Publisher Health

Does evolution explain why we can’t resist a salty chip? Researchers at NC State University found that differences between the elemental composition of foods and the elemental needs of animals can explain the development of pleasing tastes like salty, umami and sweet.
Taste tells us a lot about foods before they are swallowed and digested, and some tastes correspond with the elemental composition of foods. For example, an aged steak lights up the umami taste receptors, because it has a high concentration of the element nitrogen, which occurs in amino acid molecules. Nitrogen is essential for survival, but often occurs in low concentrations relative to the demand by animals. Likewise, sodium is limited in many foods in nature — think of life before supermarkets. So if you need sodium to survive — and all animals do — you are more likely to have adapted a taste for, and seek out, salty foods.
“Nutritional imbalances, even at the elemental level, can limit the growth and metabolism of animals,” says Lee Demi, a co-author of the study and postdoctoral researcher in NC State’s Department of Applied Ecology. “We posited that animals should have evolved the ability to taste, and enjoy, certain elements and nutrients that are most likely to be limiting for growth, due to their low concentrations in typical foods.”
To investigate this hypothesis, Demi and colleagues compared the body elemental composition of three animal groups (mammals, fish, and insects) to the elemental composition of plants, the base of most food webs. They predicted that animals who eat foods composed of particular elements that are rare or unpredictable are more likely to have taste receptors that reward them for finding those same elements.
“Because animals have very limited ability to change their elemental composition, the old adage that ‘You are what you eat’ doesn’t really apply,” says Demi. “Rather, animals are rewarded with pleasing tastes for ‘eating what they are’, at least from an elemental composition perspective, which helps reduce the prospect of dietary nutrient limitation.”
This is particularly important for omnivorous and herbivorous animals that eat a variety of different foods which vary in nutritional quality. Within this framework, taste becomes a tool that helps consumers prioritize which foods they should search for and consume, so they don’t waste time on foods that have less of these necessary elements. Equally, taste can also inform consumers to avoid foods that contain too much of an element they need. This is why eating a handful of chips is more attractive than eating a handful of table salt.
Where you are on the food chain can predict the complexity of your taste systems. Some top predators, like orcas, have lost many taste receptors over evolutionary time. This study suggests that predators are less likely to experience strong elemental imbalances in their diet than herbivores or omnivores. Because their prey already match their elemental needs, predators experience less selective pressure to maintain elaborate taste systems. However, these top predators have kept their taste for salt, which can be harmful if overconsumed.
“Affinity for certain foods must have strong evolutionary drivers, because without taste, animals would be forced to overconsume everything in the hopes of hitting the magic ratio of elements needed for growth and development,” says Benjamin Reading, co-author of the study and a professor in NC State’s Department of Applied Ecology. “They would need to eat way too much and end up excreting huge quantities of those things they need less of, which is not efficient.”
The research team also found strong evidence of convergent taste evolution in mammals, fish, and insects. Each group, although far apart on the phylogenetic tree, all have adapted tastes that prioritize the same infrequent elements, including sodium, nitrogen and phosphorus.
“Phosphorus is particularly intriguing because this recently discovered taste is most strongly linked to phosphate, which is also the primary form of phosphorus in many nucleic acids, ATP, phospholipids, etc.,” says Brad Taylor, a co-author of the study and professor in NC State’s Department of Applied Ecology. “Phosphate is the most readily available form of phosphorus for uptake by plants, and often the primary growth limiting element in organisms and ecosystems. So, links between the elemental form, taste receptors, organismal needs, and ecosystem are really direct.”
While the neurobiological process of taste has been extensively researched, this study is the first to explore taste as an evolutionary tool for optimal foraging. The researchers suggest that this may open a new area of thought on how taste can indicate how animals impact their environments through foraging, nutrient-cycling, and other core principles of ecology.
The work was supported by the U.S. National Science Foundation [grant number 1556914] as well as the Department of Applied Ecology and Dr. Jules Silverman at North Carolina State University.

Hypertension, or high blood pressure, kills more Americans than any other health condition. It is especially prevalent in Black Americans and is exacerbated by structural barriers to accessing high quality healthcare. In a 2018 randomized trial called the Los Angeles Barbershop Blood Pressure Study (LABBS), barbers were trained to screen their Black male patrons for hypertension and refer them to a pharmacist who visited the barbershop to counsel and treat individuals with high blood pressure. Participants in the barbershop-based, pharmacist-led program saw a 20-point drop in systolic (top number) blood pressure that they were able to sustain beyond the duration of the trial.
In a new paper published in the journal Circulation, researchers built a model to examine the potential impact of implementing similar blood pressure control programs at barbershops nationwide. The team found that such programs could reach one in three Black men with uncontrolled blood pressure nationally. Among men who participate, the program could avert 40 percent of major cardiovascular events like heart attacks or stroke.
The team also examined the economic constraints under which the program would have to be implemented in order to be considered cost-effective, and estimated that if barbershop-based programs could be delivered at a cost of roughly $1,500 per enrolled participant per year, it would be considered cost-effective by U.S. standards.
“Barbershop-based, pharmacist-led blood pressure control programs represent a novel and effective way to deliver hypertension care to Black men, who represent an underserved population that is disproportionately affected by the complications of uncontrolled hypertension,” said lead author Dhruv S. Kazi, MD, MS, Associate Director of the Richard A. and Susan F. Smith Center for Outcomes Research in Cardiology at Beth Israel Deaconess Medical Center (BIDMC). “Our findings provide a blueprint to guide nationwide implementation of a program that has the potential to save lives and improve health outcomes at a reasonable cost per participant.”
Kazi and colleagues projected clinical outcomes and direct healthcare costs of implementing barbershop-based, pharmacist-led blood pressure control programs, relative to usual care over 10 years. The team based these projections on the likely clinical outcomes for a hypothetical cohort of Black men ages 35-79 years living in U.S. metropolitan areas with a systolic (top number) blood pressure of 140 or above. Assuming the programs could reduce mean systolic blood pressure by 20 points, as was achieved in the LABBPS program, these community-based interventions would avert 8,600 major cardiovascular events annually relative to usual care, including 1,800 myocardial infarctions, or heart attacks, and 5,500 strokes. This is projected to lower healthcare costs by more than $200 million dollars a year.
Despite a range of pre-existing programs and incentives, blood pressure control in the U.S. has worsened in recent years. “There is no reason for us to accept the status quo — there are plenty of effective and affordable medications for blood pressure control if we can address the structural barriers to getting them to people,” said Kazi, who is also Associate Professor at Harvard Medical School. “The barbershop-based blood pressure control program, pioneered by the late Ronald G Victor, MD, challenges the dogma that high-quality blood pressure control can only happen in healthcare settings. By changing the locus of care to a trusted community setting and allowing trained pharmacists to prescribe antihypertensives and escalate doses of medications, Dr. Victor’s program achieved really impressive declines in blood pressure in an underserved population.”
Kazi concluded that to improve the health and lives of diverse communities, experts need to learn how to translate the findings of successful clinical trials into large-scale, cost-effective programs using tools from health economics and implementation science. “Our analysis advances that conversation by showing the way forward, clarifying how these programs can be scaled nationally and quantifying the enormous potential health benefits such a scale-up would bring.”
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Materials provided by Beth Israel Deaconess Medical Center. Original written by Terri Janos. Note: Content may be edited for style and length.

Jittery pet owners are asking vets, animal poison control centers and Twitter. Read on for answers.Of course you’re anxious.Your sweet, admittedly not overbright, four-legged pandemic pal is enamored with the horror movie of the season: relentless hordes of fat and sassy cicadas.Clattering and slow-moving, the 2021 Brood X swarmageddon taunts cats and dogs, who seem incapable of affecting diffidence. In recent weeks, many pets have obsessively been lunging and swatting. Then, gulping.Fearful owners are rushing to veterinarians and animal poison control centers, to say nothing of Dr. Google. Can cicada exoskeletons pierce intestinal linings? Is cicada fungus toxic to dogs?The answers are no and no.Christine Klippen, an emergency veterinarian at Friendship Hospital for Animals in Washington, a city currently held captive by cicadas, sounded a tad weary.“No, eating a cicada won’t make a dog or cat sick,” Dr. Klippen said.Large areas in 15 states, mostly from the Mid-Atlantic, stretching west to Ohio, are now thrumming with billions of Brood Xers, which have burst forth after a 17-year gestation, full of so much pent-up reproductive energy that last week they invaded a White House press corps charter plane, delaying a flight for hours. And in a pandemic year during which, according to a survey by the American Society for the Prevention of Cruelty to Animals, one in five American households adopted dogs and cats, rookie pet owners are primed to swallow cicada myths whole.After all, they have not had years of exposure to the God-awful things that pets routinely snarf down.More good news: If you haven’t seen or heard Brood X cicadas yet, you’re unlikely to. John Cooley, a cicada researcher and expert in ecology and evolutionary biology at the University of Connecticut, said that by now, they had all emerged and that by the Fourth of July, their newborns would have hatched and burrowed.“If it’s cold and miserable like it’s been in Maryland, that prolongs things,” Dr. Cooley, who maps sightings, said. “Sunny, hot weather burns them out.”An Invitation to the Cicada PartyThis spring, billions of cicadas will emerge from underground tunnels to sing, mate and die across the eastern United States. Here’s what to expect.To dogs and cats, cicadas look like “big flying treats,” as Dr. Klippen says. But, she adds, unless an animal has a rare allergy to chitin, the exoskeleton material, the bugs are not toxic. That includes a fungus that has been seen on these periodical cicadas, which can affect the bugs but not the snackers.“Most pets who ingest a few cicadas will only develop mild stomach upset,” said Tina Wismer, a veterinarian who is a senior director at the ASPCA Animal Poison Control Center in Urbana, Ill. Some cats and dogs have bellies so sensitive, she added, that they can even have a reaction to a new kibble. Most cicada-related calls to the poison center, she said, involve dogs vomiting up the exoskeletons.The wings are crunchy “but no more than dry dog food,” observed Ann Hohenhaus, a veterinary oncologist at the Animal Medical Center in New York.She and others dismissed the chatter about cicada shells slicing through intestinal walls. “Dogs will eat bones and feel sick but even shards don’t poke through the intestines,” she said. “But cicada shells are unknown to us, so we have decided we should worry about them.”Because dogs spend more time outdoors than cats, calls about feline cicada ingestion are rare. But cats do enjoy the occasional cicada amuse-bouche.“Outdoor cats don’t like static food,” Dr. Hohenaus said. “If something is alive and moving, they will go for it. People worry that because cats have small digestive tracts, the cicada will get stuck, but a cat can eat a whole mouse. It will digest the cicada just fine.”.css-1xzcza9{list-style-type:disc;padding-inline-start:1em;}.css-3btd0c{font-family:nyt-franklin,helvetica,arial,sans-serif;font-size:1rem;line-height:1.375rem;color:#333;margin-bottom:0.78125rem;}@media (min-width:740px){.css-3btd0c{font-size:1.0625rem;line-height:1.5rem;margin-bottom:0.9375rem;}}.css-3btd0c strong{font-weight:600;}.css-3btd0c em{font-style:italic;}.css-w739ur{margin:0 auto 5px;font-family:nyt-franklin,helvetica,arial,sans-serif;font-weight:700;font-size:1.125rem;line-height:1.3125rem;color:#121212;}#NYT_BELOW_MAIN_CONTENT_REGION .css-w739ur{font-family:nyt-cheltenham,georgia,’times new roman’,times,serif;font-weight:700;font-size:1.375rem;line-height:1.625rem;}@media (min-width:740px){#NYT_BELOW_MAIN_CONTENT_REGION .css-w739ur{font-size:1.6875rem;line-height:1.875rem;}}@media (min-width:740px){.css-w739ur{font-size:1.25rem;line-height:1.4375rem;}}.css-9s9ecg{margin-bottom:15px;}.css-1jiwgt1{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-box-pack:justify;-webkit-justify-content:space-between;-ms-flex-pack:justify;justify-content:space-between;margin-bottom:1.25rem;}.css-8o2i8v{display:-webkit-box;display:-webkit-flex;display:-ms-flexbox;display:flex;-webkit-flex-direction:column;-ms-flex-direction:column;flex-direction:column;-webkit-align-self:flex-end;-ms-flex-item-align:end;align-self:flex-end;}.css-8o2i8v p{margin-bottom:0;}.css-12vbvwq{background-color:white;border:1px solid #e2e2e2;width:calc(100% – 40px);max-width:600px;margin:1.5rem auto 1.9rem;padding:15px;box-sizing:border-box;}@media (min-width:740px){.css-12vbvwq{padding:20px;width:100%;}}.css-12vbvwq:focus{outline:1px solid #e2e2e2;}#NYT_BELOW_MAIN_CONTENT_REGION .css-12vbvwq{border:none;padding:10px 0 0;border-top:2px solid #121212;}.css-12vbvwq[data-truncated] .css-rdoyk0{-webkit-transform:rotate(0deg);-ms-transform:rotate(0deg);transform:rotate(0deg);}.css-12vbvwq[data-truncated] .css-eb027h{max-height:300px;overflow:hidden;-webkit-transition:none;transition:none;}.css-12vbvwq[data-truncated] .css-5gimkt:after{content:’See more’;}.css-12vbvwq[data-truncated] .css-6mllg9{opacity:1;}.css-1rh1sk1{margin:0 auto;overflow:hidden;}.css-1rh1sk1 strong{font-weight:700;}.css-1rh1sk1 em{font-style:italic;}.css-1rh1sk1 a{color:#326891;-webkit-text-decoration:underline;text-decoration:underline;text-underline-offset:1px;-webkit-text-decoration-thickness:1px;text-decoration-thickness:1px;-webkit-text-decoration-color:#ccd9e3;text-decoration-color:#ccd9e3;}.css-1rh1sk1 a:visited{color:#333;-webkit-text-decoration-color:#ccc;text-decoration-color:#ccc;}.css-1rh1sk1 a:hover{-webkit-text-decoration:none;text-decoration:none;}The operative word here is “few.” Consuming too much of anything, including cicadas, can lead to lethargy, diarrhea and vomiting, say veterinarians as well as basic common sense.“Dogs eat lots of stuff — they will paw open a pantry and eat five pounds of dog food before owners catch them,” Dr. Hohenhaus said. “One dog puked up a shark toy. So if you have a dog who goes to the country for the weekend and eats horse poop, he’ll have diarrhea on Monday morning.”As for those pets who have hoovered up cicadas and landed in the vet E.R., she said, cause and effect are not necessarily obvious. “I don’t know if the cicada shells made the dog sick or it was the Kleenexes and trash the dog ate out of the bathroom basket.”Cicadas can, however, incite some cats and especially dogs to binge. (Think potato chips: Can you eat just one?)“Because cicadas are so easy to catch, some animals are going to town eating them,” said Dr. Klippen, who sees perhaps a handful of dogs a week for this reason. The risks are not from the bugs, she said, but from dehydration related to vomiting and diarrhea, or from having absorbed pesticide sprayed on the cicadas.For dogs who can’t quit cicadas, “consider a basket muzzle,” Dr. Klippen said. “It’s beneficial and doesn’t prevent dogs from panting and drinking.”Also try walking your dog at dawn and dusk, Dr. Wismer advised, when cicadas are least active. Since cicadas are found in and around mature trees, avoid routes that include them.The heebie-jeebies over pets and cicadas springs mostly from the alignment of several factors. There’s the once-in-nearly-two-decades emergence of the bugs. And the heightened attachment and overprotectiveness that owners developed toward their pets in the past year during lockdown. Moreover, veterinarians said, people’s concerns are being revved by the internet and, er, the news media.“But basically, it’s something for us to talk about other than the coronavirus,” Dr. Klippen said.

Inspired by kirigami, the Japanese art of folding and cutting paper to create three-dimensional structures, MIT engineers and their collaborators have designed a new type of stent that could be used to deliver drugs to the gastrointestinal tract, respiratory tract, or other tubular organs in the body.
The stents are coated in a smooth layer of plastic etched with small “needles” that pop up when the tube is stretched, allowing the needles to penetrate tissue and deliver a payload of drug-containing microparticles. Those drugs are then released over an extended period of time after the stent is removed.
This kind of localized drug delivery could make it easier to treat inflammatory diseases affecting the GI tract such as inflammatory bowel disease or eosinophilic esophagitis, says Giovanni Traverso, an MIT assistant professor of mechanical engineering, a gastroenterologist at Brigham and Women’s Hospital, and the senior author of the study.
“This technology could be applied in essentially any tubular organ,” Traverso says. “Having the ability to deliver drugs locally, on an infrequent basis, really maximizes the likelihood of helping to resolve patients’ conditions and could be transformative in how we think about patient care by enabling local, prolonged drug delivery following a single treatment.”
Sahab Babaee, an MIT research scientist, is the lead author of the paper, which appears today in Nature Materials.
Stretchable stents
Inflammatory diseases of the GI tract, such as IBD, are often treated with drugs that dampen the body’s immune response. These drugs are usually injected, so they can have side effects elsewhere in the body. Traverso and his colleagues wanted to come up with a way to deliver such drugs directly to the affected tissues, reducing the likelihood of side effects.

A non-contact laser imaging system could help doctors diagnose and treat eye diseases that cause blindness much earlier than is now possible.
The new technology, developed by engineering researchers at the University of Waterloo, is designed to detect telltale signs of major blinding diseases in retinal blood and tissue that typically go unseen until it is too late.
With current testing methods, diseases such as age-related macular degeneration, diabetic retinopathy and glaucoma — which have no symptoms in their early stages — are usually diagnosed only after vision is irreversibly affected.
“We’re optimistic that our technology, by providing functional details of the eye such as oxygen saturation and oxygen metabolism, may be able to play a critical role in early diagnosis and management of these blinding diseases,” said Parsin Haji Reza, director of the PhotoMedicine Labs at Waterloo.
Patented technology at the core of the new system is known as photoacoustic remote sensing (PARS). It uses multicoloured lasers to almost instantly image human tissue without touching it.
When used for eyes, the non-invasive, non-contact approach dramatically improves both patient comfort and the accuracy of test results.
The technology is also being applied by Haji Reza and researchers in his lab to provide microscopic analyses of breast, gastroenterological, skin and other cancerous tissues, and to enable real-time imaging to guide surgeons during the removal of brain tumors.
“PARS may move us beyond the current gold standard in ophthalmological imaging,” said Dr. Richard Weinstein, an ophthalmologist and co-founder of the Ocular Health Centre. “For the first time, not just in ophthalmology but in the entire medical field, diagnosis and treatment of disease could be made prior to structural change and functional loss.”
Haji Reza, a professor of systems design engineering and co-founder of startup company illumiSonics, said researchers are working with several ophthalmologists and hope to start clinical trials within two years.
A paper on the research, Functional and structural ophthalmic imaging using noncontact multimodal photoacoustic remote sensing microscopy and optical coherence tomography, appears in the journal Scientific Reports.
The research team includes graduate students Zohreh Hosseinaee, Nicholas Pellegrino, Layla Khalili and Lyazzat Mukhangaliyeva, and research assistant Nima Abbassi.
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Materials provided by University of Waterloo. Note: Content may be edited for style and length.

Like amyloid plaque, the genetic variant APOE4 has long been associated with Alzheimer’s disease, but still little is known about the role the gene plays in the disease process.
Now, a new study published in Nature Aging not only sheds light on how the gene may instigate a cascade of pathologies that contribute to Alzheimer’s disease, but also suggests a new treatment target that might help people who carry the APOE4 gene in early and late stages of the disease. Keck School of Medicine of USC researchers found that APOE4 is associated with the activation of an inflammatory protein that causes a breakdown in the blood-brain barrier which protects the brain.
This research builds on a recent USC study that revealed APOE4 triggers leaks in the blood-brain barrier in humans, which lets toxic substances from the blood stream into the brain, damaging brain cells and disrupting cognitive functions. This process causes memory problems in patients whether or not their brain shows signs of amyloid-β, the sticky plaque peptide considered a hallmark of the disease.
The latest findings also suggest a new potential treatment to slow down or prevent the cognitive decline associated with Alzheimer’s disease in patients with the APOE4 gene, independently of amyloid-β pathology.
“We’re further focusing on therapeutics targets in blood vessels that could bring innovative treatments to people suffering from Alzheimer’s disease, both early and late stages of the disease. Current findings in mouse models might be particularly promising for treating late stage disease in the presence of advanced amyloid-β pathology,” said Berislav Zlokovic, MD, PhD, director of the Zilkha Neurogenetic Institute at the Keck School of Medicine of USC.
The role of APOE4, pericytes and Cyclophilin A in Alzheimer’s disease
APOE4 has been shown to accelerate the blood-brain barrier breakdown by damaging pericytes, a layer of cells that strengthen and protect the brain capillaries which make up the blood-brain barrier. This breakdown is also associated with higher levels of Cyclophilin A, a pro-inflammatory protein, in the brain vessels of Alzheimer’s disease patients with the APOE4 gene.
In this study, USC researchers focused on Cyclophilin A in mice with the APOE4 gene, which carries a high risk for Alzheimer’s disease, and mice with the APOE3 gene, which carries an average risk for Alzheimer’s disease. Cyclophilin A is found in pericytes and controls how strong the blood vessels are in maintaining the integrity of the blood-brain barrier. In the APOE4 mice, researchers found Cyclophilin A caused an enzyme that degrades blood vessels in the blood-brain barrier — matrix metalloproteinase 9 (MMP9) — to become active. This did not happen in the APOE3 gene mice.
Researchers then tried treating APOE4 mice with an inhibitor known to suppress Cyclophilin A. The inhibitor not only improved integrity in the blood-brain barrier in APOE4 mice, but also prevented development of further neuron loss and behavioral deficits. Researchers observed that the APOE4 mice treated with the inhibitor did not exhibit behavioral deficits during daily activities. This suggests that treatment targeting this pathway might have the potential to also slow down the progression of vascular and neurodegenerative disorders in people with Alzheimer’s disease who have the APOE4 gene.
“So far there has been little hope for those in the late stage of the disease, which is very hard on patients and their loved ones,” said Zlokovic. “We are excited to further study the potential that interventions focused on blood-brain barrier repair and blood vessel strength, independent of amyloid pathology, could have on slowing down or stopping neurodegeneration and cognitive decline in advanced Alzheimer’s disease.”
The inhibitor used in this study to suppress the Cyclophilin A, Debio-025, has been used in humans to treat hepatitis C, suggesting this could be a potential treatment for cognitive impairment in APOE4 carriers that show Cyclophilin A-MMP9 pathway activity in early or late disease stages.
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Materials provided by Keck School of Medicine of USC. Note: Content may be edited for style and length.

Alzheimer’s disease is the most common form of dementia and is characterized by neurodegeneration in regions of the brain involved in memory and learning. Amyloid beta and tau are two toxic proteins that build up in disease and cause eventual neuronal death, but little is known about how other cells in the brain react during disease progression.
A new study from the ASU-Banner Neurodegenerative Research Center (NDRC) and MIT/Koch Institute sheds new light on how disease processes manifest in patients with Alzheimer’s disease.
Diego Mastroeni of the NDRC teamed up Forest White and Douglas Lauffenburger, colleagues in MIT’s Department of Biological Engineering, to explore how protein and signaling pathways change in patients with Alzheimer’s disease. Their analysis captures a detailed molecular profile of changes in protein levels and alterations known as protein phosphorylation across a cohort of patients with well-preserved brain tissue, from the Banner Sun Health Research Institute. Their work creates a new model of disease progression, taking advantage of the heterogeneity that is inherent to human studies.
“This manuscript highlights the importance of integrating the phosphoproteome with the proteome and transcriptome datasets to get a better picture of the drivers of disease, from transcription to translation,” said Mastroeni. (The phosphoproteome refers to proteins that have undergone epigenetic modification through the addition of a phosphate group. The proteome incudes the full complement of all proteins in the body, while the transcriptome refers to the RNA messages produced by genes, which are subsequently translated into proteins.)
The researchers’ analysis highlights the links between toxic protein build-up, neurodegeneration, and the glial cells which support and protect neurons in the brain. In particular, they found an intriguing association between markers of neurodegeneration and two types of glial cell: oligodendrocytes and microglia. Progressive alterations in these cells may be key to understanding the causes of neurodegeneration.
The new study appears in the journal Nature Aging.
“Our results show that there are a plethora of cellular signaling pathways that are activated at all stages of disease. We may be able to repurpose available therapies to target protein kinases that regulate these cell signaling events,” White says. “Clinicians today are studying therapeutic effects on amyloid and tau as proxies for disease, but our results suggest that glia cells are involved at every step of the process. Improved understanding of glia cells and their roles in progressive neurodegeneration may provide new opportunities for treatment of this disease.”
“This collaborative effort is the kind of work that we at the NDRC value,” Mastroeni says. “No one individual can tackle this disease on their own; it’s going to take a group effort to combat this devastating illness.”
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Materials provided by Arizona State University. Original written by Richard Harth. Note: Content may be edited for style and length.

Researchers from the Graduate School of Engineering and the Center for Quantum Information and Quantum Biology at Osaka University unveiled a new solid state second-harmonic generation (SHG) device that converts infrared radiation into blue light. This work may lead to a practical daily-use deep ultraviolet light source for sterilization and disinfection.
Recently, deep ultraviolet (DUV) light sources have been attracting much attention in sterilization and disinfection. In order to realize a bactericidal effect while ensuring user safety, a wavelength range of 220-230 nm is desirable. But DUV light sources in this wavelength range that are both durable and highly efficient have not yet been developed. Although wavelength conversion devices are promising candidates, conventional ferroelectric wavelength conversion materials cannot be applied to DUV devices due to absorption edge.
Since nitride semiconductors such as gallium nitride and aluminum nitride have relatively high optical nonlinearity, they can be applied to wavelength conversion devices. Due to its transparency to 210 nm, aluminum nitride is particularly suitable for DUV wavelength conversion devices. However, realizing structures with periodically inverted polarity like conventional ferroelectric wavelength conversion devices has proven quite difficult.
The researchers proposed a novel monolithic microcavity wavelength conversion device without a polarity-inverted structure. A fundamental wave is enhanced significantly in the microcavity with two distributed Bragg reflectors (DBR), and counter-propagating second harmonic waves are efficiently emitted in phase from the one side. As the first step towards a practical DUV light source, a gallium nitride microcavity device was fabricated via microfabrication technology, including dry etching and anisotropic wet etching for vertical and smooth DBR sidewalls. By obtaining a blue SH wave, the effectiveness of the proposed concept was successfully demonstrated.
“Our device can be adapted to use a broader range of materials. They can be applied to deep ultraviolet light emission or even broadband photon pair generation,” senior author Masahiro Uemukai says. The researchers hope that because this approach does not rely on materials or periodically inverted structures, it will make future nonlinear optical devices easier to construct.
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Materials provided by Osaka University. Note: Content may be edited for style and length.

A team of scientists has shown that the healing of skin blisters is driven by hair follicle stem cells, which delay their own development in the process.
The healing process of the tissues in the human body is particularly well-studied in skin, especially as skin serves as a layer of protection from the environment. However, there remain some specific types of skin injuries where the healing process is not well understood.
A team of scientists from Japan and Italy, including Associate Professor Ken Natsuga from the Graduate School of Medicine at Hokkaido University, have used models of skin blisters to explore the effects of injury on developing skin tissue. Their discoveries were published in the journal EMBO Reports.
The scientists performed their tests on mice which had artificially generated epidermal detachment, or skin blisters. They investigated the healing process by monitoring gene expressions and cell proliferation, tracing cell lineages, and employing mathematical models.
The team found that a type of stem cells (SCs), hair follicle stem cells (HFSCs), play an outsize role in blister healing. The HFSCs are mainly responsible for the healing of subepidermal blisters, from the base of the wound. The wound-healing activity of HFSCs is accompanied by delayed growth of hair follicles in the regenerated skin tissue. When HFSCs are reduced, another group of SCs, the interfollicular epidermal stem cells (IFESCs), can also contribute to healing, but only from the blister margins. They also confirmed that blister healing was affected by the shapes of keratinocytes, the primary skin cells, although the mechanism by which the shapes affect healing is still unclear.
The findings have revealed the balance between wound healing and development in skin, indicating many possibilities for the treatment of skin blistering in humans. The models used in this study may themselves be used for the development of new therapies for blister healing. The role of sweat glands could not be investigated, as mice lack sweat glands, and the role of mesenchymal cells, which have previously been shown to be involved in healing of skin wounds, was not examined. Future work will focus on these aspects.
“Our findings of the healing processes pave the way for tailored therapeutic interventions for epidermolysis bullosa, pemphigoid diseases and other blistering diseases,” says Ken Natsuga.
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Materials provided by Hokkaido University. Note: Content may be edited for style and length.

Artemisone is a promising substance in the fight against malaria. However, the active ingredient has yet to be used due its instability and because it is not easily absorbed by the body. A team from Martin Luther University Halle-Wittenberg (MLU) and the Hebrew University of Jerusalem has now pushed this a bit further. They have developed a very simple method for preparing the active ingredient that makes it easier to administer and store. The researchers report on their work in the scientific journal Antimicrobial Agents and Chemotherapy.
Malaria is caused by single-celled parasites (plasmodia) and is one of the most widespread infectious diseases in the world. According to estimates by the World Health Organisation (WHO), there were around 229 million cases of the disease worldwide in 2019, and 409,000 people died. Africa is the most severely affected region.
Laboratory tests have already shown artemisone’s efficacy in combating the harmful parasites; however, it has not yet been put to use. “The substance is too unstable and cannot be easily absorbed by the body. Previous formulations have proven very costly to produce,” says Professor Karsten Mäder, head of the Pharmaceutical Technology Group at MLU. His research group specialises in the design and production of drug carrier systems. It aims to prepare active ingredients is such a way that optimises various properties, for instance efficacy, absorption in the human body, and stability of the substance. “We have developed a new formulation of artemisone in which the active ingredient is mixed with other substances. This is a very simple process that leads to a much more stable form. The process can be conducted in ordinary laboratories or factories,” says Mäder.
The new substance was tested against severe malaria on an animal model at the Hebrew University. It was well absorbed by the body and was able to successfully fight off the parasites. A smaller amount than previous formulations was needed, which comes with an advantage: a lower dose means fewer side effects can be expected.
In an earlier study, the team was also able to show that the new formulation of the drug is also very effective in treating schistosomiasis, a disease caused by flatworms. This disease is also widespread in the tropics.
Extensive clinical trials must be carried out before the active ingredient can be used as a medicine in humans. To this end, Mäder is in talks with several organisations that are committed to improving medical care in Africa.
The study was supported by the Deutsche Forschungsgemeinschaft (German Research Foundation, DFG).
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Materials provided by Martin-Luther-Universität Halle-Wittenberg. Note: Content may be edited for style and length.