Death is inevitable, says Michael Shermer. So why sweat it? Over 100 billion people have died before us, so maybe our fear of death is making our lives worse.
With its 2½-inch wing span, the Wallace’s giant bee is known as the largest bee on earth. But for decades, experts had feared it had gone extinct.
You can amplify light by bouncing it between the horizons of a black hole and a white hole. Now physicists have worked out how to build such a device in the lab.
Researchers have designed a tile set of DNA molecules that can carry out robust reprogrammable computations to execute six-bit algorithms and perform a variety of simple tasks. The system, which works thanks to the self-assembly of DNA strands designed to fit together in different ways while executing the algorithm, is an important milestone in constructing a universal DNA-based computing device.
The new system makes use of DNA’s ability to be programmed through the arrangement of its molecules. Each strand of DNA consists of a backbone and four types of molecules known as nucleotide bases – adenine, thymine, cytosine, and guanine (A, T, C, and G) – that can be arranged in any order. This order represents information that can be used by biological cells or, as in this case, by artificially engineered DNA molecules. The A, T, C, and G have a natural tendency to pair up with their counterparts: A base pairs with T, and C pairs with G. And a sequence of bases pairs up with a complementary sequence: ATTAGCA pairs up with TGCTAAT (in the reverse orientation), for example.
The DNA tile.
Successful manipulation of optogenomic interfaces can change our entire medical approach to many common neurological abnormalities, as well as better our interactions with machines.
A time cloak conceals events rather than objects. Cloaked messages were so secret no one could read them – now they can sneak along optical fibres before being revealed.
A team of chemists built the first artificial assembler, which uses light as the energy source. These molecular machines are performing synthesis in a similar way as biological nanomachines. Advantages are fewer side products, enantioselectivity, and shorter synthetic pathways since the mechanosynthesis forces the molecules into a predefined reaction channel.
Chemists usually synthesize molecules using stochastic bond-forming collisions of the reactant molecules in solution. Nature follows a different strategy in biochemical synthesis. The majority of biochemical reactions are driven by machine-type protein complexes that bind and position the reactive molecules for selective transformations. Artificial “molecular assemblers” performing “mechanosynthesis” have been proposed as a new paradigm in chemistry and nanofabrication. A team of chemists at Kiel University (Germany) built the first artificial assembler, that performs synthesis and uses light as the energy source. The system combines selective binding of the reactants, accurate positioning, and active release of the product. The scientists published their findings in the journal Communications Chemistry.
The idea of molecular assemblers, that are able to build molecules, has already been proposed in 1986 by K. Eric Drexler, based on ideas of Richard Feynman, Nobel Laureate in Physics. In his book “Engines of Creation: The Coming Era of Nanotechnology” and follow-up publications Drexler proposes molecular machines capable of positioning reactive molecules with atomic precision and to build larger, more sophisticated structures via mechanosynthesis. If such a molecular nanobot could build any molecule, it could certainly build another copy of itself, i.e. it could self-replicate. These imaginative visions inspired a number of science fiction authors, but also started an intensive scientific controversy.
Arizona State University has been selected to participate in DARPA’s Epigenetic CHaracterization and Observation (ECHO) program. According to DARPA, the “ECHO program has two primary challenges: to identify and discriminate epigenetic signatures created by exposure to threat agents; and to create technology that performs highly specific forensic and diagnostic analyses to reveal the exact type and time of exposure.” (Epigenetic changes are chemical modifications that affect genes, altering their expression while leaving the genetic code intact. Epigenetic changes can occur as natural responses to the environment but can also signal exposure to toxic agents or disease pathogens.)
Epigenetics is coming into its own in the 21st century. DARPA describes the epigenome as “biology’s record keeper,” explaining that “though DNA does not change over a single lifetime, a person’s environment may leave marks on the DNA that modify how that individual’s genes are expressed. This is one way that people can adapt and survive in changing conditions, and the epigenome is the combination of all of these modifications. Though modifications can register within seconds to minutes, they imprint the epigenome for decades, leaving a time-stamped biography of an individual’s exposures that is difficult to deliberately alter.”
Sethuraman Panchanathan, ASU Knowledge Enterprise executive vice president and chief research and innovation officer, said the project fits with the university’s mission.
Researchers have discovered a new drug that targets the mTOR pathway, which is involved in aging and metabolism. It could function as a caloric restriction mimetic, bringing about similar health benefits.
The mTOR pathway
The mechanistic target of rapamycin (mTOR) pathway is a part of metabolism and is one of the four major pathways that control it; collectively, the four pathways are affected by deregulated nutrient sensing, which is a hallmark of aging.
