Showing posts with label mechanism. Show all posts
Showing posts with label mechanism. Show all posts

Thursday, March 22, 2012

Hublot Antikythera mechanism,100-year-old clockwork relic

It's a story of gigantic scientific upheaval, of adventure and shipwreck on the high seas, of war and death.

A story of amazing intellect, lost riches and impossible chance - a sunken treasure that Jaques Cousteau once described as "more valuable than the Mona Lisa" - and it's connected with an ancient celebrity whose star shone so brightly that he's still a household name more than 2200 years after his death.

There are few scientific or historic discoveries more significant than the one made by a Greek sponge diver in October 1900, on the Mediterranean sea bed.

Captain Kondos sent a team down to see if they might be able to pick up any more sponges while they waited for the storm to pass.

Within a short time, diver Elias Stadiatos resurfaced, raving like a lunatic. He reported finding a shipwreck on the sea bed 60 meters (197 feet) below, with hundreds of corpses and horses strewn about, in various stages of decay.

Far from a stack of corpses, what Kondos found made his sponge gathering mission pale in comparison.

A sunken ancient vessel, loaded with all kinds of loot and treasure. What Stadiatos had reported as rotting bodies were actually bronze statues that had been covered over by centuries' worth of sea floor debris.

The team scavenged what they could carry and took it back to Greece, where the Greek Education Ministry and Hellenic Navy quickly put together an expedition to explore the wreck more thoroughly.

Early indications were that the material on board dated back more than 2,000 years, into the fascinating historical period of the Roman Republic.

The collection itself was a celebrated find, but one anonymous chunk of rock sitting in a storage room had further riches to offer, when it broke apart and a caretaker noticed metallic gears within.

The Antikythera mechanism
Historians at the time largely ignored the device for one simple reason - the technology required to make such complex metallic gear systems simply didn't exist back in 100 B.C.

It appeared to have an epicyclic, or planetary gear system in it - and those hadn't popped up anywhere else in history for another 1900 years or so.

It was assumed that the machine had been misplaced, accidentally left with the wreckage, or wrongly catalouged, so it was shelved for another 49 years, until an English physicist called Derek Price decided to have a closer look in 1951.

With better technology and plenty of time at hand, Price soon realized that this was indeed an ancient device - in fact, there was some kind of instructive script carved into it, faded almost to obscurity, that put it right in the 100-300 B.C. period. This was a true Eureka moment - it put amazingly advanced technology in the hands of the Ancient Greeks.

In fact, it instantly became not only the world's earliest known use of planetary gears, but the first known mechanism that used clockwork gears at all. Various civilizations earlier than the Ancient Greeks had used wooden peg-in-hole gear systems to transfer motion, but this was an order of magnitude more complex than anything before it, and indeed anything for a millennium and a half after it.

Read More here

Tuesday, December 14, 2010

Mechanism Boasts Memory: Neuropeptide S

In collaboration with scientists at Germany's University of Munster, the UC Irvine team found that a small protein called neuropeptide S can strengthen and prolong memories of everything from negative events to simple objects.

According to study leader Rainer Reinscheid, UCI associate professor of pharmaceutical sciences, the discovery could provide important clues about how the brain stores memories and also lead to new treatments for Alzheimer's disease, dementia and other cognitive impairments.

"Additionally, it may help us better understand post-traumatic stress disorder, which involves exaggerated memories of traumatic events," he said.

In tests on mice, the researchers observed that if neuropeptide S receptors in the brain were activated immediately after a learning experience, it could be recalled for much longer and with much greater intensity.

This memory enhancement lasted up to a week, Reinscheid said, but when NPS receptor activation was disrupted, the mice didn't remember events as strongly -- if at all -- when tested just a day or two later.

Study results, which appear in the journal Neuro-psycho-pharmacology, are in accordance with Reinscheid's previous findings that NPS causes wakefulness and has a calming effect.

"It appears that the combination of increased alertness and reduced anxiety produced by NPS prepares the animals to learn much better," he said. "Memory is remarkably improved after activation of their NPS system, and the effects are long-lasting, independent of content."

Naoe Okamura, Celia Garau, Dee Duangdao and Stewart Clark of UCI as well as Kay Jungling and Hans-Christian Pape of the University of Munster contributed to the study, which was funded in part by the National Institute of Mental Health.

Thursday, December 9, 2010

Natural drug Abscisic Acid's infection fighting mechanism revealed

The scientists had reported some of the key molecular events in the immune system of mice that contribute to inflammation-related disease, including the involvement of a specific molecule found on the surface of immune cells involved in the body’s fight against infection (http://www.ncbi.nlm.nih.gov/pubmed/21068720). 

They have now gone one step further and revealed the mechanism by which the natural drug abscisic acid interacts with this protein, known as peroxisome proliferator-activated receptor-gamma, to block inflammation and the subsequent onset of disease.

“In previous work, our research group demonstrated that abscisic acid has beneficial effects on several conditions and diseases including obesity-related inflammation, diabetes, atherosclerosis, and inflammatory bowel disease,” said Josep Bassaganya-Riera, associate professor of immunology at the Virginia Bioinformatics Institute, leader of the Nutritional Immunology and Molecular Medicine Group in the institute’s CyberInfrastructure Division, and principal investigator of the study.

“One idea for how abscisic acid reduces inflammation in these instances is that it binds to a special region of peroxisome proliferator-activated receptor-gamma, a binding site known as the ligand-binding domain where the drug would be expected to latch on to and exert its effect. 

Our results show that this is not the case and, for the first time, we have demonstrated that abscisic acid works independently of this ligand-binding domain of the receptor.”

More information on this article here Science Blog

Thursday, July 29, 2010

Mechanism uncovered behind Salmonella virulence and drug susceptibility

Researchers have discovered a novel mechanism in Salmonella that affects its virulence and its susceptibility to antibiotics by changing its production of proteins in a previously unheard of manner. This allows Salmonella to selectively change its levels of certain proteins to respond to inhospitable conditions.

Although the mechanism had not been recognized before, the scientists were intrigued to find evidence of a similar mechanism in all five kingdoms of life — animals, plants, fungi, protista, and monera.

The findings were published today, July 29, in Molecular Cell. The senior author of the study is Dr. Ferric C. Fang, professor of microbiology, laboratory medicine, and medicine at the University of Washington (UW). Fang also directs the Clinical Microbiology Laboratory at Harborview Medical Center in Seattle. The lead author is William Wiley Navarre, who began the study as a postdoctoral fellow in the Fang lab and is now an assistant professor at the University of Toronto.

Salmonella enters the gut when people eat contaminated food, and can sometimes spread to other parts of the body. Illness outbreaks and grocery recalls related to Salmonella are often in the news. Babies, young children, the elderly, and people with cancer or HIV are especially prone to severe illness from Salmonella.

Salmonella is adaptable and can withstand many of the body’s attempts to fight it. The bacteria live and multiply in a special compartment inside the cells of an infected person or animal. Salmonella can alter its physiology as it moves from a free-swimming life to its residence in a host cell. Salmonella’s metabolism also changes over time to make use of the nutrients available in the host cell, and to survive damage from the build-up of oxidants and nitric oxide in the infected cell.

While screening mutant Salmonella that were resistant to a form of nitric oxide that normally stops the bacteria from dividing, Navarre, Fang and their research collaborators found mutations in two little-known genes. These are the closely linked poxA and yjeK genes. In a number of bacteria, these two genes are associated with a third gene that encodes the Bacterial Elongation Factor P, which is involved in protein production.

The researchers discovered that these three genes operate in a common pathway that is critical for the ability of the Salmonella bacteria to cause disease and resist several classes of antibiotics. Salmonella with mutations in either the poxA gene or the yjeK genes, the study noted, appear to be nearly identical and show similar changes in proteins involved in metabolism. Strains with mutations in both genes resemble the single mutant strains, an observation that suggests the two genes work in the same pathway.

The mutant strains exhibited many abnormalities under stressful conditions.

Tuesday, May 18, 2010

Research discover mechanism for stress resilience

Scientists have discovered a mechanism that helps to explain resilience to stress, vulnerability to depression and how antidepressants work.

The new findings, in the reward circuit of mouse and human brains, have spurred a high tech dragnet for compounds that boost the action of a key gene regulator there, called deltaFosB.

A molecular main power switch -- called a transcription factor -- inside neurons, deltaFosB turns multiple genes on and off, triggering the production of proteins that perform a cell's activities.

"We found that triggering deltaFosB in the reward circuit's hub is both necessary and sufficient for resilience; it protects mice from developing a depression-like syndrome following chronic social stress," explained Eric Nestler, M.D., of the Mount Sinai School of Medicine, who led the research team, which was funded by the National Institute of Health's National Institute of Mental Health (NIMH).

"Antidepressants can reverse this social withdrawal syndrome by boosting deltaFosB. Moreover, deltaFosB is conspicuously depleted in brains of people who suffered from depression. Thus, induction of this protein is a positive adaptation that helps us cope with stress, so we're hoping to find ways to tweak it pharmacologically," added Nestler, who also directs the ongoing compound screening project.

Nestler and colleagues report the findings that inspired the hunt online May 16 2010 in the journal Nature Neuroscience.

Wednesday, July 29, 2009

World's first computer; Like Grandad, older than you thought

antik1.jpg From Swiss Army knives to iPhones, it seems we just love fancy gadgets with as many different functions as possible. And judging from the ancient Greek Antikythera mechanism, the desire to impress with the latest multipurpose must-have item goes back at least 2000 years.

Clockwork Computer
This mysterious box of tricks was a portable clockwork computer, dating from the first or second century BC. Operated by turning a handle on the side, it modelled the movements of the Sun, Moon and planets through the sky, sported a local calendar, star calendar and Moon-phase display, and could even predict eclipses and track the timing of the Olympic games.

The Origin
One new clue to the origin of the mechanism comes from the Olympiad dial, there are six sets of games named on the dial, five of which have been deciphered so far. Four of them, including the Olympics, were major games known across the Greek world but the fifth, Naa, was much smaller, and would only have been of local interest.

The Naa Games
The Naa games were held in Dodona in northwestern Greece, so Alexander Jones of the Institute for the Study of the Ancient World in New York has suggested that the mechanism must have been made by or for someone from that area.

Older than the Romans
Intriguingly, this could mean the device is even older than at first thought. The inscriptions have been dated to around 100 BC, but according to Jones the device may have been made at latest in the early second century BC, because after that the Romans devastated or took over the Greek colonies in the region, so it's unlikely that people would still have been using the Greek calendar there.

Highlights
The highlight for most audiences, was this breathtaking new animation (Click on the Picture) of the gearing inside the mechanism. It has been made by Mogi Vicentini, an Italian astronomer and computer scientist, and it brings the device to life brilliantly.



Judge for yourself. It shows that the mechanism would hold its own against the best of today's luxury gadgets.