Culture

Chocolate is a beloved treat, but sometimes the cocoa beans that go into bars and other sweets have unpleasant flavors or scents, making the final products taste bad. Surprisingly, only a few compounds associated with these stinky odors are known. Now, researchers reporting in ACS' Journal of Agricultural and Food Chemistry have identified the two compounds that cause musty, moldy scents in cocoa -- work that can help chocolatiers ensure the quality of their products.

Cocoa beans, when fermented correctly, have a pleasant smell with sweet and floral notes. But they can have an off-putting scent when fermentation goes wrong, or when storage conditions aren't quite right and microorganisms grow on them. If these beans make their way into the manufacturing process, the final chocolate can smell unpleasant, leading to consumer complaints and recalls. So, sensory professionals smell fermented cocoa beans before they are roasted, detecting any unwanted musty, moldy, smoky or mushroom-like odors. Even with this testing in place, spoiled beans can evade human noses and ruin batches of chocolate, so a more objective assessment is needed for quality control. In previous studies, researchers used molecular techniques to identify the compounds that contribute to undesirable smoky flavors, but a similar method has not clarified other volatile scent compounds. So, Martin Steinhaus and colleagues wanted to determine the principal compounds that cause musty and moldy odors in tainted cocoa beans.

The researchers identified 57 molecules that made up the scent profiles of both normal and musty/moldy smelling cocoa beans using gas chromatography in combination with olfactometry and mass spectrometry. Of these compounds, four had higher concentrations in off-smelling samples. Then, these four compounds were spiked into unscented cocoa butter, and the researchers conducted smell tests with 15-20 participants. By comparing the results of these tests with the molecular content of nine samples of unpleasant fermented cocoa beans and cocoa liquors, the team determined that (-)-geosmin -- associated with moldy and beetroot odors -- and 3-methyl-1H-indole -- associated with fecal and mothball odors -- are the primary contributors to the musty and moldy scents of cocoa beans. Finally, they found that (-)-geosmin was mostly in the beans' shells, which are removed during processing, while 3-methyl-1H-indole was primarily in the bean nib that is manufactured into chocolate. The researchers say that measuring the amount of these compounds within cocoa beans could be an objective way to detect off-putting scents and flavors, keeping future batches of chocolate smelling sweet.

UNIVERSITY PARK, Pa. -- There are hard-to-please customers in almost every industry, with certain people being picky about which clothes, houses and even romantic partners they will consider.

A new series of studies has found that shopper pickiness can go beyond shopping for the "best" option. The researchers define what it means to be "picky" and also developed a scale for measuring shopper pickiness.

Margaret Meloy, department chair and professor of marketing at Penn State, said the findings could help companies devise the best strategies for satisfying their pickier customers.

"If a company knows they have a lot of picky customers, they may need to change the way they reward salespeople or dedicate specific salespeople to their pickiest customers, because picky shoppers have very narrow preferences and they see perceived flaws in products others wouldn't notice," Meloy said. "Alternatively, a company may allow picky shoppers to customize their products to satisfy their idiosyncratic preferences. It's not just about offering the best products, but offering the products that are best for the picky customers."

Meloy added that even the most robust promotional strategies, like offering a free gift with purchase, may fail with picky customers.

Previous research has found that about 40% of people have family or friends they would consider "picky," suggesting the trait is common. The researchers said it might be helpful for retailers to have a better understanding of what being "picky" means for their customer base, and what those customers may need from a product or shopping experience.

Meloy said that while pickiness affects a customer's shopping habits and therefore affects a company's business, there hasn't been much research done on defining pickiness or investigating how it influences a customer's behavior.

"In marketing, we call customers who want the absolute best version of a product 'maximizers,'" Meloy said. "But with picky customers, the best is more idiosyncratic. For them, it might not be about getting the best quality, but getting the precise version of a product they have in their head -- a shirt in a very precise shade of black, for example. We wanted to explore this a bit more."

For the paper -- recently published in the Journal of Consumer Psychology -- the researchers performed a series of studies to create a scale for measuring shopper pickiness and to identify the consequences of that pickiness on customer behavior.

The first series of studies focused on developing the scale. The researchers said they created a series of questions that would help uncover the psychological dimensions of pickiness while also avoiding using the word "picky," since the word tends to have negative connotations. Once the researchers were confident the scale accurately measured pickiness, they conducted additional studies to examine the possible consequences of pickiness.

The researchers found that people who scored higher on the picky shopper scale tend to have a small window of what they consider acceptable, which the researchers described as having a small latitude of acceptance and a wide latitude for rejection. These shoppers were more likely to reject a free gift when offered as a thank you for participating in a survey.

"This may seem irrational to some people who may not understand why a person would reject things that come at no cost," said Andong Cheng, an assistant professor of marketing at the University of Delaware who earned her doctorate at Penn State. "We speculate that it could be psychologically costly for picky shoppers to take free items that they don't like because possessing these items is a source of irritation for these individuals."

Additionally, the researchers found that picky people didn't change their opinions based on a product's popularity. When they were informed that their top choice of a product was less popular than other options, people who scored high on the picky scale weren't swayed by that information. They stuck with their original selection.

Meloy said the results support the theory that being picky is a general personality trait that isn't just present in one situation or area of a person's life.

"We looked at a range of contexts to see whether being picky in one domain meant you were likely to be picky in others," Meloy said. "Sure enough, individuals who were picky in one domain were picky in other domains. For example, if you tend to be picky while shopping for groceries, you'll probably be picky shopping for clothes, as well."

Meloy said the findings also illustrate the importance of a company understanding and tailoring their business practices to their customer base.

"If you know you have a lot of picky customers, you might not want to bother with offering free products or promoting products by saying how popular they are with other people," Meloy said. "It's just not going to work as well with picky customers. These companies will need to come up with strategies that give customers more control to better align their idiosyncratic preferences with the company's offerings."

Hans Baumgartner, Smeal Chair Professor of Marketing at Penn State, also participated in this work.

In collaboration with VGP, the research group has published a research paper in Nature on platypus and echidna genomes early this year (see report in the right column). In the Nature current special issue, the research group published another study on the genome of the common marmoset, an important primate model for neurodegenerative diseases, drug development and other biomedical research.

The genome includes two sets of chromosomes, one inherited from the mother, the other from the father. In traditional genome sequencing efforts including the human genome project, the sequencing only produced a mosaic reference genome mixing randomly with sequences from the maternal or paternal chromosomes. Now, the research group reported a new strategy to produce completed assemblies of the two sets of genomes independently into chromosomal level. They have applied this method to produce the diploid genomes of a male common marmoset and showed huge number of variations between the two paternal genomes that previous genomic sequencing methods could not obtain. The study has established standards for the new era of biodiversity genomics.

- "The two parental genomes in our cell are not completely identical but have different nucleotide compositions. These differences can affect the function of genes and also our health. Some of these differences in men, for examples, the X chromosome from our mother and Y chromosome from our father have different structures and harbor genes with intensified sexual conflicts," explains Guojie Zhang, the senior author of this study.

The researchers have sequenced a trio (the mother, father and a male offspring) of the common marmosets. Taking advance of the long reads sequencing technology, now the researchers can distinguish the two parental genomic sequences in the male offspring based on the genomic features from the mother and father. For the first time, the researchers present a completed diploid genome with two sets of paternal chromosomes have been assembled independently into chromosome level.

- "This allows us to detect large genomic variations between the parental genomes, " says Chentao Yang, who is a BIO-BGI joined PhD student and the first author of this paper, 'surprisingly, we found the heterozygosity level in the diploid genome is 10 times higher than that can be revealed by previous method'.

The completed assembly also allows the researchers to closely investigate the structure and evolution of the sex chromosomes in this primate species. This New World Monkey species has different structure of sex chromosome than our human. A lineage-specific inversion occurred on the Y chromosome of the common marmoset leading to a more degenerated Y chromosome in this species.

The study also discovered genetic changes occurred in common marmosets that might explain many unique biological traits in this species, such as small body size, high frequency of twin born, gum chewing, and maintaining bone density during aging. Some genes related to the gonadotropin releasing hormone and fertility have accumulated mutations that might provide selection advantage for these animals to produce more twin offspring. The changes on the gonadal estrogen and genes involved in osteoclastogensis and bone metabolism might explain why this primate species does not suffer from osteoporosis during aging because of the reduced level of gonadal estrogen which other primates including human would experience.

CORVALLIS, Ore. - Socially just policies aimed at limiting the Earth's human population hold tremendous potential for advancing equity while simultaneously helping to mitigate the effects of climate change, Oregon State University researchers say.

In a paper published this week in Sustainability Science, William Ripple and Christopher Wolf of the OSU College of Forestry also note that fertility rates are a dramatically understudied and overlooked aspect of the climate emergency. That's especially true relative to the attention devoted to other climate-related topics including energy, short-lived pollutants and nature-based solutions, they say.

"More than 11,000 scientists from 153 countries have come together to warn that if we continue with business as usual, the result will be untold human suffering from climate change," Ripple said. "We have listed six areas, including curbing population growth in the context of social justice, as a framework for action.

"Since 1997, there have been more than 200 articles published in Nature and Science on climate mitigation, but just four of those discussed social justice, and only two considered population," he added. "Clearly social justice and population policy are not getting the attention they deserve in the struggle against the climate emergency."

The Earth's 7.7 billion people contribute to climate change in a variety of ways, primarily through the consumption of natural resources, including non-renewable energy sources, and the greenhouse gas emissions that result from industrial processes and transportation. The more people there are on the planet, the more potential they have for affecting climate.

Partly due to forced sterilization campaigns and China's one-child policy, population policies have long been viewed as a taboo topic and detrimental to social justice, Wolf says, but they can be just the opposite when developed and implemented appropriately with the goal of promoting human rights, equity and social justice.

"There are strong links between high rates of population growth and ecosystem impacts in developing countries connected to water and food security," he said. "Given the challenges of food and water security, effective population policies can support achieving both social justice and climate adaptation, particularly when you consider the current and projected uneven geographical distribution of the impacts of climate change. Policies that address health and education can greatly reduce fertility rates."

Examples of badly needed population policy measures include improving education for girls and young women, ending child marriage and increasing the availability of voluntary, rights-based family planning services that empower all people and particularly poor women, the researchers say.

"Three examples of countries in which improved education for girls and young women may have contributed to significant fertility rate declines are Ethiopia, Indonesia and Kenya," Ripple says. "Among those nations, specific education reforms included instituting classes in local languages, increasing budgets for education and removing fees for attending school. Ethiopia also implemented a school lunch program, large-scale school construction took place in Indonesia, and primary school was lengthened by one year in Kenya."

As part of an overall climate justice initiative, the scientists say, rich countries should do more to help fund voluntary family planning and educational opportunities for girls and young women in developing nations.

"It's not a balanced approach to focus on fertility rates without remembering that wealthy governments, corporations and individuals have been the primary contributors to carbon dioxide emissions and the main beneficiaries of fossil fuel consumption," Wolf said, noting the richest half of the world's population is responsible for 90% of the CO2 emissions.

"From both climate and social justice perspectives, affluent overconsumption by the wealthy must be addressed immediately, for example through policies like eco-taxes such as carbon pricing," Ripple added. "Reducing fertility rates alone is clearly not enough. The middle class and rich must be responsible for most of the needed reduction in emissions."

Taking steps to stabilize and then gradually reduce total human numbers within a socially just framework enhances human rights and reduces the further ordeals of migration, displacement and conflict expected in this century, Wolf and Ripple say. One potential framework is contraction and convergence, which calls for simultaneously reducing net emissions (contraction) while equalizing per capita emissions (convergence). This is equitable in the sense that it entails equalizing per capita emissions globally, a stark contrast to current patterns.

"Social justice and the climate emergency demand that equitable population policies be prioritized in parallel with strategies involving energy, food, nature, short-lived pollutants and the economy," Ripple said. "With feedback loops, tipping points and potential climate catastrophe looming, we have to be taking steps in all of those areas and not ignoring any of them."

Biologists use the term adaptive radiation to describe a phenomenon in which new species rapidly evolve from an ancestral species, often in response to changes in the local environment that lead to new biological niches becoming available. To understand this process, biologists often turn to the cichlids of Lake Victoria, in which over 500 species of the fish have evolved over the past 14,600 years. As Professor Masato Nikaido of Tokyo Tech explains, "The level of genetic differentiation among species is considered very low due to the short period of time after these different species began evolving, and this limited genetic differentiation provides us with a great opportunity to find candidate genes that have contributed to adaptive radiation and the evolution of new species."

Past studies on Lake Victoria cichlids have shown that species living at different depths in the lake differ considerably with respect to the alleles for a gene that determines visual abilities. Spurred by this evidence, Professor Nikaido and his colleagues, including scientists from the Tanzania Fisheries Research Institute, wanted to learn more about the genetic processes underlying adaptation to different environmental conditions. They therefore analyzed the genomes of three species of Lake Victoria cichlids: Haplochromis chilotes and H. sauvagei, which inhabit only rocky shores, and Lithochromis rufus, which inhabits diverse lake-bottom environments, including rocky and sandy areas and areas with vegetation. Their findings are soon to appear in Molecular Biology and Evolution.

Comparisons of genomic data from these different species led to the identification of 678 different genes located within genomic regions that exhibited considerable between-species variation. The researchers saw these genes as potentially playing critical roles in adaptive radiation, and they identified 43 that were specific to H. chilotes, 54 that were specific to H. sauvagei, and 63 that were specific to L. rufus. Some of these genes were related to behavioral variables, such as circadian rhythms, locomotion, and the development of sensory systems.

The genomic analyses also revealed signs of what biologists call "selective sweep events", in which selective pressures cause a beneficial mutation to rapidly increase its frequency within a population and become present in all members of a species. Furthermore, many of the species-specific alleles appeared to have existed alongside several alternative alleles prior to the adaptive radiation that produced different species of fish.

In conclusion, these analyses of Lake Victoria cichlids offer novel insights into the genetic processes underlying adaptive radiation. As Professor Nikaido puts it, "Our analyses uncovered the processes of species-specific adaption of Lake Victoria cichlids and the complexity of the genomic substrate that facilitated this adaptation."

The evidence for species-specific genetic alleles being derived from preexisting genetic variation is a particularly interesting finding that may prove useful to biologists who wish to understand adaptive radiation processes in different environments.

Predatory bacteria--bacteria that eat other bacteria--grow faster and consume more resources than non-predators in the same soil, according to a new study out this week from Northern Arizona University. These active predators, which use wolfpack-like behavior, enzymes, and cytoskeletal 'fangs' to hunt and feast on other bacteria, wield important power in determining where soil nutrients go. The results of the study, published in the journal mBio this week, show predation is an important dynamic in the wild microbial realm, and suggest that these predators play an outsized role in how elements are stored in or released from soil.

Like every other life form on earth, bacteria belong to intricate food webs in which organisms are connected to one another by whom they consume and how. In macro webs, ecologists have long understood that when resources like grass and shrubs are added to lower levels of the web, predators at the top, such as wolves, often benefit. The research team, led by Bruce Hungate and researchers from Northern Arizona University and Lawrence Livermore Laboratory, wanted to test whether the same was true in the microbial food webs found in wild soil.

"We've known predation plays a role in maintaining soil health, but we didn't appreciate how significant predator bacteria are to these ecosystems before now," said Hungate, who directs the Center for Ecosystem Science and Society at Northern Arizona University.

To understand who and how much predator bacteria were consuming, the research team assembled a big picture using dozens of smaller data "snapshots": 82 sets of data from 15 sites in a range of ecosystems. The team used information about how bacteria behave in culture to categorize bacteria as obligate or facultative predators. About seven percent of all bacteria in the meta-analysis were identified as predators, and the majority of those were facultative, or omnivorous.

Obligate predator bacteria like Bdellovibrionales and Vampirovibrionales grew 36 percent faster and took up carbon 211 percent faster than non-predators did. When the soil received a boost of carbon, predator bacteria used it to grow faster than other types. Researchers saw these effects in the omnivorous bacteria, as well, though the differences were less profound.

All the experiments were conducted using a state-of-the-art technique called quantitative Stable Isotope Probing, or qSIP. Researchers used labeled isotopes, which act a little like molecular hashtags, to track who is active and taking up nutrients in the soil. By sequencing the DNA in a soil sample and looking for these labels, the team could see who was growing and eating whom at the level of bacterial taxa.

"While analyzing my data, I noticed that Vampirovibrio was super enriched. Since we know Vampirovibrio is a predator, I became interested in looking for other potential predators in my other data," said Brianna Finley, a postdoctoral research at University of California-Irvine and co-author on the study. "That we could pick up on these signals really validates qSIP as a tool."

Soil ecosystems contain more carbon than is stored in all the plants on Earth, so understanding how carbon and other elements move among soil organisms is crucial to predicting future climate change. And because bacteria are so abundant in soil, they have an enormous role in how nutrients are stored there or lost. And learning more about how predator bacteria act as 'antibiotics' could have therapeutic implications, down the road.

"Until now, predatory bacteria have not been a part of that soil story," said Hungate. "But this study suggests that they are important characters who have a significant role determining the fate of carbon and other elements. These findings motivate us to take a deeper look at predation as a process."

Veterinarians, pet owners and breeders often have preconceived notions about each other, but by investigating these biases, experts at the University of Arizona College of Veterinary Medicine hope to improve both human communication and animal care.

"Veterinary medicine may require us to treat the patient, but we are unable to improve pet patient outcomes without human client consent and trust. Communication is an essential component of veterinary practice," said Ryane Englar, an associate professor and the director of veterinary skills development for the college. "As an anecdotal example, vets and breeders don't always get along, but there was no research on these subjects. I wondered, what do the groups want and need? If they are aligned in any way, how can we work with one another better?"

Englar's most recent study, published in the Journal of the American Veterinary Medical Association, explores biases and communication between vets and breeders. She found that dog and cat breeders often feel that veterinarians lack training and knowledge about birth and breeding. At the same time, vets may not acknowledge breeders' expertise on the subject, and may disapprove of breeding and make assumptions about breeders.

Englar hopes that addressing such biases will help people take better care of animals and each other. She proposes solutions to the tension between pet owners, breeders and vets in her research and in her classes, which focus not only on veterinary skills but on communication skills such as genuine listening, putting judgments on hold, being aware of assumptions and asking questions.

During National Pet Month, UArizona News spoke with Englar about her latest research and her philosophy on animal care and human communication.

Q: Why did you decide to study veterinary medicine communication, and why is it so important?

A: When I attended vet school, classes on communication and professionalism were not required. Historically, it's seen as a soft skill, and something that cannot be taught. In class, it was a sink-or-swim mentality; we were thrown into clinics and expected to just take (medical) history, talk to people, explain diagnoses. I did feel more equipped than peers, though. My mom is a hospice social worker, and my father is a high school teacher; I got my communications training from them. My mom taught me about death and dying and grief and bereavement, so I was well suited to end-of-life talks. But then, communication skills started to get flagged as something that was lacking in the field. It's now seen as a teachable skill, like suturing. Personally, I went from never being taught communication, to asking clients what they want and need to improve communication. At that point, I was proud of the progress, but this research has taught me that I'm still generalizing and approaching some clients with preconceived notions, and that hinders communication and care.

Q: What do pet owners want from their vets when it comes to communication?

A: We teach TONERR to students, which is a method we pieced together from a separate study. It stands for transparency, open-ended questions, nonverbal cues, empathy, reflective listening and unconditional positive regard.

For example, we found that clients want vets to be honest about what they don't know. They expect vets to say, "This is how I can find the information for you." And they expect transparency about diagnoses and prognoses. Don't skirt around things. Clients want to be seen as individuals worthy of respect. We teach students to try and leave their judgment at the door. For example, if a dog owner gives their pet painkillers for a high fever - which you shouldn't do - we'd hope the vet would realize that they likely did it from a good place; they just lacked the knowledge. We'd hope the vet would say, "I can see why you did what you did, but you're here now, so let's focus on that."

Q: As a vet, how did you feel about your latest research findings about communication between vets and breeders?

A: This was one of the most eye-opening studies I've ever done. It taught me a lot about myself. When I read comments from breeders (who participated in the study), some made me feel defensive, but then there was so much that resonated. I hope it helps people think about bridging the divide. If we can understand each other, there's almost perfect alignment from what all parties want and expect. When I surveyed (participants) for solutions, both sides suggested the same things. We just need to get past these biases and actually hear each other.

Here are some examples: Most vets have never seen any dog or cat give birth. Our (pet patient) population is almost all spayed or neutered. It's the assumption that good owners will spay or neuter their pets, and when animals are born, they're born at home and we don't see them until they're eight weeks old. So, when we see an animal that is not spayed or neutered, we wonder why that owner hasn't fixed their pet yet. That makes us have preconceived notions. The reality is that, as vets, we want to be respected for our knowledge and experience; yet, breeders feel they are not being acknowledged for their own knowledge or experience. They've seen hundreds of births, while we've seen close to zero. There needs to be understanding that we each bring different skills to the table.

Q: How has your research affected what you teach in the classroom?

A: Here, at the University of Arizona College of Veterinary Medicine, it is important to me that communication skills have equal consideration in the classroom. My colleague Teresa Graham Brett (the college's associate dean of diversity and inclusion) and I script fictional cases for students. We ask students to consider their expectations before an encounter and compare it to how the encounter actually unfolded, as well as their assumptions about the case, the patient or the client, based on limited details provided upfront. We teach our students that assumptions are normal; it is how we process the world around us and make sense of it. However, we also need students to be aware of how preconceived notions influence their reactions and responses to clinical scenarios, patients and clients. To be successful at relationship-centered care, students need to learn how to move from reaction to response.

Beyond communication, Teresa and I want students to learn to develop their own professional identity, to tactfully practice bad news delivery with clients, to manage the financial and business side of clinical practice and to be resilient in the face of burnout. They might have to euthanize an animal, but we need to teach them how to process their emotions and emotionally reset so they can continue to face appointments after a poor patient outcome.

It's a long journey, but our hope is that we graduate day-one ready students with critical thinking skills, who are able to work with each other and support staff, who are better able to work with clients and really understand themselves in the same way I was open to learning that I have areas to work on after my breeder survey. Medicine is life-long learning and we're all learning together. None of us are perfect, but it's about being a person, first and foremost.

These mysterious earthquakes originate between 400 and 700 kilometers below the surface of the Earth and have been recorded with magnitudes up to 8.3 on the Richter scale.

Xanthippi Markenscoff, a distinguished professor in the Department of Mechanical and Aerospace Engineering at the UC San Diego Jacobs School of Engineering, is the person who solved this mystery. Her paper "Volume collapse instabilities in deep earthquakes: a shear source nucleated and driven by pressure" appears in the Journal of the Mechanics and Physics of Solids.

The term deep-focus earthquake refers to the fact that this type of earthquake originates deep within the Earth's mantle where pressure forces are very high. Since deep-focus earthquakes were first identified in 1929, researchers had been trying to understand what processes cause them. Researchers thought that the high pressures would produce an implosion which would intuitively produce pressure waves. However, they had not been able to connect the dots between the high pressure and the specific kind of seismic waves -- called shear (or distortional) seismic waves -- produced by deep-focus earthquakes. (You can feel distortional energy if you hold your forearm and then twist it.)

In her new paper, Markenscoff completes her explanation of this mystery that occurs under ultra-high pressures. She unraveled the mystery in a string of papers beginning in 2019. In addition, her solution gives insight into many other phenomena such as planetary impacts and planetary formation that share similar geophysical processes.

"This is a perfect example of how deep mathematical modeling rigorously rooted in mechanics and physics can help us solve mysteries in nature. Professor Markenscoff's work can have profound impact not only on how we understand deep-focus earthquakes, but also on how we might controllably use dynamic phase transformations in engineering materials to our benefit," said Huajian Gao, a Distinguished University Professor in Singapore's Nanyang Technological University and the Editor of the Journal of the Mechanics and Physics of Solids where Markenscoff's paper appears.

From transforming rock to earthquake

It has been well recognized that the high pressures that exist between 400 and 700 kilometers below the surface of the earth can cause olivine rock to undergo a phase transformation into a denser type of rock called spinel. This is analogous to how coal can transform into diamond, which also happens deep in Earth's mantle.

Going from olivine to denser spinel leads to reductions in volume of rock as atoms move closer to each other under great pressure. This can be called "volume collapse." This volume collapse and the associated "transformational faulting" has been considered the predominant cause for deep-focus earthquakes. However, until now, there was no model based on volume collapse that predicted the shear (distortional) seismic waves that actually arrive at the earth's surface during deep-focus earthquakes. For this reason other models were also considered, and the state of affairs remained stagnant.

Markenscoff has now solved this mystery using fundamental mathematical physics and mechanics by discovering instabilities that occur at very high pressures. One instability concerns the shape of the expanding region of transforming rock and the other instability concerns its growth.

For the expanding regions of this phase transformation from olivine to spinel to grow large, these transforming regions with large densification will assume a flattened "pancake-like" shape that minimizes the energy required for the densified region to propagate in the untransformed medium as it grows large. This is a symmetry breaking mode which can occur under the very high pressures that exist where deep-focus earthquakes originate, and it is this symmetry breaking that creates the shear deformation responsible for the shear waves that reach Earth's surface. Previously, researchers assumed symmetry-preserving spherical expansion, which would not result in the shear seismic waves. They did not know that symmetry would be allowed to be broken.

"Breaking the spherical symmetry of the shape of the transforming rock minimizes the energy required for the propagating region of phase transformation to grow large," said Markenscoff. "You do not spend energy to move the surface of a large sphere, but only the perimeter."

In addition, Markenscoff explained that inside the expanding region of phase transformation of rock, there is no particle motion and no kinetic energy (it is a "lacuna"), and, thus, the energy that radiates out is maximized. This explains why the seismic waves can get to the surface, rather than much of the energy dissipating in the interior of the Earth.

Markenscoff's analytical model for the deformation fields of the expanding seismic source is based on the dynamic generalization of the seminal Eshelby (1957) inclusion which satisfies the lacuna theorem (Atiya et al, 1970). The energetics of the expanding region of phase transformation are governed by Noether's (1918) theorem of theoretical physics through which she obtained the instabilities that create a growing and fast moving avalanche of collapsing volume under pressure. This is the second discovered instability (regarding growth): once an arbitrarily small densified flattened region has been triggered, under a critical pressure it will continue to grow without needing further energy. (It just keeps collapsing "like a house of cards".) Thus, the mystery is resolved: although it is a shear source, what drives deep-focus earthquake propagation is the pressure acting on the change in volume.

When asked to reflect on her discovery that deep-focus earthquakes could be described with the theorems that are the bedrock of mathematical physics, she said, "I feel like I have bonded to nature. I have discovered the beauty of how nature works. It's the first time in my life. Before it was putting a little step on someone else's steps. I felt this immense joy."

Relevant discovery

The deep-focus earthquakes are only one of the phenomena in which these instabilities manifest themselves. They also occur in other phenomena of dynamic phase transformations under high pressures, such as planetary impacts and amorphization. Today, there are new experimental facilities such as the National Ignition Facility (NIF) managed by Lawrence Liver National Laboratory in which researchers are able to study materials under extremely high pressures that were impossible to test before.

The new work from Markenscoff provides an important demonstration and reminder that gaining deeper understanding of the mysteries of nature often requires the insights that can be gained by harnessing the fundamentals of mathematical physics together with experimental research done in extreme conditions.

In fact, Markenscoff co-organized two National Science Foundation (NSF) funded workshops at UC San Diego in 2016 and 2019 which brought together geophysicists and seismologists with mechanicians to ensure that these research communities remain aware of the methodologies and techniques developed in mechanics.

"Our education systems should continue to invest in the teaching of the fundamentals of science as the pillars for the advancement of knowledge, which can be achieved by interdisciplinary convergence of theory, experiments and data science," said Markenscoff.

She also noted the importance of the research support she has received over the years from the US National Science Foundation (NSF).

"Knowing that my NSF program manager believed that it was possible to solve this 'mystery' and funded me, bolstered both my confidence and my determination to persevere", said Markenscoff. "I point this out as a reminder for all of us. It's also critical that we give thoughtful and considered encouragement to our students and colleagues. Knowing that people whom you respect believe in you and your work can be very powerful."

ARLINGTON HEIGHTS, IL (April 27, 2021) - The American Society of Plastic Surgeons (ASPS) - the world's largest plastic surgery organization, representing nearly 8,000 members - today released the 2020 results of the organization's annual procedure survey coupled with national consumer research reflecting trends during the COVID-19 era to help predict what 2021 will bring.

The Society's board-certified plastic surgeons reported they stopped performing elective surgical procedures for an average of 8.1 weeks in 2020 due to COVID-19, or 15 percent of the year, which mirrors the decline in the total number of procedures performed last year.

ASPS Survey Finds Americans Have More Positive Attitude Toward Plastic Surgery During COVID-19

ASPS recently gauged Americans' perceptions of plastic surgery more than a year into the COVID-19 pandemic, analyzing responses from more than 1,000 women in a national survey fielded by market firm Equation Research, providing insights into how consumers feel about the category, top treatments and their likelihood to pursue a plastic surgery procedure.

During the pandemic, 11% of women surveyed indicated they are more interested in cosmetic plastic surgery or non-surgical procedures now than before COVID-19, and the figure is even higher among women who have already had surgery or a procedure - 24%, respectively. Also, 35% of women who have previously had at least one cosmetic surgical procedure or minimally invasive procedure plan to spend significantly or somewhat more on treatments in 2021 than in 2020.

"For more than a year, COVID-19 has largely confined people to their homes during quarantine and significantly impacted nearly every aspect of their lives," says Lynn Jeffers, MD, MBA, FACS. "The pandemic isn't over, but thanks to vaccines, a new normal is starting to define itself - and some surgeons' offices that were closed or offered only limited services within the last year are seeing higher demand."

Upping the Ante on Body Enhancement

While the first wave of pandemic demand saw a rush on facial procedures in response to a significant surge in Zoom calls and downtime for discreet recovery at home, the national survey results show that tummy tucks (22%) and liposuction (17%) are among the top procedures that women who are extremely or very likely to consider procedures within six months are seeking. The reason is attributed to weight fluctuation during quarantine, and more time to consider procedures long delayed due to time or cost.

ASPS 2020 Top Procedures

Top 5 Cosmetic Surgical Procedures

While ASPS saw an overall 15% decrease in total number of cosmetic procedures in 2020 due to the COVID-19 pandemic, the dip is largely on par with the amount of time practices were closed - and three of the top 5 procedures focused on the face.

The Top 5 cosmetic surgical procedures performed in 2020 were:

1. Nose reshaping (352,555 procedures)

2. Eyelid surgery (352,112 procedures)

3. Facelift (234,374 procedures)

4. Liposuction (211,067 procedures)

5. Breast augmentation (193,073 procedures)

Top 5 Cosmetic Minimally Invasive Procedures

In 2020, minimally invasive cosmetic procedures decreased slightly more than surgical procedures (16% vs. 14%) during stay-at-home orders, dropping for the first time in four years.

Injectables continued to be the most sought-after treatments in 2020. ASPS member surgeons cited a significant uptick in demand during the coronavirus pandemic with current patients eager to reschedule missed neurotoxin and filler appointments, and new patients motivated for the first time to pursue the minimally invasive facial treatments they'd been considering - some even before last March.

Among the 13.3 million cosmetic minimally invasive procedures performed in 2020, the top 5 were:

1. Botulinum toxin type A (4.4 million procedures)

2. Soft tissue fillers (3.4 million procedures)

3. Laser skin resurfacing (997,245 procedures)

4. Chemical peel (931,473 procedures)

5. Intense Pulsed Light (IPL) treatment (827,409 procedures)

Top 5 Reconstructive Procedures

Nearly 7 million reconstructive procedures were performed in 2020, up 3% overall compared to 2019, despite the global pandemic's impact on elective surgeries. Tumor removal is by far the most common reconstructive plastic surgery procedure with approximately 5.2 million procedures performed.

The Top 5 reconstructive procedures performed in 2020 were:

1. Tumor removal (5.2 million procedures)

2. Laceration repair (386,710 procedures)

3. Scar revision (263,643 procedures)

4. Maxillofacial surgery (256,085 procedures)

5. Hand surgery (206,928 procedures)

"While many reconstructive procedures were prioritized as COVID-19 restrictions eased across the country, I'm encouraged that the Society's members were able to quickly attend to patients in need of these surgeries - ranging from burn and wound care to migraine to pediatric craniofacial procedures - to improve their quality of life," says ASPS President Joseph E. Losee, MD, FACS, FAAP.

Although not within the top five, breast reconstruction (137,808 procedures) saw a significant 29 percent year-over-year jump, a greater increase than any of the top five reconstructive procedures.

"A major concern at the onset of the COVID-19 pandemic was continuing care for reconstructive patients," said Dr. Losee. "Despite the year's challenges, patients and care teams were not only able to move forward with procedure plans when deemed safe to do so, but, in terms of breast reconstruction, more women than ever are benefiting from today's technologies and treatments."

Visit plasticsurgery.org/connect for patient safety tips, procedure information, to find a surgeon and book a consultation.

Tokyo, Japan - Human T-cell lymphotropic virus type-1 (HTLV-1) is a retrovirus similar to human immunodeficiency virus (HIV) and has mostly been thought to be transmitted vertically (mother-to-child), or horizontally (sexually or parenterally (e.g. via blood transfusion)). The spread of this infection in metropolitan areas such as Tokyo is presumed to be due to horizontal transmission, especially sexual transmission.HTLV-1-associated diseases are thought to be caused mainly through vertical transmission. In a new study, clinicians from Tokyo Medical and Dental University (TMDU) describe that horizontal transmission route is responsible for HTLV-1 associated disease, i.e. HTLV-1 uveitis.

The clinicians saw a 57-year-old woman who presented with sudden blurred vision. An eye examination revealed profound pathologies in different anatomical locations of her eyes. Most prominent were cellular infiltrates and opacity in the vitreous body, a large gel-like substance between the lens and the back of the eye. Because the pathologies were consistent with uveitis and an inflammation of the eyes, and given the patient's age, the clinicians tested her for the presence of several autoimmune diseases, such as rheumatoid arthritis and sarcoidosis, because uveitis can be a result of those. The tests didn't reveal anything, so the clinicians tested the patient for a number of infectious diseases, such as HTLV-1 and HIV, that can also cause uveitis. When the HTLV-1 test came back positive, the clinicians made their diagnosis of HTLV-1 uveitis.

"HTLV-1 can cause adult T-cell lymphoma, myelopathy and uveitis, among other disorders," says senior author of the study Kyoko Ohno-Matsui. "Although we started the patient on the proper treatment, an unanswered question was how did the patient get infected with the virus in the first place."

Because there's no targeted therapy for HTLV-1 infections, the clinicians had to weaken the patient's immune system with corticosteroids, because an over-reacting immune system is thought to cause harm to the patient. The clinicians started the patient on corticosteroid therapy systemically as well as with topical eye drops over 6 weeks. Over the course of the next several months, the patient suffered from several recurrences, so the clinicians started her on a maintenance corticosteroid therapy, i.e. treatment over the course of 8 months. While no recurrences happened in this time period, 18 months after the start of the maintenance therapy, the patient presented with another recurrence, including a retinal detachment, which could lead to permanent blindness. This detachment was managed by ophthalmic surgery and the patient was again started on corticosteroids, this time for 4 years. No recurrences have happened since then and the patients has remained symptom-free.

Interestingly, during follow-up the patient's mother underwent cataract surgery at the same clinic site. Testing for HTLV-1 revealed no infection of the mother, ruling out vertical transmission to the patient. Of note, HTLV-1 can become symptomatic even decades after initial infection.

"In the current environment of increasing HTLV-1 incidence, the existence of horizontal transmission causing HTLV-1 uveitis should be acknowledged as it can result in more severe inflammation than vertical transmission. Thus, physicians should take the route of infection into consideration when providing medical care to patients with HTLV-1-associated diseases." says first / corresponding author of the study Koju Kamoi.

Most conventional molecular diagnostics usually detect only a single disease-related biomarker. Great examples are the PCR tests currently used to diagnose COVID-19 by detecting a specific sequence from SARS-CoV-2. Such so-called singleplex methods provide reliable results because they are "calibrated" to a single biomarker. However, determining whether a patient is infected with a new SARS-CoV-2 variant or a completely different pathogen requires probing for many different biomarkers at one time.

Scientists from the Helmholtz Institute for RNA-based Infection Research (HIRI) and the Julius Maximilians University (JMU) in Würzburg have now paved the way for a completely new diagnostic platform with LEOPARD. It is a CRISPR-based method that is highly multiplexable, with the potential to detect a variety of disease-related biomarkers in just one test.

How LEOPARD works

LEOPARD, which stands for "Leveraging Engineered tracrRNAs and On-target DNAs for PArallel RNA Detection," is based on the finding that DNA cutting by Cas9 could be linked to the presence of a specific ribonucleic acid (RNA). This link allows LEOPARD to detect many RNAs at once, opening opportunities for the simultaneous detection of RNAs from viruses and other pathogens in a patient sample.

The study published today in "Science" was initiated by Chase Beisel, professor at JMU and research group leader at HIRI, and Professor Cynthia Sharma from JMU's Institute of Molecular Infection Biology (IMIB). "With LEOPARD, we succeeded in detecting RNA fragments from nine different viruses,' says Beisel. "We were also able to differentiate SARS-CoV-2 and one of its variants in a patient sample while confirming that each sample was correctly collected from the patient."

Background

CRISPR-Cas9 is principally known as a biomolecular tool for genome editing. Here, CRISPR-Cas9 function as molecular scissors that cut specific DNA sequences. These same scissors are naturally used by bacteria to cut DNA associated with invading viruses. Whether editing genomes or eliminating viruses, Cas9 cutting is directed by guide RNAs. The guide RNAs found in bacteria must pair with a separate RNA called the tracrRNA. The RNA couple then can work with Cas9 to direct DNA cutting.

An unexpected discovery

The tracrRNA was thought to only pair with guide RNAs coming from the antiviral system. However, the Würzburg scientists discovered that the tracrRNA was pairing with other RNAs, turning them into guide RNAs. Cynthia Sharma, Chair of Molecular Infection Biology II at the IMIB and spokesperson of the Research Center for Infection Diseases (ZINF) at JMU was astounded by this discovery: "When we searched for RNAs binding to Cas9 in our model organism Campylobacter, we surprisingly found that we detected not only guide RNAs, but also other RNA fragments in the cell that looked like guide RNAs. The tracrRNA was pairing with these RNAs, resulting in "non-canonical" guide RNAs that could direct DNA cutting by Cas9."

The LEOPARD diagnostic platform builds on this discovery. "We figured out how to reprogram the tracrRNAs to decide which RNAs become guide RNAs," says Beisel. "By monitoring a set of matching DNAs, we can determine which RNAs were present in a sample based on which DNAs get cut. As part of the ongoing pandemic, LEOPARD could allow a doctor to figure out whether the patient is infected with SARS-CoV-2, if it's a unique variant, and whether the sample was correctly taken or needs to be repeated--all in one test."

In the future, LEOPARD's performance could dwarf even multiplexed PCR tests and other methods. "The technology has the potential to revolutionize medical diagnostics not only for infectious diseases and antibiotic resistances, but also for cancer and rare genetic diseases," says Oliver Kurzai, director of JMU's Institute of Hygiene and Microbiology, which provided patient samples for the study.

"The work highlights the excellent collaborative and interdisciplinary research taking place here in Würzburg," says Jörg Vogel, director of IMIB and HIRI, a joint facility of JMU with the Helmholtz Center for Infection Research in Braunschweig. "LEOPARD impressively demonstrates that we can cover the full spectrum of complementary cutting-edge research in Würzburg, from the fundamentals of RNA research to clinical applications."

A combination of remdesivir, a drug currently approved in the United States for treating COVID-19 patients, and repurposed drugs for hepatitis C virus (HCV) was 10 times more effective at inhibiting SARS-CoV-2, the virus that causes COVID-19.

The combination therapy points a way toward a treatment for unvaccinated people who become infected, as well as for vaccinated people whose immunity has waned, for example due to the emergence of virus variants that escape this immune protection.

Four HCV drugs--simeprevir, vaniprevir, paritaprevir, and grazoprevir--in combination with remdesivir boosted the efficacy of remdesivir by as much as 10-fold, the researchers reported today in Cell Reports. The research team included scientists from Icahn School of Medicine at Mount Sinai, the University of Texas at Austin, and Rensselaer Polytechnic Institute (RPI).

Remdesivir targets a range of viruses and was originally developed over a decade ago to treat hepatitis C and a cold-like virus called respiratory syncytial virus (RSV). During the Ebola outbreak, Remdesivir was tested in clinical trials and found to be safe and effective for patients. Early in the pandemic, it was seen as a good therapy for COVID-19 but did not live up to its early promise in studies.

The research team performed protein binding and viral replication studies on SARS-CoV-2, the virus that causes COVID-19, using remdesivir and 10 hepatitis C drugs, some of which are already approved by the Food and Drug Administration.

RPI team had previously identified "striking similarity" between protease structures, or enzymes that are essential for coronaviral replication, in SARS-CoV-2 and HCV. The similarity raised the possibility that existing drugs which bind to and block the hepatitis C protease would have the same effect against SARS-CoV-2.

Using a supercomputer to model how drugs bind to viral proteins, the RPI researchers predicted that the 10 HCV drugs could bind snugly to the SARS-CoV-2 Main protease, named Mpro. In addition, they showed that seven of these drugs actually inhibited the SARS-CoV-2 protease. The research team at Icahn Mount Sinai then tested whether these seven drugs would inhibit SARS-CoV-2 virus replication in monkey and human cells grown in culture. In subsequent experiments the researchers were surprised to find that the four HCV drugs inhibited a different SARS-CoV-2 protease, known as PLpro. This observation proved to be very important. When each of the seven HCV drugs were tested in combination with remdesivir, only the four drugs that unexpectedly targeted PLpro boosted the efficacy of remdesivir, by as much as 10-fold.

Adolfo Garcia-Sastre, PhD, one of the authors on the paper, Irene and Dr. Arthur M. Fishberg Professor of Medicine. and Director of the Global Health and Emerging Pathogens Institute at Icahn Mount Sinai, said, "Combined use of remdesivir with PLpro inhibitors for the treatment of COVID-19 could be a game changer for patients with COVID-19 who are not vaccinated. It could also reduce the possibility of selecting SARS-CoV-2-resistant viruses."

"The identification of PLpro as an antiviral target that has a synergistic effect in combination with remdesivir is a very important finding. We hope this work will encourage the development of specific SARS-CoV-2 PLpro inhibitors for inclusion in combination therapies to produce a highly effective antiviral cocktail that may potentially prevent the rise of resistance mutations," said Kris White, PhD, Assistant Professor of Microbiology at Icahn Mount Sinai.

"Because these HCV drugs are already approved for use and their potential side effects are known, such a combination therapy could be tested in humans more quickly than for a new drug," said Robert M. Krug, PhD, Professor Emeritus of Molecular Biosciences at The University of Texas at Austin and co-corresponding author of the paper.

One big drawback of remdesivir is that it must be administered intravenously, limiting its use to patients already admitted to the hospital. "Our goal is to develop a combination of oral drugs that can be administered to outpatients before they are sick enough to require hospitalization," said Krug. "The HCV drugs that enhance remdesivir's antiviral activity are oral drugs. It is important to identify oral drugs that inhibit the SARS-CoV-2 polymerase in order to develop an effective outpatient treatment."

"Nearly 3 million people have died worldwide from COVID-19. There are situations where the vaccine isn't the best option and it would be helpful to have orally available antivirals," said Gaetano Montelione, PhD, a member of the Rensselaer Center for Biotechnology and Interdisciplinary Studies (CBIS). "Here we see a promising synergy that, if confirmed through additional research and clinical trials, could provide a new antiviral to combat COVID-19."

The research was conducted at the Department of Food Science at the University of Copenhagen (UCPH FOOD) with professor emeritus Lars Munck as coordinator and builds on earlier work since 1963 at Svaloef Plant Breeding Institute and the Carlsberg Laboratory.

A complete picture of the organism

The research shows how, with the help of a fast, non-destructive and green analysis method, near-infrared spectroscopy (NIRS), we can obtain a global overview that mirrors how the entire chemical composition of nutrients in a barley grain is changed, for example, by a mutation in a single gene. This is in contrast to current conventional plant breeding, where you do not have an overview of all the changes that the barley grain undergoes when a single gene is modified.

Lars Munck and his team have studied barley grains from different barley lines using near-infrared spectroscopy (NIRS). In a split second, this method can provide a "chemical fingerprint" (read more about Near-infrared spectroscopy below) of the barley grains, which describes the chemical-physical composition of the grains, including the nutrients. The researchers analysed the resulting intact spectra by comparing and calibrating them to barley lines of known composition using mathematics (chemometrics).

"We were surprised by the precision that characterises the chemical fingerprints of the grains from the NIRS spectra. At the same time, it surprised us to find that we got the same classification result if we instead used the secondary nutrients/metabolites determined by a more complicated measurement method called gas chromatography mass spectrometry as the chemical fingerprint. Using two different types of analysis with completely different focuses, we arrived at the same classification result," explains Lars Munck and continues:

"This is coherence in a nutshell - all local fingerprints are part of the plant's self-organising network and affect the plant's overall global chemical-physical fingerprints."

One of the barley lines examined was found to have a higher content of the essential amino acid lysine compared to a normal barley. The high content of lysine gives good growth in feeding studies with pigs, but the yield in the field was horrible and with a low starch content.

"By analysing the high-lysine barley lines that were crossed with high starch barley lines bringing high yield, we could use measurements of NIRS fingerprints to select lines with a high content of both lysine and starch, which thus gave higher yields. At the same time, global coherence also allowed us to gain knowledge about the optimal combination of genetic traits for a specific quality purpose," explains Lars Munck, who believes that this is a radical advancement compared to today's plant breeding that is focused on one gene-chemical trait combination at a time.

"With a more holistic approach, allowed by the NIRS method - we can instead examine the chemical fingerprint totality of the different plant lines, and quickly obtain an overview of what material is available and thus target and select lines from the variable crossing pool that are high quality by calibrating to interesting marker lines" says Lars Munck.

Global coherence - the inner self-organisation of the plant

In the discipline of plant breeding, people speak of the genotype, which describes the plant's genetic material, and the phenotype, which describes the traits that can be observed directly or can be measured chemically and thus may be characterised using NIRS.

The approach when using NIRS phenotyping is to change the order of the plant breeding procedure to start by screening the different barley lines for all of their chemical properties represented by fingerprints. This is done by calibrating to known barley lines that have one or more of the desired chemical properties (e.g., high starch content). Only at the end when you have selected the optimal barley line, you make an in-depth determination of the genes that are changed. When searching for an expression for the whole organism, using NIRS fingerprints provides a far more nuanced result, allowing you to examine the overall chemistry of an organism rather than examining each individual gene combination separately. Because coherence guarantees that all fingerprint aspects of an individual communicate you can manage the global composition from very different fingerprint positions.

"With the new method, we have closed the large knowledge gap that exists in the genetics between genotype and phenotype. Now molecular biology will finally have an outlet for its impressive library of primary gene functions, where the result of total contribution of changed genes to a functioning plant can be studied as a whole," says Lars Munck and continues:

"Molecular biology has come up with crucial solutions for genetic diseases, resistance and vaccinations against diseases. But in this success story, we have forgotten that it is not the gene that is the biological unit, but that it is the self-organised individual that uses its inner "calculator" to organize the internal interaction coherence precisely and reproducibly," says Lars Munck.

The researchers call this interaction, which is shown in barley grains using NIRS fingerprints and which they believe can be transferred to all living organisms, global coherence.

"When change occurs in a single or in several of the plant's genes or in the environment, the chemistry and the implicite morphology of the whole organism changes as the plant reorganises itself to obtain a new coherent balance point. This unifying force, coherence, was previously defined in the physics between light beams and atoms in non-living matter and we have now discovered coherence in biology as a macroscopic chemical fingerprint, that we call global coherence. It explains how living matter can replicate itself into recognizable individuals," explains Lars Munck.

The importance of the introduction of macroscopic chemical fingerprint coherence in biology that coordinates physical morphological structures with chemical is a fundamental discovery and highly simplifying complement to molecular genetic indepth understand to gene expression.

Muscle weakness in patients with Becker disease is caused by unusual electrical activity in muscle fibres termed 'plateau potentials' that make them temporarily inactive, says a study published today in eLife.

An understanding of these mechanisms and the ion channels involved may help the search for more effective therapies for weakness in Becker disease and other muscle diseases, and help understand how electrical activity is regulated in muscles.

Recessive myotonia congenita, also known as Becker disease, is a heritable skeletal muscle disease caused by mutated chloride channels in the muscles that do not work properly. People with the condition experience a phenomenon called myotonia whereby the muscles are hyperexcitable, meaning they are more sensitive than usual to activation. This results in stiff muscles that struggle to relax after being used.

After moving, patients can also suffer debilitating bouts of weakness that can last from seconds to minutes. "The mechanism underlying this weakness has remained a mystery since its initial description almost 50 years ago," explains first author Jessica Myers, a researcher at the Department of Neuroscience, Cell Biology and Physiology, Wright State University Boonshoft School of Medicine. "There are hints that weakness is due to hypoexcitability, or reduced sensitivity, of muscle fibres, but this conclusion is at odds with the discovery that muscle in Becker disease is hyperexcitable."

Myers and colleagues sought to uncover the mechanisms behind muscle weakness in patients by studying models of Becker disease in mice. They mimicked the disease by inactivating chloride channels either by genetically modifying them or by blocking them with a drug. They then measured how much force the muscles produced and the electrical activity within the muscle cells to see whether weakness was a result of hypo- or hyperexcitability.

The team found that the weakness was caused by temporary depolarisation of the muscle cells which they termed 'plateau potential'. At rest, muscle cells carry a negative electrical charge of -70 to -90 millivolts (mV) relative to their surroundings. When depolarised during a plateau potential, the charge reduces to a less negative state of between -30 and -45 mV which can last up to 100 seconds. Plateau potentials leave muscle fibres inexcitable, making them essentially inactive.

These results suggest that muscle affected by Becker disease rapidly cycles between hyper- and hypoexcitability as individual fibers switch from experiencing myotonia (causing stiffness) to the generation of plateau potentials (causing weakness), respectively. The state depends on the strength of the signal experienced by the muscle fibres: mild depolarisation triggers myotonia and more severe depolarisation triggers the generation of a plateau potential.

The team also demonstrated that both calcium and sodium ion channels are involved in creating a plateau potential, finding that sodium channels trigger this state while calcium channels are responsible for maintaining it. Moreover, blocking a subset of sodium channels with the drug ranolazine prevented the development of plateau potentials and eliminated the temporary muscle weakness.

"Further study is needed to identify all the ion channels involved in the generation of plateau potentials," concludes senior author Mark Rich, Professor at the Department of Neuroscience, Cell Biology and Physiology, Wright State University Boonshoft School of Medicine. "Doing so could lead to the development of novel therapies for weakness in Becker disease as well as similar diseases including periodic paralysis."

WASHINGTON, April 27, 2021 -- If a base station in a local area network tries to use a directional beam to transmit a signal to a user trying to connect to the network -- instead of using a wide area network broadcast, as base stations commonly do -- how does it know which direction to send the beam?

Researchers from Rice University and Brown University developed a link discovery method in 2020 using terahertz radiation, with high-frequency waves above 100 gigahertz. For this work, they deferred the question of what would happen if a wall or other reflector nearby creates a non-line-of-sight (NLOS) path from the base station to the receiver and focused on the simpler situation where the only existing path was along the line-of-sight (LOS).

In APL Photonics, from AIP Publishing, those same researchers address this question by considering two different generic types of transmitters and exploring how their characteristics can be used to determine whether an NLOS path contributes to the signal received by the receiver.

"One type of transmitter sends all frequencies more or less in the same direction," said Daniel Mittleman, co-author and an engineering professor at Brown, "while the other type sends different frequencies in different directions, exhibiting strong angular dispersion. The situation is quite different in these two different cases."

The researchers' work shows that the transmitter sending different frequencies in different directions has distinct advantages in its ability to detect the NLOS path and distinguish them from the LOS path.

"A well-designed receiver would be able to detect both frequencies and use their properties to recognize the two paths and tell them apart," Mittleman said.

Many recent reports within academic literature have focused on various challenges involved in using terahertz signals for wireless communications. Indeed, the term 6G has become a buzzword to encompass future generations of wireless systems that use these ultrahigh-frequency signals.

"For terahertz signals to be used for wireless communications, many challenges must be overcome, and one of the biggest is how to detect and exploit NLOS paths," said Mittleman.

This work is among the first to provide a quantitative consideration of how to detect and exploit NLOS paths, as well as a comparison of the behavior of different transmitters within this context.

"For most realistic indoor scenarios we can envision for an above-100 gigahertz wireless network, the issue of NLOS path is definitely going to require careful consideration," said Mittleman. "We need to know how to exploit these link opportunities to maintain connectivity."

If, for example, the LOS path is blocked by something, an NLOS path can be used to maintain the link between the base station and receiver.

"Interestingly, with a transmitter creating strong angular dispersion, sometimes an NLOS link can provide even faster connectivity than the LOS link," said Yasaman Ghasempour, co-author formerly at Rice University and currently an assistant professor at Princeton University. "But you can't take advantage of such opportunities if you don't know the NLOS path exists or how to find it."