorimetric sensor for curcumin detection in ethanol. The blue PL of the CNDs at 420 nm was quenched by curcumin through inner filter effect. Meanwhile, the green PL at 495 and 535 nm were enhanced with additional fluorescence of curcumin. The fluorescence color of the mixed solution changed from blue to yellow, and the detection limit reached 36.7 nM. The sensitive and visual detection of the CNDs probe toward curcumin showed their high potential in practical applications.

While most CNDs reported so far were prepared in water, it is of high demand to develop CNDs that can be well dispersed in organic solution. Natural plant leaves contain plenty of organic molecules, their aliphatic groups may be reserved during the formation of the CNDs, and act as surface groups to realize hydrophobicity of the obtained CNDs. Here, the CNDs were directly synthesized in acetone containing organic extract of plant leaves, and could be well-dispersed in acetone and ethanol. This work provided a possible way for changing surface groups of the CNDs by selecting the raw materials.

This work was supported by National Natural Science Foundation of China (No. 61904108; 31900260) and Chenguang Program" (No. 19CG50) by Shanghai Education Development Foundation and Shanghai Municipal Education Commission. The authors would like to thank Dr. Xiaofeng Xu for providing the plant leaves, and thank Dr. Jianwen Yang for the funding and opportunity to finish this work.

Chronic stress increases a blood-based hormone called acyl-ghrelin for years after the initial traumatic stressor exposure in some adolescents, and those with elevated levels of the hormone are more likely to develop post-traumatic stress disorder (PTSD) and to experience more severe cases of the condition, according to a study conducted by researchers at the Icahn School of Medicine at Mount Sinai and published August 20 in JAMA Network Open.

Acyl-ghrelin, a blood-based hormone that is released mostly by the gut during times of energy depletion, was originally termed a "hunger hormone," but the Mount Sinai researchers argue that it is more appropriately classified as a stress hormone and that hunger is a form of stress. Acyl-ghrelin may be a "missing link" by which chronic stress produces lasting changes in the brain that enhance the risk for mental illness, they said.

Specifically, the research team found that the odds of developing PTSD were almost eight times higher in trauma-exposed adolescents with moderately elevated acyl-ghrelin, compared to trauma-exposed adolescents with low levels of the hormone. Those with the highest levels of acyl-ghrelin all developed PTSD, and symptom severity was directly related to acyl-ghrelin levels, both in adolescents who met the criteria for PTSD and those who might be considered to have "sub-threshold" PTSD. Though the researchers' measured cortisol, another hormone often thought to mediate the effects of stress in the brain and body, it was acyl-ghrelin alone, rather than cortisol or the combination of both hormones, that explained most of the variability in PTSD symptom severity, suggesting it as an especially potent biomarker of the disorder.

"Previous work from our lab, using rodent models of PTSD, showed that acyl-ghrelin was increased by chronic stress exposure for months after the exposure, and that this increase was responsible for driving changes in the brain that led to excessively strong fear memories in rodents, similar to those observed in humans with PTSD," said Ki Goosens, PhD, Associate Professor of Psychiatry and lead author of the study. "We also previously showed that in adolescent humans, exposure to severe traumatic stressors led to long-term elevation of the hormone, for years after stressor exposure ended. This study extended these previous studies to ask whether the acyl-ghrelin levels observed years after trauma exposure in adolescent humans are related to PTSD risk and severity."

To answer this question, researchers conducted a cross-sectional study on 49 adolescents who had experienced severe trauma and 39 healthy, matched control participants. Children in the trauma group had experienced a terror attack and were injured, or lost a parent, relative or close friend as a result of the attack. Children from the control group had no terror-associated losses or injuries. Acyl-ghrelin and cortisol were measured in blood and saliva samples, respectively, and all participants were administered the PTSD CheckList - Civilian Version, a standardized rating scale for PTSD.

Their observation of an association between acyl-ghrelin and PTSD in adolescents who experienced severe trauma motivates additional research to investigate the mechanisms underlying trauma-induced elevation of the hormone. The researchers suggest that blood banks collecting samples from PTSD patients should use methods that preserve acyl-ghrelin for analysis, as the hormone can be readily measured in small quantities of blood.

"We hope that lowering acyl-ghrelin levels in traumatized humans will reduce the risk and severity of subsequent PTSD. We also believe that stress-induced production of the hormone may also impact other brain circuits that predispose individuals to additional illnesses beyond PTSD," said Dr. Goosens. "In the meantime, measuring levels of the hormone in stress-exposed individuals may identify some of those who are at risk of developing PTSD so that early therapeutic interventions may be initiated to prevent development of the disorder."

LOS ALAMOS, N.M., August 20, 2020--Los Alamos National Laboratory computer scientists have developed a new artificial intelligence (AI) system that may be able to identify malicious codes that hijack supercomputers to mine for cryptocurrency such as Bitcoin and Monero.

"Based on recent computer break-ins in Europe and elsewhere, this type of software watchdog will soon be crucial to prevent cryptocurrency miners from hacking into high-performance computing facilities and stealing precious computing resources," said Gopinath Chennupati, a researcher at Los Alamos National Laboratory and co-author of a new paper in the journal IEEE Access. "Our deep learning artificial intelligence model is designed to detect the abusive use of supercomputers specifically for the purpose of cryptocurrency mining."

Cryptocurrencies, such as Bitcoin, are forms of digital money. Instead of minting it like coins or paper bills, cryptocurrency miners digitally dig for the currency by performing computationally intense calculations.

Legitimate cryptocurrency miners often assemble enormous computer arrays dedicated to digging up the digital cash. Less savory miners have found they can strike it rich by hijacking supercomputers, provided they can keep their efforts hidden. The new AI system is designed to catch them in the act by comparing programs based on graphs, which are like fingerprints for software.

All programs can be represented by graphs that consist of nodes linked by lines, loops, or jumps. Much as human criminals can be caught by comparing the whorls and arcs on their fingertips to records in a fingerprint database, the new AI system compares the contours in a program's flow-control graph to a catalog of graphs for programs that are allowed to run on a given computer.

Instead of finding a match to a known criminal program, however, the system checks to determine whether a graph is among those that identify programs that are supposed to be running on the system.

The researchers tested their system by comparing a known, benign code to an abusive, Bitcoin mining code. They found that their system identified the illicit mining operation much quicker and more reliably than conventional, non-AI analyses.

Because the approach relies on graph comparisons, it cannot be fooled by common techniques that illicit cryptocurrency miners use to disguise their codes, such as including obfuscating variables and comments intended to make the codes look like legitimate programming.

While this graph-based approach may not offer a completely foolproof solution for all scenarios, it significantly expands the set of effective approaches for cyber detectives to use in their ongoing efforts to stifle cyber criminals.

Based on recent computer break-ins, such software watchdogs will soon be crucial to prevent cryptocurrency miners from hacking into high-performance computing facilities and stealing precious computing resources.

The research appeared July 27, 2020 the journal IEEE Access.

Lithium-ion batteries (LIBs) are a common type of rechargeable batteries. Their versatile nature and numerous applications in all sorts of electronic devices--from mobile phones to cars--makes them seem too good to be true. And perhaps they are: recently, there has been an increase in the number of fire-related incidents associated with LIBs, especially during charging, causing serious concerns over their safety. Scientists now know that these incidents can be due to the use of a broken or unauthorized charger. Often, improper use of these chargers and overcharging can lead to the formation of spiky structures on the negative electrode of the battery, called "lithium (Li) dendrites," which penetrate through the barrier between the negative and positive electrodes and cause a short circuit. Thus, looking at exactly how dendrite formation occurs is crucial to improving the safety of LIBs.

Scientists at Okayama University, led by Associate Professor Kazuma Gotoh, recently took a step in this direction, in a new study published in Journal of Materials Chemistry A. They delved into finding the precise mechanism of dendrite formation in LIBs, in an effort to overcome their limitations and make their practical application easier. Dr Gotoh explains, "We wanted to analyze the formation of metal dendrites in secondary (rechargeable) batteries and contribute to improve the safety of batteries."

Previous studies that tried to understand the process of Li dendrite formation were successful to some extent: they revealed that when the battery is in an overcharged state, dendrite formation occurs in the "overlithiation" phase of the battery cycle. But, these experiments were performed ex situ (outside the actual electrochemical environment), and thus the exact time of onset of dendrite formation was not found. In their new study, Dr Gotoh and his team decided to overcome this limitation. They figured that by applying "operando" methods (which replicate the electrochemical environment) to an analytical technique called "nuclear magnetic resonance" (NMR), they can accurately track the Li atoms in the inner structure of materials, which is not possible when using ex situ methods.

Using this technique, the team had previously succeeded in observing the overcharged states of two types of negative electrodes--graphite and hard carbon electrodes--in the overlithiation phase of an LIB. In the new study, they took this to the next level by observing the state of these electrodes during the lithiation and delithiation process (the "charge and discharge" cycle of the battery). Their NMR analysis helped them to track the precise onset time of dendrite formation and Li deposition in the overcharged battery, for both the graphite and hard carbon electrodes. In graphite, they found the Li dendrites form soon after the "fully lithiated" phase of the electrode occurs. In the hard carbon electrode--in contrast--they observed that dendrites form only after "quasimetallic" Li clusters occur in the pores of hard carbon. Thus, the scientists deduced that when the battery is overcharged, the quasimetallic Li cluster formation acts as a buffer for the formation of Li dendrites in hard carbon electrodes. They even applied the same analysis to another type of rechargeable battery, called sodium-ion battery (NIB), and found similar results. Dr Gotoh explains, "We found that some carbon materials having inner pores (such as amorphous carbon) have a buffer effect for the deposition of Li and Na dendrites during overcharging of batteries. This knowledge will play an important role in ensuring the safety of LIBs and NIBs."

By revealing the intricacies of the dendrite formation mechanisms in LIBs and NIBs, Dr Gotoh and his team provide useful insight into their safety. In fact, the scientists are optimistic that their findings can be applied to other types of rechargeable batteries in the future. Dr Gotoh concludes, "Our findings can be applied not only to LIBs and NIBs but also to next-generation secondary batteries such as all solid-state batteries. This is an important step in making their practical application easier."

With the findings of this new study, we can hope that we possibly are one step closer to realizing our dream of truly sustainable energy resources.

Salk Institute scientists have made a major advance in the pursuit of a safe and effective treatment for type 1 diabetes, an illness that impacts an estimated 1.6 million Americans with a cost of $14.4 billion annually.

Using stem cell technology, Salk researchers generated the first human insulin-producing pancreatic cell clusters able to evade the immune system, as detailed in the journal Nature on August 19, 2020. These "immune shielded" cell clusters controlled blood glucose without immunosuppressive drugs in mice once transplanted in the body.

"Most type 1 diabetics are children and teenagers," says Salk Professor Ronald Evans, senior author and holder of the March of Dimes Chair in Molecular and Developmental Biology. "This is a disease that is historically hard to manage with drugs. We hope that regenerative medicine in combination with immune shielding can make a real difference in the field by replacing damaged cells with lab-generated human islet-like cell clusters that produce normal amounts of insulin on demand."

Type 1 diabetes is a lifelong condition that is challenging to manage, even with automated devices that deliver insulin to regulate blood sugar. Transplants of pancreatic beta islets--clusters of cells that make insulin and other hormones--from donor tissue can provide a cure, but require patients to take life-long immunosuppressing drugs, which carry serious risks. For decades, researchers have sought a better way to replenish lost pancreatic cells. Now, device-free transplantation of insulin-producing cells like these brings us a step closer to curing the disease, according to the lab.

In a previous study, the Evans lab overcame an impediment in the field, in which stem-cell-derived beta-like cells produced insulin, but were not functional. The cells did not release insulin in response to glucose, as they were simply under powered, according to Evans. His team discovered a genetic switch called ERR-gamma that when flipped, "turbo-charges" the cells.

"When we add ERR-gamma, the cells have the energy they need to do their job," says Michael Downes, a Salk senior staff scientist and co-author of both studies. "These cells are healthy and robust and can deliver insulin when they sense high glucose levels."

A critical part of the new study was to develop a way to grow beta-like cells in a three-dimensional environment that approximates the human pancreas. This gave the cells an islet-like property. Importantly, the team discovered that a protein called WNT4 was able to turn on the ERR-gamma-driven maturation switch. This combination of steps generated functional cell clusters that mimic human islets: so-called human islet-like organoids (HILOs).

Next the team tackled the complex issue of immune rejection. Normal tissue transplants require lifelong immune suppressive therapies to protect the tissue from being attacked by the immune system; however these therapies also increase the risk for infections. Inspired by the successes of immunotherapy drugs for cancer, the team initially showed that the checkpoint protein PD-L1 protected the transplanted cells. "By expressing PD-L1, which acts as an immune blocker, the transplanted organoids are able to hide from the immune system," says first author Eiji Yoshihara, a former staff scientist in the lab.

Yoshihara then developed a method to induce PD-L1 in HILOs with short pulses of the protein interferon gamma. When transplanted into diabetic mice, these immune-evasive HILOs provided sustained blood glucose control in diabetic mice with healthy immune systems.

"This is the first study to show that you can protect HILOs from the immune system without genetic manipulation," Downes explains. "If we are able to develop this as a therapy, patients will not need to take immune-suppressing drugs."

More research needs to be done before this system can be advanced to clinical trials. The transplanted organoids need to be tested in mice for longer periods of time to confirm that their effects are long-lasting. More work needs to be done to ensure they would be safe to use in humans as well. "We now have a product that could potentially be used in patients without requiring any kind of device," Evans concludes.

An analysis of facial expressions in ancient Mesoamerican sculptures finds that some emotions expressed in these artworks match the emotions that modern U.S. participants would anticipate for each discernible context, including elation, sadness, pain, anger, and determination or strain. For instance, elation was predicted in the context of social touch while anger was predicted in the context of combat. The results support the hypothesis that some emotions conveyed through facial expressions are universal, reinforcing that feelings can be expressed nonverbally in ways that transcend culture. While previous studies have explored cross-cultural similarities and differences in how facial expressions convey emotions, these studies have typically asked people from Eastern or indigenous cultures to match depictions of Western expressions to situations or words in their native language. Such work may be perceived as biased since it treats Western emotional expression as the norm. To circumvent this bias, Alan Cowen and colleagues asked U.S. research subjects to label emotions expressed in ancient American art sculptures, which predated exposure to modern Western civilizations. The researchers combed through tens of thousands of images of Mesoamerican sculptures on museum websites, identifying 63 authentic sculptures that displayed facial expressions within clearly identifiable contexts, such as a smiling mother holding a baby. Next, Cowen et al. digitally separated each sculpture's expression from its context, producing, for example, one image of just the smile and one image of the mother holding the baby, with no expression visible. They asked the U.S. participants to label each image of a sculpture's facial expression with the emotion it depicted, and, separately, to label images of a sculpture's context with the emotion they would expect to see. Sculptures depicting some emotions passed the test of universality, with facial expression labels ("elated," for the mother's facial expression) matching the expectations of participants who only saw the context (an expressionless mother holding a baby). This suggests that emotional expressions can be inferred through universal human themes, such as a mother-child relationship, even without a common language. "We would eventually be interested in replicating this work in other cultures," says Cowen, noting examples of sculpture from ancient Egyptian, Indian, and Chinese cultures that could potentially be analyzed using similar study protocols. "For the time being, we are heavily focused on studying emotional expression in everyday life across many countries, aided by machine learning tools."

Babies that experience low oxygen levels in the womb due to pregnancy complications often go on to develop heart disease in adulthood. A study using sheep has discovered that a specialised antioxidant called MitoQ can prevent heart disease at its very onset. The results are published today in the journal Science Advances.

Genetics, and their interaction with lifestyle risk factors such as smoking and obesity, play a role in determining heart disease risk in adults. But there is also strong evidence that the environment experienced during sensitive periods of fetal development directly influences long-term cardiovascular health - a process known as 'developmental programming.'

Low oxygen in the womb - known as chronic fetal hypoxia - is one of the most common complications in human pregnancy. In a process termed 'oxidative stress,' low oxygen to the developing fetus can cause damage to its heart and blood vessels. Fetal hypoxia can be diagnosed when a scan during pregnancy shows the baby is not growing properly.

"Many people may be predisposed to heart disease as adults because of the low level of oxygen they received in the womb. By providing a specific mitochondria-targeted antioxidant supplement to mothers whose pregnancy is complicated by fetal hypoxia, we can potentially prevent this," said Professor Dino Giussani from the University of Cambridge's Department of Physiology, Development and Neuroscience, who led the study.

Chronic hypoxia is common to many complications of pregnancy. It can be caused by a number of conditions including pre-eclampsia, infection of the placenta, gestational diabetes or maternal obesity.

Oxidative stress largely originates in the cells' mitochondria - the 'batteries' that power our cells - where the processes of respiration and energy production occur. To target mitochondria the Cambridge team used MitoQ, developed by Professor Mike Murphy and his colleagues at the University of Cambridge's MRC-Mitochondrial Biology Unit. MitoQ selectively accumulates within mitochondria, where it works to reduce oxidative stress.

Having established the safety of the treatment, the researchers gave MitoQ to pregnant sheep under low oxygen conditions. They found that the mitochondrial therapy protects against fetal growth restriction and high blood pressure in the offspring as adults. Using chicken embryos they also showed that MitoQ protects against mitochondria-derived oxidative stress.

MitoQ has already been used in a number of human trials, for example it was shown to lower hypertension in older subjects. It is very exciting to see the potential to use MitoQ to treat a baby during a problematic pregnancy and prevent problems arising far later in life. There's still a long way to go before this can be used by pregnant mothers, but our work points to new possibilities for novel treatments," said Professor Murphy, who was also involved in the study.

This is the first time that MitoQ has been tested during sheep pregnancy. Sheep are animals whose cardiovascular development resembles that of a human baby more closely than laboratory rats and mice. Chicken embryos were also used to isolate the direct effects of MitoQ therapy on the embryonic heart independent of any influence on the mother or placenta.

"Our cardiovascular health is influenced by the lifestyle choices we make in adult life, but can also be traced back to the conditions we experienced when developing inside the womb," said Professor James Leiper, Associate Medical Director at the British Heart Foundation.

He added: "This study reveals a plausible way to reduce the future risk of high blood pressure and consequent heart disease in babies from complicated pregnancies. Further research is now needed to translate these findings from animals to humans and identify the most effective time in development to give the MitoQ supplement to 'at risk' babies - whether that's a particular point during pregnancy or soon after birth. Overcoming this next hurdle will enable it to be tested in clinical trials."

Cardiovascular disease is a group of disorders of the heart and blood vessels that can cause heart attacks and strokes. It claims the life of one in three people, and costs the United States and Canada US$130 billion and the United Kingdom over £30 billion every year. The majority of these costs are for treatments that improve outcomes, but do not cure the disease.

There are increasing calls within the public health community to change the focus of cardiovascular disease research from treatment to prevention. By looking at the specific circumstances that increase the risk of developing heart disease, interventions can be made as early as possible rather than waiting until disease has become irreversible.

"If we want to reduce the prevalence of cardiovascular disease, we need to think of prevention rather than a cure. Applying this concept to pregnancy complications, we can bring preventative medicine all the way back into the womb - it's treatment before birth. It completely changes our way of thinking about heart disease," said Giussani.

The evolution of limbs with functional digits from fish fins happened approximately 400 million years ago in the Devonian. This morphological transition allowed vertebrates to leave the water to conquer land and gave rise to all four-legged animals or tetrapods - the evolutionary lineage that includes all amphibians, reptiles, birds and mammals (including humans). Since the nineteenth century several theories based on both fossils and embryos have been put forward trying to explain how this transformation unfolded. Yet, exactly how hands with digits originated from fish fins remained unknown.

An international team of biologists based at the University of Konstanz (Germany), Macquarie University in Sydney (Australia) and the Stazione Zoologica Anton Dohrn in Naples (Italy) has determined how limbs have evolved from fins using embryos of the Australian lungfish (Neoceratodus forsteri) for their study. The Australian lungfish is the closest living fish relative of tetrapods and is often considered a "living fossil" as it still resembles the fishes that were around at the time when the first four-limbed vertebrates began to walk on land. For these reasons the fins of lungfish provide a better reference to study the evolutionary transition of fins into limbs than any other extant fish species.

The team's research, which is reported in the latest issue of Science Advances, shows that a primitive hand is present in lungfish fins but at the same time suggests that the unique anatomy of limbs with digits only evolved during the rise of tetrapods through changes in embryonic development.

Insights from embryonic development: limb "architect" genes

To solve the puzzle of how limbs emerged from fins during evolution researchers have focused on embryonic development. "During embryogenesis, a suite of 'architect' genes shapes an amorphous group of precursor cells into fully grown limbs", explains Dr. Joost Woltering, first author on the study and an assistant professor in the Evolutionary Biology group at the University of Konstanz led by Professor Axel Meyer. The very same "architect" genes also drive fin development. However, because evolutionary changes have occurred in the activity of these genes, the developmental process produces fins in fish and limbs in tetrapods.

To compare this process in fins and limbs, the team studied such "architect" genes in the embryos of the Australian lungfish. "Amazingly, what we discovered is that the gene specifying the hand in limbs (hoxa13) is activated in a similar skeletal region in lungfish fins", explains Woltering. Importantly, this domain has never been observed in the fins of other fish that are more distantly related to tetrapods. "This finding clearly indicates that a primitive hand was already present in the ancestors of land animals".

Developmental patterns: differences and similarities

The lungfish "hand", in spite of this modern genetic signature, only partially resembles the anatomy of tetrapod hands because it lacks fingers or toes. To understand the genetic basis for this difference the team went on to analyse additional genes known to be associated with the formation of digits, finding that one gene important for the formation of fingers and toes (hoxd13 - a "sister gene" to the above-mentioned hoxa13) appeared to be switched on differently in fins.

During tetrapod limb development, the hoxd13 gene is switched on in a dynamic manner. It first becomes activated in the developing pinky finger and then expands all the way throughout the future hand towards the thumb. This process coordinates the correct formation of all five fingers. While Joost Woltering's team observed a similar activation pattern of this gene in lungfish fins, it did not show this expansion but only remained activated in exactly one half of the fin. Additional differences were found for genes that are normally switched off in digits. In lungfish fins these genes remain active, but on the opposite side of the domain where hoxd13 is activated.

Old hypotheses - future directions

"All of this goes to show that while lungfish fins unexpectedly have a primitive hand in common with tetrapods, the fins of our ancestors also needed an evolutionary 'finishing touch' to produce limbs. In this sense it looks as if the hand was there first, only to be complemented with digits later during evolution", says Woltering. One influential hypothesis regarding the evolution of limbs first put forward by early 20th-century palaeontologists Thomas Westoll and William Gregory, and in the 1980s famously developed further by Neil Shubin, postulates that fingers and toes arose through an expansion of the skeletal elements on one side of the fins of the tetrapod ancestor. This inferred expansion of fin elements corresponds exactly to the differences the team found in the expansion of the digit genes between lungfish fins and tetrapod limbs. The team's observations on the activation and deactivation of limb "architect" genes in lungfish fins thus provides evidence in support of this classical transformational model.

In the future, to fully understand what causes this domain to expand, making our limbs so different from fish fins, the researchers plan to conduct further analyses on the development of fins and limbs, using lungfish but also more modern fish species such as cichlids as their embryos are easier to investigate using techniques like CRISPR. "To complete the picture of what happened in our fish ancestors that crawled onto land hundreds of millions of years ago, we really rely on currently living species to see how their embryos grow fins and limbs so differently", concludes Woltering.