Physics Today Daily Edition
Science: A clinical test will begin this month in which ultrasound will be used to deliver chemotherapy drugs to treat brain cancer. Ultrasound will briefly open the blood–brain barrier, which normally prevents drugs from reaching the brain. The risk is that ultrasound has the potential to directly damage brain tissue, so testing the technique on humans may not be as successful as earlier tests performed on rodents. Separately, Sunnybrook Research Institute's Kullervo Hynynen, who first tested ultrasound's effect on the blood–brain barrier, and his colleagues have used the technique on the brains of mice and found it eliminated abnormal clumps similar to those present in patients with Alzheimer's disease. They reported that the cognitive ability of the treated mice was restored.
New York Times: A fleet of four identical spacecraft is set to be launched from Cape Canaveral, Florida, this evening aboard an Atlas 5 rocket. The satellites will assume a tetragonal formation in orbit above Earth as part of NASA's two-year, $1.1 billion Magnetospheric Multiscale mission to study the planet's protective magnetic field. That field protects Earth from the radiation of the Sun's solar wind. However, how the field reacts when struck by solar flares is poorly understood. The arrangement of the satellites will allow researchers to image the magnetic field in three dimensions.
BBC: The Anthropocene is a proposed geological era to mark the point at which humans first had a significant global effect. Officially, we are still in the Holocene, which began at the end of the last glaciation, roughly 11 500 years ago. Different moments in the past several hundred years have been put forward as the beginning of the new human-dominated era. Mark Maslin of University College London and his colleagues have now proposed that 1610 CE should be the start point for the Anthropocene because of changes in global sediments and ice. Maslin and his group say the changes were triggered after the discovery of the Americas by European explorers. As a result of European expansion, several crops moved between continents and introduced new pollens into sediments around the world. Additionally, diseases brought to the Americas killed a significant percentage of the population, which resulted in a large reduction in the amount of land being farmed and thus a huge drop in atmospheric carbon. The researchers' proposal is a counter to a popular alternative that uses the introduction and proliferation of nuclear weapons as the demarkation point. Later this year an international working group is expected to choose an official date for the beginning of the Anthropocene.
Nature: Michael Levin of Tufts University in Medford, Massachusetts, and his colleagues have investigated the way bioelectric signals in animal cells can be altered during embryonic growth to trigger unusual results, such as the development of a functional eye in a tadpole's tail and additional legs on frogs. Now they have shown that changing voltage gradients across cell membranes in the brains of frog embryos can stimulate the growth of additional brain cells. Their approach is based on the fact that cells communicate with each other through voltage gradients. By adjusting communication between certain areas, Levin's team was able to stimulate unusual growth. In the case of the brain cell study, the stimulated growth was even enough to overcome genetic mutations that normally resulted in brain defects.
Wired: A team of researchers from the University of Cambridge has discovered nine objects that appear to be dwarf galaxies in orbit around the Milky Way. It is the first such discovery since 2006. The objects were uncovered in data collected as part of an investigation into dark energy by the 570-megapixel Dark Energy Camera, which is mounted on the Victor M. Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory in the Chilean Andes. The researchers have confirmed that three of the objects are dwarf galaxies; the other six could be either dwarf galaxies or star clusters with similar properties. The objects are located in the same area as both the Large and Small Magellanic Clouds, with the closest being about 97 000 light-years away and the farthest 1.2 million light-years. Because dwarf galaxies are 99% dark matter, they present an excellent opportunity to study the mysterious substance.
MIT Technology Review: The Joint Center for Artificial Photosynthesis (JCAP) was established by the Department of Energy in 2010 as one of the agency's Innovation Hubs. Now the center's researchers have demonstrated a device that uses solar energy to electrolyze water. Electrolysis produces hydrogen gas, which can be stored and used to generate electricity. With conventional electrolysis, it costs between $10 and $20 to produce the amount of hydrogen fuel equivalent to one gallon of gasoline. Solar electrolysis could reduce that cost to $2–4, according to JCAP director Nathan Lewis. The system that JCAP developed combines electrolysis catalysts with solar cells to produce a less complex system of electrodes that have a lifetime of 1000 hours. Although that is not long enough for commercial devices, it shows significant progress. However, the $122 million originally provided to JCAP will run out later this year unless Congress provides more funding.
Miami Herald: In 2011, Governor Rick Scott took office in Florida and appointed Herschel Vinyard Jr as the director of the state’s Department of Environmental Protection (DEP). According to many DEP employees, shortly thereafter they were instructed to stop using phrases such as “climate change” and “global warming” in official documents and statements. However, both Tiffany Cowie, the DEP’s press secretary, and Jeri Bustamante, Scott’s spokeswoman, have denied that any such policy was ever put in place. Scott has previously said that he was not convinced by the evidence for climate change and also that he is “not a scientist.” Florida is under severe threat from the effects of climate change; up to 30% of its beaches are predicted to be submerged by the end of the century as sea levels rise.