Earth

2.5 Billion T. Rex Inhabited the Planet, Researchers Say (axios.com) 46

For the first time, scientists have estimated how many Tyrannosaurus rex, the so-called king of dinosaurs, once roamed the Earth. From a report: The number is staggering: 2.5 billion Tyrannosaurus rex lived and died during the roughly 2.4 million years the species survived on the planet, according to a new study set to be published in the journal Science on Friday. The study may help contextualize the fossil record and the rarity of finding certain fossilized prehistoric organisms, according to lead researcher Charles Marshall, director of the University of California Museum of Paleontology. "I mean, to me, it's just amazing we could have come up with a number," Marshall told Axios. "Some people have asked me, 'How does your number compare to other numbers of the total that have ever lived?' The answer is it doesn't because there weren't any."
Medicine

Pfizer CEO Says Third Covid Vaccine Dose Likely Needed Within 12 Months (cnbc.com) 408

Pfizer CEO Albert Bourla said people will "likely" need a booster dose of a Covid-19 vaccine within 12 months of getting fully vaccinated. His comments were made public Thursday but were taped April 1. From a report: Bourla said it's possible people will need to get vaccinated against the coronavirus annually. "A likely scenario is that there will be likely a need for a third dose, somewhere between six and 12 months and then from there, there will be an annual revaccination, but all of that needs to be confirmed. And again, the variants will play a key role," he told CNBC's Bertha Coombs during an event with CVS Health. "It is extremely important to suppress the pool of people that can be susceptible to the virus," Bourla said. The comment comes after Johnson & Johnson CEO Alex Gorsky told CNBC in February that people may need to get vaccinated against Covid-19 annually, just like seasonal flu shots. Researchers still don't know how long protection against the virus lasts once someone has been fully vaccinated.
Medicine

99.992% of Fully Vaccinated People Have Dodged COVID, CDC Data Shows (arstechnica.com) 143

An anonymous reader quotes a report from Ars Technica: Cases of COVID-19 are extremely rare among people who are fully vaccinated, according to a new data analysis by the Centers for Disease Control and Prevention. Among more than 75 million fully vaccinated people in the US, just around 5,800 people reported a "breakthrough" infection, in which they became infected with the pandemic coronavirus despite being fully vaccinated. The numbers suggest that breakthroughs occur at the teeny rate of less than 0.008 percent of fully vaccinated people -- and that over 99.992 percent of those vaccinated have not contracted a SARS-CoV-2 infection.

The figures come from a nationwide database that the CDC set up to keep track of breakthrough infections and monitor for any concerning signs that the breakthroughs may be clustering by patient demographics, geographic location, time since vaccination, vaccine type, or vaccine lot number. The agency will also be keeping a close eye on any breakthrough infections that are caused by SARS-CoV-2 variants, some of which have been shown to knock back vaccine efficacy. [...] The extraordinary calculation that 99.992 percent of vaccinated people have not contracted the virus may reflect that they all simply have not been exposed to the virus since being vaccinated. Also, there are likely cases missed in reporting. Still, the data is a heartening sign.
As for the "breakthroughs," the agency says many of them occurred in older people, who are more vulnerable to COVID-19. There are some scattered through every age group, but more than 40 percent were in people ages 60 and above.

"We see [breakthroughs] with all vaccines," top infectious disease expert Anthony Fauci said in a press briefing earlier this week. "No vaccine is 100 percent efficacious or effective, which means that you will always see breakthrough infections regardless of the efficacy of your vaccine."
Communications

California To Hunt Greenhouse Gas Leaks and Superemitters With Monitoring Satellites (sciencemag.org) 101

California and its partners are set to launch by 2023 two satellites to spot and monitor plumes of planet-warming carbon dioxide (CO2) and methane. "If all goes right, dozens more could follow," reports Science Magazine. From the report: The $100 million Carbon Mapper project, announced today and financed by private philanthropists including Michael Bloomberg, will advance efforts to track concentrated emissions of greenhouse gases, which rise from fossil fuel power plants, leaky pipelines, and abandoned wells. Previous satellites have lacked the resolution and focus to monitor point sources rigorously. [...] The satellites will be built and managed by Planet, a California company that already operates a constellation of Earth-imaging satellites. The spacecraft will rely on "hyperspectral" imaging spectrometers developed by NASA's Jet Propulsion Laboratory (JPL). Rather than gathering light in just a few discrete wavelength channels, like the human eye, these spectrometers capture reflected sunlight and subdivide it into more than 400 wavelength channels across the visible and into the infrared. The intensity of light across these channels can be tied to specific chemistries and reflect the abundances of certain gases in the air molecules below.

The satellites won't just measure gases in the air; they will also detect chemical signatures on the ground. By measuring the intensity of green chlorophyll or detecting the signatures for excess salts or fungus, for example, researchers will be able to evaluate the health of crops and forests. They can prospect for minerals in remote regions. They can map and identify different coral and algae species, and they can track dust and soot. Even snow and ice pops out in these sensors, says Robert Green, a remote-sensing scientist at JPL. "Snow is one of the most colorful materials on Earth if you look beyond visible light."

The first two Carbon Mapper satellites will each be roughly the size of a washing machine, weighing up to 200 kilograms. They will provide imagery with a resolution of 30 meters but won't offer global coverage at first. Instead, they will target regions known to host superemitters, like power plants, oil and gas drilling, or livestock operations. The regions will be revisited every few weeks to start. All emission data, calculated from the plume intensity and length, will be made publicly available -- in the hopes that governments and businesses will do more to staunch leaks and tamp down discharges. [...] Should Carbon Mapper's first two satellites prove successful, Planet envisions building a commercial constellation of similar satellites that would revisit every spot on the planet once a day, and selling those data to regulators and companies.

Medicine

Respiratory Study Launches To Discover How Apple Watch Can Predict COVID-19 6

Researchers at the University of Washington have partnered with Apple to study how Apple Watch may be used to predict illnesses such as coronavirus, or flu. Apple Insider reports: "The goal of the study is to see if the information collected by the Apple Watch and iPhone can detect early signs of respiratory illnesses like COVID-19," say the organizers on the recruitment page. The study is focusing on the Seattle area because residents "may have higher than normal risk of respiratory illness because of frequent exposure to other people through work or other activities, health conditions, or other factors."

This Apple Respiratory Study is expected to take "up to six months." During the study, participants will be required to periodically answer survey questions in the Apple Research iPhone app. If participants get sick while enrolled in the study, they will be sent an in-home testing kit for COVID-19 and other respiratory illnesses. But, this will likely assist the study further, as sick participants will be asked to "take some additional health measurements using your Apple Watch."
Mars

What Happens When You Have a Heart Attack on the Way To Mars? (wired.co.uk) 70

If your heart stops en route to Mars, rest assured that researchers have considered how to carry out CPR in space. (One option is to plant your feet on the ceiling and extend your arms downwards to compress the patient's chest.) From a report: Astronauts, because of their age range and high physical fitness, are unlikely to suffer a stroke or have their appendix suddenly explode. That's good because, if it does happen, they're in the realm of what Jonathan Scott -- head of the medical projects and technology team at the European Space Agency -- describes as 'treatment futility.' In other words: there's nothing anyone can do about it. On the ISS, when medical incidents arise, astronauts can draw on the combined expertise of a host of medical experts at Nasa. "The patient is on the space station, the doctor is on the ground, and if there's a problem the patient consults the doctor," says Scott. By the time astronauts reach Mars, there'll be a 40-minute time lag in communications, if it's possible to make contact at all. "We have to begin preparing for not only being able to diagnose things in spaceflight but also to treat them as well," Scott says.

Artificial intelligence is likely to be a part of the solution. If you're imagining the holographic doctor from Star Trek, downgrade your expectations, at least for the next few decades. Kris Lehnhardt, the element scientist for exploration medical capability at Nasa, says: "We are many, many, many years away from: please state the nature of the medical emergency." Emmanuel Urquieta is deputy chief scientist at the Translational Institute for Space Health (TRISH), a Nasa-funded program which conducts research into healthcare for deep space missions. While full AI may be a way off, Urquieta believes some form of artificial intelligence will still play a crucial role. "It's going to be essential for a mission to Mars," he says. While the crew for a mission to Mars will likely include a medical doctor, he explains: "No single physician can know everything." And, of course: "What happens if that astronaut gets sick?" Research projects funded by TRISH include Butterfly iQ, a handheld ultrasound device for use by non-medical personnel to make diagnoses that would otherwise require bulky equipment and a trained operator. VisualDx is an AI diagnostics tool originally developed to analyse images and identify skin conditions. The technology is now being adapted to help astronauts diagnose a wide range of conditions most commonly encountered in space, without an internet connection.

Science

Genetic Mistakes That Could Shape Our Species (bbc.com) 92

Slashdot reader omfglearntoplay shares an excerpt from a BBC article that explores the new technologies that may have already introduced genetic errors to the human gene pool. The article starts by mentioning He Jiankui, a Shenzhen researcher who was sentenced to prison in late 2019 for creating the world's first genetically altered babies. From the report: Jiankui had made the first genetically modified babies in the history of humankind. After 3.7 billion years of continuous, undisturbed evolution by natural selection, a life form had taken its innate biology into its own hands. The result was twin baby girls who were born with altered copies of a gene known as CCR5, which the scientist hoped would make them immune to HIV. But things were not as they seemed. In the years since, it's become clear that Jiankui's project was not quite as innocent as it might sound. He had broken laws, forged documents, misled the babies' parents about any risks and failed to do adequate safety testing. However, arguably the biggest twist were the mistakes. It turns out that the babies involved, Lulu and Nana, have not been gifted with neatly edited genes after all. Not only are they not necessarily immune to HIV, they have been accidentally endowed with versions of CCR5 that are entirely made up -- they likely do not exist in any other human genome on the planet. And yet, such changes are heritable -- they could be passed on to their children, and children's children, and so on.

In fact, there have been no shortage of surprises in the field. From the rabbits altered to be leaner that inexplicably ended up with much longer tongues to the cattle tweaked to lack horns that were inadvertently endowed with a long stretch of bacterial DNA in their genomes (including some genes that confer antibiotic resistance, no less) -- its past is riddled with errors and misunderstandings. More recently, researchers at the Francis Crick Institute in London warned that editing the genetics of human embryos can lead to unintended consequences. By analyzing data from previous experiments, they found that approximately 16% had accidental mutations that would not have been picked up via standard tests. Why are these mistakes so common? Can they be overcome? And how could they affect future generations?

Science

Researchers Create Light Waves That Can Penetrate Even Opaque Materials (phys.org) 38

fahrbot-bot shares a report from Phys.Org: Why is sugar not transparent? Because light that penetrates a piece of sugar is scattered, altered and deflected in a highly complicated way. However, as a research team from TU Wien (Vienna) and Utrecht University (Netherlands) has now been able to show, there is a class of very special light waves for which this does not apply: for any specific disordered medium -- such as the sugar cube you may just have put in your coffee -- tailor-made light beams can be constructed that are practically not changed by this medium, but only attenuated. The light beam penetrates the medium, and a light pattern arrives on the other side that has the same shape as if the medium were not there at all. This idea of "scattering-invariant modes of light" can also be used to specifically examine the interior of objects. The results have now been published in the journal Nature Photonics. This method of finding light patterns that penetrate an object largely undisturbed could also be used for imaging procedures. "In hospitals, X-rays are used to look inside the body -- they have a shorter wavelength and can therefore penetrate our skin. But the way a light wave penetrates an object depends not only on the wavelength, but also on the waveform," says Matthias Kuhmayer, who works as a Ph.D. student on computer simulations of wave propagation. "If you want to focus light inside an object at certain points, then our method opens up completely new possibilities. We were able to show that using our approach the light distribution inside the zinc oxide layer can also be specifically controlled."
Science

Human Taste Buds Can Tell the Difference Between Normal and 'Heavy' Water, Study Finds (sciencealert.com) 104

An anonymous reader quotes a report from ScienceAlert: [T]here's been a longstanding question over whether heavy water tastes the same as regular drinking water -- or whether its subtle isotopic variation yields a different taste that people may be able to perceive. "There is anecdotal evidence from the 1930s that the taste of pure D2O is distinct from the neutral one of pure H2O, being described mostly as 'sweet,'" an international team of researchers led by first authors and biochemists Natalie Ben Abu and Philip E. Mason explains in a new study. [I]n their new research, Ben Abu, Mason, and their team can finally confirm that there really is something a bit different about the taste of heavy water. "Despite the fact that the two isotopes are nominally chemically identical, we have shown conclusively that humans can distinguish by taste (which is based on chemical sensing) between H2O and D2O, with the latter having a distinct sweet taste," explains senior author and physical chemist Pavel Jungwirth from the Czech Academy of Sciences.

In a taste-testing experiment with 28 participants, most people were able to distinguish between H2O and D2O, and tests with mixed amounts of the waters revealed that greater proportions of heavy water were perceived as tasting sweeter. In tests with mice, however, the animals did not seem to prefer drinking heavy water over regular water, although they did show a preference for sugared water -- suggesting that in mice, D2O does not elicit the same sweet taste that people can perceive. Other taste tests conducted by the team suggest why this is so, indicating that human taste receptivity to D2O is mediated by the taste receptor TAS1R2/TAS1R3, which is known to respond to sweetness in both natural sugars and artificial sweeteners. Experiments in the lab with HEK 293 cells confirmed the same thing, showing robust responses in TAS1R2/TAS1R3 expressing cells when exposed to D2O.
The findings are published in the journal Communications Biology.
Space

Remembering Yuri Gagarin, the First Man in Space (space.com) 97

Sixty years ago today, Yuri Gagarin became the first human ever in space.

Space.com reports: Because no one was certain how weightlessness would affect a pilot, the spherical capsule had little in the way of onboard controls; the work was done either automatically or from the ground. If an emergency arose, Gagarin was supposed to receive an override code that would allow him to take manual control, but Sergei Korolev, chief designer of the Soviet space program, disregarded protocol and gave the code to the pilot prior to the flight.

Over the course of 108 minutes, Vostok 1 traveled around the Earth once, reaching a maximum height of 203 miles (327 kilometers). The spacecraft carried 10 days' worth of provisions in case the engines failed and Gagarin was required to wait for the orbit to naturally decay. But the supplies were unnecessary. Gagarin re-entered Earth's atmosphere, managing to maintain consciousness as he experienced forces up to eight times the pull of gravity during his descent.

The BBC remembers how on his return to earth, Gagarin parachuted into some farmland several hundred miles from Moscow — "much to the surprise of a five-year-old girl who was out in the fields planting potatoes."

60 years later, the BBC tracked down and interviewed Interviewed that woman — who still remembered Gagarin's kind voice and smile. (Thanks to Slashdot reader 4wdloop for sharing the article.)

The BBC also published a look at Gagarin's global fame in the years that followed — and Phys.org notes that even today, there are few people more universally admired in Russia than Yuri Gagarin: His smiling face adorns murals across the country. He stands, arms at his sides as if zooming into space, on a pedestal 42.5 metres (140 feet) above the traffic flowing on Moscow's Leninsky Avenue. He is even a favourite subject of tattoos... The anniversary of Gagarin's historic flight on April 12, 1961 — celebrated every year in Russia as Cosmonautics Day — sees Russians of all ages lay flowers at monuments to his accomplishment across the country...

Gagarin, says historian Alexander Zheleznyakov, was a figure who helped fuel the imagination. "He transformed us from a simple biological species to one that could imagine an entire universe beyond Earth."

Biotech

How a Researcher 'Clinging To the Fringes of Academia' Helped Develop a Covid-19 Vaccine (nytimes.com) 64

Long-time Slashdot reader destinyland writes: The New York Times tells the story of Hungarian-born Dr. Kariko, whose father was a butcher and who growing up had never met a scientist — but knew they wanted to be one. Despite earning a Ph.D. at Hungary's University of Szeged and working as a postdoctoral fellow at its Biological Research Center, Kariko never found a permanent position after moving to the U.S., "instead clinging to the fringes of academia."

Now 66 years old, Dr. Kariko is suddenly being hailed as "one of the heroes of Covid-19 vaccine development," after spending an entire career focused on mRNA, "convinced mRNA could be used to instruct cells to make their own medicines, including vaccines."

From the article: For many years her career at the University of Pennsylvania was fragile. She migrated from lab to lab, relying on one senior scientist after another to take her in. She never made more than $60,000 a year... She needed grants to pursue ideas that seemed wild and fanciful. She did not get them, even as more mundane research was rewarded. "When your idea is against the conventional wisdom that makes sense to the star chamber, it is very hard to break out," said Dr. David Langer, a neurosurgeon who has worked with Dr. Kariko... Kariko's husband, Bela Francia, manager of an apartment complex, once calculated that her endless workdays meant she was earning about a dollar an hour.
The Times also describes a formative experience in 1989 with cardiologist Elliot Barnathan: One fateful day, the two scientists hovered over a dot-matrix printer in a narrow room at the end of a long hall. A gamma counter, needed to track the radioactive molecule, was attached to a printer. It began to spew data.

Their detector had found new proteins produced by cells that were never supposed to make them — suggesting that mRNA could be used to direct any cell to make any protein, at will.

"I felt like a god," Dr. Kariko recalled.

Yet Kariko was eventually left without a lab or funds for research, until a chance meeting at a photocopying machine led to a partnership with Dr. Drew Weissman of the University of Pennsylvania: "We both started writing grants," Dr. Weissman said. "We didn't get most of them. People were not interested in mRNA. The people who reviewed the grants said mRNA will not be a good therapeutic, so don't bother.'" Leading scientific journals rejected their work. When the research finally was published, in Immunity, it got little attention... "We talked to pharmaceutical companies and venture capitalists. No one cared," Dr. Weissman said. "We were screaming a lot, but no one would listen."

Eventually, though, two biotech companies took notice of the work: Moderna, in the United States, and BioNTech, in Germany. Pfizer partnered with BioNTech, and the two now help fund Dr. Weissman's lab.

Space

Astronomers Detect a Bright-Blue Bridge of Stars, and It's About To Blow (livescience.com) 28

"Astrophysicists have found a new region of the Milky Way, and it's filled with searingly hot, bright-blue stars that are about to explode," writes Live Science (in a report shared by long-time Slashdot reader fahrbot-bot): The researchers were creating the most detailed map yet of the star-flecked spiral arms of our galactic neighborhood with the European Space Agency's (ESA) Gaia telescope when they discovered the region, which they have named the Cepheus spur, they reported in a new study.

Nestled between the Orion Arm — where our solar system is — and the constellation Perseus, the spur is a belt between two spiral arms filled with enormous stars three times the size of the sun and colored blue by their blistering heat. Astronomers call these giant, blue stars OB stars due to the predominantly blue wavelengths of light that they emit. They are the rarest, hottest, shortest-living and largest stars in the entire galaxy. The violent nuclear reactions taking place inside their hearts make them six times hotter than the sun. And the enormous stellar explosions that end their lives — called supernovas — scatter the heavy elements essential for complex life far into the galaxy.

"OB stars are rare, in a Galaxy of 400 billion stars there might be less than 200,000," study co-author Michelangelo Pantaleoni González, a researcher at the Spanish Astrobiology Center (CAB), told Live Science.

Mars

NASA's Mars Helicopter Flight Postponed to No Earlier than This Wednesday (nasa.gov) 16

An anonymous reader shares this announcement from NASA: Based on data from the Ingenuity Mars helicopter that arrived late Friday night, NASA has chosen to reschedule the Ingenuity Mars Helicopter's first experimental flight to no earlier than April 14 [this Wednesday].

During a high-speed spin test of the rotors on Friday, the command sequence controlling the test ended early due to a "watchdog" timer expiration. This occurred as it was trying to transition the flight computer from 'Pre-Flight' to 'Flight' mode. The helicopter is safe and healthy and communicated its full telemetry set to Earth.

The watchdog timer oversees the command sequence and alerts the system to any potential issues. It helps the system stay safe by not proceeding if an issue is observed and worked as planned.

The helicopter team is reviewing telemetry to diagnose and understand the issue. Following that, they will reschedule the full-speed test.

Earth

Melting Ice Sheets Triggered 60 Feet of Sea Level Rise 14,600 Years Ago (phys.org) 100

"New research has found that previous ice loss events could have caused sea-level rise at rates of around 3.6 meters per century, offering vital clues as to what lies ahead should climate change continue unabated," reports Phys.org: A team of scientists, led by researchers from Durham University, used geological records of past sea levels to shed light on the ice sheets responsible for a rapid pulse of sea-level rise in Earth's recent past. Geological records tell us that, at the end of the last ice age around 14,600 years ago, sea levels rose at ten times the current rate due to Meltwater Pulse 1A (MWP-1A); a 500 year, ~18 meter sea-level rise event... The new study uses detailed geological sea-level data and state-of-the-art modelling techniques to reveal the sources... Interestingly, most of the meltwater appears to have originated from the former North American and Eurasian ice sheets, with minimal contribution from Antarctica, reconciling formerly disparate views...

The results are important for our understanding of ice-ocean-climate interactions which play a significant role in shaping terrestrial weather patterns. The findings are particularly timely with the Greenland ice sheet rapidly melting, contributing to a rise in sea levels and changes to global ocean circulation... Lead author Yucheng Lin, in the Department of Geography at Durham University notes, "The next big question is to work out what triggered the ice melt, and what impact the massive influx of meltwater had on ocean currents in the North Atlantic. This is very much on our minds today — any disruption to the Gulf Stream, for example due to melting of the Greenland Ice Sheet, will have significant consequences for the UK climate."

Biotech

Scientists Connect Human Brain To Computer Wirelessly For First Time Ever (thenextweb.com) 18

"Scientists have demonstrated the first human use of a wireless brain-computer interface, a potential breakthrough for people with paralysis," reports The Next Web (in a story shared by Slashdot reader Hmmmmmm): While traditional BCIs are tethered to users via cables, the new system — called BrainGate — replaces the cords with a small transmitter affixed atop a users' head. The unit then connects to an electrode array implanted in the brain's motor cortex. In a clinical trial, two participants with paralysis used the system to point, click, and type on a standard tablet computer. They both achieved similar typing speeds and point-and-click accuracy as those attained with wired systems.

The researchers say it's the first time a device has transmitted the full spectrum of signals recorded by a sensor in the brain's motor cortex.

Science

Scientists Dive Into Axolotl Genome, Looking For Secrets To Regeneration (gizmodo.com) 24

An anonymous reader quotes a report from Gizmodo: Its adorableness aside, the Mexican axolotl is a salamander of particular interest to scientists. On the molecular level, the animal seems to have a cheat code for life: It can regenerate its limbs and vital organs, an ability researchers are desperate to better understand for medical applications. Now, geneticists have gotten a clearer view of the smiling salamander's genome, rendering it on the chromosomal scale. The research was published this week in the Proceedings of the National Academy of Sciences. Understanding a genetic structure in complete detail takes a lot of time, far longer than it takes to first report the mapping of a genome, as we did with humans in 2003 and the duck-billed platypus in 2008. Secrets remain shrouded in those purportedly finished genetic codes, so geneticists keep tinkering. Decrypting the axolotl's genome in particular was a tall order; where bits of a human genome charged with making a protein may span hundreds to thousands of base pairs, in an axolotl, it takes hundreds of thousands of base pairs. Nevertheless, the complete axolotl genome was announced in 2019 by the same team who published the recent research.

The recent paper specifically looked at how the genome is folded away inside the animal on the molecular level and where the DNA sequences that regulate genes are located in relation to the places where gene transcription starts. That's remarkable when you consider the scale and extreme compactness of the folding; a human DNA strand is about 6 feet when stretched out, but an axolotl's would be over 30 feet. All that genetic material is being sequestered in the cells of an animal 200 times smaller than the average human -- it's a mind-boggling example of efficiency in packing, all on a microscopic scale.
Why it matters: The research will be important for seeing if the ability to regenerate could ever be activated in humans.

"The work has ordered the sequenced pieces of axolotl genomic DNA sequence in the correct order, as it is on the chromosome," Elly Tanaka, a biochemist at the Vienna BioCenter's Institute of Molecular Pathology, said in an email. "This is important because, in all animals with vertebrae, genes are turned on and off by control sequences that are actually lying pretty far away from the gene itself."
Science

Glass Molded Like Plastic Could Usher In New Era of Complex Glass Shapes (sciencemag.org) 41

sciencehabit shares a report from Science Magazine: The production of glass -- one of humanity's oldest materials -- is getting a 21st century makeover. A new approach to glassmaking treats the material like plastic, allowing scientists to injection mold vaccine vials, sinuous channels for carrying out lab chemistry, and other complex shapes.

The scientists created a printable powder by mixing silica nanoparticles with a polymer that could be cured with ultraviolet (UV) light. After printing the shapes they wanted, they cured the polymer with UV light so it would hold its shape. They then fired the mix in an oven to burn off the polymer and fuse the silica particles into a continuous glass structure. The approach worked, making it possible to craft shapes such as tiny pretzels and replica castle gates. The work garnered interest from companies wanting to build minute lenses and other complex transparent optical components for telecommunications equipment. But the procedure was slow, turning out components one by one, rather than a fully industrial approach that could produce parts en masse, as is done with plastic.

To speed things up, [the researchers] have now extended their nanocomposite approach to work with injection molding, a process used to mass produce plastic parts like toys and car bumpers by the ton. The researchers again started with tiny silica particles. The team then mixed the silica with two polymers, polyethylene glycol (PEG) and polyvinyl butyral (PVB). The mixture created a dry powder with the consistency of toothpaste. The team fed the paste into an extruder that pressed it into a preformed mold with shapes such as a disc or tiny gear. To harden them, the researchers used water to wash away the PEG. They then fired the remaining material in two stages: First at 600C to burn out the PVB, and second at 1300C to fuse the silica particles into the final piece. Outside of the mold, the parts hold their shape because myriad weak attractive bonds, called van der Waals interactions, form between neighboring silica particles. But the parts are still fragile.
The report has been published in the journal Science.
Science

New, Reversible CRISPR Method Can Control Gene Expression While Leaving DNA Sequence Unchanged (phys.org) 20

fahrbot-bot shares a report from Phys.Org: Over the past decade, the CRISPR-Cas9 gene editing system has revolutionized genetic engineering, allowing scientists to make targeted changes to organisms' DNA. While the system could potentially be useful in treating a variety of diseases, CRISPR-Cas9 editing involves cutting DNA strands, leading to permanent changes to the cell's genetic material. Now, in a paper published online in Cell on April 9, researchers describe a new gene editing technology called CRISPRoff that allows researchers to control gene expression with high specificity while leaving the sequence of the DNA unchanged.

The classic CRISPR-Cas9 system uses a DNA-cutting protein called Cas9 found in bacterial immune systems. The system can be targeted to specific genes in human cells using a single guide RNA, where the Cas9 proteins create tiny breaks in the DNA strand. Then the cell's existing repair machinery patches up the holes. Because these methods alter the underlying DNA sequence, they are permanent.

That's where the researchers saw an opportunity for a different kind of gene editor -- one that didn't alter the DNA sequences themselves, but changed the way they were read in the cell. This sort of modification is what scientists call 'epigenetic' -- genes may be silenced or activated based on chemical changes to the DNA strand. Epigenetic gene silencing often works through methylation -- the addition of chemical tags to to certain places in the DNA strand -- which causes the DNA to become inaccessible to RNA polymerase, the enzyme which reads the genetic information in the DNA sequence into messenger RNA transcripts, which can ultimately be the blueprints for proteins. With this new CRISPRoff technology, one can [express a protein briefly] to write a program that's remembered and carried out indefinitely by the cell.

Science

Are You Confused by Scientific Jargon? So Are Scientists (nytimes.com) 53

Scientific papers containing lots of specialized terminology are less likely to be cited by other researchers. The New York Times reports: Polje, nappe, vuggy, psammite. Some scientists who study caves might not bat an eye, but for the rest of us, these terms might as well be ancient Greek. Specialized terminology isn't unique to the ivory tower -- just ask a baker about torting or an arborist about bracts, for example. But it's pervasive in academia, and now a team of researchers has analyzed jargon in a set of over 21,000 scientific manuscripts. They found that papers containing higher proportions of jargon in their titles and abstracts were cited less frequently by other researchers. Science communication -- with the public but also among scientists -- suffers when a research paper is packed with too much specialized terminology, the team concluded. These results were published Wednesday in Proceedings of the Royal Society B.

Jargon can be a problem, but it also serves a purpose, said Hillary Shulman, a communications scientist at Ohio State University. "As our ideas become more refined, it makes sense that our concepts do too." This language-within-a-language can be a timesaver, a way to precisely convey meaning, she said. However, it also runs the risk of starkly reminding people -- even some well-educated researchers -- that they aren't "in the know." "It's alienating," said Dr. Shulman.

Science

Studies That Add Human Cells To Animal Brains Are Ethical, Panel Says (sciencemag.org) 50

sciencehabit shares a report from Science Magazine: Experiments that create tiny brainlike structures from human stem cells or transplant human cells into an animal's brain have made some scientists, ethicists, and religious leaders uneasy in recent years. And the National Institutes of Health (NIH) has restricted some of this research. Now, a U.S. scientific panel has weighed in with advice about how to oversee this controversial and fast-moving area of neuroscience. The panel finds little evidence that brain "organoids" or animals given human cells experience humanlike consciousness or pain, and concludes current rules are adequate for overseeing this work. But they caution that could change, particularly as experiments move into nonhuman primates. "The rationale for the report is to get out ahead of the curve," says Harvard University neuroscientist Joshua Sanes, co-chair of the National Academies of Sciences, Engineering, and Medicine committee that released its report today.

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