New Stanford chip-scale laser isolator could transform photonics

From left, Alexander White, Geun Ho Ahn, and Jelena Vučković with the nanoscale isolator.
Photo Credit: Hannah Kleidermacher

Using well-known materials and manufacturing processes, researchers have built an effective, passive, ultrathin laser isolator that opens new research avenues in photonics.

Lasers are transformational devices, but one technical challenge prevents them from being even more so. The light they emit can reflect back into the laser itself and destabilize or even disable it. At real-world scales, this challenge is solved by bulky devices that use magnetism to block harmful reflections. At chip scale, however, where engineers hope lasers will one day transform computer circuitry, effective isolators have proved elusive.

Against that backdrop, researchers at Stanford University say they have created a simple and effective chip-scale isolator that can be laid down in a layer of semiconductor-based material hundreds of times thinner than a sheet of paper.

“Chip-scale isolation is one of the great open challenges in photonics,” said Jelena Vučković, a professor of electrical engineering at Stanford and senior author of the study appearing Dec. 1 in the journal Nature Photonics.

“Every laser needs an isolator to stop back reflections from coming into and destabilizing the laser,” said Alexander White, a doctoral candidate in Vučković’s lab and co-first author of the paper, adding that the device has implications for everyday computing, but could also influence next-generation technologies, like quantum computing.

Small fish could play big role in fight against malnutrition

 Dagaa, a small pelagic fish, is the largest share of the catch around Lake Victoria in East Africa. Photo Credit: Kathryn Fiorella

According to new research, inexpensive, small fish species caught in seas and lakes in developing countries could help close nutritional gaps for undernourished people, and especially young children, according to new research.

The study, “Small Pelagic Fish Supply Abundant and Affordable Micronutrients to Low- and Middle-Income Countries,” published Dec. 1 in Nature Food.

The researchers found that fish such as herring, sardines and anchovies – known as pelagic fish, meaning they inhabit upper layers of open sea – were the cheapest nutritious fish in 72% percent of the countries.

They also found targeting small pelagic fish could help close nutrient gaps in sub-Saharan Africa, where nutrient deficiencies are rising and children under 5 years consume just 38% of recommended seafood intake. While cheap and nutritious, these small fish are also already caught in sufficient numbers. Just 20% of the current small pelagic fish catch could meet the recommended dietary fish intakes for all children under 5 who live near coastlines.

Hibernating Corals and the Microbiomes That Sustain Them

A microscope image of Northern star coral with its polyps extended.
Photo Credit: Alicia Schickle, Roger Williams University

As winter approaches, many species of animals — from bears and squirrels to parasitic wasps and a few lucky humans — hunker down for some needed rest. The northern star coral (Astrangia poculata) also enters a hibernating state of dormancy, or quiescence, during this time. But what happens to its microbiome while it’s sleeping?

A study led by University of California, Davis, Assistant Professor Anya Brown found that microbial communities shift while this coral enters dormancy, providing it an important seasonal reset. The work may carry implications for coral in warmer waters struggling with climate change and other environmental issues.

“Dormancy, at its most basic, is a response to an environmental stressor — in this case, cold stress,” said Brown, who is part of the UC Davis Bodega Marine Laboratory in the Department of Evolution and Ecology. “If we understand more about this recovery period, it might help us understand what microbes may be responsible for recovering coral in warmer tropical systems.”

Researchers Develop Strategy to Thermally Stabilize Microneedle Vaccine Technology

Visual of the researcher's microneedle vaccine technology concept.
Illustration Credit: Thahn Nguyen

Researchers use sugar molecules to help eliminate the need for cold-chain storage, a common logistical hurdle for vaccine distribution

Researchers in the Department of Biomedical Engineering —a shared department between the UConn Schools of Dental Medicine, Medicine, and Engineering—unlocked a new strategy using sugar molecules to thermally stabilize their existing microneedle vaccine technology, eliminating the need for cold-chain storage.

Associate Professor Thanh Duc Nguyen from the Departments of Mechanical Engineering and Biomedical Engineering in the School of Engineering, reported this new development in a recent issue of Advanced Materials Technology. The work was led by Dr. Khanh Tran, Nguyen’s former UConn Ph.D. student currently at the Massachusetts Institute of Technology, and Dr. Tyler Gavitt, former UConn Ph.D. student currently at Duke University. Gavitt was a student of Associate Professor Steven Szczepanek in the Department of Pathobiology and Veterinary Science in the College of Agriculture, Health, and Natural Resources at UConn.

Typically, vaccinations against infectious diseases like COVID-19 require multiple painful, expensive and inconvenient injections, including a prime and several booster shots. The UConn researcher’s technology creates a self-administered microneedle patch which could be self-administered and only requires a single-time administration into skin—similar to a nicotine patch—to perform a release profile of vaccines, simulating the effect of multiple injections.

Development of the immune system before and after birth

What influence does a premature birth have on the development of the immune system? And how can the immune system be supported to ensure an optimal start in life? The researchers in the SFB/TRR PILOT are dealing with these and many other questions.
Photo Credit: University Medical Centre Freiburg

The newborn's immune system is suddenly confronted with microorganisms, food and numerous environmental influences at birth. How do the baby's immune cells prepare for this moment during pregnancy and birth? How do external influences shape the immune system immediately after birth? And what influence does an event like a premature birth have? These and many other questions about the development of the child's immune system around birth are being investigated by scientists from the Facult of Medicine at the University of Freiburg together with researchers from the LMU Munich, the University Hospital RWTH Aachen and other institutions in the Collaborative Research Center/Transregio “Perinatal Development of Immune Cell Topology (PILOT).” PILOT was approved by the German Research Foundation (DFG) on November 25, 2022, and will be funded with a total of 12 million euros for an initial period of four years starting January 1, 2023.

Mammoth problem with extinction timeline

Cameron Schwalbach, paleontology collections manager for the Cincinnati Museum Center’s Geier Collections and Research Center, and UC assistant professor Joshua Miller examine a mammoth skull. Photo Credit: Andrew Higley/UC Marketing + Brand

Exactly when mammoths went extinct has fascinated paleontologists for generations, perhaps because their decline coincided with the arrival of people to North and South America.

So, it’s only natural to wonder if humans more than contributed to the extinction of these enormous beasts of the ice age more than 10,000 years ago.

A University of Cincinnati paleontologist refutes the latest timeline published in 2021 in the journal Nature that suggested mammoths met their end much more recently than we believed. An international team of researchers examined environmental DNA of mammoth remains and more than 1,500 arctic plants to conclude that a wetter climate quickly changed the landscape from tundra grassland steppe to forested wetlands that could not support many of these big grazing animals, driving mammoths to extinction as recently as 3,900 years ago.

But in a rebuttal paper to be published Dec. 1 in Journal Nature, UC College of Arts and Sciences assistant professor Joshua Miller and co-author Carl Simpson at the University of Colorado Boulder argue that the environmental DNA used to establish their updated timeline is more complex than previously recognized.

New clues about how carbon dioxide affects bumble bee reproduction

In addition to inducing a calming effect, carbon dioxide also can trigger a range of other physiological responses in bumble bees, according to a Penn State researcher.
Photo Credit: Eduardo Goody

While a beekeeper puffing clouds of carbon dioxide into a hive to calm the insects is a familiar image to many, less is known about its other effects on bees. A recent study revealed clues about how the chemical compound affects bee physiology, including reproduction.

The research team, led by an entomologist in Penn State’s College of Agricultural Sciences, set out to disentangle how carbon dioxide seems to bypass diapause, a phase similar to hibernation during which bees sleep over the winter, to trigger the reproductive process in bumblebee queens.

The researchers found that carbon dioxide first induced a change in metabolism, which then triggered secondary effects on reproduction. The findings, recently published in Insect Biochemistry and Molecular Biology, were contrary to previous hypotheses.

“Previously, it was believed that CO2 directly affected reproduction, but this study is some of the first evidence showing this is likely not the case,” said Etya Amsalem, associate professor of entomology. “We found that CO2 changes the way macronutrients are stored and reallocated in the body. The fact that the reproductive process is then kickstarted is just an artifact of these processes.”

Smallest mobile lifeform created

The origin of all biological movements, including walking, swimming, or flying, can be traced back to cellular movements; however, little is known about how cell motility arose in evolution.

A research team led by graduate student Hana Kiyama, from the Graduate School of Science at Osaka City University, and Professor Makoto Miyata, from the Graduate School of Science at Osaka Metropolitan University, introduced seven proteins, believed to be directly involved in allowing Spiroplasma bacteria to swim into a synthetic bacterium named syn3—through genetic engineering. syn3 was designed and chemically synthesized to have the smallest genomic DNA possible including the minimum essential genetic information required for growth from the smallest genomes of naturally occurring Mycoplasma bacteria.

“Studying the world’s smallest bacterium with the smallest functional motor apparatus could be used to develop movement for cell-mimicking microrobots or protein-based motors,” said Professor Miyata.

This genetically re-engineered syn3 changed from its normal spherical shape into a spiraling helix, which was able to swim by reversing the helix’s direction just like Spiroplasma. Further investigation revealed that only two of these newly added proteins were required to make syn3 capable of minimal swimming.

“Our swimming syn3 can be said to be the ‘smallest mobile lifeform’ with the ability to move on its own,” said Professor Miyata. “The results of this research are expected to advance how we understand the evolution and origins of cell motility.”

Published:

In the journal Science Advances

Source/Credit:  Osaka Metropolitan University

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Commercial Dishwashers Destroy Protective Layer in Gut

Rinse aids in commercial dishwashers often contain alcohol ethoxylate. This substance damages the intestinal epithelium, which can lead to chronic diseases.

Residue from rinse agents is left behind on dishes after they are cleaned in professional-grade dishwashers. This damages the natural protective layer in the gut and can contribute to the onset of chronic diseases, as demonstrated by researchers working with organoids at the Swiss Institute of Allergy and Asthma Research.

Whether it’s at a restaurant, at school or in the barracks, commercial dishwashers help plates, glasses and cutlery become squeaky clean and dry in a matter of minutes. These practical appliances come with risks, however, as was recently discovered in a new study by researchers at the Swiss Institute of Allergy and Asthma Research (SIAF), an associated institute of the University of Zurich (UZH). One ingredient in particular found in commercial rinse agents has a toxic effect on the gastrointestinal tract.

Chemical residue on clean plates

A typical cycle in a commercial dishwasher involves circulating hot water and detergent for around 60 seconds at high pressure. Afterwards, there is a second 60-second washing and drying cycle in which water and a rinse agent are applied. “What’s especially alarming is that in many appliances, there’s no additional wash cycle to remove the remaining rinse aid,” says Cezmi Akdis, UZH professor of experimental allergology and immunology and director of the SIAF, who led the study. “This means that potentially toxic substances remain on the dishes, where they then dry in place.” When the dishes are used the next time, this dried chemical residue can easily end up in the gastrointestinal tract.

Better Than a Hole in the Head

Just as blood pressure informs heart health, intracranial pressure (ICP) helps indicate brain health. ICP sensing is the burgeoning focus of Jana Kainerstorfer's biomedical optics lab at Carnegie Mellon University. Her team is working to modernize ICP sensing approaches, which historically have been invasive and risky. Their noninvasive alternatives will ease the risk of infection, pain and medical expenses, as well as present new monitoring capabilities for patients with an array of brain injuries and conditions, from stroke to hydrocephalus.

Investigating pressure levels in the brain is a laborious task for health professionals and hasn't progressed much since the 1960s. Current practice involves drilling a hole into a patient's skull and placing a probe inside for continuous monitoring of ICP levels. It comes with the risk of infection and damaging the brain itself, and while valuable data is to have, ICP measurement is reserved only for the most critical of situations.

"At the core of it, what we've done is build a sensor alternative that doesn't require drilling a hole into the patient's head," said Kainerstorfer, an associate professor of biomedical engineering. "We recently published two papers that explore the use of optical sensors on the forehead for noninvasive ICP monitoring, using near-infrared spectroscopy and diffuse correlation spectroscopy. Both approaches represent huge strides in improving the patient experience and providing better tools to monitor pressure levels in the brain, which can be a key variable in both diagnosis and treatment decisions."