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Comment by Dr. Krishna Kumari Challa on December 6, 2023 at 1:59pm

Replacing bone saws with smart lasers

Even back in 1957, when Gordon Gould coined the term "laser" (short for "Light Amplification by Stimulated Emission of Radiation"), he was already imagining the possibilities for its use in medicine. Surgeons would be able to make precise incisions without even touching the patient.

Before that could happen, however, there were—and still are—many hurdles to overcome. Manually controlled light sources have been superseded by mechanical and computer-controlled systems to reduce injuries caused by clumsy handling. Switching from continuous beams to pulsed lasers, which turn themselves rapidly on and off, has reduced the heat they produce. Technical advances allowed lasers to enter the world of ophthalmology in the early 1990s. Since then, the technology has moved on in other areas of medicine, too, but only in relatively few applications has it replaced the scalpel and the bone saw.

Safety concerns are the most important hurdle: how can we prevent injury to the surrounding tissue? How closely can the cutting depth be controlled so that deeper layers of tissue are not accidentally damaged?

Researchers  have just made an important contribution to the safe and precise use of lasers with their recent publication in the journal Lasers in Surgery and Medicine. They  developed a system that combines three functions: it cuts bone, controls the cutting depth and differentiates between different tissues.

These three functions are carried out by three lasers that are aligned to focus on the same spot. The first laser serves as a tissue sensor in that it scans the surroundings of the site where the bone is to be cut.

Pulses are sent with this laser to the surface at regular intervals, so to speak, vaporizing a tiny bit of tissue each time. The composition of this vaporized tissue is measured with a spectrometer. Each type of tissue has its own individual spectrum—its own signature. An algorithm processes this data and creates a kind of map that shows where the bones are located and where the soft tissue is.

Not until all of this has been completed does the second laser, which cuts bone, activate, and then only in places where bones rather than soft tissue are shown on the map that has just been generated. At the same time, the third laser—an optical system—measures the depth of the cut and checks that the cutting laser is not penetrating more deeply than planned. During the cutting phase, the tissue sensor also constantly monitors whether the correct tissue is being cut.

The special thing about this system is that it controls itself—without human interference.

The researchers have so far been testing their system on femur bones and tissue from pigs acquired from a local butcher. They were able to prove that their system works accurately down to fractions of a millimeter. The speed of the combined laser also approaches that of a conventional surgical procedure.

The research team is currently working on making the system smaller.

Arsham Hamidi et al, Multimodal feedback systems for smart laser osteotomy: Depth control and tissue differentiation, Lasers in Surgery and Medicine (2023). DOI: 10.1002/lsm.23732 Arsham Hamidi et al,

Towards miniaturized OCT-guided laser osteotomy: integration of fiber-coupled Er:YAG laser with OCT, Optics Continuum (2023). DOI: 10.1364/OPTCON.497483

Comment by Dr. Krishna Kumari Challa on December 6, 2023 at 1:21pm

Harvesting water from air with solar power

More than 2.2 billion people currently live in water-stressed countries, and the United Nations estimates that 3.5 million die every year from water-related diseases. Because the areas most in need of improved drinking water are also located in some of the sunniest places in the world, there is strong interest in harnessing sunlight to help obtain clean water.

Researchers  developed a promising new solar-powered atmospheric water harvesting technology that could help provide enough drinking water for people to survive in those difficult, dryland areas.

Historically, researchers have faced challenges when injecting salt into hydrogels as the higher salt content reduced the swelling capacity of the hydrogel due to the salting-out effect. This led to salt leakage and the water absorption capacity decreased.

The researchers synthesized a super hygroscopic gel using plant derivatives and hygroscopic salts that was capable of absorbing and retaining an unparalleled amount of water. One kilogram of dry gel could adsorb 1.18 kilograms of water in arid atmospheric environments and up to 6.4 kilograms in humid atmospheric environments. This hygroscopic gel was simple and inexpensive to prepare and would consequently be suitable for large-scale preparation.

In addition, the team adopted a prototype with desorption and condensation chambers, configured in parallel. They employed a turbofan in the condensation chamber to increase the recovery of desorbed water to more than 90%.

In an outdoor prototype demonstration, the team found it released adsorbed water even in the morning or afternoon when the sun is weak. The system could also achieve simultaneous adsorption and desorption during the daytime.

The team is trying to work to achieve simultaneous adsorption and desorption using renewable energy  to maximize daily water yield per unit mass of adsorbent to further optimize the system's performance for practical applications in water generation.

Chengjie Xiang et al, Daytime air-water harvesting based on super hygroscopic porous gels with simultaneous adsorption-desorption, Applied Physics Reviews (2023). DOI: 10.1063/5.0160682

Comment by Dr. Krishna Kumari Challa on December 6, 2023 at 1:16pm

Eye scans can provide crucial insights into kidney health, study finds

3D eye scans can reveal vital clues about kidney health that could help to track the progression of disease, research suggests. The advance could revolutionize the monitoring of kidney disease, which often progresses without symptoms in the early stages.

Experts say the technology has the potential to support early diagnosis as current screening tests cannot detect the condition until half of the kidney function has been lost. Researchers used highly magnified images to detect changes to the retina—the layer of tissue at the back of the eye that senses light and sends signals to the brain. They found that the images offer a quick, non-invasive way to monitor kidney health.

The eye is the only part of the body where it is possible to view a key process called microvascular circulation—and this flow of blood through the body's tiniest vessels is often affected in kidney disease.

 investigated whether 3D images of the retina, taken using a technology called optical coherence tomography (OCT), could be used to identify and accurately predict the progression of kidney disease.

OCT scanners—used in most high street opticians—use  light waves to create a cross-sectional picture of the retina, displaying each individual layer, within a few minutes.

The team looked at OCT images from 204 patients at different stages of kidney disease, including transplant patients  alongside 86 healthy volunteers. They found that patients with chronic kidney disease had thinner retinas compared with healthy volunteers. The study also showed that thinning of the retina progressed as kidney function declined.

These changes were reversed when kidney function was restored following a successful transplant. Patients with the most severe form of the disease, who received a kidney transplant, experienced rapid thickening of their retinas after surgery.

This knowledge can be utilized in the future to identify the kidney ailments fast.

 Neeraj Dhaun et al, Choroidal & retinal thinning in chronic kidney disease are modifiable with treatment & independently associate with eGFR decline, Nature Communications (2023). www.nature.com/articles/s41467-023-43125-1

Comment by Dr. Krishna Kumari Challa on December 5, 2023 at 7:05am

Cracked Piece of Metal Heals Itself in Experiment 

Scientists observed a metal healing itself, something never seen before. If this process can be fully understood and controlled, we could be at the start of a whole new era of engineering.

In a study published in July, a research team  was testing the resilience of the metal, using a specialized transmission electron microscope technique to pull the ends of the metal 200 times every second. They then observed the self-healing at ultra-small scales in a 40-nanometer-thick piece of platinum suspended in a vacuum. Cracks caused by the kind of strain described above are known as fatigue damage: repeated stress and motion that causes microscopic breaks, eventually causing machines or structures to break. Amazingly, after about 40 minutes of observation, the crack in the platinum started to fuse back together and mend itself before starting again in a different direction.

https://www.nature.com/articles/s41586-023-06223-0

Comment by Dr. Krishna Kumari Challa on December 5, 2023 at 7:01am

Researchers extracted and sequenced DNA from inside the clay of an ancient brick found in modern-day Iraq. They found genetic material from 34 taxonomic groups, including cabbage, heather, birch and cultivated grasses, in sun-dried bricks used to construct a palace in Mesopotamia (now part of Iraq) nearly 3,000 years ago.

Why this is so cool: Although scientists have previously extracted ancient DNA, or aDNA, from bones and lake sediments, they hadn't used existing techniques on clay bricks because the brick-baking process usually destroys biological material. The team also accurately dated this particular brick to within several decades (883–859 B.C.E.), thanks to an inscription on its side: “The property of the palace of Ashurnasirpal, king of Assyria.” The brick also listed the king in genealogical order, so the researchers could cross-check that against a list of known rulers from the time.

What the experts say: Archaeobotanists currently examine evidence of ancient plant life by using chemical processes or imaging microscopes; extracting aDNA “could potentially be a valuable addition,” say, an archaeobotanist.

Comment by Dr. Krishna Kumari Challa on December 5, 2023 at 6:55am

Toxic chemicals in  whales and dolphins are exceeding safe limits

Almost half of marine mammals around the UK are being poisoned by banned chemicals.

The compounds, once used in pesticides, flame retardants and coolants, are having significant impacts on the health and reproduction of the animals.

The UK's whales and dolphins are full of toxins—and it might only get worse.

Despite many being banned almost 20 years ago, levels of persistent organic pollutants (POPs) remain high in the oceans. In fact, these chemicals may breach safe limits in as many as half of all marine mammals living around the UK, based on a new study of stranded animals.

While the researchers found that levels of six key POPs are declining, they're concerned that the chemicals currently contained in coastal landfill sites could increasingly leak out as flooding, extreme weather and coastal erosion are enhanced by climate change.

What is alarming is this can happen anywhere in the world.

Rosie S. Williams et al, Spatiotemporal Trends Spanning Three Decades Show Toxic Levels of Chemical Contaminants in Marine Mammals, Environmental Science & Technology (2023). DOI: 10.1021/acs.est.3c01881

Comment by Dr. Krishna Kumari Challa on December 5, 2023 at 6:47am

Brain implants revive cognitive abilities long after traumatic brain injury in clinical trial

A lady in her final semester of college, planning to apply to law school, when she suffered a traumatic brain injury in a car accident. The injury so compromised her ability to focus she struggled in a job sorting mail.

She couldn't remember anything . Her left foot dropped, so she'd trip over things all the time. She was always in car accidents. And she had no filter—she'd get pissed off really easily.

Her parents learned about research being conducted at Stanford Medicine and reached out; she was accepted as a participant. In 2018, physicians surgically implanted a device deep inside her brain, then carefully calibrated the device's electrical activity to stimulate the networks the injury had subdued. The results of the clinical trial were published Dec. 4 in Nature Medicine. She noticed the difference immediately. When she was asked to list items in the produce aisle of a grocery store, she could rattle off fruits and vegetables. Then a researcher turned the device off, and she couldn't name any. Since the implant she hadn't  had any speeding tickets she said. She doesn't trip anymore. She can remember how much money is in her bank account. She  wasn't able to read earlier, but after the implant she bought a book, 'Where the Crawdads Sing,' and loved it and remembered it. And she doesn't have that quick temper." For her and four others, the experimental deep-brain-stimulation device restored, to different degrees, the cognitive abilities they had lost to brain injuries years before. The new technique, developed by Stanford Medicine researchers and collaborators from other institutions, is the first to show promise against the long-lasting impairments from moderate to severe traumatic brain injuries.

Nicholas Schiff, Thalamic deep brain stimulation in traumatic brain injury: a phase 1, randomized feasibility study, Nature Medicine (2023). DOI: 10.1038/s41591-023-02638-4. www.nature.com/articles/s41591-023-02638-4

Comment by Dr. Krishna Kumari Challa on December 4, 2023 at 7:05am

The brain sizes of our ancestors, the Australopiths, were similar to those of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). The human lineage's brain expansion accelerated with Homo's emergence and continued through Homo sapiens and Homo neanderthalensis.

How did our ancestors, with brains about the size of chimpanzees, manage to harness the power of external fermentation?

Researchers suggest that hominids with lower cognitive abilities and smaller brains may have adapted to fermentation much earlier than proposed alternative alternative explanations for this gut-to-brain energy redirection, like animal hunting and fire-based cooking.
Fermentation has many advantages associated with cooked foods, such as softer textures, increased caloric content, improved nutrient absorption, and defense against harmful microorganisms.
The researchers emphasize the need for empirical research to support or refute their hypothesis, such as microbiological studies, comparative analyses, and genetic and genomic investigations.

https://www.nature.com/articles/s42003-023-05517-3

Part 2

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Comment by Dr. Krishna Kumari Challa on December 4, 2023 at 7:02am

Food Preserving Technique May Have Sparked Human Brain Growth: Researchers

Researchers propose that a taste for fermented morsels may have triggered a surprising jump in the growth rate of our ancestors' brains.

In fact, a shift from a raw diet to one that included food items already partially broken down by microbes may have been a crucial event in our brain's evolution, according to a perspective study by evolutionary neuroscientists.

Human brains have tripled in size over the last two million years of evolution, while human colons have shrunk by an estimated 74 percent, suggesting a reduced need to break down plant-derived food internally.
We know the timeline and extent of human brain expansion, but the mechanisms allowing energy to be directed to this expansion are more complex and somewhat debated.

The study authors lay out their "external fermentation hypothesis" which shows our ancestors' metabolic circumstances for selective brain expansion may have been set in motion by moving intestinal fermentation to an external process, perhaps even experimenting with preserved foods not unlike the wine, kimchi, yoghurt, sauerkraut, and other pickles we still eat today.
The human gut microbiome acts like a machine for internal fermentation, which boosts nutrient absorption during digestion. Organic compounds are fermented into alcohol and acids by enzymes, usually produced by the bacteria and yeasts that live in parts of our digestive system such as our colon.
Fermentation is an anaerobic process, meaning it doesn't require oxygen, so similar to the process in our guts, it can occur in a sealed container. The process produces energy in the form of adenosine triphosphate (ATP), which is an essential source of chemical energy that powers our metabolism.

The researchers argue it's possible that culturally passed-down ways of handling or storing food encouraged this function to be externalized.

Externally fermented foods are easier to digest and contain more available nutrients than their raw equivalents. And since there's less for the colon to do if the food is already fermented, the organ's size could reduce over time while still potentially leaving energy available for brain growth.
Part 1

Comment by Dr. Krishna Kumari Challa on December 3, 2023 at 2:34pm

Dolphins can detect electrical fields

Two captive bottlenose dolphins (Tursiops truncatus) have now proved to researchers at the University of Rostock and Nuremberg Zoo in Germany that they can reliably sense weak electric fields in the water with their long snouts.

The discovery hints at the possibility that some marine mammals really can sniff out the electric currents of small prey buried in the sand. They might even use the skill to sense Earth's magnetic field.

To date, only one other 'true' placental mammal on Earth has been found to possess electroreceptors. Little more than a decade ago, scientists demonstrated that the common Guiana dolphin (Sotalia guianensis) evolved its own unique system of electroreception – one that is inherently different to fish, amphibians, and monotremes, like platypuses and echidnas.

Experiments now suggest that adult bottlenose dolphins and Guiana dolphins can both do something oddly similar with a line of sensitive pores on their snouts, called vibrissal crypts. These little holes used to hold juvenile whiskers, and they are extremely sensitive.

In experiments, bottlenose dolphins were able to use these ex-whisker pits to sense very weak electric fields as low as 2.4 and 5.5 microvolts per centimeter – a detection threshold that the researchers say is "in the same order of magnitude as those in the platypus" and also similar to Guiana dolphins.

https://journals.biologists.com/jeb/article/226/22/jeb245845/334721...

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