Tech

The joint research team of RIKEN and Hokkaido University developed a method to predict rate constants of reverse intersystem crossing (RISC)(1) associated with light emission efficiency of organic semiconductors used for Organic Light-Emitting Diode (OLED)(2) through quantum chemical calculations with computers.

Thermally activated delayed fluorescence (TADF) materials have been expected to be the next-generation OLED materials. One of the challenges for the practical application of the materials is development of TADF materials with faster RISC. Our developed method has demonstrated accurate prediction of RISC rate constants for various TADF materials. Organic semiconductors designed based on this prediction method presented high RISC rate constant of 107 per seconds or higher. In the future, with materials informatics studies using the method in combination with machine learning, we would be able to establish theories and scientific principles, which would lead to drastic improvement in efficient virtual screening and device performance of OLED materials.

The research was conducted by Naoya Aizawa and Yong-Jin Pu, researchers at RIKEN Center for Emergent Matter Science (CEMS), Assistant Professor Yu Harabuchi and Professor Satoshi Maeda from Department of Chemistry, Faculty of Science, Hokkaido University and Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University under the research area: Advanced Materials Informatics through Comprehensive Integration among Theoretical, Experimental, Computational and Data-Centric Sciences of the JST the Strategic Basic Research Program PRESTO.

Scientists at UBC are unravelling the mysteries behind a persistent problem in commercial beekeeping that is one of the leading causes of colony mortality--queen bee failure.

This occurs when the queen fails to produce enough fertilized eggs to maintain the hive, and is regularly cited by the Canadian Association of Professional Apiarists as one of the top causes of colony mortality.

In recent research outlined in BMC Genomics, University of British Columbia and North Carolina State University researchers identified specific proteins that are activated in queen bees under different stressful conditions: extreme heat, extreme cold, and pesticide exposure--conditions that can affect the viability of the sperm stored in the honey bee queen's body. If the queen does not have enough live sperm to produce enough fertilized eggs to maintain its population of worker bees, the colony will eventually die out.

Scientists then measured the levels of these markers in a collection of queens in B.C. that had failed in the field, and found that they had higher levels of heat-shock and pesticide protein markers compared to healthy queens. The results pave the way for a future diagnostic test to help beekeepers understand, and prevent, queen bee failure in the future.

"Currently, there isn't any method to actually figure out why the queen has failed in a colony, and that's important because there are quite a few different ways that that could happen," said lead author Alison McAfee, a biochemist at the Michael Smith Labs at UBC and postdoctoral fellow at NC State. "This is a very understudied area."

Previous research conducted by McAfee and her colleagues determined that queens are safest when kept between 15 and 38 degrees Celsius, and identified five protein markers associated with heat-shock in queens. Now, McAfee has confirmed the two most identifiable biomarkers for heat-shock, along with two protein markers useful for detecting cold-shock, and two associated with sublethal levels of pesticides. The findings open the door to testing that will provide beekeepers with information needed to ensure the long-term viability of their hives.

"We want to develop a diagnostic test that we can do on a failed queen, which can provide the beekeeper with information on what happened to her in the past that made her fail now," explained McAfee. "If we can do that reliably, then then the beekeeper could do more to try to prevent that from happening in the future."

Currently, beekeepers simply toss away a failed queen. In the future, said McAfee, "they could ship her to a lab, which would measure the abundance of all these different markers and send a report with information on the likelihood of her being stressed by cause X, Y and Z."

When it came to failed queens from the field in B.C., the researchers were surprised to find elevated markers associated with heat stress and, to a lesser extent, pesticide exposure.

"We didn't have any reason to believe that these queens were heat shocked," said McAfee. "A substantial number of them had elevated levels of those particular markers, which could mean that there is a lot more temperature stress going on out there than we would expect. It could also be that those markers also become elevated due to other kinds of stresses that we haven't looked at yet."

The effect of extreme temperatures on queen bees is a large concern for Canadian beekeepers who import 250,000 queen bees every year, primarily from Australia, New Zealand, and the U.S. Hours spent in the cargo holds of airplanes and warehouses can subject the queens to large fluctuations in temperature during their journey--something McAfee has investigated in past work.

"Every time we put temperature loggers in queen shipments, we have at least some of the shipments coming back is being outside of that Goldilocks zone between 15 and 38 degrees, so I think that happens more frequently than we have been aware of," she said. "There are no rules for shipping queens, such as including temperature loggers in their shipments. Producers just ship them via whatever courier they choose, and beekeepers are at the mercy of the shipper for handling the package properly."

As exploitation of wild fisheries and marine environments threaten food supplies, Flinders University scientists are finding sustainable new ways to convert biowaste, algal biomass and even beached seaweed into valuable dietary proteins and other products.

In one of several projects under way at the Flinders Centre for Marine Bioproducts Development, researchers are looking to extract value from crayfish shells and other marine waste via a 'green' fluidic processing machine developed at the University.

"As world populations grow, so will demand for dietary proteins and protein-derived products and this cannot be met using traditional protein sources," says Professor Kirsten Heimann, who says millions of tonnes of sea catches produce bycatch, shells, bones, heads and other parts wasted during the processing of marine and freshwater species.

Seafood processing by-products (SPBs) and microalgae are promising resources that can fill the demand gap for proteins and protein derivatives, they say in a new publication.

"These biomaterials are a rich source of proteins with high nutritional quality while protein hydrolysates and biopeptides derived from these marine proteins possess several useful bioactivities for commercial applications in multiple industries," adds Flinders University co-author Trung Nguyen in the paper published in Marine Drugs.

"Efficient utilisation of these marine biomaterials for protein recovery would not only supplement global demand and save natural bioresources but would also successfully address the financial and environmental burdens of biowaste, paving the way for greener production and a circular economy."

Value-adding also looks promising with many of the bioactive protein-derived products gaining attention to promote human health including in drug discovery, nutraceutical and pharmaceutical developments. Estimates of the commercial value of these therapeutic protein-based products in 2015 was US$174.7 billion and is predicted to reach US$266.6 billion in 2021, leading to a two-fold increase in demand of protein-derived products.

Globally, 32 million tonnes of SPBs are estimated to be produced annually which represents an inexpensive resource for protein recovery while technical advantages in microalgal biomass production would yield secure protein supplies with minimal competition for arable land and freshwater resources.

This comprehensive review article analyses the potential of using SPBs and microalgae for protein recovery and production critically assessing the feasibility of current and emerging technologies used for the process development.

The nutritional quality, functionalities, and bioactivities of the extracted proteins and derived products together with their potential applications for commercial product development are also systematically summarised and discussed in the free online paper.

The significant reduction in vehicle journeys during the COVID-19 lockdown did not reduce the level of toxic fine particles in Scotland's air, according to experts at the University of Stirling.

Analysis of fine particulate air pollution (PM2.5) in the first month of restrictions found little change - despite a 65 per cent reduction in the number of vehicles on the country's roads.

The team that led the research, from Stirling's Institute for Social Marketing and Health, say their findings suggest that traffic is not a key contributor to outdoor air pollution in Scotland - and, in fact, that people may be at greater risk from air pollution in their own homes.

Dr Ruaraidh Dobson, who led the study, said: "It has been assumed that fewer cars on the road might have led to a decline in the level of air pollution outdoors and, in turn, reduce the number of cases of ill health linked to this pollution. However, our study - contrary to research from places such as Wuhan in China, and Milan - found no evidence of fine particulate air pollution declining in Scotland because of lockdown.

"This suggests that vehicles aren't an important cause of this very harmful type of air pollution in Scotland - and people may be at greater risk from poor air quality in their own homes, especially where cooking and smoking is taking place in enclosed and poorly ventilated spaces."

Road traffic significantly reduced across the world following the introduction of COVID-19 restrictions and research has linked the change to improvements in outdoor air quality in some areas. It has been suggested that this may result in positive health effects.

Dr Dobson and colleague Dr Sean Semple analysed data from 70 roadside monitoring stations around Scotland from March 24 - the day after lockdown was introduced in the UK - to April 23. They then compared the data to comparative 31-day periods in 2017, 2018 and 2019.

They found that, across Scotland, the geometric mean concentration of PM2.5 was 6.6 micrograms per cubic metre of air (μg/m3) in the observed period in 2020 - similar to the levels in 2017 (6.7 μg/m3) and 2018 (7.4 μg/m3).

The 2020 figure was substantially lower than the markedly high concentrations observed in 2019 (12.8 μg/m3), however, the authors pointed out this was an "outlier" likely caused by a meteorological event that caused fine particulate dust from the Saharan desert to impact on UK air quality in April of that year. Significantly, removing the affected period from the 2019 analysis, reduces the mean value to (7.8 μg/m3).

The team did, however, note a reduction in nitrogen dioxide - specifically associated with vehicle exhaust emissions - in 2020, compared to the other three years.

Explaining that personal exposure to potentially harmful air could have actually increased during the lockdown, due to people spending more time at home, the paper says: "Lockdowns are intended to result in people spending more time in their homes. This could increase population exposure to indoor air pollution, such as cooking fumes and second-hand tobacco smoke."

It continues: "In countries, like Scotland, where it appears that the lockdown has not led to reductions in outdoor fine particulate matter pollution, it is possible that personal exposure to PM2.5 may actually have increased rather than declined, due to higher concentrations from indoor sources of particulate within the home setting.

"This could increase adverse health effects overall and also health inequalities - lower income people are more likely to smoke and to smoke indoors, and are likely to have smaller homes leading to higher PM2.5 concentrations from individual sources, due to smaller room volumes.

"If the severity of COVID-19 is related to air pollution exposure - as has been suggested - increased exposure to PM2.5 could potentially increase the death toll of that disease. Careful and balanced consideration of both outdoor and indoor sources of PM2.5 is essential to tackling the health harm of air pollution effectively and equitably."

Skoltech scientists and their colleagues from Lomonosov Moscow State University (MSU) have developed a new method of silicon recycling. Their research was published in ACS Sustainable Chemistry & Engineering.

The majority of solar panels that are produced in ever-increasing quantities use silicon. Solar panels that usually have a service life of 25 to 30 years tend to degrade and produce less electricity over time, making silicon waste recycling a hot-button issue. If we do nothing to recycle silicon waste, our planet will end up cluttered with 60 million tons of used photovoltaic panels by 2050. Converting silicon into silicon oxide nanoparticles has important implications for the environment by dealing with the silicon waste recycling issue and providing a new source of nanoparticles for various uses in science and industry.

A group of researchers led by Stanislav Evlashin, a senior research scientist at the Skoltech Center for Design, Manufacturing and Materials (CDMM), demonstrated a simple and 100% efficient method of converting silicon wafers into nanoparticles in an aqueous solution. This discovery can help find an environmentally friendly way of silicon recycling without using toxic chemicals.

The new controllable conversion process enables controlling the sizes of the nanoparticles which can then be reused in optics, photonics, medicine, and other fields.

"The used panels are converted into nanoparticles using hydrothermal synthesis in an aqueous environment. The good thing about this process is that nanoparticle sizes can be controlled within a range of 8 to 50 nm without using a lot of equipment," explains Evlashin.

The researchers used three types of silicon wafers in the experiment: HR (High resistivity), N-type (Nitrogen-doped), and P-type (Phosphorus-doped). Their theoretical calculations based on the density functional theory showed that the Si-H bonds form on the surface of HR-plates even without using ammonia as a catalyst. The reaction may also be accelerated by using additives, such as phosphorus and boron dopants, and molecular defects (in the case of solar panels).

"The vast majority of methods used to synthesize silicon oxide nanoparticles are based on the bottom-up approach and, therefore, use alkoxides as a precursor. By contrast, ours is a top-down method that uses bulk silicon as a source, which creates a wealth of advantages, such as simplicity, scalability, and controllable particle size distribution. Temperature and hydrolysis time are the key parameters of the synthesis that influence the particle size distribution. We noticed that an increase in pH has a strong effect on the particle formation rate. This is why we used ammonia which made the reaction in an aqueous medium much faster," comments Julia Bondareva, a Skoltech PhD student.

"We decided to figure out how nanoparticles form in the process, among other things. To do this, we used a heterogeneous nucleation model with a finite number of nucleation centers distributed over the silicon source surface," says Timur Aslyamov, a senior research scientist at Skoltech.

Alongside pure silicon, the scientists used industrial solar panels based on the Si-ITO heterostructure which behaved in the same way as silicon panels and were successfully converted into nanoparticles. This research marks a major milestone towards environmentally safe recycling of silicon waste and creating new sources of silicon oxide nanoparticles.

Semiconductor manufacturers are paying more attention to two-dimensional materials, such as transition metal dichalcogenides (TMDs), following the discovery, at KAUST, of an epitaxial growth process of single-crystal TMDs nanoribbons.

An emerging trend in transistor design involves space-saving architectures that stack components on top of one other. TMDs have potential for these systems because they readily form into thin sheets, known as nanoribbons, which have electrical, optical and magnetic activity. However, typical semiconductor processes, such as photolithography, require complicated procedures to produce TMDs of sufficient quality for device purposes.

In collaboration with researchers in the U.S., Belgium and Taiwan, Vincent Tung and colleagues at KAUST are developing alternative approaches to TMD fabrication using surface templates to direct single-crystal growth.

While analyzing candidates with high-resolution electron microscopy, researcher Areej Aljarb spotted something unusual about a semiconductor named gallium trioxide (Ga2O3). After peeling off layers of the flaky material using sticky tape, she saw arrays of narrow, terrace-like ledges that stepped up or down the entire Ga2O3 surface.

"The steps are very steep and well-exposed," says Aljarb. "And because the atoms located near the vicinity of these ledges have asymmetric structures, they can drive growth in specific directions."

When the team exposed Ga2O3 surfaces to a mix of molybdenum and sulfur gas, they observed that TMD nanoribbons crystallized lengthwise along the ledges with structures that were practically defect free. Microscopy experiments and theoretical models revealed that the ledge atoms had unique energetic features that enabled aligned nucleation to form single-crystal nanoribbons. "For decades, scientists have sought to grow 2D single-crystal semiconductors on insulators, and this work demonstrates that controlling the ledges of the substrate is the key," says Tung.

Intriguingly, the nanoribbons could be pulled off and transferred to other substrates without damaging them. To explore potential applications of the ledge-directed growth technology, the international group joined together to design a transistor capable of incorporating nanoribbons from the Ga2O3 template. Electronic measurements showed the new transistor could operate at high speeds and had amplification factors similar to TMD materials produced through more labor-intensive techniques.

"The nanoribbons grow along the ledges using weak physical interactions to stay in place, meaning that no chemical bonds form between the TMD and the underlying Ga2O3 substrate," notes Aljarb. "This unique feature enables us to transfer the nanoribbons onto foreign substrates for many applications, ranging from transistors, sensors, artificial muscles and atomically thin photovoltaics."

Hollow multishelled structures (HoMSs), with relatively isolated cavities and hierarchal pores in the shells, are structurally similar to cells. They can be used as a carrier for antibacterial agent.

A recent research led by Prof. WANG Dan and Prof. ZHANG Suojiang from the Institute of Process Engineering (IPE) of the Chinese Academy of Sciences studied the diffusion and transport mechanism of antimicrobial molecules through HoMSs, and discovered that the unique temporal-spatial order property of HoMSs can realize the sequential drug release for the first time.

This research was published in Nature Communications on Sept. 7.

"We synthesized TiO2-HoMSs through sequential template approach, and introduced antibacterial agent Methylisothiazolinone (MIT) as model molecules into HoMSs," said Prof. WANG.

By analyzing the behavior of HoMSs during drug release, the researchers discovered that the release of the molecules from HoMSs went through sequential release stages, namely burst release, sustained release, and stimulus responsive release.

In detail, by simply adjusting the amount of MIT-HoMSs introduced into the environment, the desired concentration can be quickly reached in the burst release stage due to the MIT molecules absorbed on the outer surface of HoMSs.

The sustained release of MIT molecules in π-π stacked state in the cavity of HoMSs could maintain the required concentration for a long period and inhibit the growth of bacteria.

The triple-shelled HoMS could provide a long sterility period in a bacteria-rich environment that is nearly eight times longer than that of the pure antimicrobial agent under the same conditions.

"When the foreign pathogens were added to our HoMSs system, the driving force was strong enough to break the energy barrier, and the drug molecules stored between the shells and absorbed on the surface were released, resulting in the responsive release. More importantly, the drug concentration can be recovered to the desired range automatically," said Prof. WANG.

Owing to different adsorption characteristics in HoMSs and physical barriers from the multishells, drug molecules in different locations of HoMSs have different release times.

All these advantages could be attributed to chemical diffusion- and physical barrier-driven sequential drug release, providing a route for the design of intelligent nanomaterials.

Dilated cardiomyopathy (DCM) is a leading cause of heart failure, affecting 1 in 250 people. The disease is characterised by an increase in size of the left ventricle of the heart. The stretched heart muscle is then unable to pump blood as effectively, which can lead to irregular heartbeat, heart valve problems, and ultimately heart failure. As the leading cause of heart failure, DCM is the most common reason for carrying out a heart transplant, which is only offered in end-stage heart failure when all other treatment options and lifestyle changes have failed. Despite years of work to improve patient survival after transplantation, the 10-year survival rate is still only 50%.

"Currently DCM is treated with medicines used for heart failure in general, their function being to lower strain on the heart. Patient health would be significantly improved with targeted treatment options prior to the need for a heart transplant," explains Lars Steinmetz, from the European Molecular Biology Laboratory in Heidelberg and Stanford University. "We need therapeutic strategies that target the cause of the disease in a personalised medicine approach." The new study by the Steinmetz group, in cooperation with Mark Mercola's lab at Stanford University, provides fresh insight into this deadly disease, hinting at potential new treatment possibilities.

The researchers had the unique opportunity to study a single family with inherited DCM to understand the cause of their disease. Because it's an inherited disease, studying the genome, or complete set of DNA and genes, can provide important information on the mutation causing the disease. By studying a family, the researchers were able to look for differences in the regions of the genome that carry instructions for making proteins, in family members who had died with a diagnosis of DCM, had been diagnosed with DCM, or were unaffected by DCM. This comparison allowed them to find a single mutation (P633L) in a gene coding for a protein called RBM20, which was disease causing. Although the mutation was previously unknown, changes in RBM20 are known to cause a severe form of inherited DCM that is often associated with early onset of end-stage heart failure.

"When we started the project, we wanted to identify the mutation causing the disease in this family," explains Steinmetz, who is also the founder of the Steinmetz Cardiomyopathy Fund, by which most of the study was financed. Francesca Briganti, from the Mercola Lab, adds: "When we found the new mutation, we had to demonstrate that this is indeed the pathogenic mutation - there were already over 30 genes linked to the disease beforehand. We did this by showing that the mutation causes splicing and cellular contraction defects using in vitro cell models."

The researchers used a combination of patient-derived cells and genome-edited cells. This process of genome editing involved making specific changes to the DNA of the cells, to introduce the RBM20 mutation (P633L) into patient-derived cells known as induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). This gave the researchers the chance to understand how the mutation was causing DCM and also to propose a potential treatment option. "We were lucky. We searched the database and found a fitting compound. Going from finding the disease gene to finding the potential solution overnight was easy with the open databases at EMBL's European Bioinformatics Institute," says Steinmetz.

The team identified a chemical called all-trans retinoic acid (ATRA) as a potential treatment of DCM. ATRA regulates RBM20, and can partially fix the defects in the altered cells. ATRA is a drug used for the treatment of acne and a type of leukaemia called acute promyelocytic leukaemia. In this case, Steinmetz reasoned that increasing expression of RBM20 might overcome the insufficient expression of this protein that is seen in patients who have one functioning and one mutated copy of the gene.

"This is a promising result in approaching RBM20-deficient DCM," explains Steinmetz. "In addition, the general approach and the strategy we used in this study could work for a number of other dominant diseases!"

An isolated population of the rarest Palaearctic butterfly species: the Arctic Apollo (Parnassius arcticus), turned out to be a new to science subspecies with distinct looks as well as DNA. Named Parnassius arcticus arbugaevi, the butterfly is described in a recent paper, published in the peer-reviewed, open-access scientific journal Acta Biologica Sibirica.

"Thanks to the field studies of our colleague and friend Yuri Bakhaev, we obtained unique butterfly specimens from the Momsky Range in North-Eastern Yakutia. This mountain range, which is about 500 km long, has until now been a real 'blank spot' in terms of biodiversity research," explains the lead author of the study, Dr Roman Yakovlev, affiliated with Tomsk State University and Altai State University.

"With the kind permission of Mikhail Ivanov, Director of the Momsky National Park, entomological collections were carried out in various parts of the park. Hard-to-reach areas were visited with the help of inspector Innokenty Fedorov," he adds.

Then, amongst the specimens, the scientists spotted butterflies that at first they thought to be the rarest species for the entire Palaearctic: the Arctic Apollo, a species endemic to Russia and North-Eastern Yakutia, which had only been known from the Suntar-Khayata and Verkhoyansk mountains.

Later, however, the team noticed that the curious specimens were larger on average, had more elongated wings compared to the Arctic Apollo, and were also missing the distinct dark spot on the wings. At that moment, they thought they were rather looking at a species currently unknown to science, and belonging to the Parnassius tenedius species group.

Eventually, following in-depth morphological and molecular genetic analyses, the scientists concluded that the population from the Momsky Range was in fact a new subspecies of the Arctic Apollo and can be distinguished by a number of external and DNA differences. They named the new subspecies Parnassius arcticus arbugaevi after German Arbugaev, Director of the ecological-ethnographic complex Chochur Muran, who provided comprehensive assistance to one of the co-authors of the study, Yu.I. Bakhaev, in his research in Yakutia.

The new subspecies inhabits dry scree slopes with poor vegetation at an elevation of 1,400 m. So far, it is only known from the type locality, Momsky Range, North-Eastern Yakutia, where butterflies can be seen from early June to July. The wingspan in males range between 39 and 45 mm.

"Thus, we obtained significant new data on the distribution and taxonomy of one of the rarest butterflies in the North Palaearctic," say the researchers in conclusion.

TORONTO, September 8, 2020 - Across 5 days in August (3rd-7th), scientists from around the world gathered virtually to present and discuss new information on the role of the chemical senses in disease, nutrition, and social interactions in humans and animals.

The chemical senses, olfaction (smell), gustation (taste), and chemesthesis (touch, temperature, irritation), play essential roles in our daily lives - they serve as important warning systems, alerting us to the presence of potentially harmful situations or substances, including gas leaks, smoke, and spoiled food. Flavors and fragrances are also important in determining what foods we eat and the commercial products we use. The pleasures derived from eating are mainly based on the chemical senses.

Thousands of Americans experience loss or dysfunction of the chemical senses each year resulting from head trauma, sinus disease, cancer, and neurological disorders, such as stroke, multiple sclerosis, and Alzheimer's disease, among others. Indeed, loss of smell and/or taste is a notable and troubling symptom of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has infected millions globally in just the first half of 2020. By providing a better understanding of the function of chemosensory systems, scientific and biomedical research is leading to improvements in the diagnosis and treatment of many disorders.

Among those presenting their research advancements were members of the Association for Chemoreception Sciences (AChemS; http//http://www.achems.org), which held its 41st annual meeting in conjunction with the 2020 International Symposium on Olfaction and Taste (ISOT; https://achems.org/ISOT/). During AChemS/ISOT, scientists from around the world presented their latest research findings on myriad topics around chemosensation, ranging from molecular mechanisms through cognitive processes and associated behaviors.

Selected new discoveries presented at the meeting include:

Understanding the sense of smell via synthetic odors

To study the sense of smell, we generated "synthetic odors" in mice by direct control of brain activity. We measured how mice responded to careful manipulation of artificial odors, discovering that odors are represented by precisely-timed sequences of brain activity akin to timed notes in a melody. https://achems.org/virtual/?page=presentation&session_id=95&presentation_id=294
Contact: Edmund Chong, +1 ?(857) 574-0609, Edmund.Chong@nyulangone.org??

Odors change when we know their names

Odors are invisible, and not always easy to identify. Even so, most people agree on which things smell similar and which are different. Reading the name of an odor while sniffing conjures up a mental image of the odor source and transforms the smell itself.
https://achems.org/virtual/?page=presentation&session_id=95&presentation_id=296
Contact: Sarah Cormiea, +1 (617) 302 0009, sarah.cormiea@gmail.com

The enhanced evolutionary mechanism of olfaction

How did mammals end up with many odorant receptors allowing us to smell thousands of odors? A few highly functional ancestral odorant receptors evolved into numerous less functional receptors that rely on external proteins to function.
https://achems.org/virtual/?page=presentation&session_id=95&presentation_id=247
Contact: Claire de March, +1 (919) 949 8574, claire.de.march@duke.edu

Decreased sense of smell leads to future depression in older US adults

We show for the first time that poor sense of smell predicts the development of depression in older U.S. adults (and not vice versa). These results support mental health screening programs for people with decreased sense of smell.
https://achems.org/virtual/?page=presentation&session_id=94&presentation_id=418
Contact: Jayant M. Pinto, +1 (773) 702-6727, jpinto@surgery.bsd.uchicago.edu

Smelling with single cells: testing the sensitivity limits of olfaction

Using two-photon holographic optogenetics, we showed that mice can reliably detect single spikes across small sets of targeted olfactory bulb neurons. We found that detection performance depends strongly on neuronal synchrony but not on latency relative to inhalation.
https://achems.org/virtual/?page=presentation&session_id=95&presentation_id=289
Contact: Jonathan Gill, +1 (973) 727-5032, jvg219@nyu.edu

Factors Impacting Refreshment

Refreshment is one key reason that consumers enjoy beer, however, there is very limited understanding of impact factors on beer refreshment. This study was aimed to investigate the impact of flavor (citrus, cucumber, lime) and alcohol (0%, 2.5%, 5.0%, 7.5% abv.) on liking and intensity of 12 formulated beers evaluated by 322 participants. The results indicated that refreshing perception was significantly dependent on the likings and intensities of alcohol level and both overall and tested beer flavor.
https://achems.org/virtual/?page=presentation&session_id=94&presentation_id=439
Contact: Amy Hampton, +1 (214) 663- 4016, ahampton4@twu.edu

No differences for liking or taste sensitivity after ultraprocessed and non-processed foods

A randomized, crossover study, twenty participants received ultraprocessed or unprocessed diet for two weeks then two weeks on the other diet. There were no differences in sweet or salt taste measures between the diets. A positive relationship between salt taste preference with blood pressure, body weight, and BMI was observed following the processed diet. The different diets may not initially contribute to changes in taste preference or sensitivity. However, two weeks of a processed diet may be sufficient to detect a relationship between salt taste preference and health parameters.
https://achems.org/virtual/?page=presentation&session_id=94&presentation_id=429
Contact: Paule V. Joseph, +1 (301) 339-4869, Paule.Joseph@nih.gov

Beta-caryophyllene (BCP) improves wound healing in mice

BCP enhanced cell proliferation/migration, suppressed inflammation, and enhanced re-epithelialization. RNA sequencing showed genes related to embryonic growth, cell proliferation/migration, and hair follicle bulge stem cells are up-regulated in response to BCP treatment.
https://achems.org/virtual/?page=presentation&session_id=94&presentation_id=309
Contact: Sachiko Koyama, +1 (812) 345-6155, sakoyama@indiana.edu

A psychological stressor conveyed by appetite-linked neurons

Using single cell RNA-sequencing, retrograde viral tracing, and chemogenetics, we discovered that POMC neurons linked to appetite suppression also play a key role in stress hormone responses to physical restraint, a psychological stressor.
https://achems.org/virtual/?page=presentation&session_id=95&presentation_id=244
Contact: Eun Jeong Lee, 1-425-324-5894. elee2@fredhutch.org

Filiform papillae are "in the thick" of viscosity

Longer filiform papillae or a higher density on the tongue confer sensitivity to viscous solutions. Interestingly, the hard palate is equally responsive, suggesting people may compensate for lack of sensitivity in one tissue by using the other.
https://achems.org/virtual/?page=presentation&session_id=95&presentation_id=214
Contact: Brittany Miles, +1 (919) 656 7090, miles.243@osu.edu

Autism gene affects processing of unfamiliar odors

Autism can produce odor hypersensitivity. A mouse with a gene mutation associated with autism showed deficits in odor identification only with unfamiliar background odors, but not familiar ones. Hypersensitivity occurred only for new odors.
https://achems.org/virtual/?page=presentation&session_id=95&presentation_id=304
Contact: Gonzalo Otazu, +1 (631) 327-5980, gotazual@nyit.edu

Reliable readout of mixture components from small
populations of anterior piriform cortical neurons
Numerous compounds are inhaled in a single sniff. Piriform cortex is central in analyzing mixtures, yet the nature of mixture representations is largely unknown. We show that a simple model accounts for most mixture responses and that individual compounds can be identified from neural activity.
https://achems.org/virtual/?page=presentation&session_id=95&presentation_id=265
Contact: Dan Rokni, +972-2-6757496, dan.ronki@mail.huji.ac.il

Bitter taste receptors (TAS2Rs) mediate food allergy (FA)

Food allergen peptides can stimulate TAS2Rs which may mediate allergy reactions. We observed FA patients have higher bitter taste sensitivity and a lower expression of TAS2Rs than non-FA group, which might cause the failure of allergen tolerance.
https://achems.org/virtual/?page=presentation&session_id=95&presentation_id=260
Contact: Zeping Shao, +61 412 307 229, z.shao@uq.edu.au

Ethanol perception varies with thermal taste status

Thermal tasters report phantom taste sensations simply by having the tip of their tongue warmed or cooled while thermal non-tasters do not and tend to rate intensity of sensations elicited by wine and beer higher than thermal non-tasters. Here, consumers rated taste and mouthfeel sensations from ethanol at levels found in beer, wine, and spirits. Results suggest that thermal tasters experience a wider set of sensations from alcoholic beverages, which may impact their preferences and, ultimately, their alcoholic beverage purchase choices.
https://achems.org/virtual/?page=presentation&session_id=95&presentation_id=222
Contact: Margaret Thibodeau, +1 (905) 688 5550 x4719, mt10xw@brocku.ca

The Life and Death of a Taste Cell

The cells in mammalian taste buds turn over continuously--new cells enter the bud, and old cells die and leave the bud. We examined cell death with detailed images of a mouse taste bud. We found that healthy taste cells might be eating up dying taste cells!
https://achems.org/virtual/?page=presentation&session_id=94&presentation_id=530
Contact: Courtney Wilson, +1 (720) 326-4861, courtney.wilson@cuanschutz.edu

Cranberry polyphenols and individual differences in salivary proteins

Drinking astringent beverages rich in polyphenols can alter salivary protein levels. We tested saliva of subjects after they drank cranberry-derived beverages and found that certain people in the population may have higher levels of key salivary proteins and that this variation is related to bitter taste genetics and gender.
https://achems.org/virtual/?page=presentation&session_id=95&presentation_id=245
Contact: Neeta Yousaf, +1 (914) 309-6161, neeta.yousaf@rutgers.edu

Carbon dioxide (CO(2)) is not just an undesirable greenhouse gas, it is also an interesting source of raw materials that are valuable and can be recycled sustainably. In the journal Angewandte Chemie, Spanish researchers have now introduced a novel catalytic process for converting CO(2) into valuable chemical intermediates in the form of cyclic carbonates.

Getting CO(2) to react is unfortunately not easy. Currently, most research is focused on the conversion of CO(2) into methanol, which can be used as an alternative fuel as well as a feedstock for the chemical industry. Innovative catalytic processes could allow CO(2) to be converted into valuable chemical compounds without taking a detour through methanol, perhaps for the production of biodegradable plastics or pharmaceutical intermediates.

One highly promising approach is the conversion of CO(2) into organic carbonates, which are compounds that contain a building block derived from carbonic acid, comprising carbon atom attached to three oxygen atoms. Researchers working with Arjan W. Kleij at the Barcelona Institute of Science and Technology (Barcelona), the Institute of Chemical Research of Catalonia (Tarragona), and the Catalan Institute of Research and Advanced Studies (Barcelona), have developed a conceptually new process to produce carbonates in the form of six-membered rings, starting from CO(2) and basic, easily accessible building blocks. These cyclic carbonates have great potential for the creation of new CO(2)-based polycarbonates.

The starting materials are compounds with a carbon-carbon double bond and an alcohol group (-OH) on a neighboring carbon atom (homoallylic alcohols). In the first step of the reaction, the double bond is converted into an epoxide, a three-membered ring with one oxygen and two carbon atoms. The epoxide is able to react with CO(2) in the presence of a specific catalyst. The product is a cyclic carbonate in the form of a five-membered ring with three carbon and two oxygen atoms. The carbon atom at the "tip" of the five-membered ring is attached to an additional oxygen atom. In the next step, an organic catalyst (N-heterocyclic base) activates the OH group and causes the five-membered ring to rearrange into a six-membered ring. The oxygen atom from the OH group is integrated into the new ring, while one of the oxygen atoms from the original five-membered ring forms a new OH group. However, the reverse reaction also takes place because the original five-membered ring is significantly more energetically favorable, and only a vanishingly small amount of the six-membered ring is present at equilibrium. The trick is to trap the six-membered ring. The new OH group binds to a reagent (acylation) because its different position makes it considerably more reactive than the original OH group.

This newly developed process gives access to a broad palette of novel, six-membered carbonate rings in excellent yields, with high selectivity and under mild reaction conditions. This widens the repertoire of CO(2)-based heterocycles and polymers, which are difficult to produce by conventional methods.

Physicists from MIPT and the Russian Quantum Center, joined by colleagues from Saratov State University and Michigan Technological University, have demonstrated new methods for controlling spin waves in nanostructured bismuth iron garnet films via short laser pulses. Presented in Nano Letters, the solution has potential for applications in energy-efficient information transfer and spin-based quantum computing.

A particle's spin is its intrinsic angular momentum, which always has a direction. In magnetized materials, the spins all point in one direction. A local disruption of this magnetic order is accompanied by the propagation of spin waves, whose quanta are known as magnons.

Unlike the electrical current, spin wave propagation does not involve a transfer of matter. As a result, using magnons rather than electrons to transmit information leads to much smaller thermal losses. Data can be encoded in the phase or amplitude of a spin wave and processed via wave interference or nonlinear effects.

Simple logical components based on magnons are already available as sample devices. However, one of the challenges of implementing this new technology is the need to control certain spin wave parameters. In many regards, exciting magnons optically is more convenient than by other means, with one of the advantages presented in the recent paper in Nano Letters.

The researchers excited spin waves in a nanostructured bismuth iron garnet. Even without nanopatterning, that material has unique optomagnetic properties. It is characterized by low magnetic attenuation, allowing magnons to propagate over large distances even at room temperature. It is also highly optically transparent in the near infrared range and has a high Verdet constant.

The film used in the study had an elaborate structure: a smooth lower layer with a one-dimensional grating formed on top, with a 450-nanometer period (fig. 1). This geometry enables the excitation of magnons with a very specific spin distribution, which is not possible for an unmodified film.

To excite magnetization precession, the team used linearly polarized pump laser pulses, whose characteristics affected spin dynamics and the type of spin waves generated. Importantly, wave excitation resulted from optomagnetic rather than thermal effects.

The researchers relied on 250-femtosecond probe pulses to track the state of the sample and extract spin wave characteristics. A probe pulse can be directed to any point on the sample with a desired delay relative to the pump pulse. This yields information about the magnetization dynamics in a given point, which can be processed to determine the spin wave's spectral frequency, type, and other parameters.

Unlike the previously available methods, the new approach enables controlling the generated wave by varying several parameters of the laser pulse that excites it. In addition to that, the geometry of the nanostructured film allows the excitation center to be localized in a spot about 10 nanometers in size. The nanopattern also makes it possible to generate multiple distinct types of spin waves. The angle of incidence, the wavelength and polarization of the laser pulses enable the resonant excitation of the waveguide modes of the sample, which are determined by the nanostructure characteristics, so the type of spin waves excited can be controlled. It is possible for each of the characteristics associated with optical excitation to be varied independently to produce the desired effect.

"Nanophotonics opens up new possibilities in the area of ultrafast magnetism," said the study's co-author, Alexander Chernov, who heads the Magnetic Heterostructures and Spintronics Lab at MIPT. "The creation of practical applications will depend on being able to go beyond the submicrometer scale, increasing operation speed and the capacity for multitasking. We have shown a way to overcome these limitations by nanostructuring a magnetic material. We have successfully localized light in a spot few tens of nanometers across and effectively excited standing spin waves of various orders. This type of spin waves enables the devices operating at high frequencies, up to the terahertz range."

The paper experimentally demonstrates an improved launch efficiency and ability to control spin dynamics under optical excitation by short laser pulses in a specially designed nanopatterned film of bismuth iron garnet. It opens up new prospects for magnetic data processing and quantum computing based on coherent spin oscillations.

Species typically evolve over the course of eons, but researchers at the University of Minnesota have developed a way to do it in less than a year. A team of scientists led by Mike Smanski, Ph.D., in the College of Biological Sciences (CBS) has generated speciation events in fruit flies so that engineered strains can reproduce normally with each other, but mating with unmodified flies results in non-viable offspring.

This research, published in Nature Communications, provides the foundations for scientists to be able to prevent genetically modified organisms (GMOs) from reproducing with wild organisms. Additionally, the research will allow scientists to develop new tools to control populations of disease carrying insects and invasive species in a highly targeted fashion.

"Speciation is a fundamental process that drives how life evolves on this planet. Gaining engineering control over speciation will impact our ability to control pests that spread disease, harm crops or degrade the environment," said Smanski, a study author and professor in CBS. "This is one of several new approaches to pest control using modern genome-editing tools to essentially convert the pest organism into the pesticide. Any time our engineered flies attempt to reproduce with wild flies, there are no offspring. This allows it to function like a genetically-encoded birth control for pest organisms."

Their approach, termed Engineered Genetic Incompatibility (EGI), begins by using CRISPR/Cas9 to introduce harmless mutations into regulatory regions of DNA next to those that encode proteins. Scientists then introduce a gene-activator that looks for the original DNA sequence. When the engineered strain reproduces with a wild strain, the offspring will inherit a copy of the original sequence from their wild parent and a copy of the gene-activator from their engineered parent which causes over-activation of the wild gene copy, resulting in non-viable offspring. This method can also be used for transgene biocontainment.

"EGI will prove to be an invaluable tool for the safe use of GMOs. One of the risks of GMOs is the spread of transgenic material into wild populations. However, any genetic components contained within an engineered species are trapped within that species," said study co-author Nathan Feltman, a CBS graduate student in the Smanski Lab.

This research builds on the team's prior work in yeast, which study co-author Siba Das -- a postdoctoral scholar in the Smanski Lab -- states marks a paradigm shift in how scientists look at engineering speciation events and how it is possible that it can be fine-tuned for desired applications.

"Engineering speciation events has been a long standing biotech goal and we are very excited to begin applying this method to major challenges in human and environmental health," said study co-author Maciej Maselko, Ph.D., a Research Group Leader at Macquarie University in Australia.

Rice researchers find potentially useful electrical phenomenon in gold nanowires

HOUSTON - (Sept. 8, 2020) - Though the Summer Olympics were postponed, there's at least one place to see agile hurdlers go for the gold.

You just need a way to view these electron games.

Using a novel optical detection system, researchers at Rice University found that electricity generated by temperature differences doesn't appear to be affected measurably by grain boundaries placed in its way in nanoscale gold wires, while strain and other defects in the material can change this "thermoelectric" response.

The phenomenon could allow for the detection of crystalline defects in conducting materials that are difficult to spot and characterize with even the most advanced microscopic methods.

The result was a surprise to researchers led by Rice physicist Doug Natelson and doctoral alumna Charlotte Evans, now a staff scientist at Sandia National Laboratories, who pursued the explanation after seeing measurements they couldn't explain a few years ago.

"A lot of times, people think about the thermoelectric effect when they're building solar panels or generating power from this or that," Evans said. "We argue instead that the thermoelectric effect is a really interesting diagnostic tool."

The study appears in the Proceedings of the National Academy of Sciences.

Grain boundaries are the planes in materials where misaligned crystals meet, forcing atoms along the edge to adjust as they bind to their neighbors. Measurements in bi-crystal gold nanowires produced by the group of Stanford University electrical engineer and co-author Jonathan Fan showed no detectable effect on thermoelectric voltages at the grain boundary -- the electrons in the metal simply ignored the single grain boundary.

Temperature differences in conductors create thermoelectricity through the Seebeck effect, one type of thermoelectric effect. This effect is commonly used to measure temperature differences and to control thermostats. The Natelson lab triggered the Seebeck effect by heating one portion of Fan's wires with a tightly controlled laser, driving electrons to move from the hot location toward colder regions, and produced a voltage to be measured. No measurable change in the voltage was seen when the laser was moved across the grain boundary in the bi-crystals.

When the laser was moved across parts of the same wires that were deformed, with distortions in the crystal lattice throughout the wire, changes in the voltage became apparent, Natelson said. Annealing the distorted devices partly healed the defects, resulting in clear changes in the thermoelectric current.

"There's a community of people who play around with improving thermoelectric response," Natelson said. "They need to be aware that structural issues like very small distortions to the lattice have effects that are not necessarily small. People tend to ignore these tiny structural issues, but anytime you're making thin-film devices, there's baked-in stress and strain in the material, just because of the way it's made."

Evans said nanoscale crystals are often characterized via electron backscatter diffraction (EBSD), an expensive and time-consuming process. "The benefit of our process is its simplicity," she said. "We use a large spot size from a laser, two microns, which is much larger than the size of an e-beam, and we can detect variations using just a lock-in technique, a scanning laser and a voltage amplifier.

"If you look at the plain EBSD data, it looks as though you have a pristine crystal," she said. "And it's not until you post-process the data and look at how each pixel varies from the next that you would see small distortions along the length of the wire. It's complicated to detect. That's why it's so remarkable that we could detect these little variations with a laser."

"So if you want to do something clever and exploit the thermoelectric response, you need to understand the devices you're making with standard, top-down fabrication methods," Natelson said. "The stress and strain and what seemed like minor structural imperfections can have an easily detectable influence."

In a new study, researchers at Texas A&M University have described their novel plant-based energy storage device that could charge even electric cars within a few minutes in the near future. Furthermore, they said their devices are flexible, lightweight and cost-effective.

"Integrating biomaterials into energy storage devices has been tricky because it is difficult to control their resulting electrical properties, which then gravely affects the devices' life cycle and performance. Also, the process of making biomaterials generally includes chemical treatments that are hazardous," said Dr. Hong Liang, Oscar S. Wyatt Jr. Professor in the J. Mike Walker '66 Department of Mechanical Engineering. "We have designed an environmentally friendly energy storage device that has superior electrical performance and can be manufactured easily, safely and at much lower cost."

Their research is outlined in the June issue of the journal Energy Storage.

Energy storage devices are generally in the form of either batteries or supercapacitors. Although both types of devices can deliver electrical currents when required, they have some fundamental differences. While batteries can store large amounts of charge per unit volume, supercapacitors are much more efficient at generating a large quantity of electric current within a short duration. This burst of electricity helps supercapacitors to quickly charge up devices, unlike batteries that can take much longer.

Supercapacitors have an internal architecture that is more in line with basic capacitors. Both these devices store charge on metal plates or electrodes. However, unlike basic capacitors, supercapacitors can be made in different sizes, shapes and designs, depending on the intended application. Furthermore, supercapacitor electrodes can also be built with different materials.

For their work, Liang and her team were attracted to manganese dioxide nanoparticles for designing one of the two supercapacitor electrodes.

"Manganese dioxide is cheaper, available in abundance and is safer compared to other transition metal oxides, like ruthenium or zinc oxide, that are popularly used for making electrodes," said Liang. "But a major drawback of manganese dioxide is that it suffers from lower electrical conductivity."

Past research has shown that lignin, a natural polymer that glues wood fibers together, used with metal oxides enhances the electrochemical properties of electrodes. However, Liang said there have been few studies looking into combining manganese dioxide and lignin to leverage both of their useful properties.

To create their electrode, Liang and her team treated purified lignin with a commonly available disinfectant, called potassium permanganate. They then applied high heat and pressure to initiate an oxidation reaction that results in the breaking down of potassium permanganate and the deposition of manganese dioxide on lignin. Next, they coated the lignin and manganese dioxide mixture on an aluminum plate to form the green electrode. Finally, the researchers assembled the supercapacitor by sandwiching a gel electrolyte between the lignin-manganese dioxide-aluminum electrode and another electrode made of aluminum and activated charcoal.

Upon testing their newly designed green electrode, they found that their supercapacitor had very stable electrochemical properties. In particular, the specific capacitance, or the ability of the device to store an electrical charge, changed little, even after thousands of cycles of charging and discharging. Also, for an optimal lignin-manganese dioxide ratio, the specific capacitance was observed to be up to 900 times more than what has been reported for other supercapacitors.

Liang noted that these supercapacitors are also very light and flexible. These properties extend their use as structural energy storage elements in vehicles, for example.

"In this study, we have been able to make a plant-based supercapacitor with excellent electrochemical performance using a low-cost, sustainable method," said Liang. "In the near future, we'd like to make our supercapacitors 100% environmentally friendly by incorporating only green, sustainable ingredients."