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Comment by Dr. Krishna Kumari Challa on July 31, 2022 at 9:51am

Scientists engineer DNA 'receipt book' to store cells' history

If you want to track a person's activities for a day, you could call them up every ten minutes and ask what they're doing. Easier, though, would be to provide them with a journal to log their own actions. Scientists often rely on a method akin to the first to track how cells change over time; they pick cells out of a group at set time points and take a snapshot of their genetic activity.

Now, researchers have developed a tool more like a journal or receipt book—it logs a cell's genetic activity for days at a time. The biological device, named a Retro-Cascorder, records data within strands of DNA, which can then be analyzed at any time to get the cell's activity log.

This new way of collecting molecular data gives us an unprecedented window into cells.  In addition to providing a new tool for basic research, it lets us engineer cells to be living biosensors that can record changes to their environment.

While all cells within an organism have identical genomes, they differ in which genes are turned on or off at any given time. Researchers can measure the degree to which a given gene is turned on inside a cell at different timepoints to track how the cell's behavior, function, or identity changes over time.

 wanted to engineer a system that would automatically record every time a particular gene was turned on. This would provide a more detailed look at a gene's activity pattern.

To show the utility of their new Retro-Cascorder, scientists engineered Escherichia coli (E. coli) cells to contain retrons in genes that were known to be activated in the presence of certain chemicals. They showed that, over 48 hours, a CRISPR array could accurately record the order in which these genes were turned on—and therefore the order in which the researchers added these chemicals.

"Researchers could install multiple biosensors in a cell and use them to monitor an environment over time, from a pond or wastewater facility to the inside of the human gut.

So far, researchers have only used the system to track a few genes at a time, rather than the many dozens that researchers might want to simultaneously monitor in the future. But the team is actively working on ways to expand Retro-Cascorders and adapt the system for use in cell types other than bacteria.

The paper, "Recording gene expression order in DNA by CRISPR addition of retron barcodes," was published in the journal Nature on July 27, 2022.

https://www.nature.com/articles/s41586-022-04994-6

Comment by Dr. Krishna Kumari Challa on July 31, 2022 at 9:50am

How soft sounds might dull pain in mice

Comment by Dr. Krishna Kumari Challa on July 29, 2022 at 12:14pm

Fossil-fuel emissions hamper carbon dating

The burning of fossil fuels has officially shifted the composition of carbon isotopes in the air of the Northern Hemisphere enough to cancel out a useful signal from nuclear-weapons testing. This could cause a headache for archaeologists, because modern items now look like objects from the early twentieth century in terms of radiocarbon dating. The development means that forensic scientists will no longer be able to use radiocarbon fingerprints to pinpoint the ages of materials such as ivory, antiques and wine. “If you’re working in forensics or detecting fakes, this is a really sad moment.

Carbon dating hampered by rising fossil-fuel emissions

Archaeologists will increasingly have to rely on other techniques as emissions continue to alter the composition of carbon isotopes in air.

https://www.nature.com/articles/d41586-022-02057-4?utm_source=Natur...

Comment by Dr. Krishna Kumari Challa on July 29, 2022 at 11:58am

“This supports a scenario in which the market was the epicenter of the epidemic,” Worobey, a viral evolution expert, said. “With vendors getting infected first and setting off a chain of infections among community members surrounding the area.” The second study analyses SARS-CoV-2 genomic data from early cases. The researchers combined epidemic modeling with analyses of the virus's early evolution based on the earliest sampled genomes. They determined that the pandemic, which initially involved two subtly distinct lineages of SARS-CoV-2, likely arose from at least two separate infections of humans from animals at the Huanan market in November 2019 and perhaps in December 2019. The analyses also suggested that, in this period, there were many other animal-to-human transmissions of the virus at the market that failed to manifest in recorded COVID-19 cases. The authors used a technique known as molecular clock analysis, which relies on the natural pace with which genetic mutations occur over time, to establish a framework for the evolution of the SARS-CoV-2 virus lineages. They found that a scenario of a singular introduction of the virus into humans rather than multiple introductions would be inconsistent with molecular clock data. The two studies provide evidence that COVID-19 originated via jumps from animals to humans at the Huanan market, likely following transmission to those animals from coronavirus-carrying bats in the wild or on farms in China. The researchers say scientists and public officials should seek better understanding of the wildlife trade in China and elsewhere and promote more comprehensive testing of live animals sold in markets to lower the risk of future pandemics. The teams include more than 30 scholars from 20 different universities and research centers, including UCLA, the University of California San Diego, the Scripps Research Institute, the University of Arizona, and Johns Hopkins University in the U.S., among others. Part 2 ** https://researchnews.cc/news/14459/Scientists-confirm-COVID-tied-to...

Comment by Dr. Krishna Kumari Challa on July 29, 2022 at 11:57am

Scientists confirm COVID tied to wildlife sales at Chinese market

An international team of researchers has confirmed that live animals sold at the Huanan Seafood Wholesale Market were the likely source of the COVID-19 pandemic that has claimed 6.4 million lives since it began nearly three years ago.

“Rigorously combining all available evidence surrounding the emergence of SARS-CoV-2 clearly demonstrates that the virus jumped at least twice from animals to humans at the Huanan market,” said Dr. Marc Suchard, UCLA Fielding School of Public Health professor of biostatistics. “Identifying multiple transmission events finally puts to rest a single origin from elsewhere.”

Co-led by Suchard and Dr. Michael Worobey (University of Arizona), Dr. Joel Wertheim (UCSD) and Dr. Kristian Andersen (Scripps Research Institute), international teams of researchers have traced the start of the pandemic to the market in Wuhan, China, where foxes, raccoon dogs, and other live mammals susceptible to the virus were sold immediately before the pandemic began. Their findings were published Tuesday in two peer-reviewed papers in the journal Science, after being previously released in pre-print versions in February.

The publications, which have since gone through peer review and include additional analyses and conclusions, virtually eliminate alternative scenarios that have been suggested as origins of the pandemic. Moreover, the authors conclude that the first spread to humans from animals likely occurred in two separate transmission events in the Huanan market in late November 2019.

One study – “The Huanan Seafood Wholesale Market in Wuhan was the early epicenter of the COVID-19 pandemic” - scrutinized the locations of the first known COVID-19 cases, as well as swab samples taken from surfaces at various locations at the market. The other – “The molecular epidemiology of multiple zoonotic origins of SARS-CoV-2” - focused on genomic sequences of SARS-CoV-2 from samples collected from COVID-19 patients during the first weeks of the pandemic in China.

Along with Suchard, a physician who also teaches at the David Geffen School of Medicine at UCLA, UCLA post-doctoral scholars Andrew Magee and Karthik Gangavarapu co-authored this work.

The first paper examined the geographic pattern of COVID-19 cases in the first month of the outbreak, December 2019. The team was able to determine the locations of almost all of the 174 COVID-19 cases identified by the World Health Organization that month, 155 of which were in Wuhan.

Analyses showed that these cases were clustered tightly around the Huanan market, whereas later cases were dispersed widely throughout Wuhan – a city of 11 million people. Notably, the researchers found that a striking percentage of early COVID patients with no known connection to the market – meaning they neither worked there nor shopped there – turned out to live close-by.

Part 1

Comment by Dr. Krishna Kumari Challa on July 29, 2022 at 11:50am

To demonstrate the ability of their battery to run low-power electronics, the authors combined two cells into one battery and used it to power an alarm clock with a liquid crystal display. Analysis of the performance of a one-cell battery revealed that after two drops of water were added, the battery activated within 20 seconds and, when not connected to an energy-consuming device, reached a stable voltage of 1.2 volts. The voltage of a standard AA alkaline battery is 1.5 volts. After one hour, the one-cell battery's performance decreased significantly due to the paper drying. However, after two more drops of water were added, it maintained a stable operating voltage of 0.5 volts for more than one additional hour.

The authors propose that the biodegradability of paper and zinc could enable their battery to minimize the environmental impact of disposable, low-power electronics. They suggest that the sustainability of the battery can be further increased by minimizing the amount of zinc used within the ink, which also allows the amount of electricity the battery generates to be precisely controlled.

Gustav Nyström, Water activated disposable paper battery, Scientific Reports (2022). DOI: 10.1038/s41598-022-15900-5. www.nature.com/articles/s41598-022-15900-5

Part 2

**

Comment by Dr. Krishna Kumari Challa on July 29, 2022 at 11:49am

Just add water to activate a disposable paper battery

A water-activated disposable paper battery is presented in a proof-of-principle study in Scientific Reports. The authors suggest that it could be used to power a wide range of low-power, single-use disposable electronics—such as smart labels for tracking objects, environmental sensors and medical diagnostic devices—and minimize their environmental impact. The battery, devised by Gustav Nyström and colleagues, is made of at least one cell measuring one centimeter squared and consisting of three inks printed onto a rectangular strip of paper. Sodium chloride salt is dispersed throughout the strip of paper and one of its shorter ends has been dipped in wax. An ink containing graphite flakes, which acts as the positive end of the battery (cathode), is printed onto one of the flat sides of the paper while an ink containing zinc powder, which acts as the negative end of the battery (anode), is printed onto the reverse side of the paper. Additionally, an ink containing graphite flakes and carbon black is printed on both sides of the paper, on top of the other two inks. This ink connects the positive and negative ends of the battery to two wires, which are located at the wax-dipped end of the paper. When a small amount of water is added, the salts within the paper dissolve and charged ions are released. These ions activate the battery by dispersing through the paper, resulting in zinc in the ink at the negative end of the battery releasing electrons. Attaching the wires to an electrical device closes the circuit so that electrons can be transferred from the negative end—via the graphite and carbon black-containing ink, wires and device—to the positive end (the graphite-containing ink) where they are transferred to oxygen in the surrounding air. These reactions generate an electrical current that can be used to power the device.

Part 1

Comment by Dr. Krishna Kumari Challa on July 29, 2022 at 11:44am

Promising evidence of deuterium forming into a metallic state at high pressure

A trio of researchers at the French Alternative Energies and Atomic Energy Commission has shown promising evidence of deuterium forming into a metallic state at high pressure. In their paper published in the journal Physical Review Letters, researchers describe the process they used to pressurize a deuterium sample and test it for a transition state. Theory suggests that all elements should transition to a metallic state if subjected to strong enough pressure. This is because at some point, their electrons will become delocalized. But modeling, much less demonstrating, such transition points has proven to be difficult. Early research looking for the transition state of hydrogen led to theories that it would reach a metallic state when hydrogen molecules disassociated completely. That led to many efforts to see if such theories were true—sadly, none were successful. Then in 2000, a team at Cornell University calculated that hydrogen should transition at 410 GPa. In 2020, the researchers of the current study used a diamond anvil cell to compress a sample of hydrogen to 425 GPa and used synchrotron infrared absorption and Raman spectroscopy to measure the band gap of the material. They found a sudden drop from 0.6eV to 0.1eV at 80K, comprising promising evidence of hydrogen forming into a metallic state as theorized. A short time later, physicist Alexander Goncharov suggested that transitions should happen more easily under conditions where quantum motion could allow for some atoms to tunnel from one place to another. Noting that deuterium nuclei are heavier than hydrogen, the researchers reasoned that they should be less delocalized than protons and thus should require more pressure to transition. To find out if that was the case, the team reran their 2020 effort, only this time, they used deuterium instead of hydrogen. They found the band gap decreased in ways similar to the hydrogen experiment, but it did so at 460 GPa, possibly confirming the theory. The researchers noted that they also saw nothing that would indicate molecular disassociation had occurred in either experiment.

Paul Loubeyre et al, Compression of D2 to 460 GPa and Isotopic Effects in the Path to Metal Hydrogen, Physical Review Letters (2022). DOI: 10.1103/PhysRevLett.129.035501

**

Comment by Dr. Krishna Kumari Challa on July 29, 2022 at 11:30am

Alarm as Earth hits 'Overshoot Day' Thursday: NGOs

Mankind marks a dubious milestone Thursday (yesterday), the day by which humanity has consumed all earth can sustainably produce for this year, with NGOS warning the rest of 2022 will be lived in resource deficit.

The date—dubbed "Earth Overshoot Day"—marks a tipping point when people have used up "all that ecosystems can regenerate in one year", according to the Global Footprint Network and WWF.

From January 1 to July 28, humanity has used as much from nature as the planet can renew in the entire year. That's why this July 28 is Earth Overshoot Day.

The Earth has a lot of stock, so we can deplete Earth for some time but we cannot overuse it for ever. It's like with money; we can spend more than we earn for some time until we're broke."

It would take 1.75 Earths to provide for the world's population in a sustainable way, according to the measure, which was created by researchers in the early 1990s.

Global Footprint Network said Earth Overshoot Day has fallen ever sooner over the last 50 years.

Source: News Agencies

Comment by Dr. Krishna Kumari Challa on July 29, 2022 at 11:19am

Engineers develop stickers that can see inside the body

Ultrasound imaging is a safe and noninvasive window into the body's workings, providing clinicians with live images of a patient's internal organs. To capture these images, trained technicians manipulate ultrasound wands and probes to direct sound waves into the body. These waves reflect back out to produce high-resolution images of a patient's heart, lungs, and other deep organs.

Currently, ultrasound imaging requires bulky and specialized equipment available only in hospitals and doctor's offices. But a new design by MIT engineers might make the technology as wearable and accessible as buying Band-Aids at the pharmacy.

In a paper appearing recently in Science, the engineers present the design for a new ultrasound sticker—a stamp-sized device that sticks to skin and can provide continuous ultrasound imaging of internal organs for 48 hours.

The researchers applied the stickers to volunteers and showed the devices produced live, high-resolution images of major blood vessels and deeper organs such as the heart, lungs, and stomach. The stickers maintained a strong adhesion and captured changes in underlying organs as volunteers performed various activities, including sitting, standing, jogging, and biking.

The current design requires connecting the stickers to instruments that translate the reflected sound waves into images. The researchers point out that even in their current form, the stickers could have immediate applications: For instance, the devices could be applied to patients in the hospital, similar to heart-monitoring EKG stickers, and could continuously image internal organs without requiring a technician to hold a probe in place for long periods of time.

If the devices can be made to operate wirelessly—a goal the team is currently working toward—the ultrasound stickers could be made into wearable imaging products that patients could take home from a doctor's office or even buy at a pharmacy.

Chonghe Wang et al, Bioadhesive ultrasound for long-term continuous imaging of diverse organs, Science (2022). DOI: 10.1126/science.abo2542. www.science.org/doi/10.1126/science.abo2542

Philip Tan et al, Seeing inside a body in motion, Science (2022). DOI: 10.1126/science.adc8732. www.science.org/doi/10.1126/science.adc8732

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