SciTech #ScienceSunday Digest, 07/14.Click-linked DNA, internal cochlear device, nanocrystalline sheets, insect robots, red-blue optogenetics, LIDAR chips, restoring senescent cells, white matter map, fusion unity.1. Transcriptional Viability for Click-Linked DNA.
For the first time a synthetic DNA linker backbone has been demonstrated as functional in a living eukaryotic cell http://onlinelibrary.wiley.com/doi/10.1002/anie.201308691/full
. A new synthetic click-chemistry reaction process able to create arbitrary DNA sequences cheaper, quicker, and easier than standard enzymatic DNA assembly approaches actually replaces the natural backbone with a triazole molecule. This advances the goal of total chemical synthesis and assembly of genes and genomes. The functional nature of the DNA sequences produced was demonstrated by splicing into a eukaryotic cell, from which error-free transcribed mRNA was observed, as well as the fluorescent protein that the sequence encoded. Cellular machinery therefore tolerates the non-natural DNA, but I still wonder about transcriptional efficiency comparisons with natural DNA. Yet another big advance for fundamental biotechnology tools, making DNA synthesis cheaper and easier. 2. Fully Internal Cochlear Implants Now Possible.
Future cochlear implants will probably not need any visible external hardware at all. This is thanks to a new low power signal processing chip that can be wireless recharged and which uses the natural microphone of the middle ear http://web.mit.edu/newsoffice/2014/cochlear-implants-with-no-exterior-hardware-0209.html
. Originally developed to assist patients with middle-ear hearing loss in which the middle-ear bones do not vibrate strongly enough to activate the auditory nerve, the same design should provide low-power, fully-internal benefits to other hearing aid devices such as cochlear implants. 3. Self-Assembling Two-Dimensional Nanocrystalline Sheets.
New theoretical work shows how cadmium selenide (CdSe) semiconducting nanocrystals should self-assemble via facet-specific attachment into two-dimensional honeycomb lattice sheets http://prx.aps.org/pdf/PRX/v4/i1/e011010
, colloquially referred to by the popular press as “artificial graphene”. The excitement around the work stems from the wide-ranging possibilities that such a platform enables, with tantalising results indicating topological insulator, conductor, and semiconductor regions in the same system. All properties can be tailored by altering the materials and nanogeometry. All they need to do now is reduce to practice and create a real physical system. 4. Early Insect-Like Robots.
Researchers claim to have developed a robot that uses the nervous system of honeybees as a model to operate, mimicking the neural network that connects sensory input to motor output http://www.fu-berlin.de/en/presse/informationen/fup/2014/fup_14_040-roboter-insekten-fortbewegung/index.html
. This is the first time that robots have been conditioned in in a one-shot learning experiment via spiking neural networks. In related work self-organising robots inspired by termite colonies demonstrate swarm-like intelligence in building complex structures out of modular building blocks http://www.seas.harvard.edu/news/2014/02/robotic-construction-crew-needs-no-foreman
, and new algorithms enable herding collaborative fleets of robots http://web.mit.edu/newsoffice/2014/herding-robots-0212.html
. 5. Growing Sophistication for Optogenetic Tools.
Optogenetics, the practice of inserting genes for membrane-bound light-sensitive proteins into neurons so that they can be controlled with light has been given a boost with the discovery of a range of new opsin proteins that are sensitive to either red or blue light, and which allow complex control of two populations of neurons at once http://web.mit.edu/newsoffice/2014/optogenetic-toolkit-goes-multicolor-0209.html
. The discovery of these natural opsins was fortuitous given that various groups had tried to engineer modified opsins to achieve this ability but failed due to structural trade-offs. These new tools allow studies, investigations, and interventions into neuronal circuits that were not possible before. 6. Sequencing the DNA of IVF Embryos.
Preimplantation Genetic Diagnosis takes a big step forward with high-throughput DNA sequencing of embryos during in vitro
. This first trial will be concentrating on chromosomal abnormalities, which is the most common cause of IVF failure, but it will also be assessing the feasibility of using the method to screen for genetic diseases known to affect a family. This and other methods are expected to significantly improve the efficiency and cost of IVF procedures generally; I suspect it won’t be much longer before we see similar research using CRISPR and other methods to make genomic corrections for embryos. 7. Advanced 3D LIDAR Chip.
New single-photon infrared detectors power the most advanced LIDAR (light detection and ranging) 3D imaging system ever produced http://www.technologyreview.com/news/524166/the-worlds-most-powerful-3-d-laser-imager/
. The new chip plus optics allow high altitude aerial 3D mapping of land and building features to high resolution much quicker than prior systems, potentially creating in minutes 3D maps that used to take days of flight. Another promising application is for cars, such as self-driving cars, that make use of LIDAR systems as part of their environmental awareness and real-time navigation processes; quicker, cheaper, better sensors would be a boon here. 8. Senescent Cells - Harm & Reversal.
Old, defective, and non-productive senescent cells accumulate with age and contribute to a range of age-related diseases. One recent example of this is the demonstration that the accumulation of senescent cells directly leads to a decline in the ability of the kidney to repair damage and regenerate internal structures http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0088071
, something that youthful kidneys are able to do. There are many avenues being explored to reverse cellular senescence, and one recent example simply involved the silencing of one particular gene (p16INK4a) in senescent muscle stem cells, which resulted in the restoration of regenerative function in aged muscles https://www.fightaging.org/archives/2014/02/silencing-p16-to-reverse-senescence-in-old-muscle-stem-cells.php
. Note gene silencing via RNA interference also got easier recently http://phys.org/news/2014-02-rna-nature-nanoparticles-best-ever-gene.html
. 9. Human Brain White Matter Connections Mapped.
The first map of core white matter connections in the human brain has been created, showing that not all brain connections are equally important http://pressroom.usc.edu/how-our-brain-networks-research-reveals-white-matter-scaffold-of-human-brain/
. White matter - generally glial cells and myelinated axons - act as crucial relay and communications infrastructure between different brain regions. Such a map helps advise and inform on the likely impact of brain injuries and brain diseases depending on the location of damage in the patient’s brain, and may also be useful and relevant to ongoing brain mapping efforts. 10. Surpassing Unity - A Nuclear Fusion Milestone.
The National Ignition Facility has achieved an order-of-magnitude performance improvement in fusion yield over past experiments and, for the first time, surpassed a fuel-gain greater than unity in which the nuclear fusion energy released was greater than the energy used to trigger fusion https://www.llnl.gov/news/aroundthelab/2014/Feb/NR-14-02-06.html#.UwCzwfmSznQ
. Surpassing unity is a key milestone on the path towards ignition
and a controllable nuclear fusion source of energy. The key innovation was novel shaping of the laser pulse that triggers fusion in the deuterium-tritium implosion, and a harnessing of alpha-particle feedback to accelerate the burn and “run away” to ignition.An archive of the SciTech Digests can also be found here: http://www.scitechdigest.net +ScienceSunday
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