Comment

Comment by Dr. Krishna Kumari Challa on January 10, 2021 at 9:28am

The Riemann Hypothesis, Explained

Comment by Dr. Krishna Kumari Challa on January 7, 2021 at 12:40pm

Quicksand Science: Why It Traps, How to Escape

If stumbling into quicksand ranks on your list of worries, don't panic. A new study suggests that quicksand is not as deadly as it may seem.

https://www.nationalgeographic.com/news/2005/9/quicksand-science-wh...

Comment by Dr. Krishna Kumari Challa on January 7, 2021 at 9:29am

How Earth's oddest mammal got to be so bizarre

Often considered the world's oddest mammal, Australia's beaver-like, duck-billed platypus exhibits an array of bizarre characteristics: it lays eggs instead of giving birth to live babies, sweats milk, has venomous spurs and is even equipped with 10 sex chromosomes. Now, an international team of researchers led by University of Copenhagen has conducted a unique mapping of the platypus genome and found answers regarding the origins of a few of its stranger features.

--

It lays eggs, but nurses, it is toothless, has a venomous spur, has webbed feet, fur that glows and has 10 sex chromosomes.

The complete genome has provided us with the answers to how a few of the platypus' bizarre features emerged. At the same time, decoding the genome for platypus is important for improving our understanding of how other mammals evolved—including us humans. It holds the key as to why we and other eutheria mammals evolved to become animals that give birth to live young instead of egg-laying animals.

Yang Zhou et al. Platypus and echidna genomes reveal mammalian biology and evolution, Nature (2021). DOI: 10.1038/s41586-020-03039-0

Paula Spaeth Anich et al. Biofluorescence in the platypus (Ornithorhynchus anatinus), Mammalia (2020). DOI: 10.1515/mammalia-2020-0027

https://phys.org/news/2021-01-earth-oddest-mammal-bizarre.html?utm_...

**

Comment by Dr. Krishna Kumari Challa on January 7, 2021 at 9:22am

How an embryo tells time

It is estimated that the majority of pregnancies that fail do so within the first seven days after fertilization, before the embryo implants into the uterus. In this time period, a complicated cascade of events occurs with precise timing. One particularly important process is called polarization, when the individual cells that make up the embryo become asymmetrical. Polarization occurs at 2.5 days for mouse embryos and 3.5 days for human embryos.

Just as musicians playing together in an orchestra need to play at the right time—not early, not late—the timing of polarization is critical for proper embryonic function. Studies have shown that if polarization occurs too early or too late, the embryo is less likely to develop properly. Embryos obviously cannot look at a clock to know when it is time to polarize, so how do they "know" when it is time?

A new study has uncovered the signals that mouse embryos follow to initiate polarization. Understanding the molecular mechanisms underlying embryonic development is critical for understanding how life begins.

The first is the zygotic genome activation, or ZGA, which represents the initial "awakening" of the embryonic DNA after it has combined from sperm and egg, with certain genes for development flipped on like a dormant computer booting up. A flood of molecular activity follows ZGA, and during that period, the team found, three specific factors—protein-based structures called Tfap2c, Tead4, and RhoA—work together to initiate polarization.

This research is the first to identify the necessary and sufficient conditions that drive cell polarization. Once the team had identified the three factors that initiate polarization, they turned their focus to the polarization process itself.

 Meng Zhu et al. Developmental clock and mechanism of de novo polarization of the mouse embryo, Science (2020). DOI: 10.1126/science.abd2703

https://phys.org/news/2021-01-embryo.html?utm_source=nwletter&u...

Comment by Dr. Krishna Kumari Challa on January 7, 2021 at 8:40am

Proteins engineered to form honeycomb structures can block uptake of receptors from the surface of cells

A new class of protein material that interacts with living cells without being absorbed by them can influence cell signaling, a new study shows. The material does this by binding and sequestering cell surface receptors.

The discovery could have far-reaching implications for stem cell research and enable the development of new materials designed to modulate the behavior of living systems.

Cells interact with their environment via receptors at their surface. These receptors can bind to hormones, neurotransmitters, drugs, and toxins. When such molecules bind to a receptor, this triggers a response inside the cell, a process known as signaling.

But for the cell, it is important that this response be transient, to still be responsive to the signal later on. To achieve this, cells will commonly terminate signaling by absorbing both an activated receptor and the molecule that stimulated it, thereby targeting both for destruction inside the cell.

"This tendency of cells to internalize receptors likely lowers the efficiency of immunotherapies. Indeed, when antibody drugs bind their target receptors and then become internalized and degraded, more antibody must always be injected.

To create a way around this, researchers now designed new proteins that assemble into large, flat patches. This molecular scaffolding was then further engineered to contain signaling molecules. They showed that such protein materials could latch onto cells, activate surface receptors, and resist being absorbed by the cell for hours or even days.

This work paves the way towards a synthetic cell biology, where a new generation of multi-protein materials can be designed to control the complex behavior of cells.

Design of biologically active binary protein 2D materials, Nature (2021). DOI: 10.1038/s41586-020-03120-8 , www.nature.com/articles/s41586-020-03120-8

https://phys.org/news/2021-01-proteins-honeycomb-block-uptake-recep...

Comment by Dr. Krishna Kumari Challa on January 7, 2021 at 8:34am

Study explores the effects of immune responses on the aging brain

As human beings age, the functioning of organs gradually deteriorates. While countless past studies have investigated the effects of aging on the human body, brain and on cognition, the neural mechanisms and environmental factors that can accelerate or slow down these effects are not yet fully understood.

The immune system and the nervous system are both known to play a key role in the control of organs in the body. Moreover, past findings suggest that both of these systems change significantly during aging.

Neuroscientific studies have found that as the nervous system ages, the way in which the human body controls immune responses also changes. Nonetheless, how the nervous system's aging process affects immune responses and the consequent impact on the brain's functioning are still poorly understood.

Researchers have recently carried out a study investigating the possible effects of immune responses on the aging brain. Their paper, published in Nature Neuroscience, shows that the deterioration of neuroblasts (i.e., the embryonic cells  from which nerve fibers originate) in the aging brain can increase the toxicity of natural killer cells (NK), which leads to impairments in neurogenesis and cognition. NK cells are a class of blood cells that are part of the human immune system.

"Systemic inflammation escalates during the aging process, but the potential impact of immune and inflammatory responses on brain aging remains unknown.

Researchers now found that immune cells such as NK cells impair neurogenesis and cognitive function during normal brain aging. Immune modulation targeting immune cells (which accumulate in the aged brain) may thus be useful to improve cognition in the aged population.

The recent study carried out by this team of researchers suggests that the accumulation of NK cells in the aging brain can impair the process through which neurons are formed in the brain, known as neurogenesis. In the future, this important finding could inform the development of more effective treatment strategies for improving cognition in older adults.

Neuroblast senescence in the aged brain augments natural killer cell cytotoxicity leading to impaired neurogenesis and cognition. Nature Neuroscience(2020). DOI: 10.1038/s41593-020-00745-w

https://medicalxpress.com/news/2021-01-explores-effects-immune-resp...

Comment by Dr. Krishna Kumari Challa on January 6, 2021 at 11:43am

Removing Two Pollutants With One Bacteria A new strain of bacteria that can remove both nitrogen and phosphorus from sewage could reduce the electricity consumption of treatment plants by over 60 percent. 

A newly identified strain of bacteria that can simultaneously remove both nitrogen and phosphorus from sewage could make wastewater treatment simpler, cheaper and greener. 

Called SND5, the bacteria also circumvents the problem of nitrous oxide gas release by converting ammonia into harmless nitrogen gas instead. The unique strain was discovered in a wastewater treatment plant in Singapore. When the NUS research team was carrying out routine monitoring, they observed an unexpected removal of nitrogen in the aerobic tanks, as well as better-than-expected phosphate removal despite the absence of known phosphorus-removing bacteria. The researchers then took wastewater samples from a tank, isolated various strains of bacteria and tested each of them for their ability to remove nitrogen and phosphorus. One of the strains, which appeared as sticky, creamy, light yellow blobs on the agar medium, surprised the researchers by its ability to remove both nitrogen and phosphorous from water. In fact, it did the job faster than the other microbes that were tested. The team sequenced its genes and compared them to related bacteria in a global database, establishing it to be a new strain. Compared to conventional nitrogen removal processes of nitrification and denitrification, the lower oxygen demand of the newly identified microbe could help reduce electricity consumption at wastewater treatment plants by about 62 percent.

 Wang & He (2020) Complete Nitrogen Removal via Simultaneous Nitrification and Denitrification by a Novel Phosphate Accumulating Thauera sp. Strain SND5.

https://www.sciencedirect.com/science/article/abs/pii/S004313542030...

https://linkinghub.elsevier.com/retrieve/pii/S0043135420308368

https://www.asianscientist.com/2020/12/in-the-lab/thauera-snd5-nitr...

Comment by Dr. Krishna Kumari Challa on January 6, 2021 at 10:56am

SETI: new signal excites alien hunters – here’s how we could find out if it’s real

https://theconversation.com/seti-new-signal-excites-alien-hunters-h...

Comment by Dr. Krishna Kumari Challa on January 6, 2021 at 10:08am

**Researchers uncover unequal effects of human activity on mammals

Silvia Pineda-Munoz et al. Mammal species occupy different climates following the expansion of human impacts, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.1922859118

https://phys.org/news/2021-01-uncover-unequal-effects-human-mammals...

--

Uncovering how grasslands changed our climate

Grasslands are managed worldwide to support livestock production, while remaining natural or semi-natural ones provide critical services that contribute to the wellbeing of both people and the planet. Human activities are, however, causing grasslands to become a source of greenhouse gas emissions rather than a carbon sink. A new study published in Nature Communications reports how grasslands used by humans have changed our climate in recent centuries.

--

Heat treatment may make chemotherapy more effective

Heating up cancer cells while targeting them with chemotherapy is a highly effective way of killing them, according to a new study led by UCL researchers.

Comment by Dr. Krishna Kumari Challa on January 6, 2021 at 9:46am

Wood-inspired cement with high strength and multifunctionality

Scientists in advanced materials, engineering and science in China developed bio-inspired new cement materials based on unidirectionally porous architectures to replicate the designs of natural wood. The resulting wood-like cement material showed higher strength at equal densities, alongside multifunctional properties for effective thermal insulation, water permeability and easy adjustment for water repulsion. The team simultaneously achieved high strength and multifunctionality to make the wood-like cement a promising new building material for wood-mimetic designs with high performance. They presented a simple fabrication procedure to promote better efficiency during mass production with applications suited across other material systems.

Porous cement-based materials possess low thermal conductivity for heat insulation, high sound-absorbing efficiency, outstanding permeability for air and water, while maintaining light weight and fire resistance. However, it still remains a key challenge to achieve the simultaneous enhancement of both mechanical and multifunctional properties including mechanical support, effective transport and good thermal insulation. It is therefore highly desirable to generate materials with enhanced mechanical and multifunctional properties to actively implement the design principles of natural wood. During the experiments, Wang et al. developed wood-like cement with unidirectionally porous architectures formed via a bidirectional freezing treatment method. The process allowed bridges to form between the constituents of the structure, the team then thawed the fully frozen bodies until the ice gradually melted and the cement hardened. The subsequent hydration process produced new minerals and gels within the cement, including hexagon-shaped calcium hydroxide, needle‐like ettringite and calcium-silicate-hydrate gels. The phases mainly originated at the cement lamellae and grew into their spacing during the thawing and curing process for better structural integrity with enhanced lamellae interconnections during porous cement formation. Using X-ray tomography (XRT), the team then revealed the formation of unidirectional micropores in the ice-templated cement.

Wang F. et al. Wood‐Inspired Cement with High Strength and Multifunctionality, Advanced Science, doi: doi.org/10.1002/advs.202000096

Monteiro P. et al. Towards sustainable concrete, Nature Materials, doi.org/10.1038/nmat4930

Roy D. M. New Strong Cement Materials: Chemically Bonded Ceramics, Science, 10.1126/science.235.4789.651

https://phys.org/news/2021-01-wood-inspired-cement-high-strength-mu...

• ‹ Previous
• 1
• …
• 667
• 668
• 669
• 670
• 671
• …
• 1054
• Next ›
• Page