Zurich

New non-smokers may gain weight because of gut changes, not food.

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Eighty percent of people who quit smoking put on an average of 15 pounds, studies have shown, and those pounds are usually attributed to a person trading lighting up for pigging out. But according to the researchers at the Zurich University Hospital, the weight gain may not have to anything to do with an increase in calories. Rather, the weight might be a result of changes in the composition of a person’s intestinal flora after they quit. The study found that when a person stops smoking, the bacteria in their intestinal flora shifts to a type which burns energy more efficiently and breaks down more of what is ingested, thus creating more fat and less waste. The 20 study participants insisted their calorie intake stayed the same or fell after they quit smoking.

 smoke

Source:MSN

Are IBD and GI Infections Worse During Heat Waves?

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In a large, observational study, hospitalizations for inflammatory bowel disease and infectious gastroenteritis increased with heat-wave durations.
Heat waves are associated with increases in mortality, commonly reported in patients who are sick or elderly. To examine the effect of heat waves on inflammatory bowel disease (IBD) and infectious gastroenteritis (IG), investigators conducted a retrospective, observational study involving 2030 patients admitted to the University Hospital of Zurich with IBD (738 patients), IG (786 patients), or non-IBD, noninfectious intestinal inflammation (NII; 506 controls). The study period was from 2001 through 2005, during which there were 17 heat waves, defined as ≥6 consecutive days with temperatures ≥9 degrees Fahrenheit above the average daily maximum.

Admissions for IBD rose 34.4% overall during heat-wave periods and 4.6% for each additional day of a heat wave. Admissions for IG, which was not distinguished as bacterial or viral, rose 34.8% overall during heat-wave periods and 4.7% for each additional day of a heat wave; however, the maximum increase in admissions per day was estimated at 7.2% when a 7-day lag in the development of IG was considered. No such lag effect was observed with IBD. NII controls experienced no increase in hospital admissions during the heat waves.

COMMENT

Presumably, the increases in hospitalizations for infectious gastroenteritis are related to greater environmental growth of pathogens with higher temperatures. The cause of the increase in inflammatory bowel disease hospitalizations is uncertain, and could reflect increased physical stress associated with heat, changes in growth rates of infectious pathogens, or other factors.

Source: NEJM.

Sound Waves Levitate and Move Objects.

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A new approach to contact-free manipulation could be used to combine lab samples–and prevent contamination

Water droplets, coffee granules, fragments of polystyrene and even a toothpick are among the items that have been flying around in a Swiss laboratory lately — all of them kept in the air by sound waves. The device that achieves this acoustic levitation is the first to be capable of handling several objects simultaneously. It is described today in theProceedings of the National Academy of Sciences.

Typically, levitation techniques make use of electromagnetism; magnetic forces have even been used to levitate frogs. It has long been known that sound waves could counter gravity, too, but so far the method has lacked practical application because it could do little more than keep an object in place.

To also move and manipulate levitating objects, Dimos Poulikakos, a mechanical engineer at the Swiss Federal Institute of Technology (ETH) in Zurich, and his colleagues built sound-making platforms using piezoelectric crystals, which shrink or stretch depending on the voltage applied to them. Each platform is the size of a pinky nail.

The platforms emit sound waves which move upward until they reach surface lying above, where they bounce back. When the downward-moving reflected waves overlap with the upward-moving source waves, the two ‘cancel out’ in the middle, at so-called node points. Objects placed there remain stuck in place because of the pressure of sound waves coming from both directions.

By adjusting the position of the nodes, the researchers can tow the objects between platforms. The platforms can be arranged in different ways to adapt to various experiments. In one demonstration involving a T-shaped array of platforms, the researchers joined two droplets introduced at separate locations then deposited the combined droplet at a third location.

Hands-free reactions
The system could be used to combine chemical reactants without the contamination that can result from contact with the surface of a container. Sound waves are already used in the pharmaceutical industry to obtain accurate results during drug screening. Yet Poulikakos’s method is the first to offer the possibility of precisely controlling several items simultaneously.

Poulikakos suggests that the system could be used to safely try out hazardous chemical reactions. “We had fun demonstrating the idea by colliding a lump of sodium with some water, which is obviously an aggressive reaction,” he says.

Peter Christianen, a physicist who works on electromagnetic levitation at Radboud University in Nijmegen, the Netherlands, says that he’s impressed with the invention. “I really like it; this is a very versatile platform — almost anything you want to manipulate, you can.”

Source: Scientific American

 

Atomic bonds between their atoms .

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A pioneering team from IBM in Zurich has published single-molecule images so detailed that the type of atomic bonds between their atoms can be discerned.

The same team took the first-ever single-molecule image in 2009 and more recently published images of a molecule shaped like the Olympic rings.

The new work opens up the prospect of studying imperfections in the “wonder material” graphene or plotting where electrons go during chemical reactions.

The team, which included French and Spanish collaborators, used a variant of a technique called atomic force microscopy, or AFM.

AFM uses a tiny metal tip passed over a surface, whose even tinier deflections are measured as the tip is scanned to and fro over a sample.

The IBM team’s innovation to create the first single molecule picture, of a molecule called pentacene, was to use the tip to pick up a single, small molecule made up of a carbon and an oxygen atom.

This carbon monoxide molecule effectively acts as a record needle, probing with unprecedented accuracy the very surfaces of atoms.

It is difficult to overstate what precision measurements these are.

The experiments must be isolated from any kind of vibration coming from within the laboratory or even its surroundings.

They are carried out at a scale so small that room temperature induces wigglings of the AFM’s constituent molecules that would blur the images, so the apparatus is kept at a cool -268C.

While some improvements have been made since that first image of pentacene, lead author of the Science study, Leo Gross, told BBC News that the new work was mostly down to a choice of subject.

The new study examined fullerenes – such as the famous football-shaped “buckyball” – and polyaromatic hydrocarbons, which have linked rings of carbon atoms at their cores.

The images show just how long the atomic bonds are, and the bright and dark spots correspond to higher and lower densities of electrons.

Together, this information reveals just what kind of bonds they are – how many electrons pairs of atoms share – and what is going on chemically within the molecules.

“In the case of pentacene, we saw the bonds but we couldn’t really differentiate them or see different properties of different bonds,” Dr Gross said.

“Now we can really prove that… we can see different physical properties of different bonds, and that’s really exciting.”

The team will use the method to examine graphene, one-atom-thick sheets of pure carbon that hold much promise in electronics.

But defects in graphene – where the perfect sheets of carbon are buckled or include other atoms – are currently poorly understood.

The team will also explore the use of different molecules for their “record needle”, with the hope of yielding even more insight into the molecular world.

Source: BBC