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Comment by Dr. Krishna Kumari Challa on November 5, 2023 at 11:43am

A living bandage: Wound dressing uses probiotic bacteria to combat biofilms

Chronic wounds: If an injury has not healed after four weeks, there is a wound healing disorder. Sometimes, seemingly harmless tissue damage can develop into a permanent health problem or even blood poisoning.

Treatment is particularly difficult because germs that know how to protect themselves perfectly settle here. These bacteria form a biofilm, a stubborn compound of various pus pathogens. For their own protection, they produce a layer of mucus with which they attach themselves to surfaces. Antibiotics or disinfectants reach their limits because they cannot get to the dangerous germs.

A research team  is currently developing a wound dressing that uses "good" probiotic bacteria to combat biofilms. The researchers recently published a proof of concept in the journal Microbes and Infection.

They used living probiotic bacteria for the new dressing. They are found in healthy intestinal flora and play a major role in the production of foods such as yogurt and cheese. The used probiotic lactobacilli are biocompatible and create an acidic environment by producing lactic acid. 

This is intended to push the unfavourable, alkaline pH in chronic wounds in the right, i.e., acidic, direction. In the laboratory experiments, the bacteria were able to induce a strongly acidic pH of 4 in the culture medium. At the same time, the probiotics promoted the migration of human fibroblasts under the investigated conditions.

Finally, the beneficial bacteria were integrated into a dressing that protects chronic wounds from further infection. This also allowed the living lactobacilli to produce lactic acid in a protected environment. As desired, the dressing released the acidic product into the environment in a controlled and steady manner.

In laboratory tests, the dressing material with integrated probiotics was able to completely remove a typical biofilm of skin pathogens in a culture dish. The question now was: Does the dressing containing beneficial bacteria also pass the test with human skin?

The researchers created artificial wounds with a diameter of two millimeters on small tissue samples and allowed a biofilm of wound pathogen Pseudomonas aeruginosa to grow. In this three-dimensional model of a human skin infection, the probiotics-containing dressing reduced the number of pathogens by 99.999%. In addition, the researchers were able to prove that the probiotics do not harm human skin cells and triggers the production of inflammatory response of the cells.

Zhihao Li et al, Topical application of Lactobacilli successfully eradicates Pseudomonas aeruginosa biofilms and promotes wound healing in chronic wounds, Microbes and Infection (2023). DOI: 10.1016/j.micinf.2023.105176

Comment by Dr. Krishna Kumari Challa on November 4, 2023 at 12:21pm

Cancer trial results show power of weaponized antibodies

Tumour-targeting antibodies coupled with toxic chemicals are an unprecedented success in treating bladder cancer.

A combination of two drugs cuts the risk of death in people with bladder cancer by m..., compared with conventional chemotherapy. It’s an unprecedented result in a cancer for which survival rates have been almost unchanged since the 1980s. The treatment consists of pembrolizumab, which allows the body to attack tumours more effectively, and an antibody–drug conjugate, enfortumab vedotin, which delivers a toxic agent directly to cancer cells.

https://www.nature.com/articles/d41586-023-03421-8?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa on November 4, 2023 at 11:39am

How can we avoid drinking forever chemicals and arsenic?

per- and polyfluoroalkyl substances, also known as PFAS or forever chemicals, which are used to protect clothing, cookware, cosmetics, and other products from water, grease, or oil. But those chemicals can leach out of those goods to haunt our food, air, plants, and drinking water. So far, scientists have found that PFAS exposure could lead to liver and immune system damage, increased risk of kidney or testicular cancer, birth defects, and other health and environmental problems.

And one of the most common ways to ingest these chemicals is through contaminated water.

PFAS are typically present at really, really low concentrations. But they can be carcinogenic even at low concentrations.

Luckily, we can extract PFAS and other unwanted contaminants, like arsenic or calcium, from our water using a process called ion exchange. And soon, removing PFAS will not be optional. In June 2023, the Environmental Protection Agency announced its plan to require water utilities to reach near-zero levels of PFAS in drinking water. That means many water treatment facilities will need to upgrade their systems to target this insidious chemical.

And ion exchange technologies are some of the only selective separation technologies we have that can get these forever chemicals out of water.

Source: US National Renewable Energy Laboratory  

Comment by Dr. Krishna Kumari Challa on November 4, 2023 at 11:06am

There are various biomedical markers present in cancerous tissues at higher concentrations than in healthy tissues—amino acids (building blocks of proteins), proteins, and enzymes. When excited with UV light, these markers light up and fluoresce in the UV and part of the visible spectrum, in a process called autofluorescence. 

Because cancer and healthy cells have different concentrations of markers and therefore different spectral signatures, the two classes of cells can be differentiated based on their fluorescence in the UV spectrum. The team evaluated their imaging device on its ability to discriminate cancer-related markers and found that is capable of differentiating between cancer and healthy cells with 99% confidence.

One of the biggest challenges is knowing how much tissue to remove to ensure clear margins and such a sensor can help facilitate the decision making process when a surgeon is removing a cancerous tumor.

"This new imaging technology is enabling us to differentiate cancerous versus healthy cells and is opening up new and exciting applications beyond just health.

Cheng Chen et al, Bioinspired, vertically stacked, and perovskite nanocrystal–enhanced CMOS imaging sensors for resolving UV spectral signatures, Science Advances (2023). DOI: 10.1126/sciadv.adk3860. www.science.org/doi/10.1126/sciadv.adk3860

Part 3

Comment by Dr. Krishna Kumari Challa on November 4, 2023 at 11:03am

Humans have trichromatic vision with three photoreceptors, where every color perceived can be made from a combination of red, green and blue. Butterflies, however, have compound eyes, with six (or more) photoreceptor classes with distinct spectral sensitivities. In particular, the Papilio xuthus, a yellow, Asian swallowtail butterfly, has not only blue, green and red, but also violet, ultraviolet and broadband receptors. Further, butterflies have fluorescent pigments that allow them to convert UV light into visible light which can then be easily sensed by their photoreceptors. This allows them to perceive a broader range of colors and details in their environment.

Beyond the increased number of photoreceptors, butterflies also exhibit a unique tiered structure in their photoreceptors. To replicate the UV sensing mechanism of the Papilio xuthus butterfly, the UIUC team has emulated the process by combining a thin layer of PNCs with a tiered array of silicon photodiodes.

PNCs are a class of semiconductor nanocrystals that display unique properties similar to that of quantum dots—changing the size and composition of the particle changes the absorption and emission properties of the material. In the last few years, PNCs have emerged as an interesting material for different sensing applications, such as solar cells and LEDs. PNCs are extremely good at detecting UV (and even lower) wavelengths that traditional silicon detectors are not. In the new imaging sensor, the PNC layer is able to absorb UV photons and re-emit light in the visible (green) spectrum which is then detected by the tiered silicon photodiodes. Processing of these signals allows for mapping and identification of UV signatures.

Part 2

Comment by Dr. Krishna Kumari Challa on November 4, 2023 at 11:03am

Seeing the unseen: How butterflies can help scientists detect cancer

There are many creatures on our planet with more advanced senses than humans. Turtles can sense Earth's magnetic field. Mantis shrimp can detect polarized light. Elephants can hear much lower frequencies than humans can. Butterflies can perceive a broader range of colors, including ultraviolet (UV) light.

Inspired by the enhanced visual system of the Papilio xuthus butterfly, a team of researchers have developed an imaging sensor capable of "seeing" into the UV range inaccessible to human eyes. The design of the sensor uses stacked photodiodes and perovskite nanocrystals (PNCs) capable of imaging different wavelengths in the UV range. Using the spectral signatures of biomedical markers, such as amino acids, this new imaging technology is even capable of differentiating between cancer cells and normal cells with 99% confidence.

Researchers have taken inspiration from the visual system of butterflies, who are able to perceive multiple regions in the UV spectrum, and designed a camera that replicates that functionality. They did this by using novel perovskite nanocrystals, combined with silicon imaging technology, and this new camera technology can detect multiple UV regions.

UV light is electromagnetic radiation with wavelengths shorter than that of  visible light(but longer than X-rays). We are most familiar with UV radiation from the sun and the dangers it poses to human health. UV light is categorized into three different regions—UVA, UVB and UVC— based on different wavelength ranges. Because humans cannot see UV light, it is challenging to capture UV information, especially discerning the small differences between each region.

Butterflies, however, can see these small variations in the UV spectrum, like humans can see shades of blue and green.UV light is incredibly difficult to capture, it just gets absorbed by everything, and butterflies have managed to do it extremely well.

Part 1

Comment by Dr. Krishna Kumari Challa on November 4, 2023 at 9:34am

Researchers find evidence of mpox circulating in humans since 2016

A large international team of medical researchers and epidemiologists has found evidence that monkeypox (mpox) has been circulating in humans since 2016. In their study, reported in the journal Science, the group used Bayesian evolutionary analysis of the mpox virus to show that its genomic history includes years of change due to human infections.

Mpox was first identified in the 1950s after an illness struck a group of research monkeys in Denmark. Twenty years later, the first case was detected in a human in Africa. Over the following decades, several cases of the disease were seen in humans and all were attributed to the virus jumping from other mammals.

Then, in 2017, an outbreak occurred in Nigeria and by 2022, it had spread across the globe, demonstrating that the virus had evolved to jump from human to human. In this new effort, the research team took a closer look at the genome of the virus behind mpox to learn more about its evolutionary history, particularly how it relates to human infections. The researchers sequenced the genome of the mpox virus to learn more about its evolutionary history. They found that the clade IIb was the one that had spread around the world. They also noted that it looked different from other strains that had been seen before in Africa.

They found a mutation that had led to the production of an enzyme called APOBEC3, which was found to cause further mutations that alter genome base pairs. It was also found to have come about due to infections in humans. That allowed the team to trace the evolutionary history of the virus as it infected humans—they found such mutations going back to approximately 2016, which strongly suggests that the virus has been transmittable between humans since that year. The research team concludes that there is a strong likelihood of multiple cases of small mpox outbreaks that have not been recognized, allowing the virus to spread under the radar. They further suggest stronger surveillance methods be established because the virus is still mutating rapidly and could become deadlier.

Áine O'Toole et al, APOBEC3 deaminase editing in mpox virus as evidence for sustained human transmission since at least 2016, Science (2023). DOI: 10.1126/science.adg8116

Comment by Dr. Krishna Kumari Challa on November 4, 2023 at 9:29am

If the sensors succeed in more extensive trials, the scientists said, the possible applications for spaceflight are many—from helping astronauts land safely on the surface of a planet, to supporting them as they move outside a vehicle in space.

Vibrotactile Feedback as a Countermeasure for Spatial Disorientation, Frontiers in Physiology (2023). DOI: 10.3389/fphys.2023.1249962
Part 3
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Comment by Dr. Krishna Kumari Challa on November 4, 2023 at 9:28am

The researchers used sensory deprivation and a multi-axis rotation device to test their vibrotactors in simulated spaceflight, so the senses participants would normally rely on were useless. Could the vibrotactors correct the misleading cues the participants would receive from their vestibular systems, and could participants be trained to trust them?

In total, 30 participants were recruited, of whom 10 received training to balance in the rotation device, 10 received the vibrotactors, and the remaining 10 received both. All participants were shown a video of the rotation device and told how it worked: moving like an inverted pendulum until it reached a crash boundary, unless it was stabilized by a person sitting in the device controlling it with a joystick.

Additional training, for the participants who received it, included tasks that taught participants to disengage from their vestibular sense and rely on the vibrotactors instead of their natural gravitational cues. These tasks involved searching for hidden non-upright balance points, which meant participants had to ignore their desire to align to upright and focus on the vibrotactors.

All participants were given a blindfold, earplugs, and white noise to listen to. Those with vibrotactors had four strapped to each arm, which would buzz when they moved away from the balance point. Each participant took part in 40 trials, aiming to keep the rotation device as close to the balance point as possible.

For half the trials, the rotation device operated on a vertical roll plane. This was considered an Earth analog because participants could use their natural gravitational cues for orientation. During the second half, which acted as a spaceflight analog, the rotation device operated on a horizontal roll plane where those gravitational cues could no longer help.

After each block of trials, participants were asked to rate how disoriented they felt and how much they trusted the vibrotactors. The scientists measured their success by looking at how often they crashed and how well they controlled their balance.
All the groups were initially disoriented in the spaceflight analog. The scientists expected this, because participants could not rely on the natural gravitational cues that they usually use. Nearly all participants reported that they trusted the vibrotactors, but they also reported confusion from conflicts between their internal cues and the vibrotactors.

The participants wearing vibrotactors still performed better than those who only received training. The training-only group crashed more frequently, moved around the balance point more, and accidentally destabilized themselves more often. Receiving the training did help, though. As the trials continued, the group who received both training and vibrotactors performed best.

However, even with training, the participants didn't perform as well as they did in the Earth analog. They may have needed more time to integrate cues from the vibrotactors, or the buzzing from the vibrotactors may not have given a strong enough danger signal.

"A pilot's cognitive trust in this external device will most likely not be enough" . "Instead, the trust has to be at a deeper—almost sub-cognitive—level. To achieve this, specialized training will be required."
Part 2

Comment by Dr. Krishna Kumari Challa on November 4, 2023 at 9:27am

Wearable devices may prevent astronauts getting 'lost' in space

Taking space  flight is dangerous. In leaving the Earth's surface, we lose many of the cues we need to orient ourselves, and that spatial disorientation can be deadly. Astronauts normally need intensive training to protect against it. But scientists have now found that wearable devices which vibrate to give orientation cues may boost the efficacy of this training significantly, making spaceflight slightly safer.

Long-duration spaceflight will cause many physiological and psychological stressors, which will make astronauts very susceptible to spatial disorientation. When disoriented, an astronaut will no longer be able to rely on their own internal sensors, which they have depended on for their whole lives.
Part 1

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