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Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 8:51am

Study of older patients suggests 1 in 5 cases of dementia may be attributable to vision impairment

Prior research has found that there may be a connection between hearing loss in aging people and the onset of dementia. In a new study, a team of health care researchers and geriatric specialists  surveyed patient health care records and reported that approximately 1 in 5 cases of dementia could also be attributable to vision impairment in community-dwelling  adults aged 71 years or older.

The paper is published in the journal JAMA Ophthalmology.

Scientists still do not know what causes dementia, but they strongly suspect that it might be tied to several factors, one of which might be sensory degradation. As the senses lose their sharpness, the hypothesis proposes, the brain must work harder to make sense of the external environment, all while undergoing its own aging process.

The result could be loss of cognitive and memory abilities. In this new effort, the researchers looked for such evidence in people over the age of 71 who have experienced at least one of three main types of vision impairment: near or distance acuity, or contrast sensitivity.

They found that approximately 19% of dementia cases could be attributable to one or more types of vision loss. This, they note, suggests that dementia could have been prevented in nearly 20% of cases if loss of vision had been addressed. They note that prior studies have shown that approximately 90% of vision problems in older people are correctable through glasses or surgery.

The research team acknowledges that their results are based on associations rather than proof because there is no way to prove any single cause of dementia. But they also suggest that the associations they found make a strong case for it.

More information: Jason R. Smith et al, Vision Impairment and the Population Attributable Fraction of Dementia in Older Adults, JAMA Ophthalmology (2024). DOI: 10.1001/jamaophthalmol.2024.3131

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Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 8:27am

Researchers discover an effective and environment-friendly disinfectant

A widely used disinfectant worldwide, chloroxylenol, has been associated with eco-toxicological threats in water environments due to its relatively high chemical stability and massive consumption. Researchers at the School of Engineering of the Hong Kong University of Science and Technology (HKUST) have discovered a promising alternative known as 2,6-dichlorobenzoquinone (2,6-DCQ), which works more effectively in combating certain common bacteria, fungi and viruses, and can be rapidly degraded and detoxified in receiving waters.

Their findings have been published in Nature Communications.

Jiarui Han et al, An effective and rapidly degradable disinfectant from disinfection byproducts, Nature Communications (2024). DOI: 10.1038/s41467-024-48752-w

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 8:14am

Among the planets in the solar system, Earth is unique for having plate tectonics. Its rocky surface is split into fragments (plates) that grind into each other and create mountains, or split away and form chasms that are then filled with oceans.

Apart from causing earthquakes and volcanoes, plate tectonics also pushes up rocks from the deep earth into the heights of mountain ranges. This way, elements which were far underground can erode from the rocks and end up washing into rivers and oceans. From there, living things can make use of these elements.

Among these essential elements is phosphorus, which forms the framework of DNA molecules, and molybdenum, which is used by organisms to strip nitrogen out of the atmosphere and make proteins and amino acids—building blocks of life.

Plate tectonics also exposes rocks that react with carbon dioxide in the atmosphere. Rocks locking up carbon dioxide is the main control on Earth's climate over long time scales—much, much longer than the tumultuous climate change we are responsible for today.

Mapping the past plate tectonics of the planet is the first stage in being able to build a complete digital model of Earth through its history.

Xianzhi Cao et al, Earth's tectonic and plate boundary evolution over 1.8 billion years, Geoscience Frontiers (2024). DOI: 10.1016/j.gsf.2024.101922

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 8:13am

1.8 Billion Years of Plate Tectonics

Using information from inside the rocks on Earth's surface, researchers have reconstructed the plate tectonics of the planet over the last 1.8 billion years.

It is the first time Earth's geological record has been used like this, looking so far back in time. This has enabled us to make an attempt at mapping the planet over the last 40% of its history, which you can see in the animation below.

The work is now published in the open-access journal Geoscience Frontiers.

Mapping our planet through its long history creates a beautiful continental dance—mesmerizing in itself and a work of natural art.

It starts with the map of the world familiar to everyone. Then India rapidly moves south, followed by parts of Southeast Asia as the past continent of Gondwana forms in the Southern Hemisphere.

Around 200 million years ago (Ma or mega-annum in the reconstruction), when the dinosaurs walked the earth, Gondwana linked with North America, Europe and northern Asia to form a large supercontinent called Pangea.

Then, the reconstruction carries on back through time. Pangea and Gondwana were themselves formed from older plate collisions. As time rolls back, an earlier supercontinent called Rodinia appears. It doesn't stop here. Rodinia, in turn, is formed by the break-up of an even older supercontinent called Nuna about 1.35 billion years ago.

Part 1

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 8:07am

Researchers make sound waves travel in one direction only, with implications for electromagnetic wave technology

Researchers at ETH Zurich have managed to make sound waves travel only in one direction. In the future, this method could also be used in technical applications with electromagnetic waves.

Water, light and sound waves usually propagate in the same way forward as in a backward direction. As a consequence, when we are speaking to someone standing some distance away from us, that person can hear us as well as we can hear them. This is useful when having a conversation, but in some technical applications one would prefer the waves to be able to travel only in one direction—for instance, in order to avoid unwanted reflections of light or microwaves.

Ten years ago, researchers succeeded in suppressing sound wave propagation in the backward direction; however, this also attenuated the waves traveling forwards.

A team of researchers has now developed a method for preventing sound waves from traveling backward without deteriorating their propagation in the forward direction.

The basis of this one-way street for sound waves are self-oscillations, in which a dynamical system periodically repeats its behavior.

In the future, this method, which has recently been published in Nature Communications, could also be applied to electromagnetic waves.

Tiemo Pedergnana et al, Loss-compensated non-reciprocal scattering based on synchronization, Nature Communications (2024). DOI: 10.1038/s41467-024-51373-y

Part 2

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 7:58am

Low-cost nanomaterial technology can detect cancer genes with ultra-high sensitivity

A research team has  developed a technology that can detect cancer mutant genes in blood with the world's highest sensitivity of 0.000000001% based on plasmonic nanomaterials for optical signal amplification. The team tested blood samples from lung cancer patients (stages 1-4) and healthy individuals for EGFR mutations and achieved a diagnostic accuracy of 96%.

The work is published in the journal Small Science.

Previously utilized genetic analysis technologies had low analytical sensitivity to detect mutated genes compared to normal genes, making it difficult to accurately diagnose early-stage cancer patients. In addition, it was difficult to establish a quick treatment strategy and apply it to screening tests due to the high cost and long time required for analysis and the need for special equipment.

To overcome these challenges, the research team developed a low-cost analysis technology that can analyze various cancer mutations within the target gene region within one hour with an ultra-high sensitivity of 0.000000001%. This technology boasts the world's highest level of sensitivity, which is 100,000 times better than the highest level of 0.0001% among reported technologies, and through this, the possibility of early diagnosis was confirmed using the blood of lung cancer patients.

This technology combines nanomaterial technology that significantly improves the fluorescence signal, and primer/probe design that suppresses the fluorescence signal of normal genes, amplifying only the fluorescence signal of cancer mutant genes. This is because the accurate detection of even very small amounts of cancer mutated genes requires not only strong fluorescent signal expression technology but also precise discrimination of fine fluorescent signals.

The team fabricated a biochip in the form of a microarray capable of simultaneously detecting three mutant genes of EGFR (deletion, insertion, and point mutations) on a plasmonic substrate made of three-dimensional, high-density gold nanostructures. After evaluating the clinical performance of 43 domestic lung cancer patients (stages 1 to 4) and 40 normal groups, a clinical sensitivity of 93% for lung cancer patients and a clinical specificity of 100% for the normal group were confirmed.

This technology can play an important role in not only early diagnosis and detection of recurrence of cancer, but also in monitoring treatment effectiveness and establishing personalized treatment plans. In addition, liquid biopsy using blood is possible as an alternative to surgical tissue biopsy, reducing the burden on patients and simplifying the examination process. It can also serve as a regular screening test, ultimately improving the quality of cancer management and treatment.

Ji Young Lee et al, Highly Sensitive 3D‐Nanoplasmonic‐Based Epidermal Growth Factor Receptor Mutation Multiplex Assay Chip for Liquid Biopsy, Small Science (2024). DOI: 10.1002/smsc.202400101

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 7:17am

Tiny magnetic robots could treat bleeds in the brain

Researchers have created nanoscale robots which could be used to manage bleeds in the brain caused by aneurysms. The development could enable precise, relatively low-risk treatment of brain aneurysms, which cause around 500,000 deaths globally each year. The medical condition—a blood-filled bulge on a brain artery that can rupture and cause fatal bleeds—can also lead to stroke and disability.

The study points to a future where tiny robots could be remotely controlled to carry out complex tasks inside the human body—such as targeted drug delivery and organ repair—in a minimally invasive way, researchers say.

The researchers engineered magnetic nanorobots—about a twentieth the size of a human red blood cell—comprising blood-clotting drugs encased in a protective coating, designed to melt at precise temperatures. The work is published in the journal Small.

In lab tests, several hundred billion such bots were injected into an artery and then remotely guided as a swarm, using magnets and medical imaging, to the site of an aneurysm.

Magnetic sources outside the body then cause the robots to cluster together inside the aneurysm and be heated to their melting point, releasing a naturally occurring blood-clotting protein, which blocks the aneurysm to prevent or stem bleeding into the brain.

The international team of researchers successfully tested their devices in model aneurysms in the lab and in a small number of rabbits.

The team says that nanorobots show potential for transporting and releasing drug molecules to precise locations in the body without risk of leaking into the bloodstream—a key test of the technology's safety and efficacy.

The study could pave the way for further developments towards trials in people.

Jienan Wang et al, Nanoarchitectonic Engineering of Thermal‐Responsive Magnetic Nanorobot Collectives for Intracranial Aneurysm Therapy, Small (2024). DOI: 10.1002/smll.202400408

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 7:12am

AI helps distinguish dark matter from cosmic noise

Dark matter is the invisible force holding the universe together—or so we think. It makes up about 85% of all matter and around 27% of the universe's contents, but since we can't see it directly, we have to study its gravitational effects on galaxies and other cosmic structures. Despite decades of research, the true nature of dark matter remains one of science's most elusive questions.

According to a leading theory, dark matter might be a type of particle that barely interacts with anything else, except through gravity. But some scientists think these particles could occasionally interact with each other, a phenomenon known as self-interaction. Detecting such interactions would offer crucial clues about dark matter's properties.

However, distinguishing the subtle signs of dark matter self-interactions from other cosmic effects, like those caused by active galactic nuclei (AGN)—the supermassive black holes at the centers of galaxies—has been a major challenge. AGN feedback can push matter around in ways that are similar to the effects of dark matter, making it difficult to tell the two apart.

In a significant step forward, astronomers   have developed a deep-learning algorithm that can untangle these complex signals. The research is published in Nature Astronomy.

Their AI-based method is designed to differentiate between the effects of dark matter self-interactions and those of AGN feedback by analyzing images of galaxy clusters—vast collections of galaxies bound together by gravity. The innovation promises to greatly enhance the precision of dark matter studies.

A deep-learning algorithm to disentangle self-interacting dark matter and AGN feedback models, Nature Astronomy (2024). DOI: 10.1038/s41550-024-02322-8

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 7:02am

Hijacking the command center of the cell: Nuclear parasites

Most animals live in intimate relationships with bacteria. Some of these bacteria live inside the cells of their hosts, but only very few are able to live inside cell organelles (structures inside the cell, like organs in the body). One group of bacteria have figured out how to colonize the nuclei of their hosts, a remarkable feat given that the nucleus is the control center of the cell.

To date, nothing is known about the molecular and cellular processes that these intranuclear bacteria use to infect and reproduce in animal hosts. A group of scientists now presents the first in-depth analysis of an intranuclear parasite of animals in a study published in Nature Microbiology.

This intranuclear parasite, Candidatus endonucleobacter, infects the nuclei of deep-sea mussels from hydrothermal vents and cold seeps around the world. A single bacterial cell penetrates into the mussels' nucleus and then reproduces to over 80,000 cells, causing the nucleus to swell to 50 times its original size.

Using a suite of molecular and imaging methods, the scientists revealed that Ca. endonucleobacter lives on sugars, lipids and other cell components from its host. It does not digest its host nucleic acids, like many other intranuclear bacteria. This feeding strategy ensures that the host cell functions long enough to provide Ca. endonucleobacter with the nutrients it needs to reproduce in such massive numbers.

A common response of animal cells to infection is apoptosis—a suicide program that cells initiate when they are damaged or infected by bacteria or viruses.

Interestingly, these bacteria have come up with a sophisticated strategy to keep their host cells from killing themselves. They produce proteins that suppress apoptosis called inhibitors of apoptosis (IAPs).

An arms race for the control of cell death then ensues: As the bacteria produce more and more IAPs, the host cell ramps up its production of proteins that induce apoptosis. Eventually, after the parasite has had enough time to multiply in masses, the host cell ruptures, releasing the bacteria and allowing them to infect new host cells.

This discovery expands our understanding of host-microbe interactions and highlights the complex strategies parasites have evolved to thrive in their hosts.

These findings could have broader implications for studying parasitic infections and immune evasion strategies in other organisms.

 An intranuclear bacterial parasite of deep-sea mussels expresses apoptosis inhibitors acquired from its host, Nature Microbiology (2024). DOI: 10.1038/s41564-024-01808-5

Comment by Dr. Krishna Kumari Challa on September 7, 2024 at 6:54am

Excessive light pollution may increase risk of Alzheimer's, especially in younger people

In some places around the globe, the lights never go off. Streetlights, roadway lighting, and illuminated signs can deter crime, make roads safer, and enhance landscaping. Undisrupted light, however, comes with ecological, behavioral, and health consequences. 

Researchers now  have investigated correlations between outside nightly light pollution and Alzheimer's disease (AD).

There is a positive association between AD prevalence and exposure to light at night, particularly in those under the age of 65, the researchers showed. Nightly light pollution—a modifiable environmental factor—may be an important risk factor for AD, they say.

The researchers studied light pollution maps of the lower 48 US states and incorporated medical data about variables known or believed to be risk factors for AD in their analysis. They generated nighttime intensity data for every state and divided them into five groups, from lowest to highest nighttime light intensity.
Their results showed that for people aged 65 and older, AD prevalence was more strongly correlated with nightly light pollution than some other disease factors, including alcohol abuse, chronic kidney disease, depression, and obesity. Other risk factors, like diabetes, high blood pressure, and stroke were more strongly associated with AD than light pollution.
For people aged under 65, however, the researchers found that higher nighttime light intensity was associated with a greater AD prevalence than any other risk factor examined in the study. This could suggest that younger people may be particularly sensitive to the effects of light exposure at night, the researchers said.

It is unclear why younger people could be more vulnerable, but it could be due to individual differences in light sensitivity. Certain genotypes, which influence early-onset AD, impact the response to biological stressors which could account for increased vulnerability to the effects of nighttime light exposure. Additionally, younger people are more likely to live in urban areas and have lifestyles that may increase exposure to light at night.

The researchers hope that their findings can help educate people about the potential risks of light at night.

Robin M. Voigt et all, Outdoor Nighttime Light Exposure (Light Pollution) is Associated with Alzheimer's Disease, Frontiers in Neuroscience (2024). DOI: 10.3389/fnins.2024.1378498

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