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Sugarless yoghurt (酸奶) could help beat bad breath, tooth decay and gum disease, say scientists. Japanese researchers found eating the yoghurt (62) levels of hydrogen sulphide (硫化氢) -- a major (63) of bad breath -- in 80% of volunteers. The (64) are active bacteria in yoghurt. Details were (65) at a meeting of the International Association for Dental Research. A(n) (66) of 24 volunteers who participated in the study were given strict instructions (67) oral health, diet and medicine taking. They spent two weeks (68) yoghurts and similar foods, like cheese. Researchers then (39) bacteria levels and odor-causing compounds, (70) hydrogen-sulphide. The volunteers then ate 90 grams of yoghurt a day for six weeks. At the end of the study, researchers took (71) again. They found hydrogen sulphide levels (72) in 80% of participants. Dr. Nigel Carter, chief executive of the British Dental Health Foundation, said, "The foundation has long been (73) people’s attention to sugar-free yoghurts as a healthy snack, so it is pleasing to hear that it may have oral health benefits we were previously (74) of." "Although this research is still in the early stages there is no (75) that sugar-free yoghurts provide a much healthier (76) to sweets and chocolate, and we would encourage snackers to (77) them into their diet." (78) , Dr. Carter stressed that the best way to beat bad breath was by (79) a good oral health routine. This involves brushing twice-a-day with fluoride (氟化物) toothpaste, cutting (80) on the frequency of sugary snacks and drinks and visiting a dentist (81) .
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For many years, people believed that the brain, like the body, rested during sleep. After all, we are rendered unconscious by sleep. Perhaps, it was thought, the brain just needs to stop thinking for a few hours every day. Wrong. During sleep, our brain -- the organ that directs us to sleep -- is itself extraordinarily active. And much of that activity helps the brain to learn, to remember and to make connections. It wasn’t so long ago that the regretful joke in research circles was that everyone knew sleep had something to do with memory -- except for the people who study sleep and the people who study memory. Then, in 1994, Israeli researchers reported that the average performance for a group of people on a memory test improved when the test was repeated after a break of many hours -- during which some subjects slept and others did not. In 2000, a Harvard team demonstrated that this improvement occurred only during sleep. There are several different types of memory -- including declarative (fact-based information), episodic (events from your life) and procedural (how to do something) -- and researchers have designed ways to test each of them. In almost every case, whether the test involves remembering pairs of words, tapping numbered keys in a certain order or figuring out the rules in a weather- prediction game, "sleeping on it" after first learning the task improves performance. It’s as if our brains squeeze in some extra practice time while we’re asleep. This isn’t to say that we can’t form memories when we’re awake. If someone tells you his name, you don’t need to fall asleep to remember it. But sleep will make it more likely that you do. Sleep-deprivation experiments have shown that a tired brain has a difficult time capturing memories of all sorts. Interestingly, sleep deprivation is more likely to cause us to forget information associated with positive emotion than information linked to negative emotion. This could explain, at least in part, why sleep deprivation can trigger depression in some people: memories stained with negative emotions are more likely than positive ones to "stick" in the sleep-deprived brain. Sleep also seems to be the time when the brain’s two memory systems -- the hippocampus (海马体) and the neocortex (新皮质) -- "talk" with one other. Experiences that become memories are laid down first in the hippocampus, eliminating whatever is underneath. If a memory is to be retained, it must be shipped from the hippocampus to a place where it will endure -- the neocortex, the wrinkled outer layer of the brain where higher thinking takes place. Unlike the hippocampus, the neocortex is a master at weaving the old with the new. And partly because it keeps incoming information at bay, sleep is the best time for the "undistracted" hippocampus to shuttle memories to the neocortex, and for the neocortex to link them to related memories. What do we know about the brain from the first paragraph
Questions 19 to 22 are based on the conversation you have just heard.
患者因失眠睡前服用苯巴比妥钠100mg，第二天上午呈现宿醉现象，这属于
The curse of jet lag has struck most international travelers at one time or another -- and anyone lucky enough to have avoided it will surely have suffered the equally unpleasant sleep-deprivation involved in an early-morning start. Nor, as shift workers know too, is it possible to escape by going to bed earlier the previous evening, and thus putting sleep in the bank. Sleepiness is controlled by the body’s internal biological clock, so an earlier bedtime just means several wakeful hours staring in frustration at a darkened ceiling. For years, some travelers and shift workers have sworn by melatonin (褪黑素). This is a hormone that regulates the biological clock. It is made in the brain by a structure called the pineal gland (松果体), as darkness sets in after sunset. Light is the one that keeps the biological clock in the same pace with solar time. The clock then tells the brain when to go to sleep. The theory of those who use melatonin is that an external dose of it can reset the clock, and thus cause the "go to sleep" signal to be sent at a more convenient moment~ Melatonin can also increase sleepiness during the day, when the pineal gland is not producing it. This has resulted in a growing, and often unregulated, market in melatonin-supplement tablets. The pharmaceutical industry’s response to this seems to be: "If you can’t beat them, join them." A paper in this week’s Lancet, by Shantha Rajaratnam of the Harvard Medical School and his colleagues, reports two trials, funded by drug companies, of tasimelteon, a substance that binds to the same receptors in the brain as melatonin does, and which it is expected will have a similar effect. In the course of these trials, more than 400 people had their bedtimes brought forward by five hours in controlled conditions. Half an hour before lights out, a quarter of them were given common drug, while the remaining three-quarters were given varying doses of tasimelteon. Dr. Rajaratnam and his colleagues report that the new drug let people fall asleep faster at the unnaturally early time, and also allowed them to sleep longer than those given the common one. When will melatonin be made in the brain according to the passage
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