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Comment by Dr. Krishna Kumari Challa on September 13, 2021 at 7:58am

How Old Are Stars? An  Astrophysicist Unlocks the Secrets of Age-Dating

Comment by Dr. Krishna Kumari Challa on September 13, 2021 at 7:52am

Researchers  discover river of dust around the sun

A team of researchers has discovered a dusty mystery in a newly explored region around Earth’s sun.  They noticed a new and unexplained stream of microscopic particles that seemed to be spraying out from around the star.

Dust can come from asteroids and comets or can be left over from the original formation of the planets. It can show us how our solar system has formed and continues to evolve and even how other solar systems may be evolving.

There are two basic types of dust around the sun. Dust that is in bound orbits around the sun that will eventually spiral into the sun. Then there’s unbound dust that is flung away and out of the solar system.

No one had seen anything like this third type before—dust flying away from the sun usually spreads out in every direction. It doesn’t tend to cluster together like this one. 

https://iopscience.iop.org/article/10.3847/PSJ/ac0bb9

https://researchnews.cc/news/8866/Researchers-led-by-undergraduate-...

Comment by Dr. Krishna Kumari Challa on September 12, 2021 at 12:54pm

Moreover, because microneedles are a dry formulation, they allow drugs to maintain their activity even without storing them at the low temperatures required of many injectable vaccines. For example, one study has shown that a vaccine for influenza can be stable for six months at 25 °C and at least a few weeks at 40 °C if incorporated into microneedles. This is critical for ensuring vaccinations reach far-flung corners of the world that do not have the resources to maintain the cold chain. 

Another issue is vaccine wastage. For example, in some cases only a portion of the dose is used before a vaccine expires. It can also happen that healthcare personnel decide not to vaccinate a patient when there are not enough patients to use the whole vial. According to estimates, the wastage rates for 10-dose vials may be as high as 25 percent for liquid vaccines and 40 percent for freeze-dried vaccines. With microneedle patches, there is no wasted drug. And there are no needles that require special disposal procedures.

There are plenty of hurdles yet to be overcome. We need further clinical studies in human volunteers to demonstrate safety and efficacy of this vaccine approach, and the scale-up of production is still in its infancy. On a lab scale, usually we fill molds with the polymer solutions via vacuum or centrifugation. Once dried, the final formulation is demolded and secured to a backing. This is tedious and not practical for mass production.

Additionally, the majority of vaccinations are sterilized by filtering, which is not feasible for solid microneedle patches. While the solution may be sterilized before being placed in the molds, the final product will also need to undergo sterilization by some alternative technique not yet developed. 

The recent pandemic and the possibility of others is a wake-up call to focus on these challenges. In the last year and a half, several institutions and biotech companies announced preclinical studies for a SARS-CoV-2 vaccine utilizing microneedle patches. Big pharmaceutical companies will certainly step up and invest more over the coming years in microneedle-based products. Injections have been used for centuries, but the necessity for a worldwide immunization effort is a persuasive reason to try to move forward. 

https://www.the-scientist.com/news-opinion/opinion-an-alternative-t...

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Comment by Dr. Krishna Kumari Challa on September 12, 2021 at 12:54pm

Comment by Dr. Krishna Kumari Challa on September 12, 2021 at 12:54pm

An Alternative to Injection

Research on microneedle patches for vaccine delivery has grown in popularity in recent years, due to their exceptional compliance and low invasiveness.

Several researchers, including ourselves, are working on a technology that aims to provide the advantages of injectable vaccines without the drawbacks—and without the traditional needle stick: microneedles. While the technology still has a long road to the clinic, having entered human trials less than 10 years ago, we believe this it is the future of vaccine delivery, and the ongoing pandemic has highlighted the need to accelerate its development.

Basically, an array of tiny needles measuring just hundreds of microns is attached to a backing, permitting bandage-like application. Drugs can be encapsulated within water-soluble microneedles that dissolve when the patch is placed on the skin, allowing the drug to be released. Importantly, the microneedles pierce the outermost layer of tissue to allow greater absorption of the drugs compared to creams or other kinds of medical patches such as nicotine patches, but they do not penetrate deep enough to stimulate pain receptors. The patch can be self-administered and is as easy and painless as taking a pill. 

The patch has its limitations. Being such a small medical device, for example, the maximum drug dose is less than 1 mg. But for treatments that do not require a high dosage, including vaccines (both antigen-based ones and nanoparticle ones, such as those used for mRNA vaccines against COVID-19), hormones, and drugs with elevated potency, microneedles are ideal. In addition to being user friendly, microneedles could elicit a more robust immunological response. 

Conventional vaccine injection bypasses the skin’s immune system and introduces the antigen into the muscle or subcutaneous tissue, thereby inducing a systemic immune response. Yet, the skin, our biggest organ, also has a superb immunogenicity capacity due to the presence of many antigen-presenting cells. By delivering antigens there, microneedles could capitalize on this local response to boost the protection provided by vaccines. Indeed, animal studies suggest that microneedles elicit higher antibody production and better cellular response.

part 1

Comment by Dr. Krishna Kumari Challa on September 12, 2021 at 12:38pm

Cannibalistic butterflies chow down on live caterpillars

For the first time, milkweed butterflies have been seen harassing, subduing and then slurping up the juices of caterpillars.

We generally think of butterflies s as beautiful, harmless, nectar-drinking insects. But new research carried out by the University of Sydney may change all that, as milkweed butterflies have been spotted scratching at caterpillars with their sharp claws to suck up their juices.

Milkweed butterflies are a group of butterflies in the Nymphalidae family, with one well-known species being the monarch butterfly.

As caterpillars, milkweed butterflies feed on toxic plants, using the chemicals as self-defence to make them unpalatable to birds and other predators. When the caterpillars turn into butterflies, they retain these toxins and advertise that they are poisonous with their bright colours.

Male butterflies will also use these toxic substances to produce mating pheromones. In order to boost their supplies of these love drugs, they’ll seek out extra sources of the chemicals.

Generally, they get these through plants, but in North Sulawesi, Indonesia, they have developed a taste for caterpillars – and they don’t care whether they are alive or dead.

“This is the first time the behaviour has been reported.

https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecy.3532

https://www.sciencefocus.com/news/cannibalistic-butterflies-chow-do...

Comment by Dr. Krishna Kumari Challa on September 11, 2021 at 12:02pm

Animals shape shifting as climate warms

Some animals are "shape-shifting" and have developed bigger tails, beaks and ears to regulate their body temperatures as the planet warms, according to a new study. From Australian parrots to European rabbits, researchers found evidence that a host of warm-blooded animals have evolved bigger body parts, which could allow them to lose body heat more effectively. Climate change is heaping "a whole lot of pressure" on animals. It's high time we recognised that animals also have to adapt to these changes, but this is occurring over a far shorter timescale than would have occurred through most of evolutionary time. The study, published on recently  in the journal Trends in Ecology and Evolution, reviewed previous research "where climatic warming is a potential hidden explanatory variable for the occurrence of shape-shifting" and found trends particularly noticeable in birds.

The Australian parrot, for example, had shown an average 4-10 percent increase in the size of its bill since 1871 and the authors said this positively correlated with the summer temperature each year.

Other birds, like North American dark-eyed juncos, thrushes and Galapagos finches also saw bill size increases.

Meanwhile, the wings of the great roundleaf bat grew, the European rabbit developed bigger ears, while the tails and legs of masked shrews were found to be larger.

Shape-shifting does not mean that animals are coping with climate change and that all is 'fine'. It just means they are evolving to survive it -- but we're not sure what the other ecological consequences of these changes are, or indeed that all species are capable of changing and surviving.

It's well known that animals use their appendages to regulate their internal temperature. African elephants, for example, pump warm blood to their large ears, which they then flap to disperse heat.

The beaks of birds perform a similar function – blood flow can be diverted to the bill when the bird is hot. This heat-dispersing function shows the beak is warmer than the rest of the body. All this means there are advantages to bigger appendages in warmer environments.

warm-blooded animals – also known as endotherms – tended to have smaller appendages while those in warmer climates tend to have larger ones.

This pattern became known as Allen's rule, which has since been supported by studies of birds  and mammals.

Biological patterns such as Allen's rule can also help make predictions about how animals will evolve as the climate warms.

https://www.cell.com/trends/ecology-evolution/fulltext/S0169-5347(21)00197-X?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS016953472100197X%3Fshowall%3Dtrue

https://researchnews.cc/news/8818/Animals--shape-shifting--as-clima...

Comment by Dr. Krishna Kumari Challa on September 11, 2021 at 11:25am

What happens when two very different respiratory viruses infect the same cell

We know that several viruses infect us. A recent study from the University of Glasgow has discovered what happens when you get infected with some of these viruses at the same time, and it has implications for how they make us sick and how we protect ourselves from them.

For many reasons, respiratory viruses are often found during winter in the temperate regions of the world, or the rainy season of equatorial regions. During these periods, you'll probably be infected with more than one virus at any one time in a situation called a "co-infection."

Research shows that up to 30% of infections may harbor more than one virus. What this means is that, at some point two different viruses are infecting the cells that line your nose or lungs.

We know that co-infection can be important if we look at a process called "antigenic shift" in influenza viruses, which is basically caused by virus "sex." This sometimes occurs when two different influenza strains meet up inside the same cell and exchange genes, allowing a new variant to emerge.

Co-infection can create a predicament for viruses when you consider that they need to compete for the same resource: you. Some viruses appear to block other viruses, while some viruses seem to like each other. What is driving these positive and negative interactions during co-infections is unknown, but animal studies suggest that it could be critical in determining how sick you get.

The University of Glasgow study investigated what happens when you infect cells in a dish with two human respiratory viruses. For their experiments, they chose IAV and RSV, which are both common and cause lots of disease and death each year. The researchers looked at what happens to each virus using high-resolution imaging techniques, such as cryo-electron microscopy, that their labs have perfected over the years.

They found that some of the human lung cells in the dish contained both viruses. And, by looking closely at those co-infected cells, they found that the viruses that were emerging from the cell had structural characteristics of both IAV and RSV. The new "chimeric" virus particles had proteins of both viruses on their surface and some even contained genes from the other. This is the first evidence of this occurring from co-infection of distinct respiratory viruses.

Follow-up experiments in the same paper showed that these new chimeric viruses were fully functional and could even infect cells that were rendered resistant to influenza, presumably gaining access using the RSV proteins could even get into a broader range of human cells than either virus alone could. Potentially, this could be happening during natural co-infections during the winter.

https://www.biorxiv.org/content/10.1101/2021.08.16.456460v2

https://theconversation.com/heres-what-happens-when-two-very-differ...

Comment by Dr. Krishna Kumari Challa on September 11, 2021 at 11:09am

Heliotropism evolves in response to highly specific environmental conditions, and factors affecting flowers can be different from those impacting leaves.

For example, flowers are all about pollination and seed production. For leaves, it's for maximizing photosynthesis, avoiding over-heating on a hot day or even reducing water loss in harsh and arid conditions.

Some species, such as the Queensland box, arrange their leaves so they're somewhat horizontal in the morning, capturing the full value of the available sunlight. But there are also instances where leaves align vertically to the sun in the middle of the day to minimize the risks of heat damage.

It's easy to think of plants as static organisms. But of course, they are forever changing, responding to their environments and growing. They are dynamic in their own way, and we tend to assume that when they do change, it will be at a very slow and steady pace.

Heliotropism shows us this is not necessarily the case. Plants changing daily can be a little unsettling in that we sense a change but may not be aware of what is causing our unease.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

https://phys.org/news/2021-09-daily-tracking-sun-fascinating.html?u...

Part2

Comment by Dr. Krishna Kumari Challa on September 11, 2021 at 11:08am

Why do some plants track the sun?

Heliotropism,  literally means moving in relation to the sun.

Sunflowers track the course of the sun spectacularly on warm and sunny, spring or summer days. Sometimes they move through an arc of almost 180⁰ from morning to evening.

A number flowering species display heliotropism, including alpine buttercups, arctic poppies, alfalfa, soybean and many of the daisy-type species. So why do they do it?

Flowers are really in the advertising game and will do anything they can to attract a suitable pollinator, as effectively and as efficiently as they can. There are several possible reasons why tracking the sun might have evolved to achieve more successful pollination.

By tracking the sun, flowers absorb more solar radiation and so remain warmer. The warmer temperature suits or even rewards insect pollinators that are more active when they have a higher body temperature.

Optimum flower warmth may also boost pollen development and germination, leading to a higher fertilization rate and more seeds.

So, the flowers are clearly moving. But how?

For many heliotropic flowering species, there's a special layer of cells called the pulvinus just under the flower heads. These cells pump water across their cell membranes in a controlled way, so that cells can be fully pumped up like a balloon or become empty and flaccid. Changes in these cells allow the flower head to move.

When potassium from neighboring plant cells is moved into the cells of the pulvinus, water follows and the cells inflate. When they move potassium out of the cells, they become flaccid.

These potassium pumps are involved in many other aspects of plant movement, too. This includes the opening and closing of stomata (tiny regulated leaf apertures), the rapid movement of mimosa leaves, or the closing of a fly trap.

In 2016, scientists discovered that the pin-up example of heliotropism—the sunflower—had a different way of moving.

They found sunflower movement is due to significantly different growth rates on opposite sides of the flowering stem.

On the east-facing side, the cells grow and elongate quickly during the day, which slowly pushes the flower to face west as the daylight hours go by—following the sun. At night the west-side cells grow and elongate more rapidly, which pushes the flower back toward the east over night.

Everything is then set for the whole process to begin again at dawn next day, which is repeated daily until the flower stops growing and movement ceases.

While many people are aware of heliotropism in flowers, heliotropic movement of leaves is less commonly noticed or known. Plants with heliotropic flowers don't necessarily have heliotropic leaves, and vice versa.

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