Comment

Comment by Dr. Krishna Kumari Challa on October 1, 2020 at 9:16am

Gene expression altered by direction of forces acting on cell

Tissues and cells in the human body are subjected to a constant push and pull – strained by other cells, blood pressure and fluid flow, to name a few. The type and direction of the force on a cell alters gene expression by stretching different regions of DNA, researchers found in a new study.

The findings could provide insights into physiology and diseases such as fibrosis, cardiovascular disease and malignant cancer, the researchers said.

Force is everywhere in the human body, and both external and internal forces can influence your body far more than you may have thought. These strains profoundly influence cellular behaviours and physiological functions, which are initiated at the level of gene expression.

They found that the force from the magnetic bead caused a rapid increase in expression for certain genes, but the amount of the increase depended on the direction the bead moved. When the bead rolled along the long axis of the cell, the increase was the lowest, but when the force was applied perpendicularly – across the short axis of the cell – gene activity increased the most. When the bead was moved at a 45-degree angle or rotated in the same plane as the cell to induce shear stress, the response was intermediate.
These observations show that gene upregulation and activation are very sensitive to the mode of the applied force, when the magnitude of the force remains unchanged.

In further experiments, the researchers found that the reason for the difference lies in the method that the forces are relayed to the cell’s nucleus, where DNA is housed. Cells have a network of support structures called the cytoskeleton, and the main force-bearing elements are long fibers of the protein actin. When they bend due to a force, they relay that force to the nucleus and stretch the chromosomes.

These actin fibers run lengthwise along the cell. So when the force strains them widthwise, they deform more, stretching the chromosomes more and causing greater gene activity, the researchers found.

https://news.illinois.edu/view/6367/385931150

Comment by Dr. Krishna Kumari Challa on October 1, 2020 at 8:55am

Pregnancy Loss: A possible link between olfaction and miscarriage

Unexplained repeated pregnancy loss is associated with an altered perception of male odors and differences in brain regions that process smells.

Exposing female rodents to the smell of adult males can lead to synchronized menstrual cycling  and accelerated sexual maturation, as well as to embryos failing to implant in the uterus . Olfactory cues might also play a role in human reproduction: for instance, the menstrual cycle phase may influence preferences for male odors . This presents the possibility that altered neural processing of socially relevant odors, such as the scent of a partner, may be linked to pregnancy loss and other reproductive disorders. Now researchers report that women who have experienced unexplained repeated pregnancy loss process the odors of males differently.

https://elifesciences.org/articles/62534?utm_source=content_alert&a...

Comment by Dr. Krishna Kumari Challa on October 1, 2020 at 8:39am

India pushes bold ‘one nation, one subscription’ journal-access plan

Researchers will also recommend an open-access policy that promotes research being shared in online repositories.The Indian government is pushing a bold proposal that would make scholarly literature accessible for free to everyone in the country. The government wants to negotiate with the world’s biggest scientific publishers to set up nationwide subscriptions, rather than many agreements with individual institutions that only scholars can use, say researchers consulting for the government.

The proposal is expected to be part of the government’s latest science, technology and innovation policy.

If successful, India would become the largest country to strike deals that give access to paywalled articles to all citizens — more than 1.3 billion people — say researchers.

https://www.nature.com/articles/d41586-020-02708-4

Comment by Dr. Krishna Kumari Challa on October 1, 2020 at 7:10am

Dinosaur feather study debunked: Overwhelming evidence supports Jurassic fossil does belong to Archaeopteryx

A new study provides substantial evidence that the first fossil feather ever to be discovered does belong to the iconic Archaeopteryx, a bird-like dinosaur named in Germany on this day in 1861. This debunks a recent theory that the fossil feather originated from a different species.

The new research finds that the Jurassic fossil matches a type of wing feather called a primary covert. Primary coverts overlay the primary feathers and help propel birds through the air. Researchers analyzed nine attributes of the feather, particularly the long quill, along with data from modern birds. They also examined the 13 known skeletal fossils of Archaeopteryx, three of which contain well-preserved primary coverts. The researchers discovered that the top surface of an Archaeopteryx wing has primary coverts that are identical to the isolated feather in size and shape. The isolated feather was also from the same fossil site as four skeletons of Archaeopteryx, confirming their findings.

Through scientific detective work that combined new techniques with old fossils and literature, scientists were able to finally solve these centuries-old mysteries.

Using a specialized type of electron microscope, the researchers determined that the feather came from the left wing. They also detected melanosomes, which are microscopic pigment structures. After refining their color reconstruction, they found that the feather  was entirely matte black, not black and white as another study has claimed.

Evidence corroborates identity of isolated fossil feather as a wing covert of Archaeopteryx, Scientific Reports (2020). doi.org/10.1038/s41598-020-65336-y

https://phys.org/news/2020-09-dinosaur-feather-debunked-overwhelmin...

Comment by Dr. Krishna Kumari Challa on October 1, 2020 at 6:12am

Mutations that affect aging: More common than we thought?

The number of mutations that can contribute to aging may be significantly higher than previously believed, according to new research on fruit flies. 

Many functions of our bodies deteriorate slowly but surely as we age, and eventually an organism dies. This thought may not be very encouraging, but most of us have probably accepted that this is the fate of all living creatures—death is part of life. However, those who study evolutionary biology find it far from clear why this is the case. The evolution of aging is, in a manner of speaking, a paradox. Evolution causes continuous adaptation in organisms, but even so it has not resulted in them ceasing to age.

Nearly 70 years ago, evolutionary biologists proposed two theories concerning two different types of mutation that contribute to aging. Both of these mutations have a detrimental effect as the organism becomes older—which leads to aging—while they are either advantageous or neutral early in life. Researchers have, however, not been able to determine which of the two types of mutation contributes most to aging, despite experimental studies.

A new theory was proposed a few years ago suggesting that aging is caused by mutations with a detrimental effect early in life, and whose negative effects increase with age. Those who support this hypothesis believe that many of the mutations that arise have negative effects right from the start, compared with the normal variant of a gene.

The study now published describes experiments to test the theory of mutations that have a detrimental effect throughout life and contribute to aging. The authors used one of the most well-studied animals in the world, namely the fruit fly, or Drosophila melanogaster. They tested 20 different mutations that they had placed into the genetic material of the flies. For each individual mutation, they studied a group of flies with the mutation and a control group without it. Each mutation had a specific, visible effect, which made it easy to follow, such as a somewhat different appearance of the wings or a different shape of the eyes.

As an organism ages, the probability that an individual dies increases, and its ability to reproduce falls. The researchers determined the fertility of the fruit flies and used it as a measure of aging. They counted the number of eggs laid by each female early in life, after two weeks, and finally after a further two weeks (which is a ripe old age for a fruit fly!). The researchers wanted to see whether the difference between flies with the mutations and the control group changed as they aged. The results support the theory they were testing. Most of the mutations had a negative effect on the fertility of the fruit flies early in life, and most of them also caused reproductive aging to occur more rapidly.

The results suggest that mutations that are detrimental early in life can also contribute to aging. Thus it may be that mutations that bring on aging are significantly more common than we previously thought.

 "Deleterious mutations show increasing negative effects with age in Drosophila melanogaster", Martin I. Brengdahl, Christopher M. Kimber, Phoebe Elias, Josephine Thompson and Urban Friberg, (2020), BMC Biology, published online 30 September, DOI: 10.1186/s12915-020-00858-5

https://phys.org/news/2020-09-mutations-affect-aging-common-thought...

Comment by Dr. Krishna Kumari Challa on October 1, 2020 at 6:00am

Achieving invisibility: Cross-wavelength invisibility integrated with invisibility tactics

Using biomimicry - the natural ecological relationship between transparent oceanic animals and their predators that employ a cross-wavelength detection strategy - proposed a new concept of cross-wavelength invisibility that integrated a variety of invisibility tactics. They presented a Boolean metamaterial design strategy to balance divergent material requirements across cross-scale wavelengths. As proof of concept, they simultaneously demonstrated longwave cloaking and shortwave transparency using a nanoimprinting technique. The work extended stealth techniques from individual strategies of invisibility targeting a single-wavelength spectrum to integrated invisibility targeting cross-wavelength applications. These experiments will pave the way to develop cross-wavelength integrated metadevices.

The new strategy complements existing mainstream strategies of chameleon-like adaptive camouflage and the wave-bypassing invisibility cloak.  In this work, scientists break the existing ecological relationship by attempting to hide the transparent prey from the cross-spectral vision of their predators. As a result, this philosophy of invisibility will be of significance for practical stealth technologies.

Xu S. et al. Cross-wavelength invisibility integrated with various invisibility tactics, Science Advances, 10.1126/sciadv.abb3755

Ni X. et al. An ultrathin invisibility skin cloak for visible light, Science, 10.1126/science.aac9411

Landy N. et al. A full-parameter unidirectional metamaterial cloak for microwaves. Nature Materials, doi.org/10.1038/nmat3476

https://phys.org/news/2020-09-invisibility-cross-wavelength-tactics...

Comment by Dr. Krishna Kumari Challa on October 1, 2020 at 5:50am

3-D printed 'invisible' fibers can sense breath, sound, and biological cells

From capturing your breath to guiding biological cell movements, 3-D printing of tiny, transparent conducting fibers could be used to make devices which can 'smell, hear and touch'—making it particularly useful for health monitoring, Internet of Things and biosensing applications.

Researchers used 3-D printing, also known as additive manufacturing, techniques to make electronic fibers, each 100 times thinner than a human hair, creating sensors beyond the capabilities of conventional film-based devices.

The fiber printing technique can be used to make non-contact, wearable, portable respiratory sensors. These printed sensors are high-sensitivity, low-cost and can be attached to a mobile phone to collect breath pattern information, sound and images at the same time.

"Inflight fiber printing toward array and 3D optoelectronic and sensing architectures" Science Advances (2020). DOI: 10.1126/sciadv.abd1882 , advances.sciencemag.org/lookup … .1126/sciadv.aba0931

https://techxplore.com/news/2020-09-d-invisible-fibers-biological-c...

Comment by Dr. Krishna Kumari Challa on September 30, 2020 at 10:15am

A Strong & Transparent Alternative To Plastic Instead of non-biodegradable plastic, your next ‘plastic’ bag could be made out of bacterial biofilms. 

Researchers in China have used bacteria to make an ultra-strong and transparent film that can replace plastic .

Although most plastic films—such as plastic bags and food wrappers—have a lifespan of mere minutes to hours, they persist in the environment for hundreds of years. Furthermore, exposure to sunlight, wind and wave action can cause a single plastic bag to be broken up into as many as 1.75 million microscopic fragments. These so-called microplastics have been found in every corner of the globe from Mount Everest to the Mariana Trench. Worryingly, they have been found in more than 100 species, including, fish, shrimp and birds. To reduce the use of plastic, a team led by Professor Yu Shuhong from the University of Science and Technology of China (USTC) has developed a nanocomposite film inspired by mother of pearl that could one day replace many single-use plastics. The researchers first allowed a thin layer of Gluconacetobacter xylinus bacteria to grow on an agar plate before spraying on a layer of nano-clay. The nano-clay particles became entangled in the cellulose nanofibers secreted by the bacteria, forming a uniform hydrogel. Multiple layers of this hydrogel were then pressed together to form a dense composite film that showed a ‘brick and fibre’ structure found in nacre. When they tested the properties of the resulting film, the researchers found that it had a transmittance and haze of more than 73 percent and 80 percent respectively, suggesting that it could be useful for managing light in optoelectronic devices. The film was six times stronger than PET film and three times as stiff. It also was flexible enough to be folded and yet show no visible damage after unfolding. 

Guan et al. (2020) Nanocomposite Films for Plastic Substitute. https://linkinghub.elsevier.com/retrieve/pii/S2590238520303726

https://www.cell.com/matter/fulltext/S2590-2385(20)30372-6?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2590238520303726%3Fshowall%3Dtrue

https://www.asianscientist.com/2020/09/in-the-lab/bacteria-plastic-...

Comment by Dr. Krishna Kumari Challa on September 30, 2020 at 10:11am

Combating Superbugs Through Comic Books 

https://www.asianscientist.com/2020/09/features/asias-changemakers-...

--

A brief history of Quantum mechanics

Comment by Dr. Krishna Kumari Challa on September 30, 2020 at 9:36am

Water on Mars: discovery of three buried lakes intrigues scientists

Researchers have detected a group of lakes hidden under the red planet’s icy surface.

https://www.nature.com/articles/d41586-020-02751-1?utm_source=Natur...

• ‹ Previous
• 1
• …
• 817
• 818
• 819
• 820
• 821
• …
• 1148
• Next ›
• Page