Comment

Comment by Dr. Krishna Kumari Challa on November 7, 2020 at 6:18am

Seeing dark matter in a new light

A small team of astronomers have found a new way to 'see' the elusive dark matter haloes that surround galaxies, with a new technique 10 times more precise than the previous-best method.

Scientists currently estimate that up to 85% of the mass in the universe is effectively invisible. This "dark matter" cannot be observed directly, because it does not interact with light in the same way as the ordinary matter that makes up stars, planets, and life on Earth.

So how do we measure what cannot be seen? The key is to measure the effect of gravity that the dark matter produces. It's like looking at a flag to try to know how much wind there is. You cannot see the wind, but the flag's motion tells you how strongly the wind is blowing.

The new research focuses on an effect called weak gravitational lensing, which is a feature of Einstein's general theory of relativity. The dark matter will very slightly distort the image of anything behind it.

Weak gravitational lensing is already one of the most successful ways to map the dark matter content of the Universe. Now, the team has used the ANU 2.3m Telescope in Australia to map how gravitationally lensed galaxies are rotating. Because we know how stars and gas are supposed to move inside galaxies, we know roughly what that galaxy should look like. By measuring how distorted the real galaxy images are, then we can figure out how much dark matter it would take to explain what we see. The new research shows how this velocity information enables a much more precise measurement of the lensing effect than is possible using shape alone.

Pol Gurri et al. The first shear measurements from precision weak lensing, Monthly Notices of the Royal Astronomical Society (2020). DOI: 10.1093/mnras/staa2893

https://phys.org/news/2020-11-dark.html?utm_source=nwletter&utm...

Comment by Dr. Krishna Kumari Challa on November 6, 2020 at 8:18am

The Science Communication Crisis

Comment by Dr. Krishna Kumari Challa on November 6, 2020 at 8:13am

 2020 Heroes of Chemistry

Comment by Dr. Krishna Kumari Challa on November 6, 2020 at 8:05am

Startling Case Study Finds Asymptomatic COVID-19 Carrier Who Shed Virus For 70 Days

A team of researchers and doctors has now reported the case of one woman with leukemia who had no symptoms of COVID-19 but 70 days after her first positive test, she was still shedding infectious SARS-CoV-2 particles.

This result is much longer than previous reports of hospitalised adults found shedding infectious SARS-CoV-2 virus up to 20 days after their COVID-19 diagnosis, plus other accounts of people shedding genetic material from the virus up to 63 days after their symptoms first appeared.

The new report should alert doctors and public health experts alike to the fact that people without symptoms and with weakened immune systems, such as cancer patients, can seemingly shed the SARS-CoV-2 virus for a really long time. In this case, even months.

"Although it is difficult to extrapolate from a single patient, our data suggest that long-term shedding of infectious virus may be a concern in certain immunocompromised patients," the research team wrote in their paper describing the case.

https://www.cell.com/cell/fulltext/S0092-8674(20)31456-2

https://www.sciencealert.com/case-study-reveals-rare-patient-who-sh...

Comment by Dr. Krishna Kumari Challa on November 6, 2020 at 7:54am

How Some Vaccines Protect Against More than Their Targets

As researchers test existing vaccines for nonspecific protection against COVID-19, immunologists are working to understand how some inoculations protect against pathogens they weren’t designed to fend off.

https://www.the-scientist.com/features/how-some-vaccines-protect-ag...

Comment by Dr. Krishna Kumari Challa on November 6, 2020 at 6:47am

New research traces the origins of trench fever

First observed among British Expeditionary Forces in 1915, trench fever sickened an estimated 500,000 soldiers during World War I. Since then, the disease has become synonymous with the battlefield. But now, new research from an international team of scientists has uncovered evidence challenging this long-held belief.

The research, published this week in PLOS ONE, outlines the discovery of DNA evidence of the disease in civilian remains predating WWI by thousands of years. In total, the team analyzed bone fragments and teeth of 145 individuals alive between the 1st and 19th centuries. Approximately 20% of those remains contained traces of Bartonella quintana, the bacteria responsible for trench fever. 

Epidemiologists and researchers used real-time polymerase chain reaction testing to detect B. quintana DNA within the remains.

Once contracted, there are diseases, like trench fever, that can leave traces within your DNA and can integrate your DNA with further information. This means that once a person dies, even as far back as 2,000 years ago, it is still possible to find traces of the bacterium that infected them.

 The discovery sheds light on the complex history of trench fever and begins answering historical questions about the lives of people in this region during the 3rd and 4th centuries.

While most associate this disease with WWI and WWII, occurrences of trench fever are still reported today, most prominently within homeless populations. The bacteria are spread to humans through contact with body lice (Pediculus humanus corporis), making poor personal hygiene a primary factor in its spread and infection rate. Researchers hope that by tracing the progression of B. quintana through history, they're able to identify ways to better manage the spread of the disease today.

Ba-Hoang-Anh Mai et al, Five millennia of Bartonella quintana bacteraemia, PLOS ONE (2020). DOI: 10.1371/journal.pone.0239526

https://phys.org/news/2020-11-trench-fever.html?utm_source=nwletter...

Comment by Dr. Krishna Kumari Challa on November 6, 2020 at 6:40am

The biggest trees capture the most carbon: Large trees dominate carbon storage in forests

Older, large-diameter trees have been shown to store disproportionally massive amounts of carbon compared to smaller trees, highlighting their importance in mitigating climate change, according to a new study in Frontiers in Forests and Global Change.

 They found that despite only accounting for 3% of the total number of trees on the studied plots, large trees stored 42% of the total above-ground carbon within these forest ecosystems. This study is among the first of its kind to report how a proposed policy could affect carbon storage in forest ecosystems, potentially weakening protections for large-diameter trees and contributing to huge releases of carbon dioxide to the atmosphere in the face of a changing climate.

Frontiers in Forests and Global Change, DOI: 10.3389/ffgc.2020.594274 , www.frontiersin.org/articles/1 … fgc.2020.594274/full

https://phys.org/news/2020-11-biggest-trees-capture-carbon-large.ht...

Comment by Dr. Krishna Kumari Challa on November 5, 2020 at 12:14pm

How Vaccines Train Innate Immunity

A recent study elucidates some of the changes that occur in the body after inoculation with a tuberculosis vaccine.

While researchers have observed for decades that certain vaccines seem to help recipients ward off more than just the target pathogen, only in recent years have they identified possible mechanisms for these bonus benefits. For example, in a study published this year (depicted here), researchers examined immune cells from the blood and bone marrow of healthy adults before and after they received a live tuberculosis vaccine known as bacille Calmette-Guérin, or BCG.

In the bone marrow post-vaccination, genes are expressed that trigger hematopoietic stem and progenitor cells to differentiate into monocytes, neutrophils, and other so-called myeloid cells. In a separate analysis of the effects of BCG in newborns, the researchers found that the vaccine ramped up the number of neutrophils in babies’ blood compared with unvaccinated infants.

Monocytes from the blood displayed epigenetic changes after vaccination that opened chromatin harboring multiple genes involved in driving an inflammatory response, making them more accessible for transcription. Meanwhile, chromatin closed around genes associated with immune tolerance.

When exposed to the fungal pathogen Candida albicans in vitro, immune cells sampled from patients’ blood 90 days after vaccination released more of the cytokine interleukin 1β, which mediates inflammation, than did cells from blood drawn from the same individuals before vaccination.

https://www.the-scientist.com/infographics/infographic-how-vaccines...

Comment by Dr. Krishna Kumari Challa on November 5, 2020 at 12:12pm

Yellow Turtle Found in India

For the second time in just three months the Indian Forest Service has announced the discovery of a golden flapshell turtle.

Like a slice of cheese, a slab of butter, or the yolk of an egg, this zesty creature with its vivid yellow shell, head, and limbs.

While such aberrations of colour are rare in nature, this bizarre phenomenon is more common than many recognise.

Yellow variants of the Indian flapshell turtle (Lissemys punctata) - which typically are brown with yellow spots and a creamy white underside - have been discovered a handful of times over the years in various parts of South Asia, where it is one of the most common aquatic turtle species.

The genetic anomaly doesn't happen often, but when it does, it tends to stand out.

https://www.sciencealert.com/what-s-the-deal-with-this-ridiculous-g...

Comment by Dr. Krishna Kumari Challa on November 5, 2020 at 12:02pm

**Scientists Find Tissue in The Human Eye That Appears Resistant to SARS-CoV-2

While this general advice is repeated by health authorities the world over, there's still a lot we don't know about how the coronavirus might enter the body through the eyes, although scientists suggest it's "biologically plausible".

However, new evidence suggests at least some of the eye may in fact be resistant to SARS-CoV-2 – even while it's susceptible to other kinds of viruses.

In a new study, researchers at Washington University in St. Louis found that the cornea – the transparent dome at the front of the eye, which covers the iris and pupil – appeared to be resistant to coronavirus infection in experiments, although they're eager to emphasise the findings are only preliminary.

These findings do not prove that all corneas are resistant

"But every donor cornea we tested was resistant to the novel coronavirus. It's still possible a subset of people may have corneas that support growth of the virus, but none of the corneas we studied supported growth of SARS-CoV-2."

In experiments using corneal tissue from 25 human donors and also mice corneas, the researchers exposed the eye tissue to three separate viruses: SARS-CoV-2, Zika virus, and herpes simplex virus 1 (HSV-1, which produces cold sores).

In the human cornea explants tested (which also contained some conjunctiva tissue, the membrane that covers the rest of the front of the eye), the experiment showed that herpes and Zika virus were able to replicate in the tissue – but tests showed no sign of SARS-CoV-2 replication.

"The cornea and conjunctiva are known to have receptors for the novel coronavirus, but in these  studies, researchers found that the virus did not replicate in the cornea.

A potential molecular inhibitor of viruses in the eye – called interferon lambda – was able to limit virus growth in the human cornea for HSV-1 and Zika virus, but blocking the protein didn't seem to boost SARS-CoV-2's ability to replicate.

Without more to go on, the researchers' best guess for now is that the human cornea's resistance to coronavirus is "likely regulated by a distinct antiviral pathway". Quite what that pathway is we still don't know, and the team says further study is needed to confirm these findings.

https://www.cell.com/cell-reports/fulltext/S2211-1247(20)31328-0?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2211124720313280%3Fshowall%3Dtrue

https://www.sciencealert.com/there-s-a-part-of-the-human-eye-that-s...

• ‹ Previous
• 1
• …
• 698
• 699
• 700
• 701
• 702
• …
• 1053
• Next ›
• Page