76446369
submission
carmendrahl writes:
Tomes upon tomes have been written about the history of Germany's nuclear program in the 1940s (see Heisenberg's War, or The Making of the Atomic Bomb). Now, an international team has conducted nuclear forensic analysis of three WWII-era uranium samples from Germany. The results strongly suggest that in their wartime experiments, Germany's researchers never achieved a self-sustained nuclear chain reaction-- the chemical underpinning of atomic weaponry. The study appears in the journal Angewandte Chemie . Led by Maria Wallenius of the European Commission's in-house science service, researchers examined samples of uranium from two "Heisenberg cubes"- named for Werner Heisenberg, and a "Wirtz plate"-- named for Karl Wirtz. The team measured ratios of isotopes of the elements uranium, strontium, plutonium, and thorium. They also measured abundances of certain rare earth elements. They verified the samples as authentic, dating them to the early 1940s, and localizing the area where the uranium ore was mined to the Czech Republic (which was under Nazi control at the time). They also demonstrated that the isotopes of uranium-236 and plutonium-239 occur in levels matching what would be expected naturally. ”This suggests that the uranium samples have not been exposed to a significant neutron fluence," Wallenius said in a statement.
60361853
submission
carmendrahl writes:
Lethal injections are typically regarded as far more humane methods for execution compared to predecessors such as hanging and firing squads.
But the truth about the procedure's humane-ness is unclear. Major medical associations have declared involvement of their member physicians in executions to be unethical, so that means that relatively inexperienced people administer the injections. Mounting supply challenges for the lethal drug cocktails involved are forcing execution teams to change procedures on the fly. This and other problems have contributed to recent crises in Oklahoma and Missouri.
As a new story and interactive graphic explains, states are turning to a number of compound cocktails to get around the supply problems.
55362137
submission
carmendrahl writes:
Last fall, MIT researchers made news for developing two bioinspired cocktail toppers-- a moving cocktail boat and a floral pipette-- in collaboration with James Beard Award-winning chef José Andrés. Both the boat and floral pipette operate by taking advantage of surface tension-- either to propel the boat forward or to keep small drops of liquid inside the flower's petals. Some of those early garnishes were nominally edible. But to make them worthy of a restaurant debut requires balancing of flavors, temperature, density, and alcohol content, among other factors. A story and video go inside Andrés' company ThinkFoodGroup to see how the project is coming along. The toppers aren't available to the public just yet.
53421413
submission
carmendrahl writes:
Exposure to certain pesticides, including rotenone and paraquat, has been associated with a higher incidence of Parkinson's disease in population studies. But how did scientists come to think of a link between Parkinson's disease and pesticides in the first place? The answer involves the 1980s drug underworld, where criminals were synthesizing modified versions of illegal drugs such as heroin to stay one step ahead of the law. One molecule in some designer heroin cocktails, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), breaks down in the human body into 1-methyl-4-phenylpyridinium (MPP+), a nerve cell killer. Heroin addicts exposed to this molecule got Parkinson's-like symptoms. As for the connection to pesticides, MPP+ is a weed killer that was used in the 70s. It also closely resembles the structure of the pesticide paraquat. The saga, therefore, put scientists on high alert to the possibility that pesticides might play a role in developing Parkinson's.
51098743
submission
carmendrahl writes:
Eukaryotic cells, which are defined by having a nucleus, rarely grow larger than 10 m in diameter. Scientists know a few reasons why this is so. A new study suggests another reason--gravity. Studying egg cells from the frog Xenopus laevis, which reach as big as 1 mm across and are common research tools, Princeton researchers Marina Feric and Clifford Brangwynne noticed that the insides of the eggs' nuclei settled to the bottom when they disabled a mesh made from the cytoskeleton protein actin. They think the frog eggs evolved the mesh to counteract gravity, which according to their calculations becomes significant if cells get bigger than 10 m in diameter.
49946317
submission
carmendrahl writes:
Famed astronomer Galileo Galilei is best known for taking on the Catholic Church by championing the idea that the Earth moves around the sun. But he also engaged in a debate with a philosopher about why ice floats on water. While his primary arguments were correct, he went too far, belittling legitimate, contradictory evidence given by his opponent, Ludovico delle Colombe. Galileo's erroneous arguments during the water debate are a useful reminder that the path to scientific enlightenment is not often direct and that even our intellectual heroes can sometimes be wrong.
49454903
submission
carmendrahl writes:
The abundance of shale gas in the U.S. is expected to lower the cost of petrochemicals for fuel and other applications. That's making it harder for plant-based, renewable feedstocks to compete in terms of price. In the search for cost-competitive crops, companies are testing plants other than traditional biofuel sources such as corn and sugarcane. In a video, watch how the firm Canergy is test-growing a relative of sugarcane called energy cane, which is expected to yield 5 times the ethanol per acre compared to corn.
44952787
submission
carmendrahl writes:
3-D printers don’t build only solid objects anymore. They also build liquid objects, thanks to a research team at the University of Oxford. The group custom crafted a 3D printer to squirt tiny liquid droplets from its nozzles. The 3-D patterned droplets can mimic biological tissues, such as nerve fibers, and may have potential in tissue engineering applications. An expert not involved with the study is cautious about endorsing the tissue engineering applications because they're not yet demonstrated, but praises the team for extending 3-D printing to new classes of materials.
