单项选择
单项选择
五肽用二硝基氟苯(DNFB)分析，可得DNF-Ser，用胰蛋白酶水解得出三肽，其N端为Cys，而C端为Ala，那么该肽是
A:Ser-Lys-Cys-Phe-Ala B:Ala-Phe-Cys-Lys-Ser C:Ser-Cys-Lys-Phe-Ala D:Phe-Ala-Ser-Cys-Lys E:Lys-Cys-Phe-Ala-Ser
五肽用二硝基氟苯（DNFB）分析，可得DNP-Ser，用胰蛋白酶水解得出三肽，其N端为Cys，而C端为Ala，那么该肽是（）
A:Ser-Lys-Cys-Phe-Ala B:Ala-Phe-Cys-Lys-Ser C:Ser-Cys-Lys-Phe-Ala D:Phe-Ala-Ser-Cys-Lys E:Lys-Cys-Phe-Ala-Ser
Humans have never lacked for ways to get wasted. The natural world is full of soothing but addictive leaves and fruits and fungi, and for centuries, science has added them to the pharmacopoeia to relieve the pain of patients. In the past two decades, that’s been especially true. As the Joint Commission on the Accreditation of Healthcare Organizations developed new policies to treat pain more actively, approaching it not just as an unfortunate side effect of illness but as a fifth vital sign, along with temperature, heart rate, respirtory rate and blood pressure, a bounty of new opoids(鸦片类物)has rolled off Big Pharma’s production line.
There was fentanyl, synthetic opioid around since the 1960s that went into wide use as a treatment for cancer pain in the 1990s. That was followed by Oxycodone, a short-acting drug for more routine pain, and after thatcame Oxycontin, a 12-hour formulation of the same powerful pill. Finally came hydrocodone. The government considers hydrocodone a Schedule Ⅲ drug—one with a " moderate or low" risk of dependency, as opposed to Schedule Ⅱ’s, which carry a "severe" risk. Physicians must submit a written prescription for Schedule Ⅱ drugs ; for Schedule Ⅲ’s, they just phone the pharmacy. ( Schedule I substances are drugs like heroin that are never prescribed. ) For patients, that wealth of choices spelled danger.
The result has hardly been surprising. Since 1990, there has been a tenfold increase in prescriptions for opioids in the U. S. , according to the Centers for Disease Control and Prevention (CDCP). In 1990 there were barely 6, 000 deaths from accidental drug poisoning in the U. S. By 2007 that number had nearly quintupled, to 27, 658.
Health officials do not tease out which drug is responsible for every death, and it’s not always possible. "There may be lots of drugs on board, " says Cathy Barber, director of the Injury Control Research Center at the Harvard School of Public Health. "Is it the opioid that caused the death Or is it the combination of opioid, benzodiazepine and a cocktail the person had" Still, most experts agree that nothing but the exploding availability of opioids could be behind the exploding rate of death.
Despite such heavy death toil, the suivellance over these popular pills faces regulatory maze. In early 2009, the FDA announced that it was initiating a " risk-evaluation and mitigation strategy". The regulations the FDA is empowered to issue include requiring manufacturers to provide better information to patients and doctors, requiring doctors to meet certain educational criteria before writing opioid prescriptions and limiting the number of docs and pharmacies allowed to prescribe or dispense the drugs. "And with all that, "warns Dr. John Jenkins, director of the FDA’s Office of New Drugs, " we do still have to make sure patients have access to drugs they need. "Any regulations the FDA does impose won’t be announced until 2011 at the earliest and could take a year or more to roll out. That leaves millions of people continuing to fill prescriptions, tens of thousands per year dying and patients in genuine pain wondering when a needed medication will relieve their suffering—and when it could lead to something worse.
A:combined use of different drugs B:wrong prescription of doctors C:uncertain resource D:easy access to opoids
In spite of all stories of prosperity in the United States, not only does poverty exist there, but crimes of various types have been increasing at alarming rate. Most acts of violence were committed by young people . 57% of the criminals arrested in 1979 were youths below 25 of age.
Everyone agrees that crime is party a result of bad material conditions: poverty, lack of education, living without a settled home, being parentless, sufferings from other kings of misfortune, etc.
There are also other factors than material conditions which are responsible for the sharp increase of crime rate. In the first place, some state laws provide a death penalty but some protection. It is therefore possible and easy for anyone in the country to get a gun.
Finally, there has been too much shown on TV and too much reported in newspaper of all kinds of crimes-the details of which are so accurately described that even children know how to duplicate what they have seen or read. All there have resulted in a high frequency of crimes committed both by professional criminals and by nonprofessional ones in murder, drug smuggling, robbery, etc.
A:poverty B:being parentless C:lack of education D:easy access to guns
In spite of all stories of prosperity in the United States, not only does poverty exist there, but crimes of various types have been increasing at alarming rate. Most acts of violence were committed by young people . 57% of the criminals arrested in 1979 were youths below 25 of age.
Everyone agrees that crime is party a result of bad material conditions: poverty, lack of education, living without a settled home, being parentless, sufferings from other kings of misfortune, etc.
There are also other factors than material conditions which are responsible for the sharp increase of crime rate. In the first place, some state laws provide a death penalty but some protection. It is therefore possible and easy for anyone in the country to get a gun.
Finally, there has been too much shown on TV and too much reported in newspaper of all kinds of crimes-the details of which are so accurately described that even children know how to duplicate what they have seen or read. All there have resulted in a high frequency of crimes committed both by professional criminals and by nonprofessional ones in murder, drug smuggling, robbery, etc.
A:poverty B:being parentless C:lack of education D:easy access to guns
Password is a(n) (1) series of characters that enables a user (2) a file, computer or program. On multi - user systems, (3) user must enter his or her password (4) the computer will respond to commands. The password helps ensure that unauthorized users do not access the computer. In addition, data files and programs may require a password.
Ideally, the password should be something (5) could guess. In practice, most people choose a password that is easy to remember, such as their name or their initials. This is one reason it is relatively easy to break into most computer system.
A:obvious B:secret C:important D:easy
Password is a(n) (1) series of characters that enables a user (2) a file, computer or program. On multi - user systems, (3) user must enter his or her password (4) the computer will respond to commands. The password helps ensure that unauthorized users do not access the computer. In addition, data files and programs may require a password.
Ideally, the password should be something (5) could guess. In practice, most people choose a password that is easy to remember, such as their name or their initials. This is one reason it is relatively easy to break into most computer system.
A:access B:accessing C:accessed D:to access
