Listen and read 7: Beach Forensics - Thấm Tâm Vy

Nội dung text: Listen and read 7: Beach Forensics - Thấm Tâm Vy

1. LISTEN AND READ 07 This gives each sample of sand two distinct measurements: how quickly the Beach Forensics sound changes pitch, and how much it does so. NAME THAT DUNE Dara Fitzpatrick, a chemist at University College Cork, who developed the The sound of sand reveals its source BARDS technique, says the change, from high notes to low and then back again, Lift a shell from the sand to your ear and everyone knows you can hear the sea. can be heard when many powders dissolve and is known to physicists as the hot- But listen carefully enough and you can hear shells in the sand too. Sand, it turns chocolate effect. “You can do it in your kitchen,” he says. His team is selling the out, has a signature sound of its own, and now scientists have found a way to kit to drug companies as a quicker and cheaper way to analyse powders. It has tune in. also been used to distinguish expensive Himalayan table salt from inferior fakes. To the untrained eye, one bucket of beach sand looks much like another but With sand, the more carbonate there is to produce carbon-dioxide gas, the mixed into the multitude of microscopic minerals are carbonate chemicals left greater the acoustic shift. That is what allows the eavesdropping scientists to behind from the shells of long-dead sea creatures such as molluscs. The pinpoint its source. They can also pick up more subtle influences, including the carbonate concentration varies according to local geology, and Saskia van Ruth, effect of the remains of different-shaped shells, because variations in their a researcher at Wageningen University in the Netherlands, and her colleagues thickness and surface area speed or slow the release of gas. say this leaves each batch of sand with its own distinctive noise. The results Follow the sand could extend forensic techniques, providing a quick way to determine the In places like the Netherlands, forensic tracing could help track the source of disputed sand. effectiveness of coastal-management practices, such as the dumping of millions After water, sand and gravel are the most used natural materials in the world. of tonnes of sand to bolster natural defences against the sea. Where that sand But a looming global shortage has led to a boom in clandestine sand mining and ends up is not always clear. Placing the sand directly onto beaches is believed to even outright theft. In the southern Indian state of Tamil Nadu, authorities are be wasteful because much of it is washed back into the sea. Newer methods drop battling a so-called “sand mafia” who supply the construction industry through the sand into the shallow water just off the beach, allowing the tides to deposit it illegal dredging of riverbanks. Last year Malaysia became the latest country in onto the land over time. Dr Fitzpatrick says existing methods to distinguish sand the region to ban the sale and export of its sand, demand for which has soared as samples are crude and slow as they rely on looking at the size and shape of Singapore seeks to reclaim land from the sea. A decade ago an entire beach, 500 individual grains under a microscope. He sells sea shells as a way to see more. truckloads, was stolen from a resort in northern Jamaica and, it is believed, sold [The Economist, 14.9.2019] to rival operators. Writing in Applied Acoustics, Dr van Ruth’s team show they can distinguish Notes: - forensic techniques: kỹ thuật pháp y between sand samples retrieved (legally) from nine seaside spots along the - beaker : cốc vại Dutch coast. And armed with that information as a reference tool, they could - pinpoint: định vị chính xác - to bolster lót, đỡ, chèn bằng gối, đệm work out which beach a given sand sample had come from. ~( )~ The scientists used a technique called Broad Acoustic Dissolution Spectroscopy ^ analysis (BARDS). It is done with a sensitive listening device that picks up Ageing changes in acoustic properties when a scoop of sand or other powder is dropped REJUVENATION JUICE into a beaker of mild acid and mixed. Chemical changes, including the Uncovering how the body ages is leading to drugs to reverse it breakdown of carbonates to carbon dioxide, release bubbles that increase the In 2006, a startup in California called Ambrosia began offering its customers compressibility of the liquid and therefore slow down the passage of sound startup in California called Amtransfusions of blood from the young. At $8,000 through it. Tap the side of the beaker as the sand and acid are mixed together and per litre, it was a service for the wealthy who believed that young blood could the sound that emerges drops in frequency over time. After a few minutes, all of slow down or reverse the ageing process, thereby reducing their chances of the carbonate is broken down so the production of gas slows and stops. In developing cancers, Alzheimer’s disease and heart disease. Earlier this year response, the frequency of sound passing through the liquid goes back to normal. Thẩm tâm Vy, Sept. 14th, 2019 LISTEN AND READ 07
2. America’s Food and Drug Administration (FDA) cautioned potential customers people age, TGF-beta accretes in the blood and this leads to problems such as that there was no proven scientific benefit to receiving such blood. inflammation or fibrosis. In a new study published in Ageing, Dr Conboy describes a way to slow down In response, Ambrosia shut down its clinics. But ill-fated startups aside, there this damage. Her team gave ageing mice a cocktail of oxytocin, a hormone, and is a kernel of truth to the idea that young blood can be rejuvenating. Experiments ALK5 inhibitor, an enzyme. Previous studies showed that these had positive in the early 2000s in which mice of different ages had been stitched together to effects on some of the symptoms of ageing. By suppressing the amount of TGF- share their circulatory systems, known as heterochronic parabiosis, had beta in cells, the ALK5 inhibitor had been shown to stimulate the growth of new demonstrated dramatic improvements in the cognition, muscle repair and liver brain cells and improve muscle and tissue health. And oxytocin, which activates function of the elderly partners. The race this work sparked to translate the idea stem-cell formation in response to tissue damage or atrophy, declines naturally into something useful to humans, however, raises issues, not least in the with age. squeamishness and hazards associated with sharing blood. However, to have any effects, ALK5 inhibitor usually had to be given at very high doses. And when researchers tried to add extra oxytocin by itself, the hormone’s benefits were overwhelmed by waste accreted in old blood. By putting them together, however, it was possible to reduce the dose of ALK5 inhibitor by a factor of ten and reap the benefits of the oxytocin. After seven days on this cocktail, the mice had less inflammation in their brains, more neural stem cells in the brain area responsible for memory and learning, and better cognitive capacity. Their livers had less scarring and fat, and their muscles healed better and faster. In short, their bodies and brains looked a lot like the old mice after parabiosis—but without the drawbacks of a blood buddy. Because both ingredients of this chemical cocktail are already approved by the FDA, Dr Conboy’s team is now planning a clinical trial of 20 volunteers over 65, to see if the cocktail’s rejuvenating powers will work in people. The latest findings have been welcomed, albeit cautiously. Scientists at the American National Institute on Ageing say the latest work may show a way forward in a field that currently seems stuck. But they think it is too early to advance the research into human trials. The concern is that the drugs being used have not previously been tested together in people. Dr Conboy points out, however, that prescribing approved drugs in multiple combinations is a standard Perhaps no longer. One of the pioneers of parabiosis, Irina Conboy, a procedure in medicine. Entrepreneurs in Silicon Valley might have jumped the bioengineer at the University of California, Berkeley, has now developed a way gun in selling the rejuvenating effects of parabiosis to their clients. Nevertheless, to get some of the benefits of parabiosis without any of the gruesome methods. this vampire-like concept is not gone yet—and could still rise up from the dead She and other scientists in the field had previously found that not only did old someday soon. [The Economist, 14.9.2019] partners benefit from parabiosis, but young partners suffered: the old blood aged Notes: them prematurely. Some of the decline was caused by a protein called - heterochronic parabiosis: đời sống ghép nhờ sự chuyển hóa gen của mô transforming growth factor beta (TGFbeta). This is normally responsible for - squeamishness: sự đắn đo, câu nệ - accretes: cùng phát triển thành một khối regulating everything from cell proliferation to differentiation and death. As - fibrosis: chứng xơ hóa - oxytocin: hormone tuyến yên Thẩm tâm Vy, Sept. 14th, 2019 LISTEN AND READ 07