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Comment by Dr. Krishna Kumari Challa on December 4, 2024 at 10:39am

Seeing through the mystery of an X-ray emissions mechanism

Scientists who study X-rays, lightning and similar phenomena have observed something curious: In lab experiments replicating these occurrences, electrons accelerated between two electrodes can be of a higher energy than the voltage applied.

This defies an assumption in physics that the energy of the electrons should correspond with the voltage applied.

Recently, a team of  researchers used mathematical modeling to explain the underlying mechanism at play. They published their results in Physical Review Letters.

Through mathematical modeling, they  demonstrated that an energy feedback process is responsible for this occurrence.

According to them when the electrons interact with the material of the electrode, they emit X-rays, which are made of photons—massless, charge-less particles that comprise light. Some of these photons propagate backward, enabling more electrons to release from the other electrode.

A small group of these electrons have energy corresponding to the original energy. Then they accelerate again, and the process continues through several cycles. The researchers modeled this very high energy process.

Their model also helped explain why electrodes of different shapes and materials produced this effect to varying degrees. We get maximum effect when we have flat electrodes, and a minimized effect when the electrodes are needle-like. 

This makes sense, because the large surface areas of the flat electrodes are good for the interaction between the electrons and photons and the way they bounce back and forth. When the surface area is reduced, the effect is minimized.

The researchers also examined via simulation and modeling how the phenomenon emerges with different materials.

Tungsten is the standard material used for X-ray production, and we know it's a good material for this. It is a robust material for electron production used in current in X-ray machines.

The researchers said that their findings may be useful for the development of new ways of producing X-rays in the future. Specifically, they said that the work may stimulate new research on the production of energetic electrons from solid materials, potentially making X-rays machines faster and more light weight and compact.

Victor P. Pasko et al, Photoelectric Feedback Mechanism for Acceleration of Runaway Electrons in Gas Discharges at High Overvoltages, Physical Review Letters (2024). DOI: 10.1103/PhysRevLett.133.235301

Comment by Dr. Krishna Kumari Challa on December 4, 2024 at 10:15am

Countdown to an ice-free Arctic: Research warns of accelerated timelines

The first summer on record that melts practically all of the Arctic's sea ice, an ominous milestone for the planet, could occur as early as 2027.

For the first time, an international research team used computer models to predict when the first ice-free day could occur in the northernmost ocean. An ice-free Arctic could significantly impact the ecosystem and Earth's climate by changing weather patterns. 

The first ice-free day in the Arctic won't change things dramatically, the team says. It will show that we've fundamentally altered one of the defining characteristics of the natural environment in the Arctic Ocean, which is that it is covered by sea ice and snow year-round, through greenhouse gas emissions.

The findings were published Dec. 3 in the journal Nature Communications. Jahn will also present the results on Dec. 9 at the American Geophysical Union annual meeting in Washington D.C.

The researchers' projected/estimated the first ice-free Arctic day using output from over 300 computer simulations. They found that most models predicted that the first ice-free day could happen within nine to 20 years after 2023, regardless of how humans alter their greenhouse gas emissions. The earliest ice-free day in the Arctic Ocean could occur within three years.
It's an extreme scenario but a possibility based on the models. In total, nine simulations suggested that an ice-free day could occur in three to six years.

The researchers found that a series of extreme weather events could melt two million square kilometers or more of sea ice in a short period of time: A unusually warm fall first weakens the sea ice, followed by a warm Arctic winter and spring that prevents sea ice from forming. When the Arctic experiences such extreme warming for three or more years in a row, the first ice-free day could happen in late summer.

Those kinds of warm years have already happened.

But there's also good news: A drastic cut in emissions could delay the timeline for an ice-free Arctic and reduce the time the ocean stays ice-free, according to the study.

Céline Heuzé et al, The first ice-free day in the Arctic Ocean could occur before 2030, Nature Communications (2024). DOI: 10.1038/s41467-024-54508-3 , dx.doi.org/10.1038/s41467-024-54508-3

Comment by Dr. Krishna Kumari Challa on December 4, 2024 at 9:56am

Following this, daily solar radiation was the second most important factor contributing to rice quality changes (higher solar radiation leading to lower HRR), then daily precipitation (less precipitation corresponding to lower HRR) and lastly daytime vapor pressure deficit (beyond a threshold of 0.5–1 kPa, HRR declines).
The average rice quality across all sites and years for China had a HRR of ~62%, but reduced by 1.45% every decade. In Japan, the average HRR was slightly higher at ~66%, with a prominent rate of decline of 7.6% every decade.

In both countries, there is a strong gradient of diminished rice quality from northern to southern provinces and prefectures, likely linked to southern regions being closer to the equator and therefore experiencing higher nighttime temperatures.
This research is important as projections under both moderate and high emissions scenarios suggest rice quality will continue to decline in the decades to come as climate change progresses.
Given all of this, the likelihood of rice cultivars adapting in tandem with the rate of climate change may pose a hazard to sustainable food supplies, human nutrition and economic stability in years to come.

Xianfeng Liu et al, Warming Leads to Lower Rice Quality in East Asia, Geophysical Research Letters (2024). DOI: 10.1029/2024GL110557

Part 2

Comment by Dr. Krishna Kumari Challa on December 4, 2024 at 9:53am

Climate warming is reducing rice quality

Rice is a food staple for billions of people worldwide, with demand doubling over the past 50 years, and is predominantly grown in Asia before being exported globally. This crop is sensitive to weather conditions and, as such, understanding how yields are affected by climate change is of paramount importance to ensure sustainable food supplies into the future.

Beyond yield, the quality of rice may also be affected, determined by a combination of appearance, palatability, nutritional profile and milling properties.

Research published in Geophysical Research Letters, has highlighted a decline in rice quality in  Asia, coincident with changing temperatures.

Researchers used data collected over 35 years to explore patterns in rice quality from Japan and China. This is based upon head rice rate (HRR), which is a measure of the fraction of milled rice kernels that retain 75% of their length after milling, during which the husk and bran are removed.
The research team explored a number of climate variables via modeling to ascertain which had the greatest effect on HRR; these variables were nighttime temperature, daytime temperature, diurnal temperature, daily averaged temperature, hot days (above 30/35 °C), precipitation, precipitation frequency, soil moisture, solar radiation, cloud cover, relative humidity, daytime vapor pressure deficit, transpiration and carbon dioxide concentration.

Ultimately, the scientists determined that overnight temperatures are the main driver of reduced rice quality. In particular, as nighttime temperatures become warmer, a critical threshold for decline begins at 12 °C and 18 °C for Japan and China respectively. When flowering and grain growth occur in such conditions, rates of photosynthesis and starch accumulation in the grain decrease, leading to lower rice quality as more grains are susceptible to breakage.

Part 1

Comment by Dr. Krishna Kumari Challa on December 3, 2024 at 12:32pm

Galleri blood test can  help diagnose multiple forms of cancer

Did you know that the technology to detect more than 50 cancers with one test existed?

Single-cancer screenings are the norm. The focus is usually on three specific cancers in women (breast, colon and cervical) and two in men (prostate and colon). Lung is a focus for heavy smokers.

Screening for these cancers helps save lives. But it creates what Ofman calls a classic spotlight problem, shining the light over there while other, more aggressive cancers go unscreened.

The Galleri test doesn't target a specific area. It looks for the fingerprint, the biological signal in DNA that has been shed from cancer. It's a very specific marker and detects where that cancer is in the body.

It creates a more effective and efficient screening programme.

And unlike other cancer tests (10%) the false positive rate of the Galleri test is just 0.5%.

Source: Medical news

Comment by Dr. Krishna Kumari Challa on December 3, 2024 at 12:26pm

Countertop workers exposed to serious lung disease

Durable and attractive, engineered stone countertops are a popular feature in modern  kitchens, but the workers who build them are risking their health. A growing number of these countertop workers are developing silicosis, a serious and long-term lung disease, according to a study presented at the annual meeting of the Radiological Society of North America (RSNA).

This is a new and emerging epidemic, and we must increase awareness of this disease process so we can avoid delays in diagnosis and treatment for our patients, say the study authors.

Silicosis is caused by the inhalation of crystalline silica dust produced in construction, coal mining and other industries. The prognosis is poor, with gradually worsening lung function leading to respiratory failure. The disease also makes patients more vulnerable to infection in the lungs, chronic obstructive pulmonary disease, autoimmune disease and lung cancer.

In recent years, a resurgence of silicosis has been reported in engineered countertop workers. Engineered stone countertops are made from quartz aggregate held together with a resin binder. They contain substantially more crystalline silica than natural stone versions. Workers who cut, shape, grind and polish these countertops may be exposed to significant amounts of silica dust.

In a preliminary analysis of 21 workers, 100% were male and Hispanic with a median age of 43 years and a median exposure of 18 years. All patients were symptomatic. Patients commonly had atypical and advanced features of silicosis. Shortness of breath and cough were the most common symptoms.

Primary clinicians recognized silicosis at the initial encounter in only four of 21 cases (19%), while radiologists recognized it in seven of 21 cases (33%). Alternative diagnoses, such as infection, were initially suggested in most cases. Nearly half of the patients (48%) had atypical imaging features.

The results highlight a need for more awareness and better recognition of imaging features associated with silicosis.

Source: https://www.rsna.org/annual-meeting

Comment by Dr. Krishna Kumari Challa on December 3, 2024 at 12:21pm

Scientists discover a natural flu defense mechanism that activates in the nasal cavity during pregnancy

Scientists have discovered that pregnancy may trigger a natural immunity to boost protection against severe flu infection. Their work is published in the journal Science Advances.

Contrary to the common belief that pregnancy increases vulnerability to infections, researchers found that it strengthened an immune defense in mice, blocking the Influenza A virus from spreading to the lungs, where it can cause severe infection.

A mother needs to stay healthy to protect her developing baby, so the immune system adapts to provide stronger defenses. This fascinating response in the nasal cavity  is the body's way of adding an extra layer of protection, which turns on during pregnancy.

The researchers used a mouse model to observe how a certain type of immune cell activates in the nasal cavity of mice during pregnancy, producing a powerful molecule that boosts the body's antiviral defenses, especially in the nose and upper airways.

This natural immunity in pregnancy could change the way we think about flu protection for expectant mothers

Julia Chronopoulos et al, Pregnancy enhances antiviral immunity independent of type I IFN but dependent on IL-17–producing γδ + T cells in the nasal mucosa, Science Advances (2024). DOI: 10.1126/sciadv.ado7087

Comment by Dr. Krishna Kumari Challa on December 3, 2024 at 11:19am

Cooperative motion by atoms protects glass from fracturing

What if glass doesn't break?

We've all experienced the moment of panic when a glass slips from our hands, shattering into pieces upon hitting the ground. What if this common mishap could become a thing of the past?

Now, a new discovery by researchers  has offered insights into how glass resists breakage, potentially paving the way for highly durable, break-resistant materials. The breakthrough has wide ranging implications for glass-related industries.

Details of their findings are published in the journal Acta Materialia.

Glass, while strong, is prone to breaking when stress exceeds its tolerance, but interestingly, the movement of atoms and molecules within glass can relax internal stress, making the material more resistant to fractures.

Although we know that some atoms 'jump' into nearby empty spaces, how this process alleviates stress has long been a mystery till now.

Scientists uncovered a previously unknown mechanism of stress relaxation in ionic glass, a model system of glass now.

Their research utilized state-of-the-art synchrotron radiation experiments and computer simulations to observe atomic motions in glass on a nanosecond-to-microsecond timescale.

The team discovered that when some atoms within the glass "jump" into nearby empty spaces, surrounding groups of atoms slowly move together to fill the void. This interplay of atomic jumps and collective motion reduces internal stress, protecting the glass from breaking under external force.

The research team plans to explore whether similar atomic mechanisms operate in other types of glass. Their ultimate goal is to establish universal guidelines for designing glass with superior impact resistance, which could revolutionize applications requiring durable materials.

 Makina Saito et al, Discovery of collective nonjumping motions leading to Johari–Goldstein process of stress relaxation in model ionic glass, Acta Materialia (2024). DOI: 10.1016/j.actamat.2024.120536

Comment by Dr. Krishna Kumari Challa on December 3, 2024 at 10:37am

Proof-of-concept study demonstrates self-assembling electronics

Researchers have demonstrated a new technique for self-assembling electronic devices. The proof-of-concept work was used to create diodes and transistors, and paves the way for self-assembling more complex electronic devices without relying on existing computer chip manufacturing techniques.

The paper, "Guided Ad infinitum Assembly of Mixed-Metal Oxide Arrays from Liquid Metal," is published open access in the journal Materials Horizons.

Julia J Chang et al, Guided Ad infinitum Assembly of Mixed-Metal Oxide Arrays from Liquid Metal, Materials Horizons (2024). DOI: 10.1039/D4MH01177E

Comment by Dr. Krishna Kumari Challa on December 3, 2024 at 10:02am

New spin quantum battery can be charged without an external field

Over the past few years, some researchers have been working on alternative energy storage systems that leverage the principles of quantum mechanics. These systems, known as quantum batteries, could be more efficient and compact than conventional battery technologies, while also achieving faster charging times.

In a recent paper published in Physical Review Letters, a research group  introduced a new spin quantum battery, a battery that leverages the spin degrees of freedom of particles to store and release energy. This battery is charged in a unique and advantageous way, without the need for an external field.

This  quantum battery can be seen as the intercalation of two collections of ½-spins, the simplest possible quantum systems. By properly changing the interaction between the elements of the two chains, for example by shifting one with respect to the other, it becomes possible to trap energy into the quantum battery in a stable way.

This allows their battery to be charged via a new mechanism that does not rely on the presence of an external field.

 Riccardo Grazi et al, Controlling Energy Storage Crossing Quantum Phase Transitions in an Integrable Spin Quantum Battery, Physical Review Letters (2024). DOI: 10.1103/PhysRevLett.133.197001. On arXiv: DOI: 10.48550/arxiv.2402.09169

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