Researchers solve mystery surrounding dielectric properties of unique metal oxide

University of Minnesota Associate Professor Bharat Jalan and his students discovered that the true dielectric constant of their strontium titanate films exceeds 25,000—the highest ever measured for this material.
Credit: Jalan Group, University of Minnesota

A University of Minnesota Twin Cities-led research team has solved a longstanding mystery surrounding strontium titanate, an unusual metal oxide that can be an insulator, a semiconductor, or a metal. The research provides insight for future applications of this material to electronic devices and data storage.

The paper is published in the prestigious Proceedings of the National Academy of Sciences of the United States of America (PNAS), a peer-reviewed, multidisciplinary, scientific journal.

When an insulator like strontium titanateis placed between oppositely charged metal plates, the electric field between the plates causes the negatively charged electrons and the positive nuclei to line up in the direction of the field. This orderly lining up of electrons and nuclei is resisted by thermal vibrations, and the degree of order is measured by a fundamental quantity called the dielectric constant. At low temperature, where the thermal vibrations are weak, the dielectric constant is larger.

In semiconductors, the dielectric constant plays an important role by providing effective “screening,” or protection, of the conducting electrons from other charged defects in the material. For applications in electronic devices, it is critical to have a large dielectric constant.

A Fresh Take on Fat: Nanoparticle Technology Provides Healthy Trans, Saturated Fat Alternative

Yangchao Luo, an associate professor in the College of Agriculture, Health and Natural Resources.
 Credit: Jason Shelton/UConn Photo

The old adage that oil and water don’t mix isn’t entirely accurate. While it’s true that the two compounds don’t naturally combine, turning them into one final product can be done. You just need an emulsifier, an ingredient commonly used in the food industry.

Yangchao Luo, an associate professor in the College of Agriculture, Health and Natural Resources, is using an innovative emulsification process for the development of a healthier shelf-stable fat for food manufacturing.

Luo is working with something known as high internal phase Pickering emulsions (HIPEs). High internal phase means the mixture is at least 75% oil. Pickering emulsions are those that are stabilized by solid particles.

Previous research in Pickering emulsions has focused on non-edible particles, but Luo is interested in bringing HIPEs to the food industry as an alternative to trans and saturated fats.

This new approach could have a major impact on how food is produced and could make it easier for food manufacturers to include healthier fats.

Many processed foods are loaded with saturated and trans fats for flavor and to extend a product’s shelf life. Consuming these fats can increase the risk of cardiovascular disease, type 2 diabetes, and LDL cholesterol.

AI platform enables doctors to optimize personalized chemotherapy dose

Research team behind the PRECISE.CURATE trial (from left) Prof Dean Ho, Dr Agata Blasiak, Dr Raghav Sundar, Ms Anh Truong
Credit/Source: National University of Singapore

Based on a pilot clinical trial, close to 97% of dose recommendations by CURATE.AI were accepted by clinicians; some patients were prescribed optimal doses that were around 20% lower on average

A team of researchers from National University of Singapore (NUS), in collaboration with clinicians from the National University Cancer Institute, Singapore (NCIS) which is part of the National University Health System (NUHS), has reported promising results in using CURATE.AI, an artificial intelligence (AI) tool that identifies and better allows clinicians to make optimal and personalized doses of chemotherapy for patients.

Based on a pilot clinical trial – called PRECISE.CURATE - involving 10 patients in Singapore who were diagnosed with advanced solid tumors and predominantly metastatic colorectal cancers, clinicians accepted close to 97% of doses recommended by CURATE.AI, with some patients receiving optimal doses that were approximately 20% lower on average. These early outcomes are a promising step forward for the potential of truly personalizing oncology, where drug doses can be adjusted dynamically during treatment.

Developed by Professor Dean Ho and his team, CURATE.AI is an optimization platform that harnesses a patient’s clinical data, which includes drug type, drug dose and cancer biomarkers, to generate an individualized digital profile which is used to customize the optimal dose during the course of chemotherapy treatment.

Brain hereditary disease factor suspected

Jonasz Jeremiasz Weber, Rana Dilara Incebacak Eltemur, Priscila Pereira Sena, Huu Phuc Nguyen (from left) worked out the study together.
Credit: © Pengfei Qi

Similar to Alzheimer's, the hereditary disease Spinocerebellar Ataxia Type 17 (SCA17) leads to the demise of brain nerve cells and the premature death of those affected. The exact mechanisms of the disease are unknown, so there are no treatment approaches to date. Researchers of human genetics at the Ruhr University Bochum (RUB) around Dr. Jonasz Weber now suspects a class of protein-splitting enzymes, so-called calpaines, to contribute to the disease. In the model, the Calpaine was switched off to stop the course. The researchers report in the journal Cellular and Molecular Life Sciences.

Changed blueprint of a protein

Spinocerebellar ataxia type 17 (SCA17) is a rare, hereditary disease of the human brain. Due to the pathological change in a gene that contains the blueprint for a protein called TATA box-binding protein (TBP), the protein is formed in cells in a defective form. This also affects its function. "One consequence of this is that the protein forms detectable protein deposits in the brain and damages the nerve cells via molecular mechanisms that have not yet been fully elucidated," explains Jonasz Weber.

As a consequence, those affected by the disease develop symptoms such as movement disorders, seizures, impairment of mental performance as well as changes in nature and behavior, which are associated with the breakdown of tissues such as the cerebellum and brain stem.

IA leads the charge against multiple sclerosis

MRI image in false colors of a brain hemisphere from an MS patient (affected areas are shown in red).
 Credit: Govind Bhagavatheeshwaran, Daniel Reich / NINDS / NIH

Artificial intelligence may enable earlier diagnosis of Multiple Sclerosis, an incurable disease that attacks the central nervous system. This could improve the efficacy of treatments designed to slow its progression.

An autoimmune disease, multiple sclerosis (MS) is characterized by a breakdown of myelin, the membrane that protects the axons of neurons. Communication within the nervous system is gradually disrupted, causing increasingly severe motor and neurological damage. Although multiple sclerosis is currently incurable, treatments are available to relieve certain symptoms, particularly if the disease is discovered early; unfortunately, however, it tends to be diagnosed at a later stage.

San Diego Zoo and Its Partners Spearhead Conservation of Critically Endangered Chinese Giant Salamander

Chinese giant salamander
Credit: San Diego Zoo Wildlife Alliance

Chinese giant salamanders are well camouflaged in the rushing waters of China’s mountain river system. Spotting this critically endangered species in its native habitat is exceedingly rare, but guests at the San Diego Zoo now have a unique opportunity to take a close look at this sleek and mysterious creature—at the newly opened Denny Sanford Wildlife Explorers Basecamp. San Diego Zoo Wildlife Alliance and conservation partners, including Ocean Park Hong Kong, are working toward the goal of creating a breeding group of Chinese giant salamanders. The goal is to eventually re-establish depleted populations in the Chinese giant salamander’s native range, while at the same time educating the public about conservation of its habitat in China.

The Chinese giant salamander is the largest living amphibian on the planet, with some measuring nearly 6 feet in length. However, their elusive nature has made it difficult for biologists to study their reproductive habits. Veterinary and wildlife care specialist teams at the San Diego Zoo conducted ultrasounds on three Chinese giant salamanders, in an effort to determine their sex and better understand their overall health. Determining the sex of these individuals is critical to the creation of a conservation breeding plan to help bring this species of “living fossils” back from the brink of extinction. The technique of using ultrasound to determine sex was discovered and recommended by specialists in China and colleagues in the zoo community.

Ningaloo corals are ill-equipped to handle future climate change

Source: Curtin University

The relatively pristine coral populations of WA’s inshore Kimberley region are better equipped to survive ocean warming than the World Heritage-listed Ningaloo Marine Park, according to a new Curtin University study.

Despite previous research predicting coral species would move south to cooler waters to protect themselves, the new study – published in Molecular Ecology – has found this may not hold true on the West Coast of Australia.

The new study, which investigated coral population connectivity and adaptive capacity, has found corals growing in different reef systems in north-western Australia are genetically isolated from each other.

The findings were based on the genetic data of a reef-building coral, Acropora digitifera, sampled from five well-known reef systems. The study sought to find out how connected these reef systems are, and how resilient this coral is to different future climate scenarios in different regions.

Lead researcher PhD student Arne Adam, from the Curtin School of Molecular and Life Sciences, said climate change had caused widespread loss of species biodiversity and ecosystem productivity across the globe, particularly on tropical coral reefs. He said the results suggest corals from northern reefs in WA are isolated from each other, meaning that corals may not be able to move to more southern reef regions.

Scientists Have Found Neurons that Control Some Symptoms of Sickness

During an infection, inflammatory signals activate immune-sensitive neurons (genetically labeled in red) in the ventral medial preoptic area (VMPO) leading to the induction of fever and other sickness behaviors. All cells are labeled with a nuclear stain (blue).
Credit: Courtesy of Dulac Lab/HHMI at Harvard University

Feeling ill is about both the body and the brain. Now scientists have identified a group of neurons in mice that has ultimate control over symptoms such as fever and behaviors like seeking out warmth.

Fevers, chills, an appetite that vanishes – we can tell when we’re getting sick. Many people chalk these symptoms of illness up to the immune system fighting off infection. But there’s another player involved when we feel woefully under the weather.

“All of this is orchestrated by the brain,” says neurobiologist Catherine Dulac, who is a Howard Hughes Medical Institute Investigator at Harvard University. Now research from Dulac’s team, published in Nature, pins this broad response on a previously uncharacterized population of neurons in the brain.

How exactly the brain serves as an infection ringleader has been unclear. Earlier research had identified receptors in the brain that were required for animals to develop a fever. But fever is only part of the story. One of the bigger mysteries is: Where does ultimate control for the symptoms and behaviors associated with sickness lie?

Dulac, her postdoctoral fellow, Jessica A. Osterhout, and colleagues injected mice with molecules that mimic bacterial or viral infections to investigate that question. As the mice’s immune systems reacted to these inflammatory molecules, the researchers homed in on which neurons jumped into action. The team watched neurons’ gene expression through single-cell RNA sequencing and mapped the whereabouts of those neurons using a visualization technique called MERFISH, which was developed in the lab of HHMI Investigator Xiaowei Zhuang at Harvard, a collaborator in this work.

Carbon Dioxide Glaciers Are Moving at Mars’ South Pole

Perspective view of the South Polar Cap of Mars using Viking imagery draped over topography from the Mars Orbiter Laser Altimeter. White ice is a residual carbon dioxide cap that resides on top of and protects the much thicker CO2 glaciers. The surrounding terrain is composed of red dust that overlies the mountains in the background and the 4-kilometer-thick H2O ice cap that supports the CO2 glaciers.
  Credit: NASA data visualized using JMARS.

Glaciers of carbon dioxide are moving, creating deposits kilometers thick today across the south polar region of Mars, something that could have been going on more than 600,000 years, a paper by Planetary Science Institute Research Scientist Isaac Smith says.

“The CO2 deposits that were first identified in 2011 turn out to be flowing today, just like glaciers on Earth,” said Smith, lead author of “Carbon Dioxide Ice Glaciers at the South Pole of Mars” that appears in the Journal for Geophysical Research - Planets.

“Approximately 600,000 years ago CO2 ice started forming at the Martian south pole. Due to climate cycles, the ice has increased in volume and mass several times, interrupted by periods of mass loss through sublimation,” Smith said. “If the ice had never flowed, then it would mostly be where it was originally deposited, and the thickest ice would only be about 45 meters thick. Instead, because it flowed downhill into basins and spiral troughs – curvilinear basins – where it ponded, it was able to form deposits reaching one kilometer thick.

The Earth moves far under our feet: New study shows Earth’s inner core oscillates

The Earth’s inner core — a hot, dense ball of solid iron the size of Pluto — has been shown to move and/or change over decades.
Credit: USC Graphic/Edward Sotelo

USC scientists have found evidence that the Earth’s inner core oscillates, contradicting previously accepted models that suggested it consistently rotates at a faster rate than the planet’s surface.

Their study, published in Science Advances, shows that the inner core changed direction in the six-year period from 1969-74, according to the analysis of seismic data. The scientists say their model of inner core movement also explains the variation in the length of day, which has been shown to oscillate persistently for the past several decades.

“From our findings, we can see the Earth’s surface shifts compared to its inner core, as people have asserted for 20 years,” said John Vidale, co-author of the study and Dean’s Professor of Earth Sciences at USC Dornsife College of Letters, Arts and Sciences. “However, our latest observations show that the inner core spun slightly slower from 1969-71 and then moved in the other direction from 1971-74. We also note that the length of the day grew and shrank as would be predicted.

“The coincidence of those two observations makes oscillation the likely interpretation.”