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Comment by Dr. Krishna Kumari Challa on March 7, 2024 at 10:46am

The researchers' device represents the first hydrovoltaic application of a technique called nanosphere colloidal lithography, which allowed them to create a hexagonal network of precisely spaced silicon nanopillars. The spaces between the nanopillars created the perfect channels for evaporating fluid samples and could be finely tuned to better understand the effects of fluid confinement and the solid/liquid contact area.

In most fluidic systems containing saline solutions, you have an equal number of positive and negative ions. However, when you confine the liquid to a nanochannel, only ions with a polarity opposite to that of the surface charge will remain. This means that if you allow liquid to flow through the nanochannel, you will generate current and voltages.

As the fluid ion concentration increases, so does the surface charge of the nanodevice. As a result, we can use larger fluid channels while working with higher-concentration fluids. This makes it easier to fabricate devices for use with tap or seawater, as opposed to only purified water.

Because evaporation can occur continuously over a wide range of temperatures and humidities—and even at night—there are many exciting potential applications for more efficient HV devices.

Tarique Anwar et al, Salinity-dependent interfacial phenomena toward hydrovoltaic device optimization, Device (2024). DOI: 10.1016/j.device.2024.100287

Part 2

Comment by Dr. Krishna Kumari Challa on March 7, 2024 at 10:44am

Nanodevices can produce energy from evaporating tap or seawater

Evaporation is a natural process so ubiquitous that most of us take it for granted. In fact, roughly half of the solar energy that reaches the Earth drives evaporative processes. Since 2017, researchers have been working to harness the energy potential of evaporation via the hydrovoltaic (HV) effect, which allows electricity to be harvested when fluid is passed over the charged surface of a nanoscale device.

Evaporation establishes a continuous flow within nanochannels inside these devices, which act as passive pumping mechanisms. This effect is also seen in the microcapillaries of plants, where water transport occurs thanks to a combination of capillary pressure and natural evaporation.

Although hydrovoltaic devices currently exist, there is very little functional understanding of the conditions and physical phenomena that govern HV energy production at the nanoscale.

To bridge that gap, researchers now leveraged a combination of experiments and multiphysics modeling to characterize fluid flows, ion flows, and electrostatic effects due to solid-liquid interactions, with the goal of optimizing HV devices.

 In the process, they also made a major finding: that hydrovoltaic devices can operate over a wide range of salinities, contradicting prior understanding that highly purified water was required for best performance.

Part 1

Comment by Dr. Krishna Kumari Challa on March 7, 2024 at 10:40am

Scientists use a new type of nanoparticle that can both deliver vaccines and act as an adjuvant

Many vaccines, including vaccines for hepatitis B and whooping cough, consist of fragments of viral or bacterial proteins. These vaccines often include other molecules called adjuvants, which help to boost the immune system's response to the protein.

Most of these adjuvants consist of aluminum salts or other molecules that provoke a nonspecific immune response. A team of  researchers has now shown that a type of nanoparticle called a metal organic framework (MOF) can also provoke a strong immune response, by activating the innate immune system—the body's first line of defense against any pathogen—through cell proteins called toll-like receptors.

In a study of mice, the researchers showed that this MOF could successfully encapsulate and deliver part of the SARS-CoV-2 spike protein,  while also acting as an adjuvant once the MOF is broken down inside cells.

While more work would be needed to adapt these particles for use as vaccines, the study demonstrates that this type of structure can be useful for generating a strong immune response, the researchers say.

Understanding how the drug delivery vehicle can enhance an adjuvant immune response is something that could be very helpful in designing new vaccines.

Shahad Alsaiari et al, Zeolitic Imidazolate Frameworks Activate Endosomal Toll-like Receptors and Potentiate Immunogenicity of SARS-CoV-2 Spike Protein Trimer, Science Advances (2024). DOI: 10.1126/sciadv.adj6380. www.science.org/doi/10.1126/sciadv.adj6380

Comment by Dr. Krishna Kumari Challa on March 7, 2024 at 10:36am

Model estimates who benefits most from frequent COVID-19 boosters

Patients keep asking a question : How often should I get my booster shot for COVID-19?

So scientists built a model to answer that question. They published a study describing that model and its results in the journal Nature Communications.

The model's results largely square with data on who is most at risk of bad outcomes from COVID-19: For those older than 65 or who are immunocompromised, more frequent boosters—at least annually—go further to protect against hospitalization or death. For younger populations, the benefit of frequent boosting against severe disease is more modest.

The researchers hope this model can help inform both individuals making decisions about when to get boosters as well as public health policy makers.

For those over 75 years, receiving a yearly booster reduced annual severe infections from around 1,400 cases per 100,000 people to about 1,200 cases. Bumping the booster up to twice a year dropped severe infections to just over 1,000 per 100,000.

The numbers are similar for those who are moderately or severely immunocompromised, and about half that reduction for those aged 65 to 74. For younger, healthy people, the drop is much smaller: Annual or twice-yearly boosters reduced severe infections in people aged 18 to 49 by only 14 to 26 cases per 100,000 people.

These high-risk populations benefit from more frequent boosters relative to younger and healthier individuals.

Hailey J. Park et al, Comparing frequency of booster vaccination to prevent severe COVID-19 by risk group in the United States, Nature Communications (2024). DOI: 10.1038/s41467-024-45549-9

Comment by Dr. Krishna Kumari Challa on March 7, 2024 at 10:29am

Birds, beetles, bugs could help replace pesticides

Natural predators like birds, beetles and bugs might be an effective alternative to pesticides, keeping crop-devouring pests populations down while boosting crop yields, researchers say.

Pests are responsible for around 10 percent—or 21 million metric tons—of crop losses every year, but controlling them has led to the widespread use of chemical pesticides. Could birds, spiders and beetles among other invertebrate predators do the job as well?

Researchers in Brazil, the United States and the Czech Republic analyzed past research on predator pest control and found that they helped reduce pest populations by more than 70 percent, while increasing crop yields by 25 percent.

Natural predators are good pest control agents, and their maintenance is fundamental to guaranteeing pest control in a future with imminent climate change, according to scientists.

Although the researchers did not directly compare the effectiveness of invertebrates versus pesticides, he said, the damage that pesticides cause to ecosystems and biological control was well documented, from biodiversity loss and water and soil pollution to human health risks.
The researchers found that predators were more effective at pest control in regions with greater rain variability—which is expected to increase because of climate change.

The researchers were also surprised to find that having a single species of natural predator was as effective as having multiple species.
Generally speaking, the more species there are, the better ecosystems function. But there are exceptions: a single species could do the job just as well.
Climate change and rising carbon dioxide levels affect both crop yield and pest dynamics by expanding the distribution of pests and increasing their survival rates.

Meanwhile, other studies have shown that invertebrates vital for ecosystem health are suffering a rapid decline globally.
The conservation of invertebrates "guarantees pest control and increased productivity, without damaging ecosystems".
Source: AFP and other news agencies
https://phys.org/news/2024-03-birds-beetles-bugs-pesticides.html?ut...

https://phys.org/tags/biological+control/

Comment by Dr. Krishna Kumari Challa on March 7, 2024 at 10:04am

Scientists CT scanned thousands of natural history specimens, which you can access for free

Natural history museums have entered a new stage of scientific discovery and accessibility with the completion of openVertebrate (oVert), a five-year collaborative project among 18 institutions to create 3D reconstructions of vertebrate specimens and make them freely available online.

Researchers published a summary of the project in the journal BioScience in which they review the specimens that have been scanned to date and offer a glimpse of how the data might be used to ask new questions and spur the development of innovative technology.

Scientists, teachers, students and artists around the world are using these data remotely now.

David Blackburn et al, Increasing the impact of vertebrate scientific collections through 3D-imaging: the openVertebrate (oVert) Thematic Collections Network, BioScience (2023). DOI: 10.1093/biosci/biad120. academic.oup.com/bioscience/ad … osci/biad120/7615104

Comment by Dr. Krishna Kumari Challa on March 6, 2024 at 11:57am

New 'Water Batteries' Are Cheaper, Recyclable, And Won't Explode

Water and electronics don't usually mix, but as it turns out, batteries could benefit from some H₂O.

By replacing the hazardous chemical electrolytes used in commercial batteries with water, scientists have developed a recyclable 'water battery' – and solved key issues with the emerging technology, which could be a safer and greener alternative.

'Water batteries' are formally known as aqueous metal-ion batteries. These devices use metals such as magnesium or zinc, which are cheaper to assemble and less toxic than the materials currently used in other kinds of batteries.

Batteries store energy by creating a flow of electrons that move from the positive end of the battery (the cathode) to the negative end (the anode). They expend energy when electrons flow the opposite way. The fluid in the battery is there to shuttle electrons back and forth between both ends.

In a water battery, the electrolytic fluid is water with a few added salts, instead of something like sulfuric acid or lithium salt.

Crucially, the team behind this latest advancement came up with a way to prevent these water batteries from short-circuiting. This happens when tiny spiky metallic growths called dendrites form on the metal anode inside a battery, busting through battery compartments.

https://onlinelibrary.wiley.com/doi/10.1002/adma.202400237

Comment by Dr. Krishna Kumari Challa on March 6, 2024 at 11:56am

Physicists Reveal a Strange Form of Crystal Where Electrons Can't Move

In a search for novel materials that can contain bizarre new states of matter, physicists led an experiment that forced free-roaming electrons to stay in place. While the phenomenon has been seen in materials where electrons are constrained to just two dimensions, this is the first time it's been observed in a three-dimensional crystal metal lattice, known as a pyrochlore. The technique gives researchers a new tool for studying the less conventional activities of plucky, charge-carrying particles.

https://www.nature.com/articles/s41567-023-02362-3

Comment by Dr. Krishna Kumari Challa on March 6, 2024 at 11:28am

Organoids grown from amniotic fluid
For the first time, researchers have grown organoids — 3D bundles of cells that mimic tissue — directly from cells taken from ongoing pregnancies. The cells were extracted from amniotic fluid around growing fetuses between the 16th and 34th weeks of gestation during standard procedures independent of the study. The team grew organoids from three organs — the small intestines, kidneys and lungs — and also modelled congenital diaphragmatic hernia, a disorder where the diaphragm fails to develop correctly, using cells from samples affected by the disorder. Unlike organoids made from pluripotent stem cells, the amniotic fluid cells already have an organ identity. “There is no reprogramming, no manipulation,” says stem-cell biologist and study co-author Mattia Gerli, “we’re just allowing the cells to express their potential.”

https://www.nature.com/articles/d41586-024-00656-x?utm_source=Live+...

https://www.nature.com/articles/s41591-024-02807-z?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa on March 6, 2024 at 10:03am

The Arctic could become 'ice-free' within a decade, say scientists

The Arctic could see summer days with practically no sea ice as early as the next couple of years, according to a new study .

The findings, published in the journal Nature Reviews Earth & Environment, suggest that the first ice-free day in the Arctic could occur over 10 years earlier than previous projections, which focused on when the region would be ice-free for a month or more. The trend remains consistent under all future emission scenarios.

By mid-century, the Arctic is likely to see an entire month without floating ice during September, when the region's sea ice coverage is at its minimum. At the end of the century, the ice-free season could last several months a year, depending on future emissions scenarios. For example, under a high-emissions, or business-as-usual, scenario, the planet's northernmost region could become consistently ice-free even in some winter months.

For scientists, an ice-free Arctic doesn't mean there would be zero ice in the water.

Instead, researchers say the Arctic is ice-free when the ocean has less than 1 million square kilometers (386,000 square miles) of ice. The threshold represents less than 20% of what the region's seasonal minimum ice cover was in the 1980s. In recent years, the Arctic Ocean had around 3.3 million square kilometers of sea ice area at its minimum in September.

Projections of an ice-free Arctic Ocean, Nature Reviews Earth & Environment (2024). DOI: 10.1038/s43017-023-00515-9

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