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Sample records for drugs methods problems

  1. Is the Drug Problem Soluble?

    ERIC Educational Resources Information Center

    Jonas, Steven

    1989-01-01

    Concludes that the principle drug problems in the United States arise from the use of cigarette tobacco and alcoholic beverages. Identifies a drug culture as the persistent force in society that promotes drug use. Points out that the influence of the primary drug industries inhibit attempts to deal effectively with drug problems. (KO)

  2. The Drug Problem.

    ERIC Educational Resources Information Center

    Gose, Ben

    1995-01-01

    Drug law violations have risen sharply on college campuses, but officials disagree on the reason. Some students feel administrators are invading their privacy. The trend is attributed to several factors, including changes in how violations are counted, reduced tolerance of increased drug use by non-drug-using students, and more vigorous…

  3. Emerging drug problems in Asia

    PubMed Central

    Bart, Gavin

    2014-01-01

    This session, “Emerging Drug Problems in Asia,” focused on emerging drug problems in Asia. Dr. Juana Tomás-Rosselló discussed “East and Southeast Asia: Emerging Drug Problems and Response” and Dr. Wei J. Chen discussed “Ketamine Use among Regular Tobacco and Alcohol Users as Revealed by Respondent Driven Sampling in Taipei: Prevalence, Expectancy, and Users' Risky Decision Making.” PMID:25267884

  4. Preventing Alcohol-Related Problems on Campus: Methods for Assessing Student Use of Alcohol and Other Drugs. A Guide for Program Coordinators.

    ERIC Educational Resources Information Center

    DeJong, William; Wechsler, Henry

    Under the Drug-Free Schools and Campuses Act, institutions of higher education are required to review the effectiveness of their alcohol and drug prevention programs biannually. This guide offers a method for gathering and interpreting student survey data on alcohol-related problems based on the methodology of the College Alcohol Survey developed…

  5. Problems with drugs in Croatia.

    PubMed

    Vrhovac, B

    1997-01-01

    Croatia has 4.8 million inhabitants, 11,800 physicians, 2000 pharmacists, two now shareholding, pharmaceutical companies (about 6500 employees, total sales of about 350 million US dollars). There are a number of problems due to the war (GNP fell from 3800 to about 1500 US dollars), occupation of 25% of its territory, 0.5 million refugees and lack of resources (139 US dollars/capita for health, about 40 US dollars i.e. 30%!! for drugs)--about three times less than before the aggression. The drug situation is controlled with the help of: (1) donations (approximate value of 600 million US dollars since 1991 from Europe and US), (2) (essential) drug formularies--250 for outpatients, and 580 generic names for various levels of hospital use, (3) special efforts to purchase drugs of good quality at a reasonable price (a kind of tender), (4) control of prescribing (prescriptions, specialists referral) especially by GPs. A new Medicines Act is in preparation and about 1000 generic names are on the market. DRUG EDUCATION: Pharmaca: the Croatian journal of pharmacotherapy has been published since 1962, there are several Drug bulletins (one published since 1975); special chapters on clinical pharmacology in textbooks, translation of three editions of Laurence's textbook with special commentary and adaptation to local needs; ADR spontaneous and intensive monitoring (WHO programme) with a personal feedback to the reporters and regular articles on drug use in a number of periodicals. Data on drug consumption indicates that there is room for improvement of prescribing. There is an enthusiasm for 'vasoactive drugs'--after dipirydamole came oxpentifylline and antimicrobials are always overprescribed. All these problems will hopefully decrease when the war finally stops and when industry (especially tourism) starts being fruitful again. In any case the importance of teaching of pharmacotherapy at the under- and postgraduate level should be recognized. PMID:15073805

  6. Testing the effects of brief intervention in primary care for problem drug use in a randomized controlled trial: rationale, design, and methods

    PubMed Central

    2012-01-01

    Background A substantial body of research has established the effectiveness of brief interventions for problem alcohol use. Following these studies, national dissemination projects of screening, brief intervention (BI), and referral to treatment (SBIRT) for alcohol and drugs have been implemented on a widespread scale in multiple states despite little existing evidence for the impact of BI on drug use for non-treatment seekers. This article describes the design of a study testing the impact of SBIRT on individuals with drug problems, its contributions to the existing literature, and its potential to inform drug policy. Methods/design The study is a randomized controlled trial of an SBIRT intervention carried out in a primary care setting within a safety net system of care. Approximately 1,000 individuals presenting for scheduled medical care at one of seven designated primary care clinics who endorse problematic drug use when screened are randomized in a 1:1 ratio to BI versus enhanced care as usual (ECAU). Individuals in both groups are reassessed at 3, 6, 9, and 12 months after baseline. Self-reported drug use and other psychosocial measures collected at each data point are supplemented by urine analysis and public health-related data from administrative databases. Discussion This study will contribute to the existing literature by providing evidence for the impact of BI on problem drug use based on a broad range of measures including self-reported drug use, urine analysis, admission to drug abuse treatment, and changes in utilization and costs of health care services, arrests, and death with the intent of informing policy and program planning for problem drug use at the local, state, and national levels. Trial registration ClinicalTrials.gov NCT00877331 PMID:23237456

  7. Illicit Drug Use and Problem Gambling

    PubMed Central

    Wayne Skinner, W. J.; Matheson, Flora I.

    2013-01-01

    Problem gambling, substance use disorders, and their cooccurrence are serious public health concerns. We conducted a comprehensive review of the literature to understand the present state of the evidence on these coaddictions. Our main focus was illicit drug use rather than misuse of legal substances. The review covers issues related to gambling as a hidden problem in the illicit drug use community; prevalence, problem gambling, and substance use disorders as kindred afflictions; problem gambling as an addiction similar to illicit drug use; risk factors and problems associated with comorbidity, and gender issues. We end with some suggestions for future research. PMID:25938114

  8. Estimating the total mortality among problem drug users.

    PubMed

    Cruts, Guus; Buster, Marcel; Vicente, Julian; Deerenberg, Ingeborg; Van Laar, Margriet

    2008-01-01

    This paper's objective is to develop a method to estimate the total mortality among problem drug users. The total mortality is given by a base rate of mortality not related to drugs and the deaths that are directly and indirectly related to drugs. A fatal poisoning by drugs (overdose) is directly related to drugs, whereas a casualty due to a drug-related disease or a drug-related accident is indirectly related to drugs. As an example of a method to estimate the total mortality, the results from a cohort study among methadone patients in Amsterdam were projected on the whole population of problem drug users in The Netherlands. Due to differences between the problem drug users in Amsterdam and the rest of the country, adjustments were required. It was found that an initial estimation did not require adjustment for injection behavior and gender but did require adjustment for age and the percentage of HIV infection. In a first unadjusted estimation, the total number of deaths among problem drug users in The Netherlands in 2001 was estimated at 606 deaths. After adjustment for age, the estimated mortality decreased to 573 deaths, and after adjustment for HIV infection, this estimation again decreased to 479 deaths. From the ultimately estimated mortality, 11% was considered to be not related to drugs, 23% was attributed directly to drugs, and 66% was attributed indirectly to drugs. The number of direct deaths, as estimated by this method, falls in the same order of magnitude as the number extracted from the Causes of Death Statistics, when selecting cases according to the Drug-Related Deaths Standard as established by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA). Further cross-validation with other measures will be needed to assess the accuracy of the method, the limitations of which are discussed with respect to stipulating directions for future research. PMID:18393087

  9. Prescription drug abuse: problem, policies, and implications.

    PubMed

    Phillips, Janice

    2013-01-01

    This article provides an overview on prescription drug abuse and highlights a number of related legislative bills introduced during the 112th Congress in response to this growing epidemic. Prescription drug abuse has emerged as the nation's fastest growing drug problem. Although prescription drugs have been used effectively and appropriately for decades, deaths from prescription pain medicine in particular have reached epidemic proportions. Bills related to prescription drug abuse introduced during the 112th Congress focus on strengthening provider and consumer education, tracking and monitoring prescription drug abuse, improving data collection on drug overdose fatalities, combating fraud and abuse in Medicare and Medicaid programs, reclassifying drugs to make them more difficult to prescribe and obtain, and enforcing stricter penalties for individuals who operate scam pain clinics and sell pain pills illegitimately. This article underscores the importance of a multifaceted approach to combating prescription drug abuse and concludes with implications for nursing. PMID:23245611

  10. Social Problems of Drug Use and Drug Policies.

    ERIC Educational Resources Information Center

    Fort, Joel

    The social and legal policies that control or prevent the use of mind-altering drugs are the main cause of the social problems arising from their use. The existing policies are ineffective; the wrong drugs receive the most attention and laws are directed at the wrong phase of the cycle of promotion, distribution and use. The following reforms are…

  11. [Drug interactions with contraceptive methods].

    PubMed

    Simon, P; Hakkou, F; Warot, D

    1984-03-01

    3 possible types of drug interactions with contraceptives involve oral contraceptives (OCs), IUDs, and spermicides. The interaction of combined OCs with various drugs is frequently discussed in the literature, but the reported facts are sometimes contradictory. Case studies have indicated failure of OCs in patients taking ampicillin, but comparative studies using ampicillin and placebos have shown no difference in rates of estrogen, progestogens, follicle stimulating hormone, or luteinizing hormone in the 2 groups. Individual differences and predispositions among some women appear to play a role in drug interactions. The clinician should be wary of modifying accepted prescription practices too readily in the face of findings that may be explained by other as yet undisclosed factors. Interactions are difficult to establish, as are their mechanisms. They may perhaps be explained by the estrogen or progestogen components of the pills, the timing of the antibiotic dose, the duration of treatment and the dosage used, resistance of the intestinal flora, self-medication, or other factors. The drug troleandomycin is a special case; it appears to favor the already existing tendency of OCs to provoke cholestatic jaundice. A table of drug interactions with OCs can be divided into 2 parts, those that have been confirmed and whose mechanisms of action are known, including antiepileptics such as phenobarbital, butobarbital, phenytoin, and primidone, and the drug rifampicin, which are enzyme inductors; and those that are suspected but as yet unconfirmed and whose mechanism of action is not established. The unconfirmed interactions involve a variety of effects in addition to pregnancy. It is not yet established whether enzyme inductors are a greater problem for users of low-dose pills, but the probable existence of individual variations in sensitivity causes problems in setting recommendations applicable to all patients. Interactions between progestogen-only OCs and other drugs

  12. Drug problem in southeast and southwest Asia.

    PubMed

    Kulsudjarit, Kongpetch

    2004-10-01

    In 2002, the drug problem in Southeast and Southwest Asia was serious, particularly in the production of opium and heroin in Afghanistan, Myanmar, and Laos, the three largest producers of illicit opium in the world. The increasing illicit manufacture of ATS, particularly methamphetamine, in Southeast Asia, mainly in China and Myanmar, was also a major concern. Some reports indicated that ephedrine, used for illicitly producing methamphetamine in Southeast Asia, is diverted and smuggled out of China and India, whereas caffeine, the adulterant used for producing methamphetamine tablets, is mainly smuggled into Myanmar through its border with Thailand. Seizure data showed a dramatic increase in trafficking in MDMA through Southeast Asia. In terms of the drug epidemic, in 2002, cannabis remained overall the main drug of abuse in all of the countries of Southeast and Southwest Asia. Opiates, mainly opium and heroin, were also the drugs of choice except in Thailand, where opiate abuse declined, but ATS was the main drug of abuse due to its low cost and availability. A significant increase in ATS abuse, amphetamine, methamphetamine, and MDMA among the youth who smoked, sniffed, and inhaled them was reported in Cambodia, China, Indonesia, Laos, Myanmar, the Philippines, and Thailand. Injecting drug use among opiate abusers has been identified as the prime cause of the rapid spread of HIV/AIDS in Southeast and Southwest Asia. PMID:15542748

  13. A Method for Solving Problems.

    ERIC Educational Resources Information Center

    Knoop, Robert

    1987-01-01

    Problem solving and decision making are considered to be keys to successful management. A normative method for problem solving is presented, suggesting that the analysis of the problem be structured along a five-step procedure: problem identification, analysis, decision alternatives, decision making, and decision implementation. Follow-up…

  14. Least bad solutions to the 'drugs problem'.

    PubMed

    Mugford, S

    1991-01-01

    This paper examines the current difficulties being faced in Australia by policy-makers attempting to regulate the non-medical use of illegal drugs, and it is suggested that the difficulties centre upon two aspects. First, existing prohibitions are unsuccessful, with use levels rising and, in some arenas (e.g. cocaine use in the USA), quite out of control. On the other hand, a move towards decriminalization or legalization is difficult because past propaganda has been so vehement that a change now apparently risks sending the wrong messages to young people. This dilemma means that there is no solution, including inertia, which is risk-free, nor is there one free of difficulties. It is thus relevant to think in terms of 'least bad' rather than 'best' when formulating a system to face these problems. The exploration of what this least bad solution might be begins with the examination of the prominent myths (such as 'the drug-free society', 'the evil pusher', 'the user as victim' and 'the young person as cultural dope') that hinder our reasoning. Secondly, by suggesting that, in a climate of increasing crime related to drugs, inability of prohibitions to control that use and escalating health risks attendant on use (including the AIDS problem), the central policy thrust must be harm reduction and damage minimization rather than illusory goals such as widespread abstinence. The paper concludes with a discussion of some relevant evidence on alternative options. PMID:16818303

  15. Revisiting sub-Saharan African countries' drug problems: health, social, economic costs, and drug control policy.

    PubMed

    Affinnih, Yahya H

    2002-02-01

    This article takes an international perspective on the drug problem in sub-Saharan Africa. This analysis borrows ideas from physical and economic geography as a heuristic device to conceptualize the global narcoscapes in which drug trafficking occurs. Both the legitimate and the illegal drug trade operate within the same global capitalist system and draw on the same technological innovations and business processes. Central to the paper's argument is evidence that sub-Saharan African countries are now integrated into the political economy of drug consumption due to the spill-over effect. These countries are now minor markets for "hard drugs" as the result of the activities of organizations and individual traffickers that use Africa as a staging point in their trade with Europe and the United States. As a result, sub-Saharan African countries have drug consumption problems that were essentially absent prior to 1980, along with associated health, social, and economic costs. The emerging drug problem has forced African countries to develop their own drug control policy. The sub-Saharan African countries mentioned below vary to some extent in the level of drug use and misuse problems: Burundi, Comoros, Djibouti, Eritrea, Ethiopia, Kenya, Madagascar, Malawi, Mauritius, Mozambique, Reunion, Rwanda, Seychelles, Somalia, Tanzania, Uganda, Zambia, Angola, Cameroon, Central African Republic, Chad, Congo, Congo (Zaire), Equatorial Guinea, Gabon, Sao Tome and Principe, Botswana, Lesotho, Namibia, South Africa, Swaziland, Benin, Burkina Faso, Cape Verde, Cote d'Ivoire, Gambia, Ghana, Guinea, Guinea Bissau, Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone, and Togo. As part of this effort, African countries are assessing the health, social, and economic costs of drug-use-related problems to pinpoint methods which are both effective and inexpensive, since their budgets for social programs are severely constrained. Many have progressed to the point of adopting anti-drug

  16. Computational Methods in Drug Discovery

    PubMed Central

    Sliwoski, Gregory; Kothiwale, Sandeepkumar; Meiler, Jens

    2014-01-01

    Computer-aided drug discovery/design methods have played a major role in the development of therapeutically important small molecules for over three decades. These methods are broadly classified as either structure-based or ligand-based methods. Structure-based methods are in principle analogous to high-throughput screening in that both target and ligand structure information is imperative. Structure-based approaches include ligand docking, pharmacophore, and ligand design methods. The article discusses theory behind the most important methods and recent successful applications. Ligand-based methods use only ligand information for predicting activity depending on its similarity/dissimilarity to previously known active ligands. We review widely used ligand-based methods such as ligand-based pharmacophores, molecular descriptors, and quantitative structure-activity relationships. In addition, important tools such as target/ligand data bases, homology modeling, ligand fingerprint methods, etc., necessary for successful implementation of various computer-aided drug discovery/design methods in a drug discovery campaign are discussed. Finally, computational methods for toxicity prediction and optimization for favorable physiologic properties are discussed with successful examples from literature. PMID:24381236

  17. Operational analysis for the drug detection problem

    NASA Astrophysics Data System (ADS)

    Hoopengardner, Roger L.; Smith, Michael C.

    1994-10-01

    New techniques and sensors to identify the molecular, chemical, or elemental structures unique to drugs are being developed under several national programs. However, the challenge faced by U.S. drug enforcement and Customs officials goes far beyond the simple technical capability to detect an illegal drug. Entry points into the U.S. include ports, border crossings, and airports where cargo ships, vehicles, and aircraft move huge volumes of freight. Current technology and personnel are able to physically inspect only a small fraction of the entering cargo containers. The complexities of how to best utilize new technology to aid the detection process and yet not adversely affect the processing of vehicles and time-sensitive cargo is the challenge faced by these officials. This paper describes an ARPA sponsored initiative to develop a simple, yet useful, method for examining the operational consequences of utilizing various procedures and technologies in combination to achieve an `acceptable' level of detection probability. Since Customs entry points into the U.S. vary from huge seaports to a one lane highway checkpoint between the U.S. and Canadian or Mexico border, no one system can possibly be right for all points. This approach can examine alternative concepts for using different techniques/systems for different types of entry points. Operational measures reported include the average time to process vehicles and containers, the average and maximum numbers in the system at any time, and the utilization of inspection teams. The method is implemented via a PC-based simulation written in GPSS-PC language. Input to the simulation model is (1) the individual detection probabilities and false positive rates for each detection technology or procedure, (2) the inspection time for each procedure, (3) the system configuration, and (4) the physical distance between inspection stations. The model offers on- line graphics to examine effects as the model runs.

  18. The Problem-Drinking Drug Addict. Services Research Report.

    ERIC Educational Resources Information Center

    Barr, Harriet L.; Cohen, Arie

    An increasingly important consideration in drug abuse policy and programming is the growing number of multiple substance abusers, i.e., problem-drinking drug addicts. A longitudinal study of two drug addict populations examined drug and alcohol usage, psychological variables, and criminal justice and employment indicators. Findings indicated that…

  19. Methods of assessment of antiepileptic drugs.

    PubMed Central

    Milligan, N; Richens, A

    1981-01-01

    Epilepsy is a symptom with protean manifestations and as such it is a difficult disease in which to carry out a therapeutic trial. The methods available to research workers for the assessment of new antiepileptic drugs are hampered by the fact that epilepsy is a fluctuant condition. Although it is a chronic disorder open to study using cross-over trials and within-patient comparisons, accurate assessment cannot be easily made at any one point in time. Research workers are therefore automatically placed at a time factor disadvantage and this is especially so for those searching for quick methods of evaluating new compounds. The need for a quick and reliable method of assessing a new antiepileptic drug has long been appreciated. This article will discuss the methods currently available and we will begin by considering the most commonly used method of assessment with particular reference to some of the problems involved in conducting a controlled clinical trial in epilepsy. PMID:7272157

  20. Influences of Motivational Contexts on Prescription Drug Misuse and Related Drug Problems

    PubMed Central

    Kelly, Brian C.; Rendina, H. Jonathon; Vuolo, Mike; Wells, Brooke E.; Parsons, Jeffrey T.

    2014-01-01

    Prescription drug misuse has emerged as a significant problem among young adults. While the effects of motivational contexts have been demonstrated for illicit drugs, the role of motivational contexts in prescription drug misuse remains understudied. Using data from 400 young adults recruited via time-space sampling, we examined the role of motivational contexts in the frequency of misuse of three prescription drug types as well as drug-related problems and symptoms of dependency. Both negative and positive motivations to use drugs are associated with increases in prescription drug misuse frequency. Only negative motivations are associated directly with drug problems and drug dependence, as well as indirectly via prescription pain killer misuse. Addressing positive and negative motivational contexts of prescription drug misuse may not only provide a means to reduce misuse and implement harm reduction measures, but may also inform the content of treatment plans for young adults with prescription drug misuse problems. PMID:25115134

  1. Influences of motivational contexts on prescription drug misuse and related drug problems.

    PubMed

    Kelly, Brian C; Rendina, H Jonathon; Vuolo, Mike; Wells, Brooke E; Parsons, Jeffrey T

    2015-01-01

    Prescription drug misuse has emerged as a significant problem among young adults. While the effects of motivational contexts have been demonstrated for illicit drugs, the role of motivational contexts in prescription drug misuse remains understudied. Using data from 400 young adults recruited via time-space sampling, we examined the role of motivational contexts in the frequency of misuse of three prescription drug types as well as drug-related problems and symptoms of dependency. Both negative and positive motivations to use drugs are associated with increases in prescription drug misuse frequency. Only negative motivations are associated directly with drug problems and drug dependence, as well as indirectly via prescription pain killer misuse. Addressing positive and negative motivational contexts of prescription drug misuse may not only provide a means to reduce misuse and implement harm reduction measures, but may also inform the content of treatment plans for young adults with prescription drug misuse problems. PMID:25115134

  2. Drug problems in China: recent trends, countermeasures, and challenges.

    PubMed

    Chen, Zhonglin; Huang, Kaicheng

    2007-02-01

    Drug crime in China is on an overall rising trend. Major drug crime cases are becoming more common, the types of drugs being trafficked are more diverse, and the smuggling and trafficking of drugs into the country and the smuggling of precursor chemicals out of the country have formed a bidirectional cycle. Drug crimes in China have also begun to show a conspicuous trend of internationalization. China's main countermeasures against drug crimes have been to pass new laws and regulations against drugs, to increase the efforts to eradicate cultivation, to establish and expand "drug-free communities" programs, and to strengthen international cooperation in antidrug campaigns. The existing problems demand prompt solutions, which include a shortage of funding and lack of accurate knowledge about prevalence of drug abuse and related data for scientifically studying the drug problems. PMID:17210659

  3. Party drugs: properties, prevalence, patterns, and problems.

    PubMed

    Maxwell, Jane Carlisle

    2005-01-01

    This review summarizes the latest literature on "party" or "club" drugs, defined as MDMA, GHB, ketamine, and Rohypnol, as published from 2002 to early 2005. Club drugs have been categorized as being used at raves and dance parties. The literature shows that each drug has different properties, users, and settings. Each drug has different adverse effects and requires different acute care protocols. Although these drugs were identified early, scientific information about them, including the toxicological tests to identify them, is still evolving. Increasing numbers of studies on the short- and long-term effects of these drugs on humans are being published, but because of limitations on research using human subjects, they may not always be as rigorous as desired and can be cited by drug users to discredit findings of harm. The lack of research-based information on these drugs has led to the emergence of web sites that may or may not provide accurate data. Evaluated chemical dependency treatment protocols using the latest research for each of these different drugs are needed. PMID:16048814

  4. Selective Prevention: Addressing Vulnerability to Problem Drug Use in Europe

    ERIC Educational Resources Information Center

    Burkhart, Gregor; Gyarmathy, V. Anna; Bo, Alessandra

    2011-01-01

    Following the 2003 publication of the European Union (EU) Council Recommendations and the 2005-2008 and 2009-2012 EU Drugs Action Plans, increasing attention has been given in EU member states' drug policies to populations that are vulnerable to problem drug use (PDU). Monitoring data reported to the EMCDDA by designated agencies from 30 countries…

  5. Drug Abuse and Politics: The Construction of a Social Problem.

    ERIC Educational Resources Information Center

    Jensen, Eric L.; And Others

    Relying on the social constructionist approach as advanced by Armand L. Mauss (1975), this paper analyzes the construction of a recent U.S. social problem, drug abuse. It is argued that the objective conditions of drug use alone cannot explain why drugs became an issue immediately prior to the 1986 Congressional elections. Explanations for the…

  6. Early Twentieth Century Responses to the Drug Problem.

    ERIC Educational Resources Information Center

    Pfennig, Dennis Joseph

    1991-01-01

    Describes early twentieth-century responses to the drug problem in the United States. Discusses pressure from the media and reformers to control the availability of drugs such as opium and cocaine that were widely available in over-the-counter medications. Focuses on New York State, which took the lead in enacting drug control legislation. (DK)

  7. [Drugs, a current problem. Alcohol dependency].

    PubMed

    Amigó Tadín, Montserrat

    2006-01-01

    Alcohol is a socially accepted drug which is commercialized in multiple products including wine, cognac, gin, beer, anisette, vermouth, rum, etc. and which can be consumed in small quantities without producing harmful effects on one's health; nonetheless, women are more susceptible to alcohol's damages and an abusive consumption of alcohol creates dependence and chronic diseases. Ten percent of those people who consume alcohol develop dependency and comprise the leading group of drug addicts in many countries. PMID:16493852

  8. Drug history taking and the identification of drug related problems in an accident and emergency department.

    PubMed Central

    Akwagyriam, I; Goodyer, L I; Harding, L; Khakoo, S; Millington, H

    1996-01-01

    OBJECTIVE--To determine the incidence of drug related problems that fail to be noted on casualty cards in patients subsequently admitted, and to compare medication histories as recorded by accident and emergency (A&E) senior house officers (SHOs) and a pharmacist. METHODS--An initial retrospective survey of 1459 acute inpatient admissions through A&E over a three month period was followed by a prospective study of 33 elderly patients. RESULTS--In the retrospective survey, 52 medication related problems were confirmed after examination of the medical records, of which only 16 were identified in A&E. In the prospective study, 125 currently prescribed items were identified by the pharmacist compared to 77 by A&E SHOs; 66% of the missed information was clinically relevant. Of 17 previous adverse drug reactions identified by the pharmacist only six were also recorded by the A&E officer. Only four over the counter medicines were identified by the A&E SHOs compared to 30 by the pharmacist. CONCLUSIONS--More accurate recording of drug history on casualty cards should be undertaken, particularly in respect of over the counter medication and the identification of drug related problems. PMID:8733649

  9. Drug laws and the 'derivative' problem.

    PubMed

    King, Leslie A; Ujváry, István; Brandt, Simon D

    2014-01-01

    The concept of a 'derivative' is used widely in chemistry, where its precise meaning depends on the circumstances. However, numerous examples of derivative also occur in domestic drugs legislation, some of which stem from the 1961 United Nations Single Convention on Narcotic Drugs. There is a commonly held view that only 'first-order' derivatives should be considered: substances that can be created from a parent structure in a single chemical reaction. In other words, 'derivatives of derivatives' are excluded. However, some substances related to ecgonine (e.g. 2-carbomethoxytropinone) are clearly convertible to cocaine, even though this may require more than one reaction step. It follows that 2-carbomethoxytropinone is a controlled drug, a situation that most chemists would regard as perverse. A more extreme example of the complexity of 'derivative' is shown by the conversion of thebaine to buprenorphine. Even though this requires six or more stages, the US Drug Enforcement Administration successfully argued in a 1986 case that for the purposes of the Controlled Substances Act, the number of steps required was irrelevant; buprenorphine was a derivative of thebaine. Because the term derivative is rarely defined in statutes, the legal status of some substances, such as 2-bromo-LSD, is uncertain. Although a number of definitions of derivative can be found in the chemical literature, no single definition is adequate to describe all situations where it occurs in legislation. Unless qualified, it is suggested that the term derivative should be avoided in any future legislation. PMID:23949903

  10. [An identification method for mineral drugs].

    PubMed

    Sun, B; Gong, Y

    1990-05-01

    This paper is a report on a method for chemical identification of 58 mineral drugs. Combined with the Chinese traditional identification, the method can differentiate the sham and genuine drugs in a few minutes. PMID:2275776

  11. Computer-Assisted Instruction; How to Solve Drug Formulation Problems.

    ERIC Educational Resources Information Center

    Mezei, Janos; And Others

    1990-01-01

    Computer simulation of drug formulation problems involves a database of pharmacological properties, chemical stability, and compatibility data on 20 active ingredients, physiological factors and requirements for parenteral solutions, and additives. The user gathers data from the database, formulates a stable and effective solution, and the drug is…

  12. Handbook for the Prevention and Control of Drug Problems.

    ERIC Educational Resources Information Center

    Parsippany - Troy Hills Board of Education, Parsippany, NJ.

    Guidelines for teachers relative to drug abuse are developed in this handbook offering special steps necessary in attempting to prevent and/or guide students with a drug problem. Stress is placed on helping each student individually understand the forces affecting him, and in helping him form the necessary positive attitudes to cope with each…

  13. Preventing Alcohol and Other Drug Problems through Drug Education. Policy Bulletin No. 3.

    ERIC Educational Resources Information Center

    Bailey, William J.

    Public schools have a responsibility to educate students about drug abuse, and states have a responsibility to assist schools in their efforts. Properly designed and implemented drug education programs are the most cost-effective means of preventing alcohol and other drug problems. Poorly designed and implemented programs, on the other hand, can…

  14. Problems of drug abuse and preventive measures in Poland.

    PubMed

    Tobolska-Rydz, H

    1986-01-01

    An increasing abuse of drugs emerged among young people in Poland at the end of the 1960s and the beginning of the 1970s. According to information provided by the Ministry of Health and Social Welfare, there are currently 35,000 drug abusers, but the actual number is estimated at approximately 200,000. The abuse of extract from poppy straw and the inhalation of volatile solvents, such as glue and paint remover, are the major drug abuse problems. Addicts prepare a decoction of poppy straw for injection, and morphine and heroin have been clandestinely manufactured in very elementary home-made laboratories. Recently, methamphetamine hydrochloride and lysergic acid diethylamide (LSD) have also been illicitly produced in such home-made laboratories. The increasing drug abuse problem has prompted the authorities to prepare new complementary drug control legislation, the Act on the Prevention of Narcotic Addiction, which was adopted on 31 January 1985. The Act provides for more effective preventive and treatment measures, as well as severe punishment for involvement in illicit drug trafficking. Treatment, rehabilitation and social reintegration of drug-dependent persons is provided on a voluntary basis, except for persons convicted of drug-related offences and for persons under 18 years of age, in which case treatment may be compulsory. PMID:3779183

  15. Drug-related problems among medical ward patients in Jimma university specialized hospital, Southwest Ethiopia

    PubMed Central

    Tigabu, Bereket Molla; Daba, Daniel; Habte, Belete

    2014-01-01

    Objective: The increasing number of available drugs and drug users, as well as more complex drug regimens led to more side effects and drug interactions and complicates follow-up. The objective of this study was to assess drug-related problems (DRPs) and associated factors in hospitalized patients. Methods: A hospital-based cross-sectional study design was employed. The study was conducted in Jimma University Specialized Hospital, Jimma, located in the south west of Addis Ababa. All patients who were admitted to the medical ward from February 2011 to March 2011 were included in the study. Data on sociodemographic variables, past medical history, drug history, current diagnosis, current medications, vital signs, and relevant laboratory data were collected using semi-structured questionnaire and data collection forms which were filling through patient interview and card review. Data were analyzed using SPSS version 16 for windows. Descriptive statistics, cross-tabs, Chi-square, and logistic regression were utilized. Findings: Out of 257 study participants, 189 (73.5%) had DRPs and a total of 316 DRPs were identified. From the six classes of DRPs studied, 103 (32.6%) cases related to untreated indication or need additional drug therapy, and 49 (15.5%) cases related to high medication dosage. Unnecessary drug therapy in 49 (15.5%) cases, low medication dosage in 44 (13.9%) cases, and ineffective drug therapy in 42 (13.3%) cases were the other classes of problems identified. Noncompliance in 31 (9.8%) cases was the least prevalent DRP. Independent factors which predicted the occurrence of DRPs in the study population were sex, age, polypharmacy, and clinically significant potential drug-drug interactions. The prevalence of DRPs was substantially high (73.5%). Conclusion: Drug-related problems are common among medical ward patients. Indication-related problems, untreated indication and unnecessary drug therapy were the most common types of DRPs among patients of our

  16. Community Development Strategies To Prevent Alcohol and Other Drug Problems.

    ERIC Educational Resources Information Center

    Strategy Alert, 1992

    1992-01-01

    How community-based groups are confronting and preventing alcohol and other drug problems and related crime in their communities is the focus of this publication. A wide range of approaches and strategies, used by 10 nonprofit, community-based organizations representative of urban and rural areas, are presented. Case studies describe two community…

  17. Community drug abuse agencies: an effective approach to the drug abuse problem.

    PubMed

    Cohen, M; Zitter, S; Savarese, R; Kern, J

    1976-01-01

    Community-based drug agencies were established as a means for confronting the drug abuse dilemma. However, due to the traditional guidelines that were followed in developing CBDA programs, the unique aspects of the problem were overlooked. This uniqueness relates to the ability of the drug culture to satisfy basic human needs. To be effective CBDA must be able to satisfy the same needs that clients previously met through participation in the drug culture. This article examines three areas of weakness which limit the effectiveness of CBDA: (1) fragment delivery of services; (2) perpetuation of minimal client involvement, commitment, and responsibility; and (3) motivational considerations of board members. The alternative family structure is described as an innovative CBDA approach that directly relates to the uniqueness of the drug abuse problem. PMID:10316884

  18. Potential and problems in ultrasound-responsive drug delivery systems

    PubMed Central

    Zhao, Ying-Zheng; Du, Li-Na; Lu, Cui-Tao; Jin, Yi-Guang; Ge, Shu-Ping

    2013-01-01

    Ultrasound is an important local stimulus for triggering drug release at the target tissue. Ultrasound-responsive drug delivery systems (URDDS) have become an important research focus in targeted therapy. URDDS include many different formulations, such as microbubbles, nanobubbles, nanodroplets, liposomes, emulsions, and micelles. Drugs that can be loaded into URDDS include small molecules, biomacromolecules, and inorganic substances. Fields of clinical application include anticancer therapy, treatment of ischemic myocardium, induction of an immune response, cartilage tissue engineering, transdermal drug delivery, treatment of Huntington’s disease, thrombolysis, and disruption of the blood–brain barrier. This review focuses on recent advances in URDDS, and discusses their formulations, clinical application, and problems, as well as a perspective on their potential use in the future. PMID:23637531

  19. Potential and problems in ultrasound-responsive drug delivery systems.

    PubMed

    Zhao, Ying-Zheng; Du, Li-Na; Lu, Cui-Tao; Jin, Yi-Guang; Ge, Shu-Ping

    2013-01-01

    Ultrasound is an important local stimulus for triggering drug release at the target tissue. Ultrasound-responsive drug delivery systems (URDDS) have become an important research focus in targeted therapy. URDDS include many different formulations, such as microbubbles, nanobubbles, nanodroplets, liposomes, emulsions, and micelles. Drugs that can be loaded into URDDS include small molecules, biomacromolecules, and inorganic substances. Fields of clinical application include anticancer therapy, treatment of ischemic myocardium, induction of an immune response, cartilage tissue engineering, transdermal drug delivery, treatment of Huntington's disease, thrombolysis, and disruption of the blood-brain barrier. This review focuses on recent advances in URDDS, and discusses their formulations, clinical application, and problems, as well as a perspective on their potential use in the future. PMID:23637531

  20. Automated method for study of drug metabolism

    NASA Technical Reports Server (NTRS)

    Furner, R. L.; Feller, D. D.

    1973-01-01

    Commercially available equipment can be modified to provide automated system for assaying drug metabolism by continuous flow-through. System includes steps and devices for mixing drug with enzyme and cofactor in the presence of pure oxygen, dialyzing resulting metabolite against buffer, and determining amount of metabolite by colorimetric method.

  1. Crystallization Methods for Preparation of Nanocrystals for Drug Delivery System.

    PubMed

    Gao, Yuan; Wang, Jingkang; Wang, Yongli; Yin, Qiuxiang; Glennon, Brian; Zhong, Jian; Ouyang, Jinbo; Huang, Xin; Hao, Hongxun

    2015-01-01

    Low water solubility of drug products causes delivery problems such as low bioavailability. The reduced particle size and increased surface area of nanocrystals lead to the increasing of the dissolution rate. The formulation of drug nanocrystals is a robust approach and has been widely applied to drug delivery system (DDS) due to the significant development of nanoscience and nanotechnology. It can be used to improve drug efficacy, provide targeted delivery and minimize side-effects. Crystallization is the main and efficient unit operation to produce nanocrystals. Both traditional crystallization methods such as reactive crystallization, anti-solvent crystallization and new crystallization methods such as supercritical fluid crystallization, high-gravity controlled precipitation can be used to produce nanocrystals. The current mini-review outlines the main crystallization methods addressed in literature. The advantages and disadvantages of each method were summarized and compared. PMID:26027573

  2. 49 CFR 40.205 - How are drug test problems corrected?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false How are drug test problems corrected? 40.205... WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Problems in Drug Tests § 40.205 How are drug test problems...), you must try to correct the problem promptly, if doing so is practicable. You may conduct...

  3. 49 CFR 40.205 - How are drug test problems corrected?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false How are drug test problems corrected? 40.205... WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Problems in Drug Tests § 40.205 How are drug test problems...), you must try to correct the problem promptly, if doing so is practicable. You may conduct...

  4. Regulatory Solutions to the Problem of High Generic Drug Costs

    PubMed Central

    Luo, Jing; Sarpatwari, Ameet; Kesselheim, Aaron S.

    2015-01-01

    Recent reports have highlighted dramatic price increases for several older generic drugs, including a number of essential products used to treat deadly infectious diseases. Although most of these medicines have been widely available at reasonable prices for decades, some manufacturers have seized on unique features of the pharmaceutical marketplace to seek substantial profits. In this Perspective, we examine limitations in current price regulation among public and private payors and consider several reforms that could address the problem of expensive generic drugs through improved competition. PMID:26693494

  5. Methods of Drug Delivery in Neurotrauma.

    PubMed

    Deng-Bryant, Ying; Readnower, Ryan; Leung, Lai Yee; Tortella, Frank; Shear, Deborah

    2016-01-01

    The central nervous system (CNS) is protected by blood-brain barrier (BBB) and blood-cerebrospinal-fluid (CSF) barrier that limit toxic agents and most molecules from penetrating the brain and spinal cord. However, these barriers also prevent most pharmaceuticals from entering into the CNS. Drug delivery to the CNS following neurotrauma is complicated. Although studies have shown BBB permeability increases in various TBI models, it remains as the key mitigating factor for delivering drugs into the CNS. The commonly used methods for drug delivery in preclinical neurotrauma studies include intraperitoneal, subcutaneous, intravenous, and intracerebroventricular delivery. It should be noted that for a drug to be successfully translated into the clinic, it needs to be administered preclinically as it would be anticipated to be administered to patients. And this likely leads to better dose selection of the drug, as well as recognition of any possible side effects, prior to transition into a clinical trial. Additionally, novel approach that is noninvasive and yet circumvents BBB, such as drug delivery through nerve pathways innervating the nasal passages, needs to be investigated in animal models, as it may provide a viable drug delivery method for patients who sustain mild CNS injury or require chronic treatments. Therefore, the focus of this chapter is to present rationales and methods for delivering drugs by IV infusion via the jugular vein, and intranasally in preclinical studies. PMID:27604714

  6. Annual Report on the State of the Drugs Problem in the European Union, 2000.

    ERIC Educational Resources Information Center

    European Monitoring Centre for Drugs and Drug Addiction, Lisbon (Portugal).

    This report presents an overview of the drug phenomenon in Europe at the start of the new millennium. The first chapter begins with a discussion of overall drug trends. Specifically, it examines trends in drug use and the consequences including multiple drug use; problem drug use and demand for treatment; drug-related deaths; drug-related…

  7. Inhibitors of topoisomerases as anticancer drugs: problems and prospects.

    PubMed

    Dwarakanath, B S; Khaitan, Divya; Mathur, Rohit

    2004-07-01

    DNA topoisomerases, which solve topological problems associated with various DNA transactions, are the targets of many therapeutic agents. Various topoisomerase inhibitors especially, topo-poisons, camptothecin (topo-I) and etoposide (topo-II) are some of the drugs that are used in the current treatment protocols, particularly for the treatment of leukemia (AML, ALL etc). However, tumor resistance, normal and non-specific tissue cytotoxicity are the limitations for successful development of these drugs as one of the primary therapeutic agents for the treatment of tumors in vitro. This brief review presents the current understanding about cytotoxicity development and outlines various approaches to overcome the limitations for enhancing the efficacy of topo-poison based anticancer drugs. PMID:15339028

  8. Problems in the regulatory policy of the drug market

    PubMed Central

    Miziara, Nathália Molleis; Coutinho, Diogo Rosenthal

    2015-01-01

    OBJECTIVE Analyze the implementation of drug price regulation policy by the Drug Market Regulation Chamber. METHODS This is an interview-based study, which was undertaken in 2012, using semi-structured questionnaires with social actors from the pharmaceutical market, the pharmaceuticals industry, consumers and the regulatory agency. In addition, drug prices were compiled based on surveys conducted in the state of Sao Paulo, at the point of sale, between February 2009 and May 2012. RESULTS The mean drug prices charged at the point of sale (pharmacies) were well below the maximum price to the consumer, compared with many drugs sold in Brazil. Between 2009 and 2012, 44 of the 129 prices, corresponding to 99 drugs listed in the database of compiled prices, showed a variation of more than 20.0% in the mean prices at the point of sale and the maximum price to the consumer. In addition, many laboratories have refused to apply the price adequacy coefficient in their sales to government agencies. CONCLUSIONS The regulation implemented by the pharmaceutical market regulator was unable to significantly control prices of marketed drugs, without succeeding to push them to levels lower than those determined by the pharmaceutical industry and failing, therefore, in its objective to promote pharmaceutical support for the public. It is necessary reconstruct the regulatory law to allow market prices to be reduced by the regulator as well as institutional strengthen this government body. PMID:26083945

  9. How the US Food and Drug Administration Can Solve the Prescription Drug Shortage Problem

    PubMed Central

    2013-01-01

    Drug shortages are threatening care quality and cost-containment efforts. I describe the pharmaceutical marketplace changes that have caused the problem, and propose new policies to solve it, through changing incentives for producers and purchasers. I propose a grading scheme for the Food and Drug Administration when it inspects manufacturing facilities in the United States and abroad. The inspections’ focus would change from closing unsafe plants to improving production process quality, reducing the likelihood that plants will be closed—the most frequent cause of drug shortages. PMID:23488502

  10. Spectral methods for time dependent problems

    NASA Technical Reports Server (NTRS)

    Tadmor, Eitan

    1990-01-01

    Spectral approximations are reviewed for time dependent problems. Some basic ingredients from the spectral Fourier and Chebyshev approximations theory are discussed. A brief survey was made of hyperbolic and parabolic time dependent problems which are dealt with by both the energy method and the related Fourier analysis. The ideas presented above are combined in the study of accuracy stability and convergence of the spectral Fourier approximation to time dependent problems.

  11. [The Swiss population and drug problems: perception of the problems and proposals for solutions].

    PubMed

    Leuthold, A; Cattaneo, M; Dubois-Arber, F

    1993-01-01

    The aim of this study is to investigate which problems in relation with drug abuse are considered to be the most important by the Swiss population and which measures do they support to reduce them. Base for this study are the results of a representative telephone survey realized in october 1991 with 1004 Swiss residents. People are mostly concerned with problems related to the danger for youth and those concerning public order but also with the human condition of addicts. Drug addicts are considered as people who have lost the sense of live, as sick but also as dangerous and less truthful. Supported are overall prevention, offers for therapies, the repression of trafficking and money-laundering but not of drug users as well as measures going in the direction of harm-minimisation (shooting rooms, medical prescription of drugs). Younger people, those with higher education and the german-speaking population have a more positive view of drug addicts and support measures in the sense of harm-minimisation. Elder people and the french-speaking population have a rather negative view of drug addicts and don't favour measures for harm-minimisation. PMID:8212910

  12. Random Walk Method for Potential Problems

    NASA Technical Reports Server (NTRS)

    Krishnamurthy, T.; Raju, I. S.

    2002-01-01

    A local Random Walk Method (RWM) for potential problems governed by Lapalace's and Paragon's equations is developed for two- and three-dimensional problems. The RWM is implemented and demonstrated in a multiprocessor parallel environment on a Beowulf cluster of computers. A speed gain of 16 is achieved as the number of processors is increased from 1 to 23.

  13. Information on actual medication use and drug-related problems in older patients: questionnaire or interview?

    PubMed

    Willeboordse, Floor; Grundeken, Lucienne H; van den Eijkel, Lisanne P; Schellevis, François G; Elders, Petra J M; Hugtenburg, Jacqueline G

    2016-04-01

    Background Information on medication use and drug-related problems is important in the preparation of clinical medication reviews. Critical information can only be provided by patients themselves, but interviewing patients is time-consuming. Alternatively, patient information could be obtained with a questionnaire. Objective In this study the agreement between patient information on medication use and drug-related problems in older patients obtained with a questionnaire was compared with information obtained during an interview. Setting General practice in The Netherlands. Method A questionnaire was developed to obtain information on actual medication use and drug-related problems. Two patient groups ≥65 years were selected based on general practitioner electronic medical records in nine practices; I. polypharmacy and II. ≥1 predefined general geriatric problems. Eligible patients were asked to complete the questionnaire and were interviewed afterwards. Main outcome measure Agreement on information on medication use and drug-related problems collected with the questionnaire and interview was calculated. Results Ninety-seven patients participated. Of all medications used, 87.6 % (95 % CI 84.7-90.5) was reported identically in the questionnaire and interview. Agreement for the complete medication list was found for 45.4 % (95 % CI 35.8-55.3) of the patients. On drug-related problem level, agreement between questionnaire and interview was 75 %. Agreement tended to be lower in vulnerable patients characterized by ≥4 chronic diseases, ≥10 medications used and low health literacy. Conclusion Information from a questionnaire showed reasonable agreement compared with interviewing. The patients reported more medications and drug-related problems in the interview than the questionnaire. Taking the limitations into account, a questionnaire seems a suitable tool for medication reviews that may replace an interview for most patients. PMID:26830412

  14. Collaborative Problem Solving Methods towards Critical Thinking

    ERIC Educational Resources Information Center

    Yin, Khoo Yin; Abdullah, Abdul Ghani Kanesan; Alazidiyeen, Naser Jamil

    2011-01-01

    This research attempts to examine the collaborative problem solving methods towards critical thinking based on economy (AE) and non economy (TE) in the SPM level among students in the lower sixth form. The quasi experiment method that uses the modal of 3X2 factorial is applied. 294 lower sixth form students from ten schools are distributed…

  15. The averaging method in applied problems

    NASA Astrophysics Data System (ADS)

    Grebenikov, E. A.

    1986-04-01

    The totality of methods, allowing to research complicated non-linear oscillating systems, named in the literature "averaging method" has been given. THe author is describing the constructive part of this method, or a concrete form and corresponding algorithms, on mathematical models, sufficiently general , but built on concrete problems. The style of the book is that the reader interested in the Technics and algorithms of the asymptotic theory of the ordinary differential equations, could solve individually such problems. For specialists in the area of applied mathematics and mechanics.

  16. Novel apparatus and method for drug reinforcement.

    PubMed

    Feduccia, Allison A; Duvauchelle, Christine L

    2010-01-01

    Animal models of reinforcement have proven to be useful for understanding the neurobiological mechanisms underlying drug addiction. Operant drug self-administration and conditioned place preference (CPP) procedures are expansively used in animal research to model various components of drug reinforcement, consumption, and addiction in humans. For this study, we used a novel approach to studying drug reinforcement in rats by combining traditional CPP and self-administration methodologies. We assembled an apparatus using two Med Associate operant chambers, sensory stimuli, and a Plexiglas-constructed neutral zone. These modifications allowed our experiments to encompass motivational aspects of drug intake through self-administration and drug-free assessment of drug/cue conditioning strength with the CPP test. In our experiments, rats self-administered cocaine (0.75 mg/kg/inj, i.v.) during either four (e.g., the "short-term") or eight (e.g., the "long-term") alternating-day sessions in an operant environment containing distinctive sensory cues (e.g., olfactory and visual). On the alternate days, in the other (differently-cued) operant environment, saline was available for self-infusion (0.1 ml, i.v.). Twenty-four hours after the last self-administration/cue-pairing session, a CPP test was conducted. Consistent with typical CPP findings, there was a significant preference for the chamber associated with cocaine self-administration. In addition, in animals undergoing the long-term experiment, a significant positive correlation between CPP magnitude and the number of cocaine-reinforced lever responses. In conclusion, this apparatus and approach is time and cost effective, can be used to examine a wide array of topics pertaining to drug abuse, and provides more flexibility in experimental design than CPP or self-administration methods alone. PMID:20811325

  17. An efficient method for inverse problems

    NASA Technical Reports Server (NTRS)

    Daripa, Prabir

    1987-01-01

    A new inverse method for aerodynamic design of subcritical airfoils is presented. The pressure distribution in this method can be prescribed in a natural way, i.e. as a function of arclength of the as yet unknown body. This inverse problem is shown to be mathematically equivalent to solving a single nonlinear boundary value problem subject to known Dirichlet data on the boundary. The solution to this problem determines the airfoil, the free stream Mach number M(sub x) and the upstream flow direction theta(sub x). The existence of a solution for any given pressure distribution is discussed. The method is easy to implement and extremely efficient. We present a series of results for which comparisons are made with the known airfoils.

  18. Hybrid natural element method for viscoelasticity problems

    NASA Astrophysics Data System (ADS)

    Zhou, Yan-Kai; Ma, Yong-Qi; Dong, Yi; Feng, Wei

    2015-01-01

    A hybrid natural element method (HNEM) for two-dimensional viscoelasticity problems under the creep condition is proposed. The natural neighbor interpolation is used as the test function, and the discrete equation system of the HNEM for viscoelasticity problems is obtained using the Hellinger-Reissner variational principle. In contrast to the natural element method (NEM), the HNEM can directly obtain the nodal stresses, which have higher precisions than those obtained using the moving least-square (MLS) approximation. Some numerical examples are given to demonstrate the validity and superiority of this HNEM. Project supported by the Natural Science Foundation of Shanghai, China (Grant No.13ZR1415900).

  19. 49 CFR 40.199 - What problems always cause a drug test to be cancelled?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false What problems always cause a drug test to be cancelled? 40.199 Section 40.199 Transportation Office of the Secretary of Transportation PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Problems in Drug Tests § 40.199 What problems...

  20. Prevalence of skin problems and leg ulceration in a sample of young injecting drug users

    PubMed Central

    2014-01-01

    Background Drug users suffer harm from the injecting process, and clinical services are reporting increasing numbers presenting with skin-related problems such as abscesses and leg ulcers. Skin breakdown can lead to long-term health problems and increased service costs and is often the first indication of serious systemic ill health. The extent of skin problems in injecting drug users has not previously been quantified empirically, and there is a dearth of robust topical literature. Where skin problems have been reported, this is often without clear definition and generic terms such as ‘soft tissue infection’ are used which lack specificity. The aim of this study was to identify the range and extent of skin problems including leg ulceration in a sample of injecting drug users. Definitions of skin problems were developed and applied to descriptions from drug users to improve rigour. Methods Data were collected in needle exchanges and methadone clinics across Glasgow, Scotland, from both current and former drug injectors using face-to-face interviews. Results Two hundred participants were recruited, of which 74% (n = 148) were males and 26% (n = 52) were females. The age range was 21–44 years (mean 35 years). Just under two thirds (64%, n = 127) were currently injecting or had injected within the last 6 months, and 36% (n = 73) had previously injected and had not injected for more than 6 months. Sixty per cent (n = 120) of the sample had experienced a skin problem, and the majority reported more than one problem. Most common were abscesses, lumps, track marks and leg ulcers. Fifteen per cent (n = 30) of all participants reported having had a leg ulcer. Conclusions This is an original empirical study which demonstrated unique findings of a high prevalence of skin disease (60%) and surprisingly high rates of leg ulceration (15%). Skin disease in injecting drug users is clearly widespread. Leg ulceration in particular is a chronic recurring

  1. [Effects of the new comprehensive system for designating illegal drug components on the abuse of designer drugs and future problems based on an online questionnaire].

    PubMed

    Morino, Taichi; Okazaki, Mitsuhiro; Toda, Takaki; Yokoyama, Takashi

    2015-12-01

    Recently, the abuse of designer drugs has become a social problem. Designer drugs are created by modifying part of the chemical structure of drugs that have already been categorized as illegal, thereby creating a different chemical compound in order to evade Pharmaceutical Affairs Law regulations. The new comprehensive system for designating illegal drug components has been in effect since March 2013, and many designer drugs can now be regulated. We conducted an online questionnaire survey of people with a history of designer drug use to elucidate the effects of the new system on the abuse of designer drugs and to identify potential future problems. Over half the subjects obtained designer drugs only before the new system was implemented. Awareness of the system was significantly lower among subjects who obtained designer drugs for the first time after its introduction than those who obtained the drugs only before its implementation. Due to the new system, all methods of acquiring designer drugs saw decreases in activity. However, the ratio of the acquisition of designer drugs via the Internet increased. Since over 50% of the subjects never obtained designer drugs after the new system was introduced, goals that aimed to make drug procurement more difficult were achieved. However, awareness of the new system among subjects who obtained designer drugs after the new system was introduced was significantly low. Therefore, fostering greater public awareness of the new system is necessary. The results of the questionnaire also suggested that acquiring designer drugs through the Internet has hardly been affected by the new system. We strongly hope that there will be a greater push to restrict the sale of designer drugs on the Internet in the near future. PMID:26975077

  2. Transport Test Problems for Hybrid Methods Development

    SciTech Connect

    Shaver, Mark W.; Miller, Erin A.; Wittman, Richard S.; McDonald, Benjamin S.

    2011-12-28

    This report presents 9 test problems to guide testing and development of hybrid calculations for the ADVANTG code at ORNL. These test cases can be used for comparing different types of radiation transport calculations, as well as for guiding the development of variance reduction methods. Cases are drawn primarily from existing or previous calculations with a preference for cases which include experimental data, or otherwise have results with a high level of confidence, are non-sensitive, and represent problem sets of interest to NA-22.

  3. Drug-related problems in medical wards of Tikur Anbessa specialized hospital, Ethiopia

    PubMed Central

    Ayalew, Mohammed Biset; Megersa, Teshome Nedi; Mengistu, Yewondwossen Taddese

    2015-01-01

    Objective: This study was aimed to determine the prevalence of drug-related problems (DRPs), identify the most common drugs, and drug classes involved in DRPs as well as associated factors with the occurrence of DRPs. Methods: A prospective cross-sectional study was conducted on 225 patients admitted to medical wards of Tikur Anbessa Specialized Hospital, Addis Ababa from March to June 2014. Data regarding patient characteristics, medications, diagnosis, length of hospitalization, investigation, and laboratory results were collected using data abstraction forms through review of patients’ medical card and medication charts. Identified DRPs were recorded and classified using DRP registration forms. The possible intervention measures for the identified DRPs were proposed and communicated to either the physician or the patient. Data were entered into Epi Info 7 and analyzed using SPSS version 21 (IBM Corp. Released 2012, Armonk, NY: IBM Corp). Findings: DRPs were found in 52% of study subjects. A drug-drug interaction (48% of all DRPs) was the most common DRP followed by adverse drug reaction (23%). Anti-infectives and gastrointestinal medicines were commonly involved in DRPs. Drugs with the highest drug risk ratio were gentamycin, warfarin, nifedipine, and cimetidine. The number of drugs taken by the patient per day is an important risk factor for DRPs. Conclusion: DRPs are common among medical ward patients. Polypharmacy has a significant association with the occurrence of DRP. Drugs such as gentamycin, warfarin, nifedipine, and cimetidine have the highest probability of causing DRP. So, patients who are taking either of these drugs or polypharmacy should be closely assessed for identification and timely correction of DRPs. PMID:26645029

  4. [A proposal for the prevention of ethical problems related to drug promotion: a national network for drug information].

    PubMed

    Civaner, Murat

    2008-01-01

    The promotional activities of pharmaceutical companies are becoming an increasingly hot topic among healthcare workers and the general public. There are many studies in the literature claiming that drug promotion may lead to ethical problems, irrational use of medication, and increased costs, as well as negative effects on the patient-physician relationship and the medical profession. When considering that healthcare workers generally acquire their knowledge from the pharmaceutical industry, the problems mentioned, which are indeed of paramount importance, and the need for effective and sustainable interventions are clearly revealed. Many kinds of interventions have been recommended by various authorities and studies in order to prevent the kinds of problems mentioned above, including training healthcare workers, publishing professional codes to serve as guidelines about which professional values should be protected and how to cope with different situations in relationship to the pharmaceutical industry, or applying the business ethics codes of the pharmaceutical companies. Studies that assessed the effectiveness of different interventions, however, revealed that educating healthcare workers about marketing methods and state regulations are the only effective interventions. In this article, after defining the problem, a proposed national network for drug information is to decrease the negative effects of drug promotion and to promote the rational choice of medicines is described. According to the World Health Organization, rational use of medicine is the most effective, safe, applicable/suitable, and, lastly, the most cost effective option. A national network that will gather drug information by compiling evidence-based knowledge and taking rational use of medicine measures into account should be established. It should transmit information to all healthcare workers in a fast, equal, up to date, easily accessible, and free way. The network should also support

  5. Multigrid Methods for Nonlinear Problems: An Overview

    SciTech Connect

    Henson, V E

    2002-12-23

    Since their early application to elliptic partial differential equations, multigrid methods have been applied successfully to a large and growing class of problems, from elasticity and computational fluid dynamics to geodetics and molecular structures. Classical multigrid begins with a two-grid process. First, iterative relaxation is applied, whose effect is to smooth the error. Then a coarse-grid correction is applied, in which the smooth error is determined on a coarser grid. This error is interpolated to the fine grid and used to correct the fine-grid approximation. Applying this method recursively to solve the coarse-grid problem leads to multigrid. The coarse-grid correction works because the residual equation is linear. But this is not the case for nonlinear problems, and different strategies must be employed. In this presentation we describe how to apply multigrid to nonlinear problems. There are two basic approaches. The first is to apply a linearization scheme, such as the Newton's method, and to employ multigrid for the solution of the Jacobian system in each iteration. The second is to apply multigrid directly to the nonlinear problem by employing the so-called Full Approximation Scheme (FAS). In FAS a nonlinear iteration is applied to smooth the error. The full equation is solved on the coarse grid, after which the coarse-grid error is extracted from the solution. This correction is then interpolated and applied to the fine grid approximation. We describe these methods in detail, and present numerical experiments that indicate the efficacy of them.

  6. The linear separability problem: some testing methods.

    PubMed

    Elizondo, D

    2006-03-01

    The notion of linear separability is used widely in machine learning research. Learning algorithms that use this concept to learn include neural networks (single layer perceptron and recursive deterministic perceptron), and kernel machines (support vector machines). This paper presents an overview of several of the methods for testing linear separability between two classes. The methods are divided into four groups: Those based on linear programming, those based on computational geometry, one based on neural networks, and one based on quadratic programming. The Fisher linear discriminant method is also presented. A section on the quantification of the complexity of classification problems is included. PMID:16566462

  7. The Commissioning and Provision of Advocacy for Problem Drug Users in English DATS: A Cross-Sectional Survey

    ERIC Educational Resources Information Center

    Cargill, Tamsin; Weaver, Tim D.; Patterson, Sue

    2012-01-01

    Aims: This study investigated the commissioning and delivery of advocacy for problem drug users. We aimed to quantify provision, describe the commissioning of advocacy services in Drug Action Teams (DATs) and to identify factors influencing advocacy provision. Methods: A cross-sectional survey of a randomly selected sample of 50 English DATs. The…

  8. Drug related problems in type 2 diabetes patients with hypertension: a cross-sectional retrospective study

    PubMed Central

    2013-01-01

    Background Type 2 diabetes (T2DM) patients with hypertension are at increased risk for experiencing drug-related problems (DRPs) since they often receive multiple medications and have multiple comorbidities. To date, there is a lack of studies conducted in T2DM patients with hypertension. This study aims to analyze the DRPs and identify factors affecting the DRPs in this patient population. Method This retrospective study involved T2DM patients with hypertension and was conducted at a tertiary hospital in Malaysia from January 2009 to December 2011. The assessment of DRPs was based on the Pharmaceutical Network Care Europe (PCNE) tool version 5.01. Results Two hundred patients with a total of 387 DRPs were identified. Among these patients, 90.5% had at least one DRP, averaging 1.9 ± 1.2 problems per patient. The most common DRPs encountered were insufficient awareness of health and diseases (26%), drug choice problems (23%), dosing problems (16%) and drug interactions (16%). The most implicated drugs were aspirin, clopidogrel, simvastatin, amlodipine and metformin. The six domains of DRPs found to have statistically significant associations were renal impairment, polypharmacy, cardiovascular disease, elderly status, and duration of hospital stay. Conclusions Early identification of the types and patterns of DRPs and the factors associated to them may enhance the prevention and management of DRPs in T2DM patients with hypertension. PMID:23289895

  9. College Students' Perceptions of Severity and Willingness to Seek Psychological Help For Drug and Alcohol Problems

    ERIC Educational Resources Information Center

    Lowinger, Robert Jay

    2012-01-01

    A sample of 201 college students were surveyed with respect to their perceptions of severity and willingness to seek psychological help for drug and alcohol problems. Results indicated that students perceive alcohol problems as significantly less serious than drug problems and are significantly less willing to seek help for alcohol problems. Males…

  10. The Problem of Confounding in Studies of the Effect of Maternal Drug Use on Pregnancy Outcome

    PubMed Central

    Källén, Bengt

    2012-01-01

    In most epidemilogical studies, the problem of confounding adds to the uncertainty in conclusions drawn. This is also true for studies on the effect of maternal drug use on birth defect risks. This paper describes various types of such confounders and discusses methods to identify and adjust for them. Such confounders can be found in maternal characteristics like age, parity, smoking, use of alcohol, and body mass index, subfertility, and previous pregnancies including previous birth of a malformed child, socioeconomy, race/ethnicity, or country of birth. Confounding by concomitant maternal drug use may occur. A geographical or seasonal confounding can exist. In rare instances, infant sex and multiple birth can appear as confounders. The most difficult problem to solve is often confounding by indication. The problem of confounding is less important for congenital malformations than for many other pregnancy outcomes. PMID:22190949

  11. Problem drinking and the dimension of involvement with drugs: a Guttman scalogram analysis of adolescent drug use.

    PubMed Central

    Donovan, J E; Jessor, R

    1983-01-01

    Analyses of data from two nationwide surveys of high school students, one carried out in 1974 and the other in 1978, suggest that problem drinking may be seen as yet another step along an underlying dimension of involvement with both licit and illicit drugs. The dimension of involvement with drugs consists of the following levels: nonuse of alcohol or illicit drugs; nonproblem use of alcohol; marijuana use; problem drinking; use of pills (amphetamines, barbiturates, hallucinogenic drugs); and the use of "hard drugs" such as cocaine or heroin. The dimension possesses excellent Guttman-scale properties in both national samples as well as in subsamples differing in gender and ethnic background. The ordering of the levels of involvement was confirmed by the ordering of the alcohol-drug involvement groups based on their mean scores on measures of psychosocial proneness for involvement in problem behavior. The excessive use of a licit drug, i.e., problem drinking, appears to indicate greater involvement in drug use than does the use of an illicit drug, marijuana. This finding points to the importance of distinguishing between use and problem use of drugs in efforts to understand adolescent drug involvement. PMID:6837819

  12. The Replica Method in Optimization Problems.

    NASA Astrophysics Data System (ADS)

    Liao, Wuwell W.

    In this thesis I discuss the application of the replica method in combinatorial optimization problems. In particular, I study certain graph-partitioning problems. One problem that I consider is the following. We are given a set of vertices V = (V_1,V_2,ldots V_{N}), with N even, and a set of edges E = {(V_{i},V _{j})i not= j}. Let each edge be connected with probability P. The bipartitioning problem is to divide V into two parts of equal size, in such a way as to minimize the number of edges N _{c} connecting these two parts. We are interested in the behavior of N_{c }/N, averaged over all possible configurations of edges in the limit N --> infty , as a function of the connectivity alpha = NP. When alpha is finite, the problem is shown to be similar, but not identical, to the mean field theory of a spin glass with finite connectivity. The replica-symmetric solution is derived. It is shown to be consistent with exact results for the infinite cluster obtained by P. Erdos.

  13. Drug Craving Terminology among Opiate Dependents; A Mixed Method Study

    PubMed Central

    Maarefvand, Masoomeh; Ghiasvand, Hamid Reza

    2013-01-01

    Objective Drug craving is defined as an urge to continue substance abuse. Drug dependents use different terms to express their subjective feeling of craving. This study was an attempt to generate an understanding of craving terminology among different groups of Persian speaking Iranian opiate dependents. Method Terms used for the meaning of drug craving were listed by 36 ex-opiate dependents in focus group discussion meetings in the first phase of the study. These terms were composed from Craving Terms Questionnaire. In the second phase, 120 subjects in 3 groups of opiate dependents and a group of Current Opiate Abusers rated usage frequency of each term in the questionnaire under a Twelve-Step Program, Methadone Maintenance, and Other Abstinence-based Programs. Results Eighty nine terms were categorized in stimulation and triggering, attention bias and obsession, decision making difficulty, information processing impairment, withdrawal induction, drug euphoric experience, mental urge, motor control problem, negative valancing and stigmatizing. Terms for the three categories of mental urge, attention bias and obsession and motor control problem were used more than others. Patients in Methadone Maintenance Treatment (MMT) group used different categories of craving terms in comparison to other groups. Abstinent cases reported higher total score for craving terms in comparison to other groups in Twelve-Step Program and other abstinence-based programs. Conclusion Each craving-related term is associated with some aspects of the multidimensional concept of craving. A drug-craving thesaurus could provide a better understanding of craving nature from a drug dependent point of view. There are differences among abstinence vs. maintenance based treated opiate dependents in using craving terms. Addiction therapists will benefit from accessing drug dependents’ lexicon to assess and create therapeutic alliance with their clients. PMID:24130609

  14. An inverse problem by boundary element method

    SciTech Connect

    Tran-Cong, T.; Nguyen-Thien, T.; Graham, A.L.

    1996-02-01

    Boundary Element Methods (BEM) have been established as useful and powerful tools in a wide range of engineering applications, e.g. Brebbia et al. In this paper, we report a particular three dimensional implementation of a direct boundary integral equation (BIE) formulation and its application to numerical simulations of practical polymer processing operations. In particular, we will focus on the application of the present boundary element technology to simulate an inverse problem in plastics processing.by extrusion. The task is to design profile extrusion dies for plastics. The problem is highly non-linear due to material viscoelastic behaviours as well as unknown free surface conditions. As an example, the technique is shown to be effective in obtaining the die profiles corresponding to a square viscoelastic extrudate under different processing conditions. To further illustrate the capability of the method, examples of other non-trivial extrudate profiles and processing conditions are also given.

  15. An alternative method on quadratic programming problems

    NASA Astrophysics Data System (ADS)

    Dasril, Y.; Mohd, I. B.; Mustaffa, I.; Aminuddin, MMM.

    2015-05-01

    In this paper we proposed an alternative approach to find the optimum solution of quadratic programming problems (QPP) in its original form without additional information such as slack variable, surplus variable or artificial variable as done in other favourite methods. This approached is based on the violated constraints by the unconstrained optimum. The optimal solution of QPP obtained by searching from initial point to another point alongside of feasible region.

  16. Similarity solution of a Stefan drug-release subdiffusion problem

    NASA Astrophysics Data System (ADS)

    Volpert, V. A.; Nepomnyashchy, A. A.

    2016-04-01

    Propagation of a gel/glass transition boundary in a polymer is considered in the context of drug release. Drug molecules are assumed to undergo subdiffusive motion in the gel and be quiescent in the glass region. Exact self-similar solutions for the drug concentration are constructed, and the amount of released drug is determined as a function of time.

  17. Identification of drug-related problems of elderly patients discharged from hospital

    PubMed Central

    Ahmad, Abeer; Mast, M Ruth; Nijpels, Giel; Elders, Petra JM; Dekker, Jacqueline M; Hugtenburg, Jacqueline G

    2014-01-01

    Background Drug-related problems (DRP) following hospital discharge are common among elderly patients using multiple drugs for the treatment of chronic diseases. The aim of this study was to investigate the occurrence of DRP in these patients using a specific tool for the identification of DRP by community pharmacists. Methods An observational study involving 340 patients aged over 60 years using at least five prescription drugs and discharged from hospital. The occurrence of DRP was assessed by means of an identification tool specifically developed for use by community pharmacists, including a semistructured patient interview and a checklist of common DRP. Results In total, 992 potential DRP were observed in the 340 patients (mean 2.9 ± 1.7). No drug prescribed but clear indication, an unnecessarily long duration of treatment, dose too low, and incorrect drug selection were the DRP most commonly observed. Ten percent of DRP occurring in 71 patients were drug–drug interactions. The number of DRP was related to the number of drugs prescribed. Frequently occurring DRP found using the patient interview were fear of side effects and no or insufficient knowledge of drug use. Medication of patients discharged from the pulmonary department and of those with type 2 diabetes was particularly associated with occurrence of DRP. Conclusion Following hospital discharge, DRP occur frequently among elderly patients using five or more drugs for the treatment of chronic disease. The number of DRP increased with the number of drugs used. An important task for community pharmacists is to identify, resolve, and prevent the occurrence of DRP among this patient group. Since DRP are associated with an increased risk of hospital readmissions, morbidity, and mortality, it is very important to develop intervention strategies to resolve and prevent DRP. PMID:24523581

  18. Protective Factors Can Mitigate Behavior Problems After Prenatal Cocaine and Other Drug Exposures

    PubMed Central

    Bann, Carla M.; Whitaker, Toni M.; Bauer, Charles R.; Shankaran, Seetha; LaGasse, Linda; Lester, Barry M.; Hammond, Jane; Higgins, Rosemary

    2012-01-01

    BACKGROUND: We determined the role of risk and protective factors on the trajectories of behavior problems associated with high prenatal cocaine exposure (PCE)/polydrug exposure. METHODS: The Maternal Lifestyle Study enrolled 1388 children with or without PCE, assessed through age 15 years. Because most women using cocaine during pregnancy also used other substances, we analyzed for the effects of 4 categories of prenatal drug exposure: high PCE/other drugs (OD), some PCE/OD, OD/no PCE, and no PCE/no OD. Risks and protective factors at individual, family, and community levels that may be associated with behavior outcomes were entered stepwise into latent growth curve models, then replaced by cumulative risk and protective indexes, and finally by a combination of levels of risk and protective indexes. Main outcome measures were the trajectories of externalizing, internalizing, total behavior, and attention problems scores from the Child Behavior Checklist (parent). RESULTS: A total of 1022 (73.6%) children had known outcomes. High PCE/OD significantly predicted externalizing, total, and attention problems when considering the balance between risk and protective indexes. Some PCE/OD predicted externalizing and attention problems. OD/no PCE also predicted behavior outcomes except for internalizing behavior. High level of protective factors was associated with declining trajectories of problem behavior scores over time, independent of drug exposure and risk index scores. CONCLUSIONS: High PCE/OD is a significant risk for behavior problems in adolescence; protective factors may attenuate its detrimental effects. Clinical practice and public health policies should consider enhancing protective factors while minimizing risks to improve outcomes of drug-exposed children. PMID:23184114

  19. A meshless method for unbounded acoustic problems.

    PubMed

    Shojaei, Arman; Boroomand, Bijan; Soleimanifar, Ehsan

    2016-05-01

    In this paper an effective meshless method is proposed to solve time-harmonic acoustic problems defined on unbounded domains. To this end, the near field is discretized by a set of nodes and the far field effect is taken into account by considering radiative boundary conditions. The approximation within the near field is performed using a set of local residual-free basis functions defined on a series of finite clouds. For considering the far field effect, a series of infinite clouds are defined on which another set of residual-free bases, satisfying the radiation conditions, are considered for the approximation. Validation of the results is performed through solving some acoustic problems. PMID:27250155

  20. Implicit Extrapolation Methods for Variable Coefficient Problems

    NASA Technical Reports Server (NTRS)

    Jung, M.; Ruede, U.

    1996-01-01

    Implicit extrapolation methods for the solution of partial differential equations are based on applying the extrapolation principle indirectly. Multigrid tau-extrapolation is a special case of this idea. In the context of multilevel finite element methods, an algorithm of this type can be used to raise the approximation order, even when the meshes are nonuniform or locally refined. Here previous results are generalized to the variable coefficient case and thus become applicable for nonlinear problems. The implicit extrapolation multigrid algorithm converges to the solution of a higher order finite element system. This is obtained without explicitly constructing higher order stiffness matrices but by applying extrapolation in a natural form within the algorithm. The algorithm requires only a small change of a basic low order multigrid method.

  1. Methods for the drug effectiveness review project.

    PubMed

    McDonagh, Marian S; Jonas, Daniel E; Gartlehner, Gerald; Little, Alison; Peterson, Kim; Carson, Susan; Gibson, Mark; Helfand, Mark

    2012-01-01

    The Drug Effectiveness Review Project was initiated in 2003 in response to dramatic increases in the cost of pharmaceuticals, which lessened the purchasing power of state Medicaid budgets. A collaborative group of state Medicaid agencies and other organizations formed to commission high-quality comparative effectiveness reviews to inform evidence-based decisions about drugs that would be available to Medicaid recipients. The Project is coordinated by the Center for Evidence-based Policy (CEbP) at Oregon Health & Science University (OHSU), and the systematic reviews are undertaken by the Evidence-based Practice Centers (EPCs) at OHSU and at the University of North Carolina. The reviews adhere to high standards for comparative effectiveness reviews. Because the investigators have direct, regular communication with policy-makers, the reports have direct impact on policy and decision-making, unlike many systematic reviews. The Project was an innovator of methods to involve stakeholders and continues to develop its methods in conducting reviews that are highly relevant to policy-makers. The methods used for selecting topics, developing key questions, searching, determining eligibility of studies, assessing study quality, conducting qualitative and quantitative syntheses, rating the strength of evidence, and summarizing findings are described. In addition, our on-going interactions with the policy-makers that use the reports are described. PMID:22970848

  2. Numerical methods for problems in computational aeroacoustics

    NASA Astrophysics Data System (ADS)

    Mead, Jodi Lorraine

    1998-12-01

    A goal of computational aeroacoustics is the accurate calculation of noise from a jet in the far field. This work concerns the numerical aspects of accurately calculating acoustic waves over large distances and long time. More specifically, the stability, efficiency, accuracy, dispersion and dissipation in spatial discretizations, time stepping schemes, and absorbing boundaries for the direct solution of wave propagation problems are determined. Efficient finite difference methods developed by Tam and Webb, which minimize dispersion and dissipation, are commonly used for the spatial and temporal discretization. Alternatively, high order pseudospectral methods can be made more efficient by using the grid transformation introduced by Kosloff and Tal-Ezer. Work in this dissertation confirms that the grid transformation introduced by Kosloff and Tal-Ezer is not spectrally accurate because, in the limit, the grid transformation forces zero derivatives at the boundaries. If a small number of grid points are used, it is shown that approximations with the Chebyshev pseudospectral method with the Kosloff and Tal-Ezer grid transformation are as accurate as with the Chebyshev pseudospectral method. This result is based on the analysis of the phase and amplitude errors of these methods, and their use for the solution of a benchmark problem in computational aeroacoustics. For the grid transformed Chebyshev method with a small number of grid points it is, however, more appropriate to compare its accuracy with that of high- order finite difference methods. This comparison, for an order of accuracy 10-3 for a benchmark problem in computational aeroacoustics, is performed for the grid transformed Chebyshev method and the fourth order finite difference method of Tam. Solutions with the finite difference method are as accurate. and the finite difference method is more efficient than, the Chebyshev pseudospectral method with the grid transformation. The efficiency of the Chebyshev

  3. Drug Abuse: Methadone Becomes the Solution and the Problem

    ERIC Educational Resources Information Center

    Bazell, Robert J.

    1973-01-01

    Methadone is used to divert heroin addicts from using stronger drugs. Rate of crimes committed by drug addicts has fallen considerably after putting them on methadone. Despite criticisms, methadone use seems to be encouraging for the future. (PS)

  4. Methods for Anticipating Problems with Electrical Wiring

    NASA Technical Reports Server (NTRS)

    Yost, William T. (Inventor); Cramer, K. Elliott (Inventor); Perey, Daniel F. (Inventor)

    2005-01-01

    Passive and active methods for anticipating problems with electrical wiring are provided. An insulative material in contact with an electrical conductor has at least one impurity that is impregnated in the insulative material and/or disposed thereon. An environment around the electrical conductor is monitored for the presence or the level of the impurity(ies) emanating from the insulative material in the form of a gaseous effluent. An alarm signal is generated when a predetermined level of the gaseous effluent is detected.

  5. Drug use, mental health and problems related to crime and violence: cross-sectional study1

    PubMed Central

    Claro, Heloísa Garcia; de Oliveira, Márcia Aparecida Ferreira; Bourdreaux, Janet Titus; Fernandes, Ivan Filipe de Almeida Lopes; Pinho, Paula Hayasi; Tarifa, Rosana Ribeiro

    2015-01-01

    Objective: to investigate the correlation between disorders related to the use of alcohol and other drugs and symptoms of mental disorders, problems related to crime and violence and to age and gender. Methods: cross-sectional descriptive study carried out with 128 users of a Psychosocial Care Center for Alcohol and other Drugs, in the city of São Paulo, interviewed by means of the instrument entitled Global Appraisal of Individual Needs - Short Screener. Univariate and multiple linear regression models were used to verify the correlation between the variables. Results: using univariate regression models, internalizing and externalizing symptoms and problems related to crime/violence proved significant and were included in the multiple model, in which only the internalizing symptoms and problems related to crime and violence remained significant. Conclusions: there is a correlation between the severity of problems related to alcohol use and severity of mental health symptoms and crime and violence in the study sample. The results emphasize the need for an interdisciplinary and intersectional character of attention to users of alcohol and other drugs, since they live in a socially vulnerable environment. PMID:26626010

  6. Youth Reporters Discuss "Problem" Drugs. Youth Reports Number 2.

    ERIC Educational Resources Information Center

    Herzog, Elizabeth; And Others

    This report on drugs is based on mail responses received from urban and suburban high school students enrolled in college preparatory courses. The questions asked of these students included: (1) how do teenagers feel about the use of the various kinds of drugs by people their age? (2) what makes some teenagers use such drugs? (3) what keeps some…

  7. Forging New Links. Police, Communities and the Drug Problem.

    ERIC Educational Resources Information Center

    Drug Strategies, Washington, DC.

    To examine new approaches to drug law enforcement, this report presents a number of police programs that emphasize prevention of drug use or disruption of drug transactions. The report is based on extensive interviews with police chiefs and officers, criminologists, criminal justice management consultants, U.S. Department of Justice personnel, and…

  8. Kinetics methods for clinical epidemiology problems.

    PubMed

    Corlan, Alexandru Dan; Ross, John

    2015-11-17

    Calculating the probability of each possible outcome for a patient at any time in the future is currently possible only in the simplest cases: short-term prediction in acute diseases of otherwise healthy persons. This problem is to some extent analogous to predicting the concentrations of species in a reactor when knowing initial concentrations and after examining reaction rates at the individual molecule level. The existing theoretical framework behind predicting contagion and the immediate outcome of acute diseases in previously healthy individuals is largely analogous to deterministic kinetics of chemical systems consisting of one or a few reactions. We show that current statistical models commonly used in chronic disease epidemiology correspond to simple stochastic treatment of single reaction systems. The general problem corresponds to stochastic kinetics of complex reaction systems. We attempt to formulate epidemiologic problems related to chronic diseases in chemical kinetics terms. We review methods that may be adapted for use in epidemiology. We show that some reactions cannot fit into the mass-action law paradigm and solutions to these systems would frequently exhibit an antiportfolio effect. We provide a complete example application of stochastic kinetics modeling for a deductive meta-analysis of two papers on atrial fibrillation incidence, prevalence, and mortality. PMID:26578757

  9. Kinetics methods for clinical epidemiology problems

    PubMed Central

    Corlan, Alexandru Dan; Ross, John

    2015-01-01

    Calculating the probability of each possible outcome for a patient at any time in the future is currently possible only in the simplest cases: short-term prediction in acute diseases of otherwise healthy persons. This problem is to some extent analogous to predicting the concentrations of species in a reactor when knowing initial concentrations and after examining reaction rates at the individual molecule level. The existing theoretical framework behind predicting contagion and the immediate outcome of acute diseases in previously healthy individuals is largely analogous to deterministic kinetics of chemical systems consisting of one or a few reactions. We show that current statistical models commonly used in chronic disease epidemiology correspond to simple stochastic treatment of single reaction systems. The general problem corresponds to stochastic kinetics of complex reaction systems. We attempt to formulate epidemiologic problems related to chronic diseases in chemical kinetics terms. We review methods that may be adapted for use in epidemiology. We show that some reactions cannot fit into the mass-action law paradigm and solutions to these systems would frequently exhibit an antiportfolio effect. We provide a complete example application of stochastic kinetics modeling for a deductive meta-analysis of two papers on atrial fibrillation incidence, prevalence, and mortality. PMID:26578757

  10. Quantitative Methods for Assessing Drug Synergism

    PubMed Central

    2011-01-01

    Two or more drugs that individually produce overtly similar effects will sometimes display greatly enhanced effects when given in combination. When the combined effect is greater than that predicted by their individual potencies, the combination is said to be synergistic. A synergistic interaction allows the use of lower doses of the combination constituents, a situation that may reduce adverse reactions. Drug combinations are quite common in the treatment of cancers, infections, pain, and many other diseases and situations. The determination of synergism is a quantitative pursuit that involves a rigorous demonstration that the combination effect is greater than that which is expected from the individual drug’s potencies. The basis of that demonstration is the concept of dose equivalence, which is discussed here and applied to an experimental design and data analysis known as isobolographic analysis. That method, and a related method of analysis that also uses dose equivalence, are presented in this brief review, which provides the mathematical basis for assessing synergy and an optimization strategy for determining the dose combination. PMID:22737266

  11. Hybrid intelligent optimization methods for engineering problems

    NASA Astrophysics Data System (ADS)

    Pehlivanoglu, Yasin Volkan

    The purpose of optimization is to obtain the best solution under certain conditions. There are numerous optimization methods because different problems need different solution methodologies; therefore, it is difficult to construct patterns. Also mathematical modeling of a natural phenomenon is almost based on differentials. Differential equations are constructed with relative increments among the factors related to yield. Therefore, the gradients of these increments are essential to search the yield space. However, the landscape of yield is not a simple one and mostly multi-modal. Another issue is differentiability. Engineering design problems are usually nonlinear and they sometimes exhibit discontinuous derivatives for the objective and constraint functions. Due to these difficulties, non-gradient-based algorithms have become more popular in recent decades. Genetic algorithms (GA) and particle swarm optimization (PSO) algorithms are popular, non-gradient based algorithms. Both are population-based search algorithms and have multiple points for initiation. A significant difference from a gradient-based method is the nature of the search methodologies. For example, randomness is essential for the search in GA or PSO. Hence, they are also called stochastic optimization methods. These algorithms are simple, robust, and have high fidelity. However, they suffer from similar defects, such as, premature convergence, less accuracy, or large computational time. The premature convergence is sometimes inevitable due to the lack of diversity. As the generations of particles or individuals in the population evolve, they may lose their diversity and become similar to each other. To overcome this issue, we studied the diversity concept in GA and PSO algorithms. Diversity is essential for a healthy search, and mutations are the basic operators to provide the necessary variety within a population. After having a close scrutiny of the diversity concept based on qualification and

  12. MIB Galerkin method for elliptic interface problems.

    PubMed

    Xia, Kelin; Zhan, Meng; Wei, Guo-Wei

    2014-12-15

    Material interfaces are omnipresent in the real-world structures and devices. Mathematical modeling of material interfaces often leads to elliptic partial differential equations (PDEs) with discontinuous coefficients and singular sources, which are commonly called elliptic interface problems. The development of high-order numerical schemes for elliptic interface problems has become a well defined field in applied and computational mathematics and attracted much attention in the past decades. Despite of significant advances, challenges remain in the construction of high-order schemes for nonsmooth interfaces, i.e., interfaces with geometric singularities, such as tips, cusps and sharp edges. The challenge of geometric singularities is amplified when they are associated with low solution regularities, e.g., tip-geometry effects in many fields. The present work introduces a matched interface and boundary (MIB) Galerkin method for solving two-dimensional (2D) elliptic PDEs with complex interfaces, geometric singularities and low solution regularities. The Cartesian grid based triangular elements are employed to avoid the time consuming mesh generation procedure. Consequently, the interface cuts through elements. To ensure the continuity of classic basis functions across the interface, two sets of overlapping elements, called MIB elements, are defined near the interface. As a result, differentiation can be computed near the interface as if there is no interface. Interpolation functions are constructed on MIB element spaces to smoothly extend function values across the interface. A set of lowest order interface jump conditions is enforced on the interface, which in turn, determines the interpolation functions. The performance of the proposed MIB Galerkin finite element method is validated by numerical experiments with a wide range of interface geometries, geometric singularities, low regularity solutions and grid resolutions. Extensive numerical studies confirm the

  13. Pattern of drug therapy problems and interventions in ambulatory patients receiving antiretroviral therapy in Nigeria

    PubMed Central

    Ojeh, Victor B.; Naima, Nasir; Abah, Isaac O.; Falang, Kakjing D.; Lucy, Ogwuche; London, Ibrahim; Dady, Christiana; Agaba, Patricia; Agbaji, Oche

    2015-01-01

    Objectives: We describe the frequency and types of drug therapy problems (DTPs), and interventions carried out to resolve them, among a cohort of HIV-infected patients on ART in Jos, Nigeria. Methods: A prospective pharmacists’ intervention study was conducted between January and August 2012 at the outpatient HIV clinic of the Jos University Teaching Hospital (JUTH). Pharmacists identified DTPs and made recommendations to resolve them. The main outcome measures were number of DTPs encountered, interventions proposed and acceptance rate of recommendations. Results: A total of 42,416 prescriptions were dispensed to 9339 patients during the eight months study. A total of 420 interventions (Intervention rate of 1 per 100 prescriptions) were made to resolve DTPs in 401 (4.3%) patients with a mean age of 41 (SD=10) years, and made up of 73% females. DTPs encountered were drug omission (n=89, 21.2%), unnecessary drug (n=55, 13.1%) and wrong drug indication (n=55, 13.1%). Recommendations offered included; Addition of another drug to the therapy (n=87, 20.7%), rectification of incomplete prescriptions (n=85, 20.2%), change of drug or dosage (n=67, 16.0%), and discontinuation of the offending drug (n=59, 14.0%). A total of 389 (93%) out of 420 of the recommendations were accepted. In all, 50.4% (212) of the problematic prescriptions were changed and dispensed, 22.2% (89) were clarified and dispensed, while wrong identities were corrected in 11.7% (49). However, 7.5% (30) prescriptions were dispensed as prescribed, 5.2% (21) were not dispensed, and 3% (12) were unresolved. Conclusion: Our findings suggest that pharmacists-initiated interventions can ameliorate DTPs in patients receiving ART given the high intervention acceptance rate recorded. The implication of this finding is that pharmacists with requisite training in HIV pharmacotherapy are an excellent resource in detecting and minimizing the effect of antiretroviral drug-related errors. PMID:26131046

  14. [Some problems due to the questionable indication for prescribing drugs].

    PubMed

    Mangeot, J P

    1997-01-01

    Once a diagnosis has been done, prescribers must take into account the indications and method of use of a product before prescribing it. The indications are given in the Product License and noted in the Summary of Product Characteristics. The "RMO" informs on what would be dangerous or useless to prescribe. From now on French prescribers will have in addition to take into account indications admitted to reimbursement by the Sécurité Sociale that might be different from the Product License indications. Various problems will follow: Necessity to establish standardised and classified indications to be used by all. Necessity that this standardisation be at a European level. The indications given in the Product License must be in strict accordance with what is in the dictionary. Necessity for the prescribers to be continuously kept up to date on this dictionary. Risk of differences between general practice and hospital where there is no such opposability. This will affect therapeutic research in France. These problems must be examined as a whole. PMID:9453174

  15. Developing natural product drugs: Supply problems and how they have been overcome.

    PubMed

    Newman, David J

    2016-06-01

    The development of natural product-derived drugs has some unique problems associated with the process, which can be best described as the "problem of supply". In this short review, four examples are given demonstrating how the "supply problem" was overcome using as examples the development of Picato® from a plant, Kyprolis® modified from a microbial metabolite, Halaven® a totally synthetic compound based on a marine sponge metabolite and Yondelis® isolated from a marine tunicate and now known to be from an as yet uncultured microbe in the tunicate. The methods used are described in each case and show how all scientific disciplines are necessary to succeed. All of these are antitumor agents and the time involved ranged from a low of 13years to greater than 29years from the initial identification of an active compound. PMID:26706239

  16. The Drug Problem and the Schools. ERIC Abstracts Series, Number Sixteen.

    ERIC Educational Resources Information Center

    American Association of School Administrators, Washington, DC.

    ERIC abstracts on the drug problem and the schools, announced in RIE through December 1970, are presented. The key terms used in compiling this collection are "drug abuse" and "drug addiction." The following information is presented for each document: Author, title, place of publication, publisher, publication date, number of pages, ERIC document…

  17. Program Administrator's Handbook. Strategies for Preventing Alcohol and Other Drug Problems. The College Series.

    ERIC Educational Resources Information Center

    CSR, Inc., Washington, DC.

    This handbook is for administrators of programs in higher education settings which deal with alcohol and other drug (AOD) related problems. Chapter 1, "Defining the Problem, Issues, and Trends" examines the problem from various perspectives and presents the latest statistics on the extent of AOD use on campuses, specific problems affecting…

  18. Problems of applicability of statistical methods in cosmology

    SciTech Connect

    Levin, S. F.

    2015-12-15

    The problems arising from the incorrect formulation of measuring problems of identification for cosmological models and violations of conditions of applicability of statistical methods are considered.

  19. Comprehensive Substance Abuse Services for Homeless Persons with Alcohol and Other Drug Problems.

    ERIC Educational Resources Information Center

    Kirby, Michael W., Jr.; Braucht, G. Nicholas

    Homeless people with alcohol and other drug problems present the traditional substance abuse services delivery provider with special challenges. This paper discusses the optimal designs of comprehensive treatment services for homeless persons with alcohol and other drug problems. Most importantly, the homeless must have immediate access to a safe…

  20. Interpersonal and Emotional Problem Solving among Narcotic Drug Abusers.

    ERIC Educational Resources Information Center

    Appel, Philip W.; Kaestner, Elisabeth

    1979-01-01

    Measured problem-solving abilities of narcotics abusers using the modified means-ends problem-solving procedure. Good subjects had more total relevent means (RMs) for solving problems, used more introspective and emotional RMs, and were better at RM recognition, but did not have more sufficient narratives than poor subjects. (Author/BEF)

  1. Drug-induced pancreatitis: A Potentially Serious and Underreported Problem.

    PubMed

    Kaufman, Michele B

    2013-06-01

    There have been many published reports of possible cases of drug-induced pancreatitis. In addition, some disease states and patient characteristics predispose particular populations to the development of this condition. Three case histories are presented. PMID:23946630

  2. [Somnolence of unknown origin--illness or drug problem?].

    PubMed

    Hug, B L

    2006-12-01

    A 64 year old female patient with previously known temporal lobe epilepsy (TLE) was admitted to the emergency department (ED) for further investigation of somnolence of unknown origin. Differential diagnosis remained puzzling after exclusion of an intracranial process and status epilepticus. Quantitative and qualitative fluctuations of consciousness are well known to take place in TLE as well as that these patients often are receiving several drugs for their illness. Drug history and measuring serum drug levels are helpful. Adverse Drug Events (ADE) are not rare in EDs: approximately 5% of ED patients are suffering an ADE and about 3% of patients admitted to hospitals are admitted because of an ADE. It is important to realize that three out of four ADEs are estimated to be preventable. PMID:17133299

  3. 49 CFR 40.203 - What problems cause a drug test to be cancelled unless they are corrected?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false What problems cause a drug test to be cancelled... PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Problems in Drug Tests § 40.203 What problems cause a drug test to be cancelled unless they are corrected? (a) As the MRO, when...

  4. 49 CFR 40.203 - What problems cause a drug test to be cancelled unless they are corrected?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false What problems cause a drug test to be cancelled... PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Problems in Drug Tests § 40.203 What problems cause a drug test to be cancelled unless they are corrected? (a) As the MRO, when...

  5. [Selected Readings for the Professional Working with Drug Related Problems.

    ERIC Educational Resources Information Center

    Wisconsin Univ., Madison.

    A bibliography of selected readings compiled at the University of Wisconsin for the National Drug Education Training Program. These selected readings include information on narcotics, amphetamines, mescaline, psilogybin, hallucinogens, LSD, barbiturates, alcohol, and other stimulants. The intended user of this bibliography is the professional…

  6. Drug Abuse in the Military: An Adolescent Misbehavior Problem.

    ERIC Educational Resources Information Center

    Beary, John F.; And Others

    1983-01-01

    Describes drug abuse in the military. Survey data of military personnel (N=15,268) revealed that single, enlisted males under age 25 were the population most at risk. Alcohol and cannabis were the most common substances of abuse. Some work impairment and dependence were reported but were not typical. (Author/JAC)

  7. Drug abuse problems in countries of the Andean subregion.

    PubMed

    Flores Agreda, R

    1986-01-01

    The scarcity of epidemiological data makes it difficult for an accurate and comprehensive assessment to be made of the drug abuse situation in countries of the Andean subregion. Available evidence, however, indicates that in Bolivia, Colombia and Peru prevalence and incidence rates of drug abuse, particularly of the abuse of basic cocaine paste, are relatively high. Studies indicate that in Bolivia 4-5 per cent of youth are habitual cocaine users and that in Colombia drug abuse was in 1984 the seventh leading cause of psychiatric morbidity. A survey in Peru shows that 37 per cent of secondary school students use drugs, while 27 per cent of the respondents used basic cocaine paste as their first drug. It appears that the abuse of basic cocaine paste has spread evenly across urban social classes. The illegal cultivation of the coca bush has drastically increased in countries of the Andean subregion. For example, it is estimated that more than 135,000 hectares of coca bush are cultivated in Peru, producing approximately 135,000 tons of coca leaves a year, while the amount needed for legitimate purposes in that country is estimated at 10,000 tons a year. In the same country, seizures of basic cocaine paste increased from 4,755 kg in 1980 to 7,168 kg in 1983, and of macerated coca leaf from 2,570 kg in 1979 to 27,822 kg in 1984. The demand for illicit cocaine has substantially increased in the world. It is estimated that the total amount of illicit cocaine consumed in the world was 33-45 tons in 1981 and 50-61 tons in 1983. PMID:3490890

  8. Alcohol and Other Drugs on Campus: The Scope of the Problem. Infofacts/Resources

    ERIC Educational Resources Information Center

    Kapner, Daniel Ari

    2008-01-01

    The most widespread health problem on college and university campuses in the United States is high-risk alcohol and other drug (AOD) use. Recent reports confirm that the nation's campuses continue to encounter significant consequences as a result of this problem. This "Infofacts/Resources" offers an overview of the problem and highlights effective…

  9. Discontinuous Mixed Covolume Methods for Parabolic Problems

    PubMed Central

    Zhu, Ailing

    2014-01-01

    We present the semidiscrete and the backward Euler fully discrete discontinuous mixed covolume schemes for parabolic problems on triangular meshes. We give the error analysis of the discontinuous mixed covolume schemes and obtain optimal order error estimates in discontinuous H(div) and first-order error estimate in L2. PMID:24983008

  10. Role of Molecular Dynamics and Related Methods in Drug Discovery.

    PubMed

    De Vivo, Marco; Masetti, Matteo; Bottegoni, Giovanni; Cavalli, Andrea

    2016-05-12

    Molecular dynamics (MD) and related methods are close to becoming routine computational tools for drug discovery. Their main advantage is in explicitly treating structural flexibility and entropic effects. This allows a more accurate estimate of the thermodynamics and kinetics associated with drug-target recognition and binding, as better algorithms and hardware architectures increase their use. Here, we review the theoretical background of MD and enhanced sampling methods, focusing on free-energy perturbation, metadynamics, steered MD, and other methods most consistently used to study drug-target binding. We discuss unbiased MD simulations that nowadays allow the observation of unsupervised ligand-target binding, assessing how these approaches help optimizing target affinity and drug residence time toward improved drug efficacy. Further issues discussed include allosteric modulation and the role of water molecules in ligand binding and optimization. We conclude by calling for more prospective studies to attest to these methods' utility in discovering novel drug candidates. PMID:26807648

  11. A Bright Future for Evolutionary Methods in Drug Design.

    PubMed

    Le, Tu C; Winkler, David A

    2015-08-01

    Most medicinal chemists understand that chemical space is extremely large, essentially infinite. Although high-throughput experimental methods allow exploration of drug-like space more rapidly, they are still insufficient to fully exploit the opportunities that such large chemical space offers. Evolutionary methods can synergistically blend automated synthesis and characterization methods with computational design to identify promising regions of chemical space more efficiently. We describe how evolutionary methods are implemented, and provide examples of published drug development research in which these methods have generated molecules with increased efficacy. We anticipate that evolutionary methods will play an important role in future drug discovery. PMID:26059362

  12. Network-Based Inference Methods for Drug Repositioning

    PubMed Central

    Zhang, Heng; Cao, Yiqin; Tang, Wenliang

    2015-01-01

    Mining potential drug-disease associations can speed up drug repositioning for pharmaceutical companies. Previous computational strategies focused on prior biological information for association inference. However, such information may not be comprehensively available and may contain errors. Different from previous research, two inference methods, ProbS and HeatS, were introduced in this paper to predict direct drug-disease associations based only on the basic network topology measure. Bipartite network topology was used to prioritize the potentially indicated diseases for a drug. Experimental results showed that both methods can receive reliable prediction performance and achieve AUC values of 0.9192 and 0.9079, respectively. Case studies on real drugs indicated that some of the strongly predicted associations were confirmed by results in the Comparative Toxicogenomics Database (CTD). Finally, a comprehensive prediction of drug-disease associations enables us to suggest many new drug indications for further studies. PMID:25969690

  13. Preparation of drug nanoparticles by emulsion evaporation method

    NASA Astrophysics Data System (ADS)

    Hoa, Le Thi Mai; Chi, Nguyen Tai; Triet, Nguyen Minh; Thanh Nhan, Le Ngoc; Mau Chien, Dang

    2009-09-01

    Polymeric drug nanoparticles were prepared by emulsion solvent evaporation method. In this study, prepared the polymeric drug nanoparticles consist of ketoprofen and Eudragit E 100. The morphology structure was investigated by scanning electron microscopy (SEM). The interactions between the drug and polymer were investigated by Fourier transform infrared spectroscopy (FTIR). The size distribution was measured by means of Dynamic Light Scattering. The nanoparticles have an average size of about 150 nm. The incorporation ability of drugs in the polymeric nanoparticles depended on the integration between polymer and drug as well as the glass transition temperature of the polymer.

  14. The Effect of a Problem-Solving Teaching Method on Student Problem-Solving Processes.

    ERIC Educational Resources Information Center

    Frank, David V.; Herron, J. Dudley

    A problem-solving method of teaching was used in the recitation sections of a freshmen chemistry course for science and engineering majors at Purdue University. The method was based on prior research which revealed that good problem solvers formed better representations and used heuristics more often than poor problem solvers. Consequently, the…

  15. Preconditioned Krylov subspace methods for eigenvalue problems

    SciTech Connect

    Wu, Kesheng; Saad, Y.; Stathopoulos, A.

    1996-12-31

    Lanczos algorithm is a commonly used method for finding a few extreme eigenvalues of symmetric matrices. It is effective if the wanted eigenvalues have large relative separations. If separations are small, several alternatives are often used, including the shift-invert Lanczos method, the preconditioned Lanczos method, and Davidson method. The shift-invert Lanczos method requires direct factorization of the matrix, which is often impractical if the matrix is large. In these cases preconditioned schemes are preferred. Many applications require solution of hundreds or thousands of eigenvalues of large sparse matrices, which pose serious challenges for both iterative eigenvalue solver and preconditioner. In this paper we will explore several preconditioned eigenvalue solvers and identify the ones suited for finding large number of eigenvalues. Methods discussed in this paper make up the core of a preconditioned eigenvalue toolkit under construction.

  16. Recovery from Problem Drug Use: What Can We Learn from the Dociologist Erving Goffman?

    ERIC Educational Resources Information Center

    Neale, Joanne; Nettleton, Sarah; Pickering, Lucy

    2011-01-01

    In this commentary, we critically review the contribution of the sociologist Erving Goffman (1922-1982) to understanding recovery from problem drug use. Previous research has indicated that drug users have a "spoiled identity" and must restore a "normal" or "unspoiled" identity in order to recover. This argument has been linked to Goffman's…

  17. Identifying and Preventing Health Problems among Young Drug-Misusing Offenders

    ERIC Educational Resources Information Center

    Bennett, Trevor; Holloway, Katy

    2008-01-01

    Purpose: The purpose of this paper is to identify the health problems and treatment needs of drug-misusing offenders and to draw out the implications of the findings for health education and prevention. Design/methodology/approach: This analysis is based on data collected as part of the New English and Welsh Arrestee Drug Abuse Monitoring…

  18. Coexisting social conditions and health problems among clients seeking treatment for illicit drug use in Finland: The HUUTI study

    PubMed Central

    2013-01-01

    Background Illicit drug use is an important public health problem. Identifying conditions that coexist with illicit drug use is necessary for planning health services. This study described the prevalence and factors associated with social and health problems among clients seeking treatment for illicit drug use. Methods We carried out cross-sectional analyses of baseline data of 2526 clients who sought treatment for illicit drug use at Helsinki Deaconess Institute between 2001 and 2008. At the clients’ first visit, trained clinicians conducted face-to-face interviews using a structured questionnaire. Logistic regression was used to compute adjusted odds ratios (AORs) and 95% confidence intervals (CIs) for factors associated with social and health problems. Results The mean age of the clients was 25 years, 21% (n = 519) were homeless, 54% (n = 1363) were unemployed and 7% (n = 183) had experienced threats of violence. Half of the clients (50%, n = 1258) were self-referred and 31% (n = 788) used opiates as their primary drugs of abuse. Hepatitis C (25%, n = 630) was more prevalent than other infectious diseases and depressive symptoms (59%, n = 1490) were the most prevalent psychological problems. Clients who were self-referred to treatment were most likely than others to report social problems (AOR = 1.86; 95% CI = 1.50–2.30) and psychological problems (AOR = 1.51; 95% CI = 1.23–1.85). Using opiates as primary drugs of abuse was the strongest factor associated with infectious diseases (AOR = 3.89; 95% CI = 1.32–11.46) and for reporting a combination of social and health problems (AOR = 3.24; 95% CI = 1.58–6.65). Conclusion The existence of illicit drug use with other social and health problems could lead to increased utilisation and cost of healthcare services. Coexisting social and health problems may interfere with clients’ treatment response. Our findings support the call for integration of

  19. "Krokodil":revival of an old drug with new problems.

    PubMed

    Gahr, Maximilian; Freudenmann, Roland W; Hiemke, Christoph; Gunst, Ingo M; Connemann, Bernhard J; Schönfeldt-Lecuona, Carlos

    2012-06-01

    In order to summarize current knowledge about the drug "Krokodil" a systematic review including a literature search of the databases PubMed, Embase, Scopus, and Google was conducted in December 2011. According to information acquired, "Krokodil" is a mixture of several substances and was first reported to have been used in Russia in 2003. The core agent of "Krokodil" is desomorphine, an opioid-analogue that can be easily and cheaply manufactured by oneself. Self-production results in a contaminated suspension that is injected intravenously. Due to its pharmacologic features, desomorphine shows a high potential to cause dependence. Against the background of first possible cases of "Krokodil" use in Western Europe, it appears advisable to provide information regarding the fatal consequences of "Krokodil." PMID:22468632

  20. Problems with the Method of Correlated Vectors

    ERIC Educational Resources Information Center

    Ashton, M.C.; Lee, K.

    2005-01-01

    The method of correlated vectors has been used widely to identify variables that are associated with general intelligence (g). Briefly, this method involves finding the correlation between the vector of intelligence subtests' g-loadings and the vector of those subtests' correlations with the variable in question. We describe two major problems…

  1. An Approximate Matching Method for Clinical Drug Names

    PubMed Central

    Peters, Lee; Kapusnik-Uner, Joan E.; Nguyen, Thang; Bodenreider, Olivier

    2011-01-01

    Objective: To develop an approximate matching method for finding the closest drug names within existing RxNorm content for drug name variants found in local drug formularies. Methods: We used a drug-centric algorithm to determine the closest strings between the RxNorm data set and local variants which failed the exact and normalized string matching searches. Aggressive measures such as token splitting, drug name expansion and spelling correction are used to try and resolve drug names. The algorithm is evaluated against three sets containing a total of 17,164 drug name variants. Results: Mapping of the local variant drug names to the targeted concept descriptions ranged from 83.8% to 92.8% in three test sets. The algorithm identified the appropriate RxNorm concepts as the top candidate in 76.8%, 67.9% and 84.8% of the cases in the three test sets and among the top three candidates in 90–96% of the cases. Conclusion: Using a drug-centric token matching approach with aggressive measures to resolve unknown names provides effective mappings to clinical drug names and has the potential of facilitating the work of drug terminology experts in mapping local formularies to reference terminologies. PMID:22195172

  2. The problems of classification: Method of committees

    NASA Astrophysics Data System (ADS)

    Nikonov, Oleg I.; Chernavin, Fedor P.; Medvedeva, Marina A.

    2016-06-01

    In the paper, we consider a particular case of a neural network - a committee method. The described approach was first introduced by the paper of Ablow and Kaylor (1965). Then further development of the committee machine methods have been carried out by Yekaterinburg pattern recognition school in Institute of Mathematics and Mechanics, Ural Branch of Russian Academy of Sciences Nowadays theory of committee machine structures is based on results of Mazurov and Hachay (1990, 1999).

  3. Meshless Local Petrov-Galerkin Method for Bending Problems

    NASA Technical Reports Server (NTRS)

    Phillips, Dawn R.; Raju, Ivatury S.

    2002-01-01

    Recent literature shows extensive research work on meshless or element-free methods as alternatives to the versatile Finite Element Method. One such meshless method is the Meshless Local Petrov-Galerkin (MLPG) method. In this report, the method is developed for bending of beams - C1 problems. A generalized moving least squares (GMLS) interpolation is used to construct the trial functions, and spline and power weight functions are used as the test functions. The method is applied to problems for which exact solutions are available to evaluate its effectiveness. The accuracy of the method is demonstrated for problems with load discontinuities and continuous beam problems. A Petrov-Galerkin implementation of the method is shown to greatly reduce computational time and effort and is thus preferable over the previously developed Galerkin approach. The MLPG method for beam problems yields very accurate deflections and slopes and continuous moment and shear forces without the need for elaborate post-processing techniques.

  4. Multigrid Methods for Aerodynamic Problems in Complex Geometries

    NASA Technical Reports Server (NTRS)

    Caughey, David A.

    1995-01-01

    Work has been directed at the development of efficient multigrid methods for the solution of aerodynamic problems involving complex geometries, including the development of computational methods for the solution of both inviscid and viscous transonic flow problems. The emphasis is on problems of complex, three-dimensional geometry. The methods developed are based upon finite-volume approximations to both the Euler and the Reynolds-Averaged Navier-Stokes equations. The methods are developed for use on multi-block grids using diagonalized implicit multigrid methods to achieve computational efficiency. The work is focused upon aerodynamic problems involving complex geometries, including advanced engine inlets.

  5. A Focus on Problems of National Interest in the College General Chemistry Laboratory: The Effects of the Problem-Oriented Method Compared with Those of the Traditional Approach.

    ERIC Educational Resources Information Center

    Neman, Robert Lynn

    This study was designed to assess the effects of the problem-oriented method compared to those of the traditional approach in general chemistry at the college level. The problem-oriented course included topics such as air and water pollution, drug addiction and analysis, tetraethyl-lead additives, insecticides in the environment, and recycling of…

  6. Novel Methods of Lipidic Nanoparticle Preparation and Drug Loading

    NASA Astrophysics Data System (ADS)

    Maitani, Y.

    2013-09-01

    In improving cancer chemotherapy, lipidic nanoparticle systems for drug delivery, such as liposomes and emulsions, have received much attention because they are capable of delivering their drug payload selectively to cancer cells and of circulating for a long period in the bloodstream. In addition, lipidic nanoparticles have been examined for use in gene delivery as a non-viral vector. Preparation methods of particles and drug loading methods are crucial for the physicochemical properties of nanoparticles, which are the key aspects for pharmaceutical applications. This review describes new preparation methods for nanoparticles and a loading method for drugs using nanotechnology, including an evaluation of nanoparticles from the point of drug release for applications in cancer therapy and gene delivery.

  7. Homogenization method based on the inverse problem

    SciTech Connect

    Tota, A.; Makai, M.

    2013-07-01

    We present a method for deriving homogeneous multi-group cross sections to replace a heterogeneous region's multi-group cross sections; providing that the fluxes and the currents on the external boundary, and the region averaged fluxes are preserved. The method is developed using diffusion approximation to the neutron transport equation in a symmetrical slab geometry. Assuming that the boundary fluxes are given, two response matrices (RMs) can be defined. The first derives the boundary current from the boundary flux, the second derives the flux integral over the region from the boundary flux. Assuming that these RMs are known, we present a formula which reconstructs the multi-group cross-section matrix and the diffusion coefficients from the RMs of a homogeneous slab. Applying this formula to the RMs of a slab with multiple homogeneous regions yields a homogenization method; which produce such homogenized multi-group cross sections and homogenized diffusion coefficients, that the fluxes and the currents on the external boundary, and the region averaged fluxes are preserved. The method is based on the determination of the eigenvalues and the eigenvectors of the RMs. We reproduce the four-group cross section matrix and the diffusion constants from the RMs in numerical examples. We give conditions for replacing a heterogeneous region by a homogeneous one so that the boundary current and the region-averaged flux are preserved for a given boundary flux. (authors)

  8. Treatment of attentional and hyperactivity problems in children with sympathomimetic drugs: a comprehensive review.

    PubMed

    Jacobvitz, D; Sroufe, L A; Stewart, M; Leffert, N

    1990-09-01

    Issues concerning sympathomimetic drug treatment of children with attentional problems and hyperactivity are considered in light of cumulative and current research. These issues concern the atypical or "paradoxical" drug response of such children, predictability of drug response from neurological or biochemical assessments, and, especially, long-term outcome or effectiveness of sympathomimetic medication. Short-term drug effects on behavior and performance are well documented. However, follow-up studies that exist presently suggest little long-term impact of sympathomimetic drugs on school achievement, peer relationships, or behavior problems in adolescence. Questions remain concerning development of tolerance in children, ways to define subgroups of disordered children who may respond uniquely to stimulants, the efficacy of medication in combination with other treatments, and possible long-term negative consequences of medication. PMID:2228919

  9. Educational Policy and the Drug Problem--A Redistributive Politics Issue

    ERIC Educational Resources Information Center

    Caliguri, Joseph P.

    1975-01-01

    The drug problem exists as a cluster of problems affecting broad interests or groups. The issues are redistributive in that everything relates to everything else. It seems apparent that a cluster of policies and programs need development as well as genuine citizen participation in the formulation of these policies. (Author)

  10. Alcohol and Other Drugs as Cripplers: A Crucial Problem in the Black Community.

    ERIC Educational Resources Information Center

    Darity, William A.

    1979-01-01

    Drug use and abuse, alcoholism, and addiction are the results of deeper social, economic, and political problems. Thus, the negative effects of these substances are more severe in the Black community. Civil rights and other political and social organizations must band together to plan strategies for solving these problems. (Author/GC)

  11. Problems with the Baade-Wesselink method

    NASA Technical Reports Server (NTRS)

    Bohm-Vitense, E.; Garnavich, P.; Lawler, M.; Mena-Werth, J.; Morgan, S.

    1989-01-01

    The discrepancy noted in radii obtained by the Baade-Wesselink method when different colors are used to determine the effective temperatures is explored. The discrepancy is found to be due to an inconsistency in the applied temperature-color calibrations. The assumption of the maximum likelihood method that beta (the effective temperature + 0.1 times the bolometric correction) is a linear function of the color is valid for the B-V and V-I colors, but not for the V-R colors. It is suggested that the errors introduced by the nonlinearity in the relation between beta and the V-R colors will produce radii which are too large. The radii derived from the V-B colors appear to be too small.

  12. Access to generic drugs in the 1950s: the politics of a social problem.

    PubMed Central

    Facchinetti, N J; Dickson, W M

    1982-01-01

    From the published literature of the 1950s, the social history of anti-substitution law is analyzed in terms of sociological theory on the construction of social problems. The analysis reveals how the substitution of generic drugs for prescribed brands came to be recognized as a social problem in need of remedial legislation. The most influential party in the process was the brand-drug industry which centered the debate on matters of public health and professionalism instead of industrial profitability. The industry was able to form a coalition of interests and establish the saliency and legitimacy of the problem, even though there was no objective evidence to establish brand substitution as a hazard to health. The case fits well into the theory of social problem construction. Other issues in health care, particularly drug issues can be studied from this same perspective. PMID:7065335

  13. Analyzing HIV/AIDS and Alcohol and Other Drug Use as a Social Problem

    PubMed Central

    PATTERSON, DAVID A.; Wolf (Adelv unegv Waya), Silver

    2012-01-01

    Most prevention and intervention activities directed toward HIV/AIDS and alcohol and other drug use separately as well as the combining of the two (e.g., those who are both HIV/AIDS and using alcohol and other drugs) comes in the form of specific, individualized therapies without consideration of social influences that may have a greater impact on this population. Approaching this social problem from the narrowed view of individualized, mi-cro solutions disregards the larger social conditions that affect or perhaps even are at the root of the problem. This paper analyzes the social problem of HIV/AIDS and alcohol and other drug abuse using three sociological perspectives—social construction theory, ethnomethodology, and conflict theory—informing the reader of the broader influences accompanying this problem. PMID:23264724

  14. Outcomes of Treatment for Alcohol Problems: Current Methods, Problems, and Results.

    ERIC Educational Resources Information Center

    Nathan, Peter E.; Skinstad, Anne-Helene

    1987-01-01

    Discusses current methods, problems, and results of psychological treatment for alcohol abuse, including alcoholism. Addresses external and internal validity problems specific to issues regarding who is treated for alcohol problems, and treatment and patient factors that predict response to alcoholism treatment. Reviews current data on…

  15. Methods to Design and Synthesize Antibody-Drug Conjugates (ADCs)

    PubMed Central

    Yao, Houzong; Jiang, Feng; Lu, Aiping; Zhang, Ge

    2016-01-01

    Antibody-drug conjugates (ADCs) have become a promising targeted therapy strategy that combines the specificity, favorable pharmacokinetics and biodistributions of antibodies with the destructive potential of highly potent drugs. One of the biggest challenges in the development of ADCs is the application of suitable linkers for conjugating drugs to antibodies. Recently, the design and synthesis of linkers are making great progress. In this review, we present the methods that are currently used to synthesize antibody-drug conjugates by using thiols, amines, alcohols, aldehydes and azides. PMID:26848651

  16. Using Lin's method to solve Bykov's problems

    NASA Astrophysics Data System (ADS)

    Knobloch, Jürgen; Lamb, Jeroen S. W.; Webster, Kevin N.

    2014-10-01

    We consider nonwandering dynamics near heteroclinic cycles between two hyperbolic equilibria. The constituting heteroclinic connections are assumed to be such that one of them is transverse and isolated. Such heteroclinic cycles are associated with the termination of a branch of homoclinic solutions, and called T-points in this context. We study codimension-two T-points and their unfoldings in Rn. In our consideration we distinguish between cases with real and complex leading eigenvalues of the equilibria. In doing so we establish Lin's method as a unified approach to (re)gain and extend results of Bykov's seminal studies and related works. To a large extent our approach reduces the study to the discussion of intersections of lines and spirals in the plane. Case (RR): Under open conditions on the eigenvalues, there exist open sets in parameter space for which there exist periodic orbits close to the heteroclinic cycle. In addition, there exist two one-parameter families of homoclinic orbits to each of the saddle points p1 and p2.See Theorem 2.1 and Proposition 2.2 for precise statements and Fig. 2 for bifurcation diagrams. Cases (RC) and (CC): At the bifurcation point μ=0 and for each N≥2, there exists an invariant set S0N close to the heteroclinic cycle on which the first return map is topologically conjugated to a full shift on N symbols. For any fixed N≥2, the invariant set SμN persists for |μ| sufficiently small.In addition, there exist infinitely many transversal and non-transversal heteroclinic orbits connecting the saddle points p1 and p2 in a neighbourhood of μ=0, as well as infinitely many one-parameter families of homoclinic orbits to each of the saddle points.For full statements of the results see Theorem 2.3 and Propositions 2.4, 2.5 and Fig. 3 for bifurcation diagrams. The dynamics near T-points has been studied previously by Bykov [6-10], Glendinning and Sparrow [20], Kokubu [27,28] and Labouriau and Rodrigues [30,31,38]. See also the surveys

  17. Child abuse, drug addiction and mental health problems of incarcerated women in Israel.

    PubMed

    Chen, Gila; Gueta, Keren

    2015-01-01

    The mental health problems and pathways to drug addiction and crime among female inmates have long been of interest to researchers and practitioners. The purpose of the current study was to examine the possible association between multiple types of childhood abuse, mental health problems, and drug addiction and the incarceration of 50 Israeli women in prison. The findings indicated that female inmates come from risky families with a high prevalence of family mental health problems, parental drug addiction and crime, and sibling drug addiction and crime. Furthermore, they revealed that incarcerated women from risky families were victims of multiple types of childhood abuse and neglect by their parents, as well as their siblings. Overall, the results suggest that the adverse consequences of a family's mental health problems are much more dramatic than we assumed to date, and that women are more likely than men to be the victims of multiple types of childhood abuse and neglect, as well as suffering more severe psychiatric problems, depression, and drug addiction. The implications of these findings are discussed. PMID:25660063

  18. The Method of Problems versus the Method of Topics

    ERIC Educational Resources Information Center

    Eidlin, Fred

    2011-01-01

    Confused students researching papers not knowing where they are going. Articles, lectures, and books on exciting topics that turn out to be boring. Such familiar phenomena are symptoms of a widespread, largely unconscious methodological habit of focusing on topics rather than problems. This habit rests on views about knowledge that are deeply…

  19. Solving Fluid Structure Interaction Problems with an Immersed Boundary Method

    NASA Technical Reports Server (NTRS)

    Barad, Michael F.; Brehm, Christoph; Kiris, Cetin C.

    2016-01-01

    An immersed boundary method for the compressible Navier-Stokes equations can be used for moving boundary problems as well as fully coupled fluid-structure interaction is presented. The underlying Cartesian immersed boundary method of the Launch Ascent and Vehicle Aerodynamics (LAVA) framework, based on the locally stabilized immersed boundary method previously presented by the authors, is extended to account for unsteady boundary motion and coupled to linear and geometrically nonlinear structural finite element solvers. The approach is validated for moving boundary problems with prescribed body motion and fully coupled fluid structure interaction problems. Keywords: Immersed Boundary Method, Higher-Order Finite Difference Method, Fluid Structure Interaction.

  20. A Modified Alternating Direction Method for Variational Inequality Problems

    SciTech Connect

    Han, D.

    2002-07-01

    The alternating direction method is an attractive method for solving large-scale variational inequality problems whenever the subproblems can be solved efficiently. However, the subproblems are still variational inequality problems, which are as structurally difficult to solve as the original one. To overcome this disadvantage, in this paper we propose a new alternating direction method for solving a class of nonlinear monotone variational inequality problems. In each iteration the method just makes an orthogonal projection to a simple set and some function evaluations. We report some preliminary computational results to illustrate the efficiency of the method.

  1. Data sources and methods for ascertaining human exposure to drugs.

    PubMed

    Jones, J K; Kennedy, D L

    Estimates of population exposure based on drug use data are critical elements in the post marketing surveillance of drugs and provide a context for assessing the various risks and benefits associated with drug treatment. Such information is important in predicting morbidity and planning public health protection strategies, indepth studies, and regulatory actions. Knowledge that a population of one thousand instead of one million may potentially be exposed to a drug can help determine how a particular regulatory problem will be handled and would obviously be a major determinant in designing a case-control or cohort study. National estimates of drug use give an overview of the most commonly used drug therapies in current practice. They also furnish valuable comparison data for specific studies of drug use limited to one group of drugs, one geographic region, or one medical care setting. The FDA has access to several different national drug use data bases, each measuring a different point in the drug distribution channels. None covers the entire spectrum of drug exposures. The major "holes" in this patchwork of data bases are the inability to measure OTC drug use with any accuracy and the lack of qualitative information on drug use in hospitals. In addition, there is no patient linkage with the data. The data can only show trends in drug use. They impart no sense of the longitudinal use of drugs for individual patients. There is no direct connection between the different data bases, all of which have their own sampling frames and their own projection methodologies. The market research companies have complete control over these methodologies and they are subject to periodic changes, a situation not entirely satisfactory for epidemiologic research. Sometimes it is a struggle to keep up with these changes. Over the past two years, every one of these data bases has undergone some type of sampling or projection methodology change. One important limitation to the use of all

  2. Applications of Genetic Methods to NASA Design and Operations Problems

    NASA Technical Reports Server (NTRS)

    Laird, Philip D.

    1996-01-01

    We review four recent NASA-funded applications in which evolutionary/genetic methods are important. In the process we survey: the kinds of problems being solved today with these methods; techniques and tools used; problems encountered; and areas where research is needed. The presentation slides are annotated briefly at the top of each page.

  3. Correlates of Problem Drinking and Drug Use in Black Sexual Assault Victims.

    PubMed

    Long, LaDonna; Ullman, Sarah E

    2016-01-01

    Few studies have examined factors related to problem drinking and drug use in Black sexual assault victims. Given that sexual assault and histories of trauma are associated with substance abuse in victims, research is needed to determine what factors may be related to these outcomes for Black survivors. Furthermore, child sexual abuse (CSA) is a risk factor for substance abuse, but no studies have examined correlates of substance abuse outcomes separately according to CSA history. This study examines a large diverse sample of Black sexual assault victims (N = 495) to determine the associations of demographics, trauma history, assault characteristics, and postassault psychosocial factors with problem drinking and drug use using multivariate regressions. Traumatic life events, using substances to cope and self-blame, were associated with greater problem drinking and drug use. Implications for practitioners and policymakers are discussed. PMID:26646054

  4. Methods to sustain drug efficacy in helminth control programmes.

    PubMed

    Albonico, M

    2003-05-01

    Assessment of the efficacy of anthelminthic treatment in public health is a broad concept, which goes beyond parasitological methods and should be clearly defined according to several indicators of morbidity. Several factors may influence the efficacy of anthelminthic drugs. The quality of drug is an issue of great importance, especially when produced locally as a generic product and used in large-scale chemotherapy-based control programmes. Other factors include the drug-patient interaction, the host-parasite relationship, the diagnostic method used, genetic variations between parasite strains and induced drug resistance. Veterinary scientists have warned that drug resistance can be selected through frequent mass treatment of sheep and goats and have developed a body of knowledge on evaluation of efficacy and detection of resistance in nematodes of veterinary importance. In soil-transmitted nematodes infections of humans, the egg reduction rate (ERR), the egg hatch assay (EHA) and novel molecular biological techniques may be used to monitor drug efficacy in helminth control programmes and to detect early occurrence of resistance. Evidence of reduced drug efficacy of some anthelminthics has been suggested by recent studies and strategies to prevent or delay the emergence of drug resistance in human soil-transmitted nematodes. PMID:12745140

  5. Problem alcohol use among problem drug users in primary care: a qualitative study of what patients think about screening and treatment

    PubMed Central

    2013-01-01

    Background Problem alcohol use is common and associated with considerable adverse outcomes among patients who attend primary care in Ireland and other European countries for opiate substitution treatment. This paper aims to describe patients’ experience of, and attitude towards, screening and therapeutic interventions for problem alcohol use in primary care. Methods This qualitative study recruited problem drug users (N = 28) from primary care based methadone programmes in the Ireland’s Eastern region, using a stratified sampling matrix to include size of general practice and geographical area. Semi-structured interviews were conducted and analysed using thematic analysis, and audited by a third reviewer. Results We identified three overarching themes relevant to the purpose of this paper: (1) patients’ experience of, and (2) attitude towards, screening and treatment for problem alcohol use in primary care, as well as their (3) views on service improvement. While most patients reported being screened for problem alcohol use at initial assessment, few recalled routine screening or treatment. Among the barriers and enablers to screening and treatment, patients highlighted the importance of the practitioner-patient relationship in helping them address the issue. Nevertheless, patients felt that healthcare professionals should be more proactive in the management of problem alcohol use at a primary care level and that primary care can play an important role in their treatment. Conclusions Problem alcohol use is an important challenge in the care of problem drug users. While primary care is well placed to address this issue, little data has reported on this topic. The development of interventions which promote screening and brief interventions in practice are likely to benefit this at-risk group and further research and education, that help achieve this goal, are a priority. Strategies such as dissemination of clinical guidelines, educational videos, academic

  6. Finite element method for eigenvalue problems in electromagnetics

    NASA Technical Reports Server (NTRS)

    Reddy, C. J.; Deshpande, Manohar D.; Cockrell, C. R.; Beck, Fred B.

    1994-01-01

    Finite element method (FEM) has been a very powerful tool to solve many complex problems in electromagnetics. The goal of the current research at the Langley Research Center is to develop a combined FEM/method of moments approach to three-dimensional scattering/radiation problem for objects with arbitrary shape and filled with complex materials. As a first step toward that goal, an exercise is taken to establish the power of FEM, through closed boundary problems. This paper demonstrates the developed of FEM tools for two- and three-dimensional eigenvalue problems in electromagnetics. In section 2, both the scalar and vector finite elements have been used for various waveguide problems to demonstrate the flexibility of FEM. In section 3, vector finite element method has been extended to three-dimensional eigenvalue problems.

  7. A Novel Numerical Method for Fuzzy Boundary Value Problems

    NASA Astrophysics Data System (ADS)

    Can, E.; Bayrak, M. A.; Hicdurmaz

    2016-05-01

    In the present paper, a new numerical method is proposed for solving fuzzy differential equations which are utilized for the modeling problems in science and engineering. Fuzzy approach is selected due to its important applications on processing uncertainty or subjective information for mathematical models of physical problems. A second-order fuzzy linear boundary value problem is considered in particular due to its important applications in physics. Moreover, numerical experiments are presented to show the effectiveness of the proposed numerical method on specific physical problems such as heat conduction in an infinite plate and a fin.

  8. Extension of modified power method to two-dimensional problems

    NASA Astrophysics Data System (ADS)

    Zhang, Peng; Lee, Hyunsuk; Lee, Deokjung

    2016-09-01

    In this study, the generalized modified power method was extended to two-dimensional problems. A direct application of the method to two-dimensional problems was shown to be unstable when the number of requested eigenmodes is larger than a certain problem dependent number. The root cause of this instability has been identified as the degeneracy of the transfer matrix. In order to resolve this instability, the number of sub-regions for the transfer matrix was increased to be larger than the number of requested eigenmodes; and a new transfer matrix was introduced accordingly which can be calculated by the least square method. The stability of the new method has been successfully demonstrated with a neutron diffusion eigenvalue problem and the 2D C5G7 benchmark problem.

  9. Medication reviews in primary care in Sweden: importance of clinical pharmacists' recommendations on drug-related problems.

    PubMed

    Modig, Sara; Holmdahl, Lydia; Bondesson, Åsa

    2016-02-01

    Background One way of preventing and solving drug-related problems in frail elderly is to perform team-based medication reviews. Objective To evaluate the quality of the clinical pharmacy service to primary care using structured medication reviews, focusing on the clinical significance of the recommendations made by clinical pharmacists. Setting A random sample of 150 patients (out of 1541) who received structured team based medication reviews. The patients lived at a geriatric nursing home or were ≥65 years and lived in ordinary housing with medication-related community help. Method Based on information on symptoms, kidney function, blood pressure, diagnoses and the medication list, a pharmacist identified possible drug-related problems and supplied recommendations for the general practitioner to act on. Two independent physicians retrospectively ranked the clinical significance of the recommendations according to Hatoum, with rankings ranging between 1 (adverse significance) and 6 (extremely significant). Main outcome measure The clinical significance of the recommendations. Results In total 349 drug-related problems were identified, leading to recommendations. The vast majority of the recommendations (96 %) were judged to have significance 3 or higher and more than the half were judged to have significance 4 or higher. Conclusion The high proportion of clinically significant recommendations provided by pharmacists when performing team-based medication reviews suggest that these clinical pharmacy services have potential to increase prescribing quality. As such, the medication reviews have the potential for contributing to a better and safer drug therapy for elderly patients. PMID:26582483

  10. Application of supercritical antisolvent method in drug encapsulation: a review

    PubMed Central

    Kalani, Mahshid; Yunus, Robiah

    2011-01-01

    The review focuses on the application of supercritical fluids as antisolvents in the pharmaceutical field and demonstrates the supercritical antisolvent method in the use of drug encapsulation. The main factors for choosing the solvent and biodegradable polymer to produce fine particles to ensure effective drug delivery are emphasized and the effect of polymer structure on drug encapsulation is illustrated. The review also demonstrates the drug release mechanism and polymeric controlled release system, and discusses the effects of the various conditions in the process, such as pressure, temperature, concentration, chemical compositions (organic solvents, drug, and biodegradable polymer), nozzle geometry, CO2 flow rate, and the liquid phase flow rate on particle size and its distribution. PMID:21796245

  11. Fluorescence And Alternative Methods In Urine Drug Testing

    NASA Astrophysics Data System (ADS)

    Jain, Naresh C.

    1988-04-01

    Drug abuse has become-one of the most compelling realities _ ot contemporary society. It has penetrated every segment ot our population: trom schools to sports and trom organized crime to board rooms . Drugs in tie w9rkplace allegedly cost government agencies and business millions ot dollars each year in increased absenteeism,. poor work performance, thefts,accidents andwastedtime. The President's Commission on Organized Crime and the federal government are in tavor ot urine drug testing. In fact many employers are now resorting to urine drug testing on current and prospective employees. This presep.tation discusses different laboratory methods used in urine drug.testing, including immunoassays, fluorescence polarization, thin layer chromatography, high pressure liquid chromatography, gas chromatography and gas-chromatography-mass spectrometry.

  12. In silico methods for drug repurposing and pharmacology.

    PubMed

    Hodos, Rachel A; Kidd, Brian A; Shameer, Khader; Readhead, Ben P; Dudley, Joel T

    2016-05-01

    Data in the biological, chemical, and clinical domains are accumulating at ever-increasing rates and have the potential to accelerate and inform drug development in new ways. Challenges and opportunities now lie in developing analytic tools to transform these often complex and heterogeneous data into testable hypotheses and actionable insights. This is the aim of computational pharmacology, which uses in silico techniques to better understand and predict how drugs affect biological systems, which can in turn improve clinical use, avoid unwanted side effects, and guide selection and development of better treatments. One exciting application of computational pharmacology is drug repurposing-finding new uses for existing drugs. Already yielding many promising candidates, this strategy has the potential to improve the efficiency of the drug development process and reach patient populations with previously unmet needs such as those with rare diseases. While current techniques in computational pharmacology and drug repurposing often focus on just a single data modality such as gene expression or drug-target interactions, we argue that methods such as matrix factorization that can integrate data within and across diverse data types have the potential to improve predictive performance and provide a fuller picture of a drug's pharmacological action. WIREs Syst Biol Med 2016, 8:186-210. doi: 10.1002/wsbm.1337 For further resources related to this article, please visit the WIREs website. PMID:27080087

  13. On 2D bisection method for double eigenvalue problems

    SciTech Connect

    Ji, X.

    1996-06-01

    The two-dimensional bisection method presented in (SIAM J. Matrix Anal. Appl. 13(4), 1085 (1992)) is efficient for solving a class of double eigenvalue problems. This paper further extends the 2D bisection method of full matrix cases and analyses its stability. As in a single parameter case, the 2D bisection method is very stable for the tridiagonal matrix triples satisfying the symmetric-definite condition. Since the double eigenvalue problems arise from two-parameter boundary value problems, an estimate of the discretization error in eigenpairs is also given. Some numerical examples are included. 42 refs., 1 tab.

  14. Schwarz alternating methods for anisotropic problems with prolate spheroid boundaries.

    PubMed

    Dai, Zhenlong; Du, Qikui; Liu, Baoqing

    2016-01-01

    The Schwarz alternating algorithm, which is based on natural boundary element method, is constructed for solving the exterior anisotropic problem in the three-dimension domain. The anisotropic problem is transformed into harmonic problem by using the coordinate transformation. Correspondingly, the algorithm is also changed. Continually, we analysis the convergence and the error estimate of the algorithm. Meanwhile, we give the contraction factor for the convergence. Finally, some numerical examples are computed to show the efficiency of this algorithm. PMID:27625977

  15. Newton's method for large bound-constrained optimization problems.

    SciTech Connect

    Lin, C.-J.; More, J. J.; Mathematics and Computer Science

    1999-01-01

    We analyze a trust region version of Newton's method for bound-constrained problems. Our approach relies on the geometry of the feasible set, not on the particular representation in terms of constraints. The convergence theory holds for linearly constrained problems and yields global and superlinear convergence without assuming either strict complementarity or linear independence of the active constraints. We also show that the convergence theory leads to an efficient implementation for large bound-constrained problems.

  16. Overview of Krylov subspace methods with applications to control problems

    NASA Technical Reports Server (NTRS)

    Saad, Youcef

    1989-01-01

    An overview of projection methods based on Krylov subspaces are given with emphasis on their application to solving matrix equations that arise in control problems. The main idea of Krylov subspace methods is to generate a basis of the Krylov subspace Span and seek an approximate solution the the original problem from this subspace. Thus, the original matrix problem of size N is approximated by one of dimension m typically much smaller than N. Krylov subspace methods have been very successful in solving linear systems and eigenvalue problems and are now just becoming popular for solving nonlinear equations. It is shown how they can be used to solve partial pole placement problems, Sylvester's equation, and Lyapunov's equation.

  17. Factors related to the process of seeking and completing treatment for drug abuse (qualitative methods in drug abuse research).

    PubMed

    Otiashvili, D; Djordjevic, A; Morales, D; Parsons, A; Platt, E; Stempliuk, V

    2005-05-01

    Numerous studies have demonstrated the effectiveness of drug abuse treatment. Yet many drug abusers do not enter treatment, many who do enter leave prematurely, and relapse following treatment is common. Understanding motivation for change and treatment readiness is key to understanding how to induct and engage drug users in treatment. To the extent that treatment programs focus initially on reducing drug use, rather than psychosocial problems that motivate individuals to seek treatment, treatment programs may fail to meet the primary needs of users and thus fail to attract or engage them. Outcomes of substance abuse treatment programs historically have been measured by successful program completion, reduced drug use and illegal activity, and improved social functioning (employment, education etc). There is minimal reference to client expectations of treatment and factors that influenced treatment-seeking behavior. Studies that have assessed client dropout from substance abuse treatment have generally focused upon quantitative measures that attempt to determine what types of clients drop out or stay, or what types of characteristics best predict client dropout. Qualitative methods are the most appropriate to fill these gaps in substance abuse treatment research. PMID:15988078

  18. Meshless method for solving fixed boundary problem of plasma equilibrium

    NASA Astrophysics Data System (ADS)

    Imazawa, Ryota; Kawano, Yasunori; Itami, Kiyoshi

    2015-07-01

    This study solves the Grad-Shafranov equation with a fixed plasma boundary by utilizing a meshless method for the first time. Previous studies have utilized a finite element method (FEM) to solve an equilibrium inside the fixed separatrix. In order to avoid difficulties of FEM (such as mesh problem, difficulty of coding, expensive calculation cost), this study focuses on the meshless methods, especially RBF-MFS and KANSA's method to solve the fixed boundary problem. The results showed that CPU time of the meshless methods was ten to one hundred times shorter than that of FEM to obtain the same accuracy.

  19. Faculty Member's Handbook. Strategies for Preventing Alcohol and Other Drug Problems. The College Series.

    ERIC Educational Resources Information Center

    CSR, Inc., Washington, DC.

    This handbook for higher education faculty is designed to inform them of the nature and extent of alcohol and other drug abuse on the nation's campuses and to enlist their involvement in responding to these problems. Based on the premise that each individual can make a difference, the faculty member is encouraged to help shape the campus…

  20. Fictitious domain method for unsteady problems: Application to electromagnetic scattering

    SciTech Connect

    Collino, F.; Joly, P.; Millot, F.

    1997-12-01

    This paper investigates the use of a fictitious domain method as an alternative numerical method (compared to finite difference and finite element methods) for handling problems dealing with two-dimensional scattering by an obstacle. An example of this would be electromagnetic waves scattered from a perfectly conducting boundaries.

  1. Diffuse interface methods for inverse problems: case study for an elliptic Cauchy problem

    NASA Astrophysics Data System (ADS)

    Burger, Martin; Løseth Elvetun, Ole; Schlottbom, Matthias

    2015-12-01

    Many inverse problems have to deal with complex, evolving and often not exactly known geometries, e.g. as domains of forward problems modeled by partial differential equations. This makes it desirable to use methods which are robust with respect to perturbed or not well resolved domains, and which allow for efficient discretizations not resolving any fine detail of those geometries. For forward problems in partial differential equations methods based on diffuse interface representations have gained strong attention in the last years, but so far they have not been considered systematically for inverse problems. In this work we introduce a diffuse domain method as a tool for the solution of variational inverse problems. As a particular example we study ECG inversion in further detail. ECG inversion is a linear inverse source problem with boundary measurements governed by an anisotropic diffusion equation, which naturally cries for solutions under changing geometries, namely the beating heart. We formulate a regularization strategy using Tikhonov regularization and, using standard source conditions, we prove convergence rates. A special property of our approach is that not only operator perturbations are introduced by the diffuse domain method, but more important we have to deal with topologies which depend on a parameter \\varepsilon in the diffuse domain method, i.e. we have to deal with \\varepsilon -dependent forward operators and \\varepsilon -dependent norms. In particular the appropriate function spaces for the unknown and the data depend on \\varepsilon . This prevents the application of some standard convergence techniques for inverse problems, in particular interpreting the perturbations as data errors in the original problem does not yield suitable results. We consequently develop a novel approach based on saddle-point problems. The numerical solution of the problem is discussed as well and results for several computational experiments are reported. In

  2. [Methods for teaching problem-solving in medical schools].

    PubMed

    Shumway, J M; Vargas, M E; Heller, L E

    1984-01-01

    The need to include in the medical curriculum instructional activities to promote the development of problem-solving abilities has been asserted at the national and international levels. In research on the mental process involved in the solution of problems in medicine, problem-solving has been defined as a hypothetical-deductive activity engaged in by experienced physicians, in which the early generation of hypotheses influences the subsequent gathering of information. This article comments briefly on research on the mental process by which medical problems are solved. It describes the methods that research has shown to be most applicable in instruction to develop problem-solving abilities, and presents some educational principles that justify their application. The "trail-following" approach is the method that has been most commonly used to study the physician's problem-solving behavior. The salient conclusions from this research are that in the problem-solving process the diagnostic hypothesis is generated very early on and with limited data; the number of hypotheses is small; the problem-solving approach is specific to the type of medical problem and case in hand; and the accumulation of medical knowledge and experience forms the basis of clinical competence. Four methods for teaching the solution of problems are described: case presentation, the rain of ideas, the nominal groups technique and decision-making consensus, the census and analysis of forces in the field, and the analysis of clinical decisions. These methods are carried out in small groups. The advantages of the small groups are that the students are active participants in the learning process, they receive formative evaluation of their performance in a setting conductive to learning, and are able to interact with their instructor if he makes proper use of the right questioning techniques. While no single problem-solving method can be useful to all students or in all the problems they encounter

  3. A reduced basis Landweber method for nonlinear inverse problems

    NASA Astrophysics Data System (ADS)

    Garmatter, Dominik; Haasdonk, Bernard; Harrach, Bastian

    2016-03-01

    We consider parameter identification problems in parametrized partial differential equations (PDEs). These lead to nonlinear ill-posed inverse problems. One way of solving them is using iterative regularization methods, which typically require numerous amounts of forward solutions during the solution process. In this article we consider the nonlinear Landweber method and couple it with the reduced basis method as a model order reduction technique in order to reduce the overall computational time. In particular, we consider PDEs with a high-dimensional parameter space, which are known to pose difficulties in the context of reduced basis methods. We present a new method that is able to handle such high-dimensional parameter spaces by combining the nonlinear Landweber method with adaptive online reduced basis updates. It is then applied to the inverse problem of reconstructing the conductivity in the stationary heat equation.

  4. Parallel decomposition methods for the solution of electromagnetic scattering problems

    NASA Technical Reports Server (NTRS)

    Cwik, Tom

    1992-01-01

    This paper contains a overview of the methods used in decomposing solutions to scattering problems onto coarse-grained parallel processors. Initially, a short summary of relevant computer architecture is presented as background to the subsequent discussion. After the introduction of a programming model for problem decomposition, specific decompositions of finite difference time domain, finite element, and integral equation solutions to Maxwell's equations are presented. The paper concludes with an outline of possible software-assisted decomposition methods and a summary.

  5. Look-alike and sound-alike drug names: the problem and the solution.

    PubMed

    Davis, N M; Cohen, M R; Teplitsky, B

    1992-02-01

    This list of 645 pairs of look-alike and sound-alike drug names (1,290 names are shown; they are listed both ways), has been complied to graphically emphasize the importance for the pharmaceutical industry, the United States Adopted Name (USAN) Council, and Food and Drug Administration (FDA) to select new names with great care. It also stresses to health professionals the necessity of writing legibly, writing complete orders, speaking slowly and clearly when giving verbal orders, carefully reading prescription orders, knowing what is wrong with patients, maintaining records of previous drugs patients have received, and learning about new drug products. It also indicates that patients must be educated about the medications they are taking. Your cooperation in alerting the authors of names they may have overlooked or of new problems would be greatly appreciated. When a sufficient number of additions are received, an updated list will be published. PMID:10183617

  6. History and evolution of methods for solving the inverse problem.

    PubMed

    van Oosterom, A

    1991-10-01

    This article serves as an introduction to the other articles in this issue devoted to the problem of the localization of neural generators. Elements of the theory of electric volume conduction are briefly introduced, as far as these apply to the interpretation of observed scalp potentials. First, some basic methods for display of the different aspects of the spatiotemporal information are described. Next, the most prominent source and volume conductor models that have been postulated for the involved forward problem are summarized. The problems of source identification and source localization, known as the inverse problem, are then formulated in terms of a parameter estimation procedure. The importance of introducing a priori information in the inverse problem, aimed at stabilizing (regularizing) the obtained solution, is emphasized. Methods for imposing such constraints are briefly outlined. PMID:1761703

  7. Spectral finite-element methods for parametric constrained optimization problems.

    SciTech Connect

    Anitescu, M.; Mathematics and Computer Science

    2009-01-01

    We present a method to approximate the solution mapping of parametric constrained optimization problems. The approximation, which is of the spectral finite element type, is represented as a linear combination of orthogonal polynomials. Its coefficients are determined by solving an appropriate finite-dimensional constrained optimization problem. We show that, under certain conditions, the latter problem is solvable because it is feasible for a sufficiently large degree of the polynomial approximation and has an objective function with bounded level sets. In addition, the solutions of the finite-dimensional problems converge for an increasing degree of the polynomials considered, provided that the solutions exhibit a sufficiently large and uniform degree of smoothness. Our approach solves, in the case of optimization problems with uncertain parameters, the most computationally intensive part of stochastic finite-element approaches. We demonstrate that our framework is applicable to parametric eigenvalue problems.

  8. A weak Hamiltonian finite element method for optimal control problems

    NASA Technical Reports Server (NTRS)

    Hodges, Dewey H.; Bless, Robert R.

    1989-01-01

    A temporal finite element method based on a mixed form of the Hamiltonian weak principle is developed for dynamics and optimal control problems. The mixed form of Hamilton's weak principle contains both displacements and momenta as primary variables that are expanded in terms of nodal values and simple polynomial shape functions. Unlike other forms of Hamilton's principle, however, time derivatives of the momenta and displacements do not appear therein; instead, only the virtual momenta and virtual displacements are differentiated with respect to time. Based on the duality that is observed to exist between the mixed form of Hamilton's weak principle and variational principles governing classical optimal control problems, a temporal finite element formulation of the latter can be developed in a rather straightforward manner. Several well-known problems in dynamics and optimal control are illustrated. The example dynamics problem involves a time-marching problem. As optimal control examples, elementary trajectory optimization problems are treated.

  9. A weak Hamiltonian finite element method for optimal control problems

    NASA Technical Reports Server (NTRS)

    Hodges, Dewey H.; Bless, Robert R.

    1990-01-01

    A temporal finite element method based on a mixed form of the Hamiltonian weak principle is developed for dynamics and optimal control problems. The mixed form of Hamilton's weak principle contains both displacements and momenta as primary variables that are expanded in terms of nodal values and simple polynomial shape functions. Unlike other forms of Hamilton's principle, however, time derivatives of the momenta and displacements do not appear therein; instead, only the virtual momenta and virtual displacements are differentiated with respect to time. Based on the duality that is observed to exist between the mixed form of Hamilton's weak principle and variational principles governing classical optimal control problems, a temporal finite element formulation of the latter can be developed in a rather straightforward manner. Several well-known problems in dynamics and optimal control are illustrated. The example dynamics problem involves a time-marching problem. As optimal control examples, elementary trajectory optimization problems are treated.

  10. Weak Hamiltonian finite element method for optimal control problems

    NASA Technical Reports Server (NTRS)

    Hodges, Dewey H.; Bless, Robert R.

    1991-01-01

    A temporal finite element method based on a mixed form of the Hamiltonian weak principle is developed for dynamics and optimal control problems. The mixed form of Hamilton's weak principle contains both displacements and momenta as primary variables that are expanded in terms of nodal values and simple polynomial shape functions. Unlike other forms of Hamilton's principle, however, time derivatives of the momenta and displacements do not appear therein; instead, only the virtual momenta and virtual displacements are differentiated with respect to time. Based on the duality that is observed to exist between the mixed form of Hamilton's weak principle and variational principles governing classical optimal control problems, a temporal finite element formulation of the latter can be developed in a rather straightforward manner. Several well-known problems in dynamics and optimal control are illustrated. The example dynamics problem involves a time-marching problem. As optimal control examples, elementary trajectory optimization problems are treated.

  11. Alternating method applied to edge and surface crack problems.

    NASA Technical Reports Server (NTRS)

    Hartranft, R. J.; Sih, G. C.

    1973-01-01

    The alternating method, which intimately combines analytical results with numerical calculations, as applied to edge crack problems in two dimensions and surface crack problems in three dimensions, is treated. The case of a crack perpendicular to the edge of a semiinfinite material is considered. One of the crack geometries that has received continual interest in fracture mechanics is that of a semielliptical crack whose major axis lies on a stress free surface. In order to demonstrate the sensitivity of the solution to the influence of the free surface the semicircular crack problem is again treated by the alternating method.

  12. Finite element methods for nonlinear elastostatic problems in rubber elasticity

    NASA Technical Reports Server (NTRS)

    Oden, J. T.; Becker, E. B.; Miller, T. H.; Endo, T.; Pires, E. B.

    1983-01-01

    A number of finite element methods for the analysis of nonlinear problems in rubber elasticity are outlined. Several different finite element schemes are discussed. These include the augmented Lagrangian method, continuation or incremental loading methods, and associated Riks-type methods which have the capability of incorporating limit point behavior and bifurcations. Algorithms for the analysis of limit point behavior and bifurcations are described and the results of several numerical experiments are presented. In addition, a brief survey of some recent work on modelling contact and friction in elasticity problems is given. These results pertain to the use of new nonlocal and nonlinear friction laws.

  13. Analytical methods for abused drugs in hair and their applications.

    PubMed

    Wada, Mitsuhiro; Ikeda, Rie; Kuroda, Naotaka; Nakashima, Kenichiro

    2010-06-01

    Hair has been focused on for its usability as an alternative biological specimen to blood and urine for determining drugs of abuse in fields such as forensic and toxicological sciences because hair can be used to elucidate the long intake history of abused drugs compared with blood and urine. Hair analysis consists of several pretreatment steps, such as washing out contaminates from hair, extraction of target compounds from hair, and cleanup for instrumental analysis. Each step includes characteristic and independent features for the class of drugs, e.g., stimulants, narcotics, cannabis, and other medicaments. In this review, recently developed methods to determine drugs of abuse are summarized, and the pretreatment steps as well as the sensitivity and applicability are critically discussed. PMID:20232061

  14. Solution of Exterior Acoustic Problems by the Boundary Element Method.

    NASA Astrophysics Data System (ADS)

    Kirkup, Stephen Martin

    Available from UMI in association with The British Library. The boundary element method is described and investigated, especially in respect of its application to exterior two -dimensional Laplace problems. Both empirical and algebraic analyses (including the effects of approximation of the boundary and boundary functions and the precision of the evaluation of the discrete forms) are developed. Methods for the automatic evaluation of the discrete forms of the Laplace and Helmholtz integral operators are reviewed and extended. Boundary element methods for the solution of exterior Helmholtz problems with general (but most importantly Neumann) boundary conditions are reviewed and some are explicitly stated using a new notation. Boundary element methods based on the boundary integral equations introduced by Brakhage & Werner/ Leis/ Panich/ Kussmaul (indirect) and Burton & Miller (direct) are given prime consideration and implemented for three -dimensional problems. The influence of the choice of weighting parameter on the performance of the methods is explored and further guidance is given. The application of boundary element methods and methods based on the Rayleigh integral to acoustic radiation problems are considered. Methods for speeding up their solution via the boundary element method are developed. Library subroutines for the solution of acoustic radiation problems are described and demonstrated. Computational techniques for the problem of predicting the noise produced by a running engine are reviewed and appraised. The application of the boundary element method to low-noise engine design and in the design of noise shields is considered. The boundary element method is applied to the Ricardo crankcase simulation rig, which is an engine -like structure. A comparison of predicted and measured sound power spectra is given.

  15. Solution of exterior acoustic problems by the boundary element method

    NASA Astrophysics Data System (ADS)

    Kirkup, Stephen Martin

    The boundary element method is described and investigated, especially in respect of its application to exterior two-dimensional Laplace problems. Both empirical and algebraic analyses (including the effects of approximation of the boundary and boundary functions and the precision of the evaluation of the discrete forms) are developed. Methods for the automatic evaluation of the discrete forms of the Laplace and Helmholtz integral operators are reviewed and extended. Boundary element methods for the solution of exterior Helmholtz problems with general (but most importantly Neumann) boundary conditions are reviewed and some are explicitly stated using a new notation. Boundary element methods based on the boundary integral equations introduced by Brakhage and Werner/Leis/Panich/Kussmaul (indirect) and Burton and Miller (direct) are given prime consideration and implemented for three-dimensional problems. The influence of the choice of weighting parameter on the performance of the methods is explored and further guidance is given. The application of boundary element methods and methods based on the Rayleigh integral to acoustic radiation problems are considered. Methods for speeding up their solution via the boundary element method are developed. Library subroutines for the solution of acoustic radiation problems are described and demonstrated. Computational techniques for the problem of predicting the noise produced by a running engine are reviewed and appraised. The application of the boundary element method to low-noise engine design and in the design of noise shields is considered. The boundary element method is applied to the Ricardo crankcase simulation rig, which is an engine-like structure. A comparison of predicted and measured sound power spectra is given.

  16. Explicit methods in extended phase space for inseparable Hamiltonian problems

    NASA Astrophysics Data System (ADS)

    Pihajoki, Pauli

    2015-03-01

    We present a method for explicit leapfrog integration of inseparable Hamiltonian systems by means of an extended phase space. A suitably defined new Hamiltonian on the extended phase space leads to equations of motion that can be numerically integrated by standard symplectic leapfrog (splitting) methods. When the leapfrog is combined with coordinate mixing transformations, the resulting algorithm shows good long term stability and error behaviour. We extend the method to non-Hamiltonian problems as well, and investigate optimal methods of projecting the extended phase space back to original dimension. Finally, we apply the methods to a Hamiltonian problem of geodesics in a curved space, and a non-Hamiltonian problem of a forced non-linear oscillator. We compare the performance of the methods to a general purpose differential equation solver LSODE, and the implicit midpoint method, a symplectic one-step method. We find the extended phase space methods to compare favorably to both for the Hamiltonian problem, and to the implicit midpoint method in the case of the non-linear oscillator.

  17. Domain decomposition methods for solving an image problem

    SciTech Connect

    Tsui, W.K.; Tong, C.S.

    1994-12-31

    The domain decomposition method is a technique to break up a problem so that ensuing sub-problems can be solved on a parallel computer. In order to improve the convergence rate of the capacitance systems, pre-conditioned conjugate gradient methods are commonly used. In the last decade, most of the efficient preconditioners are based on elliptic partial differential equations which are particularly useful for solving elliptic partial differential equations. In this paper, the authors apply the so called covering preconditioner, which is based on the information of the operator under investigation. Therefore, it is good for various kinds of applications, specifically, they shall apply the preconditioned domain decomposition method for solving an image restoration problem. The image restoration problem is to extract an original image which has been degraded by a known convolution process and additive Gaussian noise.

  18. Do adolescent drug use consequences predict externalizing and internalizing problems in emerging adulthood as well as traditional drug use measures in a Hispanic sample?

    PubMed Central

    Grigsby, Timothy J.; Forster, Myriam; Baezconde-Garbanati, Lourdes; Soto, Daniel W.; Unger, Jennifer B.

    2014-01-01

    The present study compares statistical models for three conceptualizations of drug use in 11th grade (past 30 day ever/never use, past 30 day frequency of drug use and past 30 day drug use consequences) with externalizing and internalizing problems in emerging adulthood when controlling for age, academic achievement and socioeconomic status in a Hispanic sample. Multivariate logistic regression models for the different drug use variables were compared when modeling weapon carrying, arrest, multiple lifetime sex partners, drug/alcohol use before sex and condom use in emerging adulthood. A multivariate linear regression model was used to model depression in emerging adulthood as a function of drug use measurement controlling for other covariates and depression in adolescence. Our findings suggest that any conceptualization of drug use will produce equitable results and model fit statistics when examining externalizing problems. However, when investigating internalizing problems, such as depression, lower frequency drug use—and not high frequency—was more strongly associated with depression whereas experiencing high levels of drug use consequences—and not low levels of consequences—was associated with depression in emerging adulthood despite similar model fit values. Variation between drug use and the experience of drug use consequences may lead to misspecification of “at-risk” subgroups of drug users. Implications and future directions are discussed. PMID:24345310

  19. Do adolescent drug use consequences predict externalizing and internalizing problems in emerging adulthood as well as traditional drug use measures in a Hispanic sample?

    PubMed

    Grigsby, Timothy J; Forster, Myriam; Baezconde-Garbanati, Lourdes; Soto, Daniel W; Unger, Jennifer B

    2014-03-01

    The present study compares statistical models for three conceptualizations of drug use in 11th grade (past 30 day ever/never use, past 30 day frequency of drug use and past 30 day drug use consequences) with externalizing and internalizing problems in emerging adulthood when controlling for age, academic achievement and socioeconomic status in a Hispanic sample. Multivariate logistic regression models for the different drug use variables were compared when modeling weapon carrying, arrest, multiple lifetime sex partners, drug/alcohol use before sex and condom use in emerging adulthood. A multivariate linear regression model was used to model depression in emerging adulthood as a function of drug use measurement controlling for other covariates and depression in adolescence. Our findings suggest that any conceptualization of drug use will produce equitable results and model fit statistics when examining externalizing problems. However, when investigating internalizing problems, such as depression, lower frequency drug use-and not high frequency-was more strongly associated with depression whereas experiencing high levels of drug use consequences-and not low levels of consequences-was associated with depression in emerging adulthood despite similar model fit values. Variation between drug use and the experience of drug use consequences may lead to misspecification of "at-risk" subgroups of drug users. Implications and future directions are discussed. PMID:24345310

  20. A hopfield network learning method for bipartite subgraph problem.

    PubMed

    Wang, Rong Long; Tang, Zheng; Cao, Qi Ping

    2004-11-01

    In this paper, we present a gradient ascent learning method of the Hopfield neural network for bipartite subgraph problem. The method is intended to provide a near-optimum parallel algorithm for solving the bipartite subgraph problem. To do this we use the Hopfield neural network to get a near-maximum bipartite subgraph, and increase the energy by modifying weights in a gradient ascent direction of the energy to help the network escape from the state of the near-maximum bipartite subgraph to the state of the maximum bipartite subgraph or better one. A large number of instances are simulated to verify the proposed method with the simulation results showing that the solution quality is superior to that of best existing parallel algorithm. We also test the learning method on total coloring problem. The simulation results show that our method finds optimal solution in every test graph. PMID:15565773

  1. Questioning the method and utility of ranking drug harms in drug policy.

    PubMed

    Rolles, Stephen; Measham, Fiona

    2011-07-01

    In a 2010 Lancet paper Nutt et al. propose a model for evaluating and ranking drug harms, building on earlier work by incorporating multi criteria decision analysis. It is argued that problems arise in modelling drug harms using rankable single figure indices when determinants of harm reflect pharmacology translated through a complex prism of social and behavioural variables, in turn influenced by a range of policy environments. The delphic methodolgy used is highly vulnerable to subjective judgements and even the more robust measures, such as drug related death and dependence, can be understood as socially constructed. The failure of the model to dissaggregate drug use harms from those related to the policy environment is also highlighted. Beyond these methodological challenges the utility of single figure index harm rankings is questioned, specifically their role in increasingly redundant legal frameworks utilising a harm-based hierarchy of punitive sanctions. If analysis is to include the capacity to capture the complexity relating to drug using behaviours and environments; specific personal and social risks for particular using populations; and the broader socio-cultural context to contemporary intoxication, there will need to be acceptance that analysis of the various harm vectors must remain separate - the complexity of such analysis is not something that can or should be over generalised to suit political discourse or outdated legal frameworks. PMID:21652195

  2. [Applications of the Fragment Molecular Orbital Method in Drug Discovery].

    PubMed

    Ishikawa, Takeshi

    2016-01-01

      Recently, ab initio quantum mechanical calculations have been applied to large molecules, including biomolecular systems. The fragment molecular orbital (FMO) method is one of the most efficient approaches for the quantum mechanical investigation of such molecules. In the FMO method, dividing a target molecule into small fragments reduces computational effort. The clear definition of inter-fragment interaction energy (IFIE) as an expression of total energy is another valuable feature of the FMO method because it provides the ability to analyze interactions in biomolecules. Thus, the FMO method is expected to be useful for drug discovery. This study demonstrates applications of the FMO method related to drug discovery. First, IFIE, according to FMO calculations, was used in the optimization of drug candidates for the development of anti-prion compounds. The second example involved interaction analysis of the human immunodeficiency virus type 1 (HIV-1) protease and a drug compound that used a novel analytical method for dispersion interaction, i.e., fragment interaction analysis based on LMP2 (FILM). PMID:26725679

  3. Weaving a Formal Methods Education with Problem-Based Learning

    NASA Astrophysics Data System (ADS)

    Gibson, J. Paul

    The idea of weaving formal methods through computing (or software engineering) degrees is not a new one. However, there has been little success in developing and implementing such a curriculum. Formal methods continue to be taught as stand-alone modules and students, in general, fail to see how fundamental these methods are to the engineering of software. A major problem is one of motivation — how can the students be expected to enthusiastically embrace a challenging subject when the learning benefits, beyond passing an exam and achieving curriculum credits, are not clear? Problem-based learning has gradually moved from being an innovative pedagogique technique, commonly used to better-motivate students, to being widely adopted in the teaching of many different disciplines, including computer science and software engineering. Our experience shows that a good problem can be re-used throughout a student's academic life. In fact, the best computing problems can be used with children (young and old), undergraduates and postgraduates. In this paper we present a process for weaving formal methods through a University curriculum that is founded on the application of problem-based learning and a library of good software engineering problems, where students learn about formal methods without sitting a traditional formal methods module. The process of constructing good problems and integrating them into the curriculum is shown to be analagous to the process of engineering software. This approach is not intended to replace more traditional formal methods modules: it will better prepare students for such specialised modules and ensure that all students have an understanding and appreciation for formal methods even if they do not go on to specialise in them.

  4. Using improved serial blood sampling method of mice to study pharmacokinetics and drug-drug interaction.

    PubMed

    Watanabe, Ayahisa; Watari, Ryosuke; Ogawa, Keiko; Shimizu, Ryosuke; Tanaka, Yukari; Takai, Nozomi; Nezasa, Ken-ichi; Yamaguchi, Yoshitaka

    2015-03-01

    In pharmacokinetic evaluation of mice, using serial sampling methods rather than a terminal blood sampling method could reduce the number of animals needed and lead to more reliable data by excluding individual differences. In addition, using serial sampling methods can be valuable for evaluation of the drug-drug interaction (DDI) potential of drug candidates. In this study, we established an improved method for serially sampling the blood from one mouse by only one incision of the lateral tail vein, and investigated whether our method could be adapted to pharmacokinetic and DDI studies. After intravenous and oral administration of ibuprofen and fexofenadine (BCS class II and III), the plasma concentration and pharmacokinetic parameters were evaluated by our method and a terminal blood sampling method, with the result that both methods gave comparable results (ibuprofen: 63.8 ± 4.0% and 64.4%, fexofenadine: 6.5 ± 0.7% and 7.9%, respectively, in bioavailability). In addition, our method could be adapted to DDI study for cytochrome P450 and organic anion transporting polypeptide inhibition. These results demonstrate that our method can be useful for pharmacokinetic evaluation from the perspective of reliable data acquisition as well as easy handling and low stress to mice and improve the quality of pharmacokinetic and DDI studies. PMID:25452230

  5. Discomforting research: colliding moralities and looking for 'truth' in a study of parental drug problems.

    PubMed

    Barnard, Marina

    2005-01-01

    Research on socially-sensitive areas of human experience is particularly prone to raising thorny issues over the legitimacy and social consequences of the sociological gaze. In drugs research there is probably no more prickly a subject than the impact of a parents' problem drug use on the wellbeing and safety of children. This paper sets out to explore the processes and consequences of interpretation of narrative accounts provided by parents and their children through moving between substantive and methodological issues. Through consideration of the substantive data the paper draws away from the epistemological position that all accounts can be treated as equally valid. Instead it argues that whilst some objectified definitive 'truth' of the impact of parental problem drug use on children is not achievable, it is possible to say something of the processes by which drugs can take precedence over childcare concerns, even where some accounts are apparently contradictory. The logic of such an interpretation of a certain incompatibility between dependent drug use and childcare raises the issue of the capacity for research to harm those who form the focus of empirical research. PMID:15762949

  6. Drug-related problems (DRPs) identified from geriatric medication safety review clinics.

    PubMed

    Chan, Ding-Cheng; Chen, Jen-Hau; Kuo, Hsu-Ko; We, Chiung-Jung; Lu, I-Shu; Chiu, Lee-Shu; Wu, Shwu-Chong

    2012-01-01

    Drug-related problems (DRPs) were identified from baseline data of 193 Medication Safety Review Clinic (MSRC) patients. MSRCs enroll older adults (≥ 65 years) with either (1) prescriptions of ≥ 8 chronic medications (drugs prescribed for ≥ 28 days) or (2) a visit to ≥ 3 different physicians at the two participating hospitals in Taipei, Taiwan from August to October 2007. The Pharmaceutical Care Network Europe (PCNE) Classification Version 5.01 was used to report DRPs. Mean age was 76.2 ± 6.2 years and 53% of participants were male. Participants had, on average, 9.0 ± 2.6 chronic conditions and took 8.9 ± 3.1 chronic medications and 1.7 ± 1.8 dietary supplements. Eighty-seven percent had at least one DRP. Being older, having orthostatic hypotension and taking more chronic medications were associated with higher likelihood of having at least one DRP. For the 1713 medications and 331 diet supplements reviewed, 427 DRPs were found, 490 causes (1.1 ± 0.4 per problem) identified and 1067 interventions proposed (2.5 ± 0.6 per problem). The most common DRP category was "drug not taken/administered" (35%), and the most common offending drug category was cardiovascular agents (33%). Prevalence of DRPs was high among geriatric outpatients prescribed multiple medications. Careful medication review is needed in routine clinical practice to improve prescription quality. PMID:21353318

  7. Proposal of Evolutionary Simplex Method for Global Optimization Problem

    NASA Astrophysics Data System (ADS)

    Shimizu, Yoshiaki

    To make an agile decision in a rational manner, role of optimization engineering has been notified increasingly under diversified customer demand. With this point of view, in this paper, we have proposed a new evolutionary method serving as an optimization technique in the paradigm of optimization engineering. The developed method has prospects to solve globally various complicated problem appearing in real world applications. It is evolved from the conventional method known as Nelder and Mead’s Simplex method by virtue of idea borrowed from recent meta-heuristic method such as PSO. Mentioning an algorithm to handle linear inequality constraints effectively, we have validated effectiveness of the proposed method through comparison with other methods using several benchmark problems.

  8. [Levothyroxine and the problem of interchangeability of drugs with narrow therapeutic index].

    PubMed

    Ward, Laura Sterian

    2011-10-01

    The exchange of a prescribed drug by other similar, by generic products and even by custom products has become common practice in our country, often ignoring basic tenets of bioequivalence, interchangeability, stability and characteristics of the pharmaceutical compounds. In the case of drugs of narrow therapeutic index, such as levothyroxine, these problems are intensified, putting the effectiveness of treatment and patient health at serious risk. We review the pertinent legislation, emphasizing the characteristics of levothyroxine and adverse effects that limit the interchangeability of the compound. PMID:22147090

  9. Computational Method for Electrical Potential and Other Field Problems

    ERIC Educational Resources Information Center

    Hastings, David A.

    1975-01-01

    Proposes the finite differences relaxation method as a teaching tool in secondary and university level courses discussing electrical potential, temperature distribution in a region, and similar problems. Outlines the theory and operating procedures of the method, and discusses examples of teaching applications, including possible laboratory…

  10. Clinical pragmatism: a method of moral problem solving.

    PubMed

    Fins, Joseph J; Bacchetta, Matthew D; Miller, Franklin G

    1997-06-01

    This paper presents a method of moral problem solving in clinical practice that is inspired by the philosophy of John Dewey. This method, called "clinical pragmatism," integrates clinical and ethical decision making. Clinical pragmatism focuses on the interpersonal processes of assessment and consensus formation as well as the ethical analysis of relevant moral considerations. The steps in this method are delineated and then illustrated through a detailed case study. The implications of clinical pragmatism for the use of principles in moral problem solving are discussed. PMID:11654986

  11. A matrix product state method for solving combinatorial optimization problems

    NASA Astrophysics Data System (ADS)

    Pelton, S. S.; Chamon, C.; Mucciolo, E. R.

    2015-03-01

    We present a method based on a matrix product state representation to solve combinatorial optimization problems. All constraints are met by mapping Boolean gates into projection operators and applying operators sequentially. The method provides exact solutions with high success probability, even in the case of frustrated systems. The computational cost of the method is controlled by the maximum relative entropy of the system. Results of numerical simulations for several types of problems will be shown and discussed. NSF Grants CCF-1116590 and CCF-1117241.

  12. Solution of Boundary-Value Problems using Kantorovich Method

    NASA Astrophysics Data System (ADS)

    Gusev, A. A.; Hai, L. L.; Chuluunbaatar, O.; Vinitsky, S. I.; Derbov, V. L.

    2016-02-01

    We propose a computational scheme for solving the eigenvalue problem for an elliptic differential equation in a two-dimensional domain with Dirichlet boundary conditions. The solution is sought in the form of Kantorovich expansion over the basis functions of one of the independent variables with the second variable treated as a parameter. The basis functions are calculated as solutions of the parametric eigenvalue problem for an ordinary second-order differential equation. As a result, the initial problem is reduced to a boundary-value problem for a set of self-adjoint second-order differential equations for functions of the second independent variable. The discrete formulation of the problem is implemented using the finite element method with Hermite interpolation polynomials. The effciency of the calculation scheme is shown by benchmark calculations for a square membrane with a degenerate spectrum.

  13. Preconditioned Mixed Spectral Element Methods for Elasticity and Stokes Problems

    NASA Technical Reports Server (NTRS)

    Pavarino, Luca F.

    1996-01-01

    Preconditioned iterative methods for the indefinite systems obtained by discretizing the linear elasticity and Stokes problems with mixed spectral elements in three dimensions are introduced and analyzed. The resulting stiffness matrices have the structure of saddle point problems with a penalty term, which is associated with the Poisson ratio for elasticity problems or with stabilization techniques for Stokes problems. The main results of this paper show that the convergence rate of the resulting algorithms is independent of the penalty parameter, the number of spectral elements Nu and mildly dependent on the spectral degree eta via the inf-sup constant. The preconditioners proposed for the whole indefinite system are block-diagonal and block-triangular. Numerical experiments presented in the final section show that these algorithms are a practical and efficient strategy for the iterative solution of the indefinite problems arising from mixed spectral element discretizations of elliptic systems.

  14. Is There a Space-Based Technology Solution to Problems with Preclinical Drug Toxicity Testing?

    PubMed

    Hammond, Timothy; Allen, Patricia; Birdsall, Holly

    2016-07-01

    Even the finest state-of-the art preclinical drug testing, usually in primary hepatocytes, remains an imperfect science. Drugs continue to be withdrawn from the market due to unforeseen toxicity, side effects, and drug interactions. The space program may be able to provide a lifeline. Best known for rockets, space shuttles, astronauts and engineering, the space program has also delivered some serious medical science. Optimized suspension culture in NASA's specialized suspension culture devices, known as rotating wall vessels, uniquely maintains Phase I and Phase II drug metabolizing pathways in hepatocytes for weeks in cell culture. Previously prohibitively expensive, new materials and 3D printing techniques have the potential to make the NASA rotating wall vessel available inexpensively on an industrial scale. Here we address the tradeoffs inherent in the rotating wall vessel, limitations of alternative approaches for drug metabolism studies, and the market to be addressed. Better pre-clinical drug testing has the potential to significantly reduce the morbidity and mortality of one of the most common problems in modern medicine: adverse events related to pharmaceuticals. PMID:27183841

  15. Fenethylline (Captagon) Abuse - Local Problems from an Old Drug Become Universal.

    PubMed

    Katselou, Maria; Papoutsis, Ioannis; Nikolaou, Panagiota; Qammaz, Samir; Spiliopoulou, Chara; Athanaselis, Sotiris

    2016-08-01

    Fenethylline is a theophylline derivative of amphetamine having stimulant effects similar to those of other amphetamine-type derivatives. Fenethylline was used as medicament for hyperactivity disorders in children, narcolepsy and depression, but it has also been used as a drug of abuse under the common name of 'captagon'. Unlike other drugs of abuse, the clandestine synthesis of fenethylline is simple, using inexpensive laboratory instrumentation and raw materials legal to obtain. A review of all the existing knowledge of fenethylline is reported, concerning its chemistry, synthesis, pharmacology and toxicology, legislation, its prevalence and use as drug of abuse, as well as its analysis in biological or seized samples. Published or reported captagon-related cases and seizures are also presented. All the reviewed information was gathered through a detailed search of PubMed and the Internet. The primary drug market for fenethylline (as captagon) has traditionally been countries located on the Arabian Peninsula but also North Africa since 2013. In Arab countries, millions of captagon tablets are seized every year which represents one-third of global amphetamines seizures within a year. Furthermore, three of four patients treated for drug problems in Saudi Arabia are addicted to amphetamines, almost exclusively in the form of captagon. Significant information on fenethylline is provided for pharmacologists, toxicologists and forensic pathologists. Fenethylline, although old, has recently been introduced to the drug market, especially in Arab countries. Continuous community alertness is needed to tackle this current growing phenomenon. PMID:27004621

  16. The validation of analytical methods for drug substances and drug products in UK pharmaceutical laboratories.

    PubMed

    Clarke, G S

    1994-05-01

    Results of a survey on method validation of analytical procedures used in the testing of drug substances and finished products, of most major research based pharmaceutical companies with laboratories in the UK, are presented. The results indicate that although method validation shows an essential similarity in different laboratories (in particular, chromatographic assay methods are validated in a similar manner in most laboratories), there is much diversity in the detailed application of validation parameters. Testing procedures for drug substances are broadly similar to finished products. Many laboratories validate methods at clinical trial stage to the same extent and detail as at the marketing authorization application (MAA)/new drug application (NDA) submission stage, however, only a small minority of laboratories apply the same criteria to methodology at pre-clinical trial stage. Extensive details of method validation parameters are included in the summary tables of this survey, together with details of the median response given for the validation of the most extensively applied methods. These median response details could be useful in suggesting a harmonized approach to method validation as applied by UK pharmaceutical laboratories. These guidelines would extend beyond the recommendations made to date by regulatory authorities and pharmacopoeias in that minimum requirements for each method validation parameter, e.g. number of replicates, range and tolerance, could be harmonized, both between laboratories and also in Product Licence submissions. PMID:7948185

  17. TWO-GRID METHODS FOR MAXWELL EIGENVALUE PROBLEMS

    PubMed Central

    ZHOU, J.; HU, X.; ZHONG, L.; SHU, S.; CHEN, L.

    2015-01-01

    Two new two-grid algorithms are proposed for solving the Maxwell eigenvalue problem. The new methods are based on the two-grid methodology recently proposed by Xu and Zhou [Math. Comp., 70 (2001), pp. 17–25] and further developed by Hu and Cheng [Math. Comp., 80 (2011), pp. 1287–1301] for elliptic eigenvalue problems. The new two-grid schemes reduce the solution of the Maxwell eigenvalue problem on a fine grid to one linear indefinite Maxwell equation on the same fine grid and an original eigenvalue problem on a much coarser grid. The new schemes, therefore, save total computational cost. The error estimates reveals that the two-grid methods maintain asymptotically optimal accuracy, and the numerical experiments presented confirm the theoretical results. PMID:26190866

  18. Hybrid natural element method for large deformation elastoplasticity problems

    NASA Astrophysics Data System (ADS)

    Ma, Yong-Qi; Zhou, Yan-Kai

    2015-03-01

    We present the hybrid natural element method (HNEM) for two-dimensional elastoplastic large deformation problems. Sibson interpolation is adopted to construct the shape functions of nodal incremental displacements and incremental stresses. The incremental form of Hellinger-Reissner variational principle for elastoplastic large deformation problems is deduced to obtain the equation system. The total Lagrangian formulation is used to describe the discrete equation system. Compared with the natural element method (NEM), the HNEM has higher computational precision and efficiency in solving elastoplastic large deformation problems. Some numerical examples are selected to demonstrate the advantage of the HNEM for large deformation elastoplasticity problems. Project supported by the Natural Science Foundation of Shanghai, China (Grant No. 13ZR1415900).

  19. Perturbation method for probabilistic search for the traveling salesperson problem

    NASA Astrophysics Data System (ADS)

    Cohoon, James P.; Karro, John E.; Martin, Worthy N.; Niebel, William D.; Nagel, Klaus

    1998-10-01

    The Traveling Salesperson Problem (TSP), is an MP-complete combinatorial optimization problem of substantial importance in many scheduling applications. Here we show the viability of SPAN, a hybrid approach to solving the TSP that incorporates a perturbation method applied to a classic heuristic in the overall context of a probabilistic search control strategy. In particular, the heuristic for the TSP is based on the minimal spanning tree of the city locations, the perturbation method is a simple modification of the city locations, and the control strategy is a genetic algorithm (GA). The crucial concept here is that the perturbation of the problem allows variant solutions to be generated by the heuristic and applied to the original problem, thus providing the GA with capabilities for both exploration in its search process. We demonstrate that SPAN outperforms, with regard to solution quality, one of the best GA system reported in the literature.

  20. Solving inverse problems of identification type by optimal control methods

    SciTech Connect

    Lenhart, S.; Protopopescu, V.; Yong, J.

    1997-05-01

    Inverse problems of identification type for nonlinear equations are considered within the framework of optimal control theory. The rigorous solution of any particular problem depends on the functional setting, type of equation, and unknown quantity (or quantities) to be determined. Here we present only the general articulations of the formalism. Compared to classical regularization methods (e.g. Tikhonov coupled with optimization schemes), our approach presents several advantages, namely: (i) a systematic procedure to solve inverse problems of identification type; (ii) an explicit expression for the approximations of the solution; and (iii) a convenient numerical solution of these approximations. {copyright} {ital 1997 American Institute of Physics.}

  1. Solving inverse problems of identification type by optimal control methods

    SciTech Connect

    Lenhart, S.; Protopopescu, V.; Jiongmin Yong

    1997-06-01

    Inverse problems of identification type for nonlinear equations are considered within the framework of optimal control theory. The rigorous solution of any particular problem depends on the functional setting, type of equation, and unknown quantity (or quantities) to be determined. Here the authors present only the general articulations of the formalism. Compared to classical regularization methods (e.g. Tikhonov coupled with optimization schemes), their approach presents several advantages, namely: (i) a systematic procedure to solve inverse problems of identification type; (ii) an explicit expression for the approximations of the solution; and (iii) a convenient numerical solution of these approximations.

  2. Application of bifurcation methods to nonlinear flight dynamics problems

    NASA Astrophysics Data System (ADS)

    Goman, M. G.; Zagainov, G. I.; Khramtsovsky, A. V.

    Applications of global stability and bifurcational analysis methods are presented for different nonlinear flight dynamics problems, such as roll-coupling, stall, spin, etc. Based on the results for different real aircraft, F-4, F-14, F-15, High Incidence Research Model, (HIRM), the general methods developed by many authors are presented. The outline of basic concepts and methods from dynamcal system theory are also introduced.

  3. Development of a dynamically adaptive grid method for multidimensional problems

    NASA Astrophysics Data System (ADS)

    Holcomb, J. E.; Hindman, R. G.

    1984-06-01

    An approach to solution adaptive grid generation for use with finite difference techniques, previously demonstrated on model problems in one space dimension, has been extended to multidimensional problems. The method is based on the popular elliptic steady grid generators, but is 'dynamically' adaptive in the sense that a grid is maintained at all times satisfying the steady grid law driven by a solution-dependent source term. Testing has been carried out on Burgers' equation in one and two space dimensions. Results appear encouraging both for inviscid wave propagation cases and viscous boundary layer cases, suggesting that application to practical flow problems is now possible. In the course of the work, obstacles relating to grid correction, smoothing of the solution, and elliptic equation solvers have been largely overcome. Concern remains, however, about grid skewness, boundary layer resolution and the need for implicit integration methods. Also, the method in 3-D is expected to be very demanding of computer resources.

  4. Alchemical free energy methods for drug discovery: Progress and challenges

    PubMed Central

    Chodera, John D.; Mobley, David L.; Shirts, Michael R.; Dixon, Richard W.; Branson, Kim; Pande, Vijay S.

    2011-01-01

    Improved rational drug design methods are needed to lower the cost and increase the success rate of drug discovery and development. Alchemical binding free energy calculations, one potential tool for rational design, have progressed rapidly over the last decade, but still fall short of providing robust tools for pharmaceutical engineering. Recent studies, especially on model receptor systems, have clarified many of the challenges that must be overcome for robust predictions of binding affnity to be useful in rational design. In this review, inspired by a recent joint academic/industry meeting organized by the authors, we discuss these challenges and suggest a number of promising approaches for overcoming them. PMID:21349700

  5. In Vivo Methods for the Assessment of Topical Drug Bioavailability

    PubMed Central

    Herkenne, Christophe; Alberti, Ingo; Naik, Aarti; Kalia, Yogeshvar N.; Mathy, François-Xavier; Préat, Véronique

    2007-01-01

    This paper reviews some current methods for the in vivo assessment of local cutaneous bioavailability in humans after topical drug application. After an introduction discussing the importance of local drug bioavailability assessment and the limitations of model-based predictions, the focus turns to the relevance of experimental studies. The available techniques are then reviewed in detail, with particular emphasis on the tape stripping and microdialysis methodologies. Other less developed techniques, including the skin biopsy, suction blister, follicle removal and confocal Raman spectroscopy techniques are also described. PMID:17985216

  6. Integrated Force Method Solution to Indeterminate Structural Mechanics Problems

    NASA Technical Reports Server (NTRS)

    Patnaik, Surya N.; Hopkins, Dale A.; Halford, Gary R.

    2004-01-01

    Strength of materials problems have been classified into determinate and indeterminate problems. Determinate analysis primarily based on the equilibrium concept is well understood. Solutions of indeterminate problems required additional compatibility conditions, and its comprehension was not exclusive. A solution to indeterminate problem is generated by manipulating the equilibrium concept, either by rewriting in the displacement variables or through the cutting and closing gap technique of the redundant force method. Compatibility improvisation has made analysis cumbersome. The authors have researched and understood the compatibility theory. Solutions can be generated with equal emphasis on the equilibrium and compatibility concepts. This technique is called the Integrated Force Method (IFM). Forces are the primary unknowns of IFM. Displacements are back-calculated from forces. IFM equations are manipulated to obtain the Dual Integrated Force Method (IFMD). Displacement is the primary variable of IFMD and force is back-calculated. The subject is introduced through response variables: force, deformation, displacement; and underlying concepts: equilibrium equation, force deformation relation, deformation displacement relation, and compatibility condition. Mechanical load, temperature variation, and support settling are equally emphasized. The basic theory is discussed. A set of examples illustrate the new concepts. IFM and IFMD based finite element methods are introduced for simple problems.

  7. Parallel Monte Carlo Synthetic Acceleration methods for discrete transport problems

    NASA Astrophysics Data System (ADS)

    Slattery, Stuart R.

    This work researches and develops Monte Carlo Synthetic Acceleration (MCSA) methods as a new class of solution techniques for discrete neutron transport and fluid flow problems. Monte Carlo Synthetic Acceleration methods use a traditional Monte Carlo process to approximate the solution to the discrete problem as a means of accelerating traditional fixed-point methods. To apply these methods to neutronics and fluid flow and determine the feasibility of these methods on modern hardware, three complementary research and development exercises are performed. First, solutions to the SPN discretization of the linear Boltzmann neutron transport equation are obtained using MCSA with a difficult criticality calculation for a light water reactor fuel assembly used as the driving problem. To enable MCSA as a solution technique a group of modern preconditioning strategies are researched. MCSA when compared to conventional Krylov methods demonstrated improved iterative performance over GMRES by converging in fewer iterations when using the same preconditioning. Second, solutions to the compressible Navier-Stokes equations were obtained by developing the Forward-Automated Newton-MCSA (FANM) method for nonlinear systems based on Newton's method. Three difficult fluid benchmark problems in both convective and driven flow regimes were used to drive the research and development of the method. For 8 out of 12 benchmark cases, it was found that FANM had better iterative performance than the Newton-Krylov method by converging the nonlinear residual in fewer linear solver iterations with the same preconditioning. Third, a new domain decomposed algorithm to parallelize MCSA aimed at leveraging leadership-class computing facilities was developed by utilizing parallel strategies from the radiation transport community. The new algorithm utilizes the Multiple-Set Overlapping-Domain strategy in an attempt to reduce parallel overhead and add a natural element of replication to the algorithm. It

  8. In silico machine learning methods in drug development.

    PubMed

    Dobchev, Dimitar A; Pillai, Girinath G; Karelson, Mati

    2014-01-01

    Machine learning (ML) computational methods for predicting compounds with pharmacological activity, specific pharmacodynamic and ADMET (absorption, distribution, metabolism, excretion and toxicity) properties are being increasingly applied in drug discovery and evaluation. Recently, machine learning techniques such as artificial neural networks, support vector machines and genetic programming have been explored for predicting inhibitors, antagonists, blockers, agonists, activators and substrates of proteins related to specific therapeutic targets. These methods are particularly useful for screening compound libraries of diverse chemical structures, "noisy" and high-dimensional data to complement QSAR methods, and in cases of unavailable receptor 3D structure to complement structure-based methods. A variety of studies have demonstrated the potential of machine-learning methods for predicting compounds as potential drug candidates. The present review is intended to give an overview of the strategies and current progress in using machine learning methods for drug design and the potential of the respective model development tools. We also regard a number of applications of the machine learning algorithms based on common classes of diseases. PMID:25262800

  9. Emerging Computational Methods for the Rational Discovery of Allosteric Drugs

    PubMed Central

    2016-01-01

    Allosteric drug development holds promise for delivering medicines that are more selective and less toxic than those that target orthosteric sites. To date, the discovery of allosteric binding sites and lead compounds has been mostly serendipitous, achieved through high-throughput screening. Over the past decade, structural data has become more readily available for larger protein systems and more membrane protein classes (e.g., GPCRs and ion channels), which are common allosteric drug targets. In parallel, improved simulation methods now provide better atomistic understanding of the protein dynamics and cooperative motions that are critical to allosteric mechanisms. As a result of these advances, the field of predictive allosteric drug development is now on the cusp of a new era of rational structure-based computational methods. Here, we review algorithms that predict allosteric sites based on sequence data and molecular dynamics simulations, describe tools that assess the druggability of these pockets, and discuss how Markov state models and topology analyses provide insight into the relationship between protein dynamics and allosteric drug binding. In each section, we first provide an overview of the various method classes before describing relevant algorithms and software packages. PMID:27074285

  10. Emerging Computational Methods for the Rational Discovery of Allosteric Drugs.

    PubMed

    Wagner, Jeffrey R; Lee, Christopher T; Durrant, Jacob D; Malmstrom, Robert D; Feher, Victoria A; Amaro, Rommie E

    2016-06-01

    Allosteric drug development holds promise for delivering medicines that are more selective and less toxic than those that target orthosteric sites. To date, the discovery of allosteric binding sites and lead compounds has been mostly serendipitous, achieved through high-throughput screening. Over the past decade, structural data has become more readily available for larger protein systems and more membrane protein classes (e.g., GPCRs and ion channels), which are common allosteric drug targets. In parallel, improved simulation methods now provide better atomistic understanding of the protein dynamics and cooperative motions that are critical to allosteric mechanisms. As a result of these advances, the field of predictive allosteric drug development is now on the cusp of a new era of rational structure-based computational methods. Here, we review algorithms that predict allosteric sites based on sequence data and molecular dynamics simulations, describe tools that assess the druggability of these pockets, and discuss how Markov state models and topology analyses provide insight into the relationship between protein dynamics and allosteric drug binding. In each section, we first provide an overview of the various method classes before describing relevant algorithms and software packages. PMID:27074285

  11. The "rainbow" model: an attempt at a global approach to the drug problem.

    PubMed

    Pérez-Gómez, A; Jiménez-Suárez, S

    1993-04-01

    A global, tridimensional, and comprehensive model for the drug problem is presented. On a flat matrix with five components (growing, production, processing, traffic/distribution, and consumption) and seven dimensions (individual, family, restricted group, neighborhood, city/region, national, and international), six different perspectives are employed (psychobiological, social/political, economics, legal, historical/cultural, and geographical). Each psychoactive substance may be analyzed separately. PMID:8478153

  12. Nanobiological studies on drug design using molecular mechanic method

    PubMed Central

    Ghaheh, Hooria Seyedhosseini; Mousavi, Maryam; Araghi, Mahmood; Rasoolzadeh, Reza; Hosseini, Zahra

    2015-01-01

    Background: Influenza H1N1 is very important worldwide and point mutations that occur in the virus gene are a threat for the World Health Organization (WHO) and druggists, since they could make this virus resistant to the existing antibiotics. Influenza epidemics cause severe respiratory illness in 30 to 50 million people and kill 250,000 to 500,000 people worldwide every year. Nowadays, drug design is not done through trial and error because of its cost and waste of time; therefore bioinformatics studies is essential for designing drugs. Materials and Methods: This paper, infolds a study on binding site of Neuraminidase (NA) enzyme, (that is very important in drug design) in 310K temperature and different dielectrics, for the best drug design. Information of NA enzyme was extracted from Protein Data Bank (PDB) and National Center for Biotechnology Information (NCBI) websites. The new sequences of N1 were downloaded from the NCBI influenza virus sequence database. Drug binding sites were assimilated and homologized modeling using Argus lab 4.0, HyperChem 6.0 and Chem. D3 softwares. Their stability was assessed in different dielectrics and temperatures. Result: Measurements of potential energy (Kcal/mol) of binding sites of NA in different dielectrics and 310K temperature revealed that at time step size = 0 pSec drug binding sites have maximum energy level and at time step size = 100 pSec have maximum stability and minimum energy. Conclusions: Drug binding sites are more dependent on dielectric constants rather than on temperature and the optimum dielectric constant is 39/78. PMID:26605248

  13. Bioinformatics methods in drug repurposing for Alzheimer's disease.

    PubMed

    Siavelis, John C; Bourdakou, Marilena M; Athanasiadis, Emmanouil I; Spyrou, George M; Nikita, Konstantina S

    2016-03-01

    Alarming epidemiological features of Alzheimer's disease impose curative treatment rather than symptomatic relief. Drug repurposing, that is reappraisal of a substance's indications against other diseases, offers time, cost and efficiency benefits in drug development, especially when in silico techniques are used. In this study, we have used gene signatures, where up- and down-regulated gene lists summarize a cell's gene expression perturbation from a drug or disease. To cope with the inherent biological and computational noise, we used an integrative approach on five disease-related microarray data sets of hippocampal origin with three different methods of evaluating differential gene expression and four drug repurposing tools. We found a list of 27 potential anti-Alzheimer agents that were additionally processed with regard to molecular similarity, pathway/ontology enrichment and network analysis. Protein kinase C, histone deacetylase, glycogen synthase kinase 3 and arginase inhibitors appear consistently in the resultant drug list and may exert their pharmacologic action in an epidermal growth factor receptor-mediated subpathway of Alzheimer's disease. PMID:26197808

  14. Multigrid methods for bifurcation problems: The self adjoint case

    NASA Technical Reports Server (NTRS)

    Taasan, Shlomo

    1987-01-01

    This paper deals with multigrid methods for computational problems that arise in the theory of bifurcation and is restricted to the self adjoint case. The basic problem is to solve for arcs of solutions, a task that is done successfully with an arc length continuation method. Other important issues are, for example, detecting and locating singular points as part of the continuation process, switching branches at bifurcation points, etc. Multigrid methods have been applied to continuation problems. These methods work well at regular points and at limit points, while they may encounter difficulties in the vicinity of bifurcation points. A new continuation method that is very efficient also near bifurcation points is presented here. The other issues mentioned above are also treated very efficiently with appropriate multigrid algorithms. For example, it is shown that limit points and bifurcation points can be solved for directly by a multigrid algorithm. Moreover, the algorithms presented here solve the corresponding problems in just a few work units (about 10 or less), where a work unit is the work involved in one local relaxation on the finest grid.

  15. Problem-Solving Methods in Agent-Oriented Software Engineering

    NASA Astrophysics Data System (ADS)

    Bogg, Paul; Beydoun, Ghassan; Low, Graham

    Problem-solving methods (PSM) are abstract structures that describe specific reasoning processes employed to solve a set of similar problems. We envisage that off-the-shelf PSMs can assist in the development of agent-oriented solutions, not only as reusable and extensible components that software engineers employ for designing agent architecture solutions, but just as importantly as a set of runtime capabilities that agents themselves dynamically employ in order to solve problems. This chapter describes PSMs for agent-oriented software engineering (AOSE) that address interaction-dependent problem-solving such as negotiation or cooperation. An extension to an AOSE methodology MOBMAS is proposed whereby PSMs are integrated in the software development phases of MAS Organization Design, Internal Design, and Interaction Design. In this way, knowledge engineering drives the development of agent-oriented systems.

  16. Drug and alcohol abuse: The pattern and magnitude of the problem

    SciTech Connect

    Ajayi, P.A.

    1996-12-31

    In the last 12 months, many more cases of alcohol and drug (substance) abuse in the workplace were seen in the Escravos operations of Chevron Nigeria Limited than in previous years. This called the attention to the rising prevalence of drug and alcohol abuse in contradistinction to reports from similar organizations in other parts of the world. Chevron Nigeria has a written Drug and Alcohol Policy which has been dormant for some time because of the apparent rarity of the problem of substance abuse in the workplace. This Policy is being reviewed to broaden its scope and make it more effective. A total of 30 employees were tested for drugs and alcohol .6 exceeded the legal limits of Blood Alcohol Concentration (BAC) and 5 tested positive for drugs. Tests were mainly post-accident, reasonable cause and random. The common substances abused were alcohol, cannabis, cocaine and morphine in that order. The findings are compared with those of similar organizations in UK and USA. Efforts to control substance abuse in the workplace are being put into place.

  17. The iteration method for the Wahba problem solution

    NASA Astrophysics Data System (ADS)

    Kruzhilov, Ivan

    2014-12-01

    Wahba problem is the task of constrained optimization on SO(3). Solution of this task is vital for satellite attitude determination using star trackers. An iterative method having quadratic convergence is proposed. Each iteration of the proposed method is reduced to sequential rotation of the vectors and solving the system of linear algebraic equations. The method needs an initial approximation, which can be obtained by the TRIAD method. The quaternion form of the TRIAD method is given. One or two iterations are sufficient for finding the optimal solution using the proposed method. The primary advantage of the proposed method as compared with classical methods based on calculation of eigenvectors and singular decomposition is the simplicity of its implementation.

  18. Extrapolation techniques applied to matrix methods in neutron diffusion problems

    NASA Technical Reports Server (NTRS)

    Mccready, Robert R

    1956-01-01

    A general matrix method is developed for the solution of characteristic-value problems of the type arising in many physical applications. The scheme employed is essentially that of Gauss and Seidel with appropriate modifications needed to make it applicable to characteristic-value problems. An iterative procedure produces a sequence of estimates to the answer; and extrapolation techniques, based upon previous behavior of iterants, are utilized in speeding convergence. Theoretically sound limits are placed on the magnitude of the extrapolation that may be tolerated. This matrix method is applied to the problem of finding criticality and neutron fluxes in a nuclear reactor with control rods. The two-dimensional finite-difference approximation to the two-group neutron fluxes in a nuclear reactor with control rods. The two-dimensional finite-difference approximation to the two-group neutron-diffusion equations is treated. Results for this example are indicated.

  19. Problems of Mathematical Finance by Stochastic Control Methods

    NASA Astrophysics Data System (ADS)

    Stettner, Łukasz

    The purpose of this paper is to present main ideas of mathematics of finance using the stochastic control methods. There is an interplay between stochastic control and mathematics of finance. On the one hand stochastic control is a powerful tool to study financial problems. On the other hand financial applications have stimulated development in several research subareas of stochastic control in the last two decades. We start with pricing of financial derivatives and modeling of asset prices, studying the conditions for the absence of arbitrage. Then we consider pricing of defaultable contingent claims. Investments in bonds lead us to the term structure modeling problems. Special attention is devoted to historical static portfolio analysis called Markowitz theory. We also briefly sketch dynamic portfolio problems using viscosity solutions to Hamilton-Jacobi-Bellman equation, martingale-convex analysis method or stochastic maximum principle together with backward stochastic differential equation. Finally, long time portfolio analysis for both risk neutral and risk sensitive functionals is introduced.

  20. Characterization and Developmental History of Problem Solving Methods in Medicine

    PubMed Central

    Harbort, Robert A.

    1980-01-01

    The central thesis of this paper is the importance of the framework in which information is structured. It is technically important in the design of systems; it is also important in guaranteeing that systems are usable by clinicians. Progress in medical computing depends on our ability to develop a more quantitative understanding of the role of context in our choice of problem solving techniques. This in turn will help us to design more flexible and responsive computer systems. The paper contains an overview of some models of knowledge and problem solving methods, a characterization of modern diagnostic techniques, and a discussion of skill development in medical practice. Diagnostic techniques are examined in terms of how they are taught, what problem solving methods they use, and how they fit together into an overall theory of interpretation of the medical status of a patient.

  1. A decoupled monolithic projection method for natural convection problems

    NASA Astrophysics Data System (ADS)

    Pan, Xiaomin; Kim, Kyoungyoun; Lee, Changhoon; Choi, Jung-Il

    2016-06-01

    We propose an efficient monolithic numerical procedure based on a projection method for solving natural convection problems. In the present monolithic method, the buoyancy, linear diffusion, and nonlinear convection terms are implicitly advanced by applying the Crank-Nicolson scheme in time. To avoid an otherwise inevitable iterative procedure in solving the monolithic discretized system, we use a linearization of the nonlinear convection terms and approximate block lower-upper (LU) decompositions along with approximate factorization. Numerical simulations demonstrate that the proposed method is more stable and computationally efficient than other semi-implicit methods, preserving temporal second-order accuracy.

  2. Methodes entropiques appliquees au probleme inverse en magnetoencephalographie

    NASA Astrophysics Data System (ADS)

    Lapalme, Ervig

    2005-07-01

    This thesis is devoted to biomagnetic source localization using magnetoencephalography. This problem is known to have an infinite number of solutions. So methods are required to take into account anatomical and functional information on the solution. The work presented in this thesis uses the maximum entropy on the mean method to constrain the solution. This method originates from statistical mechanics and information theory. This thesis is divided into two main parts containing three chapters each. The first part reviews the magnetoencephalographic inverse problem: the theory needed to understand its context and the hypotheses for simplifying the problem. In the last chapter of this first part, the maximum entropy on the mean method is presented: its origins are explained and also how it is applied to our problem. The second part is the original work of this thesis presenting three articles; one of them already published and two others submitted for publication. In the first article, a biomagnetic source model is developed and applied in a theoretical con text but still demonstrating the efficiency of the method. In the second article, we go one step further towards a realistic modelization of the cerebral activation. The main priors are estimated using the magnetoencephalographic data. This method proved to be very efficient in realistic simulations. In the third article, the previous method is extended to deal with time signals thus exploiting the excellent time resolution offered by magnetoencephalography. Compared with our previous work, the temporal method is applied to real magnetoencephalographic data coming from a somatotopy experience and results agree with previous physiological knowledge about this kind of cognitive process.

  3. Discontinuous Galerkin Finite Element Method for Parabolic Problems

    NASA Technical Reports Server (NTRS)

    Kaneko, Hideaki; Bey, Kim S.; Hou, Gene J. W.

    2004-01-01

    In this paper, we develop a time and its corresponding spatial discretization scheme, based upon the assumption of a certain weak singularity of parallel ut(t) parallel Lz(omega) = parallel ut parallel2, for the discontinuous Galerkin finite element method for one-dimensional parabolic problems. Optimal convergence rates in both time and spatial variables are obtained. A discussion of automatic time-step control method is also included.

  4. MIMD massively parallel methods for engineering and science problems

    SciTech Connect

    Camp, W.J.; Plimpton, S.J.

    1993-08-01

    MIMD massively parallel computers promise unique power and flexibility for engineering and scientific simulations. In this paper we review the development of a number of software methods and algorithms for scientific and engineering problems which are helping to realize that promise. We discuss new domain decomposition, load balancing, data layout and communications methods applicable to simulations in a broad range of technical field including signal processing, multi-dimensional structural and fluid mechanics, materials science, and chemical and biological systems.

  5. Simplex method in problems of light-beam phase control.

    PubMed

    Chesnokov, S S; Davletshina, I V

    1995-12-20

    The possibility of the application of the simplex method to problems of wave-front control for light beams propagating in a nonlinear medium is investigated. A numerical analysis of simplex-method effectiveness in comparison with the gradient procedure of hill climbing is carried out. The regimes of stationary and nonstationary wind refraction are considered. The simplest optimization of the simplex size and the control basis is done. PMID:21068958

  6. Brief Intervention for Problem Drug Use in Safety-Net Primary Care Settings

    PubMed Central

    Roy-Byrne, Peter; Bumgardner, Kristin; Krupski, Antoinette; Dunn, Chris; Ries, Richard; Donovan, Dennis; West, Imara I.; Maynard, Charles; Atkins, David C.; Graves, Meredith C.; Joesch, Jutta M.; Zarkin, Gary A.

    2015-01-01

    IMPORTANCE Although brief intervention is effective for reducing problem alcohol use, few data exist on its effectiveness for reducing problem drug use, a common issue in disadvantaged populations seeking care in safety-net medical settings (hospitals and community health clinics serving low-income patients with limited or no insurance). OBJECTIVE To determine whether brief intervention improves drug use outcomes compared with enhanced care as usual. DESIGN, SETTING, AND PARTICIPANTS A randomized clinical trial with blinded assessments at baseline and at 3, 6, 9, and 12 months conducted in 7 safety-net primary care clinics in Washington State. Of 1621 eligible patients reporting any problem drug use in the past 90 days, 868 consented and were randomized between April 2009 and September 2012. Follow-up participation was more than 87% at all points. INTERVENTIONS Participants received a single brief intervention using motivational interviewing, a handout and list of substance abuse resources, and an attempted 10-minute telephone booster within 2 weeks (n = 435) or enhanced care as usual, which included a handout and list of substance abuse resources (n = 433). MAIN OUTCOMES AND MEASURES The primary outcomes were self-reported days of problem drug use in the past 30 days and Addiction Severity Index–Lite (ASI) Drug Use composite score. Secondary outcomes were admission to substance abuse treatment; ASI composite scores for medical, psychiatric, social, and legal domains; emergency department and inpatient hospital admissions, arrests, mortality, and human immunodeficiency virus risk behavior. RESULTS Mean days used of the most common problem drug at baseline were 14.40 (SD, 11.29) (brief intervention) and 13.25 (SD, 10.69) (enhanced care as usual); at 3 months postintervention, means were 11.87 (SD, 12.13) (brief intervention) and 9.84 (SD, 10.64) (enhanced care as usual) and not significantly different (difference in differences, β = 0.89 [95% CI, –0.49 to 2

  7. The trace minimization method for the symmetric generalized eigenvalue problem

    NASA Astrophysics Data System (ADS)

    Sameh, Ahmed; Tong, Zhanye

    2000-11-01

    In this paper, the trace minimization method for the generalized symmetric eigenvalue problems proposed by Sameh and Wisniewski [35] is reviewed. Convergence of an inexact trace minimization algorithm is established and a variant of the algorithm that uses expanding subspaces is introduced and compared with the block Jacobi-Davidson algorithm.

  8. Using the IDEAL Problem Solving Method in Groups.

    ERIC Educational Resources Information Center

    Smith, R. Scott

    In introductory psychology courses, the desire to cover content can conflict with the desire to acquaint students with psychological thinking processes. The IDEAL method is a group problem solving quiz technique which addresses both of these goals. In the process, instructors choose key concepts from a given reading and divide the class into…

  9. The lattice Boltzmann method and the problem of turbulence

    SciTech Connect

    Djenidi, L.

    2015-03-10

    This paper reports a brief review of numerical simulations of homogeneous isotopic turbulence (HIT) using the lattice Boltzmann method (LBM). The LBM results shows that the details of HIT are well captured and in agreement with existing data. This clearly indicates that the LBM is as good as current Navier-Stokes solvers and is very much adequate for investigating the problem of turbulence.

  10. Problems in Choosing Tools and Methods for Teaching Programming

    ERIC Educational Resources Information Center

    Vitkute-Adžgauskiene, Davia; Vidžiunas, Antanas

    2012-01-01

    The paper analyses the problems in selecting and integrating tools for delivering basic programming knowledge at the university level. Discussion and analysis of teaching the programming disciplines, the main principles of study programme design, requirements for teaching tools, methods and corresponding languages is presented, based on literature…

  11. Monitoring of air pollution by plants methods and problems

    SciTech Connect

    Steubing, L.; Jager, H.J.

    1985-01-01

    Ecosystem pollution is often discovered too late for preventive measure to be implemented. Papers include the topics of methods and problems of bioindication of air pollution. The participants discussed passive and active biological monitoring, including mapping of natural vegetation (lichens and mosses, for example) and plant exposure. Morphological and microscopical studies, chemical, physiological and biochemical investigations are presented.

  12. Stevens' Direct Scaling Methods and the Uniqueness Problem

    ERIC Educational Resources Information Center

    Augustin, Thomas

    2006-01-01

    Stevens postulated that we can use the responses of a participant in a ratio scaling experiment directly to construct a psychophysical function representing the participant's sensations. Although Stevens' methods of constructing measurement scales are widely used in the behavioral sciences, the problem of which scale type is appropriate to…

  13. Sensitivity analysis and approximation methods for general eigenvalue problems

    NASA Technical Reports Server (NTRS)

    Murthy, D. V.; Haftka, R. T.

    1986-01-01

    Optimization of dynamic systems involving complex non-hermitian matrices is often computationally expensive. Major contributors to the computational expense are the sensitivity analysis and reanalysis of a modified design. The present work seeks to alleviate this computational burden by identifying efficient sensitivity analysis and approximate reanalysis methods. For the algebraic eigenvalue problem involving non-hermitian matrices, algorithms for sensitivity analysis and approximate reanalysis are classified, compared and evaluated for efficiency and accuracy. Proper eigenvector normalization is discussed. An improved method for calculating derivatives of eigenvectors is proposed based on a more rational normalization condition and taking advantage of matrix sparsity. Important numerical aspects of this method are also discussed. To alleviate the problem of reanalysis, various approximation methods for eigenvalues are proposed and evaluated. Linear and quadratic approximations are based directly on the Taylor series. Several approximation methods are developed based on the generalized Rayleigh quotient for the eigenvalue problem. Approximation methods based on trace theorem give high accuracy without needing any derivatives. Operation counts for the computation of the approximations are given. General recommendations are made for the selection of appropriate approximation technique as a function of the matrix size, number of design variables, number of eigenvalues of interest and the number of design points at which approximation is sought.

  14. Toward better drug repositioning: prioritizing and integrating existing methods into efficient pipelines.

    PubMed

    Jin, Guangxu; Wong, Stephen T C

    2014-05-01

    Recycling old drugs, rescuing shelved drugs and extending patents' lives make drug repositioning an attractive form of drug discovery. Drug repositioning accounts for approximately 30% of the newly US Food and Drug Administration (FDA)-approved drugs and vaccines in recent years. The prevalence of drug-repositioning studies has resulted in a variety of innovative computational methods for the identification of new opportunities for the use of old drugs. Questions often arise from customizing or optimizing these methods into efficient drug-repositioning pipelines for alternative applications. It requires a comprehensive understanding of the available methods gained by evaluating both biological and pharmaceutical knowledge and the elucidated mechanism-of-action of drugs. Here, we provide guidance for prioritizing and integrating drug-repositioning methods for specific drug-repositioning pipelines. PMID:24239728

  15. Validation of Analytical Methods for Biomarkers Employed in Drug Development

    PubMed Central

    Chau, Cindy H.; Rixe, Olivier; McLeod, Howard; Figg, William D.

    2008-01-01

    The role of biomarkers in drug discovery and development has gained precedence over the years. As biomarkers become integrated into drug development and clinical trials, quality assurance and in particular assay validation becomes essential with the need to establish standardized guidelines for analytical methods used in biomarker measurements. New biomarkers can revolutionize both the development and use of therapeutics, but is contingent upon the establishment of a concrete validation process that addresses technology integration and method validation as well as regulatory pathways for efficient biomarker development. This perspective focuses on the general principles of the biomarker validation process with an emphasis on assay validation and the collaborative efforts undertaken by various sectors to promote the standardization of this procedure for efficient biomarker development. PMID:18829475

  16. An adaptive pseudo-spectral method for reaction diffusion problems

    NASA Technical Reports Server (NTRS)

    Bayliss, A.; Gottlieb, D.; Matkowsky, B. J.; Minkoff, M.

    1987-01-01

    The spectral interpolation error was considered for both the Chebyshev pseudo-spectral and Galerkin approximations. A family of functionals I sub r (u), with the property that the maximum norm of the error is bounded by I sub r (u)/J sub r, where r is an integer and J is the degree of the polynomial approximation, was developed. These functionals are used in the adaptive procedure whereby the problem is dynamically transformed to minimize I sub r (u). The number of collocation points is then chosen to maintain a prescribed error bound. The method is illustrated by various examples from combustion problems in one and two dimensions.

  17. Algebraic multigrid methods applied to problems in computational structural mechanics

    NASA Technical Reports Server (NTRS)

    Mccormick, Steve; Ruge, John

    1989-01-01

    The development of algebraic multigrid (AMG) methods and their application to certain problems in structural mechanics are described with emphasis on two- and three-dimensional linear elasticity equations and the 'jacket problems' (three-dimensional beam structures). Various possible extensions of AMG are also described. The basic idea of AMG is to develop the discretization sequence based on the target matrix and not the differential equation. Therefore, the matrix is analyzed for certain dependencies that permit the proper construction of coarser matrices and attendant transfer operators. In this manner, AMG appears to be adaptable to structural analysis applications.

  18. Changing to problem-oriented methods. Implementation in psychiatric institutions.

    PubMed

    Gaviria, B; Alvis, J; Zarour, N

    1976-08-01

    The so-called problem-oriented methods for organizing and recording clinical information offer many potential benefits to users in psychiatric institutions. Beyond the mechanical aspects of implementation, incorporating a problem-oriented approach into the practices of clinical teams entails conceptual and practical readjustments of considerable magnitude. Based on an 18-month study of eight psychiatric teams with diverse characteristics, the paper discusses rationales and priorities, as well as administrative and educational considerations in the conversion process. Such a process must be studied and understood in setting objectives and channeling resources, if outcomes are to match the expectations. PMID:1085344

  19. A time domain sampling method for inverse acoustic scattering problems

    NASA Astrophysics Data System (ADS)

    Guo, Yukun; Hömberg, Dietmar; Hu, Guanghui; Li, Jingzhi; Liu, Hongyu

    2016-06-01

    This work concerns the inverse scattering problems of imaging unknown/inaccessible scatterers by transient acoustic near-field measurements. Based on the analysis of the migration method, we propose efficient and effective sampling schemes for imaging small and extended scatterers from knowledge of time-dependent scattered data due to incident impulsive point sources. Though the inverse scattering problems are known to be nonlinear and ill-posed, the proposed imaging algorithms are totally "direct" involving only integral calculations on the measurement surface. Theoretical justifications are presented and numerical experiments are conducted to demonstrate the effectiveness and robustness of our methods. In particular, the proposed static imaging functionals enhance the performance of the total focusing method (TFM) and the dynamic imaging functionals show analogous behavior to the time reversal inversion but without solving time-dependent wave equations.

  20. The making of a public health problem: multi-drug resistant tuberculosis in India.

    PubMed

    Engel, Nora C

    2013-07-01

    This paper examines how actors construct the public problem of multi-drug resistant tuberculosis (MDR-TB) in India. MDR-TB has been framed by the World Health Organization as a pressing, global public health problem. The responses to MDR-TB are complicated as treatment takes longer and is more expensive than routine TB treatment. This is particularly problematic in countries, such as India, with high patient loads, a large and unregulated private sector, weak health systems and potentially high numbers of MDR-TB cases. This paper analyses how actors struggle for control over ownership, causal theories and political responsibility of the public problem of MDR-TB in India. It combines Gusfield's theory on the construction of public problems with insights from literature on the social construction of diseases and on medical social control. It highlights that there are flexible definitions of public problems, which are negotiated among actor groups and which shift over time. The Indian government has shifted its policy in recent years and acknowledged that MDR-TB needs to be dealt with within the TB programme. The study results reveal how the policy shift happened, why debates on the construction of MDR-TB as a public problem in India continue, and why actors with alternative theories than the government do not succeed in their lobbying efforts. Two main arguments are put forward. First, the construction of the public problem of MDR-TB in India is a social and political process. The need for representative data, international influence and politics define what is controllable. Second, the government seems to be anxious to control the definition of India's MDR-TB problem. This impedes an open, critical and transparent discussion on the definition of the public problem of MDR-TB, which is important in responding flexibly to emerging public health challenges. PMID:22865835

  1. Problems with NIOSH method 2520 for methyl bromide

    SciTech Connect

    Tharr, D.

    1994-03-01

    The National Institute for Occupational Safety and Health (NIOSH) publishes the NIOSH Manual of Analytical Methods (NMAM), a collection of analytical methods for characterizing exposures to environmental chemicals. When an industrial hygienist selects a method to monitor worker exposure, it is important to remember that not all the methods in the NMAM have undergone the same level of evaluation, as the following case demonstrates. As part of an industrywide study of the health effects resulting from methyl bromide exposure in structural and agricultural applicators, NIOSH researchers conducted industrial hygiene monitoring for methyl bromide in Florida during July 1990. NIOSH method 2520 was used. This method recommends use of two charcoal tubes (400 mg/100 mg) in series, desorption with carbon disulfide, and analysis by gas chromatography with a flame ionization detector. Sampling results from these surveys indicated a capacity problem. A project was then initiated to determine the reason for the methyl bromide breakthrough that occurred during industrial hygiene monitoring. While conducting research to define and solve this problem, several other problems were identified: reduced adsorption capacity caused by high humidity, difficulty in preparing standard solutions, sample instability, change in recovery with loading, and insufficiently low quantitation limit. The addition of a drying tube to the sampling train, as well as changes to the analytical technique, to the desorption solvent, and to the time till analysis, resulted in an improved method for methyl bromide. This case study demonstrates the importance of noting the conditions under which a method was evaluated and the benefit of testing method performance under conditions likely to exist at a field site. 5 refs.

  2. Projected discrete ordinates methods for numerical transport problems

    SciTech Connect

    Larsen, E.W.

    1985-01-01

    A class of Projected Discrete-Ordinates (PDO) methods is described for obtaining iterative solutions of discrete-ordinates problems with convergence rates comparable to those observed using Diffusion Synthetic Acceleration (DSA). The spatially discretized PDO solutions are generally not equal to the DSA solutions, but unlike DSA, which requires great care in the use of spatial discretizations to preserve stability, the PDO solutions remain stable and rapidly convergent with essentially arbitrary spatial discretizations. Numerical results are presented which illustrate the rapid convergence and the accuracy of solutions obtained using PDO methods with commonplace differencing methods.

  3. An analytic method for the inverse problem of MREPT

    NASA Astrophysics Data System (ADS)

    Palamodov, V.

    2016-03-01

    Magnetic resonance electric properties tomography (MREPT) is a medical imaging modality for visualizing the electrical tissue properties of the human body using radio-frequency magnetic fields. This method consists of reconstructing the admittivity distribution from the positive rotating component of the magnetic field. In the newest paper of Ammari et al (2015 Inverse Problems 31 105001) an approximate method of reconstruction of variable admittivity was proposed. In this paper a method for exact reconstruction of the admittivity from data of the positive rotating component of the field is given.

  4. 49 CFR 40.201 - What problems always cause a drug test to be cancelled and may result in a requirement for...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false What problems always cause a drug test to be... TESTING PROGRAMS Problems in Drug Tests § 40.201 What problems always cause a drug test to be cancelled... laboratory reports that any of the following problems have occurred. You must inform the DER that the...

  5. 49 CFR 40.201 - What problems always cause a drug test to be cancelled and may result in a requirement for...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false What problems always cause a drug test to be... TESTING PROGRAMS Problems in Drug Tests § 40.201 What problems always cause a drug test to be cancelled... laboratory reports that any of the following problems have occurred. You must inform the DER that the...

  6. Drug delivery formulations of ordered and nonordered mesoporous silica: comparison of three drug loading methods.

    PubMed

    Limnell, Tarja; Santos, Hélder A; Mäkilä, Ermei; Heikkilä, Teemu; Salonen, Jarno; Murzin, Dmitry Yu; Kumar, Narendra; Laaksonen, Timo; Peltonen, Leena; Hirvonen, Jouni

    2011-08-01

    A poorly soluble model drug, indomethacin (IMC), was loaded into two types of silica particles using three different loading methods. The loading efficiency and the extent/rate of drug release were evaluated. Widely used equipment in pharmaceutical laboratories, rotavapor and fluid bed, were used in the loading. The porous materials used were ordered mesoporous silica MCM-41 and nonordered silica gel Syloid 244 FP EU. The materials differ both in their pore properties and particle sizes. Tablets were successfully compressed from the IMC-loaded particles. Mechanical stability of the porous structures was studied with XRPD and nitrogen sorption after tableting and drug release was evaluated at pH 5.5 before and after tableting. The release of the poorly soluble IMC was faster from the Syloid than from the MCM-41, presumably due to the larger pore size and smaller particle size. Loading of IMC into the MCM-41 microparticles improved the drug dissolution, and blending the microparticles with pharmaceutical excipients improved the IMC release even further. The fast release was also maintained after tableting. Loading of IMC into the Syloid particles alone was sufficient to produce similar IMC release profiles, as in the case of MCM-41 with the excipients. PMID:21520084

  7. Poor Response Inhibition as a Predictor of Problem Drinking and Illicit Drug Use in Adolescents at Risk for Alcoholism and Other Substance Use Disorders

    ERIC Educational Resources Information Center

    Nigg, Joel T.; Wong, Maria M.; Martel, Michelle M.; Jester, Jennifer M.; Puttler, Leon I.; Glass, Jennifer M.; Adams, Kenneth M.; Fitzgerald, Hiram E.; Zucker, Robert A.

    2006-01-01

    Objective: To evaluate the predictive power of executive functions, in particular, response inhibition, in relation to alcohol-related problems and illicit drug use in adolescence. Method: A total of 498 children from 275 families from a longitudinal high-risk study completed executive function measures in early and late adolescence and lifetime…

  8. Links between Alcohol and Other Drug Problems and Maltreatment among Adolescent Girls: Perceived Discrimination, Ethnic Identity, and Ethnic Orientation as Moderators

    ERIC Educational Resources Information Center

    Gray, Calonie M. K.; Montgomery, Marilyn J.

    2012-01-01

    Objectives: This study examined the links between maltreatment, posttraumatic stress symptoms, ethnicity-specific factors (i.e., perceived discrimination, ethnic identity, and ethnic orientation), and alcohol and/or other drug (AOD) problems among adolescent girls. Methods: These relations were examined using archived data from a community sample…

  9. High order methods for elliptic problems in plasma physics

    NASA Astrophysics Data System (ADS)

    Pataki, Andras

    In this dissertation, we develop fast high order solvers for two elliptic problems in plasma physics. The first is the Grad-Shafranov equation, a nonlinear elliptic PDE that describes the magnetohydrodynamic equilibrium of three dimensional, axisymmetric plasmas. A high order solver is desirable to ensure the accurate evaluation of derivatives, required both for the computation of physical quantities and for studying perturbations near equilibrium. Using suitable scaling, we transform the problem from cylindrical coordinates to a nonlinear Poisson problem in Cartesian coordinates. We compute the conformal map from the original domain to the unit circle where we build a separation of variables based solver to obtain a high order, accurate solution. A fixed point or eigenvalue outer iteration is used to solve the nonlinear equation. Our second problem is the computation of the Coulomb collision operator that arises in kinetic models of plasmas. The collision operator can be written in terms of two Rosenbluth potentials obtained by solving a Poisson and a biharmonic problem in the velocity variables. For these PDEs we describe a new class of fast solvers in cylindrical coordinates with free-space radiation conditions. By combining integral equation methods in the radial variable with Fourier methods in the angular and z directions, we show that high-order accuracy can be achieved in both the solution and its derivatives. A weak singularity arises in the Fourier transform with respect to z that is handled with special purpose quadratures. Such solvers are ideally suited to the Rosenbluth potentials, since the collision operator is expressed in terms of up to fourth derivatives of the potentials, placing stringent demands on the computational order. Also, since axisymmetry is generally assumed in the velocity variables, the use of cylindrical coordinates reduces the three dimensional problem to a two dimensional computation.

  10. Treatment needs and experiences of Australian women with alcohol and other drug problems.

    PubMed

    Swift, W; Copeland, J

    1996-03-01

    Two hundred and sixty-seven women were interviewed as part of a national survey examining the treatment needs and experiences of Australian women who had received assistance for their alcohol and other drug problems. The majority of women had previously received assistance for their substance use, and of these most had left alcohol and other drug treatment programs before completion. While the women cited a number of ways in which they were helped by such services, several areas were identified by the women as important and amenable to improvement. Among the service issues raised were access, models of service delivery, service structure and staffing, physical environment, physical and psychological safety and the handling of issues such as health status and sexual assault. PMID:8861399