New method for dieting: Brain control

The sense of hunger and feeling of satiation after eating are mediated by cells in the lower part of the hypothalamus in the brain. Scientists have found ways to remotely activate and inhibit this region specifically without any surgical intervention. Genetically encoded nanoparticles that respond to radio signals of magnetic stimulation were used to activate glucose-sensing neurons in the ventromedial hypothalamus of live rats. This was found to increase plasma glucose and glucagon, lower insulin levels and stimulate feeding. Inhibition reduces blood glucose, raises insulin levels and suppresses feeding.

So, if you have been planning to diet and never got around to doing it yet, wait for some more time. The technique demonstrated in the lab might soon be around since there is enough demand.

Nature 531, 647–650 (31 March 2016)

Mobile Phones to Measure Tidal Forces

Many cell phones today have microelectromechanical systems that can detect acceleration. By tweaking the system a little, these devices can detect acceleration due to gravity, claims a paper in a recent issue of Nature.

The new device is sensitive enough to detect tidal forces on earth. From being a mere accelerometer, it becomes a gravimeter that can measure tidal forces.

Most present gravimeters are heavy. But this new device is so light that you can use it on a drone and let it survey the land. It will give you clues about underground reservoirs of oil, magma etc.

By putting the device into handphones, and crowdsourcing the data while people travel around, we will be able to map what lies underground.

Nature 531, 614–61(31 March 2016)

Unpunished corruption leads to more corruption

In our society, many cases of corruption go unpunished. Prevalence of rule violations (corruption, tax evasion etc.) tends to reduce intrinsic honesty in young people, says a recent paper in Nature.

More than 2500 young people from 23 countries took part in the experiment. Researchers conclude that

"weak institutions and cultural legacies that generate rule violations not only have direct adverse economic consequences, but might also impair individual intrinsic honesty that is crucial for the smooth functioning of society".

The message is clear: if you want to reduce corruption and tax evasion, punish the guilty and let the public know that economic offences will not be tolerated. This would have implications on lying and dishonest behaviour even in other realms of day-to-day life.

Regeneration of Lens after Cataract Operation

In the latest issue of Nature, there is a report of lens regeneration after cataract operation. Till now this was thought to be impossible. But Chinese and US scientists joined hands to prove that it is indeed possible. The trick is simple enough: when you remove the lens, be careful not to remove stem cells. But in practice, it requires a totally different operating procedure. Scientists find that if they retain cells that express Pax6 and Bmi1 genes, lens does regenerate and visual function is restored.

They first did experiments on rabbits and macaques. And they demonstrated that the same procedure works in human infants with cataract.

Cataract is one of the leading causes of blindness. The finding that it is feasible to allow the lens to regenerate using endogenous cells may revolutionise cataract operations.