Science – Page 31

It’s increasingly unlikely that humans will fly around the Moon next year

artemis II, ground systems, orion, Science, Space / Tim Belzer / October 17, 2024

Don’t book your tickets for the launch of NASA’s Artemis II mission next year just yet.

We have had reason to doubt the official September 2025 launch date for the mission, the first crewed flight into deep space in more than five decades, for a while now. This is principally because NASA is continuing to mull the implications of damage to the Orion spacecraft’s heat shield from the Artemis I mission nearly two years ago.

However, it turns out that there are now other problems with holding to this date as well.

No schedule margin

A new report from the US Government Accountability Office found that NASA’s Exploration Ground Systems program—this is, essentially, the office at Kennedy Space Center in Florida responsible for building ground infrastructure to support the Space Launch System rocket and Orion—is in danger of missing its schedule for Artemis II.

During this flight a crew of four astronauts, commanded by NASA’s Reid Wiseman, will launch inside Orion on a 10-day mission out to the Moon and back. The spacecraft will follow a free-return trajectory, which is important, because if there is a significant problem with Orion spacecraft’s propulsion system, the trajectory of the vehicle will still carry it back to Earth. At their closest approach, the crew will come within about 6,500 miles (10,400 km) of the surface of the far side of the Moon.

The new report, published Thursday, finds that the Exploration Ground Systems program had several months of schedule margin in its work toward a September 2025 launch date at the beginning of the year. But now, the program has allocated all of that margin to technical issues experienced during work on the rocket’s mobile launcher and pad testing.

“Earlier in 2024, the program was reserving that time for technical issues that may arise during testing of the integrated SLS and Orion vehicle or if weather interferes with planned activities, among other things,” the report states. “Officials said it is likely that issues will arise because this is the first time testing many of these systems. Given the lack of margin, if further issues arise during testing or integration, there will likely be delays to the September 2025 Artemis II launch date.”

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There’s another massive meat recall over Listeria—and it’s a doozy

health, Science / Rejus Almole / October 16, 2024

Another nationwide meat recall is underway over Listeria contamination—and its far more formidable than the last.

As of October 15, meat supplier BrucePac, of Durant, Oklahoma, is recalling 11.8 million pounds of ready-to-eat meat and poultry products after routine federal safety testing found Listeria monocytogenes, a potentially deadly bacterium, in samples of the company’s poultry. The finding triggered an immediate recall, which was first issued on October 9. But, officials are still working to understand the extent of the contamination—and struggling to identify the hundreds of potentially contaminated products.

“Because we sell to other companies who resell, repackage, or use our products as ingredients in other foods, we do not have a list of retail products that contain our recalled items,” BrucePac said in a statement updated October 15.

Depending on the packaging, the products may have establishment numbers 51205 or P-51205 inside or under the USDA mark of inspection. But, for now, consumers’ best chance of determining whether they’ve purchased any of the affected products is to look through a 342-page list of products identified by the US Department of Agriculture so far.

The unorganized document lists fresh and frozen foods sold at common retailers, including 7-Eleven, Aldi, Amazon Fresh, Giant Eagle, Kroger, Target, Trader Joe’s, Walmart, and Wegmans. Affected products carry well-known brand names, such as Atkins, Boston Market, Dole, Fresh Express, Jenny Craig, Michelina’s, Taylor Farms, and stores’ brands, such as Target’s Good & Gather. The recalled products were made between May 31, 2024 and October 8, 2024.

In the latest update, the USDA noted that some of the recalled products were also distributed to schools, but the agency hasn’t identified the schools that received the products. Restaurants and other institutions also received the products.

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Amazon joins Google in investing in small modular nuclear power

Amazon, AWS, Biz & IT, carbon emissions, Energy, nuclear energy, Science, small modular nuclear reactors / Rejus Almole / October 16, 2024

Small nukes is good nukes?

What’s with the sudden interest in nuclear power among tech titans?

Diagram of a reactor and its coolant system. There are two main components, the reactor itself, which has a top-to-bottom flow of fuel pellets, and the boiler, which receives hot gas from the reactor and uses it to boil water.

Fuel pellets flow down the reactor (left), as gas transfer heat to a boiler (right). Credit: X-energy

On Tuesday, Google announced that it had made a power purchase agreement for electricity generated by a small modular nuclear reactor design that hasn’t even received regulatory approval yet. Today, it’s Amazon’s turn. The company’s Amazon Web Services (AWS) group has announced three different investments, including one targeting a different startup that has its own design for small, modular nuclear reactors—one that has not yet received regulatory approval.

Unlike Google’s deal, which is a commitment to purchase power should the reactors ever be completed, Amazon will lay out some money upfront as part of the agreements. We’ll take a look at the deals and technology that Amazon is backing before analyzing why companies are taking a risk on unproven technologies.

Money for utilities and a startup

Two of Amazon’s deals are with utilities that serve areas where it already has a significant data center footprint. One of these is Energy Northwest, which is an energy supplier that sends power to utilities in the Pacific Northwest. Amazon is putting up the money for Energy Northwest to study the feasibility of adding small modular reactors to its Columbia Generating Station, which currently houses a single, large reactor. In return, Amazon will get the right to purchase power from an initial installation of four small modular reactors. The site could potentially support additional reactors, which Energy Northwest would be able to use to meet demands from other users.

The deal with Virginia’s Dominion Energy is similar in that it would focus on adding small modular reactors to Dominion’s existing North Anna Nuclear Generating Station. But the exact nature of the deal is a bit harder to understand. Dominion says the companies will “jointly explore innovative ways to advance SMR development and financing while also mitigating potential cost and development risks.”

Should either or both of these projects go forward, the reactor designs used will come from a company called X-energy, which is involved in the third deal Amazon is announcing. In this case, it’s a straightforward investment in the company, although the exact dollar amount is unclear (the company says Amazon is “anchoring” a $500 million round of investments). The money will help finalize the company’s reactor design and push it through the regulatory approval process.

Small modular nuclear reactors

X-energy is one of several startups attempting to develop small modular nuclear reactors. The reactors all have a few features that are expected to help them avoid the massive time and cost overruns associated with the construction of large nuclear power stations. In these small reactors, the limited size allows them to be made at a central facility and then be shipped to the power station for installation. This limits the scale of the infrastructure that needs to be built in place and allows the assembly facility to benefit from economies of scale.

This also allows a great deal of flexibility at the installation site, as you can scale the facility to power needs simply by adjusting the number of installed reactors. If demand rises in the future, you can simply install a few more.

The small modular reactors are also typically designed to be inherently safe. Should the site lose power or control over the hardware, the reactor will default to a state where it can’t generate enough heat to melt down or damage its containment. There are various approaches to achieving this.

X-energy’s technology is based on small, self-contained fuel pellets called TRISO particles for TRi-structural ISOtropic. These contain both the uranium fuel and a graphite moderator and are surrounded by a ceramic shell. They’re structured so that there isn’t sufficient uranium present to generate temperatures that can damage the ceramic, ensuring that the nuclear fuel will always remain contained.

The design is meant to run at high temperatures and extract heat from the reactor using helium, which is used to boil water and generate electricity. Each reactor can produce 80 megawatts of electricity, and the reactors are designed to work efficiently as a set of four, creating a 320 MW power plant. As of yet, however, there are no working examples of this reactor, and the design hasn’t been approved by the Nuclear Regulatory Commission.

Why now?

Why is there such sudden interest in small modular reactors among the tech community? It comes down to growing needs and a lack of good alternatives, even given the highly risky nature of the startups that hope to build the reactors.

It’s no secret that data centers require enormous amounts of energy, and the sudden popularity of AI threatens to raise that demand considerably. Renewables, as the cheapest source of power on the market, would be one way of satisfying that growth, but they’re not ideal. For one thing, the intermittent nature of the power they supply, while possible to manage at the grid level, is a bad match for the around-the-clock demands of data centers.

The US has also benefitted from over a decade of efficiency gains keeping demand flat despite population and economic growth. This has meant that all the renewables we’ve installed have displaced fossil fuel generation, helping keep carbon emissions in check. Should newly installed renewables instead end up servicing rising demand, it will make it considerably more difficult for many states to reach their climate goals.

Finally, renewable installations have often been built in areas without dedicated high-capacity grid connections, resulting in a large and growing backlog of projects (2.6 TW of generation and storage as of 2023) that are stalled as they wait for the grid to catch up. Expanding the pace of renewable installation can’t meet rising server farm demand if the power can’t be brought to where the servers are.

These new projects avoid that problem because they’re targeting sites that already have large reactors and grid connections to use the electricity generated there.

In some ways, it would be preferable to build more of these large reactors based on proven technologies. But not in two very important ways: time and money. The last reactor completed in the US was at the Vogtle site in Georgia, which started construction in 2009 but only went online this year. Costs also increased from $14 billion to over $35 billion during construction. It’s clear that any similar projects would start generating far too late to meet the near-immediate needs of server farms and would be nearly impossible to justify economically.

This leaves small modular nuclear reactors as the least-bad option in a set of bad options. Despite many startups having entered the space over a decade ago, there is still just a single reactor design approved in the US, that of NuScale. But the first planned installation saw the price of the power it would sell rise to the point where it was no longer economically viable due to the plunge in the cost of renewable power; it was canceled last year as the utilities that would have bought the power pulled out.

The probability that a different company will manage to get a reactor design approved, move to construction, and manage to get something built before the end of the decade is extremely low. The chance that it will be able to sell power at a competitive price is also very low, though that may change if demand rises sufficiently. So the fact that Amazon is making some extremely risky investments indicates just how worried it is about its future power needs. Of course, when your annual gross profit is over $250 billion a year, you can afford to take some risks.

John is Ars Technica’s science editor. He has a Bachelor of Arts in Biochemistry from Columbia University, and a Ph.D. in Molecular and Cell Biology from the University of California, Berkeley. When physically separated from his keyboard, he tends to seek out a bicycle, or a scenic location for communing with his hiking boots.

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Drugmakers can keep making off-brand weight-loss drugs as FDA backpedals

compounding pharmacies, diabetes, fda, GLP-1, health, lilly, mounjaro, OFA, outsourcing facilities, Science, Tirzepatide, weight loss, zepbound / Kris Guyer / October 15, 2024

The judge in the case, District Judge Mark Pittman, granted the FDA’s request, canceling an October 15 hearing, and ordering the parties to submit a joint status report on November 21.

Drugmakers respond

The move was celebrated by the Outsourcing Facilities Association (OFA), which filed the lawsuit.

“We believe that this is a fair resolution in light of the agency’s rash decision to take the drug off of the list at a time when the agency has acknowledged ‘supply disruptions,’ which immediately created a major access issue for patients everywhere,” OFA Chairperson Lee Rosebush said in a statement. “Most important, should the FDA repeat its removal decision when a shortage still genuinely exists, we will return to court.”

The move is also likely to please patients who have come to rely on cheaper, more readily available compounded versions of the drugs. For some, compounded products may have been their only access to tirzepatide. Still, those drugs are not without risk. The FDA has repeatedly emphasized that compounded drugs are not FDA-approved and do not go through the same safety, efficacy, and quality reviews. And the agency has warned of dosing errors and other safety concerns with compounded versions.

The one party that is certainly unhappy with the FDA’s move is Eli Lilly, which had reportedly sent cease-and-desist letters to compounders. In an emailed statement to Ars, a spokesperson for Lilly said that there was sufficient supply of the company’s drug and continued use of compounded versions is unwarranted. “Nothing changes the fact that, as FDA has recognized, Mounjaro and Zepbound are available and the shortage remains ‘resolved,'” the spokesperson said.

Lilly also noted the FDA’s safety concerns about the compounded versions, adding that its own examination of some compounded products found impurities, bacteria, strange coloring, incorrect potency, puzzling chemical structures, and, in one case, a product that was just sugar alcohol.

“All doses of Lilly’s FDA-approved medicines are available and it is important that patients not be exposed to the risks in taking untested, unapproved knockoffs,” the spokesperson said.

In terms of the supply “disruptions” the FDA mentioned and that some patients and pharmacies have reportedly experienced, Lilly said that the supply chain was complex and there are many reasons why a given pharmacy may not have a specific dose at hand, such as limited refrigerated storage space.

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Sustainable building effort reaches new heights with wooden skyscrapers

Science, skyscraper, syndication, wood science / Paul Patrick / October 15, 2024

Wood offers architects an alternative to carbon-intensive steel and concrete.

At the University of Toronto, just across the street from the football stadium, workers are putting up a 14-story building with space for classrooms and faculty offices. What’s unusual is how they’re building it — by bolting together giant beams, columns, and panels made of manufactured slabs of wood.

As each wood element is delivered by flatbed, a tall crane lifts it into place and holds it in position while workers attach it with metal connectors. In its half-finished state, the building resembles flat-pack furniture in the process of being assembled.

The tower uses a new technology called mass timber. In this kind of construction, massive, manufactured wood elements that can extend more than half the length of a football field replace steel beams and concrete. Though still relatively uncommon, it is growing in popularity and beginning to pop up in skylines around the world.

A photo of a modern apartment interior with wooden beams, floor and ceiling. Windows overlook the surrounding neighborhood. — Mass timber can lend warmth and beauty to an interior. Pictured is a unit in the eight-story Carbon12 condominium in Portland, Oregon. Credit: KAISER + PATH

Today, the tallest mass timber building is the 25-story Ascent skyscraper in Milwaukee, completed in 2022. As of that year, there were 84 mass timber buildings eight stories or higher either built or under construction worldwide, with another 55 proposed. Seventy percent of the existing and future buildings were in Europe, about 20 percent in North America, and the rest in Australia and Asia, according to a report from the Council on Tall Buildings and Urban Habitat. When you include smaller buildings, at least 1,700 mass timber buildings had been constructed in the United States alone as of 2023.

Mass timber is an appealing alternative to energy-intensive concrete and steel, which together account for almost 15 percent of global carbon dioxide emissions. Though experts are still debating mass timber’s role in fighting climate change, many are betting it’s better for the environment than current approaches to construction. It relies on wood, after all, a renewable resource.

Mass timber also offers a different aesthetic that can make a building feel special. “People get sick and tired of steel and concrete,” says Ted Kesik, a building scientist at the University of Toronto’s Mass Timber Institute, which promotes mass timber research and development. With its warm, soothing appearance and natural variations, timber can be more visually pleasing. “People actually enjoy looking at wood.”

Same wood, stronger structure

Using wood for big buildings isn’t new, of course. Industrialization in the 18th and 19th centuries led to a demand for large factories and warehouses, which were often “brick and beam” construction—a frame of heavy wooden beams supporting exterior brick walls.

As buildings became ever taller, though, builders turned to concrete and steel for support. Wood construction became mostly limited to houses and other small buildings made from the standard-sized “dimensional” lumber you see stacked at Home Depot.

But about 30 years ago, builders in Germany and Austria began experimenting with techniques for making massive wood elements out of this readily available lumber. They used nails, dowels and glue to combine smaller pieces of wood into big, strong and solid masses that don’t require cutting down large old-growth trees.

Engineers including Julius Natterer, a German engineer based in Switzerland, pioneered new methods for building with the materials. And architects including Austria’s Hermann Kaufmann began gaining attention for mass timber projects, including the Ölzbündt apartments in Austria, completed in 1997, and Brock Commons, an 18-story student residence at the University of British Columbia, completed in 2017.

In principle, mass timber is like plywood but on a much larger scale: The smaller pieces are layered and glued together under pressure in large specialized presses. Today, beams up to 50 meters long, usually made of what’s called glue-laminated timber, or glulam, can replace steel elements. Panels up to 50 centimeters thick, typically cross-laminated timber, or CLT, replace concrete for walls and floors.

These wood composites can be surprisingly strong—stronger than steel by weight. But a mass timber element must be bulkier to achieve that same strength. As a building gets higher, the wooden supports must get thicker; at some point, they simply take up too much space. So for taller mass timber buildings, including the Ascent skyscraper, architects often turn to a combination of wood, steel and concrete.

Historically, one of the most obvious concerns with using mass timber for tall buildings was fire safety. Until recently, many building codes limited wood construction to low-rise buildings.

Though they don’t have to be completely fireproof, buildings need to resist collapse long enough to give firefighters a chance to bring the flames under control, and for occupants to get out. Materials used in conventional skyscrapers, for instance, are required to maintain their integrity in a fire for three hours or more.

To demonstrate mass timber’s fire resistance, engineers put the wood elements in gas-fired chambers and monitor their integrity. Other tests set fire to mock-ups of mass timber buildings and record the results.

These tests have gradually convinced regulators and customers that mass timber can resist burning long enough to be fire-safe. That’s partly because a layer of char tends to form early on the outside of the timber, insulating the interior from much of the fire’s heat.

Mass timber got a major stamp of approval in 2021, when the International Code Council changed the International Building Code, which serves as a model for jurisdictions around the world, to allow mass timber construction up to 18 stories tall. With this change, more and more localities are expected to update their codes to routinely allow tall mass timber buildings, rather than requiring them to get special approvals.

There are other challenges, though. “Moisture is the real problem, not fire,” says Steffen Lehmann, an architect and scholar of urban sustainability at the University of Nevada, Las Vegas.

All buildings must control moisture, but it’s absolutely crucial for mass timber. Wet wood is vulnerable to deterioration from fungus and insects like termites. Builders are careful to prevent the wood from getting wet during transportation and construction, and they deploy a comprehensive moisture management plan, including designing heat and ventilation systems to keep moisture from accumulating. For extra protection from insects, wood can be treated with chemical pesticides or surrounded by mesh or other physical barriers where it meets the ground.

Another problem is acoustics, since wood transmits sound so well. Designers use sound insulation materials, leave space between walls and install raised floors, among other methods.

Potential upsides of mass timber

Combating global warming means reducing greenhouse gas emissions from the building sector, which is responsible for 39 percent of emissions globally. Diana Ürge-Vorsatz, an environmental scientist at the Central European University in Vienna, says mass timber and other bio-based materials could be an important part of that effort.

In a 2020 paper in the Annual Review of Environment and Resources, she and colleagues cite an estimate from the lumber industry that the 18-story Brock Commons, in British Columbia, avoided the equivalent of 2,432 metric tons of CO₂ emissions compared with a similar building of concrete and steel. Of those savings, 679 tons came from the fact that less greenhouse gas emissions are generated in the manufacture of wood versus concrete and steel. Another 1,753 metric tons of CO₂ equivalent were locked away in the building’s wood.

“If you use bio-based material, we have a double win,” Ürge-Vorsatz says.

But a lot of the current enthusiasm over mass timber’s climate benefits is based on some big assumptions. The accounting often assumes, for instance, that any wood used in a mass timber building will be replaced by the growth of new trees, and that those new trees will take the same amount of CO₂ out of the atmosphere across time. But if old-growth trees are replaced with new tree plantations, the new trees may never reach the same size as the original trees, some environmental groups argue. There are also concerns that increasing demand for wood could lead to more deforestation and less land for food production.

Studies also tend to assume that once the wood is in a building, the carbon is locked up for good. But not all the wood from a felled tree ends up in the finished product. Branches, roots and lumber mill waste may decompose or get burned. And when the building is torn down, if the wood ends up in a landfill, the carbon can find its way out in the form of methane and other emissions.

“A lot of architects are scratching their heads,” says Stephanie Carlisle, an architect and environmental researcher at the nonprofit Carbon Leadership Forum, wondering whether mass timber always has a net benefit. “Is that real?” She believes climate benefits do exist. But she says understanding the extent of those benefits will require more research.

In the meantime, mass timber is at the forefront of a whole different model of construction called integrated design. In traditional construction, an architect designs a building first and then multiple firms are hired to handle different parts of the construction, from laying the foundation, to building the frame, to installing the ventilation system, and so on.

In integrated design, says Kesik, the design phase is much more detailed and involves the various firms from the beginning. The way different components will fit and work together is figured out in advance. Exact sizes and shapes of elements are predetermined, and holes can even be pre-drilled for attachment points. That means many of the components can be manufactured off-site, often with advanced computer-controlled machinery.

A lot of architects like this because it gives them more control over the building elements. And because so much of the work is done in advance, the buildings tend to go up faster on-site — up to 40 percent faster than other buildings, Lehmann says.

Mass timber buildings tend to be manufactured more like automobiles, Kesik says, with all the separate pieces shipped to a final location for assembly. “When the mass timber building shows up on-site, it’s really just like an oversized piece of Ikea furniture,” he says. “Everything sort of goes together.”

This story originally appeared in Knowable Magazine.

Knowable Magazine explores the real-world significance of scholarly work through a journalistic lens.

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What do planet formation and badminton have in common?

astronomy, astrophysics, badminton, dust, planet-forming disk, planetary formation, protoplanetary disks, Science / Mike M. / October 15, 2024

It might not come as a surprise to learn that Lin is a badminton player. “The experience of playing badminton is really the thing that kick-started the idea and led me to ask the right questions,” he said.

Previous explanations attribute the dust alignment to the magnetic influence of the central star, the physics of which can be complicated and not always intuitive. The beauty of the proposed birdie mechanism is its simplicity. “It’s a very good first step,” said Bing Ren, an astronomer at France’s Côte d’Azur Observatory who wasn’t involved in the study.

Still, the birdie-alignment hypothesis is just that—a hypothesis. To confirm whether it holds water, scientists will need to throw their full observational arsenal at protoplanetary disks, such as viewing them at different wavelengths, to sniff out the finer details of particle-gas interactions.

Tracing invisible gas

Real-life protoplanetary disks are likely more complicated than a uniform squadron of space potatoes suspended in thin air. Ren suspects that the grains come in various shapes, sizes, and speeds. Nevertheless, he says Lin’s study is a good foundation for computer models of interstellar clouds, onto which scientists can tack layers of complexity.

The new research points a way forward for probing protoplanetary disks, particularly gas behavior. Given that the grains trace the gas direction, studying dust organization using existing tools like polarized light can allow scientists to map a disk’s aerodynamic flow. Essentially, these grains are tiny flags that signal where the wind blows.

As granular as the details are, the dust alignment is a small but key step in a grand journey of particle-to-planet progression. The nitty-gritty of a particle’s conduct will determine its fate for millions of years—perhaps the primordial seed will hoover up hydrogen and helium to become a gas giant or amass dust to transform into a terrestrial world like Earth. It all starts with it flailing or keeping steady amid a sea of other specks.

Monthly Notices of the Royal Astronomical Society, 2024. DOI: 10.1093/mnras/stae2248 (About DOIs)

Shi En Kim is a DC-based freelance journalist who writes about health, the environment, technology, and the physical sciences. She and three other journalists founded Sequencer Magazine in early 2024. Occasionally, she creates art to accompany her writings or does it simply for fun. Follow her on Twitter at @goes_by_kim, or see more of her work on her personal website.

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Routine dental X-rays are not backed by evidence—experts want it to stop

bitewings, cavities, dentistry, dentists, health, radiation, Science, X-rays / Rejus Almole / October 14, 2024

The actual recommendations might surprise you—along with the state of modern dentistry.

An expert looking at a dental X-ray and saying “look at that unnecessary X-ray,” probably. Credit: Getty | MilanEXPO

Has your dentist ever told you that it’s recommended to get routine dental X-rays every year? My (former) dentist’s office did this year—in writing, even. And they claimed that the recommendation came from the American Dental Association.

It’s a common refrain from dentists, but it’s false. The American Dental Association does not recommend annual routine X-rays. And this is not new; it’s been that way for well over a decade.

The association’s guidelines from 2012 recommended that adults who don’t have an increased risk of dental caries (myself included) need only bitewing X-rays of the back teeth every two to three years. Even people with a higher risk of caries can go as long as 18 months between bitewings. The guidelines also note that X-rays should not be preemptively used to look for problems: “Radiographic screening for the purpose of detecting disease before clinical examination should not be performed,” the guidelines read. In other words, dentists are supposed to examine your teeth before they take any X-rays.

But, of course, the 2012 guidelines are outdated—the latest ones go further. In updated guidance published in April, the ADA doesn’t recommend any specific time window for X-rays at all. Rather, it emphasizes that patient exposure to X-rays should be minimized, and any X-rays should be clinically justified.

There’s a good chance you’re surprised. Dentistry’s overuse of X-rays is a problem dentists do not appear eager to discuss—and would likely prefer to skirt. My former dentist declined to comment for this article, for example. And other dentists have been doing that for years. Nevertheless, the problem is well-established. A New York Times article from 2016, titled “You Probably Don’t Need Dental X-Rays Every Year,” quoted a dental expert noting the exact problem:

“Many patients of all ages receive bitewing X-rays far more frequently than necessary or recommended. And adults in good dental health can go a decade between full-mouth X-rays.”

Data is lacking

The problem has bubbled up again in a series of commentary pieces published in JAMA Internal Medicine today. The pieces were all sparked by a viewpoint that Ars reported on in May, in which three dental and health experts highlighted that many routine aspects of dentistry, including biannual cleanings, are not evidence-based and that the industry is rife with overdiagnosis and overtreatment. That viewpoint, titled “Too Much Dentistry,” also appeared in JAMA Internal Medicine.

The new pieces take a more specific aim at dental radiography. But, as in the May viewpoint, experts also blasted dentistry more generally for being out of step with modern medicine in its lack of data to support its practices—practices that continue amid financial incentives to overtreat and little oversight to stop it, they note.

In a piece titled “Too Much Dental Radiography,” Sheila Feit, a retired medical expert based in New York, pointed out that using X-rays for dental screenings is not backed by evidence. “Data are lacking about outcomes,” she wrote. If anything, the weak data we have makes it look ineffective. For instance, a 2021 systemic review of 77 studies that included data on a total of 15,518 tooth sites or surfaces found that using X-rays to detect early tooth decay led to a high degree of false-negative results. In other words, it led to missed cases.

Feit called for gold-standard randomized clinical trials to evaluate the risks and benefits of X-ray screenings for patients, particularly adults at low risk of caries. “Financial aspects of dental radiography also deserve further study,” Feit added. Overall, Feit called the May viewpoint “a timely call for evidence to support or refute common clinical dental practices.”

Dentistry without oversight

In a response published simultaneously in JAMA Internal Medicine, oral medicine expert Yehuda Zadik championed Feit’s point, calling it “an essential discussion about the necessity and risks of routine dental radiography, emphasizing once again the need for evidence-based dental care.”

Zadik, a professor of dental medicine at The Hebrew University of Jerusalem, noted that the overuse of radiography in dentistry is a global problem, one aided by dentistry’s unique delivery:

“Dentistry is among the few remaining health care professions where clinical examination, diagnostic testing including radiographs, diagnosis, treatment planning, and treatment are all performed in place, often by the same care practitioner” Zadik wrote. “This model of care delivery prevents external oversight of the entire process.”

While routine X-rays continue at short intervals, Zadik notes that current data “favor the reduction of patient exposure to diagnostic radiation in dentistry,” while advancements in dentistry dictate that X-rays should be used at “longer intervals and based on clinical suspicion.”

Though the digital dental X-rays often used today provide smaller doses of radiation than the film X-rays used in the past, radiation’s harms are cumulative. Zadik emphasizes that with the primary tenet of medicine being “First, do no harm,” any unnecessary X-ray is an unnecessary harm. Further, other technology can sometimes be used instead of radiography, including electronic apex locators for root canal procedures.

“Just as it is now unimaginable that, in the past, shoe fittings for children were conducted using X-rays, in the future it will be equally astonishing to learn that the fit of dental crowns was assessed using radiographic imaging,” Zadik wrote.

X-rays do more harm than good in children

Feit’s commentary also prompted a reply from the three authors of the original May viewpoint: Paulo Nadanovsky, Ana Paula Pires dos Santos, and David Nunan. The three followed up on Feit’s point that data is weak on whether X-rays are useful for detecting early decay, specifically white spot lesions. The experts raise the damning point that even if dental X-rays were shown to be good at doing that, there’s still no evidence that that’s good for patients.

“[T]here is no evidence that detecting white spot lesions, with or without radiographs, benefits patients,” the researchers wrote. “Most of these lesions do not progress into dentine cavities,” and there’s no evidence that early treatments make a difference in the long run.

To bolster the point, the three note that data from children suggest that X-ray screening does more harm than good. In a randomized clinical trial published in 2021, 216 preschool children were split into two groups: one that received only a visual-tactile dental exam, while the others received both a visual-tactile exam and X-rays. The study found that adding X-rays caused more harm than benefit because the X-rays led to false positives and overdiagnosis of cavitated caries needing restorative treatment. The authors of the trial concluded that “visual inspection should be conducted alone in regular clinical practice.”

Like Zadik, the three researchers note that screenings for decay and cavities are not the only questionable use of X-rays in dental practice. Other common dental and orthodontic treatments involving radiography—practices often used in children and teens—might also be unnecessary harms. They raise the argument against the preventive removal of wisdom teeth, which is also not backed by evidence.

Like Feit, the three researchers reiterate the call for well-designed trials to back up or refute common dental practices.

Beth is Ars Technica’s Senior Health Reporter. Beth has a Ph.D. in microbiology from the University of North Carolina at Chapel Hill and attended the Science Communication program at the University of California, Santa Cruz. She specializes in covering infectious diseases, public health, and microbes.

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People think they already know everything they need to make decisions

belief formation, cognitive biases, Human behavior, misinformation, Science / Rejus Almole / October 14, 2024

The obvious difference was the decisions they made. In the group that had read the article biased in favor of merging the schools, nearly 90 percent favored the merger. In the group that had read the article that was biased by including only information in favor of keeping the schools separate, less than a quarter favored the merger.

The other half of the experimental population wasn’t given the survey immediately. Instead, they were given the article that they hadn’t read—the one that favored the opposite position of the article that they were initially given. You can view this group as doing the same reading as the control group, just doing so successively rather than in a single go. In any case, this group’s responses looked a lot like the control’s, with people roughly evenly split between merger and separation. And they became less confident in their decision.

It’s not too late to change your mind

There is one bit of good news about this. When initially forming hypotheses about the behavior they expected to see, Gehlbach, Robinson, and Fletcher suggested that people would remain committed to their initial opinions even after being exposed to a more complete picture. However, there was no evidence of this sort of stubbornness in these experiments. Instead, once people were given all the potential pros and cons of the options, they acted as if they had that information the whole time.

But that shouldn’t obscure the fact that there’s a strong cognitive bias at play here. “Because people assume they have adequate information, they enter judgment and decision-making processes with less humility and more confidence than they might if they were worrying whether they knew the whole story or not,” Gehlbach, Robinson, and Fletcher.

This is especially problematic in the current media environment. Many outlets have been created with the clear intent of exposing their viewers to only a partial view of the facts—or, in a number of cases, the apparent intent of spreading misinformation. The new work clearly indicates that these efforts can have a powerful effect on beliefs, even if accurate information is available from various sources.

PLOS ONE, 2024. DOI: 10.1371/journal.pone.0310216 (About DOIs).

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Can walls of oysters protect shores against hurricanes? Darpa wants to know.

climate change, coastal erosion, hurricanes, Science, sea level, syndication / Tim Belzer / October 13, 2024

Colonized artificial reef structures could absorb the power of storms.

picture of some shoreline

Credit: Kemter/Getty Images

On October 10, 2018, Tyndall Air Force Base on the Gulf of Mexico—a pillar of American air superiority—found itself under aerial attack. Hurricane Michael, first spotted as a Category 2 storm off the Florida coast, unexpectedly hulked up to a Category 5. Sustained winds of 155 miles per hour whipped into the base, flinging power poles, flipping F-22s, and totaling more than 200 buildings. The sole saving grace: Despite sitting on a peninsula, Tyndall avoided flood damage. Michael’s 9- to 14-foot storm surge swamped other parts of Florida. Tyndall’s main defense was luck.

That $5 billion disaster at Tyndall was just one of a mounting number of extreme-weather events that convinced the US Department of Defense that it needed new ideas to protect the 1,700 coastal bases it’s responsible for globally. As hurricanes Helene and Milton have just shown, beachfront residents face compounding threats from climate change, and the Pentagon is no exception. Rising oceans are chewing away the shore. Stronger storms are more capable of flooding land.

In response, Tyndall will later this month test a new way to protect shorelines from intensified waves and storm surges: a prototype artificial reef, designed by a team led by Rutgers University scientists. The 50-meter-wide array, made up of three chevron-shaped structures each weighing about 46,000 pounds, can take 70 percent of the oomph out of waves, according to tests. But this isn’t your grandaddy’s seawall. It’s specifically designed to be colonized by oysters, some of nature’s most effective wave-killers.

If researchers can optimize these creatures to work in tandem with new artificial structures placed at sea, they believe the resulting barriers can take 90 percent of the energy out of waves. David Bushek, who directs the Haskin Shellfish Research Laboratory at Rutgers, swears he’s not hoping for a megastorm to come and show what his team’s unit is made of. But he’s not not hoping for one. “Models are always imperfect. They’re always a replica of something,” he says. “They’re not the real thing.”

Playing defense Reefense

The project is one of three being developed under a $67.6 million program launched by the US government’s Defense Advanced Research Projects Agency, or Darpa. Cheekily called Reefense, the initiative is the Pentagon’s effort to test if “hybrid” reefs, combining manmade structures with oysters or corals, can perform as well as a good ol’ seawall. Darpa chose three research teams, all led by US universities, in 2022. After two years of intensive research and development, their prototypes are starting to go into the water, with Rutgers’ first up.

Today, the Pentagon protects its coastal assets much as civilians do: by hardening them. Common approaches involve armoring the shore with retaining walls or arranging heavy objects, like rocks or concrete blocks, in long rows. But hardscape structures come with tradeoffs. They deflect rather than absorb wave energy, so protecting one’s own shoreline means exposing someone else’s. They’re also static: As sea levels rise and storms get stronger, it’s getting easier for water to surmount these structures. This wears them down faster and demands constant, expensive repairs.

In recent decades, a new idea has emerged: using nature as infrastructure. Restoring coastal habitats like marshes and mangroves, it turns out, helps hold off waves and storms. “Instead of armoring, you’re using nature’s natural capacity to absorb wave energy,” says Donna Marie Bilkovic, a professor at the Virginia Institute for Marine Science. Darpa is particularly interested in two creatures whose numbers have been decimated by humans but which are terrific wave-breakers when allowed to thrive: oysters and corals.

Oysters are effective wave-killers because of how they grow. The bivalves pile onto each other in large, sturdy mounds. The resulting structure, unlike a smooth seawall, is replete with nooks, crannies, and convolutions. When a wave strikes, its energy gets diffused into these gaps, and further spent on the jagged, complex surfaces of the oysters. Also unlike a seawall, an oyster wall can grow. Oysters have been shown to be capable of building vertically at a rate that matches sea-level rise—which suggests they’ll retain some protective value against higher tides and stronger storms.

Today hundreds of human-tended oyster reefs, particularly on America’s Atlantic coast, use these principles to protect the shore. They take diverse approaches; some look much like natural reefs, while others have an artificial component. Some cultivate oysters for food, with coastal protection a nice co-benefit; others are built specifically to preserve shorelines. What’s missing amid all this experimentation, says Bilkovic, is systematic performance data—the kind that could validate which approaches are most effective and cost-effective. “Right now the innovation is outpacing the science,” she says. “We need to have some type of systematic monitoring of projects, so we can better understand where the techniques work the best. There just isn’t funding, frankly.”

Hybrid deployments

Rather than wait for the data needed to engineer the perfect reef, Darpa wants to rapidly innovate them through a burst of R&D. Reefense has given awardees five years to deploy hybrid reefs that take up to 90 percent of the energy out of waves, without costing significantly more than traditional solutions. The manmade component should block waves immediately. But it should be quickly enhanced by organisms that build, in months or years, a living structure that would take nature decades.

The Rutgers team has built its prototype out of 788 interlocked concrete modules, each 2 feet wide and ranging in height from 1 to 2 feet tall. They have a scalloped appearance, with shelves jutting in all directions. Internally, all these shelves are connected by holes.

A Darpa-funded team will install sea barriers, made of hundreds of concrete modules, near a Florida military base. The scalloped shape should not only dissipate wave energy but invite oysters to build their own structures.

What this means is that when a wave strikes this structure, it smashes into the internal geometry, swirls around, and exits with less energy. This effect alone weakens the wave by 70 percent, according to the US Army Corps of Engineers, which tested a scale model in a wave simulator in Mississippi. But the effect should only improve as oysters colonize the structure. Bushek and his team have tried to design the shelves with the right hardness, texture, and shading to entice them.

But the reef’s value would be diminished if, say, disease were to wipe the mollusks out. This is why Darpa has tasked Rutgers with also engineering oysters resistant to dermo, a protozoan that’s dogged Atlantic oysters for decades. Darpa prohibited them using genetic-modification techniques. But thanks to recent advances in genomics, the Rutgers team can rapidly identify individual oysters with disease-resistant traits. It exposes these oysters to dermo in a lab, and crossbreeds the survivors, producing hardier mollusks. Traditionally it takes about three years to breed a generation of oysters for better disease resistance; Bushek says his team has done it in one.

The tropics are a different story

Oysters may suit the DoD’s needs in temperate waters, but for bases in tropical climates, it’s coral that builds the best seawalls. Hawaii, for instance, enjoys the protection of “fringing” coral reefs that extend offshore for hundreds of yards in a gentle slope along the seabed. The colossal, complex, and porous character of this surface exhausts wave energy over long distances, says Ben Jones, an oceanographer for the Applied Research Laboratory at the University of Hawaii—and head of the university’s Reefense project. He said it’s not unusual to see ocean swells of 6 to 8 feet way offshore, while the water at the seashore laps gently.

A Marine base in Hawaii will test out a new approach to coastal protection inspired by local coral reefs: A forward barrier will take the first blows of the waves, and a scattering of pyramids will further weaken waves before they get to shore.

Inspired by this effect, Jones and a team of researchers are designing an array that they’ll deploy near a US Marine Corps base in Oahu whose shoreline is rapidly receding. While the final design isn’t set yet, the broad strokes are: It will feature two 50-meter-wide barriers laid in rows, backed by 20 pyramid-like obstacles. All of these are hollow, thin-walled structures with sloping profiles and lots of big holes. Waves that crash into them will lose energy by crawling up the sides, but two design aspects of the structure—the width of the holes and the thinness of the walls—will generate turbulence in the water, causing it to spin off more energy as heat.

The manmade structures in Hawaii will be studded with concrete domes meant to encourage coral colonization. Though at grave risk from global warming, coral reefs are thought to provide coastal-protection benefits worth billions of dollars.

In the team’s full vision, the units are bolstered by about a thousand small coral colonies. Jones’ group plans to cover the structures with concrete modules that are about 20 inches in diameter. These have grooves and crevices that offer perfect shelters for coral larvae. The team will initially implant them with lab-bred coral. But they’re also experimenting with enticements, like light and sound, that help attract coral larvae from the wild—the better to build a wall that nature, not the Pentagon, will tend.

A third Reefense team, led by scientists at the University of Miami, takes its inspiration from a different sort of coral. Its design has a three-tiered structure. The foundation is made of long, hexagonal logs punctured with large holes; atop it is a dense layer with smaller holes—“imagine a sponge made of concrete,” says Andrew Baker, director of the university’s Coral Reef Futures Lab and the Reefense team lead.

The team thinks these artificial components will soak up plenty of wave energy—but it’s a crest of elkhorn coral at the top that will finish the job. Native to Florida, the Bahamas, and the Caribbean, elkhorn like to build dense reefs in shallow-water areas with high-intensity waves. They don’t mind getting whacked by water because it helps them harvest food; this whacking keeps wave energy from getting to shore.

Disease has ravaged Florida’s elkhorn populations in recent decades, and now ocean heat waves are dealing further damage. But their critical condition has also motivated policymakers to pursue options to save this iconic state species—including Baker’s, which is to develop an elkhorn more rugged against disease, higher temperatures, and nastier waves. Under Reefense, Baker says, his lab has developed elkhorn with 1.5° to 2° Celsius more heat tolerance than their ancestors. They also claim to have boosted the heat thresholds of symbiotic algae—an existentially important occupant of any healthy reef—and cross-bred local elkhorn with those from Honduras, where reefs have mysteriously withstood scorching waters.

An unexpected permitting issue, though, will force the Miami team to exit Reefense in 2025, without building the test unit it hoped to deploy near a Florida naval base. The federal permitting authority wanted a pot of money set aside to uninstall the structure if needed; Darpa felt it couldn’t do that in a timely way, according to Baker. (Darpa told WIRED every Reefense project has unique permitting challenges, so the Miami team’s fate doesn’t necessarily speak to anything broader. Representatives for the other two Reefense projects said Baker’s issue hasn’t come up for them.)

Though his team’s work with Reefense is coming to a premature end, Baker says, he’s confident their innovations will get deployed elsewhere. He’s been working with Key Biscayne, an island village near Miami whose shorelines have been chewed up by storms. Roland Samimy, the village’s chief resilience and sustainability officer, says they spend millions of dollars every few years importing sand for their rapidly receding beaches. He’s eager to see if a hybrid structure, like the University of Miami design, could offer protection at far lower cost. “People are realizing their manmade structures aren’t as resilient as nature is,” he says.

Not just Darpa

By no means is Darpa the only one experimenting in these areas. Around the world, there are efforts tackling various pieces of the puzzle, like breeding coral for greater heat resistance, or combining coral and oysters with artificial reefs, or designing low-carbon concrete that makes building these structures less environmentally damaging. Bilkovic, of the Virginia Institute for Marine Science, says Reefense will be a success if it demonstrates better ways of doing things than the prevailing methods—and has the data to back this up. “I’m looking forward to seeing what their findings are,” she says. “They’re systematically assessing the effectiveness of the project. Those lessons learned can be translated to other areas, and if the techniques are effective and work well, they can easily be translated to other regions.”

As for Darpa, though the Reefense prototypes are just starting to go in the water, the work is just beginning. All of these first-generation units will be scrutinized—both by the research teams and independent government auditors—to see whether their real-world performance matches what was in the models. Reefense is scheduled to conclude with a final report to the DoD in 2027. It won’t have a “winner” per se; as the Pentagon has bases around the world, it’s likely these three projects will all produce learnings that are relevant elsewhere.

Although their client has the largest military budget in the world, the three Reefense teams have been asked to keep an eye on the economics. Darpa has asked that project costs “not greatly exceed” those of conventional solutions, and tasked government monitors with checking the teams’ math. Catherine Campbell, Reefense’s program manager at Darpa, says affordability doesn’t just make it more likely the Pentagon will employ the technology—but that civilians can, too.

“This isn’t something bespoke for the military… we need to be in line with those kinds of cost metrics [in the civilian sector],” Campbell said in an email. “And that gives it potential for commercialization.”

This story originally appeared on wired.com.

Wired.com is your essential daily guide to what’s next, delivering the most original and complete take you’ll find anywhere on innovation’s impact on technology, science, business and culture.

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Starship is about to launch on its fifth flight, and this time there’s a catch

Commercial space, launch, Science, Space, spacex, Starbase, starship, texas / Paul Patrick / October 13, 2024

“We landed with half a centimeter accuracy in the ocean, so we think we have a reasonable chance to come back to the tower,” Gerstenmaier said.

Launch playbook

The Starship upper stage, meanwhile, will light six Raptor engines to accelerate to nearly orbital velocity, giving the rocket enough oomph to coast halfway around the world before falling back into the atmosphere over the Indian Ocean.

This is a similar trajectory to the one Starship flew in June, when it survived a fiery reentry for a controlled splashdown. It was the first time SpaceX completed an end-to-end Starship test flight. Onboard cameras showed fragments of the heat shield falling off Starship when it reentered the atmosphere, but the vehicle maintained control and reignited its Raptor engines, flipped from a horizontal to a vertical orientation, and settled into the Indian Ocean northwest of Australia.

After analyzing the results from the June mission, SpaceX engineers decided to rework the heat shield for the next Starship vehicle. The company said its technicians spent more than 12,000 hours replacing the entire thermal protection system with new-generation tiles, a backup ablative layer, and additional protections between the ship’s flap structures.

From start to finish, Sunday’s test flight should last approximately 1 hour and 5 minutes.

This diagram illustrates the path the Super Heavy booster will take to return to the launch pad in Texas, while the Starship upper stage continues the climb to space. Credit: SpaceX

Here’s an overview of the key events during Sunday’s flight:

• T+00: 00: 02: Liftoff

• T+00: 01: 02: Maximum aerodynamic pressure

• T+00: 02: 33: Super Heavy MECO (most engines cut off)

• T+00: 02: 41: Stage separation and ignition of Starship engines

• T+00: 02: 48: Super Heavy boost-back burn start

• T+00: 03: 41: Super Heavy boost-back burn shutdown

• T+00: 03: 43: Hot staging ring jettison

• T+00: 06: 08: Super Heavy is subsonic

• T+00: 06: 33: Super Heavy landing burn start

• T+00: 06: 56: Super Heavy landing burn shutdown and catch attempt

• T+00: 08: 27: Starship engine cutoff

• T+00: 48: 03: Starship reentry

• T+01: 02: 34: Starship is transonic

• T+01: 03: 43: Starship is subsonic

• T+01: 05: 15: Starship landing flip

• T+01: 05: 20: Starship landing burn

• T+01: 05: 34: Starship splashdown in Indian Ocean

SpaceX officials hope to see Starship’s heat shield stay intact as it dips into the atmosphere, when temperatures will reach 2,600° Fahrenheit (1,430° Celsius), hot enough to melt aluminum, the metal used to build many launch vehicles. SpaceX chose stainless steel for Starship because it strong at cryogenic temperatures—the rocket consumes super-cold fuel and oxidizer—and has a higher melting point than aluminum.

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Why a diabetes drug fell short of anticancer hopes

cancer treatment, experimental drugs, health, metformin, pharmaceutical research, Science, syndication / Tim Belzer / October 12, 2024

Studies suggested it could treat cancer, but the clinical trials were a bust.

Multi-pipettes

Pamela Goodwin has received hundreds of emails from patients asking if they should take a cheap, readily available drug, metformin, to treat their cancer.

It’s a fair question: Metformin, commonly used to treat diabetes, has been investigated for treating a range of cancer types in thousands of studies on laboratory cells, animals, and people. But Goodwin, an epidemiologist and medical oncologist treating breast cancer at the University of Toronto’s Mount Sinai Hospital, advises against it. No gold-standard trials have proved that metformin helps treat breast cancer—and her recent research suggests it doesn’t.

Metformin’s development was inspired by centuries of use of French lilac, or goat’s rue (Galega officinalis), for diabetes-like symptoms. In 1918, researchers discovered that a compound from the herb lowers blood sugar. Metformin, a chemical relative of that compound, has been a top type 2 diabetes treatment in the United States since it was approved in 1994. It’s cheap—less than a dollar per dose—and readily available, with few side effects. Today, more than 150 million people worldwide take the stuff.

Illustration of French lilac plant. — The French lilac, *Galega officinalis*, has been used medicinally since medieval times, including for symptoms associated with diabetes. Investigations of the plant’s chemical galegine led to the development of metformin, a related molecule synthesized in the lab. Credit: Wikimedia Commons

Metformin has a variety of effects, such as improving immune function and the body’s responses to insulin, which in turn regulates blood sugar. It can also slow growth of cancer cells in the lab. Many of these benefits seem to stem from metformin’s action in the cell’s powerhouses, the mitochondria, where it slows the production of energy and limits the generation of damaging chemicals called free radicals.

Researchers have considered metformin for treating a plethora of conditions, from glaucoma to polycystic ovary syndrome to pimples. “It really has a reputation of being a potential wonder drug,” says Michael Pollak, an oncologist and researcher at McGill University in Montreal. “There’s still a lot of work to be done on metformin.” (Pollak consults for biotechnology companies interested in metformin analogs as medicines.)

But the latest research has convinced Pollak and some others that treatment of cancers should be taken off the list.

More studies, but no proof

One of the first hints linking metformin to anticancer effects came in a short note in the British Medical Journal in 2005. Researchers analyzed medical records of almost 12,000 people from the Tayside region of Scotland who were newly diagnosed with diabetes between 1993 and 2001. Of those, more than 900 went on to develop cancer. Interestingly, those who’d taken metformin at some point during the study period were 23 percent less likely to have received a later cancer diagnosis.

This finding fueled further research on people with diabetes taking metformin and the risk for breast cancer, liver cancer, ovarian and endometrial cancer, and other types. The authors of a 2013 analysis, covering more than 1 million patients in 41 observational studies like the original one, concluded that metformin “might be associated with a significant reduction in the risk of cancer.” But such associations are not proof.

Researchers went on to explore the link in studies with cells in dishes and in lab animals, finding that metformin slowed growth of blood, breast, endometrial, lung, liver, stomach, and thyroid cancer cells. It also seemed to make cancer cells extra sensitive to chemotherapy drugs. In one mouse study, scientists grafted human breast, prostate, or lung cancer cells into the animals and treated them with either standard chemotherapy drugs, metformin, or a combination of both. The combination worked best, preventing tumor growth and prolonging relapse.

These findings made sense to researchers. Metformin treats metabolic problems in diabetes, and cancer has also been linked to metabolic issues such as obesity. Even before the 2005 British Medical Journal study, Goodwin had noticed that breast cancer patients with high insulin did worse than those with normal insulin levels.

That logic, plus the promising data, led scientists to conduct a number of randomized controlled trials—the gold-standard experiment in medicine. Researchers would enroll people with cancer and split them into two groups. One group would get standard cancer therapy plus metformin; the other group would get standard therapy plus a placebo, a pill containing no medication.

And metformin flopped, big time. While a number of studies are ongoing, trials for two types of cancer recently reported no benefit overall from metformin. In June 2024, at the American Society of Clinical Oncology meeting in Chicago, researchers reported a Canadian trial with 407 men with low-risk prostate cancer. The enrollees had been diagnosed within six months before starting the trial and had decided to monitor their cancer without starting immediate treatment. Half took metformin and half took a placebo. After biopsies at 18 and 36 months to test whether their disease had progressed, there was no difference between the two groups.

A larger British and Swiss trial including nearly 1,900 patients with newly diagnosed or relapsed prostate cancer that had spread to other body parts was reported at the European Society for Medical Oncology Congress in Barcelona, Spain, in September. This trial also found that metformin plus standard treatment, compared to standard treatment alone, did not improve overall prostate cancer survival in the study population.

A multinational study of breast cancer helmed by Goodwin also led to disappointment. The researchers enrolled more than 3,600 patients between 2010 and 2013; these patients had been diagnosed about a year before enrollment and had already undergone chemotherapy and surgery. In addition to standard cancer treatment, half received metformin and half received a placebo.

By 2016, it was clear that metformin wasn’t doing anything to enhance survival for about 1,100 participants with a particular cancer subtype. When the study wrapped in 2020, the researchers analyzed the rest of the patients, counting how many were alive and free of breast or any other form of cancer. Metformin made no difference in those results, or to survival overall, the team reported in 2022.

Fatal flaws in the research

In retrospect, researchers think they know why earlier studies oversold metformin’s potential. Many of the studies that examined medical records had a crucial flaw, says Samy Suissa, a pharmacoepidemiologist at McGill.

Here’s what happens: Researchers sift through old medical records to see if someone ever took metformin. Then they compare cancer rates among people who took the drug at any point to those who never took it. But you have to be alive to take metformin. Anyone who died, of cancer or other causes, before having a chance at a metformin prescription is left out of the calculations. This skews the results; it’s called the “immortal time bias.” It makes any drug, metformin or otherwise, look like it helps patients to survive because it can only be taken by people who are alive, says Suissa.

Plus, scientists are more likely to publish studies that show metformin is promising than ones where it makes no difference, skewing the scientific literature.

As for those studies of cells in dishes and of lab animals, many experiments used much higher doses of metformin than are used in people. Too much metformin risks a buildup of lactate, a byproduct of low oxygen metabolism that acidifies the blood and can be fatal.

Researchers still suspect metformin might treat specific subgroups of cancer. For example, the authors of the prostate cancer trial presented in Barcelona suggested that metformin might help patients whose cancer has spread to other tissues or multiple sites in their bones. And Goodwin saw a hint in her trial that it might help women whose cancers contain a certain version of a cell-growth gene called ERBB2. But it would require another trial, focused on women with that particular cancer, to prove it.

And there are now better treatments for those patients than there were more than a decade ago when Goodwin started her study, reducing the opportunity to test metformin. Goodwin doesn’t currently have the funding to follow up on this theory.

It may also be that the clinical trials recruited patients with cancers that were too far along. “I always thought we were asking too much of metformin,” says Victoria Bae-Jump, a gynecological oncologist at the University of North Carolina Lineberger Comprehensive Cancer Center in Chapel Hill. “Maybe it just needs to be earlier in the pathway of growth.” Bae-Jump is now testing metformin in women who have early-stage endometrial cancer or a precursor to it.

Others are investigating metformin for people who have precancerous lesions in their mouths. “The idea would be to keep them from progressing, or reverse the tissues to be more normal,” says Frank Ondrey, a head and neck cancer surgeon at the Masonic Cancer Center of the University of Minnesota in Minneapolis. In a small, uncontrolled study of 23 people, metformin halved lesion size in four of them. Ondrey is involved in two ongoing studies, one a randomized, controlled trial, to further test metformin in people with precancerous lesions; these should yield results within a few years.

Subdued expectations

Metformin is also being tested for other conditions such as dementia and a genetic disorder called fragile X syndrome. And perhaps the ultimate potential use for metformin is to slow aging itself. “I think it’s much easier to treat aging and prevent cancer than to treat cancer,” says Nir Barzilai, a geroscientist at Albert Einstein College of Medicine in New York and president of the nonprofit Academy for Health & Lifespan Research. Through its enhancement of insulin action and metabolism plus its minimization of free radical production, metformin influences all the key hallmarks of aging, such as problems with DNA, mitochondria and stem cells, says Barzilai.

He and colleagues are gathering funds for a randomized, controlled trial of metformin in 3,000 people age 65 through 79 who are showing signs of age-related disease already. The trial will test whether fewer people taking metformin die over six years. Barzilai, who is 68, says he is confident in metformin’s anti-aging ability and already takes the drug himself.

Others, mindful of what happened with cancer, are more circumspect. Pollak says that many of the studies in other areas of medicine are too small to prove metformin works, and Suissa notes that some of the studies finding benefits in populations taking metformin, including for longevity, have the same problems the oh-so-promising early cancer research did.

In short, Suissa says, “Don’t believe everything you hear.”

This story originally appeared in Knowable Magazine.

Knowable Magazine explores the real-world significance of scholarly work through a journalistic lens.

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Rare bear meat at gathering gives 10 people a scare—and parasitic worms

bear, CDC, health, infectious diseases, Meat, outbreak, parasite, Science, trichinella, trichinellosis / Rejus Almole / October 12, 2024

If you’re going to eat a bear, make sure it’s not rare.

You’d be forgiven for thinking that once the beast has been subdued, all danger has passed. But you might still be in for a scare. The animal’s flesh can be riddled with encased worm larvae, which, upon being eaten, will gladly reproduce in your innards and let their offspring roam the rest of your person, including invading your brain and heart. To defeat these savage squirmers, all one must do is cook the meat to at least 165° Fahrenheit.

But that simple solution continues to be ignored, according to a report today in the Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report. In this week’s issue, health officials in North Carolina report that rare bear meat was served at a November 23 gathering, where at least 22 people ate the meat and at least 10 developed symptoms of a worm infection. Of the 10, six were kids and teens between the ages of 10 and 18.

The infection is from the roundworm Trichinella, which causes trichinellosis. While the infection is rarely fatal, the nematodes tend to burrow out of the bowels and meander through the body, embedding in whatever muscle tissue they come across. A telltale sign of an infection in people is facial swelling, caused when the larvae take harbor in the muscles of the face and around the eyes. Of the 10 ill people in North Carolina, nine had facial swelling.

Local health officials were onto the outbreak when one person developed flu-like symptoms and puzzling facial swelling. They then traced it back to the gathering. The report doesn’t specify what kind of gathering it was but noted that 34 attendees in total were surveyed, from which they found the 22 people who ate the rare meat. The 10 people found with symptoms are technically considered only “probable” cases because the infections were never diagnostically confirmed. To confirm a trichinellosis infection, researchers need blood samples taken after the person recovers to look for antibodies against the parasite. None of the 10 people returned for blood draws.

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