Comment

Comment by Dr. Krishna Kumari Challa on November 20, 2021 at 10:54am

While different materials have different densities, liquids, solids and gases of a single material can have different densities as well. You observe this every time you place an ice cube in a glass of water: The ice floats to the top because it is less dense than water.

When water absorbs heat, it changes to its gas phase, steam. Steam occupies 1,700 times the volume as the same number of liquid water molecules. You observe this effect when you boil water in a tea kettle. The force of expanding gas pushes steam out of the kettle through the whistle, causing the squealing noise.

Part 2

Comment by Dr. Krishna Kumari Challa on November 20, 2021 at 10:53am

Why do frozen turkeys explode when deep-fried?

Deep-frying a turkey is a great way to get a delicious, moist meal for Thanksgiving. But this method of cooking can be a very dangerous undertaking.

Every fall, millions of dollars of damage, trips to the ER and even deaths result from attempts to deep-fry turkeys. The vast majority of these accidents happen because people put frozen turkeys into boiling oil. If you are considering deep-frying this year, do not forget to thaw and dry your turkey before placing it in the pot. Failure to do so may lead to an explosive disaster.

What is so dangerous about putting even a partially frozen turkey in a deep-fryer?

The reason frozen turkeys explode, at its core, has to do with differences in density. Density is how much an object weighs given a specific volume. There is a difference in density between oil and water and differences in the density of water between its solid, liquid and gas states. When these density differences interact in just the right way, you get an explosion.

The first important density difference when it comes to frying is that water is more dense than oil. This has to do with how tightly the molecules of each substance pack together and how heavy the atoms are that make up each liquid.

Water molecules are small and pack tightly together. Oil molecules are much larger and don't pack together as well by comparison. Additionally, water is composed of oxygen and hydrogen atoms, while oils are predominantly carbon and hydrogen. Oxygen is heavier than carbon. This means that, for example, one cup of water has more atoms than one cup of oil, and those individuals atoms are heavier. This is why oil floats on top of water. It is less dense.

Part 1

Comment by Dr. Krishna Kumari Challa on November 20, 2021 at 10:28am

This study on UTI was a proof of concept that whole-cell vaccines are more effective in this extreme, lethal-sepsis model. Showing that this works against recurrent UTI would be a significant breakthrough.

Beyond recurrent UTI or urosepsis, researchers think the antigen depot method could be applied broadly to bacterial infections, including endocarditis and tuberculosis.

Michael A. Luzuriaga et al, Metal–Organic Framework Encapsulated Whole-Cell Vaccines Enhance Humoral Immunity against Bacterial Infection, ACS Nano (2021). DOI: 10.1021/acsnano.1c03092

https://phys.org/news/2021-11-scientists-vaccine-method-recurrent-u...

Part 3

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Comment by Dr. Krishna Kumari Challa on November 20, 2021 at 10:27am

Vaccines using whole-cell dead bacteria haven't succeeded because the cells typically don't last long enough in the body to produce long-term, durable immune responses.

That's the reason for  this new MOF antigen depot: It allows an intact, dead pathogen to exist in tissue longer, as if it were an infection, in order to trigger a full-scale immune system response.

The metal-organic framework Gassensmith's team developed encapsulates and immobilizes an individual bacterium cell in a crystalline polymeric matrix that not only kills the bacterium but also preserves and stabilizes the dead cell against high temperature, moisture and organic solvents.

In their experiments, the researchers used a strain of Escherichia coli. There are no vaccines against any pathogenic strain of this bacterium. Uropathogenic E. coli causes about 80% of all community-acquired UTIs.

"When we challenged these mice with a lethal injection of bacteria, after they were vaccinated, almost all of our animals survived, which is a much better performance than with traditional vaccine approaches," Gassensmith said. "This result was repeated multiple times, and we're quite impressed with how reliable it is."

Although the method has not yet been tested in humans, De Nisco said it has the potential to help millions of patients.

part 2

Comment by Dr. Krishna Kumari Challa on November 20, 2021 at 10:08am

Scientists develop promising vaccine method against recurrent UTI

Researchers are investigating the use of whole-cell vaccines to fight urinary tract infection (UTI), part of an effort to tackle the increasingly serious issue of antibiotic-resistant bacteria. They  recently demonstrated the use of metal-organic frameworks (MOFs) to encapsulate and inactivate whole bacterial cells to create a "depot" that allows the vaccines to last longer in the body.

The resulting study, published online Sept. 21 in the American Chemical Society's journal ACS Nano, showed that in mice this method produced substantially enhanced antibody production and significantly higher survival rates compared to standard whole-cell vaccine preparation methods.

Vaccination as a therapeutic route for recurrent UTIs is being explored because antibiotics aren't working anymore. Patients are losing their bladders to save their lives because the bacteria cannot be killed by antibiotics or because of an extreme allergy to antibiotics, which is more common in the older population than people may realize. If not successfully treated, a UTI can lead to sepsis, which can be fatal. Even if you clear the bacteria from the bladder, populations persist elsewhere and usually become resistant to the antibiotic used. When patients accumulate antibiotic resistances, they're eventually going to run out of options.

Vaccines work by introducing a small amount of killed or weakened disease-causing germs, or some of their components, to the body. These antigens prompt the immune system to produce antibodies against a particular disease. Building vaccines against pathogenic bacteria is inherently difficult because bacteria are significantly larger and more complex than viruses. Selecting which biological components to use to create antigens has been a major challenge.

Consequently, using the entire cell is preferable to choosing just a piece of a bacterium

part 1

Comment by Dr. Krishna Kumari Challa on November 20, 2021 at 9:32am

Dengue antibodies can knock out Zika—and vice versa

Cross-protective antibodies from dengue and Zika last far longer than previously thought, scientists have found in a massive study involving more than 4,000 children in Nicaragua.

The 11-year longitudinal analysis unexpectedly revealed that antibodies from either dengue or Zika—which naturally protect against infections caused by either virus—remain stable for years and do not precipitously wane.

Solving scientific mysteries about old foes such as dengue, and an emerging infection like Zika, helps lay the scientific groundwork for better responding to future outbreaks.

It has been previously thought that initial infection with dengue or Zika [viruses] leads to antibodies that are initially protective but wane over time to a point where they become enhancing and drive severe disease.

Cross-reactive antibody protection became abundantly clear during the Zika epidemic of 2015, which swept through multiple Caribbean, Central and South American countries. Stunningly, the incidence of dengue disease dropped dramatically in the midst of the surging Zika outbreak. Dengue and Zika are members of the same family of flaviviruses, so patients who had recovered from dengue infections had cross-protective antibodies capable of neutralizing dengue and Zika. Both viruses are carried by Aedes aegypti mosquitoes.

Yet, previous studies had suggested that the cross-reactive antibodies lasted only two years before dropping to levels that actually made future dengue infections more likely. Scientists in 2015 also had recognized—at least anecdotally—that some people surprisingly had immune protection against the newly emerged Zika virus.

So scientists designed a new study to understand this that allowed them to track antibody responses to initial and secondary dengue as well as to Zika infections. The team focused on community-based and hospital cohorts of children in Nicaragua. To their surprise, instead of diminishing, the antibody kenetics research allowed the scientists to conclude that cross-protective antibodies remained stable for as long as 11 years.

They found that t overall dengue virus iELISA titers stabilized by eight months after primary dengue infection to a half-life longer than a human life and [then] waned.

The half-life, which is longer than a human life, was estimated at 130,000 years, according to the team's research.

The team also observed cross-protective antibodies that were similarly stable in children who were infected with Zika virus. However, the amount of cross-protective antibodies differed across children, which suggests that the quantity of antibodies determines the degree of protection.

Leah C. Katzelnick et al, Dengue and Zika virus infections in children elicit cross-reactive protective and enhancing antibodies that persist long term, Science Translational Medicine (2021). DOI: 10.1126/scitranslmed.abg9478

https://medicalxpress.com/news/2021-11-secrets-antibodies-dengue-zi...

Comment by Dr. Krishna Kumari Challa on November 20, 2021 at 9:03am

The Birth of Microbiology

Comment by Dr. Krishna Kumari Challa on November 19, 2021 at 3:51pm

Severe spinal cord injuries repaired with 'dancing molecules'

https://www.youtube.com/watch?v=Q_xvCE904YU&t=184s

Comment by Dr. Krishna Kumari Challa on November 19, 2021 at 3:28pm

Warmer soil stores less carbon: study

Global warming will cause the world's soil to release carbon, new research shows.

Scientists used data on more than 9,000 soil samples from around the world, and found that carbon storage "declines strongly" as average temperatures increase.

This is an example of a "positive feedback", where global warming causes more carbon to be released into the atmosphere, further accelerating climate change.

Importantly, the amount of carbon that could be released depends on the soil type, with coarse-textured (low-clay) soils losing three times as much carbon as fine-textured (clay-rich) soils.

The researchers  say their findings help to identify vulnerable carbon stocks and provide an opportunity to improve Earth System Models (ESMs) that simulate future climate change.

Because there is more carbon stored in soils than there is in the atmosphere and all the trees on the planet combined, releasing even a small percentage could have a significant impact on our climate.

This analysis identified the carbon stores in coarse-textured soils at high-latitudes (far from the Equator) as likely to be the most vulnerable to climate change.

Such stores, therefore, may require particular attention given the high rates of warming taking place in cooler regions.

In contrast, researchers found carbon stores in fine-textured soils in tropical areas to be less vulnerable to climate warming.

By comparing carbon storage in places with different average temperatures, the researchers estimated the likely impact of global warming.

For every 10°C of increase in temperature, average carbon storage (across all soils) fell by more than 25%.

These results make it clear that, as temperatures rise, more and more carbon is release from soil.

The differences in carbon storage based on soil texture occur because finer soils provide more mineral surface area for carbon-based organic material to bond to, reducing the ability of microbes to access and decompose it.

Temperature effects on carbon storage are controlled by soil stabilisation capacities, Nature Communications (2021). DOI: 10.1038/s41467-021-27101-1

https://phys.org/news/2021-11-warmer-soil-carbon.html?utm_source=nw...

Comment by Dr. Krishna Kumari Challa on November 19, 2021 at 11:19am

Cancer cells use 'tiny tentacles' to suppress the immune system

To grow and spread, cancer cells must evade the immune system. Investigators from Brigham and Women's Hospital and MIT used the power of nanotechnology to discover a new way that cancer can disarm its would-be cellular attackers by extending out nanoscale tentacles that can reach into an immune cell and pull out its powerpack. Slurping out the immune cell's mitochondria powers up the cancer cell and depletes the immune cell. The new findings, published in Nature Nanotechnology, could lead to new targets for developing the next generation of immunotherapy against cancer.

Cancer kills when the immune system is suppressed and cancer cells are able to metastasize, and it appears that nanotubes can help them do both. This is a completely new mechanism by which cancer cells evade the immune system and it gives us a new target to go after.

To investigate how cancer cells and immune cells interact at the nanoscale level, researchers set up experiments in which they co-cultured breast cancer cells and immune cells, such as T cells. Using field-emission scanning electron microscopy, they caught a glimpse of something unusual: Cancer cells and immune cells appeared to be physically connected by tiny tendrils, with widths mostly in the 100-1000 nanometer range. (For comparison, a human hair is approximately 80,000 to 100,000 nanometers). In some cases, the nanotubes came together to form thicker tubes. The team then stained mitochondria—which provide energy for cells—from the T cells with a fluorescent dye and watched as bright green mitochondria were pulled out of the immune cells, through the nanotubes, and into the cancer cells.

By carefully preserving the cell culture condition and observing intracellular structures, researchers saw these delicate nanotubes and they were stealing the immune cells' energy source. It was very exciting because this kind of behavior had never been observed before in cancer cells. The researchers then looked to see what would happen if they prevented the cancer cells from hijacking mitochondria. When they injected an inhibitor of nanotube formation into mouse models used for studying lung cancer and breast cancer, they saw a significant reduction in tumor growth.

Hae Jang, Intercellular nanotubes mediate mitochondrial trafficking between cancer and immune cells, Nature Nanotechnology (2021). DOI: 10.1038/s41565-021-01000-4. www.nature.com/articles/s41565-021-01000-4

https://phys.org/news/2021-11-cancer-cells-tiny-tentacles-suppress....

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