关键词：雨花雅思词汇备考,雅思 雅思词汇 雨花雅思词汇备考,雅思
雨花雅思词汇备考,雅思如何备课雅思，雅思单项辅导，专业雅思培训机构，长沙环球雅思培训经典语录：偷偷地把自己当成老板或主管——逐渐培养自己当老板或主管的能力。。
长沙环球雅思培训课程：
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雅思基础（保
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雅思精品（6分）班
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6.5分高分班(选修外教口语)
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雅思mini精英班
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雅思“6分无限时”班
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高中生雅思“6段式”
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6.5分高分(选修词汇或语法)
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“4+1”式预备a套餐班
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“4+1”式预备b套餐班
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雅思狂人写作系列课程
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海外求生口语班
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雅思全真语法课
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雅思外教口语集训课程
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“四大名教”精讲点题班
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r1（高分级） r2(强化级)课程
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雅思语法提高班
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雨花雅思词汇备考,雅思
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r3(预备级+强化级)课程
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雅思全真词汇班
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雅思强化（6分）班
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长沙雅思培训，长沙出国语言培训，雅思辅导班、雅思备考，长沙环球雅思经典格言：认真努力的人，命运从来不会辜负他！雨花雅思词汇备考,雅思。
雨花雅思词汇备考,雅思雅思模拟试题在雅思备考过程中所起的作用不可小觑，通过模拟练习题，我们可以很直接地了解到自己的备考状况，从而可以更有针对性地进行之后的复习。希望以下内容能够对大家的雅思备考有所帮助!
Why did a promising heart drug fail?
Doomed drug highlights complications of meddling with cholesterol.
1. The failure of a high-profile cholesterol drug has thrown a spotlight on the complicated machinery that regulates cholesterol levels. But many researchers remain confident that drugs to boost levels of 'good' cholesterol are still one of the most promising means to combat spiralling heart disease.
2. Drug company Pfizer announced on 2 December that it was cancelling all clinical trials of torcetrapib, a drug designed to raise heart-protective high-density lipoproteins (HDLs). In a trial of 15000 patients, a safety board found that more people died or suffered cardiovascular problems after taking the drug plus a cholesterol-lowering statin than those in a control group who took the statin alone.
3. The news came as a kick in the teeth to many cardiologists because earlier tests in animals and people suggested it would lower rates of cardiovascular disease. "There have been no red flags to my knowledge," says John Chapman, a specialist in lipoproteins and atherosclerosis at the National Institute for Health and Medical Research (INSERM) in Paris who has also studied torcetrapib. "This cancellation came as a complete shock."
4. Torcetrapib is one of the most advanced of a new breed of drugs designed to raise levels of HDLs, which ferry cholesterol out of artery-clogging plaques to the liver for removal from the body. Specifically, torcetrapib blocks a protein called cholesterol ester transfer protein (CETP), which normally transfers the cholesterol from high-density lipoproteins to low density, plaque-promoting ones. Statins, in contrast, mainly work by lowering the 'bad' low-density lipoproteins.
Under pressure
5. Researchers are now trying to work out why and how the drug backfired, something that will not become clear until the clinical details are released by Pfizer. One hint lies in evidence from earlier trials that it slightly raises blood pressure in some patients. It was thought that this mild problem would be offset by the heart benefits of the drug. But it is possible that it actually proved fatal in some patients who already suffered high blood pressure. If blood pressure is the explanation, it would actually be good news for drug developers because it suggests that the problems are specific to this compound. Other prototype drugs that are being developed to block CETP work in a slightly different way and might not suffer the same downfall.
6. But it is also possible that the whole idea of blocking CETP is flawed, says Moti Kashyap, who directs atherosclerosis research at the VA Medical Center in Long Beach, California. When HDLs excrete cholesterol in the liver, they actually rely on LDLs for part of this process. So inhibiting CETP, which prevents the transfer of cholesterol from HDL to LDL, might actually cause an abnormal and irreversible accumulation of cholesterol in the body. "You're blocking a physiologic mechanism to eliminate cholesterol and effectively constipating the pathway," says Kashyap.
Going up
7. Most researchers remain confident that elevating high density lipoproteins levels by one means or another is one of the best routes for helping heart disease patients. But HDLs are complex and not entirely understood. One approved drug, called niacin, is known to both raise HDL and reduce cardiovascular risk but also causes an unpleasant sensation of heat and tingling. Researchers are exploring whether they can bypass this side effect and whether niacin can lower disease risk more than statins alone. Scientists are also working on several other means to bump up high-density lipoproteins by, for example, introducing synthetic HDLs. "The only thing we know is dead in the water is torcetrapib, not the whole idea of raising HDL," says Michael Miller, director of preventive cardiology at the University of Maryland Medical Center, Baltimore.
(613 words nature)雨花雅思词汇备考,雅思长沙雅思培训，长沙出国语言培训，雅思辅导班、雅思备考，长沙环球雅思经典格言：最美的不是成功的那一刻，而是事后回想奋斗过程中的艰辛!。
雅思考试备考课程 25年培训经验，长沙雅思培训，长沙出国语言培训，雅思辅导班、雅思备考，长沙环球雅思经典格言：如切如磋，如琢如磨。——《诗经·卫风·湛奥》雨花雅思词汇备考,雅思。
