how long until this is implantable...

Ars Technica | IBM creates world’s first artificial phase-change neurons

IBM Research in Zurich has created the world's first artificial nanoscale stochastic phase-change neurons. IBM has already created a population of 500 of these artificial neurons and used them to process a signal in a brain-like (neuromorphic) way.

This breakthrough is particularly notable because the phase-change neurons are fashioned out of well-understood materials that can scale down to a few nanometres, and because they are capable of firing at high speed but with low energy requirements. Also important is the neurons' stochasticity—that is, their ability to always produce slightly different, random results, like biological neurons.

Enough fluff—let's talk about how these phase-change neurons are actually constructed. At this point, it might help if you look at the first diagram in the gallery.

...Like a biological neuron, IBM's artificial neuron has inputs (dendrites), a neuronal membrane (lipid bilayer) around the spike generator (soma, nucleus), and an output (axon). There's also a back-propagation link from the spike generator back to the inputs, to reinforce the strength of some input spikes.

The key difference is in the neuronal membrane. In a real neuron, this would be a lipid bilayer, which essentially acts as both a resistor and a capacitor: it resists conductance, but eventually, with enough electricity along the input dendrite, it builds up enough potential that its own spike of electricity is produced—which then flows along the axons to other neurons—and so on and on.

In IBM's neuron, the membrane is replaced with a small square of germanium-antimony-tellurium (GeSbTe or GST). GST, which happens to be the main active ingredient in rewritable optical discs, is a phase-change material. This means it can happily exist in two different phases (in this case crystalline and amorphous), and easily switch between the two, usually by applying heat (by way of laser or electricity). A phase-change material has very different physical properties depending on which phase it's in: in the case of GST, its amorphous phase is an electrical insulator, while the crystalline phase conducts.

With the artificial neurons, the square of GST begins life in its amorphous phase. Then, as spikes arrive from the inputs, the GST slowly begins to crystallise. Eventually, the GST crystallises enough that it becomes conductive—and voilà, electricity flows across the membrane and creates a spike. After an arbitrary refractory period (a resting period where something isn't responsive to stimuli), the GST is reset back to its amorphous phase and the process begins again.

would you? i just might...

Quillette | The Future of Genetic Enhancement is Not in the West

Would you want to alter your future children’s genes to make them smarter, stronger or better-looking? As the state of the science brings prospects like these closer to reality, an international debate has been raging over the ethics of enhancing human capacities with biotechnologies such as so-called smart pills, brain implants and gene editing. This discussion has only intensified in the past year with the advent of the CRISPR-cas9 gene editing tool, which raises the specter of tinkering with our DNA to improve traits like intelligence, athleticism and even moral reasoning.

So are we on the brink of a brave new world of genetically enhanced humanity? Perhaps. And there’s an interesting wrinkle: It’s reasonable to believe that any seismic shift toward genetic enhancement will not be centered in Western countries like the U.S. or the U.K., where many modern technologies are pioneered. Instead, genetic enhancement is more likely to emerge out of China.

another energy gradient to harvest

ars technica | Single-atom-thick sheets efficiently extract electricity from salt water

It's possible to generate energy using nothing but the difference between fresh and salt water. When fresh and salt water are separated by a membrane that blocks the passage of certain ions, there is a force that drives the freshwater into the salt water to even out the salt concentration. That force can be harvested to produce energy, an approach termed "osmotic power."

But the generation of osmotic power is highly dependent on how quickly ions can cross the membrane—the thicker (and more robust) the membrane, the slower the ions will flow. Theoretically, the most efficient osmotic power generation would come from an atomically thin membrane layer. But can this theoretical system be achieved here in reality?

Recently, scientists answered that question using atomically thin membranes composed of molybdenum-disulfide (MoS2). In the paper that resulted, they describe a two-dimensional MoS2membrane containing a single nanopore, which was used to separate reservoirs containing two solutions with different concentrations of salt in order to generate osmotic power.

playing g.o.d. - looking forward to the long-term consequences of this trial

The Guardian | Crispr: Chinese scientists to pioneer gene-editing trial on humans

A team of Chinese scientists will be the first in the world to apply the revolutionary gene-editing technique known as Crispr on human subjects.

Led by Lu You, an oncologist at Sichuan University’s West China hospital in Chengdu, China, the team plan to start testing cells modified with Crispr on patients with lung cancer in August, according to the journal Nature.

Crispr is a game-changer in bioscience; a groundbreaking technique which can find, cut out and replace specific parts of DNA using a specially programmed enzyme named Cas9. Its ramifications are next to endless, from changing the color of mouse fur to designing malaria-free mosquitoes and pest-resistant crops to correcting a wide swath of genetic diseases like sickle-cell anaemia in humans.

The concept of editing human DNA has often been controversial. In the UK, genetic modification in humans remains off-limits. Peter Mills, assistant director of the UK Nuffield Council on Bioethics, has told the Guardian of the worries it raises about playing god and “designer babies”. 

A study on non-viable human embryos, also conducted in China, was called off after researchers found what they described as “serious obstacles” to using the method in a clinical setting.

And in March 2015 a group of researchers published an open letter in Nature saying that there were “grave concerns” about the ethical and safety implications of editing the “germ-line” in human genes – the genetic code which is passed on.

Crispr: is it a good idea to ‘upgrade’ our DNA?

 

Read more

The Sichuan University trial, it is important to note, does not edit the germ-line; its effects will not be hereditary.

What the researchers plan to do is enroll patients with metastatic non-small cell lung cancer, Nature reported, and for whom other treatment options – including chemotherapy and radiotherapy – have failed.

They will then extract immune cells from the patients’ blood and use Crispr to add a new genetic sequence which will help the patient’s immune system target and destroy the cancer. The cells will then be re-introduced into the patients’ bloodstream.

this is how you build your nanomachines

Science | Designed to assemble

Symmetric macromolecular structures that form cages, such as viral capsids, have inspired protein engineering. Bale et al. used pairwise combinations of dimeric, trimeric, or pentameric building blocks to design two-component, 120-subunit protein complexes with three distinct icosahedral architectures. The capsid-like nanostructures are large enough to hold nucleic acids or other proteins, and because they have two components, the assembly of cargoes such as drugs and vaccines can be done in a controlled way.

bacteria can't exactly be classified as finite state machines...

Science | Building a computing system in bacteria

Finite state machines are logic circuits with a predetermined sequence of actions that are triggered depending on the starting conditions. They are used for a variety of devices and biological systems, from vending machines to neural circuits. Roquet et al. have taken a finite state machine approach to control the expression of integrases, or enzymes that insert or excise phage DNA into or out of bacterial chromosomes. The integrases altered the DNA sequence of a plasmid to record all five possible combinations of two inputs. Such circuits can be used to record the states that the cell experienced over time and can be deployed in state-dependent gene expression programs.

big pharma none too happy about this...

Washington Post | There's a body of research showing that painkiller abuse and overdose are lower in states with medical marijuana laws. These studies have generally assumed that when medical marijuana is available, pain patients are increasingly choosing pot over powerful and deadly prescription narcotics. But that's always been just an assumption.

Now a new study, released in the journal Health Affairs, validates these findings by providing clear evidence of a missing link in the causal chain running from medical marijuana to falling overdoses. Ashley and W. David Bradford, a daughter-father pair of researchers at the University of Georgia, scoured the database of all prescription drugs paid for under Medicare Part D from 2010 to 2013.

They found that, in the 17 states with a medical-marijuana law in place by 2013, prescriptions for painkillers and other classes of drugs fell sharply compared with states that did not have a medical-marijuana law. The drops were quite significant: In medical-marijuana states, the average doctor prescribed 265 fewer doses of antidepressants each year, 486 fewer doses of seizure medication, 541 fewer anti-nausea doses and 562 fewer doses of anti-anxiety medication.

But most strikingly, the typical physician in a medical-marijuana state prescribed 1,826 fewer doses of painkillers in a given year.

These conditions are among those for which medical marijuana is most often approved under state laws. So as a sanity check, the Bradfords ran a similar analysis on drug categories that pot typically is not recommended for — blood thinners, anti-viral drugs and antibiotics. And on those drugs, they found no changes in prescribing patterns after the passage of marijuana laws.