Earth

A team of physicists has mapped how electron energies vary from region to region in a particular quantum state with unprecedented clarity. This understanding reveals an underlying mechanism by which electrons influence one another, termed quantum "hybridization," that had been invisible in previous experiments.

The findings, the work of scientists at New York University, the Lawrence Berkeley National Laboratory, Rutgers University, and MIT, are reported in the journal Nature Physics.

"This sort of relationship is essential to understanding a quantum electron system--and the foundation of all movement--but had often been studied from a theoretical standpoint and not thought of as observable through experiments," explains Andrew Wray, an assistant professor in NYU's Department of Physics and one of the paper's co-authors. "Remarkably, this work reveals a diversity of energetic environments inside the same material, allowing for comparisons that let us spot how electrons shift between states."

The scientists focused their work on bismuth selenide, or Bi2Se3, a material that has been under intense investigation for the last decade as the basis of advanced information and quantum computing technologies. Research in 2008 and 2009 identified bismuth selenide to host a rare "topological insulator" quantum state that changes the way electrons at its surface interact with and store information.

Studies since then have confirmed a number of theoretically inspired ideas about topological insulator surface electrons. However, because these particles are on a material's surface, they are exposed to environmental factors not present in the bulk of the material, causing them to manifest and move in different ways from region to region.

The resulting knowledge gap, together with similar challenges for other material classes, has motivated scientists to develop techniques for measuring electrons with micron- or nanometer- scale spatial resolution, allowing researchers to examine electron interaction without external interference.

The Nature Physics research is one of the first studies to use this new generation of experimental tools, termed "spectromicroscopy"--and the first spectromicroscopy investigation of Bi2Se3. This procedure can track how the motion of surface electrons differs from region to region within a material. Rather than focusing on average electron activity over a single large region on a sample surface, the scientists collected data from nearly 1,000 smaller regions.

By broadening the terrain through this approach, they could observe signatures of quantum hybridization in the relationships between moving electrons, such as a repulsion between electronic states that come close to one another in energy. Measurements from this method illuminated the variation of electronic quasiparticles across the material surface.

"Looking at how the electronic states vary in tandem with one another across the sample surface reveals conditional relationships between different kinds of electrons, and it's really a new way of studying a material," explains Erica Kotta, an NYU graduate student and first author on the paper. "The results provide new insight into the physics of topological insulators by providing the first direct measurement of quantum hybridization between electrons near the surface."

Flinders researchers have studied the giant cassowary’s eating, breathing and vocal structures and found a surprising missing link between two vastly different birds thought to be each other’s closest relative, the small flights South American tinamou, and the New Zealand moa.

The iconic and colourful Australian cassowary, the second largest living bird, has been studied for hundreds of years. However, their solitary nature in the dense rainforests of northern Queensland has ensured that many fundamental aspects of these animals continue to elude scientists.

Researchers from Flinders University in South Australia recognised that the throat structures involved with breathing, eating and vocalising (the syrinx, hyoid, and larynx) were almost totally unknown. Using advanced scanning technologies, the team at Flinders University were able to 3D image these structures, looking in detail at the anatomy and comparing them to that of other closely related birds.

“Scanning lets us see details that we wouldn’t be able to otherwise, including the shapes of internal structures, without causing damage to them” says lead author on the paper, Flinders PhD candidate Phoebe McInerney.

The results have been published in the international journal BMC Evolutionary Biology.

The cassowary’s closest relative is the Australian emu, so it was no surprise that they showed many similarities in the throat region.

“What did surprise us though was that despite extensive variation in this region between cassowaries and other primitive birds, known as palaeognaths, the extinct New Zealand moa and the living South American tinamou were very similar,” said McInerney.

Recent analysis of DNA has concluded that moa and tinamou are closest relatives. However, these results had been met with scepticism by some biologists: the moa was huge and flightless, and the tinamou is a small, flighted partridge-like bird.

And so, for many years, morphological similarities between the moa and tinamou eluded scientists, and yet, hidden deep within the throat, in a structure historically ignored, the answers have been uncovered: “The morphology of the often-neglected larynx has shown to be far superior than the other anatomical traits biologists previously used to infer evolutionary relationships for this group”, says Associate Professor Trevor Worthy, a co-author on the study.

“The unexpected family tree for primitive birds based on genomic evidence is looking more and more convincing”, says Professor Michael Lee, another co-author.

The researchers conclude that despite being historically overlooked, it is important not to forget the small things when studying evolutionary relationships among birds.

Just like we take a shower to wash away all the dirt and other particles, semiconductors also require a cleaning process. However, its cleaning goes extreme to make even trace contaminants "leave no trace". After all the chip fabrication materials are applied to a silicon wafer, a strict cleaning process is taken to remove residual particles. If this high-purity cleaning and particle-removal step goes wrong, its electrical connections in the chip are likely to suffer from it. With ever-miniaturized gadgets on the market, the purity standards of the electronics industry reach to a level, like finding a needle in a desert.

That explains why hydrogen peroxide (H2O2), a major electronic cleaning chemical, is one of the most valuable chemical feedstock that underpins the chip-making industry. Despite the ever-growing significance of H2O2, its industry has been left with an energy-intensive and multi-step method known as the anthraquinone process. This is an environmentally unfriendly process which involves the hydrogenation step using expensive palladium catalysts. Alternatively, H2O2 can be synthesized directly from H2 and O2 gas, although the reactivity is still very poor and it requires high pressure. Another eco-friendly method is to electrochemically reduce oxygen to H2O2 via 2-electron pathway. Recently, noble metal-based electrocatalysts (for example, Au-Pd, Pt-Hg, and Pd-Hg) have been demonstrated to show H2O2 productivity although such expensive investment has seen low returns that fails to meet the scalable industry needs.

Researchers at the Center for Nanoparticle Research (led by Director Taeghwan HYEON and Vice Director Yung-Eun SUNG) within the Institute for Basic Science (IBS) in collaboration with Professor Jong Suk YOO at University of Seoul recently report an ultimate electrocatalyst that addresses all of the issues that trouble H2O2 production. This new catalyst comprising the optimal Co-N4 molecules incorporated in nitrogen-doped graphene, Co1-NG(O), exhibits a record-high electrocatalytic reactivity, producing up to 8 times higher the amount of H2O2 that can be generated from rather expensive noble metal-based electrocatalysts (for example, Pt, Au-Pd, Pt-Hg and so on). The synthesized catalysts entirely comprise at least 2000 times less expensive elements (Co, N, C, and O) than the conventional palladium catalyst, and they are exceptionally stable without activity loss over 110 hours of H2O2 production.

Typically involving different phases of catalysts (usually solid) and reactants (gas), heterogeneous catalysts are widely exploited in many important industrial processes. Still, their catalytic property was thought to be controlled only by changing the constituent elements. In this study, the researchers verified that they can induce a specific interaction on heterogeneous catalysts by fine-tuning the local atomic configurations of the elements as seen in enzyme catalysts (Fig.2). Director Hyeon, the corresponding author of the study notes, "this study successfully demonstrated the possibility of controlling a catalytic property by tuning atomic compositions. This finding may bring us closer to discovering the fundamental properties of catalytic activities."

Based on the theoretical analysis, it was verified that the charge density of a cobalt atom on a nitrogen-doped graphene is highly dependent on the coordination structure surrounding the cobalt atom. Therefore, the researchers could control electron density of cobalt atoms by introducing either electron-rich or electron-poor species such as oxygen or hydrogen atoms. When electron-rich oxygen atoms are nearby, Co atoms become electron-deficient. On the other hand, when electron-rich hydrogen atom is nearby, the opposite trend was found (which would generate electron-rich Co atoms). Very interestingly, the electron density of Co atoms were critical for the electrochemical H2O2 production.

Next, the researchers designed the optimal cobalt atomic structure (Co1¬-N4(O)) by having all of the required conditions such as precise selection of element, synthesis temperature and various experimental conditions met. Combining theoretical simulations and nanomaterial synthesis technologies, the researchers were able to control the catalytic property in atomic precision. With electron-poor Co atoms (Co1¬-NG(O)), they were able to produce H2O2 with significantly high activity and stability, far surpassing the state-of-the-art noble metal catalysts. Conversely, electron-rich Co atoms exhibited a high reactivity for 4-electron oxygen reduction reaction to H2O formation which might be found useful for fuel cell applications.

Surprisingly, 341.2 kg of H2O2 can be produced within 1 day at room temperature and atmospheric pressure using 1 kg of Co1-NG(O) catalyst. This amount of H2O2 is up to 8 times higher the amount of H2O2 produced by the state-of-the-art noble metal catalysts (Fig.3). Co1-N4(O)) is an ultimate catalyst that allows low-cost, efficient, and eco-friendly production of H2O2. Professor Sung, the corresponding author says, "For the first time, we found that the catalytic property of heterogeneous catalysts can be fine-tuned in atomic precision. This unprecedented result will help us to understand previous unknown aspects of electrochemical H2O2 production. With this knowledge, we could design a scalable catalyst that is entirely composed of earth-abundant elements (Co, N, C, and O)."

Intense winds blowing from Africa through a mountainous gap on the western Red Sea coast have led to a buildup of summer dust over the Arabian Peninsula in the past decade. This increasing dust load could have long-term health and global climatic implications.

"The Arabian Peninsula is one of the prime climatic hotspots for dust activity," says KAUST Earth modeling specialist, Ibrahim Hoteit. Dust from the Middle East has significant effects on atmospheric heating, global atmospheric circulation patterns, regional oceanographic processes, and on the Indian summer monsoon system. Recent studies had noted increasing dust storm activity over the region, but little was known about its magnitude or long-term trends.

Hoteit and a team of scientists from KAUST and India have studied the long-term summer dust trends over the Arabian Peninsula since the beginning of the latest global climate shift in the early 1980s. They also investigated the mechanisms responsible for these trends.

They analyzed more than three decades of dust data--from 1980 to 2016--inferred from a combination of satellite observations, in addition to information on wind, surface air temperature, sea level pressure, surface soil temperatures and moisture related to the northeastern and eastern Arabian Peninsula and the southern Red Sea.

"We identified a strong summer dust loading over the Arabian Peninsula in the past decade," says former KAUST atmospheric scientist, Ravi Kumar Kunchala, who is now an assistant professor at the Indian Institute of Technology in Delhi. The increased dust loading, he explains, is largely due to increasingly strong westerly winds carrying Saharan Desert sands from Africa through the Tokar Gap between the mountains of the Red Sea's western coast.

The increasing summer dust load is also due to a significant rise in gusty winds over the Red Sea. Rising air and soil temperatures, together with reduced soil moisture, have also led to greater local dryness and an enhanced uplifting of dust.

"The results of our study provide information about the rate of dust increase," says Kunchala. "This information can be used in our models to investigate its impact on the regional climate."

The dust load could have important implications for water management, agriculture, health and transport, says Hoteit.

"Dust has an adverse effect on marine ecology, renewable energy, and it worsens air quality, which may cause acute respiratory diseases," he explains.

The team next plans to develop dust projections over the Arabian Peninsula, and to investigate how dust interacts with other climatic processes at the sub-seasonal and inter-annual scales.

WASHINGTON, Jan. 13, 2020 -- People have been developing different forms of shark repellent for decades -- the military even issued a chemical shark repellent called "Shark Chaser" to pilots, sailors and astronauts(!) from the end of World War II through the start of the Vietnam War. Thing is ... it didn't really work. Learn why they bothered passing it out or even created it in the first place: https://youtu.be/4u54c7cRAog.

Scientists have discovered that Acute Myeloid Leukemia (AML) grows by taking advantage of the B6 vitamin to accelerate cell division. The research team from Cold Spring Harbor Laboratory (CSHL) and Memorial Sloan Kettering Cancer Center (MSK) suggest they could halt the growth of this cancer by limiting its ability to manipulate the enzyme that pushes B6 to make proteins essential for cell division. It's an approach to attacking cancer without harming healthy cells, which need the B6 vitamin to survive.

Currently, only one-third of AML patients will survive five years after diagnosis. That's because, like many other deadly cancers, the cells involved in this aggressive form of blood cancer can divide and spread faster than most treatments can kill them.

CSHL Fellow Lingbo Zhang wanted to know how AML can achieve such rapid growth, so he looked closely at the genes of the disease's cancerous white blood cells.

"We found more than 230 genes that are very active in leukemic cells and then we tested them, one by one," he explained.

Using CRISPR gene-editing technology, Zhang's lab shut down the activity of each of these 230 suspect genes to see if their absence would stop the cancer cells from proliferating. Among the hundreds of genes they tested, one pattern emerged. The gene which produces PDXK, the enzyme that helps cells use vitamin B6, proved most important for the growth of the cancer.

Scott Lowe, a former CSHL fellow and currently the chair of the Cancer Biology and Genetics program at MSK, said "while the action of certain vitamins has previously been linked to cancer, the specific links between vitamin B6 identified here were unexpected."

The B6 vitamin is crucial to cell metabolism, producing energy and other resources important for cell growth. In a healthy cell, the PDXK enzyme manages the activity of B6, making sure that the vitamin does the job when needed. Because normal cells don't actually divide all the time, the PDXK enzyme isn't always pushing the B6 vitamin to be active.

It's a different dynamic in cancer cells, which divide more frequently than normal cells. In AML cells, Zhang saw that the PDXK enzyme was always pushing B6 activity.

What this shows is that, "leukemic cells are addicted to vitamin B6," he said. "You can call it a vulnerability of the cancer."

Zhang cautions that his research on how cancer cells use the B6 vitamin to proliferate does not mean that cancer patients would necessarily benefit from reduced intake of B6 vitamin as part of their diet. The B6 vitamin is necessary for the survival of healthy cells. Zhang's research shows that cancer cells take advantage of the PDXK enzyme to increase B6 vitamin activity. This increased activity fuels AML growth.

Zhang and his colleagues say the next step is to develop a drug that specifically blocks leukemia from activating the PDXK enzyme. By manipulating the way the enzyme manages the activity of B6, a drug could slow or even stop the growth of cancerous cells without the profound side effects that would result from completely eliminating B6 from healthy cells. With the help of medicinal chemists, the team is now exploring this route.

Video: https://www.youtube.com/watch?v=Jm1FovsaK48

London, UK: A neuroimaging study recently published in the journal Cephalalgia, the official journal of the International Headache Society, shared more evidence of structural changes in the brain of migraine patients. The study, entitled "Structural connectivity alterations in chronic and episodic migraine: A diffusion magnetic resonance imaging connectomics study", was conducted by a multidisciplinary team of neurologists and bioengineers, coordinated by Dr. Ángel Luis Guerrero, from the Headache Unit, Department of Neurology, University of Valladolid, Spain.

Migraine is one of the most disabling diseases in the world. To date, it is only diagnosed based on self-reported clinical symptoms, with no overt biomarker identified yet. As a neurological disorder, migraine is known to result from an aberrant central nervous system functioning. On the other hand, it may itself impact brain functioning with increased frequency of headache attacks (e.g., in chronic migraine patients).

Different research groups all around the world are attempting to uncover a brain signature of migraine patients, and nowadays brain connectivity is in the spotlight. Brain connectivity is obtained by neuroimaging techniques capable of mapping a full set of patterns of anatomical links in the brain and the strengths of these links (connectomes). The interpretation of these interactions follows the functional characteristics of each brain structure linked.

Dr. Guerrero's team assessed brain images from 160 volunteers; fifty healthy participants, 54 episodic migraine patients, and 56 chronic migraine patients. Migraine patients were assessed in the interictal period (headache-free days). Using a whole-brain tractography approach from diffusion magnetic resonance imaging (dMRI) and diffusion tensor imaging (DTI) techniques, a total of 620 connections between 84 cortical and subcortical gray matter regions were analyzed.

The researchers found structural brain connectivity changes between migraine patients and healthy volunteers, as well as between episodic and chronic migraine patients. Based on the number of streamlines from the anatomically-constrained tractography analysis and DTI descriptors, they found the following main patterns of structural changes:

Migraine Patients vs Controls

Simultaneous higher and lower number of streamlines in migraine patients, suggesting respectively coexistent strengthening and weakening structural connectivity changes in migraine. Strengthening connectivity was observed in many areas deeply implicated in migraine's pathophysiology, such as the caudate nucleus, thalamus and hippocampus, and other regions such as the insula, the superior frontal gyrus, and the precentral gyrus. The authors contextualized the role of the thalamus in the symptomatology of migraine such as photophobia, allodynia, and central sensitization processes, and the role of insula as the "hub of activity" in migraine. Strengthening connectivity in the hippocampus is akin to its role in pain processing and pain-related attention and anxiety.

For weakening connectivity patterns, the authors underscore the changes in the temporal lobe of migraine patients, which may represent a feature of interictal malfunctioning with other pain processing areas in these patients.

Episodic vs Chronic Migraine

Compared to episodic migraine patients, chronic migraine showed more streamlines, but decreased DTI descriptors (in axial and radial diffusivity), suggesting two different mechanisms connectivity alteration; more streamlines meaning potential adaptation to painful stimuli, and reduced diffusivity meaning possible axonal disturbance.

Moreover, in chronic migraine patients, DTI descriptors were positively correlated with the time from migraine onset, suggesting white matter plastic adaptation to highly recurrent painful stimuli. When adding the history of chronic migraine (the duration of chronic migraine) as a covariate in the statistical analyses, they found reduced streamlines of connections with the insula and thalamus, which was interpreted as indicative of temporal changes in pain processing areas throughout the course of migraine, resulting in plastic maladaptive changes.

According to Álvaro Planchuelo-Gómez, a bioengineer and the first author of the study, "This kind of study is very important to further investigate other aspects of the disease, such as identifying patterns of changes in patients who revert from the chronic to the episodic form of the disease, and treatment effects". Finally, another relevant aspect of this research is underscored by Dr. David García-Azorín, a neurologist and co-author of the study, "Migraine has no biomarker yet, therefore, more studies engaging the effort of a multidisciplinary team are needed to better understand the complexity of this disease, and, hopefully, establish a brain signature of migraine patients".

DES PLAINES, IL-- The results of a study conducted by researchers from Indiana University School of Medicine may not support troponin testing for acute coronary syndrome (ACS) in selected elderly patients with nonspecific complaints (NCSs). The study findings will be published in the January 2020 issue of Academic Emergency Medicine (AEM), a journal of the Society for Academic Emergency Medicine (SAEM).

The lead author of the retrospective observational multicenter cohort study is Alfred Z. Wang, MD, assistant professor of clinical emergency medicine, Indiana University School of Medicine.

Wang et al. found that while consideration for ACS is prudent in selected elderly patients with NSCs, ACS was rare. In the series of elderly patients presenting to the ED with nonspecific complaints, most patients underwent troponin testing, and although 20 percent of those tested had an elevated troponin, the diagnostic yield for ACS was low. Only 1.2 percent of patients (6.0 percent of those with elevated troponin) were determined to have ACS. Further, only one patient underwent angiography, and no patients received reperfusion therapy; nonetheless, emergency physicians admitted everyone with an elevated troponin. Give the false?positive rate in the study, the authors suggest that the study results may not support routine troponin testing for ACS in geriatric patients.

While previous work has found that elderly patients, especially those patients older than 75, with ACS can present with nonspecific complaints, this is the first study to define the rate of ACS and evaluate the utility of troponin testing in elderly patients with nonspecific complaints. The study provides an estimate of the rate of ACS given nonspecific complaints, providing a previously unknown baseline risk estimate or pretest probability in this population.

Commenting on the study is W. Frank Peacock, MD, professor and vice chair for research, Henry JN Taub Department of Emergency Medicine, Baylor College of Medicine, Houston, Texas, and president of Comprehensive Research Associates:

"This study calls into question the routine practice of troponin testing in every single elderly patient with non-specific but potentially concerning symptoms. They report a false positive ACS rate exceeding 90 percent, which makes it hard to think that troponin testing was useful in most of their patients. But pointedly, some of their patient's died and the lack of a helpful troponin doesn't mean they shouldn't be admitted."

A new study identifies the non-native species most likely to invade the Antarctic Peninsula region over the next decade. It provides a baseline for all operators in the region to look at mitigation measures. The study is published in the journal Global Change Biology (13th January 2020).

Fragile polar biological communities in marine and terrestrial Antarctic habitats are vulnerable to invasion by species from other parts of the world. In some cases they can have devastating effects. Lead author Dr Kevin Hughes, an environmental researcher at British Antarctic Survey (BAS), worked with an international team of researchers to identify which non-native species are most likely to threaten biodiversity and ecosystems in the Antarctic Peninsula region.

The team studied hundreds of academic papers, reports and databases, to find species most likely to invade the Antarctic Peninsula region. Of the 103 species considered in detail, 13 were identified as most likely to invade.

Dr Hughes says: "The Antarctica Peninsula region is by far the busiest and most visited part of Antarctica due to growing tourism and scientific research activities. Non-native species can be transported to Antarctica by many different means. Visitors can carry seeds and non-sterile soil attached to their clothing and footwear. Imported cargo, vehicles and fresh food supplies can hide species, including insects, plants and even rats and mice. Marine species present a particular problem as they can be transported to Antarctica attached to ship hulls. They can be very difficult to remove once established."

BAS marine biologist and co-author Dr David Barnes says:

"Marine invertebrates such as mussels and crabs are top of the list of species considered most likely to invade the Antarctic Peninsula region, but flowering plants such as button weeds (e.g. Leptinella scariosa) and mites and springtails were also identified. We know mussels can survive in polar waters, and can spread easily. When they establish they can dominate life by smothering the native marine animals that live on the seabed."

Some of the sub-Antarctic islands such as Marion Island and South Georgia have already been invaded by rats, mice or other vertebrates. However, this is not expected to happen on the Antarctic Peninsula anytime soon.

Professor Helen Roy, an ecologist at the UK Centre for Ecology & Hydrology who oversaw the study, says:

"We think the conditions in the Antarctic Peninsula region will remain too extreme to allow rodents to colonise outside. However, rats and mice could survive by hiding within research station buildings, so everyone needs to remain vigilant for droppings and gnaw marks".

Some non-native species have already established themselves near research stations and visitor sites. Eradication of invasive species is possible but has proven difficult and costly. Professor Roy continues:

"It is critical to ensure that comprehensive biosecurity checks are implemented by all visitors coming to the area to prevent invasive non-native species getting to Antarctica in the first place. Only then will we be able to reduce the risks and protect these amazing, but vulnerable Antarctic communities from the threat of invasive non-native species."

This study was funded by the UK Government through the GB Non-Native Species Secretariat and Natural Environment Research Council (NERC-UKRI), and includes scientists from Argentina, Austria, Belgium, Cyprus, Ireland, Italy, Spain, the United Kingdom (including its Overseas Territories of the British Antarctic Territory, Falkland Islands, South Georgia & the South Sandwich Islands and Tristan da Cunha) and the United States.

New research indicates that there is a higher risk of early death among patients with oropharynx cancer when not caused by human papillomavirus (HPV), than those whose tumors are HPV-positive. The findings are published early online in CANCER, a peer-reviewed journal of the American Cancer Society.

The incidence of oropharynx cancer--a type of throat cancer that occurs in the tonsils and base of the tongue--is increasing in the United States, with rates that are more than twice as high in men than in women. Recent evidence has shown that approximately 75 percent of these cancers are due to infection with HPV, a sexually transmitted virus that can mostly be prevented through vaccination.

A team led by Danielle N. Margalit, MD, MPH, of the Dana-Farber/Brigham & Women's Cancer Center and Harvard Medical School in Boston, designed a study to better understand the causes and risks of early death among patients with oropharynx cancer and to determine how these risks differ in patients with and without HPV-related tumors.

The researchers' analysis included information on 4,930 U.S. patients who were diagnosed with nonmetastatic oropharynx cancer from 2013 to 2014, including 3,560 whose cancers were HPV-positive and 1,370 whose cancers were HPV-negative. Patients were followed for a median of 11 months.

Compared with patients whose cancers were HPV-negative, those whose cancers were HPV-positive had a lower risk of dying from any cause within two years (10.4 percent versus 33.3 percent) and a lower risk of dying from head and neck cancer (4.8 percent versus 16.2 percent). Patients who had HPV-positive oropharynx cancer also had a lower risk of dying from cancers other than head and neck cancer.

"The study is really eye-opening when it comes to the high risk of death among patients with HPV-negative oropharynx cancer," said Dr. Margalit. "The information can be put to use by clinicians who see patients after treatment. They need to be vigilant not just about head and neck cancer recurrence, but also about screening for other cancers and non-cancer comorbidities that can influence patients' risk of early death, and they should counsel patients on addressing modifiable risk factors."

An Italian research team has refined the history and origins of two extremely common pathogens in human populations, herpes simplex virus type 1 and type 2.

As many of us may experience, literally on the skin, the common herpes simplex virus type 1 is a primary cause of orofacial lesions. The less prevalent form, herpes simplex virus type 2, is usually responsible for genital herpes. Both viruses can also cause very serious diseases, including non-epidemic encephalitis and neonatal herpes infection. In the latter case, the virus is generally transmitted by the mother during delivery and the consequences can be extremely serious for the infant.

To better understand the origins of the virus, the research team has shown that the evolutionary history of these two viruses is different and more complex than previously thought.

"We analyzed the diversity of the two viruses in relation to their geographical origin," researcher Diego Forni explains, "and what we noticed are that viruses deriving from distinct continents were not particularly different, an observation that is not consistent with the hypothesis of an ancient migration. Our data, however, clearly indicated that the two viruses originated in Africa. We therefore thought it was necessary to estimate when the viral strains circulating today among human populations left the African continent. "

The study, conducted at the IRCCS Medea in collaboration with the University of Milan, has just been published in the advanced online edition of Molecular Biology and Evolution.

Just as for other viruses belonging to the Herpesviridae family (e.g., viruses that cause chickenpox and mononucleosis), herpes simplex viruses type 1 and 2 are very similar to viruses that infect African great apes. In many cases these viruses have evolved together with their hosts and have infected our species since it originated in Africa. To date, Africa remains the continent where herpes simplex viruses type 1 and 2 are most prevalent. This gave rise to the hypothesis that the viral strains that infect us today left Africa in very ancient times. It was thought this coincided during the major "Out of Africa" migratory event that, around 60,000 years ago, led humans to populate all other continents.

"Recently, thanks to the study of viruses found in archaeological remains, the scientific community has a better knowledge of the speed at which viral species evolve," said study co-author Manuela Sironi. "Thus, we can use rather precise methods that allow the dating of viral origin and dispersal. By applying these methods, we estimated that the circulating strains of herpes simplex virus type 1 migrated from Africa about 5000 years ago. The exit from Africa of herpes simplex virus type 2 was even more recent and probably occurred in the eighteenth century."

The type 2 herpes result draws a link between epidemiological data and a major historical event --- the height of the transatlantic slave trade. In this century, millions of people were deported from Africa to the Americas. Most likely, this heinous forced human migration also led to the initial spread of herpes simplex virus type 2 in the Americas. In fact, the prevalence of the virus is higher in this continent than elsewhere and it is second only to Africa.

And herpes simplex virus type 2 is probably not the only pathogen to have been introduced to the American continent as a result of the slave trade. Previous studies have shown that the same happened for yellow fever virus and for a parasitic worm (Schsitosoma mansoni). For ecological reasons these pathogens remained confined to tropical or subtropical areas. Herpes simplex virus type 2, instead, found no barriers to today's planetary spread.

Online health videos can be an important source of cancer education, according to Rutgers researchers. Their review, published in the Journal of Cancer Education, analyzed existing research to see how people obtained their cancer knowledge and how educational videos they watched prompted a change in their behavior.

"This review demonstrates the benefit of using digital videos for cancer health education ranging from cancer prevention to treatment," said Nicholas Acuna, the paper's lead author and a recent graduate student at Rutgers School of Public Health.

Examining literature from three large health databases from PubMed, MEDLINE and PsychINFO, the researchers focused on people's cancer knowledge, their preferred method of receiving information and any changes made in behavior. They found that people who viewed online digital videos had an increase in awareness and understanding of cancer risk factors and screening procedures. They also found that YouTube was the preferred social media platform for watching these videos, over Twitter and Facebook. In addition, they noted that there was an increase in behavioral changes such as self-skin inspections and the likelihood of people seeking lung cancer screening increased after viewing online digital videos.

This review noted that while many studies examining digital video use for cancer health education demonstrated an increase in a person's cancer knowledge, potential behavioral changes and preference to digital videos, there was a lack of studies that focused on diverse populations, despite the fact that participants in several of the studies identified mostly as non-Hispanic/Caucasian.

"By increasing access to cancer information using online platforms, we have the opportunity to reduce barriers related to health literacy and improve health in underserved populations," said senior study author Pamela Valera, an assistant professor at Rutgers School of Public Health and an associate member of the Cancer Prevention and Control Program at Rutgers Cancer Institute of New Jersey.

According to Valera, 87 percent of adults who access health information online use their cell phones, where social media use is also the highest. "While digital health videos addressing cancer can lead to improved health and well-being, the direction we should begin to go is to reach the needs of disadvantaged populations," she said. "Videos are an inexpensive way to deliver a clear, consistent message, and they allow viewers to proceed or re-watch at their own pace, which make them especially effective for people with low health literacy."

Valera stressed the importance of people researching the source of video education to make sure the information is coming from a reliable source.

New research from UC Riverside identifies a protein that controls plant growth -- good news for an era in which crops can get crushed by climate change.

Researchers found the protein, IRK, while looking for clues to the ways plant cells divide or expand. They discovered IRK in the roots cells of a plant related to mustard.

"When this protein is present, the root perceives a signal that tells cells not to divide," said Jaimie Van Norman, who led the study and is an assistant professor of plant sciences at UCR. "If we can get the plant to ignore those signals, we may be able to get it to grow in conditions where it might not otherwise."

The team's work on IRK was recently published in Developmental Cell. The research demonstrates that turning off the gene producing IRK causes an increase in the number of times the plant's root cells divide. Additional cells can lead to bigger roots, and perhaps to plants that are better at taking up nutrients from the soil and grow larger.

There may be some instances in which farmers also want to limit plant growth. For example, keeping weeds small, or trying to pause crop growth until a severe storm passes. IRK can be instrumental for both goals.

"This discovery gives us another way to control growth," Van Norman said. "Understanding how the plant itself stops growth can also allow us to accelerate growth."

So far, Van Norman's team has only tested the effects of turning off the IRK gene in Arabidopsis, the mustard relative. However, Van Norman said the IRK protein is also found in other crop plants.

This research is notable not only for its potential impact on crop and food security, but also because roots have historically been less well studied than the above-ground parts of plants. This is likely due to the relatively inaccessible nature of roots, Van Norman said.

However, the roots are critical for plant survival and for the production of above-ground plant organs such as leaves flowers and fruits. Therefore, understanding their function and development is critical in efforts to improve crop productivity.

Previous research has examined the role of signals sent between cells up and down the plant from the roots up toward the shoots and vice versa. This study shows communication between cells across the root is important as well.

"There was a longstanding hypothesis that this type of horizontal communication between cells was important, and this work provides new evidence that it is," Van Norman said.

Next, Van Norman is hoping to understand whether bigger roots survive stress better. Some of the biggest challenges to crops include drought and high levels of salinity in soils.

Salts accumulate in soil both from natural and manmade sources, such as fertilizers and salts in irrigation waters. If there is too much salt built up near the soil surface, it can prevent vital processes in plant growth and even cause crops to fail entirely.

Out of an abundance of caution and without accurate salinity measurements, farmers have traditionally over-irrigated their fields to send salts into lower soil depths where they are less harmful to crops. However, this practice is being scrutinized as both the quantity and quality of water becomes scarcer.

"It may be the case that by understanding what happens when the IRK-producing gene is turned off, we can make root growth less sensitive to soil conditions that pose a threat to food security," Van Norman said.

In experiments with genetically engineered and old mice, Johns Hopkins Medicine researchers say they have added to evidence that the vast majority of low back pain in people may be rooted in an overgrowth of pain-sensing nerves into spinal cartilaginous tissue.

An estimated 80% of people worldwide will experience low back pain in their lifetimes, sometimes owing to strain or injury. But the vast majority of low back pain, the researchers say, emerges in the absence of injury, especially in older age.

The new experiments were designed to investigate whether a painful overgrowth of sensory nerves into the cartilaginous endplates in the spine could be the root of these unexplained cases.

The findings, published Dec. 10 in Nature Communications, may eventually help develop new treatments that target abnormal nerve growth in the spine.

The spine can be characterized as a series of joints, each made up of a bony vertebrae, a spinal disc and a layer of soft tissue called cartilage endplates that cushion the vertebral bones to protect them from the weight of the body.

"The cartilage endplate is the cushion on a seat that makes it more comfortable. But, like similar tissue in knee and hip joints, it succumbs to wear and tear over time," says Xu Cao, Ph.D., Lee Riley Professor of Orthopaedic Surgery and researcher in the Johns Hopkins Institute for Cell Engineering at the Johns Hopkins University School of Medicine.

Cao says he and his team have long suspected that age-related changes in the tissues that make up the spinal column provide fertile ground for abnormal nerve growth, making the normal load-bearing work of the spine painful.

To study this idea, Cao and his team analyzed samples of the bony end plates of vertebrae from mice aged more than 20 months, the human equivalent of about 70-80 years old. The researchers found that the soft, cartilaginous tissue in the mice's spines became hardened and resembled diffuse bone with a Swiss cheese-like structure.

In previous studies, Cao's team reported that an aging or instable spine induces the cartilage endplates to change into porous bony structures that provide spaces for nerves to penetrate the dense structure of the bone. A specialized cell type, called osteoclasts, creates the porous bone structure where the cartilage should be. Cao thought that perhaps the signaling molecule netrin-1 secreted by osteoclasts during this process invited abnormal nerve growth and the resulting back pain.

"Cartilage does not typically have nerve and blood vessels. However, when cartilage becomes a porous bony structure with growth of nerve fibers, it could be the source of back pain," says Cao.

To test this idea further, Cao and his colleagues first analyzed tissue samples from the spines of old mice under the microscope, labeling the hole-building osteoclasts and nerve fibers with fluorescent tags. They found that osteoclasts and nerve fibers were present in the same areas of vertebrae, suggesting that the osteoclasts could be signaling the nerve growth in some way, perhaps with netrin-1.

Next, the team designed an experiment to prevent the osteoclasts from producing the abnormal 'Swiss-cheese' bone growth and secreting netrin-1 to see if nerve growth in the cartilaginous tissue -- and the accompanying pain -- could be stopped.

They genetically engineered mice to lack the gene that codes for osteoclast formation, and performed a surgery on the mice to destabilize the joints between their vertebrae -- mimicking similar instability seen in people with low back pain. The researchers found that the mice lacking osteoclast cells had fewer pain-sensing nerves in the endplates of their vertebrae than mice with the gene.

Cao says those results show that the porous structure of cartilaginous endplates is an important lead in understanding how unexplained low back pain develops. His team next plans to conduct laboratory experiments using compounds that slow the abnormal bone growth to test their potential to treat low back pain.

The technology is available for licensing through Johns Hopkins Technology Ventures, which also is pursuing patent protection.

Five years after having an abortion, over 95 percent of the women in a landmark UC San Francisco study said it was the right decision for them.

The findings, published Sunday, Jan. 12, 2020, in Social Science & Medicine, come as many states are requiring waiting periods and counseling for women seeking abortions, based on the assumption that they may regret having them.

But the researchers at UCSF's Advancing New Standards in Reproductive Health (ANSIRH) found no evidence that women began to regret their decisions as years passed. On the contrary, the women reported that both their positive and negative feelings about the abortion diminished over time. At five years, the overwhelming majority (84 percent) had either positive feelings, or none at all.

"Even if they had difficulty making the decision initially, or if they felt their community would not approve, our research shows that the overwhelming majority of women who obtain abortions continue to believe it was the right decision," said Corinne Rocca, PhD, MPH, associate professor in the UCSF Department of Obstetrics, Gynecology and Reproductive Sciences, and first author of the study. "This debunks the idea that most women suffer emotionally from having an abortion."

The researchers analyzed data from the Turnaway Study, a five-year effort to understand the health and socioeconomic consequences for nearly 1,000 women who sought abortions in 21 states around the country. The analysis included 667 participants who had abortions at the start of the study. The women were surveyed a week after they sought care and every six months thereafter, for a total of 11 times.

While women did not report regretting their decision, many did struggle initially to make it. Just over half said the decision to terminate their pregnancy was very difficult (27 percent) or somewhat difficult (27 percent), while the rest (46 percent) said it was not difficult. About 70 percent also reported feeling they would be stigmatized by their communities if people knew they had sought an abortion, with 29 percent reporting low levels and 31 percent reporting high levels of community stigma.

Those who struggled with their decisions or felt stigmatized were more likely to experience sadness, guilt and anger shortly after obtaining the abortion. Over time, however, the number of women reporting these negative emotions declined dramatically, particularly in the first year after their abortion. This was also true for those who initially struggled with their decision.

And relief was the most prominent emotion reported by all groups at the end of the study -- just as it was at every time point in the study.

"This research goes further than previous studies, in that it follows women for longer, and was conducted on a larger sample from many different clinics throughout the U.S.," said Julia Steinberg, PhD, an assistant professor in the department of family science at the University of Maryland, College Park, who wrote an accompanying commentary on the study in Social Science & Medicine. "It shows that women remain certain in their decision to get an abortion over time. These results clearly disprove claims that regret is likely after abortion.