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Comment by Dr. Krishna Kumari Challa on March 23, 2019 at 8:05am

Scientists Watched  as Heat Moved at the Speed of Sound!

A rare phenomenon seen in just a handful of materials at forbidding temperatures has been detected within “warm” graphite—a finding that could aid future microelectronics.

http://science.sciencemag.org/content/early/2019/03/13/science.aav3548

Comment by Dr. Krishna Kumari Challa on March 2, 2019 at 11:53am

Night-vision ‘super-mice’ created using light-converting nanoparticles

The particles bind to photoreceptors in the eyes and convert infrared wavelengths to visible light.

Mice with vision enhanced by nanotechnology were able to see infrared light as well as visible light, reports a study published February 28 in the journal Cell. A single injection of nanoparticles in the mice's eyes bestowed infrared vision for up to 10 weeks with minimal side effects, allowing them to see infrared light even during the day and with enough specificity to distinguish between different shapes. These findings could lead to advancements in human infrared vision technologies, including potential applications in civilian encryption, security, and military operations.
Humans and other mammals are limited to seeing a range of wavelengths of light called visible light, which includes the wavelengths of the rainbow. But infra red variation, which has a longer wavelength, is all around us. People, animals and objects emit infrared light as they give off heat, and objects can also reflect infrared light.

"When light enters the eye and hits the retina, the rods and cones—or photoreceptor cells—absorb the photons with visible light wavelengths and send corresponding electric signals to the brain," says Han. "Because infra resd wavelengths are too long to be absorbed by photoreceptors, we are not able to perceive them."

In this study, the scientists made nanoparticles that can anchor tightly to photo receptor cells and act as tiny infrared light transducers. When infrared light hits the retina, the nanoparticles capture the longer infrared wavelengths and emit shorter wavelengths within the visible light range. The nearby rod or cone then absorbs the shorter wavelength and sends a normal signal to the brain, as if visible light had hit the retina.

The researchers tested the nanoparticles in mice, which, like humans, cannot see infrared naturally. Mice that received the injections showed unconscious physical signs that they were detecting infrared light, such as their pupils constricting, while mice injected with only the buffer solution didn't respond to infrared light.

To test whether the mice could make sense of the infrared light, the researchers set up a series of maze tasks to show the mice could see infrared in daylight conditions, simultaneously with visible light.

"In our study, we have shown that both rods and cones bind these nanoparticles and were activated by the near infrared light," say the researchers. "So we believe this technology will also work inhuman eyes not only for generating super vision but also for therapeutic solutions in human red color vision deficits."

Cell, Ma et al.: "Mammalian Near-Infrared Image Vision through Injectable and Self-Powered Retinal Nanoantennae." https://www.cell.com/cell/fulltext/S0092-8674(19)30101-1 , DOI: 10.1016/j.cell.2019.01.038 

Comment by Dr. Krishna Kumari Challa on February 27, 2019 at 11:00am

Scientists turn carbon dioxide back into coal!

Scientists have harnessed liquid metals to turn carbon dioxide back into solid coal, in research that offers an alternative pathway for safely and permanently removing the greenhouse gas from our atmosphere. The new technique can convert CO2 back into carbon at room temperature, a process that's efficient and scalable. A side benefit is that the carbon can hold electrical charge, becoming a supercapacitor, so it could potentially be used as a component in future vehicles.

https://www.sciencedaily.com/releases/2019/02/190226112429.htm

Comment by Dr. Krishna Kumari Challa on February 26, 2019 at 7:03am

Hachimoji DNA and RNA : A genetic system with eight building blocks!

Expanding the genetic code

DNA and RNA are naturally composed of four nucleotide bases that form hydrogen bonds in order to pair. Hoshika et al. added an additional four synthetic nucleotides to produce an eight-letter genetic code and generate so-called hachimoji DNA. Coupled with an engineered T7 RNA polymerase, this expanded DNA alphabet could be transcribed into RNA. Thus, new forms of DNA that add information density to genetic biopolymers can be generated that may be useful for future synthetic biological applications.

Researchers reported DNA- and RNA-like systems built from eight nucleotide “letters” (hence the name “hachimoji”) that form four orthogonal pairs. These synthetic systems meet the structural requirements needed to support Darwinian evolution, including a polyelectrolyte backbone, predictable thermodynamic stability, and stereoregular building blocks that fit a Schrödinger aperiodic crystal. Measured thermodynamic parameters predict the stability of hachimoji duplexes, allowing hachimoji DNA to increase the information density of natural terran DNA. Three crystal structures show that the synthetic building blocks do not perturb the aperiodic crystal seen in the DNA double helix. Hachimoji DNA was then transcribed to give hachimoji RNA in the form of a functioning fluorescent hachimoji aptamer. These results expand the scope of molecular structures that might support life, including life throughout the cosmos.

http://science.sciencemag.org/content/363/6429/884

Comment by Dr. Krishna Kumari Challa on December 5, 2018 at 6:46am

It is not common but fathers too can pass mitochondrial DNA to their children!

Fathers in three unrelated families passed mitochondria — tiny energy factories found in cells — on to their children, researchers report.

Scientists have long thought that children inherited mitochondria exclusively from their mothers, since mitochondria from the father’s sperm are usually destroyed after fertilizing the egg. The new research, published online November 26, 2018 in the Proceedings of the National Academy of Sciences, suggests that in rare cases dads can contribute mitochondria too. For now, the consequences of inheriting mitochondria from both parents aren’t known.

Mitochondrial disease researcher Paldeep Atwal spotted the paternal signature after examining DNA from a woman who came to the Mayo Clinic in Jacksonville, Fla. DNA in a cell’s nucleus is inherited equally from both parents and contains all the genetic instructions for building a body. Mitochondria have their own DNA, too, that contains some of the genes needed for building and running the organelles. The woman’s cells weirdly contained two types of mitochondrial DNA, some from mom and some “from elsewhere”. 

Thinking the result was a mistake, Atwal and colleagues repeated the test. “The same thing came back the second time, and that’s when the researchers started to get a little bit suspicious”.

The researchers had DNA from both of the woman’s parents, so the team examined the father’s mitochondrial DNA, and found that he was the source of the mystery mitochondria. The woman’s brother also inherited mitochondria from their father. 

So Atwal got in touch with Taosheng Huang, a mitochondrial disease expert at Cincinnati Children’s Hospital Medical Center. It turns out that Huang had examined patients from two other families in which fathers had handed mitochondria down to their children. All together, the researchers found 17 people in the three families who inherited 24 percent to 76 percent of their mitochondria from dad.

http://www.pnas.org/content/early/2018/11/21/1810946115

Comment by Dr. Krishna Kumari Challa on December 5, 2018 at 6:41am

New technique to do biopsy on living cells
A new set of nanotweezers can extract DNA and other single molecules from a living cell without killing it.

Examining the molecular contents of a single cell has traditionally required killing the cell by bursting it open. But that process provides only a single snapshot of the cell’s molecular makeup at the time of its death. The new nanotweezers, reported online December 3 in Nature Nanotechnology, could enable long-term analysis of what’s going on inside individual cells to better understand how healthy cells work and where diseased cells go wrong.

The nanotweezers comprise a glass rod with a tip less than 100 nanometers across, capped with two carbon-based electrodes. Applying an electric voltage to the tweezers creates a powerful electric field in the immediate vicinity of the electrodes, which can attract and trap biomolecules within about 300 nanometers of the tweezer tip.

Once caught in this 300-nanometer net, molecules are stuck until the tweezer voltage turns off. By positioning the needlelike tweezers with extreme precision, researchers can puncture specific cell compartments and fish for particular molecules.
B.P. Nadappuram et al. Nanoscale tweezers for single-cell biopsies. Nature Nanotechnology. Published online December 3, 2018. 

https://www.nature.com/articles/s41565-018-0315-8

Comment by Dr. Krishna Kumari Challa on November 2, 2018 at 8:53am

Scientists are warning that if human beings continue to mine the world’s wildernesses for resources and convert them into cities and farms at the pace of the previous century, the planet’s few remaining wild places could disappear in decades.

Today, more than 77 percent of land on earth, excluding Antarctica, has been modified by human industry, according to a study published recently in the journal Nature, up from just 15 percent a century ago.

The study, led by researchers from the University of Queensland in Australia and the Wildlife Conservation Society in New York, paints the first global picture of the threat to the world’s remaining wildernesses — and the image is bleak.

Wilderness is defined as an area not subject to direct human use.

These areas are the only places on earth that have natural levels of biodiversity, and can continue to sustain plant and animal species on an evolutionary time scale.

Moreover, these spots often act as the world’s lungs, storing carbon dioxide that would otherwise be released into the atmosphere.

Policy experts, take note that even more aggressive action is needed to stop global resource extraction and industrial expansion. 

Healthy ecosystems are crucial in their own right for biodiversity and mitigating climate change, but more importantly, said the researchers, they are home for hundreds of millions of indigenous people, who rely on the wilderness to survive and thrive.

Comment by Dr. Krishna Kumari Challa on October 31, 2018 at 10:03am

60% of world's wildlife has been wiped out since 1970 says WWF

Well over half the world's population of vertebrates, from fish to birds to mammals, have been wiped out in the past four decades, says a new report from the World Wildlife Fund.

Between 1970 and 2014, there was 60 per cent decline, on average, among 16,700 wildlife populations around the world according to the 2018 edition of the Living Planet Report  released recently.

We've had a loss of nearly two-thirds, on average, of our wild species. The magnitude of that should be eye opening… We really are reaching a point where we're likely to see species go extinct.

The WWF says the biggest drivers of the declines are habitat loss and overexploitation, but says climate change is a growing threat. The results of the new report shows a trend in the wrong direction, and "there's a real urgency" to take action to protect wildlife.

Comment by Dr. Krishna Kumari Challa on October 25, 2018 at 10:07am

Brain-eating amoebae halted by silver nanoparticles

Researchers have developed silver nanoparticles coated with anti-seizure drugs that can kill brain-eating amoebae while sparing human cells. The researchers report their results in ACS Chemical Neuroscience.

Although infections with brain-eating amoebae (Naegleria fowleri) are rare, they are almost always deadly. Most cases result from inhaling warm, dirty water in ponds, hot springs or unchlorinated swimming pools. Another species, Acanthamoeba castellanii, can cause blindness by entering the eyes through dirty contact lenses. Common treatments include antimicrobial drugs, but they often cause severe side effects because of the high doses required for them to enter the brain. Ayaz Anwar and colleagues wondered if three anti-seizure drugs -- diazepam, phenobarbitone and phenytoin -- could kill amoebae, alone or in combination with silver nanoparticles. The drugs are already approved by the U.S. Food and Drug Administration and are known to cross the blood-brain barrier. The researchers reasoned that they might be more effective when attached to silver nanoparticles, which can improve the delivery of some drugs and also have their own antimicrobial effects.

The team chemically attached the drugs to silver nanoparticles and examined their ability to kill amoebae. They found that each of the three drugs alone could kill N. fowleri and A. castellanii, but they worked much better when bound to silver nanoparticles. The drug-nanoparticle combos protected human cells from the microbes, increasing their survival rate compared with untreated infected human cells. The researchers propose that these repurposed drugs, aided by the nanoparticles, might kill amoebae by binding to protein receptors or ion channels on the single-celled organism's membrane.

https://pubs.acs.org/doi/abs/10.1021/acschemneuro.8b00484

Comment by Dr. Krishna Kumari Challa on October 24, 2018 at 9:59am

Microplastics have been found in the human food chain as particles made of polypropylene (PP), polyethylene-terephthalate (PET) and others were detected in human stools, research presented recently at the 26th UEG Week in Vienna reveals.

Researchers from the Medical University of Vienna and the Environment Agency Austria monitored a group of participants from countries across the world, including Finland, Italy, Japan, the Netherlands, Poland, Russia, the UK and Austria. The results show that every single stool sample tested positive for the presence of microplastic and up to nine different plastic types were identified.

Microplastics are small particles of plastic less than 5mm and are used in various products for specific purposes; as well as being created unintentionally by the breaking down of larger pieces of plastic through weathering, degradation, wear and tear. Microplastic may impact human health via the GI tract where it could affect the tolerance and immune response of the gut by bioaccumulation or aiding transmission of toxic chemicals and pathogens.
The stools were tested at the Environment Agency Austria for 10 types of plastics following a newly developed analytical procedure. Up to nine different plastics, sized between 50 and 500 micrometres, were found, with polypropylene (PP) and polyethylene terephthalate (PET) being the most common. On average, the researchers found 20 microplastic particles per 10g of stool.
Schwabl, P. et al (2018), Assessment of microplastic concentrations in human stool - Preliminary results of a prospective study, Presented at UEG Week 2018 Vienna, October 24, 2018.

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