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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. 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

  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. 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

  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. 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

  2. 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

  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 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

  9. 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

  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. [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

  2. 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

  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. 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)

  6. [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…

  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. 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

  13. 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

  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. 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.

  20. 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.

  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. 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.

  8. 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.

  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. 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

  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. 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.

  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. 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

  15. 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

  16. 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).

  17. 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.

  18. 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

  19. 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

  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

    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

  10. 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

  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. 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.

  19. 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.

  20. 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.

  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. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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…

  10. 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…

  11. 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…

  12. 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.

  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. 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

  17. 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.

  18. 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.

  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

  11. Immersed boundary conditions method for computational fluid dynamics problems

    NASA Astrophysics Data System (ADS)

    Husain, Syed Zahid

    This dissertation presents implicit spectrally-accurate algorithms based on the concept of immersed boundary conditions (IBC) for solving a range of computational fluid dynamics (CFD) problems where the physical domains involve boundary irregularities. Both fixed and moving irregularities are considered with particular emphasis placed on the two-dimensional moving boundary problems. The physical model problems considered are comprised of the Laplace operator, the biharmonic operator and the Navier-Stokes equations, and thus cover the most commonly encountered types of operators in CFD analyses. The IBC algorithm uses a fixed and regular computational domain with flow domain immersed inside the computational domain. Boundary conditions along the edges of the time-dependent flow domain enter the algorithm in the form of internal constraints. Spectral spatial discretization for two-dimensional problems is based on Fourier expansions in the stream-wise direction and Chebyshev expansions in the normal-to-the-wall direction. Up to fourth-order implicit temporal discretization methods have been implemented. The IBC algorithm is shown to deliver the theoretically predicted accuracy in both time and space. Construction of the boundary constraints in the IBC algorithm provides degrees of freedom in excess of that required to formulate a closed system of algebraic equations. The 'classical IBC formulation' works by retaining number boundary constraints that are just sufficient to form a closed system of equations. The use of additional boundary constraints leads to the 'over-determined formulation' of the IBC algorithm. Over-determined systems are explored in order to improve the accuracy of the IBC method and to expand its applicability to more extreme geometries. Standard direct over-determined solvers based on evaluation of pseudo-inverses of the complete coefficient matrices have been tested on three model problems, namely, the Laplace equation, the biharmonic equation

  12. A variational Bayesian method to inverse problems with impulsive noise

    NASA Astrophysics Data System (ADS)

    Jin, Bangti

    2012-01-01

    We propose a novel numerical method for solving inverse problems subject to impulsive noises which possibly contain a large number of outliers. The approach is of Bayesian type, and it exploits a heavy-tailed t distribution for data noise to achieve robustness with respect to outliers. A hierarchical model with all hyper-parameters automatically determined from the given data is described. An algorithm of variational type by minimizing the Kullback-Leibler divergence between the true posteriori distribution and a separable approximation is developed. The numerical method is illustrated on several one- and two-dimensional linear and nonlinear inverse problems arising from heat conduction, including estimating boundary temperature, heat flux and heat transfer coefficient. The results show its robustness to outliers and the fast and steady convergence of the algorithm.

  13. Fully converged iterative method for coupled channel problems

    NASA Astrophysics Data System (ADS)

    Shu, Di; Simbotin, I.; Côté, R.

    2016-05-01

    We implemented a numerical method using a distorted-wave perturbative approach for coupled-channel scattering problems. Our new method provides a way to avoid costly computations for the propagation of the full solutions in coupled-channel problems to large distances for slowly vanishing couplings. Thus, instead of dealing with large matrices, all computations are performed in a channel by channel fashion. The distorted wavefunction for each channel is initialized with the appropriate solution (which includes the diagonal element of the coupling potential matrix). We then solve single-channel inhomogeneous radial equations which contain the (off-diagonal) couplings as a perturbation, and we iterate until desired accuracy is achieved. We tested for stability by continuing to iterate even after convergence has been achieved, e.g., for a total of 75 iterations. Partial support from the US Army Research Office (ARO-MURI W911NF-14-1-0378), and from NSF (Grant No. PHY-1415560).

  14. Adaptive domain decomposition methods for advection-diffusion problems

    SciTech Connect

    Carlenzoli, C.; Quarteroni, A.

    1995-12-31

    Domain decomposition methods can perform poorly on advection-diffusion equations if diffusion is dominated by advection. Indeed, the hyperpolic part of the equations could affect the behavior of iterative schemes among subdomains slowing down dramatically their rate of convergence. Taking into account the direction of the characteristic lines we introduce suitable adaptive algorithms which are stable with respect to the magnitude of the convective field in the equations and very effective on bear boundary value problems.

  15. The Newton Modified Barrier Method for QP Problems

    NASA Technical Reports Server (NTRS)

    Melman, A.; Polyak, R.

    1996-01-01

    The Modified Barrier Functions (MBF) have elements of both Classical Lagrangians (CL) and Classical Barrier Functions (CBF). The MBF methods find an unconstrained minimizer of some smooth barrier function in primal space and then update the Lagrange multipliers, while the barrier parameter either remains fixed or can be updated at each step. The numerical realization of the MBF method leads to the Newton MBF method, where the primal minimizer is found by using Newton's method. This minimizer is then used to update the Lagrange multipliers. In this paper, we examine the Newton MBF method for the Quadratic Programming (QP) problem. It will be shown that under standard second-order optimality conditions, there is a ball around the primal solution and a cut cone in the dual space such that for a set of Lagrange multipliers in this cut cone, the method converges quadratically to the primal minimizer from any point in the aforementioned ball, and continues to do so after each Lagrange multiplier update. The Lagrange multipliers remain within the cut cone and converge linearly to their optimal values. Any point in this ball will be called a "hot start". Starting at such a "hot start", at most Omicron(1n 1n epsilon(exp -1)) Newton steps are sufficient to perform the primal minimization which is necessary for the Lagrange multiplier update. Here, epsilon > 0 is the desired accuracy. Because of the linear convergence of the Lagrange multipliers, this means that only Omicron(1n epsilon(exp -1))omicron(ln 1n epsilon(exp-1)) Newton steps are required to reach an epsilon-approximation to the solution from any "hot start". In order to reach the "hot start", one has to perform Omicron(square root(m) 1n C) Newton steps, where m characterizes the size of the problem and C > 0 is the condition number of the QP problem. This condition number will be characterized explicitly in terms of key parameters of the QP problem, which in turn depend on the input data and the size of the problem.

  16. On the Application of the Energy Method to Stability Problems

    NASA Technical Reports Server (NTRS)

    Marguerre, Karl

    1947-01-01

    Since stability problems have come into the field of vision of engineers, energy methods have proved to be one of the most powerful aids in mastering them. For finding the especially interesting critical loads special procedures have evolved that depart somewhat from those customary in the usual elasticity theory. A clarification of the connections seemed desirable,especially with regard to the post-critical region, for the treatment of which these special methods are not suited as they are. The present investigation discusses this question-complex (made important by shell construction in aircraft) especially in the classical example of the Euler strut, because in this case - since the basic features are not hidden by difficulties of a mathematical nature - the problem is especially clear. The present treatment differs from that appearing in the Z.f.a.M.M. (1938) under the title "Uber die Behandlung von Stabilittatsproblemen mit Hilfe der energetischen Methode" in that, in order to work out the basic ideas still more clearly,it dispenses with the investigation of behavior at large deflections and of the elastic foundation;in its place the present version gives an elaboration of the 6th section and (in its 7 th and 8th secs.)a new example that shows the applicability of the general criterion to a stability problem that differs from that of Euler in many respects.

  17. Solving ODE Initial Value Problems With Implicit Taylor Series Methods

    NASA Technical Reports Server (NTRS)

    Scott, James R.

    2000-01-01

    In this paper we introduce a new class of numerical methods for integrating ODE initial value problems. Specifically, we propose an extension of the Taylor series method which significantly improves its accuracy and stability while also increasing its range of applicability. To advance the solution from t (sub n) to t (sub n+1), we expand a series about the intermediate point t (sub n+mu):=t (sub n) + mu h, where h is the stepsize and mu is an arbitrary parameter called an expansion coefficient. We show that, in general, a Taylor series of degree k has exactly k expansion coefficients which raise its order of accuracy. The accuracy is raised by one order if k is odd, and by two orders if k is even. In addition, if k is three or greater, local extrapolation can be used to raise the accuracy two additional orders. We also examine stability for the problem y'= lambda y, Re (lambda) less than 0, and identify several A-stable schemes. Numerical results are presented for both fixed and variable stepsizes. It is shown that implicit Taylor series methods provide an effective integration tool for most problems, including stiff systems and ODE's with a singular point.

  18. Structure-based virtual screening for drug discovery: a problem-centric review.

    PubMed

    Cheng, Tiejun; Li, Qingliang; Zhou, Zhigang; Wang, Yanli; Bryant, Stephen H

    2012-03-01

    Structure-based virtual screening (SBVS) has been widely applied in early-stage drug discovery. From a problem-centric perspective, we reviewed the recent advances and applications in SBVS with a special focus on docking-based virtual screening. We emphasized the researchers' practical efforts in real projects by understanding the ligand-target binding interactions as a premise. We also highlighted the recent progress in developing target-biased scoring functions by optimizing current generic scoring functions toward certain target classes, as well as in developing novel ones by means of machine learning techniques. PMID:22281989

  19. Methods for calculating conjugate problems of heat transfer

    NASA Astrophysics Data System (ADS)

    Kalinin, E. K.; Dreitser, G. A.; Kostiuk, V. V.; Berlin, I. I.

    Methods are examined for calculating various conjugate problems of heat transfer in channels and closed vessels in cases of single-phase and two-phase flow in steady and unsteady conditions. The single-phase-flow studies involve the investigation of gaseous and liquid heat-carriers in pipes, annular and plane channels, and pipe bundles in cases of cooling and heating. General relationships are presented for heat transfer in cases of film, transition, and nucleate boiling, as well as for boiling crises. Attention is given to methods for analyzing the filling and cooling of conduits and tanks by cryogenic liquids; and ways to intensify heat transfer in these conditions are examined.

  20. Two chromatographic methods for the determination of some antimigraine drugs.

    PubMed

    El-Bagary, Ramzia I; Mohammed, Nashwah G; Nasr, Heba A

    2012-01-01

    Two stability indicating chromatographic methods were proposed for the determination of almotriptan, eletriptan, and rizatriptan, in presence of their acid degradation products. The first method is a quantitative densitometric thin layer chromatography. The developing systems were; acetonitrile: methanol: dichloromethane: ammonia (10:6:3:1 v/v), ethyl acetate: methanol: ammonia (15:4:1 v/v), and methanol: acetonitrile: ammonia (9:4:1 v/v) for almotriptan, eletriptan and rizatriptan respectively. The TLC plates were scanned at 235 nm. Linear relationships were obtained over concentration ranges (5-50 μg/spot) for almotriptan and rizatriptan, and (5-60 μg/spot) for eletriptan. The second method based on the separation and determination of the studied drugs, using RP-HPLC technique. The separation was achieved on C18 Hypersil column, elution was carried out using phosphate buffer pH 3: methanol: acetonitrile (2: 1:1 v/v) at flow rate 2 mL/min and UV detection at 235 nm. Linear relationships were obtained over concentration ranges (10-200 μg/mL) for almotriptan and eletriptan, and (10-180 μg/mL) for rizatriptan. The chromatographic methods were successfully applied for the determination of each of the studied drugs in pure form, tablet form, and in laboratory prepared mixtures with their acid degradation products. PMID:22654488

  1. Two Chromatographic Methods for the Determination of Some Antimigraine Drugs

    PubMed Central

    El-Bagary, Ramzia I.; Mohammed, Nashwah G.; Nasr, Heba A.

    2012-01-01

    Two stability indicating chromatographic methods were proposed for the determination of almotriptan, eletriptan, and rizatriptan, in presence of their acid degradation products. The first method is a quantitative densitometric thin layer chromatography. The developing systems were; acetonitrile: methanol: dichloromethane: ammonia (10:6:3:1 v/v), ethyl acetate: methanol: ammonia (15:4:1 v/v), and methanol: acetonitrile: ammonia (9:4:1 v/v) for almotriptan, eletriptan and rizatriptan respectively. The TLC plates were scanned at 235 nm. Linear relationships were obtained over concentration ranges (5–50 μg/spot) for almotriptan and rizatriptan, and (5–60 μg/spot) for eletriptan. The second method based on the separation and determination of the studied drugs, using RP-HPLC technique. The separation was achieved on C18 Hypersil column, elution was carried out using phosphate buffer pH 3: methanol: acetonitrile (2: 1:1 v/v) at flow rate 2 mL/min and UV detection at 235 nm. Linear relationships were obtained over concentration ranges (10–200 μg/mL) for almotriptan and eletriptan, and (10–180 μg/mL) for rizatriptan. The chromatographic methods were successfully applied for the determination of each of the studied drugs in pure form, tablet form, and in laboratory prepared mixtures with their acid degradation products. PMID:22654488

  2. Development and validation of the Slovenian drug-related problem classification system based on the PCNE classification V 6.2.

    PubMed

    Horvat, Nejc; Kos, Mitja

    2016-08-01

    Background Classifying drug-related problems increases pharmacists' awareness of patients' drug-related needs and supports the development of counselling skills through increased awareness of the nature and frequency of drug-related problems. No standardised classification system was used in daily pharmacy practice in Slovenia. Objective To translate, upgrade and validate the Pharmaceutical Care Network Europe (PCNE) classification V 6.2 for use in Slovenian community pharmacies. Setting Expert panel meetings at the Faculty of Pharmacy and home-based classification validation. Methods The PCNE classification V 6.2 was translated to Slovenian language by forward-backward translation procedure. An expert panel consisting of nine practicing pharmacists upgraded the content of the translated version. Thirty-one community pharmacists validated this version with the PCNE set of 18 patient cases by coding problems, risk factors and interventions they believed were present in each case. The expert panel discussed the results and upgraded the classification accordingly. Afterwards, 33 community pharmacists validated the upgraded version with a set of 40 actual Slovenian pharmacy patient cases. Based on the results, the expert panel formed a final version of the classification. Main outcome measure Coding consistency between community pharmacists. Results The expert panel performed some major modifications to the PCNE classification V 6.2: the potential problem was added as a sub domain to problems domain; the term adverse drug event was used instead of adverse drug reaction; the causes domain was renamed to risk factors and its sub domains were organized into prescribing, dispensing and use of drugs; dispensing errors were specified; use of drugs was organized into intentional and unintentional use of drugs; the sub domains in the interventions domain were divided according to the communication and agreement with the prescriber. The average coding consistencies in the first

  3. A survey of electronic drug information resources and identification of problems associated with the differing vocabularies used to key them.

    PubMed Central

    Gnassi, J. A.; Barnett, G. O.

    1993-01-01

    Drug information resources are increasingly becoming electronically available. They differ in scope, granularity, and purpose. These considerations have shaped the selection of dissimilar drug name keys, complicating access. An abbreviated and simplified historical context of the development of official controlled vocabularies and their relationships is followed by a review of the kinds of information available in several electronic drug information resources. The key vocabularies used are discussed with examples. Problems using the differing terms of the resource vocabularies are identified. PMID:8130551

  4. The Committee on Problems of Drug Dependence: a legacy of the National Academy of Sciences. A historical account.

    PubMed

    May, E L; Jacobson, A E

    1989-06-01

    The history of The Committee on Problems of Drug Dependence is traced from its beginning (1929) as The Committee on Drug Addiction to 1989, its sixtieth anniversary. A brief account of the etiology of The Committee from The Bureau of Social Hygiene, established in New York City by John D. Rockefeller, Jr. in 1913 is also given. PMID:2666074

  5. On path-following methods for structural failure problems

    NASA Astrophysics Data System (ADS)

    Stanić, Andjelka; Brank, Boštjan; Korelc, Jože

    2016-08-01

    We revisit the consistently linearized path-following method that can be applied in the nonlinear finite element analysis of solids and structures in order to compute a solution path. Within this framework, two constraint equations are considered: a quadratic one (that includes as special cases popular spherical and cylindrical forms of constraint equation), and another one that constrains only one degree-of-freedom (DOF), the critical DOF. In both cases, the constrained DOFs may vary from one solution increment to another. The former constraint equation is successful in analysing geometrically nonlinear and/or standard inelastic problems with snap-throughs, snap-backs and bifurcation points. However, it cannot handle problems with the material softening that are computed e.g. by the embedded-discontinuity finite elements. This kind of problems can be solved by using the latter constraint equation. The plusses and minuses of the both presented constraint equations are discussed and illustrated on a set of numerical examples. Some of the examples also include direct computation of critical points and branch switching. The direct computation of the critical points is performed in the framework of the path-following method by using yet another constraint function, which is eigenvector-free and suited to detect critical points.

  6. [Alcohol and drugs in Central Europe--problems and possible solutions].

    PubMed

    Nespor, K; Cs emy, L

    1994-08-22

    The high alcohol consumption and increasing abuse of other addictive inducing substances in Central Europe calls for broadley conceived preventive programmes and cheap and widely applicable therapeutic strategies (early treatment at the first contact level, self-help manuals, self-aid organizations). Social instability along with greater availability of alcohol and drugs create a dangerous combination. In addition to strategies of stress prevention at the societal level also strategy at the individual level is important (e.g. relaxation training, yoga, psychotherapy). It is also important to change the "image" of western society and commercial interests of those who make profits on alcohol and drugs should be under control and advertising should be greatly restricted if not prohibited. Prevention of problems caused by alcohol and drugs in particular in youths must be combined and really effective strategies should be used such as peer programmes. The authors mention also their own preventive programme FIT IN and print materials oriented specifically on certain population groups. PMID:7923324

  7. WEAK GALERKIN METHODS FOR SECOND ORDER ELLIPTIC INTERFACE PROBLEMS.

    PubMed

    Mu, Lin; Wang, Junping; Wei, Guowei; Ye, Xiu; Zhao, Shan

    2013-10-01

    Weak Galerkin methods refer to general finite element methods for partial differential equations (PDEs) in which differential operators are approximated by their weak forms as distributions. Such weak forms give rise to desirable flexibilities in enforcing boundary and interface conditions. A weak Galerkin finite element method (WG-FEM) is developed in this paper for solving elliptic PDEs with discontinuous coefficients and interfaces. Theoretically, it is proved that high order numerical schemes can be designed by using the WG-FEM with polynomials of high order on each element. Extensive numerical experiments have been carried to validate the WG-FEM for solving second order elliptic interface problems. High order of convergence is numerically confirmed in both L 2 and L ∞ norms for the piecewise linear WG-FEM. Special attention is paid to solve many interface problems, in which the solution possesses a certain singularity due to the nonsmoothness of the interface. A challenge in research is to design nearly second order numerical methods that work well for problems with low regularity in the solution. The best known numerical scheme in the literature is of order [Formula: see text] to [Formula: see text] for the solution itself in L ∞ norm. It is demonstrated that the WG-FEM of the lowest order, i.e., the piecewise constant WG-FEM, is capable of delivering numerical approximations that are of order [Formula: see text] to [Formula: see text] in the L ∞ norm for C (1) or Lipschitz continuous interfaces associated with a C (1) or H (2) continuous solution. PMID:24072935

  8. Discrete Element Method Simulation of Nonlinear Viscoelastic Stress Wave Problems

    NASA Astrophysics Data System (ADS)

    Tang, Zhiping; Horie, Y.; Wang, Wenqiang

    2002-07-01

    A DEM(Discrete Element Method) simulation of nonlinear viscoelastic stress wave problems is carried out. The interaction forces among elements are described using a model in which neighbor elements are linked by a nonlinear spring and a certain number of Maxwell components in parallel. By making use of exponential relaxation moduli, it is shown that numerical computation of the convolution integral does not require storing and repeatedly calculating strain history, so that the computational cost is dramatically reduced. To validate the viscoelastic DM2 code1, stress wave propagation in a Maxwell rod with one end subjected to a constant stress loading is simulated. Results excellently fit those from the characteristics calculation. The code is then used to investigate the problem of meso-scale damage in a plastic-bonded explosive under shock loading. Results not only show "compression damage", but also reveal a complex damage evolution. They demonstrate a unique capability of DEM in modeling heterogeneous materials.

  9. Discrete Element Method Simulation of Nonlinear Viscoelastic Stress Wave Problems

    NASA Astrophysics Data System (ADS)

    Wang, Wenqiang; Tang, Zhiping; Horie, Y.

    2002-07-01

    A DEM(Discrete Element Method) simulation of nonlinear viscoelastic stress wave problems is carried out. The interaction forces among elements are described using a model in which neighbor elements are linked by a nonlinear spring and a certain number of Maxwell components in parallel. By making use of exponential relaxation moduli, it is shown that numerical computation of the convolution integral does not require storing and repeatedly calculating strain history, so that the computational cost is dramatically reduced. To validate the viscoelastic DM2 code[1], stress wave propagation in a Maxwell rod with one end subjected to a constant stress loading is simulated. Results excellently fit those from the characteristics calculation. The code is then used to investigate the problem of meso-scale damage in a plastic-bonded explosive under shock loading. Results not only show "compression damage", but also reveal a complex damage evolution. They demonstrate a unique capability of DEM in modeling heterogeneous materials.

  10. Variance reduction methods applied to deep-penetration problems

    SciTech Connect

    Cramer, S.N.

    1984-01-01

    All deep-penetration Monte Carlo calculations require variance reduction methods. Before beginning with a detailed approach to these methods, several general comments concerning deep-penetration calculations by Monte Carlo, the associated variance reduction, and the similarities and differences of these with regard to non-deep-penetration problems will be addressed. The experienced practitioner of Monte Carlo methods will easily find exceptions to any of these generalities, but it is felt that these comments will aid the novice in understanding some of the basic ideas and nomenclature. Also, from a practical point of view, the discussions and developments presented are oriented toward use of the computer codes which are presented in segments of this Monte Carlo course.

  11. Multiple-drug resistant enterococci: the nature of the problem and an agenda for the future.

    PubMed Central

    Huycke, M. M.; Sahm, D. F.; Gilmore, M. S.

    1998-01-01

    Enterococci, leading causes of nosocomial bacteremia, surgical wound infection, and urinary tract infection, are becoming resistant to many and sometimes all standard therapies. New rapid surveillance methods are highlighting the importance of examining enterococcal isolates at the species level. Most enterococcal infections are caused by Enterococcus faecalis, which are more likely to express traits related to overt virulence but--for the moment--also more likely to retain sensitivity to at least one effective antibiotic. The remaining infections are mostly caused by E. faecium, a species virtually devoid of known overt pathogenic traits but more likely to be resistant to even antibiotics of last resort. Effective control of multiple-drug resistant enterococci will require 1) better understanding of the interaction between enterococci, the hospital environment, and humans, 2) prudent antibiotic use, 3) better contact isolation in hospitals and other patient care environments, and 4) improved surveillance. Equally important is renewed vigor in the search for additional drugs, accompanied by the evolution of new therapeutic paradigms less vulnerable to the cycle of drug introduction and drug resistance. PMID:9621194

  12. Matched Interface and Boundary Method for Elasticity Interface Problems

    PubMed Central

    Wang, Bao; Xia, Kelin; Wei, Guo-Wei

    2015-01-01

    Elasticity theory is an important component of continuum mechanics and has had widely spread applications in science and engineering. Material interfaces are ubiquity in nature and man-made devices, and often give rise to discontinuous coefficients in the governing elasticity equations. In this work, the matched interface and boundary (MIB) method is developed to address elasticity interface problems. Linear elasticity theory for both isotropic homogeneous and inhomogeneous media is employed. In our approach, Lamé’s parameters can have jumps across the interface and are allowed to be position dependent in modeling isotropic inhomogeneous material. Both strong discontinuity, i.e., discontinuous solution, and weak discontinuity, namely, discontinuous derivatives of the solution, are considered in the present study. In the proposed method, fictitious values are utilized so that the standard central finite different schemes can be employed regardless of the interface. Interface jump conditions are enforced on the interface, which in turn, accurately determines fictitious values. We design new MIB schemes to account for complex interface geometries. In particular, the cross derivatives in the elasticity equations are difficult to handle for complex interface geometries. We propose secondary fictitious values and construct geometry based interpolation schemes to overcome this difficulty. Numerous analytical examples are used to validate the accuracy, convergence and robustness of the present MIB method for elasticity interface problems with both small and large curvatures, strong and weak discontinuities, and constant and variable coefficients. Numerical tests indicate second order accuracy in both L∞ and L2 norms. PMID:25914439

  13. Global Regularization Method for Planar Restricted Three-body Problem

    NASA Astrophysics Data System (ADS)

    Sharaf, M. A.; Dwidar, H. R.

    2015-12-01

    In this paper, global regularization method for planar restricted three-body problem is purposed by using the transformation z=x+iy=ν cos n(u+iv), where i=√{-1}, 0 < ν ≤ 1 and n is a positive integer. The method is developed analytically and computationally. For the analytical developments, analytical solutions in power series of the pseudo-time τ are obtained for positions and velocities (u,v,u',v') and (x,y,dot{x},dot{y}) in both regularized and physical planes respectively, the physical time {t} is also obtained as power series in τ. Moreover, relations between the coefficients of the power series are obtained for two consequent values of {n}. Also, we developed analytical solutions in power series form for the inverse problem of finding τ in terms of {t}. As typical examples, three symbolic expressions for the coefficients of the power series were developed in terms of the initial values. As to the computational developments, the global regularized equations of motion are developed together with their initial values in forms suitable for digital computations using any differential equations solver. On the other hand, for the numerical evolutions of power series, an efficient method depending on the continued fraction theory is provided.

  14. RepurposeVS: A Drug Repurposing-Focused Computational Method for Accurate Drug-Target Signature Predictions.

    PubMed

    Issa, Naiem T; Peters, Oakland J; Byers, Stephen W; Dakshanamurthy, Sivanesan

    2015-01-01

    We describe here RepurposeVS for the reliable prediction of drug-target signatures using X-ray protein crystal structures. RepurposeVS is a virtual screening method that incorporates docking, drug-centric and protein-centric 2D/3D fingerprints with a rigorous mathematical normalization procedure to account for the variability in units and provide high-resolution contextual information for drug-target binding. Validity was confirmed by the following: (1) providing the greatest enrichment of known drug binders for multiple protein targets in virtual screening experiments, (2) determining that similarly shaped protein target pockets are predicted to bind drugs of similar 3D shapes when RepurposeVS is applied to 2,335 human protein targets, and (3) determining true biological associations in vitro for mebendazole (MBZ) across many predicted kinase targets for potential cancer repurposing. Since RepurposeVS is a drug repurposing-focused method, benchmarking was conducted on a set of 3,671 FDA approved and experimental drugs rather than the Database of Useful Decoys (DUDE) so as to streamline downstream repurposing experiments. We further apply RepurposeVS to explore the overall potential drug repurposing space for currently approved drugs. RepurposeVS is not computationally intensive and increases performance accuracy, thus serving as an efficient and powerful in silico tool to predict drug-target associations in drug repurposing. PMID:26234515

  15. Simulating the postprandial stomach: biorelevant test methods for the estimation of intragastric drug dissolution.

    PubMed

    Koziolek, Mirko; Garbacz, Grzegorz; Neumann, Marco; Weitschies, Werner

    2013-06-01

    Intragastric drug release from solid oral dosage forms can be affected by altered physicochemical and mechanical conditions in the upper gastrointestinal (GI) tract. Food effects may lead to changes of one or more pharmacokinetic parameters and, hence, influence drug plasma levels. This can result in severe consequences such as adverse drug reactions or even therapy failure. This review highlights different examples of drug performance under fed conditions. Various reasons such as delayed gastric emptying and pH-dependent solubility of the API as well as intragastric location and movement profiles of solid dosage forms can account for changed drug dissolution. Over the past years, several biorelevant media (e.g., fed state simulated gastric fluid) have been developed with the aim to approach the physiological situation regarding parameters such as pH, buffer capacity, surface tension, and osmolality. It was shown in different in vitro experiments that all of these factors can have an impact on drug dissolution. Besides the application of complex media such as milk or nutritional drinks, the dynamic changes of the gastric content were depicted in recent studies. The capabilities, limitations, and applicability of newly established test setups for the biorelevant simulation of intragastric drug delivery behavior are discussed. Simple test devices (e.g., rotating beaker or dissolution stress test) are mainly used for the biopharmaceutical evaluation of certain problems such as the impact of pressure or shear forces. On the other hand, complex biorelevant test devices (e.g., TNO TIM-1, Dynamic Gastric Model) have recently been introduced aiming at the simulation of multiple parameters characteristic for the postprandial upper GI tract. The different test methods are reviewed with respect to the spectrum of the simulated physiological factors and the degree of complexity. PMID:23654347

  16. Comparison of optimal design methods in inverse problems

    NASA Astrophysics Data System (ADS)

    Banks, H. T.; Holm, K.; Kappel, F.

    2011-07-01

    Typical optimal design methods for inverse or parameter estimation problems are designed to choose optimal sampling distributions through minimization of a specific cost function related to the resulting error in parameter estimates. It is hoped that the inverse problem will produce parameter estimates with increased accuracy using data collected according to the optimal sampling distribution. Here we formulate the classical optimal design problem in the context of general optimization problems over distributions of sampling times. We present a new Prohorov metric-based theoretical framework that permits one to treat succinctly and rigorously any optimal design criteria based on the Fisher information matrix. A fundamental approximation theory is also included in this framework. A new optimal design, SE-optimal design (standard error optimal design), is then introduced in the context of this framework. We compare this new design criterion with the more traditional D-optimal and E-optimal designs. The optimal sampling distributions from each design are used to compute and compare standard errors; the standard errors for parameters are computed using asymptotic theory or bootstrapping and the optimal mesh. We use three examples to illustrate ideas: the Verhulst-Pearl logistic population model (Banks H T and Tran H T 2009 Mathematical and Experimental Modeling of Physical and Biological Processes (Boca Raton, FL: Chapman and Hall/CRC)), the standard harmonic oscillator model (Banks H T and Tran H T 2009) and a popular glucose regulation model (Bergman R N, Ider Y Z, Bowden C R and Cobelli C 1979 Am. J. Physiol. 236 E667-77 De Gaetano A and Arino O 2000 J. Math. Biol. 40 136-68 Toffolo G, Bergman R N, Finegood D T, Bowden C R and Cobelli C 1980 Diabetes 29 979-90).

  17. Some problems in applications of the linear variational method

    NASA Astrophysics Data System (ADS)

    Pupyshev, Vladimir I.; Montgomery, H. E.

    2015-09-01

    The linear variational method is a standard computational method in quantum mechanics and quantum chemistry. As taught in most classes, the general guidance is to include as many basis functions as practical in the variational wave function. However, if it is desired to study the patterns of energy change accompanying the change of system parameters such as the shape and strength of the potential energy, the problem becomes more complicated. We use one-dimensional systems with a particle in a rectangular or in a harmonic potential confined in an infinite rectangular box to illustrate situations where a variational calculation can give incorrect results. These situations result when the energy of the lowest eigenvalue is strongly dependent on the parameters that describe the shape and strength of the potential. The numerical examples described in this work are provided as cautionary notes for practitioners of numerical variational calculations.

  18. Management of Energy and Environment Conservation: Current Methodical Problems

    NASA Astrophysics Data System (ADS)

    Michna, J.; Ekmanis, J.; Zeltins, N.; Zebergs, V.; Siemianowicz, J.

    2011-01-01

    The paper presents a continuation in the series of works devoted to the acute problems of energy use management in different periods of economic transition in the CEE countries. Research carried out by the team of scientists has resulted in creation of modern management methods. In particular, unitary indices were worked out which connect the consumption of energy carriers and environment pollutions in a definite time period and the values of production (services) realised in this period. The cooperation of researchers from different countries has given rise to the ICEEP (International Center of Energy and Environment Policy), where under research are issues of the risk management in the conditions of informational uncertainty, non-knowledge, as well as dynamic and stochastic behaviour of systems (processes). The main emphasis in the methodical approaches is given to the complex (strategic) thinking, which would be necessary for establishment of global regulations in the scope of energy and environment conservation.

  19. Boundary element method approach to magnetostatic wave problems

    NASA Astrophysics Data System (ADS)

    Yashiro, K.; Ohkawa, S.; Miyazaki, M.

    1985-03-01

    In this paper, the technique for application of the boundary element method (BEM) to analysis of magnetostatic waves (MSWs) is established. To show the availability of the technique, two types of waveguides for the MSW are studied; one is a waveguide constituting a YIG slab shielded with metal plates and the other is a waveguide consisting of an unshielded YIG slab. With the former structure the results obtained by the present technique are compared with the analytical solutions, and with the latter the BEM is compared with Marcatili's approximate method since there is no analytical solution in this case. Those comparisons are performed successfully for both cases. The paper concludes that the BEM is useful and effective for analysis of a wide range of MSW problems.

  20. Ophthalmic Drug Dosage Forms: Characterisation and Research Methods

    PubMed Central

    Baranowski, Przemysław; Karolewicz, Bożena; Gajda, Maciej; Pluta, Janusz

    2014-01-01

    This paper describes hitherto developed drug forms for topical ocular administration, that is, eye drops, ointments, in situ gels, inserts, multicompartment drug delivery systems, and ophthalmic drug forms with bioadhesive properties. Heretofore, many studies have demonstrated that new and more complex ophthalmic drug forms exhibit advantage over traditional ones and are able to increase the bioavailability of the active substance by, among others, reducing the susceptibility of drug forms to defense mechanisms of the human eye, extending contact time of drug with the cornea, increasing the penetration through the complex anatomical structure of the eye, and providing controlled release of drugs into the eye tissues, which allows reducing the drug application frequency. The rest of the paper describes recommended in vitro and in vivo studies to be performed for various ophthalmic drugs forms in order to assess whether the form is acceptable from the perspective of desired properties and patient's compliance. PMID:24772038

  1. Validated spectrophotometric methods for determination of some oral hypoglycemic drugs.

    PubMed

    Farouk, M; Abdel-Satar, O; Abdel-Aziz, O; Shaaban, M

    2011-02-01

    Four accurate, precise, rapid, reproducible, and simple spectrophotometric methods were validated for determination of repaglinide (RPG), pioglitazone hydrochloride (PGL) and rosiglitazone maleate (RGL). The first two methods were based on the formation of a charge-transfer purple-colored complex of chloranilic acid with RPG and RGL with a molar absorptivity 1.23 × 103 and 8.67 × 102 l•mol-1•cm-1 and a Sandell's sensitivity of 0.367 and 0.412 μg•cm-2, respectively, and an ion-pair yellow-colored complex of bromophenol blue with RPG, PGL and RGL with molar absorptivity 8.86 × 103, 6.95 × 103, and 7.06 × 103 l•mol-1•cm-1, respectively, and a Sandell's sensitivity of 0.051 μg•cm-2 for all ion-pair complexes. The influence of different parameters on color formation was studied to determine optimum conditions for the visible spectrophotometric methods. The other spectrophotometric methods were adopted for demtermination of the studied drugs in the presence of their acid-, alkaline- and oxidative-degradates by computing derivative and pH-induced difference spectrophotometry, as stability-indicating techniques. All the proposed methods were validated according to the International Conference on Harmonization guidelines and successfully applied for determination of the studied drugs in pure form and in pharmaceutical preparations with good extraction recovery ranges between 98.7-101.4%, 98.2-101.3%, and 99.9-101.4% for RPG, PGL, and RGL, respectively. Results of relative standard deviations did not exceed 1.6%, indicating that the proposed methods having good repeatability and reproducibility. All the obtained results were statistically compared to the official method used for RPG analysis and the manufacturers methods used for PGL and RGL analysis, respectively, where no significant differences were found. PMID:22466095

  2. Methods for the coupled Stokes-Darcy problem

    NASA Astrophysics Data System (ADS)

    Feuillebois, F.; Khabthani, S.; Elasmi, L.; Sellier, A.

    2010-11-01

    The motion of particles in a viscous fluid close to a porous membrane is modelled for the case when particles are large compared with the size of pores of the membrane. The hydrodynamic interactions of one particle with the membrane are detailed here. The model involves Stokes equations for the fluid motion around the particle together with Darcy equations for the flow in the porous membrane and Stokes equations for the flow on the other side of the membrane. Boundary conditions at the fluid-membrane interface are the continuity of pressure and velocity in the normal direction and the Beavers and Joseph slip condition on the fluid side in the tangential directions. The no-slip condition applies on the particle. This problem is solved here by two different methods. The first one is an extended boundary integral method (EBIM). A Green function is derived for the flow close to a porous membrane. This function is non-symmetric, leading to difficulties hindering the application of the classical boundary integral method (BIM). Thus, an extended method is proposed, in which the unknown distribution of singularities on the particle surface is not the stress, like in the classical boundary integral method. Yet, the hydrodynamic force and torque on the particle are obtained by integrals of this distribution on the particle surface. The second method consists in searching the solution as an asymptotic expansion in term of a small parameter that is the ratio of the typical pore size to the particle size. The various boundary conditions are taken into account at successive orders: order (0) simply represents an impermeable wall without slip and order (1) an impermeable wall with a peculiar slip prescribed by order (0); at least the 3rd order is necessary to enforce all boundary conditions. The methods are applied numerically to a spherical particle and comparisons are made with earlier works in particular cases.

  3. Condensed history Monte Carlo methods for photon transport problems

    PubMed Central

    Bhan, Katherine; Spanier, Jerome

    2007-01-01

    We study methods for accelerating Monte Carlo simulations that retain most of the accuracy of conventional Monte Carlo algorithms. These methods – called Condensed History (CH) methods – have been very successfully used to model the transport of ionizing radiation in turbid systems. Our primary objective is to determine whether or not such methods might apply equally well to the transport of photons in biological tissue. In an attempt to unify the derivations, we invoke results obtained first by Lewis, Goudsmit and Saunderson and later improved by Larsen and Tolar. We outline how two of the most promising of the CH models – one based on satisfying certain similarity relations and the second making use of a scattering phase function that permits only discrete directional changes – can be developed using these approaches. The main idea is to exploit the connection between the space-angle moments of the radiance and the angular moments of the scattering phase function. We compare the results obtained when the two CH models studied are used to simulate an idealized tissue transport problem. The numerical results support our findings based on the theoretical derivations and suggest that CH models should play a useful role in modeling light-tissue interactions. PMID:18548128

  4. New problems arising from old drugs: second-generation effects of acetaminophen.

    PubMed

    Tiegs, Gisa; Karimi, Khalil; Brune, Kay; Arck, Petra

    2014-09-01

    Acetaminophen (APAP)/paracetamol is one of the most commonly used over-the-counter drugs taken worldwide for treatment of pain and fever. Although considered as safe when taken in recommended doses not higher than 4 g/day, APAP overdose is currently the most important cause of acute liver failure (ALF). ALF may require liver transplantation and can be fatal. The reasons for APAP-related ALF are mostly intentional (suicidal) or unintentional overdose. However, results from large scale epidemiological studies provide increasing evidence for second generation effects of APAP, even when taken in pharmacological doses. Most strikingly, APAP medication during pregnancy has been associated with health problems including neurodevelopmental and behavioral disorders such as attention deficit hyperactivity disorder and increase in the risk of wheezing and incidence of asthma among offspring. This article reviews the epidemiological findings and aims to shed light into the molecular and cellular mechanisms responsible for APAP-mediated prenatal risk for asthma. PMID:25075430

  5. A multilayer method of fundamental solutions for Stokes flow problems

    NASA Astrophysics Data System (ADS)

    Boselli, F.; Obrist, D.; Kleiser, L.

    2012-07-01

    The method of fundamental solutions (MFS) is a meshless method for the solution of boundary value problems and has recently been proposed as a simple and efficient method for the solution of Stokes flow problems. The MFS approximates the solution by an expansion of fundamental solutions whose singularities are located outside the flow domain. Typically, the source points (i.e. the singularities of the fundamental solutions) are confined to a smooth source layer embracing the flow domain. This monolayer implementation of the MFS (monolayer MFS) depends strongly on the location of the user-defined source points: On the one hand, increasing the distance of the source points from the boundary tends to increase the convergence rate. On the other hand, this may limit the achievable accuracy. This often results in an unfavorable compromise between the convergence rate and the achievable accuracy of the MFS. The idea behind the present work is that a multilayer implementation of the MFS (multilayer MFS) can improve the robustness of the MFS by efficiently resolving different scales of the solution by source layers at different distances from the boundary. We propose a block greedy-QR algorithm (BGQRa) which exploits this property in a multilevel fashion. The proposed multilayer MFS is much more robust than the monolayer MFS and can compute Stokes flows on general two- and three-dimensional domains. It converges rapidly and yields high levels of accuracy by combining the properties of distant and close source points. The block algorithm alleviates the overhead of multiple source layers and allows the multilayer MFS to outperform the monolayer MFS.

  6. Prevention des Toxicomanies Aupres des Filles avec des Problemes de Comportement: Effets a Court Terme (Prevention of Drug Addiction in Girls with Behavior Problems: Short-Term Effects).

    ERIC Educational Resources Information Center

    Vitaro, Frank; And Others

    1992-01-01

    This article, written in French, describes and evaluates the first phase of a program to prevent drug addiction among 110 fifth-grade girls with behavior problems in Montreal (Quebec, Canada). Evaluation of the instructional program showed positive results for student knowledge level, attitudes, and behaviors and supported program continuation…

  7. The Drug Education Gap

    ERIC Educational Resources Information Center

    Reynolds, John C., Jr.

    1976-01-01

    Examines the problems of alcoholism, smoking and drug addiction and their influence on students. Suggests that intermediate and secondary schools can assist in alcohol and tobacco (the two legal drugs) programs through improved educational methods. (Author/RK)

  8. Superconvergent discontinuous Galerkin methods for second-order elliptic problems

    NASA Astrophysics Data System (ADS)

    Cockburn, Bernardo; Guzman, Johnny; Wang, Haiying

    2009-03-01

    We identify discontinuous Galerkin methods for second-order elliptic problems in several space dimensions having superconvergence properties similar to those of the Raviart-Thomas and the Brezzi-Douglas-Marini mixed methods. These methods use polynomials of degree kge0 for both the potential as well as the flux. We show that the approximate flux converges in L^2 with the optimal order of k+1 , and that the approximate potential and its numerical trace superconverge, in L^2 -like norms, to suitably chosen projections of the potential, with order k+2 . We also apply element-by-element postprocessing of the approximate solution to obtain new approximations of the flux and the potential. The new approximate flux is proven to have normal components continuous across inter-element boundaries, to converge in L^2 with order k+1 , and to have a divergence converging in L^2 also with order k+1 . The new approximate potential is proven to converge with order k+2 in L^2 . Numerical experiments validating these theoretical results are presented.

  9. Variational formulation of a moment problem quantization method

    NASA Astrophysics Data System (ADS)

    Handy, Carlos R.; Maweu, John; Atterberry, Leticia Soto

    1996-03-01

    The eigenvalue moment method (EMM) has proven to be an effective technique for generating converging lower and upper bounds to the bosonic ground state energy of singular, strongly coupled, quantum systems. Application of EMM theory requires an appropriate linearization of the highly nonlinear Hankel-Hadamard (HH) moment determinant constraints for the (n+1)×(n+1) Hankel matrices Mn[u]≡M̂n0+∑i=1msM̂niu i), dependent on the missing moment variables {u(i)}≡u. We propose an alternate variational formulation utilizing the functions Det(Mn+1[u])/Det(Mn[u]), which we prove to be locally convex over the missing moment subset satisfying the HH positivity conditions Det(Mν[u])≳0, for ν≤n. Additional features of this variational formulation facilitate its application to important problems such as the octic, sextic, and quartic anharmonic oscillators.

  10. A numerical method for interface problems in elastodynamics

    NASA Technical Reports Server (NTRS)

    Mcghee, D. S.

    1984-01-01

    The numerical implementation of a formulation for a class of interface problems in elastodynamics is discussed. This formulation combines the use of the finite element and boundary integral methods to represent the interior and the exteriro regions, respectively. In particular, the response of a semicylindrical alluvial valley in a homogeneous halfspace to incident antiplane SH waves is considered to determine the accuracy and convergence of the numerical procedure. Numerical results are obtained from several combinations of the incidence angle, frequency of excitation, and relative stiffness between the inclusion and the surrounding halfspace. The results tend to confirm the theoretical estimates that the convergence is of the order H(2) for the piecewise linear elements used. It was also observed that the accuracy descreases as the frequency of excitation increases or as the relative stiffness of the inclusion decreases.

  11. Modified semi-classical methods for nonlinear quantum oscillations problems

    SciTech Connect

    Moncrief, Vincent; Marini, Antonella; Maitra, Rachel

    2012-10-15

    We develop a modified semi-classical approach to the approximate solution of Schroedinger's equation for certain nonlinear quantum oscillations problems. In our approach, at lowest order, the Hamilton-Jacobi equation of the conventional semi-classical formalism is replaced by an inverted-potential-vanishing-energy variant thereof. With suitable smoothness, convexity and coercivity properties imposed on its potential energy function, we prove, using methods drawn from the calculus of variations together with the (Banach space) implicit function theorem, the existence of a global, smooth 'fundamental solution' to this equation. Higher order quantum corrections thereto, for both ground and excited states, can then be computed through the integration of associated systems of linear transport equations, derived from Schroedinger's equation, and formal expansions for the corresponding energy eigenvalues obtained therefrom by imposing the natural demand for smoothness on the (successively computed) quantum corrections to the eigenfunctions. For the special case of linear oscillators our expansions naturally truncate, reproducing the well-known exact solutions for the energy eigenfunctions and eigenvalues. As an explicit application of our methods to computable nonlinear problems, we calculate a number of terms in the corresponding expansions for the one-dimensional anharmonic oscillators of quartic, sectic, octic, and dectic types and compare the results obtained with those of conventional Rayleigh/Schroedinger perturbation theory. To the orders considered (and, conjecturally, to all orders) our eigenvalue expansions agree with those of Rayleigh/Schroedinger theory whereas our wave functions more accurately capture the more-rapid-than-gaussian decay known to hold for the exact solutions to these problems. For the quartic oscillator in particular our results strongly suggest that both the ground state energy eigenvalue expansion and its associated wave function expansion

  12. Other Drug Use and Abuse on Campus: The Scope of the Problem. Infofacts/Resources

    ERIC Educational Resources Information Center

    Ross, Virginia; DeJong, William

    2009-01-01

    Of all drugs abused on college and university campuses, alcohol causes the greatest harm. Other drugs (the prevention field uses the term "other drugs" to distinguish them from alcohol, which also is a drug) also take a significant toll--diminishing the quality of campus life, undermining academic performance, compromising students' health and…

  13. Chromatography-based methods for determining molar extinction coefficients of cytotoxic payload drugs and drug antibody ratios of antibody drug conjugates.

    PubMed

    Wang, Chunlei; Chen, Sike; Caceres-Cortes, Janet; Huang, Richard Y-C; Tymiak, Adrienne A; Zhang, Yingru

    2016-07-15

    UV spectrophotometry is widely used to determine the molar extinction coefficients (MECs) of cytotoxic drugs as well as the drug antibody ratios (DARs) of antibody drug conjugates (ADCs). However, the unknown purity of a drug due to interfering impurities can lead to erroneous MECs and DARs. Hence, reliable methods to accurately determine purity and the MECs of drugs with limited quantity is urgently needed in Drug Discovery. Such a method has been developed. It achieves absolute purity and accurate MEC determination by a single automated HPLC analysis that uses less than 5μg of material. Specifically, analytical HPLC separation with online UV detection was used to resolve impurities and measure absorbance from only the compound of interest. Simultaneously, an online chemiluminescence nitrogen detector (CLND) was used to determine the concentration of the analyte. The MECs were then calculated from the absorbance and concentration results. The accuracy of the method was demonstrated using caffeine and a commercial cytotoxic drug, DM1. This approach is particularly suited to analyzing mixtures or samples with low purities. Excellent reproducibility was demonstrated by analyzing a proprietary drug with linker synthesized from different batches with very different levels of purity. In addition, the MECs of drug with linker, along with ADC peak areas measured from size exclusion chromatography (SEC), were used to calculate DARs for 21 in-house ADCs. The DAR results were consistent with those obtained by MS analysis. PMID:27286648

  14. An enzymatic deconjugation method for the analysis of small molecule active drugs on antibody-drug conjugates.

    PubMed

    Li, Yi; Gu, Christine; Gruenhagen, Jason; Yehl, Peter; Chetwyn, Nik P; Medley, Colin D

    2016-01-01

    Antibody-drug conjugates (ADCs) are complex therapeutic agents that use the specific targeting properties of antibodies and the highly potent cytotoxicity of small molecule drugs to selectively eliminate tumor cells while limiting the toxicity to normal healthy tissues. Two critical quality attributes of ADCs are the purity and stability of the active small molecule drug linked to the ADC, but these are difficult to assess once the drug is conjugated to the antibody. In this study, we report a enzyme deconjugation approach to cleave small molecule drugs from ADCs, which allows the drugs to be subsequently characterized by reversed-phase high performance liquid chromatography. The model ADC we used in this study utilizes a valine-citrulline linker that is designed to be sensitive to endoproteases after internalization by tumor cells. We screened several proteases to determine the most effective enzyme. Among the 3 cysteine proteases evaluated, papain had the best efficiency in cleaving the small molecule drug from the model ADC. The deconjugation conditions were further optimized to achieve complete cleavage of the small molecule drug. This papain deconjugation approach demonstrated excellent specificity and precision. The purity and stability of the active drug on an ADC drug product was evaluated and the major degradation products of the active drug were identified. The papain deconjugation method was also applied to several other ADCs, with the results suggesting it could be applied generally to ADCs containing a valine-citrulline linker. Our results indicate that the papain deconjugation method is a powerful tool for characterizing the active small molecule drug conjugated to an ADC, and may be useful in ensuring the product quality, efficacy and the safety of ADCs. PMID:26891281

  15. A Method for Overcoming the Problem of Concept-Scale Interaction in Semantic Differential Research

    ERIC Educational Resources Information Center

    Bynner, John; Romney, David

    1972-01-01

    Data collected in a study of hospital staff attitudes to drug addicts and other types of patients are used to illustrate the problem of concept-scale interaction in semantic differential research. (Authors)

  16. Experimental analysis of nonlinear problems by optical methods

    NASA Astrophysics Data System (ADS)

    Laermann, Karl-Hans

    1994-11-01

    As an example of a geometrical nonlinear problem a thin plate-in-bending under large deflection is considered. To determine the inplane- as well as the bending stress-state the photoelastic reflection method and Ligtenberg's moire method are used; the measured information is evaluated according to the principles of integrated photoelasticity. As yet in photoelasticity it has always been supposed Hooke's law of elasticity is valid and consequently linear relations between birefringent effects and stresses are existing. However, in areas of high stress concentration and with reference to some of the mainly used photoelastic material nonlinear strain-stress relations must be introduced. A proper constitutive equation yields an advanced principal photoelastic equation, the solution of which is performed in an iterative procedure. It should be mentioned that extended material testing is demanded to get the various material parameters. Finally proper algorithms and the respective numerical evaluation procedures are described, to analyze plane stress-states, if the material shows viscoelastic response. Then the mechanical as well as the optical rheological response of material must be considered.

  17. Dimensional Analysis and Qualitative Methods in Problem Solving

    ERIC Educational Resources Information Center

    Pescetti, D.

    2008-01-01

    The primary application of dimensional analysis (DA) is in problem solving. Typically, the problem description indicates that a physical quantity Y(the unknown) is a function f of other physical quantities A[subscript 1], ..., A[subscript n] (the data). We propose a qualitative problem-solving procedure which consists of a parallel decomposition…

  18. Using Problem Fields as a Method of Change.

    ERIC Educational Resources Information Center

    Pehkonen, Erkki

    1992-01-01

    Discusses the rationale and use of problem fields which are sets of related and/or connected open-ended problem-solving tasks within mathematics instruction. Polygons with matchsticks and the number triangle are two examples of problem fields presented along with variations in conditions that promote other matchstick puzzles. (11 references) (JJK)

  19. PREDICT: a method for inferring novel drug indications with application to personalized medicine

    PubMed Central

    Gottlieb, Assaf; Stein, Gideon Y; Ruppin, Eytan; Sharan, Roded

    2011-01-01

    Inferring potential drug indications, for either novel or approved drugs, is a key step in drug development. Previous computational methods in this domain have focused on either drug repositioning or matching drug and disease gene expression profiles. Here, we present a novel method for the large-scale prediction of drug indications (PREDICT) that can handle both approved drugs and novel molecules. Our method is based on the observation that similar drugs are indicated for similar diseases, and utilizes multiple drug–drug and disease–disease similarity measures for the prediction task. On cross-validation, it obtains high specificity and sensitivity (AUC=0.9) in predicting drug indications, surpassing existing methods. We validate our predictions by their overlap with drug indications that are currently under clinical trials, and by their agreement with tissue-specific expression information on the drug targets. We further show that disease-specific genetic signatures can be used to accurately predict drug indications for new diseases (AUC=0.92). This lays the computational foundation for future personalized drug treatments, where gene expression signatures from individual patients would replace the disease-specific signatures. PMID:21654673

  20. Methodical problems of magnetic field measurements in umbra of sunspots

    NASA Astrophysics Data System (ADS)

    Lozitska, N. I.; Lozitsky, V. G.; Andryeyeva, O. A.; Akhtemov, Z. S.; Malashchuk, V. M.; Perebeynos, V. A.; Stepanyan, N. N.; Shtertser, N. I.

    2015-02-01

    Visual measurements of magnetic field strengths in sunspot umbra provide data on magnetic field strength modulus directly, i.e., irrespective from any solar atmosphere model assumptions. In order to increase the accuracy of calculation of the solar magnetic indexes, such as B ‾ max or Bsp, the inclusion of all available data from different observatories is needed. In such measurements some methodical problems arise, which bring about inconsistency of the data samples combined from different sources; this work describes the problems at hand and proposes solutions on how to eliminate the inconsistencies. Data sets of sunspot magnetic field strength visual measurements from Mt. Wilson, Crimea and Kyiv observatories in 2010-2012 have been processed. It is found that two measurement modes of Zeeman split, σ → σ and σ → π, yield almost the same results, if data rows are long enough (over ∼100 sunspots in central area of Sun, r < 0.7 R). It is generally held that the most reliable measurement results are obtained for magnetic fields that exceed 2400 G. However, the empirical comparison of the internal data consistency of the samples produced by different observers shows that for reliable results this limit can be lowered down to 1100 G. To increase the precision of measurements, empirical calibration of the line-shifter is required by using closely positioned telluric lines. Such calibrations have been performed at Kyiv and Crimea, but as far as we know, it has not been carried out at Mt. Wilson observatory after its diffraction grate was replaced in 1994. Taking into consideration the highest quality and coverage of Mt. Wilson sunspot observational data, the authors are convinced that reliable calibration of its instrument by narrow telluric lines is definitely required.

  1. Estimating the prevalence of drug misuse in Dundee, Scotland: an application of capture-recapture methods.

    PubMed Central

    Hay, G; McKeganey, N

    1996-01-01

    STUDY OBJECTIVES: To apply capture-recapture methods to provide an estimate of the prevalence of opiate and benzodiazepine misuse in Dundee, Scotland. DESIGN: A four sample capture-recapture method using data from both statutory and non-statutory data sources to estimate drug misuse prevalence in Dundee between January 1990 and December 1994. PARTICIPANTS: Users of benzodiazepines or opiates residing within Dundee. RESULTS: Altogether 855 drug misusers were identified from various sources within Dundee; many were identified from more than one source. Using this data, the estimated unknown population was 1702, giving a total population of 2557 (95% confidence interval (CI) 1974, 3458) who misuse benzodiazepines or opiates. This represents a prevalence of 28.8 (95% CI 22.3, 39.0) per thousand. CONCLUSIONS: Capture-recapture techniques can be applied to statutory and non-statutory agency data to produce an estimate of at least certain sections of the drug misusing population. However, it is important to recognise the limitations of this methodology and in future to seek to combine a range of approaches to the problem of estimating prevalence rather than sticking rigidly to any single approach. PMID:8882234

  2. Problems of Drug Dependence, 2002: Proceedings of the 64th Annual Scientific Meeting, The College on Problems of Drug Dependence, Inc.

    ERIC Educational Resources Information Center

    Dewey, William L., Ed.; Harris, Louis S., Ed.

    This publication summarizes the activities of the most recent meeting of the nation's most influential drug abuse professionals and measures progress in a variety of areas. Outcomes of symposia, meetings, and presentations are discussed. Symposia include: (1) "Is Dopamine the Answer? Evidence for the Importance of Other Systems in the…

  3. [Animal models of drug dependence using the drug self-administration method].

    PubMed

    Yamamoto, T; Yabuuchi, K; Yamaguchi, T; Nakamichi, M

    2001-01-01

    This paper will review 1) experimental models of drug-seeking behavior and 2) mechanisms underlying the behavior, focusing on cocaine self-administration. After the acquisition of self-administration, vigorous lever-pressing is generally observable after the drug was replaced by saline. This lever-pressing behavior under saline infusion can be considered "drug-seeking behavior". Drug-seeking behavior is reinstated by non-contingent injection of the drug, stress exposure and presentation of drug-associated stimuli even after extinction. This is called a relapse/reinstatement model. Electrophysiological studies showed that the majority of accumbal neurons is tonically inhibited during cocaine self-administration and exhibited phasic increases in firing time-locked to cocaine self-infusion, which might represent the craving state or drive animals to drug-seeking behavior. Voltammetry and microdialysis studies indicated that the timing of drug-seeking responses can be predicted from fluctuations in accumbal extracellular dopamine concentration. Whereas dopamine D2-like agonists reinstated extinguished cocaine-seeking behavior, D1-like agonists prevented the relapse in cocaine-seeking behavior induced by cocaine itself. Given that an AMPA receptor antagonist, but not dopamine antagonist, prevented cocaine-seeking behavior induced by cocaine, glutamate transmission in the nucleus accumbens is thought to be important for expression of craving or drug-seeking behavior. PMID:11233296

  4. Drug use and mental health problems among prison inmates--results from a nation-wide prison population study.

    PubMed

    Friestad, Christine; Kjelsberg, Ellen

    2009-01-01

    Prisons all over the western world are known to be inhabited by a biased sample of the population. More information is needed on how problems in diverse areas interact. The present study investigated how general welfare deficiencies, drug use and mental health problems were related in a representative prison population. Data stem from a level-of-living survey among a nationwide representative sample of Norwegian prison inmates. The sample was drawn randomly from the official register of prison inmates. Data were collected through structured personal interviews (computer assisted). Analyses presented in this paper are based on the male part of the sample (n=225). Only 24% of male prisoners were affected by neither drug use problems nor mental health problems. Investigating the relationship between variables indicated an increasing accumulation of childhood stressors and general welfare deficiencies with increasing drug use and mental health problems. As health problems are intertwined with more general social problems, health promotion among prison inmates is clearly a multidisciplinary task, requiring close collaboration between different service providers and systems of care. PMID:19034714

  5. Boundary-integral methods in elasticity and plasticity. [solutions of boundary value problems

    NASA Technical Reports Server (NTRS)

    Mendelson, A.

    1973-01-01

    Recently developed methods that use boundary-integral equations applied to elastic and elastoplastic boundary value problems are reviewed. Direct, indirect, and semidirect methods using potential functions, stress functions, and displacement functions are described. Examples of the use of these methods for torsion problems, plane problems, and three-dimensional problems are given. It is concluded that the boundary-integral methods represent a powerful tool for the solution of elastic and elastoplastic problems.

  6. Methods of providing prescription drug benefits in health plans.

    PubMed

    Curtiss, F R

    1986-10-01

    Drug-benefit programs in health plans that offer varying degrees of risk to pharmacy providers are described. Administrators of health plans attempt to control the total cost of a drug benefit by controlling the cost per prescription, number of prescriptions, and administrative expenses. Specific ways to control these factors, such as through discounted product costs, patient copayments, and audits of prescribing practices, are described. Drug-benefit programs generally follow one of three models: fee-for-service contracts, hybrid fee-for-service risk contracts, and full-risk contracts. Examples of plans within each model are described. Full-risk contracts that provide drug benefits on a capitation basis put pharmacy providers at most risk of financial loss since physicians control prescribing. Pharmacists can control their risk by establishing a joint pharmacist and physician prescription fund that includes contract provisions limiting maximum losses, defining exceptions to the drug benefit, and paying close attention to payment schedules and characteristics of the program administrator. Antitrust issues associated with these new types of drug-benefit plans are described. Drug-benefit programs involving risk contracts can aid pharmacy practice by improving cash flow via negotiated prepayments, defining an enrolled patient population, and creating opportunities for generating additional revenue. Drug-benefit programs involving full-risk contracts and hybrid fee-for-service risk contracts will continue to develop, and understanding these models is the first step toward successful risk contracting by pharmacists. PMID:3788994

  7. Don’t Flush! Why Your Drug Disposal Method Matters

    EPA Science Inventory

    April 30th is the U.S. Drug Enforcement Administration’s National Drug Take-Back Day. All over the country there will be facilities accepting any unwanted or expired medications from 10:00 AM – 2:00 PM – it is the perfect opportunity to clean out your medicine cabinet while simu...

  8. An efficient iterative method for the generalized Stokes problem

    SciTech Connect

    Sameh, A.; Sarin, V.

    1996-12-31

    This paper presents an efficient iterative scheme for the generalized Stokes problem, which arises frequently in the simulation of time-dependent Navier-Stokes equations for incompressible fluid flow. The general form of the linear system is where A = {alpha}M + vT is an n x n symmetric positive definite matrix, in which M is the mass matrix, T is the discrete Laplace operator, {alpha} and {nu} are positive constants proportional to the inverses of the time-step {Delta}t and the Reynolds number Re respectively, and B is the discrete gradient operator of size n x k (k < n). Even though the matrix A is symmetric and positive definite, the system is indefinite due to the incompressibility constraint (B{sup T}u = 0). This causes difficulties both for iterative methods and commonly used preconditioners. Moreover, depending on the ratio {alpha}/{nu}, A behaves like the mass matrix M at one extreme and the Laplace operator T at the other, thus complicating the issue of preconditioning.

  9. Thick-Restart Laczos Method for Symmetric Eigenvalue Problems

    Energy Science and Technology Software Center (ESTSC)

    1999-01-01

    This software package implements the thick-restart Lanczos method. It can be used on either a single address space machine or distributed parallel machine. The user can choose to implement or use a matrix-vector multiplication routine in any form convenient. Most of the arithmetic computations in the software are done through calls to BLAS and LAPACK. The software is written in Fortran 90. Because Fortran 90 offers many utility functions such functions such as dynamic memorymore » management, timing functions, random number generator and so on, the program is easily portable to different machines without modifying the source code. It can also be easily accessed from other language such as C or C-+. Since the software is highly modularized, it is relatively easy to adopt it for different type of situations. For example if the eigenvalue problem may have some symmetry and only a portion of the physical domain is discretized, then the dot-product routine needs to be modified. In this software, this modification is limited to one subroutine. It also can be instructed to write checkpoint files so that it can be restarted at a later time.« less

  10. Violent Behaviors in Drug Addiction: Differential Profiles of Drug-Addicted Patients with and without Violence Problems

    ERIC Educational Resources Information Center

    Fernandez-Montalvo, Javier; Lopez-Goni, Jose J.; Arteaga, Alfonso

    2012-01-01

    This study explored the prevalence of violent behaviors in patients who are addicted to drugs. A sample of 252 addicted patients (203 male and 49 female) who sought outpatient treatment was assessed. Information on violent behaviors, sociodemographic factors, consumption factors (assessed by the European version of the Addiction Severity Index…

  11. 21 CFR 530.24 - Procedure for announcing analytical methods for drug residue quantification.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Procedure for announcing analytical methods for...-Producing Animals § 530.24 Procedure for announcing analytical methods for drug residue quantification. (a) FDA may issue an order announcing a specific analytical method or methods for the quantification...

  12. Non-conforming finite element methods for transmission eigenvalue problem

    NASA Astrophysics Data System (ADS)

    Yang, Yidu; Han, Jiayu; Bi, Hai

    2016-08-01

    The transmission eigenvalue problem is an important and challenging topic arising in the inverse scattering theory. In this paper, for the Helmholtz transmission eigenvalue problem, we give a weak formulation which is a nonselfadjoint linear eigenvalue problem. Based on the weak formulation, we first discuss the non-conforming finite element approximation, and prove the error estimates of the discrete eigenvalues obtained by the Adini element, Morley-Zienkiewicz element, modified-Zienkiewicz element et. al. And we report some numerical examples to validate the efficiency of our approach for solving transmission eigenvalue problem.

  13. Managing Mental Health Problems in Everyday Life: Drug Treatment Client's Self-Care Strategies

    ERIC Educational Resources Information Center

    Holt, Martin; Treloar, Carla

    2008-01-01

    Little is understood about the self-care activities undertaken by drug treatment clients. Using data from a qualitative study of drug treatment and mental health we identify the self-care practices of drug treatment clients diagnosed with anxiety and depression. Seventy-seven participants were interviewed in four sites across Australia.…

  14. The drug abuse problem in Peninsular Malaysia: parent and child differences in knowledge, attitudes and perceptions.

    PubMed

    Low, W Y; Zulkifli, S N; Yusof, K; Batumalail, S; Aye, K W

    1996-10-01

    A survey was carried out to gather information on knowledge, attitudes and perception of parents and their children in relation to drug abuse matters. Significantly more teenagers knew more of the cause of drug addiction, as well as places for treatment and rehabilitation. Both teenagers and parents were also aware of reasons why drug addicts find it difficult to change their habits, mainly lacking motivation to stop taking drugs and that drug addicts do not have the power to control themselves. Teenagers were significantly more aware of effects of negative parental attitudes contributing to drug abuse, apart from school factors. Personal experiences before abusing drugs such as knowledge of pleasurable effects of drugs and where to obtain them has also a role to play in leading to drug abuse. There was also agreement that unfulfilled needs such as 'not being respected recognised for ones capabilities' and 'not being loved or treated fairly by parents', were causes of drug abuse. Significantly more teenagers knew of the ways of abusing drugs, mainly by injection, smoking and sniffing, and also sources of information via the mass media, social clubs, rehabilitation centres and schools. However, both the parents and teenagers were relatively ignorant of the long term effects of abusing drugs. PMID:8889409

  15. Development of numerical methods to problems of micromechanics

    NASA Astrophysics Data System (ADS)

    Garcia-Martinez, Jose Ramon

    In this dissertation we utilize the finite element method to investigate three micromechanical problems. In Chapter 2, we study the compliance contribution tensor H of multiple branched cracks. The cracks grow from a deltoid pore at their center into a triple crack. For plain strain conditions, two-dimensional models of the branched crack are modeled and solved in ABAQUS. The displacement field over the surface of the branched crack and the deltoid is curve fitted to carry out the integral surface of the compliance contribution tensor H. The predicted values are in good agreement with analytical solution. In Chapter 3 a three-dimensional finite element program using an unaligned mesh with an eight-node isoparametric element is developed to study the compliance contribution tensor H of cavities with superellipsoid shapes. A mesh clustering algorithm to increase the number of elements inside and near the superellipsoid surface to obtain a mesh independent solution is used. The numerical results are compared with the analytical solution of a sphere; the error of the numerical approximation varied from 8 to 11%. It is found that the number of elements inside the superellipsoid are insufficient. An algorithm to mesh independently the volumes inside and outside the cube is proposed to increase the accuracy in the calculation of H. As n1 and n2 increase, the numerical solutions show that, H1111 → 0 and H2211 → 0. Although, for these concave shapes no analytical solution exists a bound of 0 for the terms H 1111 and H2211 is suggested. Finally, in Chapter 4 a numerical verification of the cross-property connection between the effective fluid permeability and the effective electrical conductivity is study. A molecular dynamics algorithm is used to generate a set of different microstructural patterns. The volumetric average over a cubic volume is used to obtain the effective electrical conductivity and the effective fluid permeability. The tortuosity of the porous phase

  16. Web-Based Cognitive Behavioral Relapse Prevention Program With Tailored Feedback for People With Methamphetamine and Other Drug Use Problems: Development and Usability Study

    PubMed Central

    Miyamoto, Yuki; Kawakami, Norito; Matsumoto, Toshihiko

    2016-01-01

    Background Although drug abuse has been a serious public health concern, there have been problems with implementation of treatment for drug users in Japan because of poor accessibility to treatment, concerns about stigma and confidentiality, and costs. Therapeutic interventions using the Internet and computer technologies could improve this situation and provide more feasible and acceptable approaches. Objective The objective of the study was to show how we developed a pilot version of a new Web-based cognitive behavioral relapse prevention program with tailored feedback to assist people with drug problems and assessed its acceptance and usability. Methods We developed the pilot program based on existing face-to-face relapse prevention approaches using an open source Web application to build an e-learning website, including relapse prevention sessions with videos, exercises, a diary function, and self-monitoring. When users submitted exercise answers and their diary, researchers provided them with personalized feedback comments using motivational interviewing skills. People diagnosed with drug dependence were recruited in this pilot study from a psychiatric outpatient ward and nonprofit rehabilitation facilities and usability was evaluated using Internet questionnaires. Overall, website usability was assessed by the Web Usability Scale. The adequacy of procedures in the program, ease of use, helpfulness of content, and adverse effects, for example, drug craving, mental distress, were assessed by original structured questionnaires and descriptive form questions. Results In total, 10 people participated in the study and completed the baseline assessment, 60% completed all relapse prevention sessions within the expected period. The time needed to complete one session was about 60 minutes and most of the participants took 2 days to complete the session. Overall website usability was good, with reasonable scores on subscales of the Web Usability Scale. The participants

  17. Methods and Strategies: Modeling Problem-Based Instruction

    ERIC Educational Resources Information Center

    Sterling, Donna R.

    2007-01-01

    Students get excited about science when they investigate real scientific problems in the classroom, especially when the investigation extends over several weeks. This article describes a health-science problem-based learning (PBL) investigation that a group of teachers and teacher educators devised together for a group of fourth- to sixth-grade…

  18. The Method To Acquire the Strategic Knowledge on Problem Solving.

    ERIC Educational Resources Information Center

    Takaoka, Ryo; Okamoto, Toshio

    As a person learns, his problem solving ability improves and one reason for this is the increased acquisition of "macro-rules" which make problem solving more efficient. An intelligent computer assisted learning (ICAI) system is being developed which automatically acquires the useful knowledge from the domain experts; as experts give the learning…

  19. The Mimetic Finite Element Method and the Virtual Element Method for elliptic problems with arbitrary regularity.

    SciTech Connect

    Manzini, Gianmarco

    2012-07-13

    We develop and analyze a new family of virtual element methods on unstructured polygonal meshes for the diffusion problem in primal form, that use arbitrarily regular discrete spaces V{sub h} {contained_in} C{sup {alpha}} {element_of} N. The degrees of freedom are (a) solution and derivative values of various degree at suitable nodes and (b) solution moments inside polygons. The convergence of the method is proven theoretically and an optimal error estimate is derived. The connection with the Mimetic Finite Difference method is also discussed. Numerical experiments confirm the convergence rate that is expected from the theory.

  20. An improved method for the characterization of supersaturation and precipitation of poorly soluble drugs using pulsatile microdialysis (PMD).

    PubMed

    Shah, Kosha B; Patel, Piyush G; Khairuzzaman, Akm; Bellantone, Robert A

    2014-07-01

    In current pharmaceutical drug discovery, most candidates are poorly soluble in water, which can result in poor bioavailability. To overcome this problem, formulations that create supersaturation of the drug are a well-studied alternative. Characterizing the dissolution from these systems is challenging because conventional methods, such as sampling with a syringe then filtering with a 0.2-0.45 μm filter before an HPLC assay, can overestimate the concentration of dissolved drug by allowing nuclei or small precipitated particles to pass, which then dissolve in the HPLC mobile phase. Nuclei and small particles can also cause overestimation of the dissolved concentration when using optical methods. Such overestimations can lead to failure of in vivo prediction of drug bioavailability from supersaturated systems. This paper reports a novel method to determine the free dissolved drug concentration in a dissolution medium using pulsatile microdialysis (PMD). Ibuprofen was used as a model drug for determining precipitation and supersaturation. Supersaturation was induced chemically by changing pH, and also by dissolution/release from an in-house formulation. The adaptation of a previously developed PMD model is summarized, and experimental results comparing dissolved concentrations determined using PMD and direct sampling by syringe and filtering are presented. PMID:24709210

  1. Methods for comparing drug policies--the utility of composite drug harm indexes.

    PubMed

    Ritter, Alison

    2009-11-01

    One of the challenges for drug policy research is being able to compare policy options and outcomes. The development of indexes, such as the UK Drug Harm Index or the UNODC Illicit Drug Index is a way to systematically enable such comparisons. An Index is a single common metric that represents the diverse outcomes or consequences of drug use. An Index may be used for performance monitoring within one country/region over time; to establish societal benefit of drug policies as expressed in social costs saved; to compare countries or regions; or for comparative policy analysis. Clarity of purpose is important in how an Index is used. The consequences or outcomes that can be combined into a single Index include health consequences, crime consequences, public amenity, pain and suffering, labour market outcomes, and drug manufacture and trafficking activity. The choice of outcomes for inclusion is driven by the purpose but also often by practical considerations, such as data availability. The weighting of the consequences is an important consideration in translating the outcomes into a common metric. A monetary unit has a number of advantages: it is a unit that can be measured across diverse impacts; it gives implicit "weighting" of harms; and it is intuitive for policy makers and community. On the other hand, it represents an economic perspective. No one Index will be regarded as suitable and appropriate by every stakeholder and ongoing research effort on Indexes is an important foundational research activity to advance illicit drug policy. PMID:19356915

  2. Artificial Neural Network Methods Applied to Drug Discovery for Neglected Diseases.

    PubMed

    Scotti, Luciana; Ishiki, Hamilton; Mendonça Júnior, Francisco J B; da Silva, Marcelo S; Scotti, Marcus T

    2015-01-01

    Among the chemometric tools used in rational drug design, we find artificial neural network methods (ANNs), a statistical learning algorithm similar to the human brain, to be quite powerful. Some ANN applications use biological and molecular data of the training series that are inserted to ensure the machine learning, and to generate robust and predictive models. In drug discovery, researchers use this methodology, looking to find new chemotherapeutic agents for various diseases. The neglected diseases are a group of tropical parasitic diseases that primarily affect poor countries in Africa, Asia, and South America. Current drugs against these diseases cause side effects, are ineffective during the chronic stages of the disease, and are often not available to the needy population, have relative high toxicity, and face developing resistance. Faced with so many problems, new chemotherapeutic agents to treat these infections are much needed. The present review reports on neural network research, which studies new ligands against Chagas' disease, sleeping sickness, malaria, tuberculosis, and leishmaniasis; a few of the neglected diseases. PMID:26234510

  3. Community "San Gregorio." A Christian Educative Response to the Problem of Drug Abuse in Youth Aged 12-18 Years.

    ERIC Educational Resources Information Center

    Lamus, Jose Antonio Lopez; Sarmiento, Albeiro Saldana

    This pamphlet describes the "San Gregorio" pilot program in Latin America, the first of its type on the continent as a program specifically for adolescent drug addicts. The Christian educative program is designed for males 12-18 years of age, who are addicted to psycho-active substances and evidence serious behavioral problems. It is also aimed at…

  4. Research, Action, and the Community: Experiences in the Prevention of Alcohol and Other Drug Problems. OSAP Prevention Monograph-4.

    ERIC Educational Resources Information Center

    Giesbrecht, Norman, Ed.; And Others

    This document presents modified and updated papers from a symposium held to examine alcohol and drug abuse prevention efforts worldwide. It contains 32 papers from 11 countries; papers include: (1) "Community Action on Alcohol Problems: The Demonstration Project as an Unstable Mixture" (Robin Room); (2) "Perspectives on the Community in Action…

  5. Multi-level adaptive finite element methods. 1: Variation problems

    NASA Technical Reports Server (NTRS)

    Brandt, A.

    1979-01-01

    A general numerical strategy for solving partial differential equations and other functional problems by cycling between coarser and finer levels of discretization is described. Optimal discretization schemes are provided together with very fast general solvers. It is described in terms of finite element discretizations of general nonlinear minimization problems. The basic processes (relaxation sweeps, fine-grid-to-coarse-grid transfers of residuals, coarse-to-fine interpolations of corrections) are directly and naturally determined by the objective functional and the sequence of approximation spaces. The natural processes, however, are not always optimal. Concrete examples are given and some new techniques are reviewed. Including the local truncation extrapolation and a multilevel procedure for inexpensively solving chains of many boundary value problems, such as those arising in the solution of time-dependent problems.

  6. Survey of current component reliability problems and methods for prevention.

    NASA Technical Reports Server (NTRS)

    Hamiter, L.; Villella, F.

    1972-01-01

    The current reliability problems related to electronic components and microcircuits are presented in this paper. Specific process controls, design, materials, application constraints, destructive testing, electrical tests, and procedures for implementation are recommended to improve the reliability of selected electronic components.

  7. Law enforcement approaches and measures used in countering illicit drug problems in Thailand.

    PubMed

    Yodmani, C

    1992-01-01

    The Government of Thailand, which has long recognized the serious threat posed by illicit drugs, has implemented stringent law enforcement measures aimed at suppressing illicit drug trafficking by dismantling clandestine laboratories, intercepting essential chemicals, effecting significant seizures and eradicating illicit crops. In addition, the Government has taken steps to initiate the enactment of legislation providing for the confiscation of proceeds derived from illicit drug trafficking activity. Furthermore, it has maintained and strengthened its already close bilateral and multilateral cooperation in the field of drug abuse control. PMID:1477702

  8. Solving Fuzzy Optimization Problem Using Hybrid Ls-Sa Method

    NASA Astrophysics Data System (ADS)

    Vasant, Pandian

    2011-06-01

    Fuzzy optimization problem has been one of the most and prominent topics inside the broad area of computational intelligent. It's especially relevant in the filed of fuzzy non-linear programming. It's application as well as practical realization can been seen in all the real world problems. In this paper a large scale non-linear fuzzy programming problem has been solved by hybrid optimization techniques of Line Search (LS), Simulated Annealing (SA) and Pattern Search (PS). As industrial production planning problem with cubic objective function, 8 decision variables and 29 constraints has been solved successfully using LS-SA-PS hybrid optimization techniques. The computational results for the objective function respect to vagueness factor and level of satisfaction has been provided in the form of 2D and 3D plots. The outcome is very promising and strongly suggests that the hybrid LS-SA-PS algorithm is very efficient and productive in solving the large scale non-linear fuzzy programming problem.

  9. Commentary on “Alzheimer’s disease drug development and the problem of the blood-brain barrier”

    PubMed Central

    Simpkins, James W.

    2016-01-01

    The perspective by Dr. William Pardridge entitled “Alzheimer’s Disease Drug Discovery and the Problem of the Blood-Brain Barrier” makes a strong case for the imbalance in resource distribution to the drug-discovery and brain drug delivery processes, where the latter received less than 1% of the investment of the former. My own calculations are consistent with this striking imbalance. Dr. Pardridge predicts that current trials of passive immunity against β-amyloid peptide will likely fail, whereas past trials of active immunization exhibited trial-ending side effects, in part because of disruption of the integrity of the blood-brain barrier. To bring an assessment of the physiology of the blood-brain barrier and the brain delivery of drugs to the fore, several changes are needed in the way we perceive the problem, train our young scientists, organize research efforts, and incentivize reaching our common goals of effective drug therapy for Alzheimer’s disease. PMID:19751923

  10. Iterative method for elliptic problems on regions partitioned into substructures

    SciTech Connect

    Bramble, J.H.; Pasciak, J.E.; Schatz, A.H.

    1986-04-01

    Some new preconditioners for discretizations of elliptic boundary problems are studied. With these preconditioners, the domain under consideration is broken into subdomains and preconditioners are defined which only require the solution of matrix problems on the subdomains. Analytic estimates are given which guarantee that under appropriate hypotheses, the preconditioned iterative procedure converges to the solution of the discrete equations with a rate per iteration that is independent of the number of unknowns. Numerical examples are presented which illustrate the theoretically predicted iterative convergence rates.

  11. Extended particle difference method for weak and strong discontinuity problems: part II. Formulations and applications for various interfacial singularity problems

    NASA Astrophysics Data System (ADS)

    Yoon, Young-Cheol; Song, Jeong-Hoon

    2014-06-01

    The Extended Particle Difference Method is developed for interfacial singularity problems based on the Extended Particle Derivative Approximation scheme. Node-wise strong formulations are adopted for transient heat transfer problems, potential problems, and elasticity problems with various interfacial boundaries. The governing partial differential equations are directly discretized at interior and boundary nodes and the interface condition is immersed in the derivative approximation or is enforced at interfacial points. Assemblage of the discretized equations generates a linear algebraic system of equations, which accelerates computation speed due to the avoidance of numerical integration. Solving the system gives the nodal solution together with the jump solutions. We also demonstrate the robustness and effectiveness of the developed method with various numerical examples. Despite the existence of the singularity in the solution fields, the method overcomes the geometrical complexity inherent in interface modeling and thus achieves the second-order accuracy.

  12. Party package travel: alcohol use and related problems in a holiday resort: a mixed methods study

    PubMed Central

    Hesse, Morten; Tutenges, Sébastien; Schliewe, Sanna; Reinholdt, Tine

    2008-01-01

    Background People travelling abroad tend to increase their use of alcohol and other drugs. In the present study we describe organized party activities in connection with young tourists' drinking, and the differences between young people travelling with and without organized party activities. Methods We conducted ethnographic observations and a cross-sectional survey in Sunny Beach, Bulgaria. Results The behaviour of the guides from two travel agencies strongly promoted heavy drinking, but discouraged illicit drug use. Even after controlling for several potential confounders, young people who travelled with such "party package travel agencies" were more likely to drink 12 or more units when going out. In univariate analyses, they were also more likely to get into fights, but were not more likely to seek medical assistance or medical assistance for an accident or an alcohol-related problem. After controlling for confounders, the association between type of travel agency and getting into fights was no longer significant. Short-term consequences of drinking in the holiday resort did not differ between party package travellers and ordinary package travellers. Conclusion There may be a small impact of party package travels on young people's drinking. Strategies could be developed used to minimise the harm associated with both party package travel and other kinds of travel where heavy substance use is likely to occur. PMID:18840273

  13. A Simplified Method for Routine Outcome Monitoring after Drug Abuse Treatment

    PubMed Central

    Lennox, Richard D.; Sternquist, Marie A.; Paredes, Alfonso

    2013-01-01

    The routine collection of drug treatment outcomes to manage quality of care, improve patient satisfaction, and allocate treatment resources is currently hampered by two key difficulties: (1) problems locating clients once they leave treatment; and (2) the prohibitive cost of obtaining meaningful and reliable post-treatment data. This pilot describes precise methods for an economical staff-based routine outcome monitoring (ROM) system using an 18-item core measure telephone survey. As implemented at Narconon™ of Oklahoma, a behavioral and social skills based, residential drug rehabilitation program, the system was psychometrically adequate for aggregate reporting while providing clinically useful information. Standardized procedures for staff training, collecting client contact information, structuring exit interviews and maintaining post-treatment telephone contact produced follow-up rates that improved from 57.6% to 100% over the course of the project. Aggregate data was used to improve program delivery and thereby post-treatment substance use and social outcomes. These methods and use of data may contribute to the discussion on how to best monitor outcomes. PMID:24092985

  14. Suggested Activities on Sociological Health Problems: Drugs, Alcoholism, Smoking for Student Teachers.

    ERIC Educational Resources Information Center

    Samalonis, Bernice

    This is a list of recommendations for a neophyte teacher for discussions with students on drugs, alcoholism, and smoking. Included are suggested readings, suggested questions for the school's drug education coordinator, recommended readings, and New York sources of information. (Related document is SP 006 468.) (JA)

  15. Fast marching methods for the continuous traveling salesman problem

    SciTech Connect

    Andrews, J.; Sethian, J.A.

    2008-12-01

    We consider a problem in which we are given a domain, a cost function which depends on position at each point in the domain, and a subset of points ('cities') in the domain. The goal is to determine the cheapest closed path that visits each city in the domain once. This can be thought of as a version of the Traveling Salesman Problem, in which an underlying known metric determines the cost of moving through each point of the domain, but in which the actual shortest path between cities is unknown at the outset. We describe algorithms for both a heuristic and an optimal solution to this problem. The order of the heuristic algorithm is at worst case M * N logN, where M is the number of cities, and N the size of the computational mesh used to approximate the solutions to the shortest paths problems. The average runtime of the heuristic algorithm is linear in the number of cities and O(N log N) in the size N of the mesh.

  16. Analysis of an Assessment Method for Problem-Based Learning

    ERIC Educational Resources Information Center

    Acar, B. Serpil

    2004-01-01

    The paper commences by briefly introducing the systems engineering programme, then focuses on the "systems" module, which requires the first-year students to undertake a number of "open-ended" projects. During the problem-based learning (PBL) based projects the students are expected to combine creativity and the knowledge they acquire during the…

  17. Tracing Success: Graphical Methods for Analysing Successful Collaborative Problem Solving

    ERIC Educational Resources Information Center

    Joiner, Richard; Issroff, Kim

    2003-01-01

    The aim of this paper is to evaluate the use of trace diagrams for analysing collaborative problem solving. The paper describes a study where trace diagrams were used to analyse joint navigation in a virtual environment. Ten pairs of undergraduates worked together on a distributed virtual task to collect five flowers using two bees with each…

  18. Real time monitoring of drug action on T. cruzi parasites using a biospeckle laser method

    NASA Astrophysics Data System (ADS)

    Ansari, M. Z.; Grassi, H. C.; Cabrera, H.; Andrades, E. D. J.

    2016-06-01

    In this paper, we report on a biospeckle laser method used to monitor a specific drug action on T. cruzi parasites. Experimental results from fast biospeckle monitoring of the parasites’ activity under the influence of the drug demonstrate the effectiveness of the proposed method. We measure the speckle parameters such as spatiotemporal correlation and speckle grain size to assess the immediate action of the drug on the parasites during a very short incubation period. From a practical point of view, this aproach allows us to validate biospeckle as a fast, non-invasive and alternative method to test candidate drugs on T. cruzi parasites.

  19. Modern Methods for Analysis of Antiepileptic Drugs in the Biological Fluids for Pharmacokinetics, Bioequivalence and Therapeutic Drug Monitoring

    PubMed Central

    Park, Yoo-Sin; Kim, Shin-Hee; Kim, Sang-Hyun; Jun, Min-Young

    2011-01-01

    Epilepsy is a chronic disease occurring in approximately 1.0% of the world's population. About 30% of the epileptic patients treated with availably antiepileptic drugs (AEDs) continue to have seizures and are considered therapy-resistant or refractory patients. The ultimate goal for the use of AEDs is complete cessation of seizures without side effects. Because of a narrow therapeutic index of AEDs, a complete understanding of its clinical pharmacokinetics is essential for understanding of the pharmacodynamics of these drugs. These drug concentrations in biological fluids serve as surrogate markers and can be used to guide or target drug dosing. Because early studies demonstrated clinical and/or electroencephalographic correlations with serum concentrations of several AEDs, It has been almost 50 years since clinicians started using plasma concentrations of AEDs to optimize pharmacotherapy in patients with epilepsy. Therefore, validated analytical method for concentrations of AEDs in biological fluids is a necessity in order to explore pharmacokinetics, bioequivalence and TDM in various clinical situations. There are hundreds of published articles on the analysis of specific AEDs by a wide variety of analytical methods in biological samples have appears over the past decade. This review intends to provide an updated, concise overview on the modern method development for monitoring AEDs for pharmacokinetic studies, bioequivalence and therapeutic drug monitoring. PMID:21660146

  20. Validity Evidence for FASTHUG-MAIDENS, a Mnemonic for Identifying Drug-Related Problems in the Intensive Care Unit

    PubMed Central

    Masson, Sarah C; Mabasa, Vincent H; Malyuk, Douglas L; Perrott, Jerrold L

    2013-01-01

    Background The mnemonic FASTHUG (Feeding, Analgesia, Sedation, Thromboembolic prophylaxis, Head of bed elevation, stress Ulcer prophylaxis, Glucose control) was developed by intensive care unit (ICU) physicians to ensure that key aspects of care are addressed during each patient encounter. Because this tool does not specifically target pharmacotherapy assessments, a modified version, FASTHUG-MAIDENS, was created, by changing the H to mean Hypoactive or Hyperactive delirium and adding M for Medication reconciliation; A for Antibiotics or Anti-infectives; I for Indications for medications; D for drug Dosing; E for Electrolytes, hematology, and other laboratory tests; N for No drug interactions, allergies, duplication, or side effects; and S for Stop dates. Objective: To validate the use of FASTHUG-MAIDENS as a tool for identifying drug-related problems (DRPs) in the ICU. Methods: This randomized, prospective validation study took place between January and May 2011 in the ICUs of 4 hospitals: 2 community-level ICUs and 2 tertiary referral ICUs. Each ICU had a dedicated ICU pharmacist and one or more pharmacy residents completing an ICU rotation as part of their pharmacy practice residency (total of 6 residents). The 6 pharmacy residents were randomly assigned to assess patients admitted to the ICU using FASTHUG-MAIDENS or standard monitoring practice. The mean proportion of DRPs per patient encounter identified by the residents (relative to DRPs identified by the ICU pharmacists) was the primary outcome, and the proportion of total DRPs identified in each group was assessed as a secondary end point. Results: Pharmacy residents using the FASTHUG-MAIDENS mnemonic identified a significantly greater mean proportion of DRPs per patient encounter (73.2% versus 52.4%, p = 0.008) and a greater proportion of total DRPs (77.1% versus 52.5%, p < 0.001) than those assessing patients according to standard monitoring practice. Conclusion: In this sample, the mnemonic FASTHUG

  1. Drug name recognition in biomedical texts: a machine-learning-based method.

    PubMed

    He, Linna; Yang, Zhihao; Lin, Hongfei; Li, Yanpeng

    2014-05-01

    Currently, there is an urgent need to develop a technology for extracting drug information automatically from biomedical texts, and drug name recognition is an essential prerequisite for extracting drug information. This article presents a machine-learning-based approach to recognize drug names in biomedical texts. In this approach, a drug name dictionary is first constructed with the external resource of DrugBank and PubMed. Then a semi-supervised learning method, feature coupling generalization, is used to filter this dictionary. Finally, the dictionary look-up and the condition random field method are combined to recognize drug names. Experimental results show that our approach achieves an F-score of 92.54% on the test set of DDIExtraction2011. PMID:24140287

  2. A Rapid and Quantitative Fluorimetric Method for Protein-Targeting Small Molecule Drug Screening.

    PubMed

    Yu, Yong; New, Siu Yee; Lin, Jiaxian; Su, Xiaodi; Tan, Yen Nee

    2015-01-01

    We demonstrate a new drug screening method for determining the binding affinity of small drug molecules to a target protein by forming fluorescent gold nanoclusters (Au NCs) within the drug-loaded protein, based on the differential fluorescence signal emitted by the Au NCs. Albumin proteins such as human serum albumin (HSA) and bovine serum albumin (BSA) are selected as the model proteins. Four small molecular drugs (e.g., ibuprofen, warfarin, phenytoin, and sulfanilamide) of different binding affinities to the albumin proteins are tested. It was found that the formation rate of fluorescent Au NCs inside the drug loaded albumin protein under denaturing conditions (i.e., 60 °C or in the presence of urea) is slower than that formed in the pristine protein (without drugs). Moreover, the fluorescent intensity of the as-formed NCs is found to be inversely correlated to the binding affinities of these drugs to the albumin proteins. Particularly, the higher the drug-protein binding affinity, the slower the rate of Au NCs formation, and thus a lower fluorescence intensity of the resultant Au NCs is observed. The fluorescence intensity of the resultant Au NCs therefore provides a simple measure of the relative binding strength of different drugs tested. This method is also extendable to measure the specific drug-protein binding constant (KD) by simply varying the drug content preloaded in the protein at a fixed protein concentration. The measured results match well with the values obtained using other prestige but more complicated methods. PMID:26555855

  3. Problem drug use prevalence estimation revisited: heterogeneity in capture–recapture and the role of external evidence

    PubMed Central

    Welton, Nicky J.; Ades, A. E.; Pierce, Matthias; Davies, Wyn; Coleman, Barbara; Millar, Tim; Hickman, Matthew

    2016-01-01

    Abstract Background and Aims Capture–recapture (CRC) analysis is recommended for estimating the prevalence of problem drug use or people who inject drugs (PWID). We aim to demonstrate how naive application of CRC can lead to highly misleading results, and to suggest how the problems might be overcome. Methods We present a case study of estimating the prevalence of PWID in Bristol, UK, applying CRC to lists in contact with three services. We assess: (i) sensitivity of results to different versions of the dominant (treatment) list: specifically, to inclusion of non‐incident cases and of those who were referred directly from one of the other services; (ii) the impact of accounting for a novel covariate, housing instability; and (iii) consistency of CRC estimates with drug‐related mortality data. We then incorporate formally the drug‐related mortality data and lower bounds for prevalence alongside the CRC into a single coherent model. Results Five of 11 models fitted the full data equally well but generated widely varying prevalence estimates, from 2740 [95% confidence interval (CI) = 2670, 2840] to 6890 (95% CI = 3740, 17680). Results were highly sensitive to inclusion of non‐incident cases, demonstrating the presence of considerable heterogeneity, and were sensitive to a lesser extent to inclusion of direct referrals. A reduced data set including only incident cases and excluding referrals could be fitted by simpler models, and led to much greater consistency in estimates. Accounting for housing stability improved model fit considerably more than did the standard covariates of age and gender. External data provided validation of results and aided model selection, generating a final estimate of the number of PWID in Bristol in 2011 of 2770 [95% credible interval (Cr‐I) = 2570, 3110] or 0.9% (95% Cr‐I = 0.9, 1.0%) of the population aged 15–64 years. Conclusions Steps can be taken to reduce bias in capture–recapture analysis, including: careful

  4. A Prospective Method to Guide Small Molecule Drug Design

    ERIC Educational Resources Information Center

    Johnson, Alan T.

    2015-01-01

    At present, small molecule drug design follows a retrospective path when considering what analogs are to be made around a current hit or lead molecule with the focus often on identifying a compound with higher intrinsic potency. What this approach overlooks is the simultaneous need to also improve the physicochemical (PC) and pharmacokinetic (PK)…

  5. Assessing Student Pharmacists’ Ability to Identify Drug-Related Problems in Patients Within a Patient-Centered Medical Home

    PubMed Central

    Bulkley, Christina F.; Truong, Teresa; Carter, Sandra M.

    2014-01-01

    Objective. To quantify, describe, and categorize patient drug-related problems (DRPs) and recommendations identified by fourth-year (P4) student pharmacists during a live medication reconciliation activity within a patient-centered medical home (PCMH). Methods. Fourth-year student pharmacists conducted chart reviews, identified and documented DRPs, obtained live medication histories, and immediately provided findings and recommendations to the attending physicians. Documentation of DRPs and recommendations were analyzed retrospectively. Results. Thirty-eight students completed 99 medication reconciliation sessions from June 2011 to October 2012 during their advanced pharmacy practice experience (APPE). The students obtained 676 patient medication histories and identified or intervened on 1308 DRPs. The most common DRPs reported were incomplete medication list and diagnostic/laboratory testing needed. Physicians accepted 1,018 (approximately 78%) recommendations. Conclusion. Student pharmacists successfully identified and reduced DRPs through a live medication reconciliation process within an academic-based PCMH model. Their medication history-taking skills improved and medication use was optimized. PMID:24558274

  6. Classification of drug molecules considering their IC50 values using mixed-integer linear programming based hyper-boxes method

    PubMed Central

    Armutlu, Pelin; Ozdemir, Muhittin E; Uney-Yuksektepe, Fadime; Kavakli, I Halil; Turkay, Metin

    2008-01-01

    Background A priori analysis of the activity of drugs on the target protein by computational approaches can be useful in narrowing down drug candidates for further experimental tests. Currently, there are a large number of computational methods that predict the activity of drugs on proteins. In this study, we approach the activity prediction problem as a classification problem and, we aim to improve the classification accuracy by introducing an algorithm that combines partial least squares regression with mixed-integer programming based hyper-boxes classification method, where drug molecules are classified as low active or high active regarding their binding activity (IC50 values) on target proteins. We also aim to determine the most significant molecular descriptors for the drug molecules. Results We first apply our approach by analyzing the activities of widely known inhibitor datasets including Acetylcholinesterase (ACHE), Benzodiazepine Receptor (BZR), Dihydrofolate Reductase (DHFR), Cyclooxygenase-2 (COX-2) with known IC50 values. The results at this stage proved that our approach consistently gives better classification accuracies compared to 63 other reported classification methods such as SVM, Naïve Bayes, where we were able to predict the experimentally determined IC50 values with a worst case accuracy of 96%. To further test applicability of this approach we first created dataset for Cytochrome P450 C17 inhibitors and then predicted their activities with 100% accuracy. Conclusion Our results indicate that this approach can be utilized to predict the inhibitory effects of inhibitors based on their molecular descriptors. This approach will not only enhance drug discovery process, but also save time and resources committed. PMID:18834515

  7. Solution of elastoplastic torsion problem by boundary integral method

    NASA Technical Reports Server (NTRS)

    Mendelson, A.

    1975-01-01

    The boundary integral method was applied to the elastoplastic analysis of the torsion of prismatic bars, and the results are compared with those obtained by the finite difference method. Although fewer unknowns were used, very good accuracy was obtained with the boundary integral method. Both simply and multiply connected bodies can be handled with equal ease.

  8. Chebyshev moment problems: Maximum entropy and kernel polynomial methods

    SciTech Connect

    Silver, R.N.; Roeder, H.; Voter, A.F.; Kress, J.D.

    1995-12-31

    Two Chebyshev recursion methods are presented for calculations with very large sparse Hamiltonians, the kernel polynomial method (KPM) and the maximum entropy method (MEM). They are applicable to physical properties involving large numbers of eigenstates such as densities of states, spectral functions, thermodynamics, total energies for Monte Carlo simulations and forces for tight binding molecular dynamics. this paper emphasizes efficient algorithms.

  9. Street Drugs and Pregnancy

    MedlinePlus

    ... drugs that are abused How can street drugs harm your pregnancy? Using street drugs can cause problems ... drugs that are abused How can street drugs harm your pregnancy? Using street drugs can cause problems ...

  10. Methods for trend analysis: Examples with problem/failure data

    NASA Technical Reports Server (NTRS)

    Church, Curtis K.

    1989-01-01

    Statistics are emphasized as an important role in quality control and reliability. Consequently, Trend Analysis Techniques recommended a variety of statistical methodologies that could be applied to time series data. The major goal of the working handbook, using data from the MSFC Problem Assessment System, is to illustrate some of the techniques in the NASA standard, some different techniques, and to notice patterns of data. Techniques for trend estimation used are: regression (exponential, power, reciprocal, straight line) and Kendall's rank correlation coefficient. The important details of a statistical strategy for estimating a trend component are covered in the examples. However, careful analysis and interpretation is necessary because of small samples and frequent zero problem reports in a given time period. Further investigations to deal with these issues are being conducted.

  11. Application of traditional CFD methods to nonlinear computational aeroacoustics problems

    NASA Technical Reports Server (NTRS)

    Chyczewski, Thomas S.; Long, Lyle N.

    1995-01-01

    This paper describes an implementation of a high order finite difference technique and its application to the category 2 problems of the ICASE/LaRC Workshop on Computational Aeroacoustics (CAA). Essentially, a popular Computational Fluid Dynamics (CFD) approach (central differencing, Runge-Kutta time integration and artificial dissipation) is modified to handle aeroacoustic problems. The changes include increasing the order of the spatial differencing to sixth order and modifying the artificial dissipation so that it does not significantly contaminate the wave solution. All of the results were obtained from the CM5 located at the Numerical Aerodynamic Simulation Laboratory. lt was coded in CMFortran (very similar to HPF), using programming techniques developed for communication intensive large stencils, and ran very efficiently.

  12. Petri Net Modeling and Decomposition Method for Solving Production Scheduling Problems

    NASA Astrophysics Data System (ADS)

    Nishi, Tatsushi; Maeno, Ryota

    Considering the need to develop general scheduling problem solver, the recent integration of Petri Nets as modeling tools into effective optimization methods for scheduling problems is very promising. The paper addresses a Petri Net modeling and decomposition method for solving a wide variety of scheduling problems. The scheduling problems are represented as the optimal transition firing sequence problems for timed Petri Nets. The Petri Net is decomposed into several subnets in which each subproblem can be easily solved by Dijkstra' algorithm. The approach is applied to a flowshop scheduling problem. The performance of the proposed algorithm is compared with that of a simulated annealing method.

  13. Drug-specific in vitro secretion of IFNγ in the diagnosis of drug-induced exanthemas: electrochemiluminescence assay versus previously used diagnostic methods.

    PubMed

    Porebski, Grzegorz; Czarnobilska, Ewa

    2015-01-01

    The in vitro diagnosis of delayed drug hypersensitivity reactions remains a research problem. We measured drug-specific IFNγ release in peripheral blood mononuclear cells sampled from patients with drug-induced maculopapular exanthema and the age- and sex-matched control group. This is the first study to directly cross-compare an ultrasensitive assay based on an emerging electrochemiluminescence technology (ECL), the standard lymphocyte proliferation assay and three following tests detecting IFNγ at different steps of its production: intracellular in CD3+CD4+ cells (flow cytometry), secretion at the single cell level (enzyme-linked immunospot assay), bulk content in cell culture supernatant (enzyme-linked immunosorbent assay, ELISA). The highest rate of drug-positive responses were recorded for ELISA and ECL tests (56.25%). No false-positive responses were observed--all tests were negative in the control group. We demonstrated that IFNγ-detecting ELISA is not less efficient than ECL test, however, it is easily available and cheap, which makes it a potential method of choice in the future. PMID:27024947

  14. Mixed Methods Research: The "Thing-ness" Problem.

    PubMed

    Hesse-Biber, Sharlene

    2015-06-01

    Contemporary mixed methods research (MMR) veers away from a "loosely bounded" to a "bounded" concept that has important negative implications for how qualitatively driven mixed methods approaches are positioned in the field of mixed methods and overall innovation in the praxis of MMR. I deploy the concept of reification defined as taking an object/abstraction and treating it as if it were real such that it takes on the quality of "thing-ness," having a concrete independent existence. I argue that the contemporary reification of mixed methods as a "thing" is fueled by three interrelated factors: (a) the growing formalization of mixed methods as design, (b) the unexamined belief in the "synergy" of mixed methods and, (c) the deployment of a "practical pragmatism" as the "philosophical partner" for mixed methods inquiry. PMID:25888694

  15. Factors associated with serum retinol, x-tocopherol, carotenoids, and selenium in Hispanics with problems of HIV, chornis hepatitis, chronic hepatitis C, and drug use

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of hepatitis and drug use on nutritional problems in HIV infection have rarely been examined despite the importance of drug use in the global HIV pandemic. We examined the effects of HIV, hepatitis C, and drug use on serum micronutrients in 300 US Hispanic adults. Chronic hepatitis C inf...

  16. Use of a problem-based learning exercise to teach the lean 8-step problem-solving method.

    PubMed

    Tovar, Elizabeth G; Warshawsky, Nora

    2015-01-01

    Doctor of nursing practice (DNP) graduates must be prepared to lead quality improvement (QI) initiatives in health care settings; however, effective and feasible teaching strategies pose a challenge for many DNP program faculties. This article describes a successful and practical problem-based learning exercise for students to work through the QI process using the Lean 8-step problem-solving method. Suggestions for faculty and recommendations for future activities are discussed. PMID:25695501

  17. Application of the FETI Method to ASCI Problems: Scalability Results on One Thousand Processors and Discussion of Highly Heterogeneous Problems

    SciTech Connect

    Bhardwaj, M.; Day, D.; Farhat, C.; Lesoinne, M; Pierson, K.; Rixen, D.

    1999-04-01

    We report on the application of the one-level FETI method to the solution of a class of substructural problems associated with the Department of Energy's Accelerated Strategic Computing Initiative (ASCI). We focus on numerical and parallel scalability issues, and on preliminary performance results obtained on the ASCI Option Red supercomputer configured with as many as one thousand processors, for problems with as many as 5 million degrees of freedom.

  18. Prosecution's Power, Procedural Rights, and Pleading Guilty: The Problem of Coercion in Plea Bargaining Drug Cases.

    ERIC Educational Resources Information Center

    Cloyd, Jerald W.

    1979-01-01

    The forms of psychological pressure placed on the defendant's pleading in drug cases are examined, with emphasis on the interplay between rational and emotional aspects of such situations. Three stages in plea bargaining negotiations are outlined. (Author/MC)

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

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... cause a drug test to be cancelled? (a) As the MRO, when the laboratory discovers a “fatal flaw” during...) The following are “fatal flaws”: (1) There is no printed collector's name and no collector's...

  20. 49 CFR 40.199 - What problems always cause a drug test to be cancelled?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... cause a drug test to be cancelled? (a) As the MRO, when the laboratory discovers a “fatal flaw” during...) The following are “fatal flaws”: (1) There is no printed collector's name and no collector's...

  1. 49 CFR 40.199 - What problems always cause a drug test to be cancelled?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... cause a drug test to be cancelled? (a) As the MRO, when the laboratory discovers a “fatal flaw” during...) The following are “fatal flaws”: (1) There is no printed collector's name and no collector's...

  2. A network centrality method for the rating problem.

    PubMed

    Li, Yongli; Pin, Paolo; Wu, Chong

    2015-01-01

    We propose a new method for aggregating the information of multiple users rating multiple items. Our approach is based on the network relations induced between items by the rating activity of the users. Our method correlates better than the simple average with respect to the original rankings of the users, and besides, it is computationally more efficient than other methods proposed in the literature. Moreover, our method is able to discount the information that would be obtained adding to the system additional users with a systematically biased rating activity. PMID:25830502

  3. A Network Centrality Method for the Rating Problem

    PubMed Central

    2015-01-01

    We propose a new method for aggregating the information of multiple users rating multiple items. Our approach is based on the network relations induced between items by the rating activity of the users. Our method correlates better than the simple average with respect to the original rankings of the users, and besides, it is computationally more efficient than other methods proposed in the literature. Moreover, our method is able to discount the information that would be obtained adding to the system additional users with a systematically biased rating activity. PMID:25830502

  4. Solution of facility location problem in Turkey by using fuzzy C-means method

    NASA Astrophysics Data System (ADS)

    Kocakaya, Mustafa Nabi; Türkakın, Osman Hürol

    2013-10-01

    Facility location problem is one of most frequent problems, which is encountered while deciding facility places such as factories, warehouses. There are various techniques developed to solve facility location problems. Fuzzy c-means method is one of the most usable techniques between them. In this study, optimum warehouse location for natural stone mines is found by using fuzzy c-means method.

  5. Drug Ingestions in Children 10-14 Years Old: An Old Problem Revisited

    ERIC Educational Resources Information Center

    Pomerantz, Wendy; Gittelman, Michael; Farris, Sarah; Frey, Lauren

    2009-01-01

    To determine changes in rates of drug ingestions in 10-14 year old children in our country, a retrospective chart review of 10-14 year olds hospitalized for drug ingestion between 1993-1995 and 2000-2004 was performed. Odds ratios and Chi-square were used for analyses. From 1993-1995 there were 92.8 ingestions/100,000 children/year; from 2000-2004…

  6. Alcohol and drug use among adolescents: and the co-occurrence of mental health problems. Ung@hordaland, a population-based study

    PubMed Central

    Skogen, Jens Christoffer; Sivertsen, Børge; Lundervold, Astri J; Stormark, Kjell Morten; Jakobsen, Reidar; Hysing, Mari

    2014-01-01

    Objectives The use of alcohol and drugs is prevalent among adolescents, but too little is known about the association between debut of alcohol and drug use, problematic use and concurrent mental health. The aim of the study was to investigate the cross-sectional association between debut of any alcohol or drug use and alcohol-related and drug-related problems and mental health. We also wanted to examine potential interactions between gender and age, and alcohol-related and drug-related variables. Design Cross-sectional study. Setting Population-based sample of Norwegian adolescents. Participants Data stem from the large population-based ung@hordaland study (N=9203), where all adolescents aged 17–19 years living in Hordaland county (Norway) were invited to participate. The main independent variables were debut of alcohol and drug use, alcohol consumption and the presence of alcohol and drug problems as measured by CRAFFT. Outcomes The dependent variables were self-reported symptoms of anxiety, depression, inattention and hyperactivity. Statistical analyses included logistic regression models. Results Debut of alcohol and drug use were associated with symptoms of depression, inattention and hyperactivity (crude ORs 1.69–2.38, p<0.001), while only debut of drug use was associated with increased symptoms of anxiety (OR=1.33, CI 95% 1.05 to 1.68, p=0.017). Alcohol-related and drug-related problems as measured by CRAFFT were associated with all mental health problems (crude ORs 1.68–3.24, p<0.001). There was little evidence of any substantial age or gender confounding on the estimated associations between alcohol-related and drug-related measures and mental health problems. Conclusions Early debut of alcohol and drug use and drug problems is consistently associated with more symptoms of mental health problems, indicating that these factors are an important general indicator of mental health in adolescence. PMID:25245403

  7. Solution methods for one-dimensional viscoelastic problems

    NASA Technical Reports Server (NTRS)

    Stubstad, John M.; Simitses, George J.

    1987-01-01

    A recently developed differential methodology for solution of one-dimensional nonlinear viscoelastic problems is presented. Using the example of an eccentrically loaded cantilever beam-column, the results from the differential formulation are compared to results generated using a previously published integral solution technique. It is shown that the results obtained from these distinct methodologies exhibit a surprisingly high degree of correlation with one another. A discussion of the various factors affecting the numerical accuracy and rate of convergence of these two procedures is also included. Finally, the influences of some 'higher order' effects, such as straining along the centroidal axis are discussed.

  8. A review of some radiometric calibration problems and methods

    NASA Technical Reports Server (NTRS)

    Slater, P. N.

    1984-01-01

    The in-flight radiometric calibration instrumentation and procedures of the Landsat Thematic Mapper and the high-resolution visible-range instruments of SPOT are illustrated with drawings and diagrams, characterized, and compared. Problems encountered in the laboratory calibration process, minimizing the temporal instability of the systems, identifying anomalies in the electronics in flight, and rechecking the calibration are examined, and it is pointed out that the stability of the calibration systems is less than that of the instruments themselves. The use of carefully measured ground-site data and atmospheric parameters in combination with radiative-transfer models for periodic calibration is recommended.

  9. Problems with the differential receiver operating characteristic (DROC) method

    NASA Astrophysics Data System (ADS)

    Chakraborty, Dev P.

    2004-05-01

    Most papers in these proceedings present ideas that work. This is the story of an idea that did not work as intended. The differential receiver operating characteristic (DROC) method was proposed about 8 years ago. It was intended to measure the difference in performance between two imaging modalities. It was expected that the DROC method could outperform the ROC method in statistical power. This expectation has not been borne out and the author no longer recommends the DROC method. The purpose of this paper is to present a critical look at this method, why the author initially believed it should work, the assumptions involved and the fallacies. The author believes there is value to this frank account as it has yielded, at least for the author, new insights into ROC analysis. The author concludes with a few personal reflections on his experience with this project and advice on how to deal with negative results.

  10. Method effects: the problem with negatively versus positively keyed items.

    PubMed

    Lindwall, Magnus; Barkoukis, Vassilis; Grano, Caterina; Lucidi, Fabio; Raudsepp, Lennart; Liukkonen, Jarmo; Thøgersen-Ntoumani, Cecilie

    2012-01-01

    Using confirmatory factor analyses, we examined method effects on Rosenberg's Self-Esteem Scale (RSES; Rosenberg, 1965) in a sample of older European adults. Nine hundred forty nine community-dwelling adults 60 years of age or older from 5 European countries completed the RSES as well as measures of depression and life satisfaction. The 2 models that had an acceptable fit with the data included method effects. The method effects were associated with both positively and negatively worded items. Method effects models were invariant across gender and age, but not across countries. Both depression and life satisfaction predicted method effects. Individuals with higher depression scores and lower life satisfaction scores were more likely to endorse negatively phrased items. PMID:22339312

  11. Numerical Solutions of Electromagnetic Problems by Integral Equation Methods and Finite-Difference Time - Method.

    NASA Astrophysics Data System (ADS)

    Min, Xiaoyi

    This thesis first presents the study of the interaction of electromagnetic waves with three-dimensional heterogeneous, dielectric, magnetic, and lossy bodies by surface integral equation modeling. Based on the equivalence principle, a set of coupled surface integral equations is formulated and then solved numerically by the method of moments. Triangular elements are used to model the interfaces of the heterogeneous body, and vector basis functions are defined to expand the unknown current in the formulation. The validity of this formulation is verified by applying it to concentric spheres for which an exact solution exists. The potential applications of this formulation to a partially coated sphere and a homogeneous human body are discussed. Next, this thesis also introduces an efficient new set of integral equations for treating the scattering problem of a perfectly conducting body coated with a thin magnetically lossy layer. These electric field integral equations and magnetic field integral equations are numerically solved by the method of moments (MoM). To validate the derived integral equations, an alternative method to solve the scattering problem of an infinite circular cylinder coated with a thin magnetic lossy layer has also been developed, based on the eigenmode expansion. Results for the radar cross section and current densities via the MoM and the eigenmode expansion method are compared. The agreement is excellent. The finite difference time domain method is subsequently implemented to solve a metallic object coated with a magnetic thin layer and numerical results are compared with that by the MoM. Finally, this thesis presents an application of the finite-difference time-domain approach to the problem of electromagnetic receiving and scattering by a cavity -backed antenna situated on an infinite conducting plane. This application involves modifications of Yee's model, which applies the difference approximations of field derivatives to differential

  12. An Efficient Optimization Method for Solving Unsupervised Data Classification Problems

    PubMed Central

    Shabanzadeh, Parvaneh; Yusof, Rubiyah

    2015-01-01

    Unsupervised data classification (or clustering) analysis is one of the most useful tools and a descriptive task in data mining that seeks to classify homogeneous groups of objects based on similarity and is used in many medical disciplines and various applications. In general, there is no single algorithm that is suitable for all types of data, conditions, and applications. Each algorithm has its own advantages, limitations, and deficiencies. Hence, research for novel and effective approaches for unsupervised data classification is still active. In this paper a heuristic algorithm, Biogeography-Based Optimization (BBO) algorithm, was adapted for data clustering problems by modifying the main operators of BBO algorithm, which is inspired from the natural biogeography distribution of different species. Similar to other population-based algorithms, BBO algorithm starts with an initial population of candidate solutions to an optimization problem and an objective function that is calculated for them. To evaluate the performance of the proposed algorithm assessment was carried on six medical and real life datasets and was compared with eight well known and recent unsupervised data classification algorithms. Numerical results demonstrate that the proposed evolutionary optimization algorithm is efficient for unsupervised data classification. PMID:26336509

  13. An Efficient Optimization Method for Solving Unsupervised Data Classification Problems.

    PubMed

    Shabanzadeh, Parvaneh; Yusof, Rubiyah

    2015-01-01

    Unsupervised data classification (or clustering) analysis is one of the most useful tools and a descriptive task in data mining that seeks to classify homogeneous groups of objects based on similarity and is used in many medical disciplines and various applications. In general, there is no single algorithm that is suitable for all types of data, conditions, and applications. Each algorithm has its own advantages, limitations, and deficiencies. Hence, research for novel and effective approaches for unsupervised data classification is still active. In this paper a heuristic algorithm, Biogeography-Based Optimization (BBO) algorithm, was adapted for data clustering problems by modifying the main operators of BBO algorithm, which is inspired from the natural biogeography distribution of different species. Similar to other population-based algorithms, BBO algorithm starts with an initial population of candidate solutions to an optimization problem and an objective function that is calculated for them. To evaluate the performance of the proposed algorithm assessment was carried on six medical and real life datasets and was compared with eight well known and recent unsupervised data classification algorithms. Numerical results demonstrate that the proposed evolutionary optimization algorithm is efficient for unsupervised data classification. PMID:26336509

  14. Computational methods for the problems of the tip vortex

    NASA Technical Reports Server (NTRS)

    Garabedian, Paul R.

    1988-01-01

    The tip vortex problem for helicopter rotors in transonic flow was studied. The first model was that of potential flow past a single blade in parallel transonic flow. The incidence on the wing of a vortex sheet trailing from a blade in front was studied by modeling the incident sheet by a single vortex filament. A 3-D potential flow code was written to incorporate the usual boundary conditions at infinity together with the model of such a vortex filament and to analyze the resulting flow over the wing. The code was used to study the effect of the vortex filament on the production of shocks at the tip of the wing. Another problem studied within the framework of potential flow theory was the rollup of the vortex sheet behind the wing. A comparison was made of flow models described by the potential equation, by the Euler equations for steady flow, and by the Navier-Stokes equations. The question was also studied as to whether there is an advantage in solving the Navier-Stokes equations rather than the Euler equations for steady flow.

  15. Methods for the Detection of Drugs of Abuse in Body Fluids: An Overview. Series 24, No.1.

    ERIC Educational Resources Information Center

    National Inst. on Drug Abuse (DHEW/PHS), Rockville, MD. National Clearinghouse for Drug Abuse Information.

    The increasing use and abuse of a variety of drugs have resulted in the nationwide growth of many programs for the detection and treatment of drug abuse. The purpose of developing drug detection methods has been to provide physicians, therapists, and others involved with drug users an objective means to determine and measure drug usage. This…

  16. A numerical method for eigenvalue problems in modeling liquid crystals

    SciTech Connect

    Baglama, J.; Farrell, P.A.; Reichel, L.; Ruttan, A.; Calvetti, D.

    1996-12-31

    Equilibrium configurations of liquid crystals in finite containments are minimizers of the thermodynamic free energy of the system. It is important to be able to track the equilibrium configurations as the temperature of the liquid crystals decreases. The path of the minimal energy configuration at bifurcation points can be computed from the null space of a large sparse symmetric matrix. We describe a new variant of the implicitly restarted Lanczos method that is well suited for the computation of extreme eigenvalues of a large sparse symmetric matrix, and we use this method to determine the desired null space. Our implicitly restarted Lanczos method determines adoptively a polynomial filter by using Leja shifts, and does not require factorization of the matrix. The storage requirement of the method is small, and this makes it attractive to use for the present application.

  17. Problems d'elaboration d'une methode locale: la methode "Paris-Khartoum" (Problems in Implementing a Local Method: the Paris-Khartoum Method)

    ERIC Educational Resources Information Center

    Penhoat, Loick; Sakow, Kostia

    1978-01-01

    A description of the development and implementation of a method introduced in the Sudan that attempts to relate to Sudanese culture and to motivate students. The relationship between language teaching methods and the total educational system is discussed. (AMH)

  18. Qualitative and quantitative methods to determine miscibility in amorphous drug-polymer systems.

    PubMed

    Meng, Fan; Dave, Vivek; Chauhan, Harsh

    2015-09-18

    Amorphous drug-polymer systems or amorphous solid dispersions are commonly used in pharmaceutical industry to enhance the solubility of compounds with poor aqueous solubility. The degree of miscibility between drug and polymer is important both for solubility enhancement as well as for the formation of a physically stable amorphous system. Calculation of solubility parameters, Computational data mining, Tg measurements by DSC and Raman mapping are established traditional methods used to qualitatively detect the drug-polymer miscibility. Calculation of Flory-Huggins interaction parameter, computational analysis of X-Ray Diffraction (XRD) data, solid state Nuclear Magnetic Resonance (NMR) spectroscopy and Atomic Forced Microscopy (AFM) have been recently developed to quantitatively determine the miscibility in amorphous drug-polymer systems. This brief review introduces and compiles these qualitative and quantitative methods employed in the evaluation of drug-polymer miscibility. Combination of these techniques can provide deeper insights into the true miscibility of the drug-polymer systems. PMID:26006307

  19. The Intelligence of Dual Simplex Method to Solve Linear Fractional Fuzzy Transportation Problem

    PubMed Central

    Narayanamoorthy, S.; Kalyani, S.

    2015-01-01

    An approach is presented to solve a fuzzy transportation problem with linear fractional fuzzy objective function. In this proposed approach the fractional fuzzy transportation problem is decomposed into two linear fuzzy transportation problems. The optimal solution of the two linear fuzzy transportations is solved by dual simplex method and the optimal solution of the fractional fuzzy transportation problem is obtained. The proposed method is explained in detail with an example. PMID:25810713

  20. An Efficient Boundary Integral Method for the Mullins Sekerka Problem

    NASA Astrophysics Data System (ADS)

    Zhu, Jingyi; Chen, Xinfu; Hou, Thomas Y.

    1996-09-01

    We use a boundary integral technique to study the two space dimensional Mullins-Sekerka free boundary problem which originates from a study of solidification and liquidation of materials of negligible specific heat. This is an area preserving and curve shortening motion. Evolution equations for the free boundaries are derived in terms of the tangent angle and total arclength, which makes a small scale decomposition possible and the Fourier transform a powerful tool in numerical calculations. With this formulation, implicit schemes can be implemented to avoid the difficult numerical stiffness associated with explicit schemes. We can compute solutions up to the time when there is a topological change, i.e., when particles touch or break up. Our numerical results for systems of a single particle or multi-particles provide some valuable information in the particle dynamics, such as the circularization of each individual particle, and the mass transfer between different particles during particle interactions.

  1. [Simulation as a method for solving medical technical problems].

    PubMed

    Wittmann, J; Obermayer, A

    1995-05-01

    The present paper first presents a comprehensive overview of the methodological aspects of simulation. It lists the various approaches to the modelling of real-world systems and emphasizes the respective constraints on the interpretation of model data. For this purpose, a classification of typical applications of simulation models is given, and is followed by a discussion of three structurally different ways of constructing a model. The correct matching of these modelling concepts to the particular application problem in hand is discussed, with special consideration being given to the drawing of conclusions from, and the interpretation of, the simulation results. To round of the classification, the simulation models are differentiated in accordance with the nature of their implementation. By defining application type, modelling concept and model implementation, an understanding of the validity and appropriate application of any industrial model is derived. PMID:7605886

  2. [Crime under the influence of psychoactive drugs: the problem of the duration of detection].

    PubMed

    Kintz, P; Villain, M; Cirimele, V; Goullé, J P; Ludes, B

    2002-01-01

    On a regular basis, the media presents the potential risks of the use of psycho-active compounds, including misused pharmaceuticals (flunitrazepam, GHB) or drugs of abuse (cannabis, LSD, ecstasy). Ethanol is also frequently encountered. These drugs can be used for recreational purposes by addicts or can be observed after sexual assaults (drugs spiked in food). Forensic toxicology can be involved in several situations to document impairment, such as: crime under influence, date rape, driving under influence, psychiatric disorders, determination of the cause of death... In some particular situations, it can be very cautious to investigate exposure to psycho-active drugs, due to late sampling of biological specimens. To enhance the window of detection of 3 specific drugs, the authors propose the following: 1. Use of an ultra-sensitive technique, such as GC/MS/MS/NCI for 7-aminoflunitrazepam; 2. Use of a cumulative specimen, such as sweat for GHB and 3. Use of a metabolite with a long half-life, such as ethyl glucuronide for ethanol. PMID:11974439

  3. Haar wavelet operational matrix method for solving constrained nonlinear quadratic optimal control problem

    NASA Astrophysics Data System (ADS)

    Swaidan, Waleeda; Hussin, Amran

    2015-10-01

    Most direct methods solve finite time horizon optimal control problems with nonlinear programming solver. In this paper, we propose a numerical method for solving nonlinear optimal control problem with state and control inequality constraints. This method used quasilinearization technique and Haar wavelet operational matrix to convert the nonlinear optimal control problem into a quadratic programming problem. The linear inequality constraints for trajectories variables are converted to quadratic programming constraint by using Haar wavelet collocation method. The proposed method has been applied to solve Optimal Control of Multi-Item Inventory Model. The accuracy of the states, controls and cost can be improved by increasing the Haar wavelet resolution.

  4. Spectral methods and their implementation to solution of aerodynamic and fluid mechanic problems

    NASA Technical Reports Server (NTRS)

    Streett, C. L.

    1987-01-01

    Fundamental concepts underlying spectral collocation methods, especially pertaining to their use in the solution of partial differential equations, are outlined. Theoretical accuracy results are reviewed and compared with results from test problems. A number of practical aspects of the construction and use of spectral methods are detailed, along with several solution schemes which have found utility in applications of spectral methods to practical problems. Results from a few of the successful applications of spectral methods to problems of aerodynamic and fluid mechanic interest are then outlined, followed by a discussion of the problem areas in spectral methods and the current research under way to overcome these difficulties.

  5. A computational method for drug repositioning using publicly available gene expression data

    PubMed Central

    2015-01-01

    Motivation The identification of new therapeutic uses of existing drugs, or drug repositioning, offers the possibility of faster drug development, reduced risk, lesser cost and shorter paths to approval. The advent of high throughput microarray technology has enabled comprehensive monitoring of transcriptional response associated with various disease states and drug treatments. This data can be used to characterize disease and drug effects and thereby give a measure of the association between a given drug and a disease. Several computational methods have been proposed in the literature that make use of publicly available transcriptional data to reposition drugs against diseases. Method In this work, we carry out a data mining process using publicly available gene expression data sets associated with a few diseases and drugs, to identify the existing drugs that can be used to treat genes causing lung cancer and breast cancer. Results Three strong candidates for repurposing have been identified- Letrozole and GDC-0941 against lung cancer, and Ribavirin against breast cancer. Letrozole and GDC-0941 are drugs currently used in breast cancer treatment and Ribavirin is used in the treatment of Hepatitis C. PMID:26679199

  6. A multilevel multiscale mimetic method for an anisotropic infiltration problem

    SciTech Connect

    Lipnikov, Konstantin; Moulton, David; Svyatskiy, Daniil

    2009-01-01

    Modeling of multiphase flow and transport in highly heterogeneous porous media must capture a broad range of coupled spatial and temporal scales. Recently, a hierarchical approach dubbed the Multilevel Multiscale Mimetic (M3) method, was developed to simulate two-phase flow in porous media. The M{sup 3} method is locally mass conserving at all levels in its hierarchy, it supports unstructured polygonal grids and full tensor permeabilities, and it can achieve large coarsening factors. In this work we consider infiltration of water into a two-dimensional layered medium. The grid is aligned with the layers but not the coordinate axes. We demonstrate that with an efficient temporal updating strategy for the coarsening parameters, fine-scale accuracy of prominent features in the flow is maintained by the M{sup 3} method.

  7. Iterative methods for stationary convection-dominated transport problems

    SciTech Connect

    Bova, S.W.; Carey, G.F.

    1994-12-31

    It is well known that many iterative methods fail when applied to nonlinear systems of convection-dominated transport equations. Most successful methods for obtaining steady-state solutions to such systems rely on time-stepping through an artificial transient, combined with careful construction of artificial dissipation operators. These operators provide control over spurious oscillations which pollute the steady state solutions, and, in the nonlinear case, may become amplified and lead to instability. In the present study, we investigate Taylor Galerkin and SUPG-type methods and compare results for steady-state solutions to the Euler equations of gas dynamics. In particular, we consider the efficiency of different iterative strategies and present results for representative two-dimensional calculations.

  8. The workshop on iterative methods for large scale nonlinear problems

    SciTech Connect

    Walker, H.F.; Pernice, M.

    1995-12-01

    The aim of the workshop was to bring together researchers working on large scale applications with numerical specialists of various kinds. Applications that were addressed included reactive flows (combustion and other chemically reacting flows, tokamak modeling), porous media flows, cardiac modeling, chemical vapor deposition, image restoration, macromolecular modeling, and population dynamics. Numerical areas included Newton iterative (truncated Newton) methods, Krylov subspace methods, domain decomposition and other preconditioning methods, large scale optimization and optimal control, and parallel implementations and software. This report offers a brief summary of workshop activities and information about the participants. Interested readers are encouraged to look into an online proceedings available at http://www.usi.utah.edu/logan.proceedings. In this, the material offered here is augmented with hypertext abstracts that include links to locations such as speakers` home pages, PostScript copies of talks and papers, cross-references to related talks, and other information about topics addresses at the workshop.

  9. Understanding the Global Problem of Drug Addiction is a Challenge for IDARS Scientists

    PubMed Central

    Ali, S.F; Onaivi, E.S; Dodd, P.R; Cadet, J.L; Schenk, S; Kuhar, M.J; Koob, G.F

    2011-01-01

    IDARS is an acronym for the International Drug Abuse Research Society. Apart from our scientific and educational purposes, we communicate information to the general and scientific community about substance abuse and addiction science and treatment potential. Members of IDARS are research scientists and clinicians from around the world, with scheduled meetings across the globe. IDARS is developing a vibrant and exciting international mechanism not only for scientific interactions in the domain of addiction between countries but also ultimately as a resource for informing public policy across nations. Nonetheless, a lot more research needs to be done to better understand the neurobiological basis of drug addiction – A challenge for IDARS scientists. PMID:21886551

  10. Application of the Spectral Element Method to Interior Noise Problems

    NASA Technical Reports Server (NTRS)

    Doyle, James F.

    1998-01-01

    The primary effort of this research project was focused the development of analytical methods for the accurate prediction of structural acoustic noise and response. Of particular interest was the development of curved frame and shell spectral elements for the efficient computational of structural response and of schemes to match this to the surrounding fluid.

  11. Reconstructing Program Theories: Methods Available and Problems To Be Solved.

    ERIC Educational Resources Information Center

    Leeuw, Frans L.

    2003-01-01

    Discusses methods for reconstructing theories underlying programs and policies, focusing on three approaches: (1) an empirical approach that focuses on interviews, documents, and argumentational analysis; (2) an approach based on strategic assessment, group dynamics, and dialogue; and (3) an approach based on cognitive and organizational…

  12. Risk Assessment of Drug Management Process in Women Surgery Department of Qaem Educational Hospital (QEH) Using HFMEA Method (2013)

    PubMed Central

    khani-Jazani, Reza; Molavi-Taleghani, Yasamin; Seyedin, Hesam; Vafaee-Najar, Ali; Ebrahimipour, Hossein; Pourtaleb, Arefeh

    2015-01-01

    Evaluation and improvement of drug management process are essential for patient safety. The present study was performed whit the aim of assessing risk of drug management process in Women Surgery Department of QEH using HFMEA method in 2013. A mixed method was used to analyze failure modes and their effects with HFMEA. To classify failure modes; nursing errors in clinical management model, for classifying factors affecting error; approved model by the UK National Health System, and for determining solutions for improvement; Theory of Inventive Problem Solving, were used. 48 failure modes were identified for 14 sub-process of five steps drug management process. The frequency of failure modes were as follow :35.3% in supplying step, 20.75% in prescription step, 10.4% in preparing step, 22.9% in distribution step and 10.35% in follow up and monitoring step. Seventeen failure modes (35.14%) were considered as non-acceptable risk (hazard score≥ 8) and were transferred to decision tree. Among 51 Influencing factors, the most common reasons for error were related to environmental factors (21.5%), and the less common reasons for error were related to patient factors (4.3%). HFMEA is a useful tool to evaluating, prioritization and analyzing failure modes in drug management process. Revision drug management process based focus-PDCA, assessing adverse drug reactions (ADR), USE patient identification bracelet, holding periodical pharmaceutical conferences to improve personnel knowledge, patient contribution in drug therapy; are performance solutions which were placed in work order. PMID:25901157

  13. Risk Assessment of Drug Management Process in Women Surgery Department of Qaem Educational Hospital (QEH) Using HFMEA Method (2013).

    PubMed

    Khani-Jazani, Reza; Molavi-Taleghani, Yasamin; Seyedin, Hesam; Vafaee-Najar, Ali; Ebrahimipour, Hossein; Pourtaleb, Arefeh

    2015-01-01

    Evaluation and improvement of drug management process are essential for patient safety. The present study was performed whit the aim of assessing risk of drug management process in Women Surgery Department of QEH using HFMEA method in 2013. A mixed method was used to analyze failure modes and their effects with HFMEA. To classify failure modes; nursing errors in clinical management model, for classifying factors affecting error; approved model by the UK National Health System, and for determining solutions for improvement; Theory of Inventive Problem Solving, were used. 48 failure modes were identified for 14 sub-process of five steps drug management process. The frequency of failure modes were as follow :35.3% in supplying step, 20.75% in prescription step, 10.4% in preparing step, 22.9% in distribution step and 10.35% in follow up and monitoring step. Seventeen failure modes (35.14%) were considered as non-acceptable risk (hazard score≥ 8) and were transferred to decision tree. Among 51 Influencing factors, the most common reasons for error were related to environmental factors (21.5%), and the less common reasons for error were related to patient factors (4.3%). HFMEA is a useful tool to evaluating, prioritization and analyzing failure modes in drug management process. Revision drug management process based focus-PDCA, assessing adverse drug reactions (ADR), USE patient identification bracelet, holding periodical pharmaceutical conferences to improve personnel knowledge, patient contribution in drug therapy; are performance solutions which were placed in work order. PMID:25901157

  14. Resolvent approach to the fourier method in a mixed problem for the wave equation

    NASA Astrophysics Data System (ADS)

    Kornev, V. V.; Khromov, A. P.

    2015-04-01

    The method of contour integration as applied to the resolvent of the spectral problem is used to substantiate the Fourier method in a mixed problem for the wave equation with a complex potential and boundary conditions generalizing free-end boundary conditions. Minimum smoothness assumptions are made about the initial data. Krylov's technique of accelerating the convergence of the Fourier method is essentially employed.

  15. The Application of Problem Solving Method on Science Teacher Trainees on the Solution of the Environmental Problems

    ERIC Educational Resources Information Center

    Dogru, Mustafa

    2008-01-01

    Helping students to improve their problems solving skills is the primary target of science teacher trainees. In modern science, for training the students, methods should be used for improving their thinking skills, making connections with events and concepts and scientific operations skills rather than information and definition giving. One of…

  16. The Application of Probabilistic Methods to the Mistuning Problem

    NASA Technical Reports Server (NTRS)

    Griffin, J. H.; Rossi, M. R.; Feiner, D. M.

    2004-01-01

    FMM is a reduced order model for efficiently calculating the forced response of a mistuned bladed disk. FMM ID is a companion program which determines the mistuning in a particular rotor. Together, these methods provide a way to acquire data on the mistuning in a population of bladed disks, and then simulate the forced response of the fleet. This process is tested experimentally, and the simulated results are compared with laboratory measurements of a fleet of test rotors. The method is shown to work quite well. It is found that accuracy of the results depends on two factors: the quality of the statistical model used to characterize mistuning, and how sensitive the system is to errors in the statistical modeling.

  17. Numerical Methods for Forward and Inverse Problems in Discontinuous Media

    SciTech Connect

    Chartier, Timothy P.

    2011-03-08

    The research emphasis under this grant's funding is in the area of algebraic multigrid methods. The research has two main branches: 1) exploring interdisciplinary applications in which algebraic multigrid can make an impact and 2) extending the scope of algebraic multigrid methods with algorithmic improvements that are based in strong analysis.The work in interdisciplinary applications falls primarily in the field of biomedical imaging. Work under this grant demonstrated the effectiveness and robustness of multigrid for solving linear systems that result from highly heterogeneous finite element method models of the human head. The results in this work also give promise to medical advances possible with software that may be developed. Research to extend the scope of algebraic multigrid has been focused in several areas. In collaboration with researchers at the University of Colorado, Lawrence Livermore National Laboratory, and Los Alamos National Laboratory, the PI developed an adaptive multigrid with subcycling via complementary grids. This method has very cheap computing costs per iterate and is showing promise as a preconditioner for conjugate gradient. Recent work with Los Alamos National Laboratory concentrates on developing algorithms that take advantage of the recent advances in adaptive multigrid research. The results of the various efforts in this research could ultimately have direct use and impact to researchers for a wide variety of applications, including, astrophysics, neuroscience, contaminant transport in porous media, bi-domain heart modeling, modeling of tumor growth, and flow in heterogeneous porous media. This work has already led to basic advances in computational mathematics and numerical linear algebra and will continue to do so into the future.

  18. A boundary integral method for an inverse problem in thermal imaging

    NASA Technical Reports Server (NTRS)

    Bryan, Kurt

    1992-01-01

    An inverse problem in thermal imaging involving the recovery of a void in a material from its surface temperature response to external heating is examined. Uniqueness and continuous dependence results for the inverse problem are demonstrated, and a numerical method for its solution is developed. This method is based on an optimization approach, coupled with a boundary integral equation formulation of the forward heat conduction problem. Some convergence results for the method are proved, and several examples are presented using computationally generated data.

  19. Preventing Alcohol and Other Drug Problems in Our Communities: Case Studies and Resources.

    ERIC Educational Resources Information Center

    Community Information Exchange, Washington, DC.

    This publication is part of a project of the Community Information Exchange to identify alcohol and other drug prevention strategies that have been tried and tested by community-based organizations. It contains complete case studies of model projects, the full listing of all technical assistance providers and funders, and abstracts of written…

  20. A Social Role Negotiation Approach to Campus Prevention of Alcohol and Other Drug Problems.

    ERIC Educational Resources Information Center

    Blume, Thomas W.

    This document presents a social role negotiation model to be used in the prevention of alcohol and other drugs on college campuses. Section I focuses on theories and theorizing, explaining the fundamental aspects of a theory formulation project. Section II explores the historical and social context of the social role negotiation model. Patterns of…

  1. Problems Related to Alcohol, Other Drugs, and Violence among Military Students. Prevention Update

    ERIC Educational Resources Information Center

    Higher Education Center for Alcohol, Drug Abuse, and Violence Prevention, 2011

    2011-01-01

    According to a Research Update from the National Institute on Drug Abuse, ongoing operations in Iraq and Afghanistan "continue to strain military personnel, returning veterans, and their families. Some have experienced long and multiple deployments, combat exposure, and physical injuries, as well as post-traumatic stress disorder (PTSD) and…

  2. Protective/Risk Factors for Problem Drug Use: A Longitudinal Analysis.

    ERIC Educational Resources Information Center

    Felix-Ortiz, Maria; Newcomb, Michael D.

    With few exceptions, virtually all research on the etiology of adolescent substance abuse has focused entirely on identifying risk factors while ignoring protective factors that insulate teenagers from drug involvement. This perspective fails to consider that protective forces may operate in both direct and interactive ways. This longitudinal…

  3. Adolescent Drug Abuses-A Problem of Interpersonal Relations and School Organization

    ERIC Educational Resources Information Center

    Dearden, Marlin H.

    1971-01-01

    This paper stresses the importance of listening to students and to each other, and the willingness to explore together those areas of personal concern as they exist in individuals and organizational and administrative operation for an effective drug education program. (Author)

  4. Steps to Success: Helping Women with Alcohol and Drug Problems Move from Welfare to Work.

    ERIC Educational Resources Information Center

    Rubinstein, Gwen

    This report helps state and local decision makers understand the range of services ordinarily needed and provided in alcohol and drug treatment programs serving women and families receiving welfare and how those services support the goals of welfare reform. The model programs profiled here tend to the needs of women on welfare and their families…

  5. Social Marketing Strategies for Campus Prevention of Alcohol and Other Drug Problems.

    ERIC Educational Resources Information Center

    Zimmerman, Robert

    This document sets out one segment of a comprehensive approach intended to assist institutions of higher education in developing and carrying out alcohol abuse and other drug prevention programs. Social marketing is described as a tool of environmental management, that seeks to produce a specified behavior in a target audience. Intended for a…

  6. Faces of Change: Do I Have a Problem with Alcohol or Drugs?

    MedlinePlus

    ... he drank a lot of alcohol. He dropped out of school in his senior year. Now Eric has a ... his life, Don was able to finish high school and find a good ... touched drugs in 10 years. He likes to work out at the gym, and he has made a ...

  7. State Resources and Services for Alcohol and Drug Abuse Problems. Fiscal Year 1985.

    ERIC Educational Resources Information Center

    Butynski, William; And Others

    This report presents and analyzes the results of the State Alcohol and Drug Abuse Profile data for the states' 1985 fiscal year (FY). Included is information from the 50 states, the District of Columbia, Guam, Puerto Rico, and the Virgin Islands. Highlights, an executive summary, an introduction, and a section on the study purpose and methodology…

  8. A novel preparation method for drug nanocrystals and characterization by ultrasonic spray-assisted electrostatic adsorption

    PubMed Central

    Gao, Bing; Wang, Jun; Wang, Dunju; Zhu, Ziqiang; Qiao, Zhiqiang; Yang, Guangcheng; Nie, Fude

    2013-01-01

    Purpose The purpose of this study was to develop a novel and continuous method for preparing a nanosized particle of drug crystals and to characterize its properties. Materials and methods A new apparatus was introduced to crystallize nanosized drug crystals of amitriptyline hydrochloride as a model drug. The samples were prepared in the pure state by ultrasonic spray, and elaborated deposition was completed via electrostatic adsorption. Scanning electron microscopy, X-ray powder diffraction, and atomic force microscopy were used to characterize the size of the particles; this was subsequently followed by differential scanning calorimetry. Results and discussion Nanoparticles of drug crystals were successfully prepared. The size of the drug crystals ranged from 20 nm to 400 nm; the particle size of amitriptyline hydrochloride was approximately 71 nm. The particles were spherical and rectangular in shape. Moreover, the melting point of the nanoparticles decreased from 198.2°C to 196.3°C when compared to raw particle crystals. Furthermore, the agglomeration effect was also attenuated as a result of electrostatic repulsion among each particle when absorbed, and depositing on the inner wall of the gathering unit occurred under the electrostatic effect. Conclusion Ultrasonic spray-assisted electrostatic adsorption is a very effective and continuous method to produce drug nanocrystals. This method can be applied to poorly water-soluble drugs, and it can also be a very effective alternative for industrial production. Once the working parameters are given, drug nanocrystals will be produced continuously. PMID:24143097

  9. Methods for quantitative determination of drug localized in the skin.

    PubMed

    Touitou, E; Meidan, V M; Horwitz, E

    1998-12-01

    The quantification of drugs within the skin is essential for topical and transdermal delivery research. Over the last two decades, horizontal sectioning, consisting of both tape stripping and parallel slicing through the deeper tissues has constituted the traditional investigative technique. In recent years, this methodology has been augmented by such procedures as heat separation, qualitative autoradiography, isolation of the pilosebaceous units and the use of induced follicle-free skin. The development of skin quantitative autoradiography represents an entirely novel approach which permits quantification and visualization of the penetrant throughout a vertical cross-section of skin. Noninvasive strategies involve the application of optical measuring systems such as attenuated total reflectance Fourier transform infrared, fluorescence, remittance or photothermal spectroscopies. PMID:9801425

  10. Tentative method for the qualitative detection and quantitative assessment of air contamination by drugs.

    PubMed

    Buogo, A; Eboli, V

    1972-06-01

    A method for detecting and measuring air contamination by drugs is described which uses an electrostatic bacterial air sampler, sprayers for micronizing drugs, and Mueller-Hinton medium seeded with a highly susceptible strain of Sarcina lutea. Three antibiotics (penicillin, tetracycline, aminosidine) and a sulfonamide (sulfapyrazine) were identified by pretreating portions of medium, showing no bacterial growth, with penicillinase or p-aminobenzoic acid solution and subsequently determining how both drug(-) susceptible and drug-resistant strains of Staphylococcus aureus were affected by this pretreatment. Quantitative determinations were also attempted by measuring the size of the inhibition zones. PMID:4483536

  11. Tentative Method for the Qualitative Detection and Quantitative Assessment of Air Contamination by Drugs

    PubMed Central

    Buogo, A.; Eboli, V.

    1972-01-01

    A method for detecting and measuring air contamination by drugs is described which uses an electrostatic bacterial air sampler, sprayers for micronizing drugs, and Mueller-Hinton medium seeded with a highly susceptible strain of Sarcina lutea. Three antibiotics (penicillin, tetracycline, aminosidine) and a sulfonamide (sulfapyrazine) were identified by pretreating portions of medium, showing no bacterial growth, with penicillinase or p-aminobenzoic acid solution and subsequently determining how both drug- susceptible and drug-resistant strains of Staphylococcus aureus were affected by this pretreatment. Quantitative determinations were also attempted by measuring the size of the inhibition zones. Images PMID:4483536

  12. A hybrid method for prediction and repositioning of drug Anatomical Therapeutic Chemical classes.

    PubMed

    Chen, Lei; Lu, Jing; Zhang, Ning; Huang, Tao; Cai, Yu-Dong

    2014-04-01

    In the Anatomical Therapeutic Chemical (ATC) classification system, therapeutic drugs are divided into 14 main classes according to the organ or system on which they act and their chemical, pharmacological and therapeutic properties. This system, recommended by the World Health Organization (WHO), provides a global standard for classifying medical substances and serves as a tool for international drug utilization research to improve quality of drug use. In view of this, it is necessary to develop effective computational prediction methods to identify the ATC-class of a given drug, which thereby could facilitate further analysis of this system. In this study, we initiated an attempt to develop a prediction method and to gain insights from it by utilizing ontology information of drug compounds. Since only about one-fourth of drugs in the ATC classification system have ontology information, a hybrid prediction method combining the ontology information, chemical interaction information and chemical structure information of drug compounds was proposed for the prediction of drug ATC-classes. As a result, by using the Jackknife test, the 1st prediction accuracies for identifying the 14 main ATC-classes in the training dataset, the internal validation dataset and the external validation dataset were 75.90%, 75.70% and 66.36%, respectively. Analysis of some samples with false-positive predictions in the internal and external validation datasets indicated that some of them may even have a relationship with the false-positive predicted ATC-class, suggesting novel uses of these drugs. It was conceivable that the proposed method could be used as an efficient tool to identify ATC-classes of novel drugs or to discover novel uses of known drugs. PMID:24492783

  13. Coupling finite and boundary element methods for 2-D elasticity problems

    NASA Technical Reports Server (NTRS)

    Krishnamurthy, T.; Raju, I. S.; Sistla, R.

    1993-01-01

    A finite element-boundary element (FE-BE) coupling method for two-dimensional elasticity problems is developed based on a weighted residual variational method in which a portion of the domain of interest is modeled by FEs and the remainder of the region by BEs. The performance of the FE-BE coupling method is demonstrated via applications to a simple 'patch test' problem and three-crack problems. The method passed the patch tests for various modeling configurations and yielded accurate strain energy release rates for the crack problems studied.

  14. The Effect of Parenting Stress on Child Behavior Problems in High-Risk Children with Prenatal Drug Exposure

    ERIC Educational Resources Information Center

    Bagner, Daniel M.; Sheinkopf, Stephen J.; Miller-Loncar, Cynthia; LaGasse, Linda L.; Lester, Barry M.; Liu, Jing; Bauer, Charles R.; Shankaran, Seetha; Bada, Henrietta; Das, Abhik

    2009-01-01

    Objective: To examine the relationship between early parenting stress and later child behavior in a high-risk sample and measure the effect of drug exposure on the relationship between parenting stress and child behavior. Methods: A subset of child-caregiver dyads (n = 607) were selected from the Maternal Lifestyle Study (MLS), which is a large…

  15. Optimized fourth-order Runge-Kutta method for solving oscillatory problems

    NASA Astrophysics Data System (ADS)

    Hussain, Kasim; Ismail, Fudziah; Senu, Norazak; Rabiei, Faranak

    2016-06-01

    In this article, we develop a Runge-Kutta method with invalidation of phase lag, phase lag's derivatives and amplification error to solve second-order initial value problem (IVP) with oscillating solutions. The new method depends on the explicit Runge-Kutta method of algebraic order four. Numerical tests from its implementation to well-known oscillatory problems illustrate the robustness and competence of the new method as compared to the well-known Runge-Kutta methods in the scientific literature.

  16. Study of hybrid methods for approximating the Edgeworth-Pareto hull in nonlinear multicriteria optimization problems

    NASA Astrophysics Data System (ADS)

    Berezkin, V. E.; Lotov, A. V.; Lotova, E. A.

    2014-06-01

    Methods for approximating the Edgeworth-Pareto hull (EPH) of the set of feasible criteria vectors in nonlinear multicriteria optimization problems are examined. The relative efficiency of two EPH approximation methods based on classical methods of searching for local extrema of convolutions of criteria is experimentally studied for a large-scale applied problem (with several hundred variables). A hybrid EPH approximation method combining classical and genetic approximation methods is considered.

  17. A comparison of several methods of solving nonlinear regression groundwater flow problems.

    USGS Publications Warehouse

    Cooley, R.L.

    1985-01-01

    Computational efficiency and computer memory requirements for four methods of minimizing functions were compared for four test nonlinear-regression steady state groundwater flow problems. The fastest methods were the Marquardt and quasi-linearization methods, which required almost identical computer times and numbers of iterations; the next fastest was the quasi-Newton method, and last was the Fletcher-Reeves method, which did not converge in 100 iterations for two of the problems.-from Author

  18. Extragradient methods for searching for equilibrium points in the parametric problem of equilibrium programming

    NASA Astrophysics Data System (ADS)

    Artem'eva, L. A.

    2014-12-01

    The parametric problem of equilibrium programming is examined. The mathematical programming problem, the search for a saddle-point, the multicriteria search for a Pareto point, etc. are particular cases of this parametric problem. The primal and dual variants of the extragradient method are proposed as a tool for searching for equilibrium points. The convergence of both variants is analyzed.

  19. Links between alcohol and other drug problems and maltreatment among adolescent girls: Perceived discrimination, ethnic identity, and ethnic orientation as moderators

    PubMed Central

    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 of 168 Black and Hispanic adolescent girls who participated in a school-based substance use intervention. Results The results revealed that maltreatment was linked to AOD problems, but only through its relation with posttraumatic stress symptoms; maltreatment was positively related to posttraumatic stress symptoms, which were positively related to AOD problems. Both perceived discrimination and ethnic orientation were significant moderators. Specifically, greater perceived discrimination was associated with an increased effect of maltreatment on posttraumatic stress symptoms. Ethnic orientation demonstrated protective properties in the relation between maltreatment and AOD problem severity, such that the effect of maltreatment on AOD problem severity was less for girls with average to high ethnic orientation compared to girls with low ethnic orientation. Conclusions The findings of this study underscore the importance of developing interventions for Black and Hispanic girls that target maltreatment and AOD use concurrently and address ethnicity-specific factors. PMID:22608406

  20. Human placental perfusion method in the assessment of transplacental passage of antiepileptic drugs

    SciTech Connect

    Myllynen, Paeivi . E-mail: paivi.k.myllynen@oulu.fi; Pienimaeki, Paeivi; Vaehaekangas, Kirsi

    2005-09-01

    Epilepsy is one of the most common neurological diseases, affecting about 0.5 to 1% of pregnant women. It is commonly accepted that older antiepileptic drugs bear teratogenic potential. So far, no agreement has been reached about the safest antiepileptic drug during pregnancy. It is known that nearly all drugs cross the placenta at least to some extent. Nowadays, there is very little information available of the pharmacokinetics of drugs in the feto-placental unit. Detailed information about drug transport across the placenta would be valuable for the development of safe and effective treatments. For reasons of safety, human studies on placental transfer are restricted to a limited number of drugs. Interspecies differences limit the extrapolation of animal data to humans. Several in vitro methods for the study of placental transfer have been developed over the past decades. The placental perfusion method is the only experimental method that has been used to study human placental transfer of substances in organized placental tissue. The aim of this article is to review human placental perfusion data on antiepileptic drugs. According to perfusion data, it seems that most of the antiepileptic drugs are transferred across the placenta meaning significant fetal exposure.

  1. Reversal of drug-induced anticoagulation: old solutions and new problems.

    PubMed

    Dzik, Walter Sunny

    2012-05-01

    Anticoagulant drugs are taken by millions of patients throughout the world. Warfarin has been the most widely prescribed anticoagulant for decades. In recent years, new oral anticoagulants have been approved for use, are being positioned as alternatives to warfarin, and represent an enormous market opportunity for pharmaceutical companies. Requests for urgent reversal of anticoagulants are not uncommon especially in the setting of critical bleeding. This review summarizes information on reversal of warfarin by vitamin K, plasma, prothrombin complex concentrates, and recombinant VIIa. In addition, we emphasize the lack of current evidence supporting reversibility of the new oral direct thrombin inhibitors and Factor Xa inhibitors. This review is presented to assist transfusion medicine specialists, hematologists, and other clinicians who prescribe blood components for reversal of drug-induced anticoagulation. PMID:22578371

  2. Design of Drug Delivery Methods for the Brain and Central Nervous System

    NASA Astrophysics Data System (ADS)

    Lueshen, Eric

    -enhanced drug delivery (CED) is a technique used to bypass the BBB via direct intracranial injection using a catheter driven by a positive pressure gradient from an infusion pump. Although CED boasts the advantage of achieving larger drug distribution volumes compared to diffusion driven methods, difficulty in predicting drug spread and preventing backflow along the catheter shaft commonly occur. In this dissertation, a method for predicting drug distributions in the brain using diffusion tensor imaging (DTI) data is employed to show how small variations in catheter placement can lead to drastically different volumes of drug distribution in vivo. The impact that microfluid flow has on deformable brain phantom gel is studied in order to elucidate the causes of backflow, and the results are used to develop backflow-free catheters with safe volumetric flow rates up to 10 ?l/min. Through implementation of our backflow-free catheter designs, physicians will be able to target specific regions of the brain with improved accuracy, increased drug concentration, and larger drug distribution geometries. Intrathecal (IT) drug delivery involves direct drug infusion into the spinal canal and has become standard practice for treating many CNS diseases. Although IT drug delivery boasts the advantage of reduced systemic toxicity compared to oral and intravenous techniques, current IT delivery protocols lack a means of sufficient drug targeting at specific locations of interest within the CNS. In this dissertation, the method of intrathecal magnetic drug targeting (IT-MDT) is developed to overcome the limited targeting capabilities of standard IT drug delivery protocols. The basic idea behind IT-MDT is to guide intrathecally-injected, drug-functionalized magnetic nanoparticles (MNPs) using an external magnetic field to diseased regions within the spinal canal. Cerebrospinal fluid (CSF) transport phenomena are studied, and in vitro human spine surrogates are built. Experiments are run on the in

  3. [The use of benzodiazepines and Z-drugs for patients with sleeping problems - A survey among hospital doctors and nurses].

    PubMed

    Weiß, V; Heinemann, S; Himmel, W; Nau, R; Hummers-Pradier, E

    2016-07-01

    Aim | Benzodiazepines and Z-drugs are frequently prescribed sleep medications in spite of their poor risk-benefit ratio when used over a longer period of time. The aim of the study was to find out how the medical and nursing staff in a general hospital estimated the frequency of use for these drugs, and the risk-benefit ratio for elderly patients as well as the factors which positively influence the perceived use of these drugs. Methods | All members of the medical and nursing staff of a hospital received a questionnaire about their use of, and attitudes towards, benzodiazepines and Z-drugs. Absolute and relative frequencies were calculated to estimate the perceived frequency of use and the risk-benefit ratio. Multiple logistic regressions were used to analyze which factors are associated with a perceived high use of benzodiazepines or Z-drugs for insomnia. Results | More nurses than hospital doctors believed that they dispensed benzodiazepines often or always (57 % vs. 29 %) to patients with insomnia; this was also the case for Z-drugs (66 % vs. 29 %). Nearly half of the hospital doctors and 29 % of the nurses perceived more harms than benefits for benzodiazepines in the elderly. The following factors were associated with a high perceived usage of Z-drugs: working as a nurse (OR: 13,95; 95%-CI: 3,87-50,28), working in a non-surgical department (5,41; 2,00-14,61), having < 5 years of professional experience (4,90; 1,43-16,81) and feeling that the benefits of Z-drugs outweigh the risks for elderly patients (5,07; 1,48-17,35). For benzodiazepines, only the perceived positive risk-benefit ratio had an influence on the perceived use (3,35; 1,28-8.79). Conclusion | The medical and nursing staff perceived the frequency of prescription of benzodiazepines and Z-drugs and the risk-benefit ratio in different ways. Other aspects, such as working in a non-surgical department or having a smaller amount of working experience may also influence the decision to use Z-drugs. PMID

  4. The Predictive Power of Family History Measures of Alcohol and Drug Problems and Internalizing Disorders In A College Population

    PubMed Central

    Kendler, Kenneth S; Edwards, Alexis; Myers, John; Cho, Seung Bin; Adkins, Amy; Dick, Danielle

    2015-01-01

    A family history (FH) of psychiatric and substance use problems is a potent risk factor for common internalizing and externalizing disorders. In a large web-based assessment of mental health in college students, we developed a brief set of screening questions for a FH of alcohol problems (AP), drug problems (DP) and depression-anxiety in four classes of relatives (father, mother, aunts/uncles/grandparents, and siblings) as reported by the student. Positive reports of a history of AP, DP, and depression-anxiety were substantially correlated within relatives. These FH measures predicted in the student, in an expected pattern, dimensions of personality and impulsivity, alcohol consumption and problems, smoking and nicotine dependence, use of illicit drugs, and symptoms of depression and anxiety. Using the mean score from the four classes of relatives was more predictive than using a familial/sporadic dichotomy. Interactions were seen between the FH of AP, DP, and depression-anxiety and peer deviance in predicting symptoms of alcohol and tobacco dependence. As the students aged, the FH of AP became a stronger predictor of alcohol problems. While we cannot directly assess the validity of these FH reports, the pattern of findings suggest that our brief screening items were able to assess, with some accuracy, the FH of substance misuse and internalizing psychiatric disorders in relatives. If correct, these measures can play an important role in the creation of developmental etiologic models for substance and internalizing psychiatric disorders which constitute one of the central goals of the overall project. PMID:25946510

  5. The predictive power of family history measures of alcohol and drug problems and internalizing disorders in a college population.

    PubMed

    Kendler, Kenneth S; Edwards, Alexis; Myers, John; Cho, Seung Bin; Adkins, Amy; Dick, Danielle

    2015-07-01

    A family history (FH) of psychiatric and substance use problems is a potent risk factor for common internalizing and externalizing disorders. In a large web-based assessment of mental health in college students, we developed a brief set of screening questions for a FH of alcohol problems (AP), drug problems (DP) and depression-anxiety in four classes of relatives (father, mother, aunts/uncles/grandparents, and siblings) as reported by the student. Positive reports of a history of AP, DP, and depression-anxiety were substantially correlated within relatives. These FH measures predicted in the student, in an expected pattern, dimensions of personality and impulsivity, alcohol consumption and problems, smoking and nicotine dependence, use of illicit drugs, and symptoms of depression and anxiety. Using the mean score from the four classes of relatives was more predictive than using a familial/sporadic dichotomy. Interactions were seen between the FH of AP, DP, and depression-anxiety and peer deviance in predicting symptoms of alcohol and tobacco dependence. As the students aged, the FH of AP became a stronger predictor of alcohol problems. While we cannot directly assess the validity of these FH reports, the pattern of findings suggest that our brief screening items were able to assess, with some accuracy, the FH of substance misuse and internalizing psychiatric disorders in relatives. If correct, these measures can play an important role in the creation of developmental etiologic models for substance and internalizing psychiatric disorders which constitute one of the central goals of the overall project. PMID:25946510

  6. Direct SQP-methods for solving optimal control problems with delays

    SciTech Connect

    Goellmann, L.; Bueskens, C.; Maurer, H.

    1994-12-31

    The maximum principle for optimal control problems with delays leads to a boundary value problem (BVP) which is retarded in the state and advanced in the costate function. Based on shooting techniques, solution methods for this type of BVP have been proposed. In recent years, direct optimization methods have been favored for solving control problems without delays. Direct methods approximate the control and the state over a fixed mesh and solve the resulting NLP-problem with SQP-methods. These methods dispense with the costate function and have shown to be robust and efficient. In this paper, we propose a direct SQP-method for retarded control problems. In contrast to conventional direct methods, only the control variable is approximated by e.g. spline-functions. The state is computed via a high order Runge-Kutta type algorithm and does not enter explicitly the NLP-problem through an equation. This approach reduces the number of optimization variables considerably and is implementable even on a PC. Our method is illustrated by the numerical solution of retarded control problems with constraints. In particular, we consider the control of a continuous stirred tank reactor which has been solved by dynamic programming. This example illustrates the robustness and efficiency of the proposed method. Open questions concerning sufficient conditions and convergence of discretized NLP-problems are discussed.

  7. Searching for Truth: Internet Search Patterns as a Method of Investigating Online Responses to a Russian Illicit Drug Policy Debate

    PubMed Central

    Gillespie, James A; Quinn, Casey

    2012-01-01

    Background This is a methodological study investigating the online responses to a national debate over an important health and social problem in Russia. Russia is the largest Internet market in Europe, exceeding Germany in the absolute number of users. However, Russia is unusual in that the main search provider is not Google, but Yandex. Objective This study had two main objectives. First, to validate Yandex search patterns against those provided by Google, and second, to test this method's adequacy for investigating online interest in a 2010 national debate over Russian illicit drug policy. We hoped to learn what search patterns and specific search terms could reveal about the relative importance and geographic distribution of interest in this debate. Methods A national drug debate, centering on the anti-drug campaigner Egor Bychkov, was one of the main Russian domestic news events of 2010. Public interest in this episode was accompanied by increased Internet search. First, we measured the search patterns for 13 search terms related to the Bychkov episode and concurrent domestic events by extracting data from Google Insights for Search (GIFS) and Yandex WordStat (YaW). We conducted Spearman Rank Correlation of GIFS and YaW search data series. Second, we coded all 420 primary posts from Bychkov's personal blog between March 2010 and March 2012 to identify the main themes. Third, we compared GIFS and Yandex policies concerning the public release of search volume data. Finally, we established the relationship between salient drug issues and the Bychkov episode. Results We found a consistent pattern of strong to moderate positive correlations between Google and Yandex for the terms "Egor Bychkov" (r s = 0.88, P < .001), “Bychkov” (r s = .78, P < .001) and “Khimki”(r s = 0.92, P < .001). Peak search volumes for the Bychkov episode were comparable to other prominent domestic political events during 2010. Monthly search counts were 146,689 for “Bychkov” and

  8. An overview of the optical and electrochemical methods for detection of DNA - drug interactions.

    PubMed

    Aleksić, Mara M; Kapetanović, Vera

    2014-01-01

    A large number of inorganic and organic compounds is able to bind to DNA and form complexes. Among them, drugs are very important, especially chemotherapeutics. This paper presents the overview of DNA structural characteristics and types of interactions (covalent and non-covalent) between DNA molecule and drugs. Covalent binding of the drug is irreversible and leads to complete inhibition of DNA function, what conclusively, causes the cell death. On the other hand, non-covalent binding is reversible and based on the principle of molecular recognition. Special attention is given to elucidation of the specific sites in DNA molecule for drug binding. According to their structural characteristics, drugs that react non-covalently with DNA are mainly intercalators, but also minor and major groove binders. When the complex between drug and DNA is formed, both the drug molecule, as well as DNA, experienced some modifications. This paper presents the overview of the methods used for the study of the interactions between DNA and drugs with the aim of detection and explanation of the resulting changes. For this purpose many spectroscopic methods like UV/VIS, fluorescence, infrared and NMR, polarized light spectroscopies like circular and linear dichroism, and fluorescence anisotropy or resonance is used. The development of the electrochemical DNA biosensors has opened a wide perspective using particularly sensitive and selective electrochemical methods for the detection of specific DNA interactions. The presented results summarize literature data obtained by the mentioned methods. The results are used to confirm the DNA damage, to determine drug binding sites and sequence preference, as well as conformational changes due to drug-DNA interaction. PMID:25286211

  9. Solving nonlinear heat conduction problems with multigrid preconditioned Newton-Krylov methods

    SciTech Connect

    Rider, W.J.; Knoll, D.A.

    1997-09-01

    Our objective is to investigate the utility of employing multigrid preconditioned Newton-Krylov methods for solving initial value problems. Multigrid based method promise better performance from the linear scaling associated with them. Our model problem is nonlinear heat conduction which can model idealized Marshak waves. Here we will investigate the efficiency of using a linear multigrid method to precondition a Krylov subspace method. In effect we will show that a fixed point nonlinear iterative method provides an effective preconditioner for the nonlinear problem.

  10. The double exponential sinc collocation method for singular Sturm-Liouville problems

    NASA Astrophysics Data System (ADS)

    Gaudreau, P.; Slevinsky, R.; Safouhi, H.

    2016-04-01

    Sturm-Liouville problems are abundant in the numerical treatment of scientific and engineering problems. In the present contribution, we present an efficient and highly accurate method for computing eigenvalues of singular Sturm-Liouville boundary value problems. The proposed method uses the double exponential formula coupled with sinc collocation method. This method produces a symmetric positive-definite generalized eigenvalue system and has exponential convergence rate. Numerical examples are presented and comparisons with single exponential sinc collocation method clearly illustrate the advantage of using the double exponential formula.

  11. [Research on our hospital inventory management status quo of traditional Chinese medicine drugs and treatment method].

    PubMed

    Zhang, Ying-Nan; Xu, Wen

    2014-03-01

    Under the background of the new medical reform, a large variety of traditional Chinese medicine from complicated sources, Chinese traditional medicine of actor of true and false of the quality directly affect the drug safety and clinical efficacy, but also relate to the social and economic benefits of hospital. Along with the development of the modern management of medical institutions and drug circulation circulation system reform in our country, the hospital drug inventory, supply and management work is an important topic for the pharmaceutical trading. However, there is always contradiction, dispensary need to supple pharmacy, in order to satisfy the demands of hospital patients with normal diagnosis and treatment work. However, if the drug inventory is too much, not only increases the drug monitoring problem, at the same time, but also causes storage costs rise. Therefore, completing scientific and reasonable storage and management becomes urgent problems at present. Wherefore, our country administration of traditional Chinese medicine in 2007 promulgated the "Chinese traditional medicine yinpian management norms in hospital", aims to standardize management of Chinese traditional medicine quality and improve the safety of drugs. The author through looking up information and visiting survey, to understand the currently existing problems, and summarizes the literature inland and abroad in recent years Chinese medicine drug inventory management work experience, in view of status quo of Chinese medicine inventory management in China, put forward the solution. To guarantee TCM pharmacy management more standardized, more standard, to adapt to the new reform of Chinese traditional medicine industry, improve the management level of hospital, defend the hospital's reputation and the patient's interests. PMID:24956868

  12. On the Inclusion of Difference Equation Problems and Z Transform Methods in Sophomore Differential Equation Classes

    ERIC Educational Resources Information Center

    Savoye, Philippe

    2009-01-01

    In recent years, I started covering difference equations and z transform methods in my introductory differential equations course. This allowed my students to extend the "classical" methods for (ordinary differential equation) ODE's to discrete time problems arising in many applications.

  13. Methods of noninvasive electrophysiological heart examination basing on solution of inverse problem of electrocardiography

    NASA Astrophysics Data System (ADS)

    Grigoriev, M.; Babich, L.

    2015-09-01

    The article represents the main noninvasive methods of heart electrical activity examination, theoretical bases of solution of electrocardiography inverse problem, application of different methods of heart examination in clinical practice, and generalized achievements in this sphere in global experience.

  14. A comparison of limit setting methods for the on-off problem

    NASA Astrophysics Data System (ADS)

    Rolke, Wolfgang A.

    2016-01-01

    We study the frequentist properties of confidence intervals found with various methods previously proposed for the On-Off problem. We derive explicit formulas for the limits and calculate the true coverage and the expected lengths of these methods.

  15. Numerical Solution of Problems in Calculus of Variations by Homotopy Perturbation Method

    SciTech Connect

    Jafari, M. A.; Aminataei, A.

    2008-09-01

    In this work we use Homotopy Perturbation Method (HPM) to solve differential equations that arise in variational problems. To illustrate the method some examples are provided. The results show the efficiency and accuracy of the HPM. HPM can be considered an alternative method to Adomian decomposition method. Both of these methods can obtain analytic form of the solution in some cases.

  16. A Multifunctional Interface Method for Coupling Finite Element and Finite Difference Methods: Two-Dimensional Scalar-Field Problems

    NASA Technical Reports Server (NTRS)

    Ransom, Jonathan B.

    2002-01-01

    A multifunctional interface method with capabilities for variable-fidelity modeling and multiple method analysis is presented. The methodology provides an effective capability by which domains with diverse idealizations can be modeled independently to exploit the advantages of one approach over another. The multifunctional method is used to couple independently discretized subdomains, and it is used to couple the finite element and the finite difference methods. The method is based on a weighted residual variational method and is presented for two-dimensional scalar-field problems. A verification test problem and a benchmark application are presented, and the computational implications are discussed.

  17. Solution of 3D inverse scattering problems by combined inverse equivalent current and finite element methods

    SciTech Connect

    Kılıç, Emre Eibert, Thomas F.

    2015-05-01

    An approach combining boundary integral and finite element methods is introduced for the solution of three-dimensional inverse electromagnetic medium scattering problems. Based on the equivalence principle, unknown equivalent electric and magnetic surface current densities on a closed surface are utilized to decompose the inverse medium problem into two parts: a linear radiation problem and a nonlinear cavity problem. The first problem is formulated by a boundary integral equation, the computational burden of which is reduced by employing the multilevel fast multipole method (MLFMM). Reconstructed Cauchy data on the surface allows the utilization of the Lorentz reciprocity and the Poynting's theorems. Exploiting these theorems, the noise level and an initial guess are estimated for the cavity problem. Moreover, it is possible to determine whether the material is lossy or not. In the second problem, the estimated surface currents form inhomogeneous boundary conditions of the cavity problem. The cavity problem is formulated by the finite element technique and solved iteratively by the Gauss–Newton method to reconstruct the properties of the object. Regularization for both the first and the second problems is achieved by a Krylov subspace method. The proposed method is tested against both synthetic and experimental data and promising reconstruction results are obtained.

  18. Successive over relaxation method in solving two-point fuzzy boundary value problems

    NASA Astrophysics Data System (ADS)

    Dahalan, A. A.; Muthuvalu, M. S.; Sulaiman, J.

    2013-04-01

    In this study, numerical methods are considered in solving the fuzzy boundary value problem (FBVP). This boundary value problem will then be discretized to derive second order finite difference equation and hence generated fuzzy linear system. The approximation solver towards system of linear equations is described through the implementation of the Gauss-Seidel (GS) and Successive Over Relaxation (SOR) iterative methods. Then several numerical experiments were shown to illustrate the effectiveness of SOR iterative method compared with the GS method.

  19. Reliable Multi Method Assessment of Metacognition Use in Chemistry Problem Solving

    ERIC Educational Resources Information Center

    Cooper, Melanie M.; Sandi-Urena, Santiago; Stevens, Ron

    2008-01-01

    Metacognition is fundamental in achieving understanding of chemistry and developing of problem solving skills. This paper describes an across-method-and-time instrument designed to assess the use of metacognition in chemistry problem solving. This multi method instrument combines a self report, namely the Metacognitive Activities Inventory…

  20. Exploring Methods of Analysing Talk in Problem-Based Learning Tutorials

    ERIC Educational Resources Information Center

    Clouston, Teena J.

    2007-01-01

    This article explores the use of discourse analysis and conversation analysis as an evaluation tool in problem-based learning. The basic principles of the methods are discussed and their application in analysing talk in problem-based learning considered. Findings suggest that these methods could enable an understanding of how effective…

  1. Adaptive finite element methods for two-dimensional problems in computational fracture mechanics

    NASA Technical Reports Server (NTRS)

    Min, J. B.; Bass, J. M.; Spradley, L. W.

    1994-01-01

    Some recent results obtained using solution-adaptive finite element methods in two-dimensional problems in linear elastic fracture mechanics are presented. The focus is on the basic issue of adaptive finite element methods for validating the new methodology by computing demonstration problems and comparing the stress intensity factors to analytical results.

  2. The Model Method: Singapore Children's Tool for Representing and Solving Algebraic Word Problems

    ERIC Educational Resources Information Center

    Ng, Swee Fong; Lee, Kerry

    2009-01-01

    Solving arithmetic and algebraic word problems is a key component of the Singapore elementary mathematics curriculum. One heuristic taught, the model method, involves drawing a diagram to represent key information in the problem. We describe the model method and a three-phase theoretical framework supporting its use. We conducted 2 studies to…

  3. Brief Strategic Family Therapy: Engaging Drug Using/Problem Behavior Adolescents and their Families into Treatment

    PubMed Central

    Szapocznik, José; Zarate, Monica; Duff, Johnathan; Muir, Joan

    2013-01-01

    Despite the efficacy of family-based interventions for improving outcomes for adolescent behavior problems such as substance use, engaging and retaining whole families in treatment is one of the greatest challenges therapists confront. This article illustrates how the Brief Strategic Family Therapy® (BSFT®) model, a family-based, empirically validated intervention designed to treat children and adolescents’ problem behaviors, can be used to increase engagement, improve retention, and bring about positive outcomes for families. Research evidence for efficacy and effectiveness is also presented. PMID:23731415

  4. TranScreen-N: Method for rapid screening of trans-ungual drug delivery enhancers.

    PubMed

    Murthy, S Narasimha; Vaka, Siva Ram Kiran; Sammeta, Srinivasa Murthy; Nair, Anroop B

    2009-11-01

    Topical monotherapy of nail diseases such as onychomycosis and nail psoriasis has been less successful due to poor permeability of the human nail plate to topically administered drugs. Chemical enhancers are utilized to improve the drug delivery across the nail plate. Choosing the most effective chemical enhancers for the given drug and formulation is highly critical in determining the efficacy of topical therapy of nail diseases. Screening the large pool of enhancers using currently followed diffusion cell experiments would be tedious and expensive. The main objective of this study is to develop TranScreen-N, a high throughput method of screening trans-ungual drug permeation enhancers. It is a rapid microwell plate based method which involves two different treatment procedures; the simultaneous exposure treatment and the sequential exposure treatment. In the present study, several chemicals were evaluated by TranScreen-N and by diffusion studies in the Franz diffusion cell (FDC). Good agreement of in vitro drug delivery data with TranScreen-N data provided validity to the screening technique. In TranScreen-N technique, the enhancers can be grouped according to whether they need to be applied before or simultaneously with drugs (or by either procedures) to enhance the drug delivery across the nail plate. TranScreen-N technique can significantly reduce the cost and duration required to screen trans-ungual drug delivery enhancers. PMID:19363796

  5. Combination of the LSQR method and a genetic algorithm for solving the electrocardiography inverse problem

    NASA Astrophysics Data System (ADS)

    Jiang, Mingfeng; Xia, Ling; Shou, Guofa; Tang, Min

    2007-03-01

    Computing epicardial potentials from body surface potentials constitutes one form of ill-posed inverse problem of electrocardiography (ECG). To solve this ECG inverse problem, the Tikhonov regularization and truncated singular-value decomposition (TSVD) methods have been commonly used to overcome the ill-posed property by imposing constraints on the magnitudes or derivatives of the computed epicardial potentials. Such direct regularization methods, however, are impractical when the transfer matrix is large. The least-squares QR (LSQR) method, one of the iterative regularization methods based on Lanczos bidiagonalization and QR factorization, has been shown to be numerically more reliable in various circumstances than the other methods considered. This LSQR method, however, to our knowledge, has not been introduced and investigated for the ECG inverse problem. In this paper, the regularization properties of the Krylov subspace iterative method of LSQR for solving the ECG inverse problem were investigated. Due to the 'semi-convergence' property of the LSQR method, the L-curve method was used to determine the stopping iteration number. The performance of the LSQR method for solving the ECG inverse problem was also evaluated based on a realistic heart-torso model simulation protocol. The results show that the inverse solutions recovered by the LSQR method were more accurate than those recovered by the Tikhonov and TSVD methods. In addition, by combing the LSQR with genetic algorithms (GA), the performance can be improved further. It suggests that their combination may provide a good scheme for solving the ECG inverse problem.

  6. Hypersingular meshless method using double-layer potentials for three-dimensional exterior acoustic problems.

    PubMed

    Young, D L; Chen, K H; Liu, T Y; Wu, C S

    2016-01-01

    Three-dimensional exterior acoustic problems with irregular domains are solved using a hypersingular meshless method. In particular, the method of fundamental solutions (MFS) is used to formulate and analyze such acoustic problems. It is well known that source points for MFS cannot be located on the real boundary due to the singularity of the kernel functions. Thus, the diagonal terms of the influence matrices are unobtainable when source points are located on the boundary. An efficient approach is proposed to overcome such difficulties, when the MFS is used for three-dimensional exterior acoustic problems. This work is an extension of previous research on two-dimensional problems. The solution of the problem is expressed in terms of a double-layer potential representation on the physical boundary. Three examples are presented in which the proposed method is compared to the MFS and boundary element method. Good numerical performance is demonstrated by the proposed hypersingular meshless method. PMID:26827046

  7. On the Model and Solution Methods for Multi-Facility Capacity Expansion Problem

    NASA Astrophysics Data System (ADS)

    Magori, Hideki; Yokoyama, Ryuichi

    Capacity expansion problem is a hard combinatorial problem to solve because it must treat many scheduling subproblems within a multi-facility framework. It is classified into a category of general Investment & Operation planning problems. This paper presents a basic model for a certain class of capacity expansion problem applicable to the generation expansion problem in power systems, and proposes several mathematical methods for the model. In the field of Operational Research, Dynamic Programming (DP) has been the most popular method under multistage dynamic environments. It is however made clear in the paper that the model cannot be exactly solved by standard DPs. Consequently, another representative methods such as Lagrangian Relaxation, Branch-and-Bound and Heuristics are also tailored as alternatives for DP and compared with each other. Computational experiments by all proposed methods yielded promising suboptima with quality guarantee, among others Branch-and-Bound and Lagrangian Relaxation methods are recommended as suitable ones for the model.

  8. The Off-Campus Environment: Approaches for Reducing Alcohol and Other Drug Problems. Prevention Updates

    ERIC Educational Resources Information Center

    DeJong, William; Vehige, Tamara

    2008-01-01

    The presence of a college or university in a community can greatly enrich the lives of long-term residents, intellectually, culturally, and financially. But students who live, work, and play in nearby neighborhoods can sometimes create enormous problems, putting a strain on campus and community relations and compromising the health and safety of…

  9. Relapse Prevention for Alcohol and Drug Problems: That Was Zen, This Is Tao

    ERIC Educational Resources Information Center

    Witkiewitz, Katie; Marlatt, Alan G.

    2004-01-01

    Relapse prevention, based on the cognitive-behavioral model of relapse, has become an adjunct to the treatment of numerous psychological problems, including (but not limited to) substance abuse, depression, sexual offending, and schizophrenia. This article provides an overview of the efficacy and effectiveness of relapse prevention in the…

  10. It's More than Drinking, Drugs, and Sex: College Student Perceptions of Family Problems

    ERIC Educational Resources Information Center

    Gorsline, Denise; Holl, Andrea; Pearson, Judy C.; Child, Jeffrey T.

    2006-01-01

    The colorful misbehavior of college students trumps considerations of college students' relationships with their families. With broad coverage of behaviors such as binge drinking, on-line gambling, and risky sexual behavior, the image of the college student is one of a person worrying about what time the bar opens, rather than problems at home.…

  11. Drugs, Devices, and Desires: A Problem-Based Learning Course in the History of Medicine

    ERIC Educational Resources Information Center

    Levitt, Sarah; McKeage, Anne; Rangachari, P. K.

    2013-01-01

    Problem-based learning (PBL) is well suited for courses in the history of medicine, where multiple perspectives exist and information has to be gleaned from different sources. A student, an archivist, and a teacher offer three perspectives about a senior level course where students explored the antecedents and consequences of medical technology.…

  12. Analyzing elastoplastic large deformation problems with the complex variable element-free Galerkin method

    NASA Astrophysics Data System (ADS)

    Li, D. M.; Liew, K. M.; Cheng, Y. M.

    2014-06-01

    Using the complex variable moving least-squares (CVMLS) approximation, a complex variable element-free Galerkin (CVEFG) method for two-dimensional elastoplastic large deformation problems is presented. This meshless method has higher computational precision and efficiency because in the CVMLS approximation, the trial function of a two-dimensional problem is formed with a one-dimensional basis function. For two-dimensional elastoplastic large deformation problems, the Galerkin weak form is employed to obtain its equation system. The penalty method is used to impose essential boundary conditions. Then the corresponding formulae of the CVEFG method for two-dimensional elastoplastic large deformation problems are derived. In comparison with the conventional EFG method, our study shows that the CVEFG method has higher precision and efficiency. For illustration purpose, a few selected numerical examples are presented to demonstrate the advantages of the CVEFG method.

  13. Drugs of abuse detection in saliva based on actuated optical method

    NASA Astrophysics Data System (ADS)

    Shao, Jie; Li, Zhenyu; Jiang, Hong; Wang, Wenlong; Wu, Yixuan

    2014-12-01

    There has been a considerable increase in the abuse of drugs during the past decade. Combing drug use with driving is very dangerous. More than 11% of drivers in a roadside survey tested positive for drugs, while 18% of drivers killed in accidents tested positive for drugs as reported in USA, 2007. Toward developing a rapid drug screening device, we use saliva as the sample, and combining the traditional immunoassays method with optical magnetic technology. There were several methods for magnetic nanoparticles detection, such as magnetic coils, SQUID, microscopic imaging, and Hall sensors. All of these methods were not suitable for our demands. By developing a novel optical scheme, we demonstrate high-sensitivity detection in saliva. Drugs of abuse are detected at sub-nano gram per milliliter levels in less than 120 seconds. Evanescent wave principle has been applied to sensitively monitor the presence of magnetic nanoparticles on the binding surface. Like the total internal reflection fluorescence microscope (TIRFM), evanescent optical field is generated at the plastic/fluid interface, which decays exponentially and penetrates into the fluid by only a sub-wavelength distance. By disturbance total internal reflection with magnetic nanoparticles, the optical intensity would be influenced. We then detected optical output by imaging the sensor surface onto a CCD camera. We tested four drugs tetrahydrocannabinol (THC), methamphetamine (MAMP), ketamine (KET), morphine (OPI), using this technology. 100 ng mL-1 sensitivity was achieved, and obvious evidence showed that this results could be improved in further researches.

  14. Developments in Methods for Measuring the Intestinal Absorption of Nanoparticle-Bound Drugs.

    PubMed

    Liu, Wei; Pan, Hao; Zhang, Caiyun; Zhao, Liling; Zhao, Ruixia; Zhu, Yongtao; Pan, Weisan

    2016-01-01

    With the rapid development of nanotechnology, novel drug delivery systems comprising orally administered nanoparticles (NPs) have been paid increasing attention in recent years. The bioavailability of orally administered drugs has significant influence on drug efficacy and therapeutic dosage, and it is therefore imperative that the intestinal absorption of oral NPs be investigated. This review examines the various literature on the oral absorption of polymeric NPs, and provides an overview of the intestinal absorption models that have been developed for the study of oral nanoparticles. Three major categories of models including a total of eight measurement methods are described in detail (in vitro: dialysis bag, rat gut sac, Ussing chamber, cell culture model; in situ: intestinal perfusion, intestinal loops, intestinal vascular cannulation; in vivo: the blood/urine drug concentration method), and the advantages and disadvantages of each method are contrasted and elucidated. In general, in vitro and in situ methods are relatively convenient but lack accuracy, while the in vivo method is troublesome but can provide a true reflection of drug absorption in vivo. This review summarizes the development of intestinal absorption experiments in recent years and provides a reference for the systematic study of the intestinal absorption of nanoparticle-bound drugs. PMID:27455239

  15. Developments in Methods for Measuring the Intestinal Absorption of Nanoparticle-Bound Drugs

    PubMed Central

    Liu, Wei; Pan, Hao; Zhang, Caiyun; Zhao, Liling; Zhao, Ruixia; Zhu, Yongtao; Pan, Weisan

    2016-01-01

    With the rapid development of nanotechnology, novel drug delivery systems comprising orally administered nanoparticles (NPs) have been paid increasing attention in recent years. The bioavailability of orally administered drugs has significant influence on drug efficacy and therapeutic dosage, and it is therefore imperative that the intestinal absorption of oral NPs be investigated. This review examines the various literature on the oral absorption of polymeric NPs, and provides an overview of the intestinal absorption models that have been developed for the study of oral nanoparticles. Three major categories of models including a total of eight measurement methods are described in detail (in vitro: dialysis bag, rat gut sac, Ussing chamber, cell culture model; in situ: intestinal perfusion, intestinal loops, intestinal vascular cannulation; in vivo: the blood/urine drug concentration method), and the advantages and disadvantages of each method are contrasted and elucidated. In general, in vitro and in situ methods are relatively convenient but lack accuracy, while the in vivo method is troublesome but can provide a true reflection of drug absorption in vivo. This review summarizes the development of intestinal absorption experiments in recent years and provides a reference for the systematic study of the intestinal absorption of nanoparticle-bound drugs. PMID:27455239

  16. Microparticles Produced by the Hydrogel Template Method for Sustained Drug Delivery

    PubMed Central

    Lu, Ying; Sturek, Michael; Park, Kinam

    2014-01-01

    Polymeric microparticles have been used widely for sustained drug delivery. Current methods of microparticle production can be improved by making homogeneous particles in size and shape, increasing the drug loading, and controlling the initial burst release. In the current study, the hydrogel template method was used to produce homogeneous poly(lactide-co-glycolide) (PLGA) microparticles and to examine formulation and process-related parameters. Poly(vinyl alcohol) (PVA) was used to make hydrogel templates. The parameters examined include PVA molecular weight, type of PLGA (as characterized by lactide content, inherent viscosity), polymer concentration, drug concentration and composition of solvent system. Three model compounds studied were risperidone, methylprednisolone acetate and paclitaxel. The ability of the hydrogel template method to produce microparticles with good conformity to template was dependent on molecular weight of PVA and viscosity of the PLGA solution. Drug loading and encapsulation efficiency were found to be influenced by PLGA lactide content, polymer concentration and composition of the solvent system. The drug loading and encapsulation efficiency were 28.7% and 82% for risperidone, 31.5% and 90% for methylprednisolone acetate, and 32.2 % and 92 % for paclitaxel, respectively. For all three drugs, release was sustained for weeks, and the in vitro release profile of risperidone was comparable to that of microparticles prepared using the conventional emulsion method. The hydrogel template method provides a new approach of manipulating microparticles. PMID:24333903

  17. Similarity-based machine learning methods for predicting drug-target interactions: a brief review.

    PubMed

    Ding, Hao; Takigawa, Ichigaku; Mamitsuka, Hiroshi; Zhu, Shanfeng

    2014-09-01

    Computationally predicting drug-target interactions is useful to select possible drug (or target) candidates for further biochemical verification. We focus on machine learning-based approaches, particularly similarity-based methods that use drug and target similarities, which show relationships among drugs and those among targets, respectively. These two similarities represent two emerging concepts, the chemical space and the genomic space. Typically, the methods combine these two types of similarities to generate models for predicting new drug-target interactions. This process is also closely related to a lot of work in pharmacogenomics or chemical biology that attempt to understand the relationships between the chemical and genomic spaces. This background makes the similarity-based approaches attractive and promising. This article reviews the similarity-based machine learning methods for predicting drug-target interactions, which are state-of-the-art and have aroused great interest in bioinformatics. We describe each of these methods briefly, and empirically compare these methods under a uniform experimental setting to explore their advantages and limitations. PMID:23933754

  18. [Comparison of discriminative methods of hypoglycemic drugs by Raman spectroscopy].

    PubMed

    Gao, Qun; Zhang, Zhong-Hu; Lu, Feng

    2012-12-01

    In the present paper, four kinds of cluster analysis methods were used in rapid, non-destructive discrimination of hypoglycemic tablets by the Raman spectroscopy technology. Nine kinds of hypoglycemic tablets, including 48 samples, were determined using a Raman spectrometer. The sample data were pretreated with the methods of frequency range cutting, baseline correction, smoothing and vector normalization, then were analyzed by K-means, hierachical cluster, self-organizing maps (SOM) and PCA-SOM respectively. The results demonstrated that SOM was better than K-means and hierachical cluster, and it provided the best discrimination when combined with PCA. The research offers a new approach to the rapid discrimination of different kinds of hypoglycemic tablets. PMID:23427547

  19. [Execute Yinpian drug catalogue, traditional Chinese medicine Yinpian prescription dispensing rule, completely solve the problem of the dispensing specified varieties].

    PubMed

    Huang, Zongqiang

    2011-07-01

    For solve confusion of the dispensing specified varieties of traditional Chinese medicine Yinpian, the state administration of traditional Chinese medicine had decreed in 2009 the on the Traditional Chinese Medicine Yinpian prescription name and the dispensing specified varieties notification, Require various regions medical institutions to solve the problem. But the notification permit that each medical institutions formulate the traditional Chinese medicine Yinpian prescription name and standards of the dispensing Specified varieties, be sure to cause each medical institutions on parallel tracks in the dispensing Specified varieties. Beijing the Beijing traditional Chinese medicine Yinpian prescription dispensing rule. It nor did completely solve the problem of the dispensing specified varieties, there is a difference between doctor and harmacist. So formulate statute universal and scientific, Completely solve the problem of the dispensing specified varieties, It is Long-cherished wish of government and traditional Chinese medicine sector for many years The article on appearance of the dispensing specified varieties problem, and think about actual statute of the dispensing specified varieties, and discuss Solving system, consider formulate and execute Yinpian drug catalogue and Chinese medicine Yinpian prescription dispensing rule by country and local two level, It provides legal protection to thoroughly resolve the dispensing Specified varieties Both can resolve that prescription of traditional Chinese medicine Yinpian unified provisioning in entire country, And conducive to defend local medical genre medication features, and defend precious local features processing varieties and conducive to exploit new drug, and conducive to inherit and evolve traditional Chinese medicine scientifically, It is simple and feasible final way to Chinese medicine Yinpian dispensing specified varieties. PMID:22016978

  20. A Qualitative Approach to a Better Understanding of the Problems Underlying Drug Shortages, as Viewed from Belgian, French and the European Union's Perspectives.

    PubMed

    Bogaert, Petronille; Bochenek, Tomasz; Prokop, Anna; Pilc, Andrzej

    2015-01-01

    The problem of drug shortages has been reported worldwide, gaining prominence in multiple domains and several countries in recent years. The aim of the study was to analyze, characterise and assess this problem in Belgium and France, while also adopting a wider perspective from the European Union. A qualitative methodological approach was employed, including semi-structured interviews with the representatives of respective national health authorities, pharmaceutical companies and wholesalers, as well as hospital and community pharmacists. The research was conducted in early 2014. Four themes, which were identified through the interviews, were addressed in the paper, i.e. a) defining drug shortages, b) their dynamics and perception, c) their determinants, d) the role of the European and national institutions in coping with the problem. Three groups of determinants of drug shortages were identified throughout this study: manufacturing problems, distribution and supply problems, and problems related to economic aspects. Currently, the Member States of the European Union are striving to resolve the problem very much on their own, although a far more focused and dedicated collaboration may well prove instrumental in coping with drug shortages throughout Europe more effectively. To the best of the authors' knowledge, this is the first qualitative study to investigate the characteristics, key determinants, and the problem drivers of drug shortages, focusing on this particular group of countries, while also adopting the European Union's perspective. PMID:25942432

  1. A Qualitative Approach to a Better Understanding of the Problems Underlying Drug Shortages, as Viewed from Belgian, French and the European Union’s Perspectives

    PubMed Central

    Prokop, Anna; Pilc, Andrzej

    2015-01-01

    The problem of drug shortages has been reported worldwide, gaining prominence in multiple domains and several countries in recent years. The aim of the study was to analyze, characterise and assess this problem in Belgium and France, while also adopting a wider perspective from the European Union. A qualitative methodological approach was employed, including semi-structured interviews with the representatives of respective national health authorities, pharmaceutical companies and wholesalers, as well as hospital and community pharmacists. The research was conducted in early 2014. Four themes, which were identified through the interviews, were addressed in the paper, i.e. a) defining drug shortages, b) their dynamics and perception, c) their determinants, d) the role of the European and national institutions in coping with the problem. Three groups of determinants of drug shortages were identified throughout this study: manufacturing problems, distribution and supply problems, and problems related to economic aspects. Currently, the Member States of the European Union are striving to resolve the problem very much on their own, although a far more focused and dedicated collaboration may well prove instrumental in coping with drug shortages throughout Europe more effectively. To the best of the authors’ knowledge, this is the first qualitative study to investigate the characteristics, key determinants, and the problem drivers of drug shortages, focusing on this particular group of countries, while also adopting the European Union’s perspective. PMID:25942432

  2. WebMail versus WebApp: Comparing Problem-Based Learning Methods in a Business Research Methods Course

    ERIC Educational Resources Information Center

    Williams van Rooij, Shahron

    2007-01-01

    This study examined the impact of two Problem-Based Learning (PBL) approaches on knowledge transfer, problem-solving self-efficacy, and perceived learning gains among four intact classes of adult learners engaged in a group project in an online undergraduate business research methods course. With two of the classes using a text-only PBL workbook…

  3. A Problem Decompostion Method for Efficient Diagnosis and Interpretation of Multiple Disorders

    PubMed Central

    Wu, Thomas D.

    1990-01-01

    Diagnosis of multiple disorders can be made more efficient by reasoning explicitly about problem decompositions. A diagnostic problem can be decomposed by hypothesising about the common causes and disjoint causes among the given symptoms. The resulting structure exploits computational principles of causal intersection and subproblem independence to increase efficiency. By assigning structure to a problem, the problem decomposition approach offers a new type of decision support called symptom interpretation. Problem decompositions can be computed using a symptom clustering algorithm. Experimental results indicate that symptom clustering yields substantial increases in performance compared to existing methods for multidisorder diagnosis.

  4. Application of adomian decomposition method for singularly perturbed fourth order boundary value problems

    NASA Astrophysics Data System (ADS)

    Deniz, Sinan; Bildik, Necdet

    2016-06-01

    In this paper, we use Adomian Decomposition Method (ADM) to solve the singularly perturbed fourth order boundary value problem. In order to make the calculation process easier, first the given problem is transformed into a system of two second order ODEs, with suitable boundary conditions. Numerical illustrations are given to prove the effectiveness and applicability of this method in solving these kinds of problems. Obtained results shows that this technique provides a sequence of functions which converges rapidly to the accurate solution of the problems.

  5. Comparative Study of Different Methods for the Prediction of Drug-Polymer Solubility.

    PubMed

    Knopp, Matthias Manne; Tajber, Lidia; Tian, Yiwei; Olesen, Niels Erik; Jones, David S; Kozyra, Agnieszka; Löbmann, Korbinian; Paluch, Krzysztof; Brennan, Claire Marie; Holm, René; Healy, Anne Marie; Andrews, Gavin P; Rades, Thomas

    2015-09-01

    In this study, a comparison of different methods to predict drug-polymer solubility was carried out on binary systems consisting of five model drugs (paracetamol, chloramphenicol, celecoxib, indomethacin, and felodipine) and polyvinylpyrrolidone/vinyl acetate copolymers (PVP/VA) of different monomer weight ratios. The drug-polymer solubility at 25 °C was predicted using the Flory-Huggins model, from data obtained at elevated temperature using thermal analysis methods based on the recrystallization of a supersaturated amorphous solid dispersion and two variations of the melting point depression method. These predictions were compared with the solubility in the low molecular weight liquid analogues of the PVP/VA copolymer (N-vinylpyrrolidone and vinyl acetate). The predicted solubilities at 25 °C varied considerably depending on the method used. However, the three thermal analysis methods ranked the predicted solubilities in the same order, except for the felodipine-PVP system. Furthermore, the magnitude of the predicted solubilities from the recrystallization method and melting point depression method correlated well with the estimates based on the solubility in the liquid analogues, which suggests that this method can be used as an initial screening tool if a liquid analogue is available. The learnings of this important comparative study provided general guidance for the selection of the most suitable method(s) for the screening of drug-polymer solubility. PMID:26214347

  6. A method to determine the ability of drugs to diffuse through the blood-brain barrier.

    PubMed Central

    Seelig, A; Gottschlich, R; Devant, R M

    1994-01-01

    A method has been devised for predicting the ability of drugs to cross the blood-brain barrier. The criteria depend on the amphiphilic properties of a drug as reflected in its surface activity. The assessment was made with various drugs that either penetrate or do not penetrate the blood-brain barrier. The surface activity of these drugs was quantified by their Gibbs adsorption isotherms in terms of three parameters: (i) the onset of surface activity, (ii) the critical micelle concentration, and (iii) the surface area requirement of the drug at the air/water interface. A calibration diagram is proposed in which the critical micelle concentration is plotted against the concentration required for the onset of surface activity. Three different regions are easily distinguished in this diagram: a region of very hydrophobic drugs which fail to enter the central nervous system because they remain adsorbed to the membrane, a central area of less hydrophobic drugs which can cross the blood-brain barrier, and a region of relatively hydrophilic drugs which do not cross the blood-brain barrier unless applied at high concentrations. This diagram can be used to predict reliably the central nervous system permeability of an unknown compound from a simple measurement of its Gibbs adsorption isotherm. PMID:8278409

  7. Methods to Evaluate Biliary Excretion of Drugs in Humans: an Updated Review

    PubMed Central

    Ghibellini, Giulia; Leslie, Elaine M.; Brouwer, Kim L.R.

    2008-01-01

    Determining the biliary clearance of drugs in humans is very challenging because bile in not readily accessible due to the anatomy of the hepatobiliary tract. The collection of bile usually is limited to post-surgical patients with underlying hepatobiliary disease. In healthy subjects, feces typically are used as a surrogate to quantify the amount of drug excreted via non-urinary pathways. Nevertheless, it is very important to characterize hepatobiliary elimination because this is a potential site of drug interactions that might result in significant alterations in systemic or hepatic exposure. In addition to the determination of in vivo biliary clearance values of drugs, the availability of in vitro models that can predict the extent of biliary excretion of drugs in humans may be a powerful tool in the pre-clinical stages of drug development. In this review, recent advances in the most commonly used in vivo methods to estimate biliary excretion of drugs in humans are outlined. Additionally, in vitro models that can be employed to investigate the molecular processes involved in biliary excretion are discussed to present an updated picture of the new tools and techniques that are available to study the complex processes involved in hepatic drug transport. PMID:16749853

  8. [Drug injection method risky for transmission of blood-borne diseases: are we careful enough?].

    PubMed

    Bravo Portela, M J; Ortiz Castro, A; Galván Reyes, J; Barrio Anta, G; de la Fuente de Hoz, L

    1998-01-01

    In the last 20 years, research on the determinants of the HIV epidemic among drug users has focused mainly on studies of risk behaviour for drug injection. Studies involving human behaviour present special methodological problems. This paper presents a review of 1) the most important features that make this field different from the study of blood-borne diseases in other populations, and 2) the basic variables used in epidemiology to analyse injecting risk behaviour. Alternatives to improve research planning and results are proposed based on collaborating with other disciplines and improving the methodological resources of epidemiology. PMID:9810835

  9. Evaluation of a proposed method for representing drug terminology.

    PubMed

    Cimino, J J; McNamara, T J; Meredith, T; Broverman, C A; Eckert, K C; Moore, M; Tyree, D J

    1999-01-01

    In the absence of a single, standard, multipurpose terminology for representing medications, the HL7 Vocabulary Technical Committee has sought to develop a model for such terms in a way that will provide a unified method for representing them and supporting interoperability among various terminology systems. We evaluated the preliminary model by obtaining terms, represented in our model, from three leading vendors of pharmacy system knowledge bases. A total of 2303 terms were obtained, and 3982 pair-wise comparisons were possible. We found that the components of the term descriptions matched 68-87% of the time and that the overall descriptions matched 53% of the time. The evaluation has identified a number of areas in the model where more rigorous definitions will be needed in order to improve the matching rate. This paper discusses the implications of these results. PMID:10566318

  10. A mapping method for the gravitational few-body problem with dissipation

    NASA Technical Reports Server (NTRS)

    Malhotra, Renu

    1994-01-01

    Recently a new class of numerical integration methods - 'mixed variable symplectic integrators' - has been introduced for studying long-term evolution in the conservative gravitational few-body problem. These integrators are an order of magnitude faster than conventional ordinary differential equations (ODE) integration methods. Here we present a simple modification of this method to include small non-gravitational forces. The new scheme provides a similar advantage of computational speed for a larger class of problems in Solar System dynamics.

  11. Proton nuclear magnetic resonance spectroscopy (NMR) methods for determining the purity of reference drug standards and illicit forensic drug seizures.

    PubMed

    Hays, Patrick A

    2005-11-01

    A rapid, sensitive, accurate, precise, reproducible, and versatile method for determining the purity of reference drug standards and the routine analysis of illicit drugs and adulterants using proton (1H) Nuclear Magnetic Resonance (NMR) Spectroscopy is presented. The methodology uses a weighed sample dissolved in a deuterated solvent or solvent mixture containing a high purity internal standard. The NMR experiment employs 8 scans using a 45 second delay and 90 degrees pulse. In the determination of purity of reference standards, the number of quantitative determinations available is equal to the number of peak groups that are baseline resolved. The relative standard deviation (RSD) of these signals is usually < 1% for pure standards, and the results agree well with other purity determining methods. This method can also aid in the determination of correct molecular weight for standards containing an unknown number of waters of hydration or an unknown number of acids per drug in salts. Because the molar response for the hydrogen nucleus is 1 for all compounds, and since no separation media are used, only one linearity study is required to test a probe. In the presented study, the linearity of the NMR probe was determined using methamphetamine HCl dissolved in deuterium oxide (D2O) with maleic acid as the internal standard (5 mg) for a range of concentrations from 0.033 to 69.18 mg/ml with a resulting correlation coefficient of >0.9999 for all 6 methamphetamine peak groups. The spectra of complex illicit heroin, methamphetamine, MDMA, and cocaine samples are presented, as well as an extensive list of compounds, their solubilities and the solvent(s) and internal standard used. PMID:16382828

  12. Methods Development for Blood Borne Macrophage Carriage of Nanoformulated Antiretroviral Drugs

    PubMed Central

    Roy, Upal; Martinez-Skinner, Andrea; McMillan, JoEllyn; Gendelman, Howard E.

    2010-01-01

    Nanoformulated drugs can improve pharmacodynamics and bioavailability while serving also to reduce drug toxicities for antiretroviral (ART) medicines. To this end, our laboratory has applied the principles of nanomedicine to simplify ART regimens and as such reduce toxicities while improving compliance and drug pharmacokinetics. Simple and reliable methods for manufacturing nanoformulated ART (nanoART) are shown. Particles of pure drug are encapsulated by a thin layer of surfactant lipid coating and produced by fractionating larger drug crystals into smaller ones by either wet milling or high-pressure homogenization. In an alternative method free drug is suspended in a droplet of a polymer. Herein, drug is dissolved within a polymer then agitated by ultrasonication until individual nanosized droplets are formed. Dynamic light scattering and microscopic examination characterize the physical properties of the particles (particle size, charge and shape). Their biologic properties (cell uptake and retention, cytotoxicity and antiretroviral efficacy) are determined with human monocyte-derived macrophages (MDM). MDM are derived from human peripheral blood monocytes isolated from leukopacks using centrifugal elutriation for purification. Such blood-borne macrophages may be used as cellular transporters for nanoART distribution to human immunodeficiency virus (HIV) infected organs. We posit that the repackaging of clinically available antiretroviral medications into nanoparticles for HIV-1 treatments may improve compliance and positively affect disease outcomes. PMID:21178968

  13. Triptans in the treatment of migraine: drug selection by means of the SOJA method.

    PubMed

    Janknegt, Robert

    2007-10-01

    In this paper, drug selection of triptans for the treatment of migraine is performed by means of the SOJA method, which prospectively defines and scores selection criteria. All drugs available in the Netherlands were included in the analysis. The following selection criteria were used (relative weight between brackets): approved indications (40), number of formulations (50), variability of bioavailability (40), drug interactions (85), clinical efficacy (415), side effects (190), acquisition cost (75) and documentation (105). Almotriptan, rizatriptan and sumatriptan show the highest scores, and are the most suitable triptans for formulary inclusion. PMID:17931075

  14. Drug Reactions

    MedlinePlus

    ... problem is interactions, which may occur between Two drugs, such as aspirin and blood thinners Drugs and food, such as statins and grapefruit Drugs and supplements, such as gingko and blood thinners ...

  15. Ecological Momentary Assessment of Illicit Drug Use Compared to Biological and Self-Reported Methods

    PubMed Central

    Genz, Andrew; Westergaard, Ryan P; Chang, Larry W; Bollinger, Robert C; Latkin, Carl; Kirk, Gregory D

    2016-01-01

    Background The use of mHealth methods for capturing illicit drug use and associated behaviors have become more widely used in research settings, yet there is little research as to how valid these methods are compared to known measures of capturing and quantifying drug use. Objective We examined the concordance of ecological momentary assessment (EMA) of drug use to previously validated biological and audio-computer assisted self-interview (ACASI) methods. Methods The Exposure Assessment in Current Time (EXACT) study utilized EMA methods to assess drug use in real-time in participants’ natural environments. Utilizing mobile devices, participants self-reported each time they used heroin or cocaine over a 4-week period. Each week, PharmChek sweat patch samples were collected for measurement of heroin and cocaine and participants answered an ACASI-based questionnaire to report behaviors and drug using events during the prior week. Reports of cocaine and heroin use captured through EMA were compared to weekly biological or self-report measures through percent agreement and concordance correlation coefficients to account for repeated measures. Correlates of discordance were obtained from logistic regression models. Results A total of 109 participants were a median of 48.5 years old, 90% African American, and 52% male. During 436 person-weeks of observation, we recorded 212 (49%) cocaine and 103 (24%) heroin sweat patches, 192 (44%) cocaine and 161 (37%) heroin ACASI surveys, and 163 (37%) cocaine and 145 (33%) heroin EMA reports. The percent agreement between EMA and sweat patch methods was 70% for cocaine use and 72% for heroin use, while the percent agreement between EMA and ACASI methods was 77% for cocaine use and 79% for heroin use. Misreporting of drug use by EMA compared to sweat patch and ACASI methods were different by illicit drug type. Conclusions Our work demonstrates moderate to good agreement of EMA to biological and standard self-report methods in

  16. Hybrid method of deterministic and probabilistic approaches for multigroup neutron transport problem

    SciTech Connect

    Lee, D.

    2012-07-01

    A hybrid method of deterministic and probabilistic methods is proposed to solve Boltzmann transport equation. The new method uses a deterministic method, Method of Characteristics (MOC), for the fast and thermal neutron energy ranges and a probabilistic method, Monte Carlo (MC), for the intermediate resonance energy range. The hybrid method, in case of continuous energy problem, will be able to take advantage of fast MOC calculation and accurate resonance self shielding treatment of MC method. As a proof of principle, this paper presents the hybrid methodology applied to a multigroup form of Boltzmann transport equation and confirms that the hybrid method can produce consistent results with MC and MOC methods. (authors)

  17. Nonlinear Schwarz-Fas Methods for Unstructured Finite Element Elliptic Problems

    SciTech Connect

    Jones, J E; Vassilevski, P S; Woodward, C S

    2002-09-30

    This paper provides extensions of an element agglomeration AMG method to nonlinear elliptic problems discretized by the finite element method on general unstructured meshes. The method constructs coarse discretization spaces and corresponding coarse nonlinear operators as well as their Jacobians. We introduce both standard (fairly quasi-uniformly coarsened) and non-standard (coarsened away) coarse meshes and respective finite element spaces. We use both kind of spaces in FAS type coarse subspace correction (or Schwarz) algorithms. Their performance is illustrated on a number of model problems. The coarsened away spaces seem to perform better than the standard spaces for problems with nonlinearities in the principal part of the elliptic operator.

  18. Statistical method for resolving the photon-photoelectron-counting inversion problem

    SciTech Connect

    Wu Jinlong; Li Tiejun; Peng, Xiang; Guo Hong

    2011-02-01

    A statistical inversion method is proposed for the photon-photoelectron-counting statistics in quantum key distribution experiment. With the statistical viewpoint, this problem is equivalent to the parameter estimation for an infinite binomial mixture model. The coarse-graining idea and Bayesian methods are applied to deal with this ill-posed problem, which is a good simple example to show the successful application of the statistical methods to the inverse problem. Numerical results show the applicability of the proposed strategy. The coarse-graining idea for the infinite mixture models should be general to be used in the future.

  19. A Proposal of Operational Risk Management Method Using FMEA for Drug Manufacturing Computerized System

    NASA Astrophysics Data System (ADS)

    Takahashi, Masakazu; Nanba, Reiji; Fukue, Yoshinori

    This paper proposes operational Risk Management (RM) method using Failure Mode and Effects Analysis (FMEA) for drug manufacturing computerlized system (DMCS). The quality of drug must not be influenced by failures and operational mistakes of DMCS. To avoid such situation, DMCS has to be conducted enough risk assessment and taken precautions. We propose operational RM method using FMEA for DMCS. To propose the method, we gathered and compared the FMEA results of DMCS, and develop a list that contains failure modes, failures and countermeasures. To apply this list, we can conduct RM in design phase, find failures, and conduct countermeasures efficiently. Additionally, we can find some failures that have not been found yet.

  20. Analysis of the 3D acoustic cloaking problems using optimization method

    NASA Astrophysics Data System (ADS)

    Alekseev, G. V.; Spivak, Yu E.

    2016-06-01

    Control problems for the 3D model of acoustic scattering which describes scattering acoustic waves by a permeable obstacle with the form of a spherical layer are considered. These problems arise while developing the design technologies of acoustic cloaking devices using the wave flow method. The solvability of direct and control problems for the acoustic scattering model under study is proved. The sufficient conditions which provide local uniqueness and stability of optimal solutions are established.

  1. In silico Prediction of Drug Induced Liver Toxicity Using Substructure Pattern Recognition Method.

    PubMed

    Zhang, Chen; Cheng, Feixiong; Li, Weihua; Liu, Guixia; Lee, Philip W; Tang, Yun

    2016-04-01

    Drug-induced liver injury (DILI) is a leading cause of acute liver failure in the US and less severe liver injury worldwide. It is also one of the major reasons of drug withdrawal from the market. Thus, DILI has become one of the most important concerns of drugs, and should be predicted in very early stage of drug discovery process. In this study, a comprehensive data set containing 1317 diverse compounds was collected from publications. Then, high accuracy classification models were built using five machine learning methods based on MACCS and FP4 fingerprints after evaluating by substructure pattern recognition method. The best model was built using SVM method together with FP4 fingerprint at the IG value threshold of 0.0005. Its overall predictive accuracies were 79.7 % and 64.5 % for the training and test sets, separately, which yielded overall accuracy of 75.0 % for the external validation dataset, consisting of 88 compounds collected from a benchmark DILI database - the Liver Toxicity Knowledge Base. This model could be used for drug-induced liver toxicity prediction. Moreover, some key substructure patterns correlated with drug-induced liver toxicity were also identified as structural alerts. PMID:27491923

  2. Multigrid one shot methods for optimal control problems: Infinite dimensional control

    NASA Technical Reports Server (NTRS)

    Arian, Eyal; Taasan, Shlomo

    1994-01-01

    The multigrid one shot method for optimal control problems, governed by elliptic systems, is introduced for the infinite dimensional control space. ln this case, the control variable is a function whose discrete representation involves_an increasing number of variables with grid refinement. The minimization algorithm uses Lagrange multipliers to calculate sensitivity gradients. A preconditioned gradient descent algorithm is accelerated by a set of coarse grids. It optimizes for different scales in the representation of the control variable on different discretization levels. An analysis which reduces the problem to the boundary is introduced. It is used to approximate the two level asymptotic convergence rate, to determine the amplitude of the minimization steps, and the choice of a high pass filter to be used when necessary. The effectiveness of the method is demonstrated on a series of test problems. The new method enables the solutions of optimal control problems at the same cost of solving the corresponding analysis problems just a few times.

  3. Vectorization and parallelization of the finite strip method for dynamic Mindlin plate problems

    NASA Technical Reports Server (NTRS)

    Chen, Hsin-Chu; He, Ai-Fang

    1993-01-01

    The finite strip method is a semi-analytical finite element process which allows for a discrete analysis of certain types of physical problems by discretizing the domain of the problem into finite strips. This method decomposes a single large problem into m smaller independent subproblems when m harmonic functions are employed, thus yielding natural parallelism at a very high level. In this paper we address vectorization and parallelization strategies for the dynamic analysis of simply-supported Mindlin plate bending problems and show how to prevent potential conflicts in memory access during the assemblage process. The vector and parallel implementations of this method and the performance results of a test problem under scalar, vector, and vector-concurrent execution modes on the Alliant FX/80 are also presented.

  4. Solution of an optimal control lifting body entry problem by an improved method of perturbation functions

    NASA Technical Reports Server (NTRS)

    Garcia, F., Jr.

    1975-01-01

    This paper presents a solution to a complex lifting reentry three-degree-of-freedom problem by using the calculus of variations to minimize the integral of the sum of the aerodynamics loads and heat rate input to the vehicle. The entry problem considered does not have state and/or control constraints along the trajectory. The calculus of variations method applied to this problem gives rise to a set of necessary conditions which are used to formulate a two point boundary value (TPBV) problem. This TPBV problem is then numerically solved by an improved method of perturbation functions (IMPF) using several starting co-state vectors. These vectors were chosen so that each one had a larger norm with respect to show how the envelope of convergence is significantly increased using this method and cases are presented to point this out.

  5. The adaptive problems of female teenage refugees and their behavioral adjustment methods for coping

    PubMed Central

    Mhaidat, Fatin

    2016-01-01

    This study aimed at identifying the levels of adaptive problems among teenage female refugees in the government schools and explored the behavioral methods that were used to cope with the problems. The sample was composed of 220 Syrian female students (seventh to first secondary grades) enrolled at government schools within the Zarqa Directorate and who came to Jordan due to the war conditions in their home country. The study used the scale of adaptive problems that consists of four dimensions (depression, anger and hostility, low self-esteem, and feeling insecure) and a questionnaire of the behavioral adjustment methods for dealing with the problem of asylum. The results indicated that the Syrian teenage female refugees suffer a moderate degree of adaptation problems, and the positive adjustment methods they have used are more than the negatives. PMID:27175098

  6. A simple method for the subnanomolar quantitation of seven ophthalmic drugs in the rabbit eye.

    PubMed

    Latreille, Pierre-Luc; Banquy, Xavier

    2015-05-01

    This study describes the development and validation of a new liquid chromatography-tandem mass spectrometry (MS/MS) method capable of simultaneous quantitation of seven ophthalmic drugs-pilocarpine, lidocaine, atropine, proparacaine, timolol, prednisolone, and triamcinolone acetonide-within regions of the rabbit eye. The complete validation of the method was performed using an Agilent 1100 series high-performance liquid chromatography system coupled to a 4000 QTRAP MS/MS detector in positive TurboIonSpray mode with pooled drug solutions. The method sensitivity, evaluated by the lower limit of quantitation in two simulated matrices, yielded lower limits of quantitation of 0.25 nmol L(-1) for most of the drugs. The precision in the low, medium, and high ranges of the calibration curves, the freeze-thaw stability over 1 month, the intraday precision, and the interday precision were all within a 15% limit. The method was used to quantitate the different drugs in the cornea, aqueous humor, vitreous humor, and remaining eye tissues of the rabbit eye. It was validated to a concentration of up to 1.36 ng/g in humors and 5.43 ng/g in tissues. The unprecedented low detection limit of the present method and its ease of implementation allow easy, robust, and reliable quantitation of multiple drugs for rapid in vitro and in vivo evaluation of the local pharmacokinetics of these compounds. PMID:25749792

  7. A multiclass multiresidue LC-MS/MS method for analysis of veterinary drugs in bovine kidney

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The increased efficiency permitted by multiclass, multiresidue methods has made such approaches very attractive to laboratories involved in monitoring veterinary drug residues in animal tissues. In this current work, evaluation of a multiclass multiresidue LC-MS/MS method in bovine kidney is describ...

  8. A Neglected Population: Drug-Using Women and Women's Methods of HIV/STI Prevention

    ERIC Educational Resources Information Center

    Gollub, Erica L.

    2008-01-01

    Women drug users are at extremely high risk of HIV and sexually transmitted infections (STIs) from sexual transmission, but remain seriously neglected in intervention research promoting women-initiated methods of HIV/STI prevention. Sparse available data indicate a high interest and enthusiasm for women-initiated methods among these women.…

  9. A modified form of conjugate gradient method for unconstrained optimization problems

    NASA Astrophysics Data System (ADS)

    Ghani, Nur Hamizah Abdul; Rivaie, Mohd.; Mamat, Mustafa

    2016-06-01

    Conjugate gradient (CG) methods have been recognized as an interesting technique to solve optimization problems, due to the numerical efficiency, simplicity and low memory requirements. In this paper, we propose a new CG method based on the study of Rivaie et al. [7] (Comparative study of conjugate gradient coefficient for unconstrained Optimization, Aus. J. Bas. Appl. Sci. 5(2011) 947-951). Then, we show that our method satisfies sufficient descent condition and converges globally with exact line search. Numerical results show that our proposed method is efficient for given standard test problems, compare to other existing CG methods.

  10. A Method for Coping with Conflict in Problem-Solving Groups.

    ERIC Educational Resources Information Center

    Likert, Rensis; Likert, Jane Gibson

    1978-01-01

    The problem-solving method most often used in problem-solving groups is likely to create relationships among members of the group that will lead to a win-lose solution. To avoid this, members can list conditions they feel a solution must meet before they can accept it. (Author)

  11. A regularized Newton method for solving equilibrium programming problems with an inexactly specified set

    NASA Astrophysics Data System (ADS)

    Antipin, A. S.; Vasil'Ev, F. P.; Stukalov, A. S.

    2007-01-01

    Unstable equilibrium problems are examined in which the objective function and the set where the equilibrium point is sought are specified inexactly. A regularized Newton method, combined with penalty functions, is proposed for solving such problems, and its convergence is analyzed. A regularizing operator is constructed.

  12. Implementing a Problem-Based Learning Approach for Teaching Research Methods in Geography

    ERIC Educational Resources Information Center

    Spronken-Smith, Rachel

    2005-01-01

    This paper first describes problem-based learning; second describes how a research methods course in geography is taught using a problem-based learning approach; and finally relates student and staff experiences of this approach. The course is run through regular group meetings, two residential field trips and optional skills-based workshops.…

  13. Teaching Methods for Systematic Inventive Problem-Solving: Evaluation of a Course for Teachers

    ERIC Educational Resources Information Center

    Barak, Moshe

    2006-01-01

    Systematic inventive problem-solving is an approach for finding original and useful ideas by systematically examining alterations in existing components within a system, their attributes, functions or internal relationships. This method, which aims at complementing divergent thinking in problem-solving and design, is gaining increased attention in…

  14. Abstract Applets: A Method for Integrating Numerical Problem Solving into the Undergraduate Physics Curriculum

    SciTech Connect

    Peskin, Michael E

    2003-02-13

    In upper-division undergraduate physics courses, it is desirable to give numerical problem-solving exercises integrated naturally into weekly problem sets. I explain a method for doing this that makes use of the built-in class structure of the Java programming language. I also supply a Java class library that can assist instructors in writing programs of this type.

  15. Method of successive approximations for the solution of certain problems in aerodynamics

    NASA Technical Reports Server (NTRS)

    Shvets, M E

    1951-01-01

    A method of successive approximations for the solution of problems in the fields of diffusion, boundary-layer flow, and heat-transfer is illustrated by solving problems in each of these fields. In most of the examples, the approximate solutions are compared with known accurate solutions and the agreement is shown to be good.

  16. Marine microorganism-invertebrate assemblages: perspectives to solve the "supply problem" in the initial steps of drug discovery.

    PubMed

    Leal, Miguel Costa; Sheridan, Christopher; Osinga, Ronald; Dionísio, Gisela; Rocha, Rui Jorge Miranda; Silva, Bruna; Rosa, Rui; Calado, Ricardo

    2014-07-01

    The chemical diversity associated with marine natural products (MNP) is unanimously acknowledged as the "blue gold" in the urgent quest for new drugs. Consequently, a significant increase in the discovery of MNP published in the literature has been observed in the past decades, particularly from marine invertebrates. However, it remains unclear whether target metabolites originate from the marine invertebrates themselves or from their microbial symbionts. This issue underlines critical challenges associated with the lack of biomass required to supply the early stages of the drug discovery pipeline. The present review discusses potential solutions for such challenges, with particular emphasis on innovative approaches to culture invertebrate holobionts (microorganism-invertebrate assemblages) through in toto aquaculture, together with methods for the discovery and initial production of bioactive compounds from these microbial symbionts. PMID:24983638

  17. A numerical study of hybrid optimization methods for the molecular conformation problems

    SciTech Connect

    Meza, J.C.; Martinez, M.L.

    1993-05-01

    An important area of research in computational biochemistry is the design of molecules for specific applications. The design of these molecules depends on the accurate determination of their three-dimensional structure or conformation. Under the assumption that molecules will settle into a configuration for which their energy is at a minimum, this design problem can be formulated as a global optimization problem. The solution of the molecular conformation problem can then be obtained, at least in principle, through any number of optimization algorithms. Unfortunately, it can easily be shown that there exist a large number of local minima for most molecules which makes this an extremely difficult problem for any standard optimization method. In this study, we present results for various optimization algorithms applied to a molecular conformation problem. We include results for genetic algorithms, simulated annealing, direct search methods, and several gradient methods. The major result of this study is that none of these standard methods can be used in isolation to efficiently generate minimum energy configurations. We propose instead several hybrid methods that combine properties of several local optimization algorithms. These hybrid methods have yielded better results on representative test problems than single methods.

  18. Simultaneous determination of some cholesterol-lowering drugs in their binary mixture by novel spectrophotometric methods

    NASA Astrophysics Data System (ADS)

    Lotfy, Hayam Mahmoud; Hegazy, Maha Abdel Monem

    2013-09-01

    Four simple, specific, accurate and precise spectrophotometric methods manipulating ratio spectra were developed and validated for simultaneous determination of simvastatin (SM) and ezetimibe (EZ) namely; extended ratio subtraction (EXRSM), simultaneous ratio subtraction (SRSM), ratio difference (RDSM) and absorption factor (AFM). The proposed spectrophotometric procedures do not require any preliminary separation step. The accuracy, precision and linearity ranges of the proposed methods were determined, and the methods were validated and the specificity was assessed by analyzing synthetic mixtures containing the cited drugs. The four methods were applied for the determination of the cited drugs in tablets and the obtained results were statistically compared with each other and with those of a reported HPLC method. The comparison showed that there is no significant difference between the proposed methods and the reported method regarding both accuracy and precision.

  19. Simultaneous determination of some anti-hypertensive drugs in their binary mixture by novel spectrophotometric methods

    NASA Astrophysics Data System (ADS)

    Fayez, Yasmin Mohammed

    2014-11-01

    Three simple, accurate and precise spectrophotometric methods manipulating ratio spectra were developed and validated for simultaneous determination of Irbesartan (IRB) and Hydrochlorothiazide (HCT) without prior separation namely; ratio subtraction coupled with constant multiplication (RS-CM), ratio difference (RD) and constant center (CC). The accuracy, precision and linearity ranges of the proposed methods were determined, and the methods were validated and the specificity was assessed by analyzing synthetic mixtures containing the cited drugs. The three methods were applied for the determination of the cited drugs in tablets and the obtained results were statistically compared with each other and with those of official methods. The comparison showed that there is no significant difference between the proposed methods and the official methods regarding both accuracy and precision.

  20. Revisiting the Isobole and Related Quantitative Methods for Assessing Drug Synergism

    PubMed Central

    2012-01-01

    The isobole is well established and commonly used in the quantitative study of agonist drug combinations. This article reviews the isobole, its derivation from the concept of dose equivalence, and its usefulness in providing the predicted effect of an agonist drug combination, a topic not discussed in pharmacology textbooks. This review addresses that topic and also shows that an alternate method, called “Bliss independence,” is inconsistent with the isobolar approach and also has a less clear conceptual basis. In its simplest application the isobole is the familiar linear plot in Cartesian coordinates with intercepts representing the individual drug potencies. It is also shown that the isobole can be nonlinear, a fact recognized by its founder (Loewe) but neglected or rejected by virtually all other users. Whether its shape is linear or nonlinear the isobole is equally useful in detecting synergism and antagonism for drug combinations, and its theoretical basis leads to calculations of the expected effect of a drug combination. Numerous applications of isoboles in preclinical testing have shown that synergism or antagonism is not only a property of the two agonist drugs; the dose ratio is also important, a fact of potential importance to the design and testing of drug combinations in clinical trials. PMID:22511201