Comment

Comment by Dr. Krishna Kumari Challa on November 5, 2015 at 6:15am

Specialized Cells Help Each Other Survive During Times of Stress
A team led by scientists from the Florida campus of The Scripps Research Institute (TSRI) and the University of Pittsburgh has shown for the first time how one set of specialized cells survives under stress by manipulating the behavior of key immune system cells.

The new study, published recently in the journal Nature Communications, involved mesenchymal stem cells—which live in bone marrow and can differentiate into several different cell types used in bone and connective tissue—and macrophages—immune cells that usually respond to infectious agents or damaged cells by engulfing and devouring them.

“This is the first time anyone has shown how mesenchymal stem cells provide for their own survival by recruiting and then suppressing normal macrophage activity,” said TSRI Professor Donald G. Phinney, who led the study with University of Pittsburgh Associate Professor Luis A. Ortiz. “This finally puts the crosstalk between these cells into the context of cell survival.”

The team’s experiments showed that, like all other cells, mesenchymal stem cells experience stress due to tissue injury and inflammation. When this stress results in damage to the mitochondria (the power houses of the cell), the mesenchymal stem cells recruit the immune system’s macrophages—but in an unusual way.

By reengineering macrophage action with secreted microRNA, the stem cells protect themselves from being targeted and instead package their damaged mitochondria into small sacs known as vesicles and send them out to be engulfed by the macrophage.

Once macrophages subsume the damaged mitochondria, the macrophages are able to repurpose the mitochondria for their own use, replenishing their own energy supplies. Blocking the exchange of damaged mitochondrial to macrophages causes death of the stem cells. Therefore, the process is mutually beneficial.
http://www.nature.com/ncomms/2015/151007/ncomms9472/full/ncomms9472...

Comment by Dr. Krishna Kumari Challa on November 1, 2015 at 12:08pm

Comment by Dr. Krishna Kumari Challa on November 1, 2015 at 11:49am

Comment by Dr. Krishna Kumari Challa on October 31, 2015 at 8:53am

A new study from scientists at The Scripps Research Institute (TSRI) helps explain why cancer metastasis is so hard to stop. The researchers found an additional mechanism explaining how a molecule long linked to cancer progression appears to “seed” the body with metastatic cells long before doctors would typically detect a primary tumor. The molecule, known as epidermal growth factor receptor (EGFR), encourages blood vessel growth early in tumor development—not only feeding the primary tumor, but also providing vehicles for cancer to escape the primary tumor site and travel throughout the body.

“When cancer cells have high levels of EGFR, the tumor has a lot of new, angiogenic blood vessels,” said TSRI Assistant Professor Elena Deryugina, senior author of the new study. “And these vessels are very welcoming for tumor cells and facilitate their dissemination from the very early stages of tumor development.”

The study was published recently in the journal Neoplasia.
When we downregulated EGFR so it wasn’t expressed anymore, the tumor cells were not able to disseminate efficiently,” said TSRI Research Associate Petra Minder, who was first author of the new study. “This gave us a hint that EGFR plays a role in intravasation [an early step of metastatic dissemination during which tumor cells enter angiogenic blood vessels]—we were just not sure how.

The new study shows how EGFR levels make a difference. In experiments using chick embryos, the researchers found that EGFR signaling starts a chain reaction inside tumor cells, ultimately resulting in the release of a molecule called vascular endothelial growth factor (VEGF), known to be active in almost all forms of solid tumors. Released VEGF then binds to endothelial cells, inducing the growth of new blood capillaries and vessels within a developing tumor.

For many years, scientists had seen small blood vessels growing in early-stage tumors, but it was thought these vessels were mostly for supplying tumors with oxygen and nutrients.

“Now we have learned that these newly formed vessels are used by tumor cells for dissemination because of their certain structural properties,” added Deryugina.

The new study shows that these vessels are actually useful for tumors because they are dilated and unusually permeable. Tumor cells can slip into the vessels, escape the primary tumor site and lodge throughout the body. Escaped cells often lie dormant or grow very slowly, not appearing as metastases until after the primary tumor is detected.

The results could also explain why EGFR-inhibiting drugs have had limited success in human patients. While these drugs target EGFR’s effects in primary tumor growth, they don’t address EGFR’s role in blood vessel growth and early metastatic seeding.
The researchers said the findings highlight the urgent need for new methods to diagnose cancers early and new treatments to fight growing metastases.
- http://www.neoplasia.com/article/S1476-5586%2815%2900098-6/abstract

Comment by Dr. Krishna Kumari Challa on October 30, 2015 at 9:19am

All our fears are coming true! Yes, now we hear about Plastic Contamination of Table Salt in China. Supermarket products have tiny plastic particles, probably from ocean pollution attached to sea salt.

People in China who season their meals with sea salt may be unwittingly consuming microscopic pieces of plastic pollution.

When researchers analyzed fifteen brands of common table salt bought at supermarkets across China, they found among the grains of seasoning micro-sized particles of the common water bottle plastic polyethylene terephthalate, as well as polyethylene, cellophane, and a wide variety of other plastics (Env. Sci.& Tech. 2015, DOI: 10.1021/acs.est.5b03163).

The highest level of plastic contamination was found in salt sourced from the ocean: The researchers measured more than 1,200 particles of plastic per lb of sea salt. The team, led by Huahong Shi of East China Normal University also found tiny particles of plastic in salt sourced from briny lakes, briny wells, and salt mines, although at lower levels—between 15 and 800 particles/ lb.

Shi and colleagues argue that plastic contamination originates from the vast amount of plastic pollution floating around marine environments where sea salt is sourced. For instance, bits of plastics might abrade from larger objects, such as water bottles, dumped in the water or they might come from cosmetic products, such as face washes, that use plastic microbeads as exfoliants. The researchers add that other points of entry for plastic contamination are also possible, including during salt processing, drying, and packaging.

Given that manufacturers typically extract sea salt from ocean water by evaporation—a process that leaves everything behind but water—microplastic contamination of sea salt is likely prevalent outside China as well.

Feeling Scary? Then stop using plastic and products made from it as much as possible.

Comment by Dr. Krishna Kumari Challa on October 29, 2015 at 8:42am

Centre for Cellular and Molecular Biology (CCMB) founder-director P M Bhargava on Wednesday became the first Indian scientist to join the bandwagon of writers and filmmakers returning their awards when he told TOI that he will return his Padma Bhushan to protest against "the government's attack on rationalism, reasoning and science".

Bhargava's decision came hours after 107 senior scientists signed an online statement on Wednesday to join the chorus of protests by other scientists, artists and writers.

"The Padma Bhushan had a special place in my collection of more than 100 awards for science. Now I feel no sentimental attachment to it when the government tries to institutionalise religion and curtail freedom and scientific spirit," said Bhargava, who received the Padma award in 1986. He said it was a personal decision and that he had no idea if other scientists would return their awards.

The Indian Constitution in Article 51 A (h) demands ... that we develop scientific temper, humanism and the spirit of inquiry and reform. Unfortunately, what we are witnessing instead is the active promotion of irrational and sectarian thought.

Declaring solidarity with writers who returned their Sahitya Akademi awards, the statement said, "We scientists now join our voices to theirs, to assert that the Indian people will not accept such attacks on reason, science and our plural culture."We appeal to all other sections of society to raise their voice against the assault on reason and scientific temper we are witnessing in India today. The scientists have not sent their statement to any government agency or minister. Rather, they want the government to take note of their protest after reading what the scientist community feels about the state of affairs. Many of the scientists, who are working in the government institutions, including the Delhi-based Indian National Science Academy (INSA), have similar views.

"We are very much with the fellow scientists who have raised the issue of growing intolerance," said a senior scientist of the INSA .

-Times of India

Comment by Dr. Krishna Kumari Challa on October 29, 2015 at 7:43am

Comment by Dr. Krishna Kumari Challa on October 26, 2015 at 8:34am

--
Is it possible for an element 0 to exist? A stable atom with only neutrons and no protons / electrons?
Congratulations! Element zero exists and is a well studied astronomical object. You have just speculated/discovered the existence of the Neutron star. These stars are the densest of stars and exist as a result of Gravitational collapse of a large star after a supernova. The neutron star is about 100,000 times denser than the sun! (The radius of a neutron is about 30,000 times less than that of an atom.) The intense gravitational field is required for neutrons to "clump" together, and the supernova is needed to burn off the protons and electrons.

Specifically, in a supernova the energy is so huge that the atoms are ripped apart, whereupon protons and electrons repel separately and across species move at such different speeds, at a given thermal level, that they dissipate. This leaves neutrons that are pressed closer and closer as they have no electron clouds (which are comprised of mostly vaccum) to keep them apart. Gravity pulls them in tighter and tighter until they are forced to no longer collapse. The prohibition to further collapse is that neutrons are, like electrons, fermions, and thus cannot collapse further than the wavefunction of each particle. Note that atoms are Bosons, so they can collapse further. Stars that are not made only of neutrons can collapse into black holes. Remarkable is it not that quantum theory is needed to explain these very very hot dense mysterious astronomical objects!
**
A single, free neutron cannot form a chemical bond with any element, so I don't know if you could consider it an element, then.

A single, free neutron has a half-life of about 10 minutes. It decays into a proton, electron, and an anti-neutrino. So I don't know if you could consider it stable.

Neutrons have no bonding force to bond any of them together. A neutron star is NOT just a big ball of neutrons, it is much more complicated and in fact has quite a lot of protons and electrons inside it.
*the only chance a neutron will be considered as an element is if it comes for the decay of H+Since H+ (a proton) then it should also decay in a particle? Should it? Otherwise, forget it, a neutron is a particle and not an element.

Applying Lavoisier's principle, nothing is gained, nothing is lost in a chemical reaction, if we start with an element (a proton or H+) and it decays in a neutron they should we have still an element?

Comment by Dr. Krishna Kumari Challa on October 26, 2015 at 7:55am

Comment by Dr. Krishna Kumari Challa on October 26, 2015 at 5:40am

Deep-sea bacteria could help neutralize greenhouse gas

• ‹ Previous
• 1
• …
• 846
• 847
• 848
• 849
• 850
• …
• 1029
• Next ›
• Page