SciTech #ScienceSunday Digest, 48/14.
Programmed tissue regeneration, microbiome genetics, dimensionality reduction, commercial diamond semiconductors, 3D printed graphene, better synbio circuits, neurocircuit project, self immunity, superomniphobic surfaces, chemical handedness.
1. Latest Advances in Tissue Regeneration via Reprogramming.
Zebrafish hearts regenerate and don’t scar when damaged. A screen of microRNAs in regenerating zebrafish hearts identified those microRNAs (i) whose expression levels changed during regeneration and (ii) were conserved in the mammalian genome. Four promising candidates declined during regeneration and yet were maintained at high levels in damaged mice hearts. When these four microRNAs were targeted and suppressed in the damaged hearts of mice, cardiac cells de-differentiated to an earlier stem-cell-like state and actively helped regenerate the damaged heart, significantly reducing scarring and improving heart wall thickness and pumping ability http://www.salk.edu/news/pressrelease_details.php?press_id=2058. The group plan to move such regenerative reprogramming into larger animals and identify other promising reprogramming targets; the work also brings up the topic of evolutionary conservation of such abilities. In related news nail stem cells are providing additional insights into the latent regenerative abilities of mammals http://stemcell.usc.edu/2014/11/20/nail-stem-cells-prove-more-versatile-than-press-ons/.
2. We’re Symbionts Who Contribute a Minority of Genetic Information.
Building on several consecutive weeks of interesting studies concerning human intestinal flora or microbiome we have a recent study that built the most accurate catalogue ever of genes from microbes residing in the human gut, a catalogue that totalled nearly 10 million genes http://www.alphagalileo.org/ViewItem.aspx?ItemId=147564&CultureCode=en and the paper can be found here http://www.nature.com/nbt/journal/v32/n8/full/nbt.2942.html. While 60% of the genes are shared by just 1% of the human population the implication still seems to be that the amount of genetic information carried by microbes in our guts dwarfs our own genetic repository in terms of number of genes. The catalogue includes close-to-complete sets of most gut microbes and will be an important reference tool for future studies and interventions into the human microbiome for improving human health.
3. Dimensionality Reduction: From Neuroscience to Deep Learning.
Dimensionality reduction is a mathematical or algorithmic process used to simplify complex phenomena while still capturing that complexity reasonably well. The technique is now being applied in neuroscience to enable models that account for single-neuron heterogeneity while offering simple (computable) accounts of how large groups of neurons interact with each other http://motherboard.vice.com/read/neuroscientists-have-a-new-algorithm-for-simplifying-the-brains-deep-complexity. Quote: Linear dimensionality reduction can be used for visualizing or exploring structure in data, denoising or compressing data, extracting meaningful feature spaces, etc. It is ultimately a statistical technique for analysing how large numbers of entities like neurons interact and is more frequently being used to build better machine learning systems in a range of applications.
4. Diamond Semiconductors: Commercial Development.
Diamond semiconductor company Akhan Semiconductor has acquired a portfolio of University-developed diamond semiconductor technologies for the purpose of further development and commercial deployment http://www.anl.gov/articles/argonne-announces-new-licensing-agreement-akhan-semiconductor. Diamond semiconductor technology promises improved performance and thermal efficiency of silicon-based computers and solar cells, and (when doped) can form improved circuit elements such as transistors. Mass adoption and utility has been hampered by manufacturing techniques (see http://www.evincetechnology.com/whydiamond.html for more information) but it seems as though these hurdles are finally being overcome.
5. 3D Printed Graphene Nanostructures.
Free-standing graphene nanostructures can now be 3D printed in complex shapes using a new technique in which a moving nozzle stretches out the ink (graphene oxide plus solvent) as the solvent rapidly evaporates and reduces the size of the dried, hardened graphene filament that remains http://www.nanowerk.com/spotlight/spotid=38253.php. The proof-of-concept involved creating graphene oxide nanowires at room temperature with smallest feature lengths coming in at 150nm, and forming beams, bridges, and suspended & woven structures. The group hope to demonstrate a range of 2D patterns and 3D architectures for various circuit elements, transistors, LEDs, sensors, and photovoltaics, although resolution and scale-up will remain as problems.
6. Improving Stability and Reliability for Biological Circuits.
Biology is messy. Simple biological circuit components exist and are predictable; combining many components together tends to rapidly degrade predictability as complexity increases. To address this problem a team has now created a synthetic biological version of a load driver to provide a buffer between the signal and output and prevent the effects of the signalling from backing up and interfering with the circuit and its outputs http://newsoffice.mit.edu/2014/predictable-biological-circuits-1124. This is an important tool contributed to the library of synthetic biology tools, and will enable the creation of much more complex and useful genetic circuits that are reliable and predictable, e.g. sensing and responding to insulin or cancer or undesirable tissue environments, etc.
7. NeuroCircuit: Non-Invasive Treatments for Mental Illness.
The NeuroCircuit project aims to develop (i) a systematic understanding of what brain circuits underlie which specific mental illnesses and (ii) non-invasive interventions to target and alter those circuits to treat the mental illness http://news.stanford.edu/news/2014/november/neurocircuit-mental-illness-112514.html. The interventions being explored to alter the behaviour of circuits will consist initially of transcranial magnetic stimulation to target cortical brain tissue close to the surface and also directed ultrasound to target deeper regions of the brain. The hope is that such interventions will also generate far fewer side effects by specifically targeting the circuits responsible and avoiding systemic effects across the body and whole brain as caused by current pharmaceutical interventions.
8. The Specifics of Immunological Self-Recognition.
A study this week shed light on the specific mechanism by which our innate immune system distinguishes cells the make up the body and those that are foreign and need to be attacked http://phys.org/news/2014-11-biochemists-molecular-immune-friend-foe.html. Sialic acid has been known for decades to play an important role in this process but it was only recent high-resolution structural analysis that revealed the specific way in which specific proteins of our innate immune system recognise and bind to sialic acid, found on the surface of all of our cells, and so preventing an immune cascade. Some pathogenic bacteria have evolved to exploit this mechanism to try and avoid immune recognition (and which our body deals with in other ways) but I wonder if there are efforts to exploit this mechanism to our own gain for example to protect implanted medical devices from being attacked by our immune system?
9. Superomniphobic Textures Repel All Fluids.
A newly designed surface texture is able to repel all fluids it comes in contact with no matter what material the underlying surface itself is made of http://phys.org/news/2014-11-superomniphobic-texture-capable-repelling-liquids.html. The patterned surfaces are comprised of flathead nail structures about 20 micrometers in diameter whose heads employ an overhang structure, and proved it’s superomniphobic repelling properties on surfaces made of glass, metal, and polymer. The group demonstrated the surfaces repelling all fluids including water, oils, and solvents. It even worked on perfluorohexane – the liquid with the lowest lowest known surface tension – sitting on a bed of 95% air enabled by the surface and being held together as a droplet by its own surface tension. The embedded videos are worth checking out.
10. Insights into Chemical Handedness.
For the first time a solution of molecules of all the same handedness has been produced from simple starting materials in a single vessel http://phys.org/news/2014-11-molecules-handy-life-earth.html. Synthetic chemical reactions to produce even basic organic molecules typically create a solution of equal left- and right-handed molecules that are the mirror image of each other. And yet all life on Earth appears to be right-handed; DNA employs a right-handed helix and basic sugar is right-handed. Despite being chemically identical, given the handedness of life the biological effects of mirrored molecules can be very different – such as in the case of Thalidomide tragically demonstrating the importance of getting handedness right. The researchers here demonstrated spontaneous asymmetric synthesis for the first time, a process that may have industrial applications and also shed light on how the handedness of life arose on Earth.
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