题目内容
关于无差异曲线的特征的说法，错误的是______。
查看答案
搜索结果不匹配？点我反馈
更多问题
Smoking causes wrinkles by upsetting the body" s mechanism for renewing skin, say scientists in Japan. Dermatologists say the finding confirms the long-held view that smoking ages skin prematurely. Skin stays healthy and young-looking because of a fine balance between two processes that are constantly at work. The first breaks-down old skin while the second makes new skin. The body breaks down the old skin with enzymes called matrix metalloproteinases, or MMPs, They chop up the fibers that form collagen(胶原质)—the connective tissue that makes up around 80 percent of normal skin. Akimichi Morita and his colleagues at Nagoya City University Medical School suspected that smoking disrupted the body" s natural process of breaking down old skin and renewing it. To test their idea, they first made a solution of cigarette smoke by pumping smoke through a saline(盐的)solution. Smoke was sucked from cigarettes for two seconds every minute. Tiny drops of this smoke solution were added to dishes of human fibroblasts, the skin cells that produce collagen. After a day in contact with smoke solution, the researchers tested the skin cells, to see how much collagen-degrading MMP they were making. Morita found that cells exposed to cigarette smoke had produced far more MMP than normal skin cells. Morita also tested the skin cells to see how much new collagen they were producing. He found that the smoke caused a drop in the production of fresh collagen by up to 40 percent. He says that this combined effect of degrading collagen more rapidly and producing less new collagen is probably what causes premature skin ageing in smokers, in both cases, the more concentrated the smoke solution the greater the effect on collagen. " This suggests the amount of collagen is important for skin ageing," he says. "It looks like less collagen means more wrinkle formation". Morita doesn" t know if this is the whole story of why smokers have more wrinkles. But he plans to confirm his findings by testing skin samples from smokers and non-smokers of various ages to see if the smoking has the same effect on collagen. "So far we" ve only done this in the lab. " he says. " We don"t know exactly what happens in the body yet that might take some time. " Other dermatologists are impressed by file work. "This is fascinating," says Lawrence Parish. Director of the Centre for International Dermatology at Thomas Jefferson University Hospital in Philadelphia. This confirms scientifically what we"ve long expected, he says. "Tobacco smoke is injurious to skin. " Monrita implies that his findings______.
Today, I sit in a surgical ICU beside my favorite Jack as he recovers from a five-hour operation to repair a massive aortic aneurysm. For me it has been a journey into the medical system as an inexperienced consumer rather than in my usual position as a seasoned provider. This journey to an urban referral center has produced some disappointing surprises for Dad, and especially for me. For the past two days, my beloved Jack has been called "Harold"(his first name; Jack is his middle name). Of course, there is nothing wrong with "Harold"—it was what he was called in the army— but Dad never has been "Harold" except to those who really don"t know him. Telephone callers at our family home who asked for "Harold" were always red flags that the caller was a telemarketer or insurance salesperson. Dad doesn" t correct his physicians or the office receptionists—he is from the old school, where it is impolite to question or correct your physician. Once he was an almost ideal "Jack," strong, athletic, quietly confident and imminently trustworthy, but his recent renal failure and dialysis treatments , his stroke and his constant tremor have robbed him of his strength, mobility, and golf game, but not of his will or love of his family, part of the reason he agreed to undertake this risky operation at his advanced age was because his wife and sisters still need his protective support. With so much at risk, he faced this life-threatening challenge in a city far away from his home and friends and in a place where he is greeted as "Harold. " The author describes his" Jack" in a tone of______.
Smoking causes wrinkles by upsetting the body" s mechanism for renewing skin, say scientists in Japan. Dermatologists say the finding confirms the long-held view that smoking ages skin prematurely. Skin stays healthy and young-looking because of a fine balance between two processes that are constantly at work. The first breaks-down old skin while the second makes new skin. The body breaks down the old skin with enzymes called matrix metalloproteinases, or MMPs, They chop up the fibers that form collagen(胶原质)—the connective tissue that makes up around 80 percent of normal skin. Akimichi Morita and his colleagues at Nagoya City University Medical School suspected that smoking disrupted the body" s natural process of breaking down old skin and renewing it. To test their idea, they first made a solution of cigarette smoke by pumping smoke through a saline(盐的)solution. Smoke was sucked from cigarettes for two seconds every minute. Tiny drops of this smoke solution were added to dishes of human fibroblasts, the skin cells that produce collagen. After a day in contact with smoke solution, the researchers tested the skin cells, to see how much collagen-degrading MMP they were making. Morita found that cells exposed to cigarette smoke had produced far more MMP than normal skin cells. Morita also tested the skin cells to see how much new collagen they were producing. He found that the smoke caused a drop in the production of fresh collagen by up to 40 percent. He says that this combined effect of degrading collagen more rapidly and producing less new collagen is probably what causes premature skin ageing in smokers, in both cases, the more concentrated the smoke solution the greater the effect on collagen. " This suggests the amount of collagen is important for skin ageing," he says. "It looks like less collagen means more wrinkle formation". Morita doesn" t know if this is the whole story of why smokers have more wrinkles. But he plans to confirm his findings by testing skin samples from smokers and non-smokers of various ages to see if the smoking has the same effect on collagen. "So far we" ve only done this in the lab. " he says. " We don"t know exactly what happens in the body yet that might take some time. " Other dermatologists are impressed by file work. "This is fascinating," says Lawrence Parish. Director of the Centre for International Dermatology at Thomas Jefferson University Hospital in Philadelphia. This confirms scientifically what we"ve long expected, he says. "Tobacco smoke is injurious to skin. " As inferred from Morita" s results, smoking______.
Women find a masculine face—with a large jaw and a prominent brow—-more attractive when they are most likely to attractive, according to a study published in the June 24 NATURE. Before, during, and use after menstruation, however, they seem to be drawn to less angular, more "feminine" male faces, the researchers report. " Other studies of female preference, mainly for odors, show changes across the menstrual cycle ," says lead author Ian Penton-Voak of the University of St. Andrews in Scotland. " We thought it would be interesting to look at visual preferences and see if they changed also". The researchers showed 39 Japanese women composite male faces that emphasized masculine or feminine facial features to differing degrees. The women preferred images with more masculine features when they were in the fertile phase of their menses but favored more feminine features during their less fertile phase. The type of face women find attractive also seems to depend on the kind of relationship they wish to pursue, according to another experiment. The cyclic preference for muscular faces was evident among 23 British women asked to choose the most attractive face for a short-term relationship, Penton-Voak says. The 26 women asked to choose an attractive face for a long-term relationship, however, preferred the more feminine features throughout their menstrual cycle. Another 22 women who were using oral contraceptives did not show monthly changes in the faces they preferred even for short-term relationships, indicating that hormones might play a role in determining attractiveness, Penton-Voak says. Men whose faces have some feminine softness are perceived as " kinder" men who may make better husbands and partners, he adds, while macho features may be associated with higher testosterone(睾丸素)levels and good genes. He cautions, however, that research hasn"t yet shown a link between a woman" s preferences in such tests and her actual behavior. Just because the studies of female preferences show changes across the menstrual cycle, as Pen-ton-Voak implies, does not mean that______.
微信支付 
支付宝支付