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Liebermann-Burchard反应是用于鉴别
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溶剂沉淀法中的水醇法主要用于沉淀的成分是
Keeping Cut Flowers1 While everybody enjoys fresh cut flowers around their house, few people know how to keep them for as long as possible. This may be done by keeping in mind a few simple facts.2 An important thing to remember about cut flowers is that they are sensitive to temperature. For example, studies have shown that cut carnations (康乃馨) retain their freshness eight times longer when kept at 12℃ than when kept at 26℃. Keeping freshly harvested flowers at the right temperatures is probably the most important aspect of flower care.3 Flowers are not intended by nature to live very long. Their biological purpose is simply to attract birds or insects, such as bees, for pollination (授粉). After that, they quickly dry up and die. The process by which flowers consume oxygen and produce carbon dioxide (二氧化碳), called respiration (呼吸), generates the energy the flower needs to give the flower its shape and color. The making of seeds also depends on this energy. While all living things respire, flowers have a high level of respiration. A result of all this respiration is heat, and for flowers the level of heat relative to the mass of the flower is very high. Respiration also brings about the eventual death of the flower. Thus the greater the level of respiration, the sooner the flower dies.4 How, then, to control the rate at which flowers die By controlling respiration. How is respiration con- trolled By controlling temperature. We know that respiration produces heat, but the reverse is also true. Thus by maintaining low temperatures, respiration is reduced and the cut flowers will age more slowly.5 Another vital factor in keeping cut flowers is the quality of the water in which they are placed. Flowers find it difficult to "drink" water that is dirty or otherwise polluted. Even when water looks and smells clean, it almost certainly contains harmful substances that can endanger the flowers. To rid the water of these unwanted substances, household chlorine bleach (含漂白剂) can be used in small quantities. It is recommended that 15 drops of chlorine bleach (at 4% solution) be added to each liter of water. The water and solution should also be replaced each day. Another important way to prolong the life of cut flowers is ______.
New U.S. Plan for Disease PreventionUrging Americans to 1 responsibility for their health, Health and Human Services Secretary Tommy Thompson 2 Tuesday launched a $15 million program to try to 3 communities to do more to prevent chronic diseases like heart disease, cancer and diabetes.The initiative highlights the cost of chronic diseases—the leading causes of death in the United States— and outlines ways that people can 4 them, including better diet and increased exercise."In the United States today, 7 of 10 deaths and the vast majority of 5 illness, disability and health care costs are 6 by chronic diseases," the Health and Human Services Department said in a statement.The causes are often 7 —smoking, poor eating habits and a lack of exercise."I am 8 that preventing disease by promoting better health is a smart policy choice for our future," Thompson told at a conference held to launch the initiative."Our current health care system is not structured to 9 with the escalating costs of treating diseases that are largely preventable through changes in our lifestyle choices."Thompson said heart disease and strokes will cost the country more than $351 billion in 2003."These leading causes of death for men and women are largely 10 , yet we as a nation are not taking the steps necessary for us to lead healthier, longer lives," he said.The $15 million is 11 to go to communities to promote prevention, pushing for changes as simple as building sidewalks to encourage people to walk more. 12 exercise such as walking can prevent and even 13 heart disease and diabetes, and prevent cancer and strokes.The money will also go to community organizations, clinics and nutritionists who are being encouraged to work together to educate people at 14 of diabetes about what they can do to prevent it and encourage more cancer screening.The American Cancer Society 15 that half of all cancers can be caught by screening, including Pap tests for cervical (子宫颈的) cancer, mammograms (乳房X射线照片) for breast cancer, colonoscopies (结肠镜检查), and prostate (前列腺的) checks.If such cancers were all caught by early screening, the group estimates that the survival rate for cancer would rise to 95 percent.
New U.S. Plan for Disease PreventionUrging Americans to 1 responsibility for their health, Health and Human Services Secretary Tommy Thompson 2 Tuesday launched a $15 million program to try to 3 communities to do more to prevent chronic diseases like heart disease, cancer and diabetes.The initiative highlights the cost of chronic diseases—the leading causes of death in the United States— and outlines ways that people can 4 them, including better diet and increased exercise."In the United States today, 7 of 10 deaths and the vast majority of 5 illness, disability and health care costs are 6 by chronic diseases," the Health and Human Services Department said in a statement.The causes are often 7 —smoking, poor eating habits and a lack of exercise."I am 8 that preventing disease by promoting better health is a smart policy choice for our future," Thompson told at a conference held to launch the initiative."Our current health care system is not structured to 9 with the escalating costs of treating diseases that are largely preventable through changes in our lifestyle choices."Thompson said heart disease and strokes will cost the country more than $351 billion in 2003."These leading causes of death for men and women are largely 10 , yet we as a nation are not taking the steps necessary for us to lead healthier, longer lives," he said.The $15 million is 11 to go to communities to promote prevention, pushing for changes as simple as building sidewalks to encourage people to walk more. 12 exercise such as walking can prevent and even 13 heart disease and diabetes, and prevent cancer and strokes.The money will also go to community organizations, clinics and nutritionists who are being encouraged to work together to educate people at 14 of diabetes about what they can do to prevent it and encourage more cancer screening.The American Cancer Society 15 that half of all cancers can be caught by screening, including Pap tests for cervical (子宫颈的) cancer, mammograms (乳房X射线照片) for breast cancer, colonoscopies (结肠镜检查), and prostate (前列腺的) checks.If such cancers were all caught by early screening, the group estimates that the survival rate for cancer would rise to 95 percent.
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