Marijuana’s medical promise deserves closer, better-funded scientific scrutiny, a new state-of-the-science report concludes.
The report, released January 12 by the National Academies of Sciences, Engineering and Medicine in Washington, D.C., calls for expanding research on potential medical applications of cannabis and its products, including marijuana and chemical components called cannabinoids.
Big gaps in knowledge remain about health effects of cannabis use, for good or ill. Efforts to study these effects are hampered by federal classification of cannabis as a Schedule 1 drug, meaning it has no accepted medical use and a high potential for abuse. Schedule 1 status makes it difficult for researchers to access cannabis. The new report recommends reclassifying the substance to make it easier to study. Recommendations from the 16-member committee that authored the report come at a time of heightened acceptance of marijuana and related substances. Cannabis is a legal medical treatment in 28 states and the District of Columbia. Recreational pot use is legal in eight of those states and the District.
“The legalization and commercialization of cannabis has allowed marketing to get ahead of science,” says Raul Gonzalez, a psychologist at Florida International University in Miami who reviewed the report before publication. While the report highlights possible medical benefits, Gonzalez notes that it also underscores negative consequences of regular cannabis use. These include certain respiratory and psychological problems.
A 2015 survey indicated that around 22 million people in the United States ages 12 and older ingested some form of cannabis in the last month, mainly as a recreational drug. Roughly 10 percent of those people reported using cannabis solely for medical reasons and 36 percent reported a mix of recreational and medical use.
“This growing acceptance, accessibility and use of cannabis and its derivatives have raised important public health concerns,” says committee chair Marie McCormick, a Harvard T.H. Chan School of Public Health pediatrician.
She and her committee colleagues considered more than 10,700 abstracts of studies on cannabis’s health effects published between January 1, 1999, and August 1, 2016. The committee gave special weight to research reviews published since 2011. Cannabis and cannabinoids show medical potential, the report concludes. Evidence indicates that these substances substantially reduce chronic pain in adults. Cannabis derivatives ingested in pills by multiple sclerosis patients temporarily reduce self-reported muscle spasms (SN: 6/19/10, p. 16). Cannabinoids also help to prevent and lessen chemotherapy-induced nausea and vomiting in adults.
Less conclusive evidence suggests cannabis and cannabinoids improve sleep for adults with sleep apnea, fibromyalgia, chronic pain and multiple sclerosis, the report says.
“If cannabis was to be classified as a medicine, then it needs to be rigorously tested like all other medicines,” says pharmacologist Karen Wright of Lancaster University in England. She hopes the new report spurs researchers to develop standards for the chemical composition of cannabis products tested as possible medical treatments. Despite cannabis’s medical promise, scientists have more questions than answers about how its use influences physical and mental health.
Encouragingly, studies reviewed by the committee suggest that smoking marijuana, unlike smoking cigarettes, does not increase the chances of developing lung, head and neck cancers. But pot’s relationship to other cancers — as well as to heart attacks, strokes and diabetes — is unclear. And few or no findings support the use of cannabis to treat Tourette’s syndrome, post-traumatic stress disorder, cancer, epilepsy (SN Online: 4/13/15) or other medical ailments.
Evidence does not conclusively link marijuana smoking to respiratory diseases such as asthma. But regular pot use tends to accompany increased chronic bronchitis episodes and an intensified cough and phlegm production, at least until smoking stops.
Cannabis smoke may deter infection-related inflammation in the body. But data are sparse on whether cannabis or its derivatives influence immune responses in healthy people or those with HIV.
There are some clear downsides to consuming marijuana and related substances, the new report adds. Solid scientific support exists for a link between cannabis use and later development of psychotic disorders such as schizophrenia. A moderate relationship exists between cannabis use and the development of addictions to alcohol, tobacco and illegal drugs.
Fairly strong evidence points to learning, memory and attention problems immediately after smoking marijuana. Limited data, however, tie pot use to academic problems, dropping out of school, unemployment or lowered income in adulthood.
Platinum, one of the rarest and most expensive metals on Earth, may soon find itself out of a job. Known for its allure in engagement rings, platinum is also treasured for its ability to jump-start chemical reactions. It’s an excellent catalyst, able to turn standoffish molecules into fast friends. But Earth’s supply of the metal is limited, so scientists are trying to coax materials that aren’t platinum — aren’t even metals — into acting like they are.
For years, platinum has been offering behind-the-scenes hustle in catalytic converters, which remove harmful pollutants from auto exhaust. It’s also one of a handful of rare metals that move along chemical reactions in many well-established industries. And now, clean energy technology opens a new and growing market for the metal. Energy-converting devices like fuel cells being developed to power some types of electric vehicles rely on platinum’s catalytic properties to transform hydrogen into electricity. Even generating the hydrogen fuel itself depends on platinum.
Without a cheaper substitute for platinum, these clean energy technologies won’t be able to compete against fossil fuels, says Liming Dai, a materials scientist at Case Western Reserve University in Cleveland.
To reduce the pressure on platinum, Dai and others are engineering new materials that have the same catalytic powers as platinum and other metals — without the high price tag. Some researchers are replacing expensive metals with cheaper, more abundant building blocks, like carbon. Others are turning to biology, using catalysts perfected by years of evolution as inspiration. And when platinum really is best for a job, researchers are retooling how it is used to get more bang for the buck. Moving right along Catalysts are the unsung heroes of the chemical reactions that make human society tick. These molecular matchmakers are used in manufacturing plastics and pharmaceuticals, petroleum and coal processing and now clean energy technology. Catalysts are even inside our bodies, in the form of enzymes that break food into nutrients and help cells make energy. During any chemical reaction, molecules break chemical bonds between their atomic building blocks and then make new bonds with different atoms — like swapping partners at a square dance. Sometimes, those partnerships are easy to break: A molecule has certain properties that let it lure away atoms from another molecule. But in stable partnerships, the molecules are content as they are. Left together for a very long period of time, a few might eventually switch partners. But there’s no mass frenzy of bond breaking and rebuilding.
Catalysts make this breaking and rebuilding happen more efficiently by lowering the activation energy — the threshold amount of energy needed to make a chemical reaction go. Starting and ending products stay the same; the catalyst just changes the path, building a paved highway to bypass a bumpy dirt road. With an easier route, molecules that might take years to react can do so in seconds instead. A catalyst doesn’t get used up in the reaction, though. Like a wingman, it incentivizes other molecules to react, and then it bows out.
A hydrogen fuel cell, for example, works by reacting hydrogen gas (H2) with oxygen gas (O2) to make water (H2O) and electricity. The fuel cell needs to break apart the atoms of the hydrogen and oxygen molecules and reshuffle them into new molecules. Without some assistance, the reshuffling happens very slowly. Platinum propels those reactions along. Platinum works well in fuel cell reactions because it interacts just the right amount with both hydrogen and oxygen. That is, the platinum surface attracts the gas molecules, pulling them close together to speed along the reaction. But then it lets its handiwork float free. Chemists call that “turnover” — how efficiently a catalyst can draw in molecules, help them react, then send them back out into the world.
Platinum isn’t the only superstar catalyst. Other metals with similar chemical properties also get the job done — palladium, ruthenium and iridium, for example. But those elements are also expensive and hard to get. They are so good at what they do that it’s hard to find a substitute. But promising new options are in the works. Carbon is key Carbon is a particularly attractive alternative to precious metals like platinum because it’s cheap, abundant and can be assembled into many different structures.
Carbon atoms can arrange themselves into flat sheets of orderly hexagonal rings, like chicken wire. Rolling these chicken wire sheets — known as graphene — into hollow tubes makes carbon nanotubes, which are stronger than steel for their weight. But carbon-only structures don’t make great catalysts.
“Really pure graphene isn’t catalytically active,” says Huixin He, a chemist at Rutgers University in Newark, N.J. But replacing some of the carbon atoms in the framework with nitrogen, phosphorus or other atoms changes the way electric charge is distributed throughout the material. And that can make carbon behave more like a metal. For example, nitrogen atoms sprinkled like chocolate chips into the carbon structure draw negatively charged electrons away from the carbon atoms. The carbon atoms are left with a more positive charge, making them more attractive to the reaction that needs a nudge.
That movement of electrical charge is a prerequisite for a material to act as a catalyst, says Dai, who has pioneered the development of carbon-based, metal-free catalysts. His lab group demonstrated in 2009 in Science that clumps of nitrogen-containing carbon nanotubes aligned vertically — like a fistful of uncooked spaghetti — could stand in for platinum to help break apart oxygen inside fuel cells. To perfect the technology, which he has patented, Dai has been swapping in different atoms in different combinations and experimenting with various carbon structures. Should the catalyst be a flat sheet of graphene or a forest of rolled up nanotubes, or some hybrid of both? Should it contain just nitrogen and carbon, or a smorgasbord of other elements, too? The answer depends on the specific application.
In 2015 in Science Advances, Dai demonstrated that nitrogen-studded nanotubes worked in acid-containing fuel cells, one of the most promising designs for electric vehicles.
Other researchers are playing their own riffs on the carbon concept. To produce graphene’s orderly structure requires just the right temperature and specific reaction conditions. Amorphous carbon materials — in which the atoms are randomly clumped together — can be easier to make, Rutgers’ He says.
In one experiment, He’s team started with liquid phytic acid, a substance made of carbon, oxygen and phosphorus. Microwaving the liquid for less than a minute transformed it into a sooty black powder that she describes as a sticky sort of sand.
“Phytic acid strongly absorbs microwave energy and changes it to heat so fast,” she says. The heat rearranges the atoms into a jumbled carbon structure studded with phosphorus atoms. Like the nitrogen atoms in Dai’s nanotubes, the phosphorus atoms changed the movement of electric charge through the material and made it catalytically active, He and colleagues reported last year in ACS Nano.
The sooty phytic acid–based catalyst could help move along a different form of clean energy: It sped up a reaction that turns a big, hard-to-use molecule found in cellulose — a tough, woody component of plants — into something that can react with other molecules. That product could then be used to make fuel or other chemicals. He is still tweaking the catalyst to make it work better.
He’s catalyst particles get mixed into the chemical reaction (and later need to be strained out). These more jumbled carbon structures with nitrogen or phosphorus sprinkled in can work in fuel cells, too — and, she says, they’re easier to make than graphene.
Enzyme-inspired energy Rather than design new materials from the bottom up, some scientists are repurposing catalysts already used in nature: enzymes. Inside living things, enzymes are involved in everything from copying genetic material to breaking down food and nutrients.
Enzymes have a few advantages as catalysts, says M.G. Finn, a chemist at Georgia Tech. They tend to be very specific for a particular reaction, so they won’t waste much energy propelling undesired side reactions. And because they can evolve, enzymes can be tailored to meet different needs.
On their own, enzymes can be too fragile to use in industrial manufacturing, says Trevor Douglas, a chemist at Indiana University in Bloomington. For a solution, his team looked to viruses, which already package enzymes and other proteins inside protective cases.
“We can use these compartments to stabilize the enzymes, to protect them from things that might chew them up in the environment,” Douglas says. The researchers are engineering bacteria to churn out virus-inspired capsules that can be used as catalysts in a variety of applications. His team mostly uses enzymes called hydrogenases, but other enzymes can work, too. The researchers put the genetic instructions for making the enzymes and for building a protective coating into Escherichia coli bacteria. The bacteria go into production mode, pumping out particles with the hydrogenase enzymes protected inside, Douglas and colleagues reported last year in Nature Chemistry. The protective coating keeps chunky enzymes contained, but lets the molecules they assist get in and out.
“What we’ve done is co-opt the biological processes,” Douglas says. “All we have to do is grow the bacteria and turn on these genes.” Bacteria, he points out, tend to grow quite easily. It’s a sustainable system, and one that’s easily tailored to different reactions by swapping out one enzyme for another.
The enzyme-containing particles can speed along generation of the hydrogen fuel, he has found. But there are still technical challenges: These catalysts last only a couple of days, and figuring out how to replace them inside a consumer device is hard.
Other scientists are using existing enzymes as templates for catalysts of their own design. The same family of hydrogenase enzymes that Douglas is packaging into capsules can be a launching point for lab-built catalysts that are even more efficient than their natural counterparts.
One of these hydrogenases has an iron core plus an amine — a nitrogen-containing string of atoms — hanging off. Just as the nitrogen worked into Dai’s carbon nanotubes affected the way electrons were distributed throughout the material, the amine changes the way the rest of the molecule acts as a catalyst.
Morris Bullock, a researcher at Pacific Northwest National Laboratory in Richland, Wash., is trying to figure out exactly how that interaction plays out. He and colleagues are building catalysts with cheap and abundant metals like iron and nickel at their core, paired with different types of amines. By systematically varying the metal core and the structure and position of the amine, they’re testing which combinations work best.
These amine-containing catalysts aren’t ready for prime time yet — Bullock’s team is focused on understanding how the catalysts work rather than on perfecting them for industry. But the findings provide a springboard for other scientists to push these catalysts toward commercialization.
Sticking with the metals These new types of catalysts are promising — many of them can speed up reactions almost as well as a traditional platinum catalyst. But even researchers working on platinum alternatives agree that making sustainable and low-cost catalysts isn’t always as simple as removing the expensive and rare metals.
“The calculation of sustainability is not completely straightforward,” Finn says. Though he works with enzymes in his lab, he says, “a platinum-based catalyst that lasts for years is probably going to be more sustainable than an enzyme that degrades.” It might end up being cheaper in the long run, too. That’s why researchers working on these alternative catalysts are pushing to make their products more stable and longer-lasting. “If you think about a catalyst, it’s really the atoms on the surface that participate in the reaction. Those in the bulk may just provide mechanical support or are just wasted,” says Younan Xia, a chemist at Georgia Tech. Xia is working on minimizing that waste.
One promising approach is to shape platinum into what Xia dubs “nanocages” — instead of a solid cube of metal, just the edges remain, like a frame.
It’s also why many scientists haven’t given up on metal. “I don’t think you can say, ‘Let’s do without metals,’ ” says James Clark, a chemist at the University of York in England. “Certain metals have a certain functionality that’s going to be very hard to replace.” But, he adds, there are ways to use metals more efficiently, such as using nanoparticle-sized pieces that have a higher surface area than a flat sheet, or strategically combining small amounts of a rare metal with cheaper, more abundant nickel or iron. Changing the structure of the material on a nanoscale level also can make a difference.
In one experiment, Xia started with cubes of a different rare metal, palladium. He coated the palladium cubes with a thin layer of platinum just a few atoms thick — a pretty straightforward process. Then, a chemical etched away the palladium inside, leaving a hollow platinum skeleton. Because the palladium is removed from the final product, it can be used again and again. And the nanocage structure leaves less unused metal buried inside than a large flat sheet or a solid cube, Xia reported in 2015 in Science.
Since then, Xia’s team has been developing more complex shapes for the nanocages. An icosahedron, a ball with 20 triangular faces, worked especially well. The slight disorder to the structure — the atoms don’t crystallize quite perfectly — helped make it four times as active as a commercial platinum catalyst. He has made similar cages out of other rare metals like rhodium that could work as catalysts for other reactions.
It’ll take more work before any of these new catalysts fully dethrone platinum and other precious metals. But once they do, that’ll leave more precious metals to use in places where they can truly shine.
An expectant mom might want to think twice about quenching her thirst with soda.
The more sugary beverages a mom drank during mid-pregnancy, the heavier her kids were in elementary school compared with kids whose mothers consumed less of the drinks, a new study finds. At age 8, boys and girls weighed approximately 0.25 kilograms more — about half a pound — with each serving mom added per day while pregnant, researchers report online July 10 in Pediatrics. “What happens in early development really has a long-term impact,” says Meghan Azad, an epidemiologist at the University of Manitoba in Canada, who was not involved in the study. A fetus’s metabolism develops in response to the surrounding environment, including the maternal diet, she says.
The new findings come out of a larger project that studies the impact of pregnant moms’ diets on their kids’ health. “We know that what mothers eat during pregnancy may affect their children’s health and later obesity,” says biostatistician Sheryl Rifas-Shiman of Harvard Medical School and Harvard Pilgrim Health Care Institute in Boston. “We decided to look at sugar-sweetened beverages as one of these factors.” Sugary drinks are associated with excessive weight gain and obesity in studies of adults and children.
Rifas-Shiman and colleagues included 1,078 mother-child pairs in the study. Moms filled out a questionnaire in the first and second trimesters of their pregnancy about what they were drinking — soda, fruit drinks, 100 percent fruit juice, diet soda or water — and how often. Soda and fruit drinks were considered sugar-sweetened beverages. A serving was defined as a can, glass or bottle of a beverage.
When the children of these moms were in elementary school, the researchers assessed the kids using several different measurements of obesity. They took kids’ height and weight to calculate body mass index and performed a scanning technique to determine total fat mass, among other methods.
Of the 1,078 kids in the study, 272, or 25 percent, were considered overweight or obese based on their BMI. Moms who drank at least two servings of sugar-sweetened beverages per day during the second trimester had children most likely to fall in this group. Other measurements of obesity were also highest for these kids. Children’s own sugary beverage drinking habits did not alter the results, the scientists say.
The research can’t say moms’ soda sips directly caused the weight gain in her kids. But based on this study and other work, limiting sugary drinks during pregnancy “is probably a good idea,” Azad says. There’s no harm in avoiding them, “and it looks like there may be a benefit.” Her advice is to drink water instead.
Speculation is running rampant about potential new discoveries of gravitational waves, just as the latest search wound down August 25.
Publicly available logs from astronomical observatories indicate that several telescopes have been zeroing in on one particular region of the sky, potentially in response to a detection of ripples in spacetime by the Advanced Laser Interferometer Gravitational-Wave Observatory, LIGO. These records have raised hopes that, for the first time, scientists may have glimpsed electromagnetic radiation — light — produced in tandem with gravitational waves. That light would allow scientists to glean more information about the waves’ source. Several tweets from astronomers reporting rumors of a new LIGO detection have fanned the flames of anticipation and amplified hopes that the source may be a cosmic convulsion unlike any LIGO has seen before. “There is a lot of excitement,” says astrophysicist Rosalba Perna of Stony Brook University in New York, who is not involved with the LIGO collaboration. “We are all very anxious to actually see the announcement.”
An Aug. 25 post on the LIGO collaboration’s website announced the end of the current round of data taking, which began November 30, 2016. Virgo, a gravitational wave detector in Italy, had joined forces with LIGO’s two on August 1 (SN Online: 8/1/17). The three detectors will now undergo upgrades to improve their sensitivity. The update noted that “some promising gravitational-wave candidates have been identified in data from both LIGO and Virgo during our preliminary analysis, and we have shared what we currently know with astronomical observing partners.”
When LIGO detects gravitational waves, the collaboration alerts astronomers to the approximate location the waves seemed to originate from. The hope is that a telescope could pick up light from the aftermath of the cosmic catastrophe that created the gravitational waves — although no light has been found in previous detections.
LIGO previously detected three sets of gravitational waves from merging black holes (SN: 6/24/17, p. 6). Black hole coalescences aren’t expected to generate light that could be spotted by telescopes, but another prime candidate could: a smashup between two remnants of stars known as neutron stars. Scientists have been eagerly awaiting LIGO’s first detections of such mergers, which are suspected to be the sites where the universe’s heaviest elements are formed. An observation of a neutron star crash also could provide information about the ultradense material that makes up neutron stars. Since mid-August, seemingly in response to a LIGO alert, several telescopes have observed a section of sky around the galaxy NGC 4993, located 134 million light-years away in the constellation Hydra. The Hubble Space Telescope has made at least three sets of observations in that vicinity, including one on August 22 seeking “observations of the first electromagnetic counterparts to gravitational wave sources.”
Likewise, the Chandra X-ray Observatory targeted the same region of sky on August 19. And records from the Gemini Observatory’s telescope in Chile indicate several potentially related observations, including one referencing “an exceptional LIGO/Virgo event.”
“I think it’s very, very likely that LIGO has seen something,” says astrophysicist David Radice of Princeton University, who is not affiliated with LIGO. But, he says, he doesn’t know whether its source has been confirmed as merging neutron stars.
LIGO scientists haven’t commented directly on the veracity of the rumor. “We have some substantial work to do before we will be able to share with confidence any quantitative results. We are working as fast as we can,” LIGO spokesperson David Shoemaker of MIT wrote in an e-mail.
Former Raiders receiver Henry Ruggs III has been ordered to appear in Las Vegas court on Monday following a missed alcohol test. That is a violation of his bond release restrictions following a fatal crash in which prosecutors say he was driving under the influence at 156 mph.
According to Clarke County court records, Ruggs missed one of four daily court-mandated alcohol tests at 4:41 p.m. local time on Saturday before completing "a client initiated remote breath test" at 6:28 p.m. the same day. The alcohol monitoring agency noted in court filings that it couldn't verify Ruggs' sobriety at the time he was supposed to complete his test earlier in the day. Ruggs' attorney David Chesnoff told Judge Suzan Baucum — who has ordered his reappearance in court — that the delay in his test was related to trouble with equipment provided to him. Ruggs, 22, could face a return to jail for violating the terms of his release. Ruggs was released on $150,000 bond on Wednesday, Nov. 3 and was ordered to remain on house arrest while undergoing electronic surveillance. He is also to refrain from alcohol or other controlled substances, among other restrictions.
Ruggs was arrested after his involvement in a fatal drunk-driving accident on Tuesday, Nov. 2. Prosecutors said he was driving 156 mph at the time of the crash, with a blood alcohol content level of .16 — twice the legal limit for Nevada drivers. Ruggs' Chevrolet Corvette struck the back of 23-year-old Tina Tintor's Toyota Rav4. Witnesses to the event indicated they tried to help Tintor and her dog escape the vehicle, but were ultimately forced back from flames emanating from the car. Ruggs faces two felony charges of DUI resulting in death or serious injury. That is considered a category B felony in Nevada, the second-worst violation of state law. The charges are non-probationary, meaning Ruggs will face jail time if convicted. Each charge carries a minimum two-year sentence, but can go as long as 20 years. He also faces two counts of felony reckless driving — charges with penalties of one to six years in prison — and a misdemeanor weapon charge.
The Raiders released Ruggs on Nov. 2 following his DUI arrest. He was the No. 12 overall pick in the 2020 NFL Draft, and the highest receiver taken in the draft.
