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Comment by Dr. Krishna Kumari Challa on March 11, 2021 at 11:02am

Bacteria know how to exploit quantum mechanics, study finds

Photosynthetic organisms harvest light from the sun to produce the energy they need to survive. A new paper published by University of Chicago researchers reveals their secret: exploiting quantum mechanics.

Before this study, the scientific community saw quantum signatures generated in biological systems and asked the question, were these results just a consequence of biology being built from molecules, or did they have a purpose?" said Greg Engel, Professor of Chemistry and senior author on the study. "This is the first time we are seeing biology actively exploiting quantum effects.

The scientists studied a type of microorganism called green sulfur bacteria. These bacteria need light to survive, but even small amounts of oxygen can damage their delicate photosynthetic equipment. So they must develop ways to minimize the damage when the bacterium does encounter oxygen.

To study this process, researchers tracked the movement of energy through a photosynthetic protein under different conditions—with oxygen around, and without.

They found that the bacterium uses a quantum mechanical effect called vibronic mixing to move energy between two different pathways, depending on whether or not there's oxygen around. Vibronic mixing involves vibrational and electronic characteristics in molecules coupling to one another. In essence, the vibrations mix so completely with the electronic states that their identities become inseparable. This bacterium uses this phenomenon to guide energy where it needs it to go.

If there's no oxygen around and the bacterium is safe, the bacterium uses vibronic mixing by matching the energy difference between two electronic states in an assembly of molecules and proteins called the FMO complex, with the energy of the vibration of a bacteriochlorophyll molecule. This encourages the energy to flow through the 'normal' pathway toward the photosynthetic reaction center, which is packed full of chlorophyll.

But if there is oxygen around, the organism has evolved to steer the energy through a less direct path where it can be quenched. (Quenching energy is similar to putting a palm on a vibrating guitar string to dissipate energy.) This way, the bacterium loses some energy but saves the entire system.

Jacob S. Higgins et al, Photosynthesis tunes quantum-mechanical mixing of electronic and vibrational states to steer exciton energy transfer, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2018240118

https://phys.org/news/2021-03-bacteria-exploit-quantum-mechanics.ht...

Comment by Dr. Krishna Kumari Challa on March 11, 2021 at 10:55am

Scientists develop new magnetic nanomaterial for counterfeit money prevention

An international research team  has developed a new iron-cobalt-nickel nanocomposite with tunable magnetic properties. The nanocomposite could be used to protect money and securities from counterfeiting. 

The new iron-cobalt-nickel nanocomposite was obtained by chemical precipitation, followed by a reduction process.

The new composite was observed to possess high value of coercivity, which makes the technology applicable e.g. to magnetic rubbers and different magnetically coupled devices. Another potential application is protecting money and securities from counterfeiting.

Tien Hiep Nguyen et al, Impact of Iron on the Fe–Co–Ni Ternary Nanocomposites Structural and Magnetic Features Obtained via Chemical Precipitation Followed by Reduction Process for Various Magnetically Coupled Devices Applications, Nanomaterials (2021). DOI: 10.3390/nano11020341

https://phys.org/news/2021-03-scientists-magnetic-nanomaterial-coun...

Comment by Dr. Krishna Kumari Challa on March 11, 2021 at 6:16am

How trees secretly talk to each other

Comment by Dr. Krishna Kumari Challa on March 10, 2021 at 10:16am

Why sea slugs cut off their own heads Autotomy, the voluntary shedding of a body part, is common to distantly-related animals such as arthropods, gastropods, asteroids, amphibians, and lizards. Autotomy is generally followed by regeneration of shed terminal body parts, such as appendages or tails. A a new type of extreme autotomy ‘s reported recently. Two species of sea slug, Elysia marginata and Elysia atroviridis, decapitate themselves — only to regrow a new body from the severed head. Researchers were astonished to observe slugs in captivity cutting off their own heads after their bodies became infected with parasites. Within 3 weeks, the heads regenerate a whole, parasite-free body, though the bodies never grow back new heads. https://www.cell.com/current-biology/fulltext/S0960-9822(21)00047-6?utm_source=Nature+Briefing&utm_campaign=3d9abe9084-briefing-dy-20210309&utm_medium=email&utm_term=0_c9dfd39373-3d9abe9084-44672165

Comment by Dr. Krishna Kumari Challa on March 10, 2021 at 10:12am

Bacterial film separates water from oil

Researchers have demonstrated that a slimy, yet tough, type of biofilm that certain bacteria make for protection and to help them move around can also be used to separate water and oil. The material may be useful for applications such as cleaning contaminated waters.

They reported the findings of an experiment in which they used a material produced by the bacteria Gluconacetobacter hansenii as a filter to separate water from an oil mixture.

The biofilm the bacteria make and release into their environment is made of cellulose, which is the same material that gives plants a sturdy structure in their cell walls. However, when bacteria make cellulose, it has a tightly packed, crystalline structure. It's one of the purest, if not the purest, forms of cellulose out there. The bacteria make the film to protect themselves.

The material was effective at removing water, and it 's sturdy. The oil doesn't want to go through the membrane; it has a repulsive effect to it. It's super fat-hating.

Researchers see a variety of potential applications for the material in situations where you need to recover water from an oily mixture—whether it be to clean water contaminated with a textile dye or for environmental remediation.

Zahra Ashrafi et al. Bacterial Superoleophobic Fibrous Matrices: A Naturally Occurring Liquid-Infused System for Oil–Water Separation, Langmuir (2021). DOI: 10.1021/acs.langmuir.0c02717

https://phys.org/news/2021-03-bacterial-oil.html?utm_source=nwlette...

Comment by Dr. Krishna Kumari Challa on March 10, 2021 at 10:03am

Humidity in breath makes cotton masks more effective at slowing the spread of COVID-19

Researchers have come up with a better way to test which fabrics work best for masks that are meant to slow the spread of COVID-19. By testing those fabrics under conditions that mimic the humidity of a person's breath, the researchers have obtained measurements that more accurately reflect how the fabrics perform when worn by a living, breathing person.

The new measurements show that under humid conditions, the filtration efficiency—a measure of how well a material captures particles—increased by an average of 33% in cotton fabrics. Synthetic fabrics performed poorly relative to cotton, and their performance did not improve with humidity. The material from medical-procedure masks also did not improve with humidity, though it performed in roughly the same range as cottons.

The filtration efficiency of cotton fabrics increases in humid conditions because cotton is hydrophilic, meaning it likes water. By absorbing small amounts of the water in a person's breath, cotton fibers create a moist environment inside the fabric. As microscopic particles pass through, they absorb some of this moisture and grow larger, which makes them more likely to get trapped.

Most synthetic fabrics, on the other hand, are hydrophobic, meaning they dislike water. These fabrics do not absorb moisture, and their filtration efficiency does not change in humid conditions.

Christopher D. Zangmeister et al, Hydration of Hydrophilic Cloth Face Masks Enhances the Filtration of Nanoparticles, ACS Applied Nano Materials (2021). DOI: 10.1021/acsanm.0c03319

https://phys.org/news/2021-03-humidity-cotton-masks-effective-covid...

Comment by Dr. Krishna Kumari Challa on March 10, 2021 at 8:18am

How to cut onions without crying using science

Comment by Dr. Krishna Kumari Challa on March 9, 2021 at 12:31pm

Ways to spot if someone is trying to mislead you  in science 

It’s not a new thing for people to try to mislead you when it comes to science.

The challenge is to be able to identify when this may be happening. Sometimes it’s easy, as often even the most basic fact-checking and logic can be potent weapons against misinformation.

But often, it can be hard. People who are trying either to make you believe something that isn’t true, or to doubt something that is true, use a variety of strategies that can manipulate you very effectively.

These red flags can alert you ....

1.The ‘us versus them’ narrative: This is one of the most common tactics used to mislead. It taps into our intrinsic distrust of authority and paints those with evidence-based views as part of some other group that’s not be trusted.

2.  ‘I’m not a scientist, but…’: People tend to use the phrase “I’m not a scientist, but…” as a sort of universal disclaimer which they feel allows them to say whatever they want, regardless of scientific accuracy.

3. Reference to ‘the science not being settled’

This is perhaps one of the most powerful strategies used to mislead.

There are of course times when the science is not settled, and when this is the case, scientists openly argue different points of view based on the evidence available.

4. Overly simplistic explanations

Oversimplifications and generalisations are where many conspiracy theories are born.

Science is often messy, complex and full of nuance. The truth can be much harder to explain, and can sometimes sound less plausible, than a simple but incorrect explanation.

We’re naturally drawn to simple explanations. And if they tap into our fears and exploit our cognitive biases — systematic errors we make when we interpret information — they can be extremely seductive.

5. Cherry-picking

People who use this approach treat scientific studies like individual chocolates in a gift box, where you can choose the ones you like and disregard the ones you don’t. Of course, this isn’t how science works.

It’s important to understand not all studies are equal; some provide much stronger evidence than others. You can’t just conveniently put all your faith in the studies that align with your views, and ignore those that don’t.

When scientists evaluate evidence, they go through a systematic process to assess the whole body of evidence. This is a crucial task that requires expertise.

The cherry-picking tactic can be hard to counter because unless you’re across all the evidence, you’re not likely to know whether the studies being presented have been deliberately curated to mislead you.

This is yet another reason to rely on the experts who understand the full breadth of the evidence and can interpret it sensibly.

https://theconversation.com/5-ways-to-spot-if-someone-is-trying-to-...

Comment by Dr. Krishna Kumari Challa on March 9, 2021 at 9:50am

At Dubai airport, travelers' eyes become their passports

Dubai's airport, the world's busiest for international travel, can already feel surreal, with its cavernous duty-free stores, artificial palm trees, gleaming terminals, water cascades and near-Arctic levels of air conditioning.

Now, the key east-west transit hub is rolling out another addition from the realm of science fiction—an iris-scanner that verifies one's identity and eliminates the need for any human interaction when entering or leaving the country.

That's because the airport debuted a new "smart tunnel" that uses biometric technology, instead of human checks, to allow some air travelers to complete passport control in just 15 seconds.

It's the latest artificial intelligence program the United Arab Emirates has launched amid the surging coronavirus pandemic, contact-less technology the government promotes as helping to stem the spread of the virus. But the efforts also have renewed questions about mass surveillance in the federation of seven sheikhdoms, which experts believe has among the highest per capita concentrations of surveillance cameras in the world.

Dubai's airport started offering the program to all passengers last month. On Sunday, travelers stepped up to an iris scanner after checking in, gave it a good look and breezed through passport control within seconds. Gone were the days of paper tickets or unwieldy phone apps.

In recent years, airports across the world have accelerated their use of timesaving facial recognition technology to move passengers to their flights. But Dubai's iris scan improves on the more commonplace automated gates seen elsewhere, authorities said, connecting the iris data to the country's facial recognition databases so the passenger needs no identifying documents or boarding pass.

Now, all the procedures have become 'smart,' around five to six seconds

 Iris biometrics are considered more reliable than surveillance cameras that scan people's faces from a distance without their knowledge or consent.

https://techxplore.com/news/2021-03-dubai-airport-eyes-passports.ht...

https://phys.org/news/2018-10-dubai-airport-biometric-tech.html

Comment by Dr. Krishna Kumari Challa on March 9, 2021 at 9:31am

Do photosynthetic complexes use quantum coherence to increase their...

In a new report now published on Science Advances, Elinor Zerah Harush and Yonatan Dubi in the departments of chemistry and nanoscale science and technology, at the Ben-Gurion University of the Negev, Israel, discussed a direct evaluation of the effects of quantum coherence on the efficiency of three natural photosynthetic complexes. The open quantum systems approach allowed the researchers to simultaneously identify the quantum-nature and efficiency under natural physiological conditions. These systems resided in a mixed quantum-classical regime, which they characterized using dephasing-assisted transport. The efficiency was minimal at best therefore the presence of quantum coherence did not play a substantial role in the process. The efficiency was also independent of any structural parameters, suggesting the role of evolution during structural design for other uses.

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How the growth of ice depends on the fluid dynamics underneath

Researchers of the Toschi group of Eindhoven University of Technology think the water phase change problem with considering the water density anomaly is of great importance relating to common natural phenomena. Their research plan is firstly to understand the physics fundamentals, that is, the coupled problem of the stably and unstably stratified layers with considering the density anomaly.

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