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Comment by Dr. Krishna Kumari Challa on January 17, 2023 at 11:09am

Mathematics at the speed of light

Researchers created a nanostructured surface capable of solving equations using light. This discovery opens exciting new opportunities in the field of analog processing based on optical metasurfaces.

The world's ever-growing needs for efficient computing have been driving researchers from diverse research fields to explore alternatives to the current digital computing paradigm. The processing speed and energy efficiency of standard electronics have become limiting factors for novel disruptive applications entering our everyday life, such as artificial intelligence, machine learning, computer vision, and many more. In this context, analog computing has resurfaced and regained significant attention as a complementary route to traditional architectures.

Optical analog processing refers to the use of light to perform analog computations, as opposed to traditional electronic methods which use electricity. One major benefit of using light to perform specific computing tasks is that it can operate at much higher speeds than electronic methods, as the computation is performed at the speed of light traveling through very thin nanostructured surfaces called metasurfaces. In addition, optical analog processing can be more energy efficient than electronic methods, since it does not generate heat in the same way that electronic circuits do. This makes it well-suited for use in high-performance computing applications where speed and energy efficiency are important.

The  researchers developed a thin dielectric nanostructure, called a metagrating, and incorporated a semi-transparent mirror into the sample to continuously send back the signal to the nanostructures, each time multiplied by the metagrating scattering matrix.

They used  a special optimization technique to design the unit cell of the nanostructured array, or metagrating, that can perform the desired matrix multiplication. Each mathematical problem requires a specific design for the metagrating, but in theory one could engineer a surface with multiple parallel gratings to solve several integral equations in parallel.

These results demonstrate the possibility of solving complex mathematical problems and a generic matrix inversion at speeds that are far beyond those of the typical digital computing methods. Indeed, the solution converges in about 349 fs (i.e., less than one thousand-millionth of a second), orders of magnitude faster than the clock speed of a conventional processor.

Andrea Cordaro et al, Solving integral equations in free space with inverse-designed ultrathin optical metagratings, Nature Nanotechnology (2023). DOI: 10.1038/s41565-022-01297-9

Comment by Dr. Krishna Kumari Challa on January 16, 2023 at 12:08pm

Does Light Experience Time?

Comment by Dr. Krishna Kumari Challa on January 16, 2023 at 10:06am

Building blocks of life found in meteorite that crash landed on Earth

New research has been published on the organic analysis of the Winchcombe meteorite that crash landed onto a driveway in Winchcombe, Gloucestershire in 2021. The research found organic compounds from space that hold the secrets to the origin of life.

In the study, the analysis found a range of organic matter, which reveals that the meteorite was once from part of an asteroid where liquid water occurred, and if it that asteroid had been given access to the water, a chemical reaction could have occurred leading to more molecules turning into amino acids and protein—the building blocks of life. The Winchcombe meteorite is a rare carbon rich chondritic meteorite (approximately 4% of all recovered meteorites, containing up to 3.5 weight percent of carbon) and is the first ever meteorite of this type to be found in the U.K. with an observed meteorite fall event, with more than 1,000 eyewitnesses and numerous footages of the fireball. The amino acid abundance of Winchcombe is ten times lower than other types of carbonaceous chondritic meteorites and was a challenge to study due to the limited detection of amino acids, but with the meteorite so promptly recovered and curated, the team were able to study the organic content of the meteorite prior to its interaction with the Earth's environment. The organic matter suggests the meteorite could represent a class of unique, weak meteorite not previously studied.

Winchcombe belongs to a rare type of carbonaceous meteorite which typically contains a rich inventory of organic compounds and water. The first Winchcombe meteorite stone was recovered within 12 hours of the fireball observation event and properly curated to restrict any terrestrial contamination. This allowed the researchers to study the organic signature truly essential to the meteorite itself.

Studying the organic inventory of the Winchcombe meteorite provided scientists with a window into the past, how simple chemistry kick started the origin of life at the birth of our solar system. Discovering these life's precursor organic molecules allowed them to comprehend the fall of similar material to the surface of the Earth, prior to the emergence of life on our own planet.

Queenie H. S. Chan et al, The amino acid and polycyclic aromatic hydrocarbon compositions of the promptly recovered CM2 Winchcombe carbonaceous chondrite, Meteoritics & Planetary Science (2023). DOI: 10.1111/maps.13936

Comment by Dr. Krishna Kumari Challa on January 15, 2023 at 2:48pm

Mucus-Eating Gut Bacteria May Promote Fever After Cancer Treatment

The expansion of mucus-degraders in the mouse gut—possibly due to poor nutrition—thins the colon’s mucus layer and may weaken defenses against blood-infecting microbes.

One of the most common consequences of cytotoxic cancer treatments, such as chemotherapy and radiation, is the loss of a type of white blood cell called neutrophils—a phenomenon known as neutropenia. In some severe cases of neutropenia, patients develop a fever. Research published November 16 in Science Translational Medicine links this fever to mucus-degrading bacteria in the gut, specifically the commensal Akkermansia muciniphila. The study authors show that these microbes thin the mucus layer in mice, potentially exposing hosts to further bacterial infections—a finding that hints at possible ways to stave off treatment-related fevers in humans.

https://www.science.org/doi/10.1126/scitranslmed.abo3445

Comment by Dr. Krishna Kumari Challa on January 15, 2023 at 2:38pm

Humans Are Still Evolving Thanks to Microgenes

A study sheds light on the tiny genes that have evolved in human genomes since we split from our mammalian ancestors.

ABOVE:© ISTOCK.COM, MEVANS

Humans are still evolving new genes, according to a study published in Cell Reports on December 20. As our lineage evolved, at least 155 human genes sprung up from DNA regions previously thought of as “junk,” including two human-specific genes that emerged since humans branched off from chimpanzees around 4 to 6 million years ago, the researchers report.

The genes described in the new study went undiscovered for so long because they’re teeny: They top out at about 300 nucleotides in length, while a typical human gene is 10 to 15,000 base pairs on average. Even though they possess start and stop codons that allow them to be read by cells’ transcriptional machinery just like traditional genes, these so-called microgenes—sometimes called short open reading frames (sORFs)—have long been assumed to be nonfunctional.

But recent studies found that knocking out sORFs stunts cell growth, indicating they’re important after all. One 2020 study, for example, found hundreds of functional sORFs in human cells, both in the coding and noncoding regions of the genome. The number was intriguing to evolutionary biologists and they were compelled to investigate these genetic oddities further, launching what became the newly published research. “We find species-specific genes everywhere,” the researchers say. “So there has to be an evolutionary route for them to originate.”

Using data from the 2020 study, the team scanned human and vertebrate genomes for functional sORFs that produced proteins. Then, using known human and vertebrate phylogenetic information, they predicted the evolutionary relationships among the sORFs estimated when in evolutionary history new microgenes had come about.

Through this process, the team identified 155 microgenes that all vertebrates share. Forty-four of these are critical for cell growth, according to data from the previous study. Three have disease markers associated with ailments such as muscular dystrophy, retinitis pigmentosa, and Alazami syndrome. The team also found one microgene—associated with human heart tissue—that cropped up after chimps and humans split off from gorillas about 7 to 9 million years ago.

The researchers found that these new genes had emerged from the noncoding regions of DNA, rather than by mutation or duplication of existing genes. While gene duplication is thought to be the main source of new genes in all species, the appearance of microgenes might explain how humans developed some uniquely human characteristics, as well as how other animals gained uniquely species-specific phenotypes.

https://www.cell.com/cell-reports/fulltext/S2211-1247(22)01696-5?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2211124722016965%3Fshowall%3Dtrue

Comment by Dr. Krishna Kumari Challa on January 15, 2023 at 2:21pm

How Rocky Planets Form

Comment by Dr. Krishna Kumari Challa on January 15, 2023 at 1:26pm

Blue light might be bad for humans - but good for mangoes

 We’re often told to limit our “screen time,” thanks in part to the harsh blue light that screens can emit. Plants can detect blue light too, but instead of causing sleepless nights for our green friends, it could help make their fruits taste better. Researchers now report in ACS’ Journal of Agricultural and Food Chemistry that mangoes can become redder, sweeter and more ripe when exposed to blue light over several days.

Plants rely on sunlight to carry out photosynthesis and ripen their fruits. Studies have shown that exposure to light can affect the appearance of some fruits’ peels and can increase the amount of sugar and pigments in fruits such as tomatoes, which contain chlorophyll throughout their flesh. However, other fruits such as mangoes only contain this pigment in their thick peels, which could change how light affects the flesh. Plus, sunlight contains many colors, so different wavelengths could have different effects. So, researchers wanted to investigate how blue light impacts the quality and ripeness of mangoes.

To understand this phenomenon, the researchers placed a group of mangoes in blue light and another group in darkness for nine days. They found that mangoes in blue light contained far more anthocyanins in their peels, making them redder than those left in the dark. The flesh of these mangoes was also softer, sweeter and more yellow, and had more sucrose and carotenoids than the other group. In further tests, the team found that light-responsive genes involved in the photosynthesis pathway, as well as key genes involved in producing sucrose, anthocyanin and carotenoids, were upregulated under blue light. This meant that the mangoes could directly perceive this light and trigger an internal genetic signaling pathway, say the researchers. The effect was more pronounced in the peel than in the flesh, indicating that the blue light did not penetrate much past the skin. The researchers say that this work could help shed light on the complex relationship behind colored light and the internal quality of fruit.

https://www.acs.org/pressroom/presspacs/2022/acs-presspac-december-....

https://pubs.acs.org/doi/abs/10.1021/acs.jafc.2c07137

Comment by Dr. Krishna Kumari Challa on January 15, 2023 at 1:20pm

Novel lipstick formula could offer protection against a variety of disease-causing microorganisms.

Lipstick can be a confidence booster, enhance a costume and keep lips from chapping. But sharing a tube with a friend or family member can also spread infections. To develop a version with antimicrobial properties, researchers reporting in ACS Applied Materials & Interfaces have added cranberry extract to the formulation. Their deep red cream quickly inactivates disease-causing viruses, bacteria and a fungus that come in contact with it.

According to historians, people in ancient Egypt were the first to use make-up, applying pastes made from minerals and other substances in their environment. The formulations have evolved over the centuries, but now researchers have come full circle, looking again toward natural ingredients. For example, recent studies have reported that lipstick formulas incorporating natural colorants, such as red dragon fruit, can result in products with both vibrant colors and antimicrobial activity. And previously, cranberry extract has been shown to inactivate viruses, bacteria and fungi. So, researchers wanted to use cranberry extract to create a deep red lip tint with antimicrobial properties.

They mixed cranberry extract into a lipstick cream base, which contained shea butter, vitamin E, provitamin B5, babassu oil and avocado oil. In experiments, the reddened cream was added to cultures containing different viruses, bacteria and one fungal species. Both enveloped and non-enveloped virus types were completely inactivated within a minute of contact with the cranberry-containing cream. And the multidrug-resistant bacteria, mycobacteria and fungus were substantially inactivated within five hours of applying the cream. The researchers suggest that their novel lipstick formula could offer protection against a variety of disease-causing microorganisms.

https://www.acs.org/pressroom/presspacs/2022/acs-presspac-december-...

https://pubs.acs.org/doi/abs/10.1021/acsami.2c19460

Comment by Dr. Krishna Kumari Challa on January 14, 2023 at 9:49am

Migrating birds: Disturbances in magnetic field suspected when bird...

It seems logical enough that bad weather can sometimes cause birds to become disoriented during their annual fall migrations—causing them to wind up in territory they're unaccustomed to. But why, even when weather is not a major factor, do birds travel far away from their usual routes?

Comment by Dr. Krishna Kumari Challa on January 14, 2023 at 9:48am

Raman spectroscopy method for rapid identification of beer spoilage bacteria

In a study published in Analytical Methods, a research group proposed the rapid detection of beer spoilage bacteria based on label-free surface-enhanced Raman spectroscopy (SERS) technology.

Lactic acid bacteria are common spoilage bacteria in beer and need to be monitored and controlled at all stages of beer production. Traditional spoilage bacteria detection methods are time-consuming and cannot meet the demand for real-time, in-situ, rapid detection during the production process.

Raman spectroscopy has been widely used for microbial detection due to its fast, non-destructive and accurate properties, but conventional Raman spectroscopy has the disadvantage of poor signal-to-noise ratio, which affects the accuracy of microbial identification.

Compared with conventional Raman spectroscopy, the SERS technique has a stronger and more sensitive signal and is well suited to the detection of beer spoilage bacteria. Furthermore, the label-free SERS technique is ideal for commercialization due to its low cost and good results.

In this study, the researchers improved the existing process for the preparation of label-free SERS silver nanoparticles (AgNPs). The effect of the AgNPs@KCl agglomeration effect on SERS enhancement was investigated. Eight species of beer spoilage bacteria produced during the beer brewing process were identified by SERS.

The researchers further investigated the effect of the method on the final identification rate by combining the t-distributed stochastic neighbor embedding (t-SNE) dimensionality reduction analysis algorithm, Support Vector Machine (SVM), k-NearestNeighbor (KNN) and Linear Discriminant Analysis (LDA) machine learning algorithms. All three machine learning algorithms achieved an accuracy of around 90% and performed well in identifying beer spoilage bacteria.

In the stability analysis and mixing tests, two known spoilage bacteria were mixed with pure beer and incubated at constant temperature for a period of time to identify the bacteria in the beer. The two spoilage bacteria were successfully detected in the samples and had good spectral stability.

According to the final validation study, the technique can indeed identify the target spoilage bacteria from the simulated samples, which is of great significance to the rapid identification of spoilage bacteria in the beer brewing process.

Lindong Shang et al, Rapid detection of beer spoilage bacteria based on label-free SERS technology, Analytical Methods (2022). DOI: 10.1039/D2AY01221A

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