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Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 1:03pm

Random effects key to containing epidemics

To control an epidemic, authorities will often impose varying degrees of lockdown. In a paper in the journal Chaos, scientists have discovered, using mathematics and computer simulations, why dividing a large population into multiple subpopulations that do not intermix can help contain outbreaks without imposing contact restrictions within those local communities.

The key idea is that, at low infection numbers, fluctuations can alter the course of the epidemics significantly, even if you expect an exponential increase in infection numbers on average. 

When infection numbers are high, random effects can be ignored. But subdividing a population can create communities so small that the random effects matter.

When a large population is divided into smaller communities, these random effects completely change the dynamics of the full population. Randomness causes peak infection numbers to be brought way down.

"Stochastic effects on the dynamics of an epidemic due to population subdivision," Chaos (2020). DOI: 10.1063/5.0028972

https://phys.org/news/2020-10-random-effects-key-epidemics.html?utm...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 12:59pm

Asymptomatic virus sufferers lose antibodies sooner: study

Asymptomatic coronavirus sufferers appear to lose detectable antibodies sooner than people who have exhibited COVID-19 symptoms, according to one of the biggest studies of its kind

https://medicalxpress.com/news/2020-10-asymptomatic-virus-antibodie...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 12:43pm

Why do certain chemotherapies increase the likelihood of blood cancer?

One rare complication of cancer treatment is the development of a secondary blood cancer—therapy-related acute myeloid leukemia or myelodysplastic syndrome. These blood cancers are very aggressive and do not respond well to treatment. Historically, doctors thought that cancer treatments such as chemotherapy and radiation caused an accumulation of mutations in the blood that led to these therapy-related cancers.

In recent years, however, researchers have found that these mutations in the blood can also occur spontaneously with increasing age. This phenomenon is called clonal hematopoiesis (CH), and it's found in 10 to 20% of all people over age 70. The presence of CH increases the risk of developing a blood cancer. Using data from MSK-IMPACTTM, Memorial Sloan Kettering's clinical genomic sequencing test, researchers have shown that CH is also frequent in cancer patients.

Focusing on a subset of patients on whom they had more detailed data, the investigators observed increased rates of CH in people who had already received treatment. They made specific connections between cancer therapies such as radiation therapy and particular chemotherapies—for example certain platinum drugs or agents called topoisomerase II inhibitors—and the presence of CH.

Unlike the CH changes found in the general population, the team found that CH mutations after cancer treatment occur most frequently in the genes whose protein products protect the genome from damage. One of these genes is TP53, which is frequently referred to as "the guardian of the genome."

This finding provides a direct link between mutation type, specific therapies, and how these cells progress towards becoming a blood cancer.

 Kelly L. Bolton et al. Cancer therapy shapes the fitness landscape of clonal hematopoiesis, Nature Genetics (2020). DOI: 10.1038/s41588-020-00710-0

https://medicalxpress.com/news/2020-10-chemotherapies-likelihood-bl...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 12:36pm

Vampire bats social distance when they get sick

 Wild vampire bats that are sick spend less time near others from their community, which slows how quickly a disease will spread.

As a pathogen spreads across a population, changes in social behaviour can alter how the disease spreads. Transmission rates can increase when parasites change host behaviour or decrease when healthy individuals avoid sick ones. In certain social insects, sick ones might self-isolate voluntarily or be excluded by their colony mates. A simpler mechanism causing reduced transmission is that infected animals often show sickness behaviour, which includes increased lethargy and sleep, and reduced movement and sociality. This sickness-induced social distancing does not require cooperation from others and is probably common across species.

 "Tracking sickness effects on social encounters via continuous proximity-sensing in wild vampire bats" Behavioral Ecology (2020). DOI: 10.1093/beheco/araa111

https://phys.org/news/2020-10-vampire-social-distance-sick.html?utm...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 12:33pm

The experimental demonstration of entanglement between mechanical and spin systems

Quantum entanglement is the basic phenomenon underlying the functioning of a variety of quantum systems, including quantum communication, quantum sensing and quantum computing tools. This phenomenon results from an interaction (i.e., entanglement) between particles. Attaining entanglement between distant and very different objects has  proved highly challenging till now.

Researchers  have recently generated entanglement between a mechanical oscillator and a collective atomic spin oscillator. Their work introduces a strategy for generating entanglement between these two distinct systems.

To generate entanglement between a mechanical and a spin system, Polzik and his colleagues leveraged a key feature of spin oscillators, namely that they can have an effective negative mass. When it is excited, a spin oscillator's energy is reduced, which allows it to become entangled with a more conventional mechanical oscillator that has a positive mass. The researchers experimentally generated this entanglement by performing a joint measurement on both oscillators.

Entanglement between distant macroscopic mechanical and spin systems. Nature Physics (2020). DOI: 10.1038/s41567-020-1031-5.

https://phys.org/news/2020-10-experimental-entanglement-mechanical....

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 12:11pm

Scientists develop genetic 'monitors' that detect when genes are active
Genetic sensors that can detect the activity from genes, rather than just the genes themselves, have been developed by a team of scientists.

Based on the CRISPR gene editing system, the scientists have developed microscopic machines that use these sensors to detect when genes are ‘on’ or ‘off’ inside a cell, and react to those changes dynamically - making them a potentially ideal monitoring system.

These genetic sensors are detailed in a new paper published in The CRISPR Journal, where the scientists demonstrate a genetic device based on the CRISPR system inside a bacterial cell. The work is the first step in scientists developing genetic devices that can make changes to gene expression after sensing the existing gene activity within a cell.

Cells contain a number of genes that are expressed to perform numerous functions, from sensing their environment and processing food. By having a sensor that can detect when those genes are active, scientists could program a machine to react to a specific process, such as when the cell digests its food.

To generate these novel genetic devices, the scientists used as a scaffold the programmable part of CRISPR which is also responsible for sequence recognition and binding, called guide RNA sequence (gRNA). They were able to redesign the gRNA sequence by introducing in it a sensor so that the CRISPR complex would be able to bind the DNA target only after being activated by a trigger signal, such as short segments of viral RNA sequences. The sensor can be triggered by any chosen RNA sequence and in this way it activates a CRISPR system at any point of the life cycle of a cell or virus.

https://warwick.ac.uk/newsandevents/pressreleases/scientists_develo...

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 11:57am

COVID-19

Get the latest information from the MoHFW about COVID-19.

Neuropilin-1 drives SARS-CoV-2 infectivity

Comment by Dr. Krishna Kumari Challa on October 28, 2020 at 11:38am

New COVID-19 related genes are helpful and harmful, found in massive screen

Researchers at Yale University and the Broad Institute of MIT and Harvard screened hundreds of millions of cells exposed to the COVID-19 and MERS viruses and identified dozens of genes that both enable the viruses to replicate in cells and also those that seem to slam the door on the virus.

The pro-viral and anti-viral role of these genes will help guide scientists in development of new therapies to combat COVID-19, the researchers say.

The findings were reported Oct. 26 in the journal Cell.

Scientists have previously identified how the SARS-CoV-2 coronovirus, which causes COVID-19, attaches to and invades cells, but less is known about why some cells are more susceptible to infection. Understanding the genetics behind the host cells’ susceptibility to infection may help explain why some people exposed to the virus experience few or no symptoms and others become extremely ill or die.

https://news.yale.edu/2020/10/26/new-covid-19-related-genes-helpful...

Comment by Dr. Krishna Kumari Challa on October 20, 2020 at 9:57am

Vocal discrimination of African lions and its potential for collar-free tracking

Comment by Dr. Krishna Kumari Challa on October 20, 2020 at 9:53am

Scientists discover the unique signature of a lion's roar using machine learning

The roar of a lion is one of the most thrilling and captivating sounds of the wild. This characteristic call is typically delivered in a bout consisting of one or two soft moans followed by several loud, full-throated roars and a terminating sequence of grunts.

A team of scientists based in WildCRU at the University of Oxford, well-known for their research involving Cecil the Lion, has teamed up with colleagues in the Department of Computer Science to discover the precise ways in which each lion’s roar is distinct, identifiable and trackable.

Harnessing new machine learning techniques, the group designed a device, known as a biologger, which can be attached to an existing lion GPS collar to record audio and movement data. The biologgers allow the scientists to confidently associate each roar with the correct lion by cross-referencing movement and audio data through the large datasets of roar recordings collected.

With the data collected by the biologgers, the scientists trained a pattern recognition algorithm to “learn” each individual’s roars and then tested the algorithm on sequences that it had not seen before to determine whether the shape of the contour as a whole is an important distinguishing feature.

Results, published in Bioacoustics, reveal that it is possible to classify roars according to individual identity with 91.5% accuracy. These findings suggest that the overall shape of the fundamental frequency (f0) of the full-throated roar contour is consistent within each individuals’ roars and sufficiently different from other individuals to allow for accurate classification of individual identity.

Previous research has shown that lions can recognise the calls of other individuals, allowing them to locate distant companions and also to avoid potentially hostile neighbours. These new findings reveal a possible mechanism for individual vocal recognition amongst African lions. They indicate that individual lions may be able to learn the subtle variations in the fundamental frequency of other lions’ roars and thereby associate particular variations with particular identities.

https://www.ox.ac.uk/news/2020-10-13-scientists-discover-unique-sig...

https://researchnews.cc/news/3114/Scientists-discover-the-unique-si...

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