A Tiny Spot Leads to a Large Advancement in Nano-processing, Researchers Reveal

A conceptual illustration of single-shot laser processing by an annular-shaped radially polarized beam, focused on the back surface of a glass plate.
Illustration Credit: ©Y. Kozawa et al.

Focusing a tailored laser beam through transparent glass can create a tiny spot inside the material. Researchers at Tohoku University have reported on a way to use this small spot to improve laser material processing, boosting processing resolution.

Laser machining, like drilling and cutting, is vital in industries such as automotive, semiconductors, and medicine. Ultra-short pulse laser sources, with pulse widths from picoseconds to femtoseconds, enable precise processing at scales ranging from microns to tens of microns. But recent advancements demand even smaller scales, below 100 nanometers, which existing methods struggle to achieve.

The researchers focused on a laser beam with radial polarization, known as a vector beam. This beam generates a longitudinal electric field at the focus, producing a smaller spot than conventional beams.

Scientists have identified this process as promising for laser processing. However, one drawback is that this field weakens inside the material due to light refraction at the air-material interface, limiting its use.

A new type of cooling for quantum simulators

Tiantian Zhang and Maximilian Prüfer discussing measurements in the quantum lab
Photo Credit: Courtesy of Technische Universität Wien

Quantum experiments always have to deal with the same problem, regardless of whether they involve quantum computers, quantum teleportation or new types of quantum sensors: quantum effects break down very easily. They are extremely sensitive to external disturbances - for example, to fluctuations caused simply by the surrounding temperature. It is therefore important to be able to cool down quantum experiments as effectively as possible.

At TU Wien (Vienna), it has now been shown that this type of cooling can be achieved in an interesting new way: A Bose-Einstein condensate is split into two parts, neither abruptly nor particularly slowly, but with a very specific temporal dynamic that ensures that random fluctuations are prevented as perfectly as possible. In this way, the relevant temperature in the already extremely cold Bose-Einstein condensate can be significantly reduced. This is important for quantum simulators, which are used at TU Wien to gain insights into quantum effects that could not be investigated using previous methods.

Researchers Identify Microbes That Help Plants Thwart Parasite

Sorghum crops in sub-Saharan Africa suffer heavy losses from the parasitic plant witchweed (Striga hermonthica). A new study shows how soil microbes can help protect sorghum from this pest and could be the basis for a soil probiotic treatment.
Photo Credit: Sabine

Bacteria that could help one of Africa’s staple crops resist a major pest have been identified by researchers at the University of California, Davis. Their findings, published in Cell Reports, could improve yields of sorghum, a mainstay of food and drink in West and East African countries.

About 20 percent of Africa’s sorghum crop is lost due to witchweed (Striga hermonthica), a parasitic plant that steals nutrients and water by latching onto the plant’s roots.

In a new study, UC Davis researchers show that soil microbes induce changes in sorghum roots that make the plant more resistant to infection by witchweed. They identified specific strains of bacteria that trigger these resistance traits and could be applied as a soil “probiotic” to improve sorghum yields in future.

“These microbes have great promise as soil additives that can help farmers grow sorghum successfully in sub-Saharan Africa,” said Siobhan Brady, a professor in the Department of Plant Biology and Genome Center and a senior author on the paper. 

Scientists propose a new way to search for dark matter

(Left) The new dark matter detection proposal looks for frequent interactions between nuclei in a detector and low-energy dark matter that may be present in and around Earth. (Right) A conventional direct detection experiment looks for occasional recoils from dark matter scattering.
Image Credit: Anirban Das, Noah Kurinsky and Rebecca Leane

Ever since its discovery, dark matter has remained invisible to scientists, despite the launch of multiple ultra-sensitive particle detector experiments around the world over several decades. 

Now, physicists at the Department of Energy’s (DOE) SLAC National Accelerator Laboratory are proposing a new way to look for dark matter using quantum devices, which might be naturally tuned to detect what researchers call thermalized dark matter.

Most dark matter experiments hunt for galactic dark matter, which rockets into Earth directly from space, but another kind might have been hanging around Earth for years, said SLAC physicist Rebecca Leane, who was an author on the new study. 

“Dark matter goes into the Earth, bounces around a lot, and eventually just gets trapped by the gravitational field of the Earth,” Leane said, bringing it into an equilibrium scientists refer to as thermalized. Over time, this thermalized dark matter builds up to a higher density than the few loose, galactic particles, meaning that it could be more likely to hit a detector. Unfortunately, thermalized dark matter moves much more slowly than galactic dark matter, meaning it would impart far less energy than galactic dark matter – likely too little for traditional detectors to see.

New machine to enhance understanding of nuclear weapons’ behavior

Bob Webster, deputy Laboratory director for Weapons (far right); Mike Furlanetto, Scorpius Advanced Sources and Detection project director (center); and Geoffrey Zehnder, project engineer (far left); discuss the prototype module Lab employees constructed for Scorpius' first accelerator cells and modules.
Photo Credit: Courtesy of Los Alamos National Laboratory

On March 7, assembly began at Los Alamos National Laboratory on a groundbreaking machine that will allow scientists to use real plutonium in experiments while studying the conditions immediately before the nuclear phase of a weapon's functioning. The machine will prove instrumental in the Laboratory's stockpile stewardship mission, which ensures the safety, security and reliability of the nation's nuclear weapons through computational tools and engineering test facilities, rather than underground testing.

Although the plutonium used will never reach criticality — the condition that forms a self-sustaining nuclear reaction — the tests performed as part of the Scorpius Advanced Sources and Detection (ASD) project will provide essential knowledge about how the key element in nuclear weapons behaves.

The components being built will be the first two accelerator cell modules for Scorpius.

"This means we have officially started building, and I am so looking forward to seeing this experiment in my lifetime," said Bob Webster, deputy Laboratory director for Weapons.

New Genetic Analysis Tool Tracks Risks Tied to CRISPR Edits

UC San Diego researchers have created a new system that reveals specific categories of potentially risky mutations resulting from CRISPR edits. This high magnification image reveals CRISPR-based DNA transcription of the homothorax gene in fruit fly embryos.
Image Credit: Bier Lab, UC San Diego

Since its breakthrough development more than a decade ago, CRISPR has revolutionized DNA editing across a broad range of fields. Now scientists are applying the technology’s immense potential to human health and disease, targeting new therapies for an array of disorders spanning cancers, blood conditions and diabetes.

In some designed treatments, patients are injected with CRISPR-treated cells or with packaged CRISPR components with a goal of repairing diseased cells with precision gene edits. Yet, while CRISPR has shown immense promise as a next-generation therapeutic tool, the technology’s edits are still imperfect. CRISPR-based gene therapies can cause unintended but harmful “bystander” edits to parts of the genome, at times leading to new cancers or other diseases.

Next-generation solutions are needed to help scientists unravel the complex biological dynamics behind both on- and off-target CRISPR edits. But the landscape for such novel tools is daunting, since intricate bodily tissues feature thousands of different cell types and CRISPR edits can depend on many different biological pathways.

Researchers a step closer to a cure for HIV

HIV, the AIDS virus (yellow), infecting a human cell
Image Credit: National Cancer Institute

A new study involving University of Bristol researchers has shown a virus-like particle (HLP) can effectively 'shock and kill' the latent HIV reservoir.

By 2030, the World Health Organization (WHO), the Global Fund and UNAIDS are hoping to end the human immunodeficiency virus (HIV) and AIDS epidemic. An international team of researchers led by Professor Eric Arts from the Schulich School of Medicine & Dentistry, Canada, and Dr Jamie Mann, Senior Lecturer at the University of Bristol, has brought us another step closer to meeting this goal, by finding an effective and affordable targeted treatment strategy for an HIV cure. 

In a first, the study published in Emerging Microbes and Infections demonstrated the team's patented therapeutic candidate. The HIV-virus-like-particle (HLP), is 100 times more effective than other candidate HIV cure therapeutics for people living with chronic HIV on combined antiretroviral therapy (cART). If successful in clinical trials, HLP could be used by millions of people living around the world to free them of HIV. This study was done using blood samples from people living with chronic HIV. 

HLPs are dead HIV particles hosting a comprehensive set of HIV proteins that increase immune responses without infecting a person. When compared with other potential cure approaches, HLP is an affordable biotherapeutic and can be administered by intramuscular injection – similar to the seasonal flu vaccine. 

Two-Way Cell-based Treatment Repairs Muscle After Rotator Cuff Injury

A combination of mobilizing agent, designed to “push” pro-healing cells into the blood, and SDF-1a, designed to “pull” the cells into the injury site, leads to an increase in muscle regeneration following a rotator cuff tear. Muscle regeneration was characterized based on the number of centrally located nuclei (marked with the white arrows).
Image Credit: Courtesy of the researchers / Georgia Institute of Technology

A team of Georgia Tech researchers has introduced a new therapeutic system to offset the poor clinical outcomes often associated with common rotator cuff surgery.

It’s the kind of surgery that makes headlines whenever a famous athlete is sidelined with a torn rotator cuff. Major League Baseball All-Star pitchers Clayton Kershaw and Justin Verlander, for example, both had rotator cuff surgeries and made successful comebacks.

For those of us who can’t throw baseballs 95 miles an hour, the rotator cuff may tear over time from repeated overhead motions (painters and carpenters, for instance). Or an injury can occur as we age and our body’s tissues naturally degenerate. And although rotator cuff injuries are common, they can be serious, leading to muscle degeneration after surgery.

Now, two professors from the Wallace H. Coulter Department of Biomedical Engineering, a joint department of Georgia Tech and Emory University, have addressed the problem with a novel cell-based dual treatment, which they describe in a study published recently in the journal Tissue Engineering.

Climate change will see Australia’s soil emit CO2 and add to global warming

Australian Outback
Photo Credit: Nathan March

New Curtin University research has shown the warming climate will turn Australia’s soil into a net emitter of carbon dioxide (CO2), unless action is taken.

Soil helps to keep the planet cool by absorbing carbon, however as the climate gets warmer its ability to retain carbon decreases — and in some instances can start to release some carbon back into the air.

A global research team — led by Professor Raphael Viscarra Rossel from Curtin’s School of Molecular and Life Sciences— predicted the changes in the amount of carbon in Australia’s soil between now and the year 2100.

To do so, the team ran simulations using three different paths for society: an eco-focused ‘sustainable’ scenario, a ‘middle-of-the-road’ scenario and another which predicted a continued reliance on ‘fossil-fueled development’.

It found Australian soil will be a net emitter and could account for 8.3 per cent of Australia’s total current emissions under the ‘sustainable’ scenario and more than 14 per cent by 2045 under the ‘middle-of-the-road’ and ‘fossil-fueled’ scenarios.

Study explores severe hurricanes and coral reef sponge recolonization

For the study, scuba divers collected small samples of the thin purple morphotype sponges 14 and 22 months after the two Category 5 hurricanes in St. Thomas.
Photo Credit: Karli Hollister

Named for its ropy-looking long branches, Aplysina cauliformis, a coral reef sponge, provides a critical 3D habitat for marine organisms and helps to stabilize the foundation of coral reefs. However, these upright branching sponges are highly susceptible to breaking during storms, which increases sponge fragmentation and contributes to population clonality and inbreeding.

Many sponges can survive severe damage and undergo frequent fragmentation, which is considered a mechanism for asexual reproduction. While fragmentation is a commonly utilized reproductive strategy in rope sponges, they also can reproduce sexually by producing larvae. How and whether they recolonize following extreme weather events is critical for the restoration and resilience of coral reef ecosystems.

Hurricanes Irma and Maria – both in 2017 – were two rapid succession storms that provided researchers from Florida Atlantic University’s Harriet L. Wilkes Honors College and Harbor Branch Oceanographic Institute, and collaborators from the University of the Virgin Islands, the University of Mississippi and the University of Alabama, with a unique opportunity to address a priority concern – the resilience of coral reef sponge populations after severe hurricanes.