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Comment by Dr. Krishna Kumari Challa on September 30, 2023 at 12:53pm

Self-healing of synthetic diamonds observed at room temperature

A team of chemists, materials scientists and aeronautical engineers, reports evidence of self-healing in a sample of synthetic diamond at room temperature.

In their study, reported in the journal Nature Materials, the group created samples of microwire diamonds, caused them to crack and then used an electron microscope to watch them heal. The editors at Nature have also published a Research briefing in the same journal issue outlining the work.

Ever since scientists discovered that diamonds could be made not only in the lab but also in industrial settings, work has been ongoing to find ways to make them less prone to cracking, which limits their use in a wide variety of applications. Prior research has shown that if diamonds are made using a hierarchical internal structure, they become less prone to cracking—but not enough to allow their use in desired applications. More recently, scientists have discovered that nanotwinned diamond composites (ntDC) have some degree of self-healing. But these observations were made with tests conducted at high pressure and temperatures. In this new effort, the research team wondered if similar types of self-healing might be possible at normal pressure and room temperature. To find out, the researchers created several ntDC nanotwinned samples using onion carbon compressed at very high temperatures. They then set up DSC and ntDC nanobeams using an ion beam technique. After mounting ntDC samples, the nanobeams were used to create cracks in the samples, the results of which were viewed using a scanning electron microscope. To ensure their results were reliable, the team conducted multiple fracture tests.

The research team observed self-healing in the ntDC samples. Testing showed the healed samples had a tensile strength of 34%. In studying the healed samples, the researchers found the presence of sp² and sp³-hybridized carbon atoms on opposite sides of cracks, which they describe as osteoblasts; these allowed for healing as they bonded with one another. The team also conducted simulations of what they observed and found that such interactions triggered C-C re-bonding across gaps, allowing healing.

Keliang Qiu et al, Self-healing of fractured diamond, Nature Materials (2023). DOI: 10.1038/s41563-023-01656-4

Fractured diamond can heal itself at room temperature, Nature Materials (2023). DOI: 10.1038/s41563-023-01665-3

Comment by Dr. Krishna Kumari Challa on September 30, 2023 at 9:43am

To figure out why cells have a DNA region that makes cancer worse, the team generated mice without this DNA region, and found these mice do not form a separate passage for air and food in their throat as they develop. Thus, this potentially dangerous cancer-enhancer region is likely in the human genome to regulate airway formation as the human body forms. However, if a developing cancer cell opens this region, it will form a tumor that grows faster and is more dangerous for the patient.

The researchers also found that two proteins known to have a role in the developing airways, FOXA1 and NFIB, are now regulating SOX2 in breast cancer.

The enhancer is activated by the FOXA1 protein and suppressed by the NFIB protein. This means that drugs suppressing FOXA1 or activating NFIB may lead to improved treatments for bladder, uterine, breast and lung cnacer.

Now that scientists know how the SOX2 gene is activated in certain types of cancers, they can look at why this is happening by asking,  "Why did the cancer cells end up on the wrong page of the genome recipe book?"

Luis E Abatti et al, Epigenetic reprogramming of a distal developmental enhancer cluster drives SOX2 overexpression in breast and lung adenocarcinoma, Nucleic Acids Research (2023). DOI: 10.1093/nar/gkad734

Part 2

Comment by Dr. Krishna Kumari Challa on September 30, 2023 at 9:40am

Researchers find a cancer enhancer in the genome that drives tumor cell growth

Researchers have found that cancer cells can enhance tumor growth by hijacking enhancer DNA normally used when tissues and organs are formed. The mechanism, called enhancer reprogramming, occurs in bladder, uterine, breast and lung cancer, and could cause these types of tumors to grow faster in patients.

The results also pinpoint the role that specific proteins play in regulating the enhancer region which may lead to improved treatments for these cancer types. Living cells, even cancer cells, follow instructions in the genome to turn genes on and off in different contexts. The genome is like a recipe book written in DNA that gives instructions on making all the parts of the body. In each organ, only the recipes relevant to that organ should be followed, whether it's the instructions for lung, breast or some other tissue. Like flipping pages in a recipe book, the DNA containing the instructions for turning genes on in the lung is open and used in the lung, for example, but closed and ignored in other types of cells.

Scientists know that some cancer cells are opening the wrong pages in the recipe book—ones that contain the SOX2 gene, which can cause tumours to grow uncontrollably. They wanted to find out: how does the gene become expressed in cancer cells?

The researchers analyzed genome data to look for enhancer DNA that could activate SOX2 in cancer cells. The enhancer they found is open in many different types of patient tumors, meaning this could be a cancer enhancer active in bladder, uterus, breast and lung tumors. Unlike many cancer-causing changes, this enhancer reprogramming mechanism does not arise out of mutation due to DNA damage; it is caused by part of the genome opening when it should be staying closed.

The researchers then determined that the enhancer causes increased cancer cell growth because when they removed the enhancer in lab-grown cells, the cancer cells created fewer new tumour colonies.

Part 1

Comment by Dr. Krishna Kumari Challa on September 30, 2023 at 9:24am

Scientists zero in on the life-threatening fungus, Candida auris' ability to stick

In 2009, a mysterious fungus emerged seemingly from out of thin air, targeting the most vulnerable among us. The fungus in question poses a very real threat. Scientists are trying to figure out what makes the life-threatening fungus Candida auris tick—and why even the best infection control protocols in hospitals and other care settings often fail to get rid of it.

Researchers have now zeroed in on C. auris' uncanny ability to stick to everything from skin to catheters and made a startling discovery.

They discovered that C. auris is unlike any other known fungus in that it employs a type of protein, called an adhesin, that acts very similar to those used by oceanic organisms, such as barnacles and mollusks.

The new adhesin is only present in C. auris so we don't know where it came from evolutionarily. It doesn't look like it came from any other organisms by sequence similarity. The bonds formed by Scf1, they revealed, are cation-pi bonds, which are among the strongest non-covalent chemical bonds in nature.

Furthermore, the team discovered that SCF1 was associated with increased colonization and an enhanced ability to cause disease. Using mouse models, they demonstrated that a loss of both SCF1 and IFF4109 diminished the ability of a strain of C. auris to colonize skin and an in-dwelling catheter. What's more, strains designed to over express SCF1 saw enhanced virulence and more fungal lesions.

It could be that adhesin is required to get attached to blood vessels,  or maybe it changes the host-receptor interactions which has been true for the related fungus Candida albicans, but we don't know in this case yet.

Darian J. Santana et al, A Candida auris –specific adhesin, Scf1 , governs surface association, colonization, and virulence, Science (2023). DOI: 10.1126/science.adf8972

Comment by Dr. Krishna Kumari Challa on September 29, 2023 at 9:12am

Fire- safe fuel!

 Chemical engineers have designed a fuel that ignites only with the application of electric current. Since it doesn't react to flames and cannot start accidental fires during storage or transport, it is a "safe" liquid fuel.

The fuel we're normally using is not very safe. It evaporates and could ignite, and it's difficult to stop that. 

It is much easier to control the flammability of our fuel and stop it from burning when we remove voltage.

When fuel combusts, it is not the liquid itself that burns. Instead, it is the volatile fuel molecules hovering above the liquid that ignite on contact with oxygen and flame. Removing an oxygen source will extinguish the flame, but this is difficult to do outside of an engine.

If you throw a match into a pool of gasoline on the ground, it's the vapor of the gas that's burning. You can smell that vapor and you instantly know it's volatile. If you can control the vapour, you can control whether the fuel burns.

The base of the new fuel is an ionic liquid, which is a form of liquified salt. It is similar to the salt we use to flavour food, which is sodium chloride. The one researchers used for this project has a lower melting point than table salt, low vapour pressure, and is organic.

Once in the lab, the research team modified the ionic liquid's formula, replacing the chlorine with perchlorate. Then, they used a cigarette lighter to see if the resulting liquid would burn. 

Next the team tried an application of voltage followed by a lighter flame, which did ignite. Once they shut off the current, the flame was gone, and they were able to repeat that process over and over again—applying voltage, seeing smoke, lighting the smoke so it burned, then turning it off. It's a system they could start and stop very quickly.

Adding more voltage to the liquid resulted in larger flames with more energy output. As such the approach could also act like a metering or throttling system in an engine.

Prithwish Biswas et al, Electrochemical Modulation of the Flammability of Ionic Liquid Fuels, Journal of the American Chemical Society (2023). DOI: 10.1021/jacs.3c04820

Comment by Dr. Krishna Kumari Challa on September 29, 2023 at 8:24am

Recessive genes make the carrot colour orange

A new study of the genetic blueprints of more than 600 types of carrot shows that three specific genes are required to give carrots an orange color. Surprisingly, these three required genes all need to be recessive, or turned off. The paper's findings shed light on the traits important to carrot improvement efforts and could lead to better health benefits from the vegetable.

Normally, to make some function, you need genes to be turned on. In the case of the orange carrot, the genes that regulate orange carotenoids—the precursor of vitamin A that have been shown to provide health benefits—need to be turned off.

According to the researchers, orange carrot could have resulted from white and yellow carrot crosses, as white and yellow carrots are at the base of the phylogenetic tree for the orange carrot. Also, carotenoids got their name because they were first isolated from carrots.

Population genomics identifies genetic signatures of carrot domestication and improvement and uncovers the origin of high carotenoid orange carrots, Nature Plants (2023). DOI: 10.1038/s41477-023-01526-6

Comment by Dr. Krishna Kumari Challa on September 29, 2023 at 8:03am

An adhesive and stretchable epicardial patch to precisely monitor the heart's activity

Epicardial patches are carefully engineered tissue patches that can be placed near or on a patient's heart. These devices can help doctors to diagnose and treat a variety of heart conditions, including arrhythmia and heart attacks (i.e., myocardial infarctions).

In recent years, several engineers and medical researchers have been trying to develop these devices, yet many solutions proposed so far are not ideal. Specifically, most epicardial patches created so far are designed to be affixed onto the heart via a medical procedure known as "suturing," which can be both challenging and risky. Researchers recently developed an alternative epicardial patch that could be much easier to apply in clinical settings. This patch, introduced in Nature Electronics, is both stretchable and adhesive; thus, it does not need to be affixed onto a patient's heart through the suturing process.

Considering the highly irregular surface of the heart, the existing devices with low adhesiveness often become detached due to continuous cardiac contraction/relaxation in long term. To overcome such issues, facile and instantaneous and even robust adhesion to cardiac tissues is essential. Furthermore, when attached to the heart for an extended period, the materials used in epicardial devices should be exceptionally soft to avoid causing any tissue compression.

Researchers set out to develop a new adhesive epicardial patch that effectively overcomes the limitations of previously proposed designs. The patch they created now can be instantly attached to tissue on the heart's surface and could easily be fabricated on a large-scale.

Notably, their patch does not exert any unnecessary pressure on the heart's tissue for extended periods of time, which could improve both its safety and efficacy. It is comprised of three different but co-existing materials, namely a liquid-phase conducting composite, a network-shaped substrate, and an ionic adhesive.

The combination of these materials eliminates the need to suture the patch to the heart, making it easy to implement for medical professionals with varying degrees of experience, while also reducing the risk of complications associated with the suturing procedure.

 Heewon Choi et al, Adhesive bioelectronics for sutureless epicardial interfacing, Nature Electronics (2023). DOI: 10.1038/s41928-023-01023-w

Comment by Dr. Krishna Kumari Challa on September 28, 2023 at 9:52am

Ultrasound enables gene delivery throughout the brain

Researchers tested the safety and feasibility of gene delivery to multiple brain regions using a noninvasive, ultrasound-based technique in rodents, and their findings suggest that the efficiency of gene delivery improves within each targeted site when more sites are opened.

The work used focused ultrasound energy to safely make the blood-brain barrier permeable. The technique is known as focused ultrasound blood-brain barrier opening (FUS-BBBO). 

The procedure also permits the passage of proteins and other small molecules in the other direction—that is, from the brain into the bloodstream—where they can be readily sampled.

Many disorders affect large brain regions or the entire brain, but delivery of gene therapy to these regions is difficult. 

When a gene-delivery vector is injected into the brain with a needle, it often only diffuses a few millimeters. To treat the entire brain, one would need to perform thousands of injections, which would be difficult and possibly harmful. With FUS-BBBO, such surgical delivery could be circumvented.

Researchers now tested the efficiency and safety of opening 105 sites simultaneously with positive results in most regions of the brain. Surprisingly, their findings suggest that the efficiency of gene delivery improves within each targeted site when more sites are opened.

 Shirin Nouraein et al, Acoustically targeted noninvasive gene therapy in large brain volumes, Gene Therapy (2023). DOI: 10.1038/s41434-023-00421-1

Comment by Dr. Krishna Kumari Challa on September 28, 2023 at 9:35am

 Why our skin feels 'tight' after washing

When we wash our face with a cleanser, our skin can start to feel tight. With the application of a favorite moisturizer, that feeling often goes away. This perception of our skin might seem subjective, but researchers recently revealed the mechanism behind these feelings.

Their work, published in PNAS Nexus, demonstrates how mechanical changes at the outer surface of our skin translate into sensations and provides a quantitative approach for determining how people will perceive their skin after using a moisturizer or cleanser.

Our skin is the largest organ in our body and it's constantly exposed to the environment around us. The outermost layer of our skin—the stratum corneum—acts as a barrier to keep out unwanted chemicals and bacteria and to keep in moisture. When we use a harsh cleanser, it strips away some of the lipids that hold in moisture, causing the stratum corneum to contract. A good moisturizer increases the water content of the stratum corneum, causing it to swell.

 The mechanical forces created by this shrinking or swelling propagate through the skin to reach mechanoreceptors—sensory receptors that turn mechanical force into neurological signals—below the epidermis, which then fire off signals to the brain that we interpret as a feeling of skin tightness.

The researchers studied the effects of nine different moisturizing formulas and six different cleansers on donor skin samples from three locations on the human body—cheek, forehead, and abdomen. They measured changes in the stratum corneum in the lab and then fed that information into a sophisticated model of human skin to predict the signals that the mechanoreceptors would send.

Ross Bennett-Kennett et al, Sensory neuron activation from topical treatments modulates the sensorial perception of human skin, PNAS Nexus, (2023) DOI: 10.1093/pnasnexus/pgad292. academic.oup.com/pnasnexus/art … /2/9/pgad292/7278834

Comment by Dr. Krishna Kumari Challa on September 28, 2023 at 9:19am

An artist's conceptual rendering of the antihydrogen atoms contained within the magnetic trap of the ALPHA-g apparatus. As the field strength at the top and bottom of the magnetic trap is reduced, the antihydrogen atoms escape, touch the chamber walls and annihilate. Most of the annihilations occur beneath the chamber, showing that gravity is pulling the antihydrogen down.

Jeffrey Hangst, Observation of the effect of gravity on the motion of antimatter, Nature (2023). DOI: 10.1038/s41586-023-06527-1. www.nature.com/articles/s41586-023-06527-1

Anna Soter, Free-falling antihydrogen reveals the effect of gravity on antimatter, Nature (2023). DOI: 10.1038/d41586-023-02930-w , www.nature.com/articles/d41586-023-02930-w

Part 2

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