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Comment by Dr. Krishna Kumari Challa on October 18, 2020 at 8:53am

What fuels the beating heart? Study reveals nutrients used by normal and failing hearts

 A team led by scientists in the Perelman School of Medicine at the University of Pennsylvania has produced a detailed picture of fuel and nutrient use by the human heart. The study, published this week in Science, was the first of its kind, involving the simultaneous sampling of blood from different parts of the circulatory system in dozens of human participants, in order to record the levels of related molecules going into and coming out of the beating heart.

The resulting data have revealed key features of fuel use in the normal heart as well as the failing heart, establishing a new framework for studying the heart in health and disease.

Understanding, at this level of detail, how the heart handles fuel and nutrients should inform the development of future treatments for heart failure and related conditions. Now that we have a clear picture of how the heart fuels itself, we can set our sights on devising ways to improve heart metabolism in heart failure.

For the study, Arany and his team simultaneously sampled blood going into the heart and coming out of the heart in 87 subjects—men and women who were already undergoing a procedure to treat a common condition called atrial fibrillation, but who did not have heart failure. The researchers performed a similar sampling in 23 atrial fibrillation patients who did have heart failure. In all patients, the researchers also sampled blood going into and out of the leg, for comparison.

The team then used state-of-the-art tools to quantify the levels of hundreds of different “metabolites”—molecules involved in fuel use and cell growth—in the blood samples. The main aim was to reveal in detail which metabolites the working heart consumes on balance, and which ones it yields as byproducts.

In all, the researchers detected 277 metabolites reliably in the blood of human participants, and found that for 65 of these, levels going out from the heart were significantly different from levels going in.

The team also made some initial comparisons to highlight what may be unique features of normal heart metabolism. For example, the data indicated that the heart, compared to the legs, relies much more heavily on the uptake, apparently as energy sources, of small organic molecules called fatty acids. At the same time, according to the analysis, the heart releases relatively large amounts of a different class of molecules called amino acids—the building blocks and breakdown products of proteins—hinting that a relatively intense breakdown of protein within the heart is one way the working heart muscle fuels its activity.

A big difference between healthy hearts and failing hearts in the study was that the latter consumed more ketones—molecules the body uses as intermediates in its conversion of stored fats to energy—although the researchers suspect that this disparity may have been due merely to the slower passage of blood through the heart, allowing a greater time for ketone uptake. Compared to normal hearts, the failing hearts also released more amino-acids, suggesting more protein breakdown and turnover.

“Whether this increased protein breakdown in heart failure is adaptive or maladaptive will require further studies

https://penntoday.upenn.edu/news/what-fuels-beating-heart-zoltan-arany

https://researchnews.cc/news/3087/What-fuels-the-beating-heart--Stu...

Comment by Dr. Krishna Kumari Challa on October 17, 2020 at 10:48am

Lipid Droplets Are Intracellular Bacteria-Fighting Machines

The antibacterial function of lipid droplets in cells

Far from being inert fat-storage depots within cells, these lipid-loaded organelles recruit immune proteins and block bacterial growth.

Once thought to be little more than blobs of fat inside eukaryotic cells, lipid droplets may in fact provide a first line of defence against invading pathogens, according to evidence published today . This is the first evidence that there’s a direct [immune] mechanism between lipid droplets and intracellular pathogens

Lipid droplets are a type of organelle that exists in all eukaryotic cells. They are jam-packed full of fats, as the name would suggest, and surrounded by a phospholipid monolayer (as opposed to the classic bilayer membrane surrounding most other organelles). Historically lipid droplets have been thought of as sites for storing excess fats and supplying them when and where needed—for instance, to the mitochondria for energy production. More recently, research has shown that certain cell-invading viruses, bacteria, and parasites exploit these fuel-rich droplets for survival and growth.

But, there’s also evidence that the cell laces lipid droplets with antimicrobial proteins, just as a person might lace cheese with poison to rid their house of invading rodents. Lipid droplets in mouse cells, for example, contain the antiviral compound viperin and a protein involved in activating the immune response against foreign antigens, while those in fruit fly cells contain proteins with antibacterial properties.

The new study, from University of Barcelona cell biologist Albert Pol and colleagues, adds to this evidence, showing definitively that lipid droplets in mammalian cells can contain a wealth of immune proteins and have antibacterial activity against a number of bacterial species.

https://science.sciencemag.org/content/370/6514/eaay8085

https://www.the-scientist.com/news-opinion/lipid-droplets-are-intra...

Comment by Dr. Krishna Kumari Challa on October 17, 2020 at 9:04am

Extracting drinkable water from the air

Researchers have developed a solar-powered device that can extract drinkable water directly from the air even in dry regions.

Comment by Dr. Krishna Kumari Challa on October 17, 2020 at 8:54am

Remdesivir and interferon fall flat in WHO’s megastudy of COVID-19 treatments

One of the world’s biggest trials of COVID-19 therapies released its long-awaited interim results yesterday—and they’re a letdown. None of the four treatments in the Solidarity trial, which enrolled more than 11,000 patients in 400 hospitals around the globe, increased survival—not even the much-touted antiviral drug remdesivir. Scientists at the World Health Organization (WHO) released the data as a preprint on medRxiv last night, ahead of its planned publication in The New England Journal of Medicine.

The prospects of two of the four treatments—the malaria drug hydroxychloroquine and the HIV drug combination ritonavir/lopinavir—had faded after another large study, the United Kingdom’s Recovery trial, showed they did not increase survival in June. After analyzing that study and its own data up until then, WHO decided to drop both from the study.

https://www.sciencemag.org/news/2020/10/remdesivir-and-interferon-f...

Comment by Dr. Krishna Kumari Challa on October 17, 2020 at 8:39am

Research shows Krebs cycle possible without metals or enzyme catalysts, offers new clues to life's origins

This is a new study  that may fundamentally alter humanity's understanding of the origin of life.

The study describes how organic chemical reactions could have started inorganically for the first time billions of years ago, according to a research discovery . One of those elemental metabolic processes is called the Krebs cycle, also known as the citric acid cycle. 

This study represents the first time the Krebs cycle has been replicated synthetically.

They started with some small molecules and figured out how to make the Krebs cycle run, and it runs without enzymes in water at mild pH. These discoveries have potential applications in understanding how life started on Earth, and where else in the universe it may emerge.

What's in living cells?" Stubbs asked. "What are some of those core components that must have existed very early on? The answer is the citric acid cycle. This is one of the processes that turns food into energy. It doesn't matter whether you're human, plant, lizard, whatever … So it's likely this cycle existed near the origins of life, and that's what this paper is all about—how could simpler versions of this cycle, which now requires complex biological machinery to operate, have operated from the beginning without any of that evolved hardware?

This discovery also led to novel ways to chemically synthesize biological diagnostic agents used in an emerging cancer and bacterial infection detection diagnostic method called metabolic flux analysis.

 R. Trent Stubbs et al. A plausible metal-free ancestral analogue of the Krebs cycle composed entirely of α-ketoacids, Nature Chemistry (2020). DOI: 10.1038/s41557-020-00560-7

https://phys.org/news/2020-10-krebs-metals-enzyme-catalysts-clues.h...

Comment by Dr. Krishna Kumari Challa on October 17, 2020 at 8:32am

New feature found in energy spectrum of universe's most powerful particles

Particles smaller than an atom hurtle through the universe nearly at the speed of light, blasted into space from something, somewhere, in the cosmos.

A scientific collaboration of the Pierre Auger Observatory, including researchers from the University of Delaware, has measured the most powerful of these particles—ultra-high-energy cosmic rays—with unprecedented precision. In doing so, they have found a "kink" in the energy spectrum that is shining more light on the possible origins of these subatomic space travelers.

The team's findings are based on the analysis of 215,030 cosmic ray events with energies above 2.5 quintillion electron volts (eV), recorded over the past decade by the Pierre Auger Observatory in Argentina. It is the largest observatory in the world for studying cosmic rays.

The new spectral feature, a kink in the cosmic-ray energy spectrum at about 13 quintillion electron volts, represents more than points plotted on a graph. It brings humanity a step closer to solving the mysteries of the most energetic particles in nature. Through this latest analysis, we can further corroborate our earlier indications that ultra-high-energy cosmic rays are not just protons of hydrogen, but also a mix of nuclei from heavier elements, and this composition changes with energy.

A. Aab et al. Features of the Energy Spectrum of Cosmic Rays above 2.5×1018 eV Using the Pierre Auger Observatory, Physical Review Letters (2020). DOI: 10.1103/PhysRevLett.125.121106

A. Aab et al. Measurement of the cosmic-ray energy spectrum above 2.5×1018 eV using the Pierre Auger Observatory, Physical Review D (2020). DOI: 10.1103/PhysRevD.102.062005

https://phys.org/news/2020-10-feature-energy-spectrum-universe-powe...

Comment by Dr. Krishna Kumari Challa on October 17, 2020 at 8:27am

Slowing light in an optical cavity with mechanical resonators and mirrors

Theoretical physicists  have shown that a position-dependent mass optomechanical system involving a cavity between two mirrors, one attached to a resonator, can enhance induced transparency and reduce the speed of light.

We are all taught at high school that the speed of light through a vacuum is about 300000km/s, which means that a beam from Earth takes about 2.5 seconds to reach the Moon. It naturally moves more slowly through transparent objects, however, and scientists have found ways to slow it dramatically. Optomechanics, or the interaction of electromagnetic radiation with mechanical systems, is a relatively new and effective way of approaching this. Theoretical physicists have now demonstrated how light is slowed in a position-based mass optomechanical system. This work has been published in EPJ D.

They describe cavity optomechanics, which involves optical modes set up in a cavity between mirrors. The cavity mode, which is driven by a strong field and probed by a weak field, provides a 'playground' for investigating phenomena including slow light and optomechanically induced transparency (OMIT). The latter is a quantum effect in which the optical response of atoms and molecules is controlled by an electromagnetic field. In this work, the physicists studied a cavity system comprising a fixed mirror and a movable one. The moving mirror oscillates along the axis of the cavity with a single harmonic frequency. By considering the total mass of the resonator as dependent on its position, and calculating the effective Hamiltonian of the whole system (which describes its total energy), the physicists showed how the system can enhance OMIT and slow light. As the mass is position-dependent, the system is non-linear and the nature and magnitude of the quantum effects observed depend strongly on the value of a non-linear parameter, alpha.

 Kamran Ullah et al. Enhanced optomechanically induced transparency and slow/fast light in a position-dependent mass optomechanics, The European Physical Journal D (2020). DOI: 10.1140/epjd/e2020-10286-1

https://phys.org/news/2020-10-optical-cavity-mechanical-resonators-...

Comment by Dr. Krishna Kumari Challa on October 17, 2020 at 7:40am

Zeptoseconds: New world record in short time measurement

In 1999,  chemist Ahmed Zewail received the Nobel Prize for measuring the speed at which molecules change their shape. He founded femtochemistry using ultrashort laser flashes: the formation and breakup of chemical bonds occurs in the realm of femtoseconds.

Now, atomic physicists have for the first time studied a process that is shorter than femtoseconds by magnitudes. They measured how long it takes for a photon to cross a hydrogen molecule: about 247 zeptoseconds for the average bond length of the molecule. This is the shortest timespan that has been successfully measured to date.

The scientists carried out the time measurement on a hydrogen molecule (H₂) which they irradiated with X-rays from the X-ray laser source PETRA III at the Hamburg accelerator facility DESY. The researchers set the energy of the X-rays so that one photon was sufficient to eject both electrons out of the hydrogen molecule.

Zeptosecond Birth Time Delay in Molecular Photoionization, Science (2020). DOI: 10.1126/science.abb9318

https://phys.org/news/2020-10-zeptoseconds-world-short.html?utm_sou...

--

Electrons behave like particles and waves simultaneously, and therefore the ejection of the first electron resulted in electron waves launched first in the one, and then in the second hydrogen molecule atom in quick succession, with the waves merging.

The photon behaved here much like a flat pebble that is skimmed twice across the water: when a wave trough meets a wave crest, the waves of the first and second water contact cancel each other, resulting in what is called an interference pattern.

The scientists measured the interference pattern of the first ejected electron using the COLTRIMS reaction microscope, an apparatus that Dörner helped develop and which makes ultrafast reaction processes in atoms and molecules visible. Simultaneously with the interference pattern, the COLTRIMS reactions microscope also allowed the determination of the orientation of the hydrogen molecule. The researchers here took advantage of the fact that the second electron also left the hydrogen molecule, so that the remaining hydrogen nuclei flew apart and were detected.

Comment by Dr. Krishna Kumari Challa on October 17, 2020 at 7:27am

Ultrafast camera films 3-D movies at 100 billion frames per second

In his quest to bring ever-faster cameras to the world researchers  have developed technology that can reach blistering speeds of 70 trillion frames per second, fast enough to see light travel. Just like the camera in your cell phone, though, it can only produce flat images.

Now, they have gone a step further to create a camera that not only records video at incredibly fast speeds but does so in three dimensions.

The new camera, which uses the same underlying technology as other compressed ultrafast photography (CUP) cameras, is capable of taking up to 100 billion frames per second. That is fast enough to take 10 billion pictures, more images than the entire human population of the world, in the time it takes you to blink your eye.

Single-shot stereo-polarimetric compressed ultrafast photography for light-speed observation of high-dimensional optical transients with picosecond resolution, Nature Communications (2020).

https://www.nature.com/articles/s41467-020-19065-5

https://phys.org/news/2020-10-ultrafast-camera-d-movies-billion.htm...

Comment by Dr. Krishna Kumari Challa on October 17, 2020 at 6:38am

Calcium bursts kill drug-resistant tumour cells

Multidrug resistance (MDR)—a process in which tumors become resistant to multiple medicines—is the main cause of failure of cancer chemotherapy. Tumor cells often acquire MDR by boosting their production of proteins that pump drugs out of the cell, rendering the chemotherapies ineffective. Now, researchers reporting in ACS' Nano Letters have developed nanoparticles that release bursts of calcium inside tumor cells, inhibiting drug pumps and reversing MDR.

A pump protein called P-glycoprotein (P-gp) often plays a key role in MDR. P-gp is in the cell membrane, where it uses energy in the form of adenosine triphosphate (ATP) to pump drugs out of tumor cells. Scientists have tried to block P-gp in various ways, such as with small-molecule inhibitors or by depleting ATP. However, the strategies used so far can cause side effects, or they are unstable in the body. Some of the treatments can be difficult to prepare. Kaixiang Zhang, Zhenzhong Zhang, Jinjin Shi and colleagues wanted to block P-gp using a different approach. Previous research suggested that overloading tumor cells with calcium ions could both decrease production of P-gp and reduce ATP levels. But the team needed to find a way to deliver bursts of calcium, along with a chemotherapy drug, inside cancer cells.

The researchers made a "calcium ion nanogenerator" (TCaNG) by loading calcium phosphate nanoparticles with the chemotherapy drug doxorubicin and then coating them with molecules that would allow TCaNG to target and enter cancer cells. Once inside cells, TCaNGs entered an acidic compartment, where the TCaNGs disintegrated, releasing both doxorubicin and bursts of calcium ions. When the team tested TCaNG on cancer cells in a petri dish in the lab, both ATP and P-gp production decreased, which allowed doxorubicin to kill the previously resistant tumor cells. When tested in tumor-bearing mice, TCaNG-treated mice showed significantly smaller tumors after 21 days of treatment than control mice, with no apparent side effects.

Junjie Liu et al, Nanoenabled Intracellular Calcium Bursting for Safe and Efficient Reversal of Drug Resistance in Tumor Cells, Nano Letters (2020). DOI: 10.1021/acs.nanolett.0c03042

https://phys.org/news/2020-10-calcium-drug-resistant-tumor-cells.ht...

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