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Comment by Dr. Krishna Kumari Challa on February 3, 2021 at 11:50am

Venus flytraps found to produce magnetic fields

The Venus flytrap (Dionaea muscipula) is a carnivorous plant that encloses its prey using modified leaves as a trap. During this process, electrical signals known as action potentials trigger the closure of the leaf lobes. An interdisciplinary team of scientists has now shown that these electrical signals generate measurable magnetic fields. Using atomic magnetometers, it proved possible to record this biomagnetism.

The problem is that the magnetic signals in plants are very weak, which explains why it was extremely difficult to measure them with the help of older technologies.

We know that in the human brain, voltage changes in certain regions result from concerted electrical activity that travels through nerve cells in the form of action potentials. Techniques such as electroencephalography (EEG), magnetoencephalography (MEG) and magnetic resonance imaging (MRI) can be used to record these activities and noninvasively diagnose disorders. When plants are stimulated, they also generate electrical signals, which can travel through a cellular network analogous to the human and animal nervous system.

Researchers have now demonstrated that electrical activity in the Venus flytrap is also associated with magnetic signals.The action potentials in a multicellular plant system produce measurable magnetic fields, something that had never been confirmed before.

The trap of Dionaea muscipula consists of bilobed trapping leaves with sensitive hairs, which, when touched, trigger an action potential that travels through the whole trap. After two successive stimuli, the trap closes and any potential insect prey is locked inside and subsequently digested. Interestingly, the trap is electrically excitable in a variety of ways: in addition to mechanical influences such as touch or injury, osmotic energy, for example salt-water loads, and thermal energy in the form of heat or cold can also trigger action potentials. For their study, the research team used heat stimulation to induce action potentials, thereby eliminating potentially disturbing factors such as mechanical background noise in their magnetic measurements.

While biomagnetism has been relatively well-researched in humans and animals, so far very little equivalent research has been done in the plant kingdom, using only superconducting-quantum-interference-device (SQUID) magnetometers, bulky instruments which must be cooled to cryogenic temperatures. For the current experiment, the research team used atomic magnetometers to measure the magnetic signals of the Venus flytrap. The sensor is a glass cell filled with a vapor of alkali atoms, which react to small changes in the local magnetic-field environment. These optically pumped magnetometers are more attractive for biological applications because they do not require cryogenic cooling and can also be miniaturized.

The researchers detected magnetic signals with an amplitude of up to 0.5 picotesla from the Venus flytrap, which is millions of times weaker than the Earth's magnetic field. "The signal magnitude recorded is similar to what is observed during surface measurements of nerve impulses in animals.

Anne Fabricant et al. Action potentials induce biomagnetic fields in carnivorous Venus flytrap plants, Scientific Reports (2021). DOI: 10.1038/s41598-021-81114-w

https://phys.org/news/2021-02-venus-flytraps-magnetic-fields.html?u...

Comment by Dr. Krishna Kumari Challa on February 3, 2021 at 11:43am

Temperature, humidity, wind predict second wave of pandemic

The 'second wave' of the coronavirus pandemic has resulted in much blame placed on a lack of appropriate safety measures. However, due to the impacts of weather, research suggests two outbreaks per year during a pandemic are inevitable.

Though face masks, travel restrictions, and social distancing guidelines help slow the number of new infections in the short term, the lack of climate effects incorporated into epidemiological models presents a glaring hole that can cause long-term effects.

Typical models for predicting the behavior of an epidemic contain only two basic parameters, transmission rate and recovery rate. These rates tend to be treated as constants, but  this is not actually the case. Temperature, relative humidity, and wind speed all play a significant role, so the researchers aimed to modify typical models to account for these climate conditions. They call their new weather-dependent variable the Airborne Infection Rate index.

When they applied the AIR index to models of Paris, New York City, and Rio de Janeiro, they found it accurately predicted the timing of the second outbreak in each city, suggesting two outbreaks per year is a natural, weather-dependent phenomenon. Further, the behavior of the virus in Rio de Janeiro was markedly different from the behavior of the virus in Paris and New York, due to seasonal variations in the northern and southern hemispheres, consistent with real data.

The authors emphasize the importance of accounting for these seasonal variations when designing safety measures.

As temperatures rise and humidity falls, scientists expect another improvement in infection numbers, though they note that mask and distancing guidelines should continue to be followed with the appropriate weather-based modifications.

Talib Dbouk and Dimitris Drikakis. Fluid dynamics and epidemiology: Seasonality and transmission dynamics. Physics of Fluids 33, 021901 (2021); doi.org/10.1063/5.0037640

https://phys.org/news/2021-02-temperature-humidity-pandemic.html?ut...

Comment by Dr. Krishna Kumari Challa on February 3, 2021 at 11:37am

How do electrons close to Earth reach almost the speed of light?

A new study found that electrons can reach ultra-relativistic energies for very special conditions in the magnetosphere when space is devoid of plasma.

Recent measurements from NASA's Van Allen Probes spacecraft showed that electrons can reach ultra-relativistic energies flying at almost the speed of light.  Researchers  have revealed under which conditions such strong accelerations occur. They had already demonstrated in 2020 that during solar storm plasma waves play a crucial role for that. However, it was previously unclear why such high electron energies are not achieved in all solar storms. In the journal Science Advances, they now show that extreme depletions of the background plasma density are crucial.

At ultra-relativistic energies, electrons move at almost the speed of light. Then the laws of relativity become most important. The mass of the particles increases by a factor ten, time is slowing down, and distance decreases. With such high energies, charged particles become most dangerous to even the best protected satellites. As almost no shielding can stop them, their charge can destroy sensitive electronics. Predicting their occurrence—for example, as part of the observations of space weather practiced at the GFZ—is therefore very important for modern infrastructure.

This study shows that electrons in the Earth's radiation belt can be promptly accelerated locally to ultra-relativistic energies, if the conditions of the plasma environment—plasma waves and temporarily low plasma density—are right. The particles can be regarded as surfing on plasma waves. In regions of extremely low plasma density they can just take a lot of energy from plasma waves. Similar mechanisms may be at work in the magnetospheres of the outer planets such as Jupiter or Saturn and in other astrophysical objects.

 Hayley J. Allison et al, Gyroresonant wave-particle interactions with chorus waves during extreme depletions of plasma density in the Van Allen radiation belts, Science Advances (2021). DOI: 10.1126/sciadv.abc0380

https://phys.org/news/2021-02-electrons-earth.html?utm_source=nwlet...

Comment by Dr. Krishna Kumari Challa on February 3, 2021 at 11:30am

Why food sticks to nonstick frying pans

Despite the use of nonstick frying pans, foods will sometimes get stuck to a heated surface, even if oil is used. The results can be very messy and unappetizing.

Scientists at the Czech Academy of Sciences began an investigation of the fluid properties of oil on a flat surface, such as a frying pan. Their work, reported in Physics of Fluids, shows convection may be to blame for our stuck-on food.

The experimental investigation used a nonstick pan with a surface comprised of ceramic particles. A video camera was placed above the pan as it was heated and used to measure the speed at which a dry spot formed and grew. Further experiments with a Teflon-coated pan showed the same.

Researchers experimentally explained why food sticks to the center of the frying pan. This is caused by the formation of a dry spot in the thin sunflower oil film as a result of thermocapillary convection.

When the pan is heated from below, a temperature gradient is established in the oil film. For common liquids, such as the sunflower oil used in the experiment, the surface tension decreases when temperature increases. A surface tension gradient is established, directed away from the center where the temperature is higher and toward the pan's periphery.

This gradient sets up a type of convection known as thermocapillary convection, which moves oil outward. When the oil film in the middle becomes thinner than a critical value, the film ruptures.

The researchers determined the conditions that lead to dry spots for both stationary and flowing films. These conditions include a decrease in the local film thickness below a critical size as well as the size of the deformed region falling below a number known as the capillary length.

"To avoid unwanted dry spots, the following set of measures should be applied: increasing the oil film thickness, moderate heating, completely wetting the surface of the pan with oil, using a pan with a thick bottom, or stirring food regularly during cooking.

The phenomenon also occurs in other situations, such as the thin liquid films used in fluid distillation columns or other devices that may have electronic components.

"Dry spot formation or film rupture plays a negative role, resulting in sharp overheating of the electronic components. The results of this study may, therefore, have wider application.

"On formation of dry spots in heated liquid films" Physics of Fluids (2021). DOI: 10.1063/5.0035547

https://phys.org/news/2021-02-food-nonstick-pans.html?utm_source=nw...

Comment by Dr. Krishna Kumari Challa on February 3, 2021 at 11:25am

Researchers map non-visible materials at nanoscale with ultrasound

The increasing miniaturization of electrical components in industry requires a new imaging technique at the nanometre scale. Delft researcher Gerard Verbiest and ASML have developed a first proof-of-concept method that they now plan to further develop. The method uses the same principle as ultrasound scanning in pregnancies, but on a much, much smaller scale.

Existing non-destructive imaging techniques for nanoelectronics, such as optical and electron microscopy, are not accurate enough or applicable to deeper structures. A well-known 3-D technique on a macro-scale is ultrasound. The advantage here is that it works for every sample. That makes ultrasound an excellent way of mapping the 3-D structure of a non-transparent sample in a non-destructive way." And yet, ultrasound technology at the nanoscale didn't exist yet. Indeed, the resolution of ultrasound imaging is strongly determined by the wavelength of the sound used, and that is typically around a millimeter.

o improve this, ultrasound has already been integrated into an Atomic Force Microscope (AFM).

AFM is a technique that allows you to scan and map out surfaces extremely accurately with a tiny needle. The advantage here is that it isn't the wavelength but the size of the tip of the AFM that determines the resolution. Unfortunately, at the frequencies used so far (1-10 MHz), the response of the AFM is small and unclear. We do see something, but it's not clear exactly what we're seeing. So the frequency of the sound used needed to be further increased, to the GHz range, and that's what these researchers have now done.

They have achieved this  through photoacoustics. Using the photoacoustic effect allows you to generate extremely short sound pulses. Researchers have managed to integrate this technique into an AFM. With the tip of the AFM, they c ould focus the signal. 

But there are certainly potential applications outside of electronics as well. You could use it in cell biology to make a detailed 3-D image of a single living cell, for example of the way mitochondria are folded in a cell. And in materials science, you could use it for research into heat transport in an amazing material such as graphene."

https://phys.org/news/2021-02-non-visible-materials-nanoscale-ultra...

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Comment by Dr. Krishna Kumari Challa on February 3, 2021 at 11:19am

Twisted van der Waals materials as a new platform to realize exotic...

Researchers from the MPSD, the RWTH Aachen University and the Flatiron Institute, Columbia University (both in the U.S.) and part of the Max Planck—New York City Center for Non-equilibrium Quantum Phenomena have provided a fresh perspective on the potential of twisted van der Waals materials for realizing novel and elusive states of matter and providing a unique materials-based quantum simulation platform.

Comment by Dr. Krishna Kumari Challa on February 3, 2021 at 8:54am

Say goodbye to the dots and dashes to enhance optical storage media

Innovators have created technology aimed at replacing Morse code with colored "digital characters" to modernize optical storage. They are confident the advancement will help with the explosion of remote data storage during and after the COVID-19 pandemic.

Morse code has been around since the 1830s. The familiar dots and dashes system may seem antiquated given the amount of information needed to be acquired, digitally archived and rapidly accessed every day. But those same basic dots and dashes are still used in many optical media to aid in storage.

A new technology developed at Purdue is aimed at modernizing the optical digital storage technology. Rather than using the traditional dots and dashes as commonly used in these technologies, the  innovators encode information in the angular position of tiny antennas, allowing them to store more data per unit area.

The storage capacity greatly increases because it is only defined by the resolution of the sensor by which you can determine the angular positions of antennas. They mapped the antenna angles into colors, and the colors are decoded.

This advancement allows for more data to be stored and for that data to be read at a quicker rate. The research is published in Laser & Photonics Reviews.

 Maowen Song et al, Enabling Optical Steganography, Data Storage, and Encryption with Plasmonic Colors, Laser & Photonics Reviews (2021). DOI: 10.1002/lpor.202000343

https://phys.org/news/2021-02-goodbye-dots-dashes-optical-storage.h...

Comment by Dr. Krishna Kumari Challa on February 3, 2021 at 8:41am

A new way to make wood transparent, stronger and lighter than glass

A team of researchers at the University of Maryland, has found a new way to make wood transparent. In their paper published in the journal Science Advances, the group describes their process and why they believe it is better than the old process.

Qinqin Xia et al. Solar-assisted fabrication of large-scale, patternable transparent wood, Science Advances (2021). DOI: 10.1126/sciadv.abd7342

https://phys.org/news/2021-02-wood-transparent-stronger-lighter-gla...

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Comment by Dr. Krishna Kumari Challa on February 3, 2021 at 8:38am

An origami-inspired medical patch for sealing internal injuries

Many surgeries today are performed via minimally invasive procedures, in which a small incision is made and miniature cameras and surgical tools are threaded through the body to remove tumors and repair damaged tissues and organs. The process results in less pain and shorter recovery times compared to open surgery.

While many procedures can be performed in this way, surgeons can face challenges at an important step in the process: the sealing of internal wounds and tears.

The bioadhesives currently used in minimally invasive surgeries are available mostly as biodegradable liquids and glues that can be spread over damaged tissues. When these glues solidify, however, they can stiffen over the softer underlying surface, creating an imperfect seal. Blood and other biological fluids can also contaminate glues, preventing successful adhesion to the injured site. Glues can also wash away before an injury has fully healed, and, after application, they can also cause inflammation and scar tissue formation.

Taking inspiration from origami, MIT engineers have now designed a medical patch that can be folded around minimally invasive surgical tools and delivered through airways, intestines, and other narrow spaces, to patch up internal injuries. The patch resembles a foldable, paper-like film when dry. Once it makes contact with wet tissues or organs, it transforms into a stretchy gel, similar to a contact lens, and can stick to an injured site.

Given the limitations of current designs, the team aimed to engineer an alternative that would meet three functional requirements. It should be able to stick to the wet surface of an injured site, avoid binding to anything before reaching its destination, and once applied to an injured site resist bacterial contamination and excessive inflammation.

The team's design meets all three requirements, in the form of a three-layered patch. The middle layer is the main bioadhesive, made from a hydrogel material that is embedded with compounds called NHS esters. When in contact with a wet surface, the adhesive absorbs any surrounding water and becomes pliable and stretchy, molding to a tissue's contours. Simultaneously, the esters in the adhesive form strong covalent bonds with compounds on the tissue surface, creating a tight seal between the two materials. 

This could be used to repair a perforation from a coloscopy, or seal solid organs or blood vessels after a trauma or elective surgical intervention. Instead of having to carry out a full open surgical approach, one could go from the inside to deliver a patch to seal a wound at least temporarily and maybe even long-term.

In contrast to existing surgical adhesives, the team's new tape is designed to resist contamination when exposed to bacteria and bodily fluids. Over time, the patch can safely biodegrade away. The team has published its results in the journal Advanced Materials.

Sarah J. Wu et al. A Multifunctional Origami Patch for Minimally Invasive Tissue Sealing, Advanced Materials (2021). DOI: 10.1002/adma.202007667

https://phys.org/news/2021-02-origami-inspired-medical-patch-intern...

Comment by Dr. Krishna Kumari Challa on February 2, 2021 at 11:59am

A new treatment to help people with a spinal cord injury

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