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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...

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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...

Comment by Dr. Krishna Kumari Challa on October 17, 2020 at 6:28am

**Groundbreaking discovery finally proves rain really can move mountains

A pioneering technique that captures precisely how mountains bend to the will of raindrops has helped to solve a long-standing scientific enigma.

The dramatic effect rainfall has on the evolution of mountainous landscapes is widely debated among geologists, but new research led by the University of Bristol and published today in Science Advances, clearly calculates its impact, furthering our understanding of how peaks and valleys have developed over millions of years. Its findings, which focused on the mightiest of mountain ranges—the Himalaya—also pave the way for forecasting the possible impact of climate change on landscapes and, in turn, human life.

It may seem intuitive that more rain can shape mountains by making rivers cut down into rocks faster. But scientists have also thought rain can erode a landscape quickly enough to essentially 'suck' the rocks out of the Earth, effectively pulling mountains up very quickly. Both these theories have been debated for decades because the measurements required to prove them are so painstakingly complicated. That's what makes this discovery such an exciting breakthrough, as it strongly supports the notion that atmospheric and solid earth processes are intimately connected.

When a cosmic particle from outer space reaches Earth, it is likely to hit sand grains on hillslopes as they are transported toward rivers. When this happens, some atoms within each grain of sand can transform into a rare element. By counting how many atoms of this element are present in a bag of sand, we can calculate how long the sand has been there, and therefore how quickly the landscape has been eroding. Once we have erosion rates from all over the mountain range, we can compare them with variations in river steepness and rainfall. However, such a comparison is hugely problematic because each data point is very difficult to produce and the statistical interpretation of all the data together is complicated.

The new model  allows us for the first time to quantify how rainfall affects erosion rates in rugged terrain. Their findings  show how critical it is to account for rainfall when assessing patterns of tectonic activity using topography, and also provide an essential step forward in addressing how much the slip rate on tectonic faults may be controlled by climate-driven erosion at the surface. The study findings also carry important implications for land use management, infrastructure maintenance, and hazards in the Himalaya.

Climate controls on erosion in tectonically active landscapes, Science Advances (2020). advances.sciencemag.org/lookup … .1126/sciadv.aaz3166

https://phys.org/news/2020-10-groundbreaking-discovery-mountains.ht...

Comment by Dr. Krishna Kumari Challa on October 16, 2020 at 10:15am

Glowing blue helps shield this tardigrade from harmful ultraviolet light

Fluorescence may allow water bears to survive in especially sunny regions

When blasted with ultraviolet radiation, a newly discovered species of tardigrade protects itself by glowing blue.

Tardigrades, microscopic animals also known as water bears or moss piglets, are nature’s ultimate survivor. They’re game for temperatures below –270° Celsius and up to 150° C and can withstand the vacuum of space, and some are especially resistant to harmful UV radiation .   One tardigrade ( belonging to the genus Paramacrobiotus)shields itself from that UV radiation with glowing pigments, a new study suggests. It’s the first experimental evidence of fluorescent molecules protecting animals from radiation

H.R. Suma, S. Prakash and S.M. Eswarappa. Naturally occurring fluorescence protects the eutardigrade Paramacrobiotus sp. from ultraviolet radiation. Biology Letters. Published online October 14, 2020. doi: 10.1098/rsbl.2020.0391.

https://www.sciencenews.org/article/tardigrade-water-bear-glow-blue...

Comment by Dr. Krishna Kumari Challa on October 16, 2020 at 9:30am

** Need to be in two places at once? It may be possible

https://researchnews.cc/news/3052/Need-to-be-in-two-places-at-once-...

Comment by Dr. Krishna Kumari Challa on October 16, 2020 at 9:23am

How the brain quenches the thirst in different ways ....

After eating a bag of salty potato chips, you probably feel thirsty. And after a long period of exercise, you also probably feel thirsty. However, these two types of thirst are not the same.

In the first example, you would likely reach for water. This is because after eating chips, the concentration of salts and minerals in your blood becomes elevated, which induces a state called osmotic thirst. On the other hand, after exercising, you are likely to reach for Gatorade or some other fluid that can both rehydrate you and replenish electrolytes, minerals that are important for the body functions. This thirst, called hypovolemic thirst, occurs when the volume of your blood is reduced due to fluid loss from sweating.

Now researchers have discovered unique populations of neurons in the mouse brain that separately drive osmotic thirst and hypovolemic thirst. The research exploited a high-throughput and robust technique for mapping neurons that are activated by a specific behaviour or stimulus.

Two brain regions are known to be important in drinking behaviors in mammals, the subfornical organ (SFO) and the organum vasculosum laminae terminalis (OVLT). The Oka laboratory previously demonstrated that each of these regions contains two general categories of neurons: some that induce drinking behavior and others that inhibit it.

The mice were then genetically modified so that the team could activate the osmolality- and hypovolemia-sensitive neurons with pulses of light, through a technique called optogenetics. The researchers showed that the activation of the osmolality-sensitive neurons drove the mice to drink pure water and to avoid salty water. In contrast, when hypovolemia-sensitive neurons were activated, the mice showed an appetite for mineral-rich liquids.
The results show that thirst is a multimodal sensation caused by distinct stimuli. This is an exciting finding because it illustrates how our brain senses internal states using a very similar strategy as peripheral sensory systems such as taste and olfaction

https://www.caltech.edu/about/news/brain-quenches-thirst-different-...

https://researchnews.cc/news/3054/The-brain-quenches-thirst-in-diff...

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