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)
Emerging drug problems in Asia
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
Problems with drugs in Croatia.
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
Community Providers’ Views of Alcohol Problems and Drug Problems
Gassman, Ruth A.; Weisner, Constance
2013-01-01
This study contrasts community health and social service providers’ views on alcohol vs. other drug abuse. A probability sample of 457 social work and other providers from a county’s public and private medical and mental health clinics, welfare and criminal justice systems, and substance abuse programs, as well as clergy, private therapists, and physicians were interviewed. For both alcohol and drug problems, providers thought only of severe dysfunctions, which suggest that less severe forms of these problems may evade detection. In addition, drug problems were viewed as more harmful than alcohol problems, which may result in providers minimizing alcohol problems. PMID:23565054
Illicit Drug Use and Problem Gambling
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
Prescription drug abuse: problem, policies, and implications.
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
Monitoring problem drug use in Bristol.
Parker, J; Pool, Y; Rawle, R; Gay, M
1988-02-01
A prospective multi-agency survey of problem drug use associated with illicit drugs and solvents in the city of Bristol in 1984-1985 found 759 problem drug users, giving a period prevalence rate of 0.4-0.8% of those aged 10-44 years. The group was a young one, with 92% under the age of 35. Over half had problems associated with opiates, mainly illicit heroin; 17% had problems associated with solvents, 9% with cannabis, 13% with stimulants, mainly illicit amphetamine, and 3% with hallucinogens. There was little indication of problematic use of barbiturates or cocaine. The problems associated with drugs and solvents were wide-ranging and not specific for individual drugs. Future community surveys would find it cost-effective to concentrate on the five best sources identified here, and to supplement these with indications of drug-taking among teenagers. The difficulties of using the definition of problem drug use for research and the value of case-register surveys for community drug monitoring are discussed. PMID:3262395
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…
Maritime drug trafficking: an underrated problem.
Aune, B R
1990-01-01
Seizure data indicate that a substantial proportion of the total quantity of drugs seized is confiscated from maritime modes of conveyance or has been transported by sea. The trafficking of narcotic drugs by sea has virtually become an industry comprised of many individual enterprises of varying size and organization. The maritime medium is one of the main ways by which drugs may enter some countries. In response to the problem, various sophisticated anti-trafficking offensives and strategies have been established or contemplated in certain geographical areas. The shipment of drugs to the primary consuming countries has not been curbed, however, and there is every indication that the overall movement of drugs is still unimpeded.
Drug problem in southeast and southwest Asia.
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
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
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
Spectral methods for discontinuous problems
NASA Technical Reports Server (NTRS)
Abarbanel, S.; Gottlieb, D.; Tadmor, E.
1985-01-01
Spectral methods yield high-order accuracy even when applied to problems with discontinuities, though not in the sense of pointwise accuracy. Two different procedures are presented which recover pointwise accurate approximations from the spectral calculations.
Computational Methods in Drug Discovery
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
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.
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…
[Designer drugs--diagnostic, psychological and low aspects of problem].
Morawska-Siudak, Jowanka; Szkolnicka, Beata; Gomółka, Ewa; Krawczyk-Pasławska, Elzbieta
2010-01-01
Designer drugs used often by teenagers have simulative, relaxing, hallucinogenic and psychedelic properties. The biological action, addictive potential, diagnostic problems and low regulations related to designer drugs are presented in the study.
Drug problems in China: recent trends, countermeasures, and challenges.
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
Multigrid Methods for EHL Problems
NASA Technical Reports Server (NTRS)
Nurgat, Elyas; Berzins, Martin
1996-01-01
In many bearings and contacts, forces are transmitted through thin continuous fluid films which separate two contacting elements. Objects in contact are normally subjected to friction and wear which can be reduced effectively by using lubricants. If the lubricant film is sufficiently thin to prevent the opposing solids from coming into contact and carries the entire load, then we have hydrodynamic lubrication, where the lubricant film is determined by the motion and geometry of the solids. However, for loaded contacts of low geometrical conformity, such as gears, rolling contact bearings and cams, this is not the case due to high pressures and this is referred to as Elasto-Hydrodynamic Lubrication (EHL) In EHL, elastic deformation of the contacting elements and the increase in fluid viscosity with pressure are very significant and cannot be ignored. Since the deformation results in changing the geometry of the lubricating film, which in turn determines the pressure distribution, an EHL mathematical model must simultaneously satisfy the complex elasticity (integral) and the Reynolds lubrication (differential) equations. The nonlinear and coupled nature of the two equations makes numerical calculations computationally intensive. This is especially true for highly loaded problems found in practice. One novel feature of these problems is that the solution may exhibit sharp pressure spikes in the outlet region. To this date both finite element and finite difference methods have been used to solve EHL problems with perhaps greater emphasis on the use of the finite difference approach. In both cases, a major computational difficulty is ensuring convergence of the nonlinear equations solver to a steady state solution. Two successful methods for achieving this are direct iteration and multigrid methods. Direct iteration methods (e.g Gauss Seidel) have long been used in conjunction with finite difference discretizations on regular meshes. Perhaps one of the best examples of
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)
The Social Construction of the Minority Drug Problem.
ERIC Educational Resources Information Center
Covington, Jeanette
1997-01-01
Examines how the minority drug problem is framed in terms of anomie and underclass models suggesting that drug subcultures in urban black areas are formed as an adaptation to aggregate community conditions. The article considers how researchers use ecological and ethnographic data to back up claims that drug subcultures are a response to inner…
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…
For Problem Drinkers, Experimental Drug Shows Promise
... the U.S. National Institute on Alcohol Abuse and Alcoholism assessed the drug in a 12-week clinical ... Services, or federal policy. More Health News on: Alcoholism and Alcohol Abuse Medicines Recent Health News Related ...
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
[An identification method for mineral drugs].
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
[Problems with the availability of drugs in The Netherlands].
Horikx, A; van Deventer, K R; Vissink, A; Bijl, D
2011-10-01
The withdrawal ofa license to trade can result in problems with the availability of drugs. The reasons for withdrawal can be ofan economic nature, but the balance between effectiveness and side effects of a drug can also, after a period of time, prove disappointing and the drug can, as a result, be withdrawn from sale. A scarcity of basic materials, too, can play a role in availability, as can the inability of the manufacturer to meet the standards of the relevant authority.
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…
Early-onset drug use and risk for drug dependence problems
Chen, Chuan-Yu; Storr, Carla L.; Anthony, James C.
2009-01-01
There is substantial evidence that alcohol, tobacco, and cannabis dependence problems surface more quickly when use of these drugs starts before adulthood, but the evidence based on other internationally regulated drugs (e.g., cocaine) is meager. With focus on an interval of up to 24 months following first drug use, we examine drug-specific and age-specific variation in profiles of early-emerging clinical features associated with drug dependence. Based upon the United States National Surveys on Drug Use and Health (NSDUH) conducted in 2000–2002, the risk of experiencing drug dependence problems was robustly greater for adolescent recent-onset users of cocaine, psychostimulant drugs other than cocaine, analgesics, anxiolytic medicines, inhalants drugs, and cannabis, as compared to adult recent-onset users (odds ratio=1.5~4.3, p<0.05). This was not the case for the NSDUH hallucinogens group (e.g., LSD). The adolescent onset associated excess risk was not constant across all clinical features. Our evidence suggests promoting earlier detection and interventions, as well as greater parent and peer awareness of drug dependence clinical features that may develop early among young people who have just started using drugs. PMID:19022584
Spectral methods for problems in complex geometries
NASA Technical Reports Server (NTRS)
Orszag, S. A.
1979-01-01
Techniques that permit the efficient application of spectral methods to solve problems in nearly arbitrary geometries are presented. These methods were found to be viable alternatives to finite difference and finite element processes. The spectral methods applied are extensions of the standard techniques of separation of variables to the solution of arbitrarily complicated problems.
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
A full multigrid method for eigenvalue problems
NASA Astrophysics Data System (ADS)
Chen, Hongtao; Xie, Hehu; Xu, Fei
2016-10-01
In this paper, a full (nested) multigrid scheme is proposed to solve eigenvalue problems. The idea here is to use a correction method to transform the eigenvalue problem solving to a series of corresponding boundary value problem solving and eigenvalue problems defined on a very low-dimensional finite element space. The boundary value problems which are defined on a sequence of multilevel finite element spaces can be solved by some multigrid iteration steps. The computational work of this new scheme can reach the same optimal order as solving the corresponding boundary value problem by the full multigrid method. Therefore, this type of full multigrid method improves the overfull efficiency of the eigenvalue problem solving.
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.
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...
Crystallization Methods for Preparation of Nanocrystals for Drug Delivery System.
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.
Regulatory Solutions to the Problem of High Generic Drug Costs
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
Methods of Drug Delivery in Neurotrauma.
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
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…
[Alcohol and drug problems in the Third World].
Mork, T
1991-06-10
The paper reviews recent development in abuse of alcohol, narcotics and psychotropic substances in developing countries. There has been a marked increase in production and sale of alcoholic beverages, and alcohol abuse has spread to new groups of the population. This has led to serious social and health problems in many developing countries. There has also been a substantial increase in abuse of narcotic drugs and psychotropic substances in some developing countries. The illicit production and traffic in narcotic drugs have resulted in more crime and corruption, and in some countries to terrorism and economic and political destabilization. The paper also summarizes activities undertaken within the UN-system in the field of alcohol and drug abuse.
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.
Phylogenetic methods in drug discovery.
Ashton, John C
2013-12-01
In recent decades, growth of computing power has facilitated powerful techniques for reconstructing evolutionary relationships from online genetic and proteomic databases. These methods are useful tools for pharmacologists for analyzing relationships between receptors and associated enzymes. Phylogenetic analysis can help generate hypotheses and leads for experimentation. Reconstruction of molecular phylogenies for the nonspecialist is described in this article using the example of the orphaned g protein coupled receptor GPR18.
Problems in the regulatory policy of the drug market
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
How the US Food and Drug Administration Can Solve the Prescription Drug Shortage Problem
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
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.
[The Swiss population and drug problems: perception of the problems and proposals for solutions].
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
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 Section 40.205 Transportation Office of the Secretary of Transportation PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Problems in Drug Tests § 40.205 How are drug test problems corrected? (a) As a collector, you have...
49 CFR 40.199 - What problems always cause a drug test to be cancelled?
Code of Federal Regulations, 2013 CFR
2013-10-01
... 49 Transportation 1 2013-10-01 2013-10-01 false What problems always cause a drug test to be... TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Problems in Drug Tests § 40.199 What problems always cause a drug test to be cancelled? (a) As the MRO, when the laboratory discovers a “fatal flaw”...
Global methods for nonlinear complementarity problems
More, J.J.
1994-04-01
Global methods for nonlinear complementarity problems formulate the problem as a system of nonsmooth nonlinear equations approach, or use continuation to trace a path defined by a smooth system of nonlinear equations. We formulate the nonlinear complementarity problem as a bound-constrained nonlinear least squares problem. Algorithms based on this formulation are applicable to general nonlinear complementarity problems, can be started from any nonnegative starting point, and each iteration only requires the solution of systems of linear equations. Convergence to a solution of the nonlinear complementarity problem is guaranteed under reasonable regularity assumptions. The converge rate is Q-linear, Q-superlinear, or Q-quadratic, depending on the tolerances used to solve the subproblems.
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…
Employment, employment-related problems, and drug use at drug court entry.
Leukefeld, Carl; McDonald, Hope Smiley; Staton, Michele; Mateyoke-Scrivner, Allison
2004-01-01
The literature indicates that employment may be an important factor for retaining substance misusing clients in treatment. Given the link between employment problems and treatment retention for Drug Court clients, the current project builds upon the existing services provided by Drug Courts in order to develop and implement an innovative model that focuses on obtaining, maintaining, and upgrading employment for Drug Court participants. The purpose of this article is to (1) describe the employment intervention used in Kentucky Drug Courts, which is grounded in established job readiness and life skill training approaches; and (2) profile those participants who were employed full-time prior to Drug Court and those who were not. Findings suggest that those employed full-time were more likely to have higher incomes and more earned income from legitimate job sources, although there were no differences in the types of employment (major jobs included food service and construction). In addition, study findings suggest that full-time employment was not "protective" since there were few differences in drug use and criminal activity by employment status. Employment interventions need to be examined to determine their utility for enhancing employment and keeping drug users in treatment. This article focuses on the initial 400 participants, who began entering the study in March, 2000.
Spectral methods for exterior elliptic problems
NASA Technical Reports Server (NTRS)
Canuto, C.; Hariharan, S. I.; Lustman, L.
1984-01-01
Spectral approximations for exterior elliptic problems in two dimensions are discussed. As in the conventional finite difference or finite element methods, the accuracy of the numerical solutions is limited by the order of the numerical farfield conditions. A spectral boundary treatment is introduced at infinity which is compatible with the infinite order interior spectral scheme. Computational results are presented to demonstrate the spectral accuracy attainable. Although a simple Laplace problem is examined, the analysis covers more complex and general cases.
Drug-related problems in hospitals: a review of the recent literature.
Krähenbühl-Melcher, Anita; Schlienger, Raymond; Lampert, Markus; Haschke, Manuel; Drewe, Jürgen; Krähenbühl, Stephan
2007-01-01
Problems associated with pharmacotherapy (in particular, medication errors and adverse drug events) are frequent and are associated with increased costs for treatment. Analysis of original publications published between 1990 and 2005 on the topics of medication errors and/or adverse drug events in hospitalised patients, focusing on the frequency of, risk factors for and avoidance of such problems associated with pharmacotherapy, indicated that medication errors occurred in a mean of 5.7% of all episodes of drug administration, but with a high variability among the 35 studies retrieved. This variability was explained by the methods by which medication errors were detected (systematic screening of patients versus chart review or spontaneous reporting) and by the way drugs were administered (intravenously administered drugs are associated with the highest error frequencies). Errors occurred throughout the whole medication process, with administration errors accounting for more than half of all errors. Important risk factors included insufficient pharmacological knowledge of health professionals, errors in the patient charts or documentation by nurses and inadequate pharmacy services.Adverse events or reactions, on the other hand, affected 6.1 patients per 100 hospitalised and also showed a high variability among the 46 studies retrieved. This variability could also be explained by the different methods of assessment of the frequency of adverse drug events or reactions, as well as by the different wards on which the studies were performed. Important risk factors for adverse drug events or reactions included polypharmacy, female sex, drugs with a narrow therapeutic range, renal elimination of drugs, age >65 years and use of anticoagulants or diuretics. Since medication errors are strong risk factors for preventable adverse drug events or reactions, strategies have to be put in place for their reduction. Such strategies include ensuring that all persons involved in the
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.
Novel apparatus and method for drug reinforcement.
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
Projection methods: Results and open problems
Bauschke, H.
1994-12-31
The convex feasibility problem consists of finding a point in the intersection of convex constraint sets. It is very easy to state and has an immediate geometric appeal; its real significance, however, lies in the wide range of applications in mathematics and physical sciences. The method of cyclic projections is an iterative attempt to solve the convex feasibility problem: a convergent sequence is generated by projecting cyclically onto the constraint sets and its limit is a solution. This and similar other methods have been used in practice with great success and quite a few theoretical results are known. Nonetheless, some fundamental questions remain open! In this talk, I will present some (of my favorite) open problems and what`s known about them.
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...
a Numerical Method for Turbulent Combustion Problems
NASA Astrophysics Data System (ADS)
Song, Yu.
This dissertation presents a random numerical method which combines a random vortex method and a random choice method. With the assumption of incompressibility, the equations governing the fluid motion can be uncoupled from the equations governing the chemical reaction. A hybrid random vortex method is used for solving Navier -Stokes equation which governs the fluid motion. Combustion process is governed by reaction-diffusion system for the conservation of energy and the various chemical species participating in reaction. A random choice method is used for the modeling reaction-diffusion equations. The random choice method is tested and the numerical solutions are compared with the results by either the other numerical methods or exact solutions, good improvement and agreement have been obtained. For physical problem in two or more space dimensions, extension of the random choice method requires splitting the source terms into an x-sweep followed by a y-sweep. The splitting of the source term is also examined for an equation with an exact solution. The combustion model is applied to the problem of combustion in a circular cylinder with cylinder heated or kept cold. The flame profiles are obtained and effect of the turbulent is observed. The method is also applied to the ignition of a Bunsen burner. The correct modeling of mixing layer at the edge of the burner is found important in this application. Flame propagation profiles are obtained and have good agreement with experiments.
Prevalence of skin problems and leg ulceration in a sample of young injecting drug users
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
Transport Test Problems for Hybrid Methods Development
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.
Adjoint variational methods in nonconservative stability problems.
NASA Technical Reports Server (NTRS)
Prasad, S. N.; Herrmann, G.
1972-01-01
A general nonself-adjoint eigenvalue problem is examined and it is shown that the commonly employed approximate methods, such as the Galerkin procedure, the method of weighted residuals and the least square technique lack variational descriptions. When used in their previously known forms they do not yield stationary eigenvalues and eigenfunctions. With the help of an adjoint system, however, several analogous variational descriptions may be developed and it is shown in the present study that by properly restating the method of least squares, stationary eigenvalues may be obtained. Several properties of the adjoint eigenvalue problem, known only for a restricted group, are shown to exist for the more general class selected for study.
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
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.
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
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…
An inverse problem by boundary element method
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.
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…
The Problem of Confounding in Studies of the Effect of Maternal Drug Use on Pregnancy Outcome
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
Drug susceptibility testing by dilution methods.
Jeannot, Katy; Plésiat, Patrick
2014-01-01
Serial twofold dilution methods are widely used to assess the bacteriostatic activities of antibiotics. This can be achieved by dilution of considered drugs in agar medium or in culture broth, and inoculation by calibrated inoculums. Although seemingly simple, these methods are greatly influenced by the experimental conditions used and may lead to discrepant results, in particular with untrained investigators. The present step-by-step protocol has been validated for Pseudomonas species, including P. aeruginosa. Introduction of appropriate control strains is crucial to ascertain minimal inhibitory concentration values and compare the results of independent experiments.
Alcohol and Drugs in Schools: Teachers' Reactions to the Problem
ERIC Educational Resources Information Center
Finn, Kristin V.; Willert, H. Jeannette
2006-01-01
Although schools are places for learning and growth, they are also places where students engage in alcohol and drug use. This study showed that most teachers were aware of drugs in their schools, but did not regard drug use as an interference in their own classrooms. Many teachers were knowledgeable about their schools' drug policy, but did not…
A meshless method for unbounded acoustic problems.
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.
A meshless method for unbounded acoustic problems.
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
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
Protective Factors Can Mitigate Behavior Problems After Prenatal Cocaine and Other Drug Exposures
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
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.
Kinetics methods for clinical epidemiology problems
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
Kinetics methods for clinical epidemiology problems.
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.
Problems and Solutions in Click Chemistry Applied to Drug Probes
Zhong, Weilong; Sun, Bo; Lu, Cheng; Yu, Hengheng; Wang, Changhua; He, Lingfei; Gu, Ju; Chen, Shuang; Liu, Yanrong; Jing, Xiangyan; Bi, Zhun; Yang, Guang; Zhou, Honggang; Sun, Tao; Yang, Cheng
2016-01-01
Small-molecule fluorescent probes have been widely used in target identification, but this method has many disadvantages. For example, the identified proteins are usually complex, and additional biochemical studies are needed to distinguish real targets from interference results. To address this problem, we propose a series of strategies for improving the efficiency of target identification. First, pretreatment with a lower concentration of hydrogen peroxide can shield against thiol interference. Second, the use of benzophenone as a photo-affinity group is not appropriate, and diazirines are preferred. Third, if cytoskeleton proteins or stress proteins are captured, the interference must be carefully eliminated. The specificity of target identification can be improved by optimizing these three strategies. In this paper, we discuss the problems associated with the use of the click reaction in living cells and provide important complementary techniques for photo-affinity probes based on the click chemistry reaction. PMID:27782133
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)
Drug-related problems in type 2 diabetes mellitus patients with dyslipidemia
2013-01-01
Background Drug-Related Problems (DRPs) commonly occur among type 2 diabetes mellitus (T2DM) patients. However, few studies have been performed on T2DM patients with dyslipidemia. This purpose of this study was to assess drug-related problems (DRPs) and factors associated with its occurrence. Methods The retrospective study involved 208 T2DM in-patients and out-patients with dyslipidemia, and was conducted at a tertiary hospital in Malaysia from January 2009 to December 2011. The identification and assessment of DRPs were based on the Pharmaceutical Care Network Europe (PCNE) tool version 5.01. The potentially inappropriate medication use in older adults was assessed based on the American Geriatrics Society updated Beers Criteria. Results A total of 406 DRPs were identified. Among these patients, 91.8% had at least one DRP, averaging 1.94 ± 1.10 problems per patient. The majority of T2DM patients with dyslipidemia (91.8%) had at least one DRP. The most frequent types of DRP were potential drug-drug interaction (18.0%), drug not taken or administered (14.3%) and insufficient awareness of health and diseases (11.8%). Anti-hypertensive, lipid-modifying and anti-diabetic agents were the drug classes that were most likely to be associated with DRPs. Male gender, renal impairment, polypharmacy and poor lipid control were factors that were significantly associated with DRP in diabetic dyslipidemia patients. Conclusion Early identification of DRPs and factors associated with them are essential to prevent and resolve DRPs in T2DM patients with dyslipidemia. PMID:24341672
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…
Drug use, mental health and problems related to crime and violence: cross-sectional study1
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
Immersed interface methods for moving interface problems
NASA Astrophysics Data System (ADS)
Li, Zhilin
1997-05-01
A second order difference method is developed for the nonlinear moving interface problem of the form u_t + λ uu_x = ( {β u_x } )_x - f( {x,t} ),x in [ {0,α } ) \\cup ( {α ,1} ]} }. {d}{α}/{dt} = w( {t,α ;u,u_x } ), , where α (t) is the moving interface. The coefficient β(x,t) and the source term f(x,t) can be discontinuous across α (t) and moreover, f(x,t) may have a delta or/and delta-prime function singularity there. As a result, although the equation is parabolic, the solution u and its derivatives may be discontinuous across α (t). Two typical interface conditions are considered. One condition occurs in Stefan-like problems in which the solution is known on the interface. A new stable interpolation strategy is proposed. The other type occurs in a one-dimensional model of Peskin's immersed boundary method in which only jump conditions are given across the interface. The Crank-Nicolson difference scheme with modifications near the interface is used to solve for the solution u(x,t) and the interface α (t) simultaneously. Several numerical examples, including models of ice-melting and glaciation, are presented. Second order accuracy on uniform grids is confirmed both for the solution and the position of the interface.
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
Methods for testing impairment of driving due to drugs.
Irving, A; Jones, W
1992-01-01
The Transport and Road Research Laboratory has been concerned for a long time with possible causes of driving difficulties and has developed methods for investigating driving performance. The question addressed here was how applicable these methods are in assessing driving problems arising from the use of drugs which can impair performance, particularly widely-available centrally-acting drugs. We assessed four types of driving-related tests by comparing their sensitivities with two laboratory tests, developed elsewhere, which measure more basic effects of drugs on performance, using drugs known to impair skills. Performances under the influences of ethanol, the benzodiazepine lorazepam, and the antihistamine triprolidine, each given both as a single high dose and a single low dose, were compared with performances after placebo. We used double-blind crossover design, in which subject variability was minimized by studying only women of a limited age range (45-55 y). The driving-related tests detected the effects of the substances used, although they were generally less sensitive than the laboratory tests. The individual sensitivities of the driving test could be improved to match those used for more general assessments.
MIB Galerkin method for elliptic interface problems.
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
MIB Galerkin method for elliptic interface problems
Xia, Kelin; Zhan, Meng; Wei, Guo-Wei
2014-01-01
Summary 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
[Discussion on polysaccharide determination methods in new Chinese drug research].
Li, Ji-Ping
2014-09-01
According to existing problems in polysaccharide determination methods in new Chinese drug applications, the method suitability, chemical reference selection, components interference and method research were introduced. The author suggests that suitable determination method should be selected according to the structure and property of the polysaccharide, and validated. Some influent factors should be examined to assure the accuracy of the method, such as the stability and using amount of the visualizing reagent, visualizing time, maximum detection wavelength etc. Monosaccharide and other water soluble components should be removed from polysaccharide sample, and suitable reference substance and detection wavelength should be selected. It should pay attention to mutual interference of neutral and acidic saccharide, and use inhibitor to eliminate the interference. Because the slopes of the standard curves are different for different monosaccharide, it is proposed that the types and ratios of the monosaccharide in heteroglycan should be understood, and mixed reference substance solution in the ratio is prepared for determination. PMID:25522636
[Study methods of drugs in Alzheimer disease].
Dubois, B; Stehlé, B; Lehner, J P; Derouesné, C; Bourin, M; Lamour, Y; Blin, O; Jourdain, G; Alperovitch, A
1996-01-01
The availability of new drugs for Alzheimer's disease, with different pharmacological profiles, leads to a redefinition the relevant methodology for developing drugs in this indication, including the inclusion/exclusion criteria, the duration of the studies, and therefore, the relevant guidelines. This was the purpose of the Giens Round-table devoted to the new methodology for drug development in Alzheimer disease.
Problems of applicability of statistical methods in cosmology
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.
Developing natural product drugs: Supply problems and how they have been overcome.
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
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…
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)
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…
[The therapeutic problem of current drug addiction in Italy].
De Caro, D
1980-04-28
Psicosocial factors which are of main importance for drug-dependences, especially in young people, are examined. Then the most important elements of the therapy of drug-dependences are indicated, which first of all consists in the necessary treatment in the hospital and farmacological therapy (particularly during acute and over-dose states), and also psicotherapeutic--generally speaking--and social approaches. Among those therapeutic Communities seem to be extremely significant, whose most important patterns are described.
Currie, Cheryl L; Wild, T Cameron; Schopflocher, Donald P; Laing, Lory; Veugelers, Paul
2013-07-01
Illicit and prescription drug use disorders are two to four times more prevalent among Aboriginal peoples in North America than the general population. Research suggests Aboriginal cultural participation may be protective against substance use problems in rural and remote Aboriginal communities. As Aboriginal peoples continue to urbanize rapidly around the globe, the role traditional Aboriginal beliefs and practices may play in reducing or even preventing substance use problems in cities is becoming increasingly relevant, and is the focus of the present study. Mainstream acculturation was also examined. Data were collected via in-person surveys with a community-based sample of Aboriginal adults living in a mid-sized city in western Canada (N = 381) in 2010. Associations were analysed using two sets of bootstrapped linear regression models adjusted for confounders with continuous illicit and prescription drug problem scores as outcomes. Psychological mechanisms that may explain why traditional culture is protective for Aboriginal peoples were examined using the cross-products of coefficients mediation method. The extent to which culture served as a resilience factor was examined via interaction testing. Results indicate Aboriginal enculturation was a protective factor associated with reduced 12-month illicit drug problems and 12-month prescription drug problems among Aboriginal adults in an urban setting. Increased self-esteem partially explained why cultural participation was protective. Cultural participation also promoted resilience by reducing the effects of high school incompletion on drug problems. In contrast, mainstream acculturation was not associated with illicit drug problems and served as a risk factor for prescription drug problems in this urban sample. Findings encourage the growth of programs and services that support Aboriginal peoples who strive to maintain their cultural traditions within cities, and further studies that examine how Aboriginal
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...
Who's to Blame for America's Drug Problem?: The Search for Scapegoats in the "War on Drugs."
ERIC Educational Resources Information Center
Mackey-Kallis, Susan; Hahn, Dan
1994-01-01
Analyzes six years (from 1986 to 1991) of political debate and social action in the United States' war on drugs. Explores the characteristics of guilt-based, scapegoating drug rhetoric and how scapegoating in the drug war has been problematic. Discusses the desirability and limits of guilt as a rhetorical strategy. (HB)
Ending Discrimination against People with Alcohol and Drug Problems.
ERIC Educational Resources Information Center
Join Together, Boston, MA.
People with alcohol or other drug disease face public and private policies that restrict their access to appropriate health care, employment, and public benefits, discouraging them from seeking treatment, robbing them of hope for recovery, and costing society millions of dollars. Join Together, a project of Boston University School of Public…
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)
[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…
De Brouwere, V; Van Lerberghe, W; Criel, B; Van Dormael, M
1996-01-01
A Primary Health Care (PHC) system may be effective and efficient to the extent that essential drugs are available in health services and financially accessible to the population. In developing countries, besides the difficulties related to supplying health services with adequate amounts of drugs, the control of drug consumption is one of the frequent problems encountered by health authorities. Literature is relatively abundant in the field of rationalization of the diagnosis and drug prescription processes, and also in the field of drug financing mechanisms; publications are however rather scarce when topics related to corruption or drug misappropriation are concerned. The case study submitted hereafter reports a drug overconsumption problem in the health centres (HC) of the Kasongo district (Zaire). Despite the existence of direct control mechanisms as well as indirect ones (monitoring of drug consumption by HC), the problem has been identified belatedly. The district staff then used a step-by-step analysis of the HC drug consumption profiles; this analysis allowed to demonstrate that misappropriation would be the most plausible hypothesis. In order to solve the misappropriation problem-the consequences of which jeopardized the functioning of the very health system-the district staff chose to involve the nurses, in charge of the HC, in the entire problem-solving process. This participative approach, involving different actors as partners, allowed to deepen the situation analysis and to elaborate solutions congruent with PHC principles and acceptable to all concerned.
Brunelle, Natacha; Bertrand, Karine; Beaudoin, Isabelle; Ledoux, Cinthia; Gendron, Annie; Arseneault, Catherine
2013-08-01
Previous research has documented associations of addiction with delinquency and psychological problems. However, few studies have evaluated their influence on adolescent's drug use trajectories. The current study aims to examine the influence of these factors on the recovery trajectories of 199 youths aged 15.6 years on average admitted to inpatient and outpatient addiction treatment centers, followed up three and six months later. Results indicate that youth who show higher severity of drug abuse exhibit greater improvement than youth with a lower severity of drug abuse at the onset of treatment. Although psychological problems were associated with baseline drug use, they did not influence drug use trajectory over time. Only delinquency influenced the recovery trajectories of these youth. Results suggest that a high level of delinquency can have a significant effect on the drug recovery process of adolescents and that interventions should attempt to reduce both drug use and delinquency.
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…
Discontinuous mixed covolume methods for parabolic problems.
Zhu, Ailing; Jiang, Ziwen
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 L(2).
Computational Methods Applied to Rational Drug Design
Ramírez, David
2016-01-01
Due to the synergic relationship between medical chemistry, bioinformatics and molecular simulation, the development of new accurate computational tools for small molecules drug design has been rising over the last years. The main result is the increased number of publications where computational techniques such as molecular docking, de novo design as well as virtual screening have been used to estimate the binding mode, site and energy of novel small molecules. In this work I review some tools, which enable the study of biological systems at the atomistic level, providing relevant information and thereby, enhancing the process of rational drug design. PMID:27708723
Problems for rheumatic patients in opening dispensed drug containers.
Lisberg, R B; Higham, C; Jayson, M I
1983-05-01
The ability of 50 rheumatoid arthritis patients with hand involvement and 50 normal control subjects to open a range of reclosable tablet containers and unit dose packs was tested. Child-resistant containers, particularly the clic-loc type, proved the most difficult for patients and control subjects to open. Smaller containers were less easy to open than comparable ones of a larger size. Only 54% patients were able to remove a suppository from its wrapping. Blister packs and conventional screw-capped tablet bottles were easiest to open. Dispensing of drugs for rheumatic patients in child-resistant containers should be limited to those without hand involvement. PMID:6850197
Role of Molecular Dynamics and Related Methods in Drug Discovery.
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
Preconditioned Krylov subspace methods for eigenvalue problems
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.
IOSIE: A Method for Analyzing Student Behavioral Problems
ERIC Educational Resources Information Center
Scarpaci, Richard T.
2007-01-01
The author argues for a rational method to analyze behavior problems and proposes a method of identifying the problem, the objectives to be achieved, the solution, the implementation, and the evaluation (IOSIE) as a practical approach to assist teachers in resolving most classroom behavior management problems. The approach draws heavily on…
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…
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…
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…
Lessons from the Field: Profiling State Alcohol, Tobacco & Other Drug Problems.
ERIC Educational Resources Information Center
Drug Strategies, Washington, DC.
This document is a step-by-step guide to profiling statewide alcohol, tobacco, and other drug problems and policies. Profiles of this sort capture the complexity of alcohol, tobacco, and other drug abuse indicators at the local level, incorporating data from a range of disciplines and making it possible to design data-driven interventions. The…
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.
Stable isotope method to measure drug release from nanomedicines.
Skoczen, Sarah; McNeil, Scott E; Stern, Stephan T
2015-12-28
Existing methods to measure nanomedicine drug release in biological matrices are inadequate. A novel drug release method utilizing a stable isotope tracer has been developed. Stable isotope-labeled drug is spiked into plasma containing nanomedicine. The labeled drug equilibrates with plasma components identical to the normoisotopic drug released from the nanomedicine formulation. Therefore, the ultrafilterable fraction of the isotope-labeled drug represents a reliable measure of free normoisotopic drug fraction in plasma, and can be used to calculate nanomedicine encapsulated and unencapsulated drug fractions. To demonstrate the utility of this method, we performed a plasma drug release study with both a fast releasing commercial docetaxel formulation, Taxotere®, and a delayed releasing nanomicellar formulation of a docetaxel prodrug, Procet 8. The instability of the unencapsulated prodrug in plasma allowed us to compare our calculated prodrug release and docetaxel conversion with the actual docetaxel concentration measured directly without fractionation. Drug release estimates for the fast releasing Taxotere formulation demonstrated accuracy deviation and precision (%CV) of <15%. For the controlled release Procet 8 formulation, we calculated a slow release and conversion of the prodrug in rat plasma that was highly correlated with the direct docetaxel measurement (R(2)=0.98). We believe that this method will have tremendous utility in the development and regulatory evaluation of nanomedicines, and aid in determination of generic bioequivalence.
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
[Identifying and solving drug-related problems in terms of the community pharmacist].
Masaryková, Lucia; Fulmeková, Magdaléna; Lehocká, Lubica; Fazekaš, Tomáš
2014-02-01
The issue of drug related problems (DRPs) has been known and dealt with in many studies for a long time. It is primarily due to the fact that drug-related problems have the potential to increase patients morbidity and mortality in particular. The issue of identifying and solving drug-related problems in the area of pharmacotherapy by community pharmacists in the Slovak Republic, unlike in other European countries such as the Netherlands and the United Kingdom, is still at the beginning and gradually developing. The aim of the survey was to obtain information from pharmacy practice concerning the current state and possible solutions of potential risks of medicines in the form of drug-related problems of patients from community pharmacists point of view as well as to find out the role and status of community pharmacists in identifying and solving drug-related problems. A questionnaire survey using a sample of 237 respondents, its statistical processing and evaluation revealed the drug-related problems frequency met at their patients (the most common types of DRPs, their causes and subsequent intervention), as well as the opinions of community pharmacists on their current possibilities of (legislative, material, personnel, time) solving and risk-rating therapies for patients.
An Approximate Matching Method for Clinical Drug Names
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
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.
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.
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…
Homogenization method based on the inverse problem
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)
A Computer Assisted Problem Solving Method for Beginning Chemistry Students.
ERIC Educational Resources Information Center
Powers, Michael H.
1984-01-01
Outlines a problem-solving method for beginning chemistry students that utilizes specific, concrete steps as well as computer-assisted tutorials. The method involves an approach referred to as the Factor-Unit Method coupled with a graphical "road map" which allows students to trace problems from start to finish. (JN)
Why So Few Drugs for Alzheimer's Disease? Are Methods Failing Drugs?
Becker, Robert E.; Greig, Nigel H.
2010-01-01
Recent studies of Alzheimer's disease (AD) and other neuropsychiatric drug developments raise questions whether failures of some drugs occur due to flaws in methods. In three case studies of recent AD drug development failures with phenserine, metrifonate, and tarenflurbil we identified methodological lapses able to account for the failures. Errors in complex systems such as drug developments are both almost inescapable due to human mistakes and most frequently hidden at the time of occurrence and thereafter. We propose preemptive error management as a preventive strategy to exclude or control error intrusions into neuropsychiatric drug developments. We illustrate the functions we anticipate for a preemptive error management preventive strategy with a checklist and identify the limitations of this aspect of the proposal with three drug examples. This strategy applies core scientific practices to insure the quality of data within the current context of AD drug development practices. PMID:20704560
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.
Commentary on "Alzheimer's Disease Drug Development and the Problem of the Blood-Brain Barrier".
Simpkins, James W
2009-09-01
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 beta-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
ERIC Educational Resources Information Center
Hurst, Hunter, Ed.; And Others
1984-01-01
This document contains the third volume of "Today's Delinquent," an annual publication of the National Center for Juvenile Justice. This volume deals with the issue of drugs and includes articles by leading authorities in delinquency and substance abuse who share their views on causes and cures for the drug problem among youth in this country.…
Access to generic drugs in the 1950s: the politics of a social problem.
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
Boundary integral methods for microfluidic problems
NASA Astrophysics Data System (ADS)
Burbidge, Adam
2015-01-01
Microscale experiments of reduced complexity allow one to tease out and examine some of the interesting phenomena that manifest in large hierarchically structured materials which are of general interest across many industries. Recent advances in high speed imaging techniques and post-processing allow experiments to yield small scale information which was previously unavailable, or extremely difficult to obtain. This additional information provides new challenges in terms of theoretical understanding and prediction that requires new tools. We discuss generalised weighted residual numerical methods as a means of solving physically derived systems of PDEs, using the steady Stokes equation as an example. These formulations require integration of arbitrary functions of submanifolds which often will have a lower dimensionality than the parent manifold, leading to cumbersome calculations of the Jacobian determinant. We provide a tensorial view of the transformation, in which the natural element coordinate system is a non-orthogonal frame, and derive an expression for the Jacobian factor in terms of the contravariant metric tensor gij. This approach has the additional advantage that it can be extended to yield the local surface curvature, which will be essential for correct implementation of free surface boundaries.
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…
Methods to Design and Synthesize Antibody-Drug Conjugates (ADCs)
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
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.
A Modified Alternating Direction Method for Variational Inequality Problems
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.
On the spectral methods for population balance problems
NASA Astrophysics Data System (ADS)
Solsvik, J.; Jakobsen, H. A.
2013-10-01
Numerical methods in the weighted residual framework have been evaluated for three population balance (PB) problems. Based on the present solution results, the orthogonal collocation method is recommended above the tau and least-squares methods. The orthogonal collocation method holds the simplest algebra theory, obtains high accuracy, and is more computational efficient compared to the other methods evaluated.
Methodological aspects of current problems in target-based anticancer drug development.
Yamanaka, Takeharu; Okamoto, Tatsuro; Ichinose, Yukito; Oda, Shinya; Maehara, Yoshihiko
2006-06-01
Differently from the conventional antineoplastic agents, target-based drugs are designed a priori, based on our knowledge of various physiological molecules that has been obtained by the development of molecular biology. This "Copernican revolution" in drug development may imply a paradigm shift in this field. However, contrary to the initial expectations, many drugs developed by this approach are now faced with difficulties, mainly because of the fundamental and theoretical limits of this approach. All of the physiological functions are not always known in all target molecules. In low-molecular-weight drugs, i.e., "inhibitors," targets disperse, due to the structural similarities in physiological molecules. This double-faced "out-of-focusing" causes many problems in various steps of drug development, drug design, clinical trials, and administration to patients. Many drugs are now being abandoned because of unexpectedly lower response rates or unforeseeable adverse effects, and the variety of the drugs exhibits a kaleidoscopic appearance. The double-faced "out-of-focusing" derives from the methodological limits in molecular biology, i.e., elementalism, and limits in our techniques for drug development. To overcome these currently inevitable limits, it appears essential to elucidate the specific changes in target molecules that chiefly promote tumor growth and, consequently, strongly predict response to the administered drugs. Precise and efficient detection of responder populations is the key to the development and establishment of target-based anticancer therapies. PMID:16850122
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.
Multiplier methods for optimization problems with Lipschitzian derivatives
NASA Astrophysics Data System (ADS)
Izmailov, A. F.; Kurennoy, A. S.
2012-12-01
Optimization problems for which the objective function and the constraints have locally Lipschitzian derivatives but are not assumed to be twice differentiable are examined. For such problems, analyses of the local convergence and the convergence rate of the multiplier (or the augmented Lagrangian) method and the linearly constraint Lagrangian method are given.
Child abuse, drug addiction and mental health problems of incarcerated women in Israel.
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.
Data sources and methods for ascertaining human exposure to drugs.
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
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.
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
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.
Application of the hybrid method to inverse heat conduction problems
NASA Astrophysics Data System (ADS)
Chen, Han-Taw; Chang, Shiuh-Ming
1990-04-01
The hybrid method involving the combined use of Laplace transform method and the FEM method is considerably powerful for solving one-dimensional linear heat conduction problems. In the present method, the time-dependent terms are removed from the problem using the Laplace transform method, and then the FEM is applied to the space domain. The transformed temperature is inverted numerically to obtain the result in the physical quantity. The estimation of the surface heat flux or temperature from transient measured temperatures inside the solid agrees well with the analytical solution of the direct problem without Beck's sensitivity analysis and a least-square criterion. Due to no time step, the present method can directly calculate the surface conditions of an inverse problem without step by step computation in the time domain until the specific time is reached.
A Novel Drug-Mouse Phenotypic Similarity Method Detects Molecular Determinants of Drug Effects
Prinz, Jeanette; Vogt, Ingo; Adornetto, Gianluca; Campillos, Mónica
2016-01-01
The molecular mechanisms that translate drug treatment into beneficial and unwanted effects are largely unknown. We present here a novel approach to detect gene-drug and gene-side effect associations based on the phenotypic similarity of drugs and single gene perturbations in mice that account for the polypharmacological property of drugs. We scored the phenotypic similarity of human side effect profiles of 1,667 small molecules and biologicals to profiles of phenotypic traits of 5,384 mouse genes. The benchmarking with known relationships revealed a strong enrichment of physical and indirect drug-target connections, causative drug target-side effect links as well as gene-drug links involved in pharmacogenetic associations among phenotypically similar gene-drug pairs. The validation by in vitro assays and the experimental verification of an unknown connection between oxandrolone and prokineticin receptor 2 reinforces the ability of this method to provide new molecular insights underlying drug treatment. Thus, this approach may aid in the proposal of novel and personalized treatments. PMID:27673331
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 unless they are corrected? 40.203 Section 40.203 Transportation Office of the Secretary of Transportation PROCEDURES FOR TRANSPORTATION WORKPLACE DRUG AND ALCOHOL TESTING PROGRAMS Problems in Drug Tests §...
Elliptic interface problem solved using the mixed finite element method
NASA Astrophysics Data System (ADS)
Wang, Shuqiang
2007-05-01
The elliptic boundary value/interface problem is very important in many applications, for example, in incompressible flow and MHD. Many methods are used to solve these problems in a complex domain, including the finite volume method, the finite element method and the boundary element method. For a complex computational domain, the better choice of the partition of the computational domain is to use an unstructured grid. However, it is not a straight forward task to implement a mesh generation program. Such a program requires extra computing time and resources (such as computer memory). Thus people like to use a structured mesh if possible, especially a cartesian mesh. Popular methods using structured cartesian grids for the elliptic boundary value/interface problem include the immersed boundary method, the immersed interface method, the ghost fluid method, and the embedded boundary method. This thesis solves the elliptic problem using several versions of the mixed nite element method on an unstructured mesh. The results are compared for speed and accuracy to the embedded boundary method. A ghost fluid method for elliptic boundary value/interface problems is also investigated. Finally, a simple test of the 2D Rayleigh-Taylor instability is performed using the FronTier-Lite package. Key Words. Elliptic Boundary Value, Interface, Mesh Generation, Quadtree, Octree, Front Tracking.
Methods for solving ill-posed inverse problems
NASA Astrophysics Data System (ADS)
Alifanov, O. M.
1983-11-01
Various approaches to the solution of inverse problems of heat conduction are reviewed, including direct analytical and numerical methods, the method of iterative regularization, and algebraic and numerical methods regularized in accordance with the variational principle. The method of iterative regularization is shown to be the most versatile of the above approaches. The basic principles of this method are briefly examined, and methods are proposed for computing the gradients of discrepancies. An approach is proposed to the iterative solution of inverse problems with a specified order of smoothness.
Are therapeutic vaccines an answer to the global problem of drug and alcohol abuse?
Brashier, Dick B. S.; Sharma, Ashok Kumar; Akhoon, Neha
2016-01-01
Drug Abuse has become a major challenging problem for the society. It effects people of all countries economical strata's and all ages. According. Monetary loss all over the world regarding drug abuse is in million dollars, it not only has an impact on human productivity and healthcare cost but also on cost of crimes conducted by these drugs and alcohol abuse. Therapeutic vaccine has come as new approach to deal with this problem, after failures in search for a pharmaceutical agent to deal with drug of abuse and alcohol. Research in field of nicotine abuse has gone a way ahead with number of vaccines being tried clinically followed by cocaine, opioids, methamphetamine, phencyclidine and alcohol. All of them have a common mechanism of action by antibody production whereas alcohol acts by genetic intervention. None have being approved yet due to poor results in phase II trials, possibly due to not able to trigger an adequate immunological response. But still quest is on for cracking the ice by developing first successful vaccine against drug of abuse, that would follow for other drugs too. It would be great step in field of therapeutic vaccines for drug abuse after similar successful vaccines being approved for other diseases like cancer. PMID:27721531
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.
On 2D bisection method for double eigenvalue problems
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.
Newton's method for large bound-constrained optimization problems.
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.
Schwarz alternating methods for anisotropic problems with prolate spheroid boundaries.
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
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.
In silico methods for drug repurposing and pharmacology.
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
In silico methods for drug repurposing and pharmacology.
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.
An accurate method for two-point boundary value problems
NASA Technical Reports Server (NTRS)
Walker, J. D. A.; Weigand, G. G.
1979-01-01
A second-order method for solving two-point boundary value problems on a uniform mesh is presented where the local truncation error is obtained for use with the deferred correction process. In this simple finite difference method the tridiagonal nature of the classical method is preserved but the magnitude of each term in the truncation error is reduced by a factor of two. The method is applied to a number of linear and nonlinear problems and it is shown to produce more accurate results than either the classical method or the technique proposed by Keller (1969).
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.
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
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…
ERIC Educational Resources Information Center
Szapocznik, Jose; And Others
1989-01-01
Studies efficacy of Family Effectiveness Training (FET), a prevention and intervention model used with Hispanic families of preadolescents at risk of drug abuse. Studies 79 Hispanic families assigned to FET or control group. FET families showed greater improvement in structural family functioning, reported problem behaviors, and child…
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.
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.
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.
Spectral finite-element methods for parametric constrained optimization problems.
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.
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.
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.
Domain decomposition methods for solving an image problem
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.
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.
Postmortem Presence of Drugs and Method of Violent Suicide
Sheehan, Connor M.; Rogers, Richard G.; Boardman, Jason D.
2016-01-01
The link between substance use and suicide is well established. However, little research analyzes how substance use is related to the method of suicide. This paper analyzes how specific drugs are associated with method of suicide, a critical topic because drug use bears on the etiology of suicide and may lead to policies aimed at deterring suicide. We use the COVDRS and logistic regression to examine postmortem presence of drugs among 3,389 hanging and firearm suicides in Colorado from 2004–2009. Net of demographic controls, we find that opiates are positively associated with firearms (OR: 1.92, 95% L: 1.27, 95% U: 2.86]) while antidepressants are positively associated with hanging (OR: 1.45, 95% L: 1.04, 95% U: 2.03). For cocaine and opiates, the association between drug use and violent method vary by educational attainment. Importantly, knowledge of the presence and type of specific drug is strongly associated with the method of suicide. PMID:27239069
[Applications of the Fragment Molecular Orbital Method in Drug Discovery].
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
Clinical pragmatism: a method of moral problem solving.
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.
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…
[The problem of post-marketing surveillance planning on drugs for infectious disease].
Sato, J
2001-12-01
In principle, a new drug is approved via the assessments of safety and efficacy by the Ministry of Health, Labor and Welfare (MHLW). After approval, conduct of post-marketing surveillance is requested by law in order to assess the safety and efficacy of the drug in a large number of patients. Before initiating a surveillance, submission to MHLW of a document on the plan of survey is necessary in the purpose of inspection if it includes any ethical or regulatory problem or not. Through the inspections of the plans submitted during the period of April 1998 and March 2000, many problems have been pointed out. In this report, the author introduces some of the concrete problems noted in the plans on drugs for infectious diseases and shows some of the guidance made by the authority how to improve them. It is expected that such practical analyses of cases may be useful for future planning of post-marketing surveillance on drugs for infectious diseases.
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.
Error Analysis for Discontinuous Galerkin Method for Parabolic Problems
NASA Technical Reports Server (NTRS)
Kaneko, Hideaki
2004-01-01
In the proposal, the following three objectives are stated: (1) A p-version of the discontinuous Galerkin method for a one dimensional parabolic problem will be established. It should be recalled that the h-version in space was used for the discontinuous Galerkin method. An a priori error estimate as well as a posteriori estimate of this p-finite element discontinuous Galerkin method will be given. (2) The parameter alpha that describes the behavior double vertical line u(sub t)(t) double vertical line 2 was computed exactly. This was made feasible because of the explicitly specified initial condition. For practical heat transfer problems, the initial condition may have to be approximated. Also, if the parabolic problem is proposed on a multi-dimensional region, the parameter alpha, for most cases, would be difficult to compute exactly even in the case that the initial condition is known exactly. The second objective of this proposed research is to establish a method to estimate this parameter. This will be done by computing two discontinuous Galerkin approximate solutions at two different time steps starting from the initial time and use them to derive alpha. (3) The third objective is to consider the heat transfer problem over a two dimensional thin plate. The technique developed by Vogelius and Babuska will be used to establish a discontinuous Galerkin method in which the p-element will be used for through thickness approximation. This h-p finite element approach, that results in a dimensional reduction method, was used for elliptic problems, but the application appears new for the parabolic problem. The dimension reduction method will be discussed together with the time discretization method.
TWO-GRID METHODS FOR MAXWELL EIGENVALUE PROBLEMS
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
Methods for solving of inverse heat conduction problems
NASA Astrophysics Data System (ADS)
Kobilskaya, E.; Lyashenko, V.
2016-10-01
A general mathematical model of the high-temperature thermodiffusion that occurs in a limited environment is considered. Based on this model a formulation of inverse problems for homogeneous and inhomogeneous parabolic equations is proposed. The inverse problem aims at identifying one or several unknown parameters of the mathematical model. These parameters allow maintaining the required temperature distribution and concentration of distribution of substance in the whole area or in part. For each case (internal, external heat source or a combination) the appropriate method for solving the inverse problem is proposed.
Iterative methods for solving nonlinear problems of nuclear reactor criticality
Kuz'min, A. M.
2012-12-15
The paper presents iterative methods for calculating the neutron flux distribution in nonlinear problems of nuclear reactor criticality. Algorithms for solving equations for variations in the neutron flux are considered. Convergence of the iterative processes is studied for two nonlinear problems in which macroscopic interaction cross sections are functionals of the spatial neutron distribution. In the first problem, the neutron flux distribution depends on the water coolant density, and in the second one, it depends on the fuel temperature. Simple relationships connecting the vapor content and the temperature with the neutron flux are used.
Solving inverse problems of identification type by optimal control methods
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.
Analytical methods for physicochemical characterization of antibody drug conjugates
Wakankar, Aditya; Chen, Yan; Gokarn, Yatin
2011-01-01
Antibody-drug conjugates (ADCs), produced through the chemical linkage of a potent small molecule cytotoxin (drug) to a monoclonal antibody, have more complex and heterogeneous structures than the corresponding antibodies. This review describes the analytical methods that have been used in their physicochemical characterization. The selection of the most appropriate methods for a specific ADC is heavily dependent on the properties of the linker, the drug and the choice of attachment sites (lysines, inter-chain cysteines, Fc glycans). Improvements in analytical techniques such as protein mass spectrometry and capillary electrophoresis have significantly increased the quality of information that can be obtained for use in product and process characterization and for routine lot release and stability testing. PMID:21441786
The Use of Qsar and Computational Methods in Drug Design
NASA Astrophysics Data System (ADS)
Bajot, Fania
The application of quantitative structure-activity relationships (QSARs) has significantly impacted the paradigm of drug discovery. Following the successful utilization of linear solvation free-energy relationships (LSERs), numerous 2D- and 3D-QSAR methods have been developed, most of them based on descriptors for hydrophobicity, polarizability, ionic interactions, and hydrogen bonding. QSAR models allow for the calculation of physicochemical properties (e.g., lipophilicity), the prediction of biological activity (or toxicity), as well as the evaluation of absorption, distribution, metabolism, and excretion (ADME). In pharmaceutical research, QSAR has a particular interest in the preclinical stages of drug discovery to replace tedious and costly experimentation, to filter large chemical databases, and to select drug candidates. However, to be part of drug discovery and development strategies, QSARs need to meet different criteria (e.g., sufficient predictivity). This chapter describes the foundation of modern QSAR in drug discovery and presents some current challenges and applications for the discovery and optimization of drug candidates
Is There a Space-Based Technology Solution to Problems with Preclinical Drug Toxicity Testing?
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.
Is There a Space-Based Technology Solution to Problems with Preclinical Drug Toxicity Testing?
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
Application of the boundary integral method to immiscible displacement problems
Masukawa, J.; Horne, R.N.
1988-08-01
This paper presents an application of the boundary integral method (BIM) to fluid displacement problems to demonstrate its usefulness in reservoir simulation. A method for solving two-dimensional (2D), piston-like displacement for incompressible fluids with good accuracy has been developed. Several typical example problems with repeated five-spot patterns were solved for various mobility ratios. The solutions were compared with the analytical solutions to demonstrate accuracy. Singularity programming was found to be a major advantage in handling flow in the vicinity of wells. The BIM was found to be an excellent way to solve immiscible displacement problems. Unlike analytic methods, it can accommodate complex boundary shapes and does not suffer from numerical dispersion at the front.
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.
Quantitative Methods in the Study of Drug Use.
ERIC Educational Resources Information Center
Huba, George J.
1983-01-01
Addresses the use of data sources and multivariate data analysis methods for modeling naturally occurring data. Two studies in this special section deal with longitudinal perspectives on drug use and emotional adjustment and an application of log-linear model to examine the stress-buffering function of alcohol. (LLL)
Methods and systems to detect adverse drug reactions in hospitals.
Thürmann, P A
2001-01-01
Detection of adverse drug reactions (ADRs) in hospitals offers the chance to detect serious ADRs resulting in hospitalisation and ADRs occurring in hospitalised patients, i.e. patients with high comorbidity and receiving drugs that are administered only in hospitals. The most commonly applied methods involve stimulated spontaneous reporting of doctors and nurses, comprehensive collection by trained specialists and, more recently, computer-assisted approaches using routine data from hospital information systems. The different methods of ADR detection used result in different rates and types of ADRs and, consequently, in different drug classes being responsible for these ADRs. Another factor influencing the results of surveys is the interpretation of the term ADR, where some authors adhere to the strict definition of the World Health Organization and many others include intended and unintended poisoning as well as errors in prescribing and dispensing, thus referring to adverse drug events. Depending on the method used for screening of patients, a high number of possible ADRs and only few definite ADRs are found, or vice versa. These variations have to be taken into account when comparing the results of further analyses performed with these data. ADR rates and incidences in relation to the number of drugs prescribed or patients exposed have been calculated in only a few surveys and projects, and this interesting pharmacoepidemiological approach deserves further study. In addition, the pharmacoeconomic impact of ADRs, either resulting in hospitalisation or prolonging hospital stay, has been estimated using different approaches. However, a common standardised procedure for such calculations has not yet been defined. Although detection of ADRs in hospitals offers the opportunity to detect severe ADRs of newly approved drugs, these ADRs are still discovered by spontaneous reporting systems. The prospects offered by electronic hospital information systems as well as
In Vivo Methods for the Assessment of Topical Drug Bioavailability
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
Numerical methods on some structured matrix algebra problems
Jessup, E.R.
1996-06-01
This proposal concerned the design, analysis, and implementation of serial and parallel algorithms for certain structured matrix algebra problems. It emphasized large order problems and so focused on methods that can be implemented efficiently on distributed-memory MIMD multiprocessors. Such machines supply the computing power and extensive memory demanded by the large order problems. We proposed to examine three classes of matrix algebra problems: the symmetric and nonsymmetric eigenvalue problems (especially the tridiagonal cases) and the solution of linear systems with specially structured coefficient matrices. As all of these are of practical interest, a major goal of this work was to translate our research in linear algebra into useful tools for use by the computational scientists interested in these and related applications. Thus, in addition to software specific to the linear algebra problems, we proposed to produce a programming paradigm and library to aid in the design and implementation of programs for distributed-memory MIMD computers. We now report on our progress on each of the problems and on the programming tools.
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.
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.
The "rainbow" model: an attempt at a global approach to the drug problem.
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
Emerging Computational Methods for the Rational Discovery of Allosteric Drugs
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
Nanobiological studies on drug design using molecular mechanic method
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
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.
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.
Characterization and Developmental History of Problem Solving Methods in Medicine
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.
Methods for methotrexate determination in macromolecular conjugates drug carrier.
Ciekot, Jarosław; Goszczyński, Tomasz; Boratyńskit, Janusz
2012-01-01
In this paper, two simple, cost-effective and fast methods for quantification of methotrexate (MTX) in the macromolecular conjugates are presented. The method for analysis of total MTX in preparations was based on absorption spectrophotometry. Validation was performed by measuring absorbance at 372 nm of the sodium bicarbonate solution. Curve describing drug concentration against absorption had a linear character in the range of 1.204-40.13 microM. The reproducibility and precision of method was 0.1558 to 3.086%. The recovery of the method was between 99.56 and 104.7%. The limit of quantitation method was 1.050 microM. The method for free MTX determination was based on size exclusion chromatography and UV-VIS detection at the wavelength of 302 nm. Superdex Peptide column (150 x 4.6 mm) and a mobile phase 0.1 M sodium bicarbonate with a flow rate of 0.4 mL/min was used. In the free drug determination method, the curve had a linear character in the range of 2.006-200.6 microM. The reproducibility and precision of method was 0.3761 to 2.452%. The recovery of the method was between 93.18 and 104.5%. The limit of quantitation method was 0.9203 microM. PMID:23285700
Determination of risk factors for drug-related problems: a multidisciplinary triangulation process
Kaufmann, Carole P; Stämpfli, Dominik; Hersberger, Kurt E; Lampert, Markus L
2015-01-01
Introduction and objectives Drug-related problems (DRPs) constitute a frequent safety issue among hospitalised patients leading to patient harm and increased healthcare costs. Because many DRPs are preventable, the specific risk factors that facilitate their occurrence are of considerable interest. The objective of our study was to assess risk factors for the occurrence of DRPs with the intention to identify patients at risk for DRPs to guide and target preventive measures where they are needed most in patients. Design Triangulation process using a mixed methods approach. Methods We conducted an expert panel, using the nominal group technique (NGT) and a qualitative analysis, to gather risk factors for DRPs. The expert panel consisted of two consultant hospital physicians (internal medicine and geriatrics), one emergency physician, one independent general practitioner, one clinical pharmacologist, one clinical pharmacist, one registered nurse, one home care nurse and two independent community pharmacists. The literature was searched for additional risk factors. Gathered factors from the literature search and the NGT were assembled and validated in a two-round Delphi questionnaire. Results The NGT resulted in the identification of 33 items with 13 additional risk factors from the qualitative analysis of the discussion. The literature search delivered another 39 risk factors. The 85 risk factors were refined to produce 42 statements for the Delphi online questionnaire. Of these, 27 risk factors were judged to be ‘important’ or ‘rather important’. Conclusions The gathered risk factors may help to characterise and identify patients at risk for DRPs and may enable clinical pharmacists to guide and target preventive measures in order to limit the occurrence of DRPs. As a further step, these risk factors will serve as the basis for a screening tool to identify patients at risk for DRPs. PMID:25795686
An introduction to quantum chemical methods applied to drug design.
Stenta, Marco; Dal Peraro, Matteo
2011-06-01
The advent of molecular medicine allowed identifying the malfunctioning of subcellular processes as the source of many diseases. Since then, drugs are not only discovered, but actually designed to fulfill a precise task. Modern computational techniques, based on molecular modeling, play a relevant role both in target identification and drug lead development. By flanking and integrating standard experimental techniques, modeling has proven itself as a powerful tool across the drug design process. The success of computational methods depends on a balance between cost (computation time) and accuracy. Thus, the integration of innovative theories and more powerful hardware architectures allows molecular modeling to be used as a reliable tool for rationalizing the results of experiments and accelerating the development of new drug design strategies. We present an overview of the most common quantum chemistry computational approaches, providing for each one a general theoretical introduction to highlight limitations and strong points. We then discuss recent developments in software and hardware resources, which have allowed state-of-the-art of computational quantum chemistry to be applied to drug development.
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.
Drug and alcohol abuse: The pattern and magnitude of the problem
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.
The lattice Boltzmann method and the problem of turbulence
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.
The factorization method for the acoustic transmission problem
NASA Astrophysics Data System (ADS)
Anagnostopoulos, Konstantinos A.; Charalambopoulos, Antonios; Kleefeld, Andreas
2013-11-01
In this work, the shape reconstruction problem of acoustically penetrable bodies from the far-field data corresponding to time-harmonic plane wave incidence is investigated within the framework of the factorization method. Although the latter technique has received considerable attention in inverse scattering problems dealing with impenetrable scatterers and it has not been elaborated for inverse transmission problems with the only exception being a work by the first two authors and co-workers. We aim to bridge this gap in the field of acoustic scattering; the paper on one hand focuses on establishing rigorously the necessary theoretical framework for the application of the factorization method to the inverse acoustic transmission problem. The main outcome of the investigation undertaken is the derivation of an explicit formula for the scatterer's characteristic function, which depends solely on the far-field data feeding the inverse scattering scheme. Extended numerical examples in three dimensions are also presented, where a variety of different surfaces are successfully reconstructed by the factorization method, thus, complementing the method's validation from the computational point of view.
Monitoring of air pollution by plants methods and problems
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.
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…
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.
Simplex method in problems of light-beam phase control.
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
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.
MIMD massively parallel methods for engineering and science problems
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.
Petry, Nancy M.; Rash, Carla J.; Blanco, Carlos
2011-01-01
Identifying situations in which individuals gamble may be important for developing or improving treatments, but few instruments exist for examining high-risk gambling situations. This study evaluated the factor structure of the Inventory of Gambling Situations (IGS), an instrument that assesses situations that may lead to gambling episodes. Individuals seeking alcohol and drug abuse treatment who were identified as problem or pathological gamblers (N = 283) completed the IGS, and principal component analysis revealed a 4-factor solution best fit the data; the factors represented items related to Negative Affect, Positive Affect, Gambling Cues, and Social Situations. Across the whole scale, Cronbach’s alpha was 0.97, ranging from 0.83 to 0.96 for the four factors. IGS total scores correlated with other indices of gambling problems, including number of pathological gambling criteria endorsed and frequency and intensity of gambling. Race, education, and severity of psychiatric, drug and alcohol problems were significantly predictive of some factor scores. Specifically, African Americans were more likely to gamble in response to Negative Affect situations than Caucasians, and education was inversely associated with wagering in response to Gambling Cues. Psychiatric symptoms were predictive of gambling in response to both Positive and Negative Affect situations and Gambling Cues. Severity of drug and alcohol problems were related to gambling in Social Situations. Results from this study indicate that the IGS has good psychometric properties and suggest areas in which intervention efforts may be tailored to prevent or treat gambling problems among individuals seeking substance abuse treatment. PMID:21186927
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.
Case method and casuistry: the problem of bias.
Kopelman, L M
1994-03-01
Case methods of reasoning are persuasive, but we need to address problems of bias in order to use them to reach morally justifiable conclusions. A bias is an unwarranted inclination or a special perspective that disposes us to mistaken or one-sided judgments. The potential for bias arises at each stage of a case method of reasoning including in describing, framing, selecting and comparing of cases and paradigms. A problem of bias occurs because to identify the relevant features for such purposes, we must use general views about what is relevant; but some of our general views are biased, both in the sense of being unwarranted inclinations and in the sense that they are one of many viable perspectives. This reliance upon general views to determine relevancy creates additional difficulties for defenders who maintain that case methods of moral reasoning are not only useful, but more basic, reliable or prior to other forms of moral reasoning. If we cannot identify the case's relevant features and issues independently of our general views or biases, we need further explanation about why a case method or casuistry should be viewed as prior to or more basic or reliable than other forms of moral reasoning. Problems of bias also arise for other methods of reasoning. In medical science, case reviews are regarded as an unreliable way to form generalizations, and methods such as clinical trials are used to address bias.
Multidrug and extensively drug-resistant TB (M/XDR-TB): problems and solutions.
Prasad, Rajendra
2010-10-01
Multi Drug Resistant Tuberculosis (MDR-TB) and Extensively Drug Resistant Tuberculosis (XDR-TB) are posing a threat to the control of tuberculosis. The first WHO-IUATLD antituberculosis drug resistance surveillance carried out in 1994 in 35 countries reported the median prevalence of primary and acquired multi drug resistance as 1.4% and 13% respectively. Subsequently, second, third and fourth WHO-IUATLD global drug resistance surveillances were carried out in 1996-99, 1999-2002 and 2002-2007 respectively. Based on drug resistance information from 114 countries, the proportion of MDR-TB among all cases was estimated for countries with no survey information. It was estimated that 4,89,139 cases of MDR-TB emerged in 2006. China and India carry approximately 50% of the global burden. 35 countries and two Special Administrative Regions (SARs) reported data on XDR-TB for the first time in 2006. Multidrug and extensively drug-resistant TB 2010 Global report on Surveillance and response estimated that 4,40,000 cases of MDR-TB emerged globally in 2008 and caused an estimated 1,50,000 deaths. 5.4% of MDR-TB cases were found to have XDR-TB. To date, a cumulative total of 58 countries have confirmed at least one case of XDR-TB. M/XDR-TB is a man-made problem and its emergence can be prevented by prompt diagnosis and effective use of first line drugs in every new patient. The DOTS Plus proposed by WHO highlights the comprehensive management strategy to control MDR-TB. Laboratory services for adequate and timely diagnosis of M/XDR-TB must be strengthened and programmatic management of M/XDR-TB must be scaled up as per target set by global plan. Proper use of second-line drugs must be ensured to cure existing MDR-TB, to reduce its transmission and to prevent XDR-TB. Sound infection control measures to avoid further transmission of M/XDR-TB and research towards development of new diagnostics, drugs and vaccines should be promoted to control M/XDR-TB.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 49 Transportation 1 2013-10-01 2013-10-01 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 and may result in a requirement for another collection? As the MRO, you must cancel a drug test when...
Changing to problem-oriented methods. Implementation in psychiatric institutions.
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
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.
An adaptive pseudo-spectral method for reaction diffusion problems
NASA Technical Reports Server (NTRS)
Bayliss, A.; Matkowsky, B. J.; Gottlieb, D.; Minkoff, M.
1989-01-01
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.
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.
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.
A multilevel finite element method for Fredholm integral eigenvalue problems
NASA Astrophysics Data System (ADS)
Xie, Hehu; Zhou, Tao
2015-12-01
In this work, we proposed a multigrid finite element (MFE) method for solving the Fredholm integral eigenvalue problems. The main motivation for such studies is to compute the Karhunen-Loève expansions of random fields, which play an important role in the applications of uncertainty quantification. In our MFE framework, solving the eigenvalue problem is converted to doing a series of integral iterations and eigenvalue solving in the coarsest mesh. Then, any existing efficient integration scheme can be used for the associated integration process. The error estimates are provided, and the computational complexity is analyzed. It is noticed that the total computational work of our method is comparable with a single integration step in the finest mesh. Several numerical experiments are presented to validate the efficiency of the proposed numerical method.
An eigenvalue method for solving transient heat conduction problems
NASA Technical Reports Server (NTRS)
Shih, T. M.; Skladany, J. T.
1983-01-01
The eigenvalue method, which has been used by researchers in structure mechanics, is applied to problems in heat conduction. Its formulation is decribed in terms of an examination of transient heat conduction in a square slab. Taking advantage of the availability of the exact solution, we compare the accuracy and other numerical properties of the eigenvalue method with those of existing numerical schemes. The comparsion shows that, overall, the eigenvalue method appears to be fairly attractive. Furthermore, only a few dominant eigenvalues and their corresponding eigenvectors need to be computed and retained to yield reasonably high accuracy. Greater savings are attained in the computation time for a transient problem with long time duration and a large computational domain.
Problems with NIOSH method 2520 for methyl bromide
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.
Are there potential problems with generic substitution of antiepileptic drugs? A review of issues.
Crawford, P; Feely, M; Guberman, A; Kramer, G
2006-04-01
In response to increasing cost pressures, healthcare systems are encouraging the use of generic medicines. This review explores potential problems with generic substitution of antiepileptic drugs (AEDs). A broad search strategy identified approximately 70 relevant articles. Potential problems with generic substitution included: The limited evidence (mainly case reports with some pharmacokinetic studies) appears to support these concerns for older AEDs. As a result, restrictions on use of specific generic AEDs are in place in some countries and recommended by some lay epilepsy organisations. As more AEDs lose patent protection, it is important to examine the question of whether generic substitution may pose problems for patients with epilepsy, and whether there should be safeguards to ensure that both physician and patient are informed when generic substitution occurs.
Saiani, Luisa
2004-01-01
Nurses care for elderly patients at home and in nursing homes but there is lack of data on the caring problems encountered, their causes and the solutions adopted. The aim of the study is to produce the epidemiology of such problems and, at the same time, focus nurses' attention on their causes and avoidability. The process of definition of caring problems (the focus of the study) and the discussion that brought to the draft protocol are described. The final protocol (presented with the data collection forms) is articulated in two phases: a prevalence survey through a random sampling of points estimates in index days over 6 months; a prospective registry over the same period of time of all causes perceived as clinically relevant by the nursing personnel, who will document the suspected risk factors and causes (including specifically drug therapy), and the interventions and measures which are activated.
Projected discrete ordinates methods for numerical transport problems
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.
Optimal least-squares finite element method for elliptic problems
NASA Technical Reports Server (NTRS)
Jiang, Bo-Nan; Povinelli, Louis A.
1991-01-01
An optimal least squares finite element method is proposed for two dimensional and three dimensional elliptic problems and its advantages are discussed over the mixed Galerkin method and the usual least squares finite element method. In the usual least squares finite element method, the second order equation (-Delta x (Delta u) + u = f) is recast as a first order system (-Delta x p + u = f, Delta u - p = 0). The error analysis and numerical experiment show that, in this usual least squares finite element method, the rate of convergence for flux p is one order lower than optimal. In order to get an optimal least squares method, the irrotationality Delta x p = 0 should be included in the first order system.
The making of a public health problem: multi-drug resistant tuberculosis in India.
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
The making of a public health problem: multi-drug resistant tuberculosis in India.
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.
Economic evaluation of drug therapy: a review of the contingent valuation method.
Johannesson, M; Johansson, P O; Jönsson, B
1992-05-01
The aim of this paper is to review the use of the contingent valuation (CV) method in economic evaluation of drug therapy. With the CV method, willingness to pay for a project 'treatment' is measured with survey methods, which makes it possible to carry out traditional cost-benefit analysis. The CV method has been developed in environmental economics and is now the most commonly used method of measuring environmental benefits. Due to the limitations of existing methods, empirical applications are starting to appear in the health field as well. From the empirical applications with respect to drug treatment it is evident that it is possible to achieve acceptable response rates. The methodological problems encountered when measuring willingness to pay with survey methods are similar to the problems encountered when measuring utility and quality of life in cost-utility analysis. It is concluded that further studies with the CV method are necessary to further explore questions concerning the reliability and validity of the method in this field.
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.
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...
Multilevel methods for elliptic problems on unstructured grids
NASA Technical Reports Server (NTRS)
Chan, Tony F.; Go, Susie; Zikatanov, Ludmil
1997-01-01
Multilevel methods on unstructured grids for elliptic problems are reviewed. The advantages of these techniques are the flexible approximation of the boundaries of complicated physical domains and the ability to adapt the grid to the resolution of fine scaled structures. Multilevel methods, which include multigrid methods and domain decomposition methods, depend on the correct splitting of appropriate finite element spaces. The standard splittings used in the structured grid case cannot be directly extended to unstructured grids due to their requirement for a hierarchical grid structure. Issues related to the application of multilevel methods to unstructured grids are discussed, including how the coarse spaces and transfer operators are defined and how different types of boundary conditions are treated. An obvious way to generate a coarse mesh is to regrid the physical domain several times. Several alternatives are proposed and discussed: node nested coarse spaces, agglomerated coarse spaces and algebraically generated coarse spaces.
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…
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…
Kennedy, D G; Cannavan, A; McCracken, R J
2000-06-16
The occurrence of violative residues of veterinary medicines and other, unauthorised, drugs in food of animal origin is an issue of popular concern within the European Union. Violations can occur as a result of improper use of a licensed product or through the illegal use of an unlicensed substance. However, a "violative" analytical result does not necessarily mean that abuse has occurred. Contamination of animal feedingstuffs, environmental contamination and animal-to-animal transfer of drugs can also cause residue violations. This paper reviews these inadvertent causes of residues violations in food, and includes data generated using chromatographic and non-chromatographic methods of analysis.
2014-01-01
Background Patients are at risk of drug-related problems (DRPs) at transition points during hospitalization. The community pharmacist (CP) is often the first healthcare professional patients visit after discharge. CPs lack sufficient information about the patient and so they may be unable to identify problems in medications, which may lead to dispensing the wrong drugs or dosage, and/or giving wrong information. We aim to assess the impact of a complex intervention comprising of medication reconciliation performed at discharge by a hospital pharmacist (HP) with communication between the HP and CP on DRPs during the seven days following discharge. Methods/Design The study is a cluster randomized crossover trial involving 46 care units (each unit corresponding to a cluster) in 22 French hospitals during two consecutive 14-day periods, randomly assigned as ‘experimental’ or ‘control’ (usual care) periods. We will recruit patients older than 18 years of age and visiting the same CP for at least three months. We will exclude patients with a hospital length of stay of more than 21 days, who do not return home or those in palliative care. During the experimental period, the HP will perform a medications reconciliation that will be communicated to the patient. The HP will inform the patient’s CP about the patient’s drug therapy (modification in home medication, acute drugs prescribed, nonprescription treatments, and/or lab results). The primary outcome will be a composite outcome of any kind of drug misuse during the seven days following discharge assessed at day seven (±2) post-discharge by a pharmacist in charge of the study who will contact both patients and CPs by phone. The secondary outcome will be unplanned hospitalizations assessed by phone contact at day 35 (±5) after discharge. We plan to recruit 1,176 patients. Discussion This study will assess the impact of a reconciliation of medications performed at patient discharge followed by communication
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.
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.
Multiple Coarse Grid Multigrid Methods for Solving Elliptic Problems
NASA Technical Reports Server (NTRS)
Xiao, Shengyou; Young, David
1996-01-01
In this paper we describe some classes of multigrid methods for solving large linear systems arising in the solution by finite difference methods of certain boundary value problems involving Poisson's equation on rectangular regions. If parallel computing systems are used, then with standard multigrid methods many of the processors will be idle when one is working at the coarsest grid levels. We describe the use of Multiple Coarse Grid MultiGrid (MCGMG) methods. Here one first constructs a periodic set of equations corresponding to the given system. One then constructs a set of coarse grids such that for each grid corresponding to the grid size h there are four grids corresponding to the grid size 2*h. Multigrid operations such as restriction of residuals and interpolation of corrections are done in parallel at each grid level. For suitable choices of the multigrid operators the MCGMG method is equivalent to the Parallel Superconvergent MultiGrid (PSMG) method of Frederickson and McBryan. The convergence properties of MCGMG methods can be accurately analyzed using spectral methods.
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.
The conservative characteristic FD methods for atmospheric aerosol transport problems
NASA Astrophysics Data System (ADS)
Fu, Kai; Liang, Dong
2016-01-01
In the paper, we develop the new conservative characteristic finite difference methods (C-CFD) for the atmospheric aerosol transport problems. We propose the time second-order and spatial high-order conservative characteristic finite difference methods for the aerosol vertical advection-diffusion process and the two-dimensional conservative characteristic finite difference methods for aerosol horizontal transport process in the second-order splitting algorithm. Based on the characteristic form of advection-diffusion equations tracking back along the characteristic curve, we treat the integrals over the tracking cells at the previous time level by the conservative interpolations and propose to treat the diffusion terms by the average along the characteristics, where the high-order discrete fluxes are obtained by approximating the cumulative mass function and are continuous at the tracking points. The important feature is that the proposed C-CFD schemes preserve mass and have second-order accuracy in time and high-order accuracy in space. Numerical tests are taken to show the accuracy in time and space and mass conservation of our C-CFD schemes, compared with the standard CFD method. A real case of air quality modelling during the 2008 Beijing Olympics and a severe haze in North China are further simulated and analyzed by using our C-CFD algorithm. Simulated results are in good agreement with observations. The developed C-CFD algorithm can be used for efficiently solving large scale atmospheric aerosol transport problems.
Using Inverse Problem Methods with Surveillance Data in Pneumococcal Vaccination
Sutton, Karyn L.; Banks, H. T.; Castillo-Chavez, Carlos
2010-01-01
The design and evaluation of epidemiological control strategies is central to public health policy. While inverse problem methods are routinely used in many applications, this remains an area in which their use is relatively rare, although their potential impact is great. We describe methods particularly relevant to epidemiological modeling at the population level. These methods are then applied to the study of pneumococcal vaccination strategies as a relevant example which poses many challenges common to other infectious diseases. We demonstrate that relevant yet typically unknown parameters may be estimated, and show that a calibrated model may used to assess implemented vaccine policies through the estimation of parameters if vaccine history is recorded along with infection and colonization information. Finally, we show how one might determine an appropriate level of refinement or aggregation in the age-structured model given age-stratified observations. These results illustrate ways in which the collection and analysis of surveillance data can be improved using inverse problem methods. PMID:20209093
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.
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
Variance reduction methods applied to deep-penetration problems
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.
Matched Interface and Boundary Method for Elasticity Interface Problems
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
Constructive methods of invariant manifolds for kinetic problems
NASA Astrophysics Data System (ADS)
Gorban, Alexander N.; Karlin, Iliya V.; Zinovyev, Andrei Yu.
2004-06-01
The concept of the slow invariant manifold is recognized as the central idea underpinning a transition from micro to macro and model reduction in kinetic theories. We present the Constructive Methods of Invariant Manifolds for model reduction in physical and chemical kinetics, developed during last two decades. The physical problem of reduced description is studied in the most general form as a problem of constructing the slow invariant manifold. The invariance conditions are formulated as the differential equation for a manifold immersed in the phase space ( the invariance equation). The equation of motion for immersed manifolds is obtained ( the film extension of the dynamics). Invariant manifolds are fixed points for this equation, and slow invariant manifolds are Lyapunov stable fixed points, thus slowness is presented as stability. A collection of methods to derive analytically and to compute numerically the slow invariant manifolds is presented. Among them, iteration methods based on incomplete linearization, relaxation method and the method of invariant grids are developed. The systematic use of thermodynamics structures and of the quasi-chemical representation allow to construct approximations which are in concordance with physical restrictions. The following examples of applications are presented: nonperturbative deviation of physically consistent hydrodynamics from the Boltzmann equation and from the reversible dynamics, for Knudsen numbers Kn∼1; construction of the moment equations for nonequilibrium media and their dynamical correction (instead of extension of list of variables) to gain more accuracy in description of highly nonequilibrium flows; determination of molecules dimension (as diameters of equivalent hard spheres) from experimental viscosity data; model reduction in chemical kinetics; derivation and numerical implementation of constitutive equations for polymeric fluids; the limits of macroscopic description for polymer molecules, etc.
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).
Pavarin, Raimondo Maria
2006-01-01
2015 subjects were interviewed at musical events and raves in Northern Italy: average age 25.1, 42% female, 67% work, 42% study, 61% have higher certificate of education. 3.8% used drugs for the first time in the last year, and 60% have been using drugs for over 5 years, age of first use 16.3. In the last year, 26% have tried a mix of drugs, 52% alcohol and drugs, 48% have driven after drinking; drug consumption was: marijuana 58%, hashish 55%, cocaine 24%, popper 12%, hallucinogenic mushrooms 13%, ecstasy 13%, amphetamines 13%, Salvia divinorum 11%, LSD 9%, opium 9%, ketamine 7%, heroin 5%. In the last year, 27% subjects had depression, 25.7% anxiety, 23.7% sleep disorders, 15% financial problems, 13% road accidents, 9% addiction, 6% judicial problems. All problems were correlated to CAGE (Cut, Annoyed, Guilty, Eye-opener) test, drug use and mix drug use; psychological problems were higher for females: anxiety for cocaine, memory and psychosomatic for opium, sleeping disorders for crack, anxiety for popper, hallucinations for LSD and hallucinogenic mushrooms.
Panda, Abinash; Pradhan, Supriya; Mohapatra, Gurukrushna; Mohapatra, Jigyansa
2016-01-01
Objectives: The objective of this study is to identify and compare the nature of the drug-related problems (DRPs) associated with self-medication and non-self-medication (drug use guided by a prescription). Materials and Methods: The cross-sectional, observational study was conducted on 1100 adult participants at a convenience sample of six retail private pharmacy counters. The data collection form was based on the Pharmaceutical Care Network Europe version 6.2 classification for DRPs. Descriptive statistics was used to represent the prevalence of DRPs. Chi-square test was used to find out the association between the type of medication and DRPs. Odds ratio (OR) with confidence interval (CI) was computed to find the factors determining the occurrence of DRPs. P < 0.05 was considered to be statistically significant. Data were analyzed using SPSS version 16.0. Results: The prevalence of self-medication was 18.72%. The prevalence of DRPs was 17.36%. In the self-medication group, the prevalence of DRPs was high (40.78%) as compared to the non-self-medication group (11.97%). DRP related to inappropriate drug dosing was observed in 44.83% and 40.45% subjects in self-medication and non-self-medication group, respectively (P < 0.001). The subjects in the self-medication group were about 5 times likely to have a DRP (OR: 5.06, CI: 3.59-7.14, P < 0.001). Conclusions: Self-medication is associated with a higher risk of various DRPs. Since retail pharmacy outlet is often the first point of contact between the patient and the health care system in a developing country, interventions like drug information activities at the retail pharmacy is likely to bring down the DRPs associated with self-medication. PMID:27721536
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.
Kew, William; Mitchell, John B O
2015-09-01
The application of Machine Learning to cheminformatics is a large and active field of research, but there exist few papers which discuss whether ensembles of different Machine Learning methods can improve upon the performance of their component methodologies. Here we investigated a variety of methods, including kernel-based, tree, linear, neural networks, and both greedy and linear ensemble methods. These were all tested against a standardised methodology for regression with data relevant to the pharmaceutical development process. This investigation focused on QSPR problems within drug-like chemical space. We aimed to investigate which methods perform best, and how the 'wisdom of crowds' principle can be applied to ensemble predictors. It was found that no single method performs best for all problems, but that a dynamic, well-structured ensemble predictor would perform very well across the board, usually providing an improvement in performance over the best single method. Its use of weighting factors allows the greedy ensemble to acquire a bigger contribution from the better performing models, and this helps the greedy ensemble generally to outperform the simpler linear ensemble. Choice of data preprocessing methodology was found to be crucial to performance of each method too.
Ophthalmic Drug Dosage Forms: Characterisation and Research Methods
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
Condensed history Monte Carlo methods for photon transport problems
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
New problems arising from old drugs: second-generation effects of acetaminophen.
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
A non-invasive method of qualitative and quantitative measurement of drugs.
Westerman, S T; Gilbert, L M
1981-09-01
Methods for quick qualitative and quantitative evaluation of drug intake are needed, especially during emergency situations such as drug overdose and alcohol intoxication. The electronystagmograph was used in an attempt to develop a non-invasive method for identification of drug intake, and to study the effects of alcohol and other drugs on the vestibular system. Results of the study reveal that alcohol, diazepam, opiates, barbiturates, cocaine, marijuana, and hallucinogenic drugs produce a characteristic printout pattern which can be evaluated qualitatively. This method is a practical, non-invasive, objective procedure that provides rapid assessment of quality of drug intake. Its potential uses are extensive, including such possibilities as evaluation of drug intake in emergency drug overdose situations, monitoring anesthesia during surgery, evaluating drug intake in women about to deliver, (as well as the effects on the newborn), and determining whether or not persons who are being tested on a polygraph are under the influence of drugs.
Diagrammatic Monte Carlo Method for Many-Polaron Problems
NASA Astrophysics Data System (ADS)
Mishchenko, Andrey S.; Nagaosa, Naoto; Prokof'ev, Nikolay
2014-10-01
We introduce the first bold diagrammatic Monte Carlo approach to deal with polaron problems at a finite electron density nonperturbatively, i.e., by including vertex corrections to high orders. Using the Holstein model on a square lattice as a prototypical example, we demonstrate that our method is capable of providing accurate results in the thermodynamic limit in all regimes from a renormalized Fermi liquid to a single polaron, across the nonadiabatic region where Fermi and Debye energies are of the same order of magnitude. By accounting for vertex corrections, the accuracy of the theoretical description is increased by orders of magnitude relative to the lowest-order self-consistent Born approximation employed in most studies. We also find that for the electron-phonon coupling typical for real materials, the quasiparticle effective mass increases and the quasiparticle residue decreases with increasing the electron density at constant electron-phonon coupling strength.
Lancaster, Kari; Duke, Karen; Ritter, Alison
2015-07-01
The notion of 'recovery' as an overarching approach to drug policy remains controversial. This cross-national analysis considers how the problem of drugs was constructed and represented in two key reports on the place of 'recovery' in drug policy, critically examining how the problem of drugs (and the people who use them) are constituted in recovery discourse, and how these problematisations are shaped and disseminated. Bacchi's poststructuralist approach is applied to two documents (one in Britain and one in Australia) to analyse how the 'problem of drugs' and the people who use them are constituted: as problematic users, constraining alternative understandings of the shifting nature of drug use; as responsibilised individuals (in Britain) and as patients (in Australia); as worthy of citizenship in the context of treatment and recovery, silencing the assumption of unworthiness and the loss of rights for those who continue to use drugs in 'problematic' ways. The position of the organisations which produced the reports is considered, with the authority of both organisations resting on their status as independent, apolitical bodies providing 'evidence-based' advice. There is a need to carefully weigh up the desirable and undesirable political effects of these constructions. The meaning of 'recovery' and how it could be realised in policy and practice is still being negotiated. By comparatively analysing how the problem of drugs was produced in 'recovery' discourse in two jurisdictions, at two specific points in the policy debate, we are reminded that ways of thinking about 'problems' reflect specific contexts, and how we are invoked to think about policy responses will be dependent upon these conditions. As 'recovery' continues to evolve, opening up spaces to discuss its contested meanings and effects will be an ongoing endeavour.
Lancaster, Kari; Duke, Karen; Ritter, Alison
2015-07-01
The notion of 'recovery' as an overarching approach to drug policy remains controversial. This cross-national analysis considers how the problem of drugs was constructed and represented in two key reports on the place of 'recovery' in drug policy, critically examining how the problem of drugs (and the people who use them) are constituted in recovery discourse, and how these problematisations are shaped and disseminated. Bacchi's poststructuralist approach is applied to two documents (one in Britain and one in Australia) to analyse how the 'problem of drugs' and the people who use them are constituted: as problematic users, constraining alternative understandings of the shifting nature of drug use; as responsibilised individuals (in Britain) and as patients (in Australia); as worthy of citizenship in the context of treatment and recovery, silencing the assumption of unworthiness and the loss of rights for those who continue to use drugs in 'problematic' ways. The position of the organisations which produced the reports is considered, with the authority of both organisations resting on their status as independent, apolitical bodies providing 'evidence-based' advice. There is a need to carefully weigh up the desirable and undesirable political effects of these constructions. The meaning of 'recovery' and how it could be realised in policy and practice is still being negotiated. By comparatively analysing how the problem of drugs was produced in 'recovery' discourse in two jurisdictions, at two specific points in the policy debate, we are reminded that ways of thinking about 'problems' reflect specific contexts, and how we are invoked to think about policy responses will be dependent upon these conditions. As 'recovery' continues to evolve, opening up spaces to discuss its contested meanings and effects will be an ongoing endeavour. PMID:25962733
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)
Des Jarlais, Don C; Perlis, Theresa E; Stimson, Gerry V; Poznyak, Vladimir
2006-01-01
Background Successful cross-national research requires methods that are both standardized across sites and adaptable to local conditions. We report on the development and implementation of the methodology underlying the survey component of the WHO Drug Injection Study Phase II – a multi-site study of risk behavior and HIV seroprevalence among Injecting Drug Users (IDUs). Methods Standardized operational guidelines were developed by the Survey Coordinating Center in collaboration with the WHO Project Officer and participating site Investigators. Throughout the duration of the study, survey implementation at the local level was monitored by the Coordinating Center. Surveys were conducted in 12 different cities. Prior rapid assessment conducted in 10 cities provided insight into local context and guided survey implementation. Where possible, subjects were recruited both from drug abuse treatment centers and via street outreach. While emphasis was on IDUs, non-injectors were also recruited in cities with substantial non-injecting use of injectable drugs. A structured interview and HIV counseling/testing were administered. Results Over 5,000 subjects were recruited. Subjects were recruited from both drug treatment and street outreach in 10 cities. Non-injectors were recruited in nine cities. Prior rapid assessment identified suitable recruitment areas, reduced drug users' distrust of survey staff, and revealed site-specific risk behaviors. Centralized survey coordination facilitated local questionnaire modification within a core structure, standardized data collection protocols, uniform database structure, and cross-site analyses. Major site-specific problems included: questionnaire translation difficulties; locating affordable HIV-testing facilities; recruitment from drug treatment due to limited/selective treatment infrastructure; access to specific sub-groups of drug users in the community, particularly females or higher income groups; security problems for users
Prediction by neural network methods compared for energy control problems
Surkan, A.J.; Skurikhin, A.N.
1996-10-01
Daily recordings of energy consumption are sequenced to construct a time series that is used to test the accuracy of a variety of neural networks in making one- and two-day demand predictions. Five neural network methods were applied to the same data for a problem of predicting daily energy usage. These included four which were gradient-based, namely, back propagation (BACKPROP), quick-propagation (QUICKPROP), cascade correlation (CASCOR), memory neuron network (MNN), and a correlation-based method called ALOPEX. The observed time series is the only information source used for making predictions. Other supplementary parallel series of independent data can produce improvements. It was demonstrated that these neural network learning algorithms can train networks to predict consistently, one-day-ahead, over one year of set-aside test patterns and reduce the average error to below 19%. Reported is a comparison of applicability of neural networks by programmed simulations of the widely used gradient-based algorithms along with newer algorithms MNN and ALOPEX. The diverse capabilities of these various networks give insights which are a useful basis for selecting further studies.
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…
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)
Skill Acquisition: Compilation of Weak-Method Problem Solutions.
ERIC Educational Resources Information Center
Anderson, John R.
According to the ACT theory of skill acquisition, cognitive skills are encoded by a set of productions, which are organized according to a hierarchical goal structure. People solve problems in new domains by applying weak problem-solving procedures to declarative knowledge they have about this domain. From these initial problem solutions,…
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…
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.
Fríguls, Bibiana; Joya, Xavier; García-Algar, Oscar; Pallás, C R; Vall, Oriol; Pichini, Simona
2010-06-01
Most of the licit and illicit drugs consumed by the breastfeeding woman pass into the milk and can modify the production, volume and composition of the milk, as well as hypothetically have short- and long-term harmful effects on the infant. There is much confusion in the scientific community regarding this issue: should a woman breastfeed her baby while continuing to use prescription drugs and/or drugs of abuse? There are many case reports of clinically significant toxicity in breast-fed infants from some substances used by mothers (such as irritability, vomiting, sedation, respiratory depression, shock), but there are too few data on studies conducted in breastfeeding women and their infants to make a realistic risk assessment. The objective measurement of a drug and/or metabolites in maternal milk is the first step when investigating the amount of drug excreted in milk and subsequently calculating the daily dose administered to the breast-fed infant. The present review reports the analytical methods developed to detect different drugs in the breast milk, listing the principal characteristics and validation parameters, advantages and disadvantages. Furthermore, the mechanisms of drug transfer into breast milk are discussed, the correlation between the concentration of the drug in breast milk and potential adverse outcomes on the infant are described for each drug, and suggested harm minimization strategies and approved breastfeeding recommendations are indicated.
Thick-Restart Laczos Method for Symmetric Eigenvalue Problems
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
An efficient iterative method for the generalized Stokes problem
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.
Don’t Flush! Why Your Drug Disposal Method Matters
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...
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…
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…
A new method to assess Pavlovian conditioning of psychostimulant drug effects.
Damianopoulos, E N; Carey, R J
1994-07-01
Experimental studies of psychoactive drugs by pavlovian drug-conditioning methods, which originally began with investigations of drug-induced responses mediated by the autonomic nervous system, have now been expanded to include drug-induced response effects expressed as modulations of spontaneous motoric behaviors. In the latter application, however, equivalent behavioral response outcomes in post-treatment tests for conditioning can occur following a psychostimulant drug treatment either through drug interference effects on habituation processes, drug-induced stress effects and/or by pavlovian conditioning of the drug-induced motoric activation effect. Current methodologies for the study of pavlovian conditioned drug effects and/or drug sensitization cannot distinguish among these possibilities. This methodological inadequacy was addressed by a modification of the conventional paired-unpaired treatment protocol. In the new protocol, the animal is sequentially placed into two test compartments with the drug treatment administered in conjunction with placement into the second test compartment. This design permits a differentiation of a pavlovian conditioned drug responses from non-conditioned drug effects through continuous measurement of the non-drug behavioral baseline in both the drug and non-drug control treatment groups combined with multiple response measurements and post-treatment tests for conditioning at variable post-conditioning intervals. The present study details the use of the new modified pavlovian protocol with repeated cocaine (10 mg/kg) treatment. A cocaine conditioned response at 1, 7, and 21 days post-conditioning was identified and distinguished from habituation and stress effects.
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.
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...
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.
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.…
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
Palmer, Keith T; D’Angelo, Stefania; Harris, E Clare; Linaker, Cathy; Coggon, David
2014-01-01
Objectives Mental illness and psychotropic drugs have been linked with workplace injury, but few studies have measured exposures and outcomes independently or established their relative timings. To address this shortcoming, we conducted a case-control study nested within a database prospectively recording injury consultations, diagnoses and drug prescriptions. Methods The Clinical Practice Research Datalink logs primary care data for 6% of the British population, coding all consultations (by the Read system) and drug prescriptions. We identified 1,348 patients aged 16-64 years from this database who had consulted a family doctor or hospital over a 20-year period for workplace injury (cases, 479 diagnostic codes) and 6,652 age, sex, and practice-matched controls with no such consultation. Groups were compared in terms of consultations for mental health problems (1,328 codes) and prescription of psychotropic drugs prior to the case’s injury consultation, using conditional logistic regression. Results In total, 1,846 (23%) subjects had at least one psychiatric consultation before the index date and 1,682 (21%) had been prescribed a psychotropic drug. The odds ratio for prior mental health consultation was 1.44 (P<0.001) and that for psychotropic drug treatment was 1.57 (P<0.001). Risks were significantly elevated for several subclasses of mental health diagnosis (e.g. psychosis, neurosis) and for each of the drug classes analysed. Assuming causal relationships, about 9-10% of all workplace injuries leading to medical consultation were attributable to mental illness or psychotropic medication. Conclusions Mental health problems and psychotropic treatments may account for an important minority of workplace injuries. PMID:24627304
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
Ai, Ni; Fan, Xiaohui; Ekins, Sean
2015-06-23
Drug-drug interactions (DDIs) are associated with severe adverse effects that may lead to the patient requiring alternative therapeutics and could ultimately lead to drug withdrawal from the market if they are severe. To prevent the occurrence of DDI in the clinic, experimental systems to evaluate drug interaction have been integrated into the various stages of the drug discovery and development process. A large body of knowledge about DDI has also accumulated through these studies and pharmacovigillence systems. Much of this work to date has focused on the drug metabolizing enzymes such as cytochrome P-450s as well as drug transporters, ion channels and occasionally other proteins. This combined knowledge provides a foundation for a hypothesis-driven in silico approach, using either cheminformatics or physiologically based pharmacokinetics (PK) modeling methods to assess DDI potential. Here we review recent advances in these approaches with emphasis on hypothesis-driven mechanistic models for important protein targets involved in PK-based DDI. Recent efforts with other informatics approaches to detect DDI are highlighted. Besides DDI, we also briefly introduce drug interactions with other substances, such as Traditional Chinese Medicines to illustrate how in silico modeling can be useful in this domain. We also summarize valuable data sources and web-based tools that are available for DDI prediction. We finally explore the challenges we see faced by in silico approaches for predicting DDI and propose future directions to make these computational models more reliable, accurate, and publically accessible.
Methods for comparing drug policies--the utility of composite drug harm indexes.
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
Baba, Koichi; Pudavar, Haridas E; Roy, Indrajit; Ohulchanskyy, Tymish Y; Chen, Yihui; Pandey, Ravindra K; Prasad, Paras N
2007-01-01
A carrier-free method for delivery of a hydrophobic drug in its pure form, using nanocrystals (nanosized crystals), is proposed. To demonstrate this technique, nanocrystals of a hydrophobic photosensitizing anticancer drug, 2-devinyl-2-(1-hexyloxyethyl)pyropheophorbide (HPPH), have been synthesized using the reprecipitation method. The resulting drug nanocrystals were monodispersed and stable in aqueous dispersion, without the necessity of an additional stabilizer (surfactant). As shown by confocal microscopy, these pure drug nanocrystals were taken up by the cancer cells with high avidity. Though the fluorescence and photodynamic activity of the drug were substantially quenched in the form of nanocrystals in aqueous suspension, both these characteristics were recovered under in vitro and in vivo conditions. This recovery of drug activity and fluorescence is possibly due to the interaction of nanocrystals with serum albumin, resulting in conversion of the drug nanocrystals into the molecular form. This was confirmed by demonstrating similar recovery in presence of fetal bovine serum (FBS) or bovine serum albumin (BSA). Under similar treatment conditions, the HPPH in nanocrystal form or in 1% Tween-80/water formulation showed comparable in vitro and in vivo efficacy.
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.
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.
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…
ERIC Educational Resources Information Center
Ohio State Dept. of Education, Columbus. Div. of Vocational Education.
This training manual for emergency medical technicians, one of 14 modules that comprise the Emergency Victim Care textbook, covers crisis intervention and drug related problems. Objectives stated for the two chapters are for the student to be able to describe: treating common mental disturbances, relating to those suffering a crisis in a…
The Needs of Pregnant and Parenting American Indian Women at Risk for Problem Alcohol or Drug Use.
ERIC Educational Resources Information Center
Zahnd, Elaine; Klein, Dorie
1997-01-01
A survey of 171 American Indian women in California who were pregnant or parenting and were considered at risk for problem substance abuse covered demographic information; personal and family history; alcohol, tobacco, and drug use; HIV risk; and a needs assessment regarding health care, economic needs, and parenting and children's needs. (LP)
ERIC Educational Resources Information Center
Asadullin, Azat R.; Galeeva, Elena Kh.; Achmetova, Elvina A.; Nikolaev, Ivan V.
2016-01-01
The urgency of this study has become vivid in the light of the growing problem of prevalence and use of new synthetic drug types. Lately there has been a tendency of expanding the range of psychologically active substances (PAS) used by addicts with the purpose of their illegal taking. The aim of this research is an attempt of systematizing and…
[Increased consumption of drugs among the elderly results in greater risk of problems].
Fastbom, J
2001-04-01
With aging comes an increasing prevalence of diseases and symptoms that frequently require pharmaceutical treatment. However, aging also brings about bodily changes that result in increased effects and prolonged action of many drugs. Multiple drug use--often termed polypharmacy--seen in many elderly individuals, is the most important risk factor for adverse drug reactions (ADR) and increases the risk of drug interactions and poor compliance. ADR's are responsible for about 10% of all hospital admissions of elderly patients. The drugs most commonly involved are cardiovascular, psychotropics and anti-inflammatory agents. Many of these ADR's are dose-dependent and preventable. Drug use has increased over the last few years, largely thanks to the availability of new and effective agents. This calls for increased vigilance and prudence in prescribing for the elderly. PMID:11379169
Iterative method for elliptic problems on regions partitioned into substructures
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.
Law enforcement approaches and measures used in countering illicit drug problems in Thailand.
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
Sanchez, Katherine; Walker, Robrina; Campbell, Aimee N. C.; Greer, Tracy L.; Hu, Mei-Chen; Grannemann, Bruce D.; Nunes, Edward V.; Trivedi, Madhukar H.
2014-01-01
Background Comorbid psychiatric and substance use disorders are common and associated with poorer treatment engagement, retention, and outcomes. This study examines the presence of depressive symptoms and the demographic and clinical correlates in a diverse sample of substance abuse treatment-seekers to better characterize patients with co-occurring depressive symptoms and substance use disorders and understand potential treatment needs. Methods Baseline data from a randomized clinical effectiveness trial of a computer-assisted, web-delivered psychosocial intervention were analyzed. Participants (N=507) were recruited from 10 geographically diverse outpatient drug treatment programs. Assessments included the self-report Patient Health Questionnaire, and measures of coping strategies, social functioning, physical health status, and substance use. Results One-fifth (21%; n=106) of the sample screened positive for depression; those screening positive for depression were significantly more likely to screen positive for anxiety (66.9%) and PTSD (42.9%). After controlling for anxiety and PTSD symptoms, presence of depressive symptoms remained significantly associated with fewer coping strategies (p = .001), greater impairment in social adjustment (p < .001), and poorer health status, (p < .001), but not to days of drug use in the last 90 days (p = .14). Conclusions Depression is a clinically significant problem among substance abusers and, in this study, patients who screened positive for depression were more likely to have co-occurring symptoms of anxiety and PTSD. Additionally, the presence of depressive symptoms was associated with fewer coping strategies and poorer social adjustment. Coping skills are a significant predictor of addiction outcomes and it may be especially important to screen for and enhance coping among depressed patients. Evidence-based interventions that target coping skills and global functioning among substance abusers with depressive symptoms may
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…
Humfleet, G; Muñoz, R; Sees, K; Reus, V; Hall, S
1999-01-01
Previous research suggests higher rates of smoking, and smoking cessation failure, in alcohol- and drug-abusing populations. The present study examined the relationship of alcohol/drug treatment history and current alcohol and marijuana consumption with success in smoking cessation treatment in a smoking clinic population. Participants were 199 smokers; 23% reported a history of alcohol/drug problems, 12.6% reported a history of drug treatment, 78.7% reported alcohol use, and 21.3% reported marijuana use during treatment. Results indicate no significant differences in abstinence rates based on history of alcohol/drug problem or treatment. Differences were found for any current alcohol use but not for marijuana use. Both alcohol use at baseline and any alcohol use during treatment predicted smoking at all follow-up points. Alcohol users had significantly lower quit rates than did participants reporting no use. Neither use of marijuana at baseline nor during treatment predicted outcome. These findings suggest that even low to moderate levels of alcohol consumption during smoking cessation may decrease treatment success. PMID:10189984
Commentary on “Alzheimer’s disease drug development and the problem of the blood-brain barrier”
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
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)
Public Service Advertising and Social Problems: the Case of Drug Abuse Prevention.
ERIC Educational Resources Information Center
McEwen, William J.; Hanneman, Gerhard J.
This paper explores certain findings of a DAIR (Drug Abuse Information Research) project undertaken at the University of Connecticut which is investigating the dissemination and impact of drug abuse information. Specifically, findings regarding audience response to persuasive antidrug abuse messages on television are discussed. On the basis of the…
American Indian Youth and Drugs, 1976-87: A Continuing Problem.
ERIC Educational Resources Information Center
Beauvais, Fred; And Others
1989-01-01
Continuing surveillance of drug use among American Indian adolescents living on reservations shows them to have rates of use higher than those of their non-Indian counterparts. Marijuana use is particularly high. By the seventh grade, a significant number of youth have tried drugs. Few significant gender differences exist. (Author/BJV)
A Simplified Method for Routine Outcome Monitoring after Drug Abuse Treatment
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
Consistency of self-reported drug use events in a mixed methods study of people who inject drugs
Dyal, Stephanie R.; Kral, Alex H.; Gonzalez, Karina Dominguez; Wenger, Lynn; Bluthenthal, Ricky N.
2015-01-01
Background Little is known about the consistency of information provided by people who inject drugs (PWID) during quantitative and qualitative interviews in mixed methods studies. Objectives We illustrate the use of the intraclass correlation coefficient, descriptive statistics, and regression to assess the consistency of information provided during a mixed methods study of PWID living in Los Angeles and San Francisco, California, USA. Methods Age of first use of heroin, methamphetamine, marijuana, powder cocaine, and crack cocaine and first injection of heroin, methamphetamine, and powder cocaine were collected during an interviewer administered computer-assisted personal interview followed by an in-depth qualitative interview (N=102). Results Participants were 63% male, racially/ethnically diverse. 80.4% between the ages of 40 and 60 years old, 89% US-born, and 57% homeless. Consistency of self-reported data was adequate for most drug use events. Exact concordance between quantitative and qualitative measures of age of onset ranged from 18.2% to 50%. Event ordering was consistent across qualitative and quantitative results for 90.2% of participants. Analyses indicated that age of onset for heroin use, heroin injection, and injection of any drug was significantly lower when assessed by qualitative methods as compared to quantitative methods. Conclusion While inconsistency will emerge during mixed method studies, confidence in the timing and ordering of major types of events such as drug initiation episodes appear to be warranted. PMID:25970020
Some aspects of integral transport method for deep penetration problem
Takahashi, H.
1982-01-01
An analytical expression of the integral transport method for an experimental hole in fission reactors has been developed. This analytical method might still be useful for designing a fusion reactor without using large computer machine time.
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.
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.
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.
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
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
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)…
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.
Magnetic hyperthermia controlled drug release in the GI tract: solving the problem of detection
NASA Astrophysics Data System (ADS)
Bear, Joseph C.; Patrick, P. Stephen; Casson, Alfred; Southern, Paul; Lin, Fang-Yu; Powell, Michael J.; Pankhurst, Quentin A.; Kalber, Tammy; Lythgoe, Mark; Parkin, Ivan P.; Mayes, Andrew G.
2016-09-01
Drug delivery to the gastrointestinal (GI) tract is highly challenging due to the harsh environments any drug- delivery vehicle must experience before it releases it’s drug payload. Effective targeted drug delivery systems often rely on external stimuli to effect release, therefore knowing the exact location of the capsule and when to apply an external stimulus is paramount. We present a drug delivery system for the GI tract based on coating standard gelatin drug capsules with a model eicosane- superparamagnetic iron oxide nanoparticle composite coating, which is activated using magnetic hyperthermia as an on-demand release mechanism to heat and melt the coating. We also show that the capsules can be readily detected via rapid X-ray computed tomography (CT) and magnetic resonance imaging (MRI), vital for progressing such a system towards clinical applications. This also offers the opportunity to image the dispersion of the drug payload post release. These imaging techniques also influenced capsule content and design and the delivered dosage form. The ability to easily change design demonstrates the versatility of this system, a vital advantage for modern, patient-specific medicine.
Magnetic hyperthermia controlled drug release in the GI tract: solving the problem of detection
Bear, Joseph C.; Patrick, P. Stephen; Casson, Alfred; Southern, Paul; Lin, Fang-Yu; Powell, Michael J.; Pankhurst, Quentin A.; Kalber, Tammy; Lythgoe, Mark; Parkin, Ivan P.; Mayes, Andrew G.
2016-01-01
Drug delivery to the gastrointestinal (GI) tract is highly challenging due to the harsh environments any drug- delivery vehicle must experience before it releases it’s drug payload. Effective targeted drug delivery systems often rely on external stimuli to effect release, therefore knowing the exact location of the capsule and when to apply an external stimulus is paramount. We present a drug delivery system for the GI tract based on coating standard gelatin drug capsules with a model eicosane- superparamagnetic iron oxide nanoparticle composite coating, which is activated using magnetic hyperthermia as an on-demand release mechanism to heat and melt the coating. We also show that the capsules can be readily detected via rapid X-ray computed tomography (CT) and magnetic resonance imaging (MRI), vital for progressing such a system towards clinical applications. This also offers the opportunity to image the dispersion of the drug payload post release. These imaging techniques also influenced capsule content and design and the delivered dosage form. The ability to easily change design demonstrates the versatility of this system, a vital advantage for modern, patient-specific medicine. PMID:27671546
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.
Use of a problem-based learning exercise to teach the lean 8-step problem-solving method.
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.
A network centrality method for the rating problem.
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
A Network Centrality Method for the Rating Problem
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
A Double-Blind Drug Trial of Treatment in Young Children with Waking Problems.
ERIC Educational Resources Information Center
Richman, Naomi
1985-01-01
Among 22 children with severe waking problems, taking trimeprazine tartrate produced no permanent effect on sleep patterns and a follow-up of 14 children 6 months later showed persisting sleep problems in the majority. (Author/RH)
The Effectiveness of Using the Model Method to Solve Word Problems
ERIC Educational Resources Information Center
Bao, Lei
2016-01-01
The aim of this study is to investigate whether the model method is effective to assist primary students to solve word problems. The model method not only provides students with an opportunity to interpret the problem by drawing the rectangular bar but also helps students to visually represent problem situations and relevant relationships on the…
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.
... 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 ...
Acromioclavicular joint problems in athletes and new methods of management.
Rios, Clifford G; Mazzocca, Augustus D
2008-10-01
The acromioclavicular (AC) complex consists of bony and ligamentous structures that stabilize the upper extremity through the scapula to the axial skeleton. The AC joint pathology in the athlete is generally caused by 1 of 3 processes: trauma (fracture, AC joint separation, or dislocation); AC joint arthrosis (posttraumatic or idiopathic); or distal clavicle osteolysis. This article presents systematically the relevant anatomy, classification, evaluation, and treatment of these disorders. Management of AC joint problems is dictated by the severity and chronicity of the injury, and the patient's needs and expectations.
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.
Method effects: the problem with negatively versus positively keyed items.
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
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.
An Efficient Optimization Method for Solving Unsupervised Data Classification Problems.
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
An Efficient Optimization Method for Solving Unsupervised Data Classification Problems
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
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…
Drugs and adverse reactions: an economic view of a medical problem.
Pedroni, G
1984-01-01
This monograph attempts to show how patient, physician and drug producer should assess the value and risks of a drug from the economic point of view. The value of a drug lies in its efficacy against disease and pain; the risks are the various side effects. A hypothetical example illustrates the evaluation from the point of view of an individual patient. A distinction must be made here between diseases which may prove fatal and those of a less serious nature. This means that a distinction must also be made in evaluating the risks attached to a drug and the individual attitude to side effects. For the physician, the task of recognizing an adverse drug reaction (ADR) is an extremely complex one. A 11-step flow chart for decision making is presented as a benchmark procedure. Several empirical studies on the incidence of ADRs in ambulatory and hospitalized patients are shown to use shortcuts, which are entirely justified in daily medical practice, but questionable in a scientific analysis. For various reasons the drug manufacturer too is anxious to recognize ADRs at an early stage and to avoid them whenever possible. Prolonged clinical trials, however, produce a steep rise in costs and delay the launching of the product, while the additional information obtained is not always comprehensive and exhaustive. Moreover, the mere fact of recognizing an ADR does not mean that it can be prevented. The producer is therefore forced to consider the risks and costs involved in speeding up or delaying the introduction of a product. The fact that the drug has been approved for sale does not automatically release introduction of a product. The fact that the drug has been approved for sale does not automatically release him from the obligation to carry out further intensive monitoring for the entire period that it is on the market.
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.
Quality of drug prescribing in older patients: is there a problem and can we improve it?
Scott, I; Jayathissa, S
2010-01-01
Older patients are at high risk of suboptimal prescribing (overuse, underuse and misuse of drugs), which can lead to serious adverse drug reactions (ADR). About one in four patients admitted to hospital are prescribed at least one inappropriate medication and up to 20% of all inpatient deaths are attributed to potentially preventable ADR. Lists of drugs to avoid (unnecessary or where risks outweigh benefits) and drugs not to be omitted (strong indications if there are no contraindications) can assist in identifying suboptimal prescribing although, to date, no trials have established the ability of such screening, by itself, to improve prescribing quality. Remedial strategies proven to be effective in randomized trials include detailed appraisal of medication lists by multidisciplinary teams, which involve geriatricians and close liaison with specialist clinical pharmacists. A multifaceted quality improvement strategy is proposed that includes an aspirational target of no more than five different drugs be regularly prescribed to vulnerable older patients. Achieving this target involves prioritizing drug selection on the basis of strength of indication which may run counter to current disease-specific clinical guideline recommendations based on trials that have excluded most older patients. Such a strategy is worthy of further evaluation in a multicentre randomized trial. PMID:19712203
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
A numerical method for eigenvalue problems in modeling liquid crystals
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.
Cabot, Joan M; Fuguet, Elisabet; Rosés, Martí
2014-10-13
A novel high-throughput method for determining acidity constants (pKa) by capillary electrophoresis (CE) is developed. The method, based on the use of an internal standard (IS-CE), is implemented as a routine method for accurate experimental pKa determination of drugs undergoing physicochemical measurements in drug discovery laboratories. Just two electropherograms at 2 different pH values are needed to calculate an acidity constant. Several ISs can be used in the same buffer and run to enhance precision. With 3 ISs, for example, the pKa of the test compound (TC) can be obtained in triplicate in less than 3 min of electrophoresis. It has been demonstrated that the IS-CE method eliminates some systematic errors, maintaining, or even increasing the precision of the results compared with other methods. Furthermore, pH buffer instability during electrophoretic runs is not a problem in the IS-CE method. It is also proved that after 16 h of electroseparation using the same buffer vial, pH may change by around one unit; but the pKa calculated by the IS-CE method remains constant. Thus, IS-CE is a powerful high-throughput method for pKa determination in drug discovery and development.
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)
Darke, S; Heather, N; Hall, W; Ward, J; Wodak, A
1991-10-01
The efficient and accurate measurement of recent drug use is an essential component of treatment and research among opioid users. Urinalysis results alone will not give sufficient information to either the clinician or researcher, due to limitations in detection and an inability to distinguish extent of use. The present paper describes a 'recent use episodes method', adapted from the measurement of alcohol consumption, for obtaining self-reported drug use in eleven different drug categories. Reliability and validity data indicate that the method provides a quick means by which accurate information may be obtained on the overall recent drug use of opioid users.
Using concepts from biology to improve problem-solving methods
NASA Astrophysics Data System (ADS)
Goodman, Erik D.; Rothwell, Edward J.; Averill, Ronald C.
2011-06-01
Observing nature has been a cornerstone of engineering design. Today, engineers look not only at finished products, but imitate the evolutionary process by which highly optimized artifacts have appeared in nature. Evolutionary computation began by capturing only the simplest ideas of evolution, but today, researchers study natural evolution and incorporate an increasing number of concepts in order to evolve solutions to complex engineering problems. At the new BEACON Center for the Study of Evolution in Action, studies in the lab and field and in silico are laying the groundwork for new tools for evolutionary engineering design. This paper, which accompanies a keynote address, describes various steps in development and application of evolutionary computation, particularly as regards sensor design, and sets the stage for future advances.
The Intelligence of Dual Simplex Method to Solve Linear Fractional Fuzzy Transportation Problem
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
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.
Iterative methods for stationary convection-dominated transport problems
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.
The workshop on iterative methods for large scale nonlinear problems
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.
A Spectral Elastodynamic Method for Bi-material Interface Problems
NASA Astrophysics Data System (ADS)
Kunnath, R.
2013-12-01
A computational method is proposed for modeling spontaneous propagation of dynamic cracks and slip ruptures at a planar interface between two dissimilar elastic half-spaces. It is based on a spectral formulation of the boundary integral equation method and is suited to parallel computing. The boundary integral equation can be written in two equivalent forms: (a) The tractions can be written as a space-time convolution of the displacement continuities at the interface (b) The displacement discontinuities can be written as a space-time convolution of the tractions on the interface. Prior work on spectral formulation of the boundary integral equation has adopted the former as the starting point. The present work has for its basis the latter form based on a space-time convolution of the tractions. The radiation damping term is then explicitly extracted to avoid singularities in the convolution kernels. Stress and displacement components are given a spectral representation as finite Fourier series in the spatial coordinate along the interface. With the spectral forms introduced, the space-time convolutions are converted to convolutions in time for each Fourier mode. The distinguishing feature of the method is that elastodynamic convolutions are performed over the history of tractions on the interface. Due the continuity of tractions across the interface, this leads to a simpler formulation and form of the convolution kernels, as compared to existing methods. When coupled with a cohesive law or a friction law, the method is of wide applicability for studying spontaneous crack or slip rupture propagation. The limitations of the method are that it is restricted to planar interfaces and semi-infinite geometries.
[Crime under the influence of psychoactive drugs: the problem of the duration of detection].
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
[Non-steroid anti-inflammatory drugs and adverse gastrointestinal effects. An unresolved problem].
López, A
1999-01-01
Non-steroid anti-inflammatory drugs are a class of medicine widely used throughout the world. This is a pharmacological group in continuous growth, to which some new molecules have been added in recent years. The great drawback of non-steroid anti-inflammatory drugs are their adverse effects, outstanding of which due to their frequency and importance being those that occur in the gastrointestinal tract. By means of a search in Medline and other databases, this work reviews the latest data published on the incidence of dyspepsia, gastroduodenal lesions, gastrointestinal complications and mortality associated with consumption of non-steroid anti-inflammatory drugs. Similarly, a brief description is made of the mechanism of lesions to the stomach of the non-steroid anti-inflammatory drugs and the different risk factors that condition the appearance of adverse effects at the gastrointestinal level. Finally, an analysis is made of the preventive strategy and the different medicines that can be used to this end and a contrast is made of the evidence extracted from the different published studies and the reality of the use of the different "gastroprotectors". This review concludes with a series of questions that still remain unresolved concerning treatment with non-steroid anti-inflammatory drugs and their lesions to the stomach.
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.
Parallel Methods for Solving Time-Dependent Problems Using the Fourier-Laplace Transformation
NASA Astrophysics Data System (ADS)
Sheen, Dongwoo
In this paper we summarize recent progresses on the parallel method for solving time-dependent problems using the Fourier-Laplace transformation. These problems arise in the study of elastic wave equations with absorbing boundary conditions, for example. Instead of solving the time-dependent problems in the space-time domain, we solve them as follows. First, take the Fourier-Laplace transformation of given problems originally set in the space-time domain, and consider the corresponding problems in the space-frequency domain which form a set of indefinite, complex-valued elliptic problems. Such problems are solved in a natural parallel manner since each problem is independent of others. The Fourier-Laplace inversion formula will then recover the solution in the space-time domain. Keywords: parallel method, Fourier-Laplace transform, parabolic and hyperbolic problems
A computational method for drug repositioning using publicly available gene expression data
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
On the performance of tensor methods for solving ill-conditioned problems.
Schnabel, Robert B.; Bader, Brett William
2004-09-01
This paper investigates the performance of tensor methods for solving small- and large-scale systems of nonlinear equations where the Jacobian matrix at the root is ill-conditioned or singular. This condition occurs on many classes of problems, such as identifying or approaching turning points in path following problems. The singular case has been studied more than the highly ill-conditioned case, for both Newton and tensor methods. It is known that Newton-based methods do not work well with singular problems because they converge linearly to the solution and, in some cases, with poor accuracy. On the other hand, direct tensor methods have performed well on singular problems and have superlinear convergence on such problems under certain conditions. This behavior originates from the use of a special, restricted form of the second-order term included in the local tensor model that provides information lacking in a (nearly) singular Jacobian. With several implementations available for large-scale problems, tensor methods now are capable of solving larger problems. We compare the performance of tensor methods and Newton-based methods for both small- and large-scale problems over a range of conditionings, from well-conditioned to ill-conditioned to singular. Previous studies with tensor methods only concerned the ends of this spectrum. Our results show that tensor methods are increasingly superior to Newton-based methods as the problem grows more ill-conditioned.
[Vitiligo as an aesthetic problem. Noninvasive therapeutic methods in vitiligo].
Popko, Magdalena; Kacalak-Rzepka, Anna; Bielecka-Grzela, Stanisława; Wesołowska, Jolanta; Klimowicz, Adam; Maleszka, Romuald
2011-01-01
Vitiligo is an idiopathic chronic skin disease that is notable for depigmented macules forming by destruction of melanocytes mediated by cells of the immune system. Vitiligo occurs in 1-2% of the population irrespective of race and without predilection to gender or age. The dynamics and extent of the disease vary widely, ranging from stable cases with isolated minor foci to states showing rapid progression and occupying large areas of the skin. For many patients, the disease represents a serious cosmetic defect which limits their activities in various spheres of life. There are many noninvasive methods of treatment but none of them offers a guarantee of complete therapeutic success. PUVA- and UVB-therapy are recognized as the most effective and most commonly used methods. The management of vitiligo should also include education, cosmetic correction options, and psychotherapy in some cases.
Overset Grid Methods for Multidisciplinary Applications in Rotorcraft Problems
NASA Technical Reports Server (NTRS)
Ahmad, J. U.; VanDalsem, William R. (Technical Monitor)
1996-01-01
A methodology for the coupling of an advanced computational fluid dynamics method based on an overset grid flow-solver and an advanced computational structural dynamics method based on a finite element analysis is presented. Various procedures for the fluid-structure interactions modeling along with their limitations are also discussed. The flight test data for the four-bladed UH-60A Blackhawk helicopter rotor is chosen for the validation of the results. Convergence and accuracy are tested by numerical experiments with a single-bladed rotor. A comparison of airload predictions with flight test data as well as with a rigid blade case is presented. Grid and interpolation related issues for this aeroelastic application are described.
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…
Numerical Methods for Forward and Inverse Problems in Discontinuous Media
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.
Understanding the Global Problem of Drug Addiction is a Challenge for IDARS Scientists
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
Mitra, Shataneek; Maity, Siddhartha; Sa, Biswanath
2015-03-01
The purpose of this work was to evaluate different methods of cross-linking for developing diltiazem-resin complex loaded carboxymethyl xanthan gum (CMXG) hydrogel beads to achieve highest possible drug entrapment and extended release for effective cardio-protection. The hydrogel beads were prepared by ionic cross-linking and dual cross-linking using simultaneous (SIM) and sequential (SEQ) methods. Among the three methods, SEQ method produced smaller sized beads having higher drug entrapment efficacy and prolonged release characteristics as evidenced from mean dissolution time and diffusion coefficient of drug. Keeping the concentration of ionic cross-linker constant, increase in the amount of covalent cross-linker and cross-linking time decreased the drug release. Higher release of the drug in acid solution was attributed to the higher solubility of the basic drug and higher swelling of the matrices in acid solution. Comparison of FTIR spectra, drug content and dissolution profiles indicated that the drug was stable in the beads when kept under stress condition up to 3 months. In conclusion, the sequential method was found superior for producing CMXG hydrogel beads as a prolonged release delivery device in cardiovascular diseases. PMID:25576745
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.
49 CFR 40.205 - How are drug test problems corrected?
Code of Federal Regulations, 2014 CFR
2014-10-01
... the same business day on which you are notified of the problem, transmitting it by fax or courier. (2... information on the same business day on which you are notified of the problem, transmitting it by fax or courier. (3) You must maintain the written documentation of a correction with the CCF. (4) You must...
49 CFR 40.205 - How are drug test problems corrected?
Code of Federal Regulations, 2013 CFR
2013-10-01
... the same business day on which you are notified of the problem, transmitting it by fax or courier. (2... information on the same business day on which you are notified of the problem, transmitting it by fax or courier. (3) You must maintain the written documentation of a correction with the CCF. (4) You must...
49 CFR 40.205 - How are drug test problems corrected?
Code of Federal Regulations, 2012 CFR
2012-10-01
... the same business day on which you are notified of the problem, transmitting it by fax or courier. (2... information on the same business day on which you are notified of the problem, transmitting it by fax or courier. (3) You must maintain the written documentation of a correction with the CCF. (4) You must...
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
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.
Higher order methods for convection-diffusion problems
NASA Astrophysics Data System (ADS)
Murphy, J. D.; Prenter, P. M.
This paper applies C1 cubic Hermite polynomials embedded in an orthogonal collocation scheme to the spatial discretization of the unsteady nonlinear Burgers equation as a model of the equations of fluid mechanics. The temporal discretization is carried out by means of either a noniterative finite difference or an iterative finite difference procedure. Results of this method are compared with those of a second-order finite difference scheme and a splined-cubic Taylor's series scheme. Stability limits are derived and the matrix structure of the several schemes are compared.
Pitch-Up Problem: A Criterion and Method of Evaluation
NASA Technical Reports Server (NTRS)
Sadoff, Melvin
1959-01-01
A method has been described for predicting the probable relative severity of pitch-up of a new airplane design prior to initial flight tests. An illustrative example has been presented which demonstrated the use of this procedure for evaluating the pitch-up behavior of a large, relatively flexible airplane. It has also been shown that for airplanes for which a mild pitch-up tendency is predicted, the wing and tail loads likely to be encountered in pitch-up maneuvers would not assume critical values, even for pilots unfamiliar with pitch-up.
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…
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…
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…
Faces of Change: Do I Have a Problem with Alcohol or Drugs?
... 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 ...
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…
Teenage Pregnancy and Drug Abuse: Sources of Problem Behaviors. ERIC/CUE Digest No. 58.
ERIC Educational Resources Information Center
Bempechat, Janine; And Others
Drug and alcohol abuse and teenage pregnancy are two behaviors manifested by at-risk children that are both a cause and a result of their lack of success in school and possible subsequent dropping out. The distinction between substance use and abuse may be determined using the following criteria: (1) age of onset; (2) physiological responses; (3)…
A comparison of several methods of solving nonlinear regression groundwater flow problems.
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
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.
NASA Astrophysics Data System (ADS)
Chun, Changbum; Sakthivel, Rathinasamy
2010-06-01
The two-point boundary value problems occur in a wide variety of problems in engineering and science. In this paper, we implement the homotopy perturbation method for solving the linear and nonlinear two-point boundary value problems. The main aim of this paper is to compare the performance of the homotopy perturbation method with extended Adomian decomposition method and shooting method. As a result, for the same number of terms, the homotopy perturbation method yields relatively more accurate results with rapid convergence than other methods. The computer symbolic systems such as Maple and Mathematica allow us to perform complicated and tedious calculations.
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
Methods for determining regularization for atmospheric retrieval problems
NASA Astrophysics Data System (ADS)
Steck, Tilman
2002-03-01
The atmosphere of Earth has already been investigated by several spaceborne instruments, and several further instruments will be launched, e.g., NASA's Earth Observing System Aura platform and the European Space Agency's Environmental Satellite. To stabilize the results in atmospheric retrievals, constraints are used in the iteration process. Therefore hard constraints (discretization of the retrieval grid) and soft constraints (regularization operators) are included in the retrieval. Tikhonov regularization is often used as a soft constraint. In this study, different types of Tikhonov operator were compared, and several new methods were developed to determine the optimal strength of the constraint operationally. The resulting regularization parameters were applied successfully to an ozone retrieval from simulated nadir sounding spectra like those expected to be measured by the Tropospheric Emission Spectrometer, which is part of the Aura platform. Retrievals were characterized by means of estimated error, averaging kernel, vertical resolution, and degrees of freedom.
A hybrid method for prediction and repositioning of drug Anatomical Therapeutic Chemical classes.
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.
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…
Streubel, A; Siepmann, J; Bodmeier, R
2003-01-01
The aim of this study was to develop a new preparation method for low density foam-based, floating microparticles and to demonstrate the systems' performance in vitro. Major advantages of the novel preparation technique include: (i) short processing times, (ii) no exposure of the ingredients to high temperatures, (iii) the possibility to avoid toxic organic solvents, and (iv) high encapsulation efficiencies close to 100%. Floating microparticles consisting of polypropylene foam powder, model drug [chlorpheniramine maleate (CPM), diltiazem HCl, theophylline or verapamil HCl] and polymer [Eudragit RS or polymethyl methacrylate (PMMA)] were prepared by soaking the microporous foam carrier with an organic solution of drug and polymer and subsequent drying. The effects of various formulation and processing parameters on the resulting in vitro floating behaviour, internal and external particle morphology, drug loading, in vitro drug release and physical state of the incorporated drug were studied. Good in vitro floating behaviour was observed in most cases and a broad variety of drug release patterns could be achieved by varying the drug loading and type of polymer. Interestingly, PMMA-based microparticles showed incomplete drug release with verapamil HCl. This restriction could be overcome by forming the free base of the drug prior to microparticle preparation. In contrast to the salt, the free base acted as a plasticizer for PMMA, resulting in sufficiently high diffusion coefficients and, consequently, complete drug release. The low density microparticles were compressed into rapidly disintegrating tablets in order to provide an administrable oral dosage form.
Siddiqi, S.H.; Hawkins, J.E.; Laszlo, A.
1985-12-01
A total of 224 recent isolates of Mycobacterium tuberculosis from 163 patients selected to have multidrug resistance were tested against streptomycin (SM), isoniazid, rifampin, and ethambutol (EMB) by the rapid radiometric BACTEC method and two conventional proportion methods: the World Health Organization (WHO) method, using Lowenstein-Jensen medium; and the Veterans Administration reference laboratory for mycobacteria (VA) method, using Middlebrook 7H10 agar medium. The results were compared, focusing on the concentrations of the drugs in all three methods. Among the four drugs tested, most of the discrepancies in measured activity were observed with SM and EMB, generally because of differences in the drug concentrations used by the three methods. A 4-micrograms amount of SM in the BACTEC method was found to be slightly less active than 10 micrograms in the VA method and significantly more active than 4 micrograms of dihydrostreptomycin in the WHO method. With EMB, 2.5 micrograms in BACTEC was similar to 5 micrograms in the VA method and 2 micrograms in the WHO method, while 10 micrograms in the BACTEC method was found to be more active than 10 and 2 micrograms in the VA and WHO methods, respectively. To attain close agreement, drug concentrations used in the BACTEC method should be carefully selected when a comparison is to be made with any conventional method employed in a laboratory. Standardization of in vitro susceptibility testing is greatly needed to achieve uniformity among the test methods used to evaluate tuberculosis therapeutics.
Direct SQP-methods for solving optimal control problems with delays
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.
Tuberculosis in Europe: a problem of drug resistance or much more?
Carvalho, Anna C C; Migliori, Giovanni B; Cirillo, Daniela M
2010-04-01
Tuberculosis has re-emerged as a public health concern in high-income countries in the last few decades. The European region accounts for only 5% of world TB cases. The incidence of new TB cases in Europe varies from very low rates in Scandinavian countries (six to eight cases/100,000 population) to rates as high as 231 cases/100,000 population in Tajikistan; the Russian Federation is eleventh among the 22 high-burden TB countries. The estimated detection rate of new sputum smear-positive pulmonary cases and the treatment success rate in 2007 were poor compared with other WHO regions: 51% of cases were diagnosed and 70% of them completed a full course of anti-TB therapy, which is still a long way from the World Health Assembly targets (detection of 70% of infectious cases and successful treatment of 85% of them). The low success rate is largely attributable to the increasing number of drug-resistant TB cases: Eastern European countries are among those with the highest rates of multidrug-resistant (MDR)-TB (TB resistant to rifampicin and isoniazid) in the world. By the end of September 2009, at least one case of extensively drug-resistant TB (named XDR-TB and defined as a MDR-TB strain with additional resistance to any fluoroquinolone, and to at least one of three injectable drugs used in anti-TB treatment) had been reported by 25 countries in the WHO European Region. In Western Europe, TB continues to cause disease among elderly native-born individuals, although high-risk groups including immigrants, prisoners, HIV-infected persons and drug addicts significantly contribute to the overall burden. Improved TB control in Europe requires a large coordinated effort by all stakeholders, including governments, governmental and non-governmental institutions, as well as the academic and private sectors and affected communities.
Human placental perfusion method in the assessment of transplacental passage of antiepileptic drugs
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.
Larsen, S
1992-04-01
Saami people ("Lapps") and Norwegians make different use of primary health care services, and Larsen and Nergård (1) reported an under-representation of Saami clients at a treatment facility for drug and alcohol problems in Northern Norway in the years 1986-1988. However, Saami and Norwegian groups did not differ in number of days in treatment, number of treatment incidents, mean age or self-reported years of problem drinking. Since it is believed that Saami clients are under-represented in Norwegian treatment facilities because of cultural differences, the location of treatment facilities within a Saami municipality was expected to increase the incidence of Saami clients. The present study investigated the incidence of Saami clients at Karasjok treatment facility during 1988 and 1989, 8 and 9 years after the opening of this treatment centre. All clients registered at Finnmark County's treatment facility for drug and alcohol problems during 1988-89 were categorized as either Saami or Norwegian by their language preference. Unfortunately, the Saami group was still under-represented among clients at this treatment facility. In addition, a significant difference in the sex-ratio between the two groups was found, indicating that Saami women do not use the institution at all. Results are discussed in terms of availability of health services for minority groups.
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.
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.
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.
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
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
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
Numerical Solution of Problems in Calculus of Variations by Homotopy Perturbation Method
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.
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.
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.
A Method of Solving Scheduling Problems Using Improved Guided Genetic Algorithm
NASA Astrophysics Data System (ADS)
Ou, Gyouhi; Tamura, Hiroki; Tanno, Koichi; Tang, Zheng
In this paper, an improved guided genetic algorithm is proposed forJob-shop schueduling problem. The proposed method is improved by genetic algorithm using multipliers which can be adjusted during the search process. The simulation results based on some benchmark problems that proves the proposed method can find better solutions than genetic algorithm and original guided genetic algorithm.
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.
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…
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…
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
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.
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.
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
A Computationally Efficient Meshless Local Petrov-Galerkin Method for Axisymmetric Problems
NASA Technical Reports Server (NTRS)
Raju, I. S.; Chen, T.
2003-01-01
The Meshless Local Petrov-Galerkin (MLPG) method is one of the recently developed element-free methods. The method is convenient and can produce accurate results with continuous secondary variables, but is more computationally expensive than the finite element method. To overcome this disadvantage, a simple Heaviside test function is chosen. The computational effort is significantly reduced by eliminating the domain integral for the axisymmetric potential problems and by simplifying the domain integral for the axisymmetric elasticity problems. The method is evaluated through several patch tests for axisymmetric problems and example problems for which the exact solutions are available. The present method yielded very accurate solutions. The sensitivity of several parameters of the method is also studied.
TranScreen-N: Method for rapid screening of trans-ungual drug delivery enhancers.
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
[Multi-residue method for determination of veterinary drugs and feed additives in meats by HPLC].
Chonan, Takao; Fujimoto, Toru; Ueno, Ken-Ichi; Tazawa, Teijiro; Ogawa, Hiroshi
2007-10-01
A simple and rapid multi-residue method was developed for the determination of 28 kinds of veterinary drugs and feed additives (drugs) in muscle of cattle, pig and chicken. The drugs were extracted with acetonitrile-water (95:5) in a homogenizer and ultrasonic generator. The extracted solution was poured into an alumina column and the drugs were eluted with acetonitrile-water (90:10). The eluate was washed with n-hexane saturated with acetonitrile and then evaporated. The drugs were separated on a Inertsil ODS-3V column (4.6 mm i.d. x 250 mm) with a gradient system of 0.1% phosphoric acid-acetonitrile as the mobile phase, with monitoring at 280 and 340 nm. The recoveries of the 26 kinds of drugs were over 60% from the meats fortified at 0.1 microg/g, and the quantification limits of most drugs were 0.01 microg/g. This proposed method was found to be effective and suitable for the screening of the above drugs in meats.
TranScreen-N: Method for rapid screening of trans-ungual drug delivery enhancers.
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.
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.…
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…
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.…
A least-squares finite element method for incompressible Navier-Stokes problems
NASA Technical Reports Server (NTRS)
Jiang, Bo-Nan
1992-01-01
A least-squares finite element method, based on the velocity-pressure-vorticity formulation, is developed for solving steady incompressible Navier-Stokes problems. This method leads to a minimization problem rather than to a saddle-point problem by the classic mixed method and can thus accommodate equal-order interpolations. This method has no parameter to tune. The associated algebraic system is symmetric, and positive definite. Numerical results for the cavity flow at Reynolds number up to 10,000 and the backward-facing step flow at Reynolds number up to 900 are presented.
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…
A Problem Decompostion Method for Efficient Diagnosis and Interpretation of Multiple Disorders
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.
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
Wang, Huanhuan; Lu, Yayao; Peng, Bo; Qian, Xiaohong; Zhang, Yangjun
2015-06-01
Cytochrome P450 (CYP) enzymes and uridine 5-diphospho-glucuronosyltransferase (UGT) enzymes are critical enzymes for drug metabolism. Both chemical drugs and traditional Chinese medicines are converted to more readily excreted compounds by drug metabolizing enzymes in human livers. Because of the disparate expression of CYP and UGT enzymes among different individuals, accurate quantification of these enzymes is essential for drug pharmacology, drug-drug interactions and drug clinical applications. The research progress in quantitative methods based on liquid chromatography-mass spectrometry for drug metabolizing enzymes in human liver microsomes in the recent decade is reviewed. PMID:26536756
Wang, Huanhuan; Lu, Yayao; Peng, Bo; Qian, Xiaohong; Zhang, Yangjun
2015-06-01
Cytochrome P450 (CYP) enzymes and uridine 5-diphospho-glucuronosyltransferase (UGT) enzymes are critical enzymes for drug metabolism. Both chemical drugs and traditional Chinese medicines are converted to more readily excreted compounds by drug metabolizing enzymes in human livers. Because of the disparate expression of CYP and UGT enzymes among different individuals, accurate quantification of these enzymes is essential for drug pharmacology, drug-drug interactions and drug clinical applications. The research progress in quantitative methods based on liquid chromatography-mass spectrometry for drug metabolizing enzymes in human liver microsomes in the recent decade is reviewed.
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.
Developments in Methods for Measuring the Intestinal Absorption of Nanoparticle-Bound Drugs
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
Microparticles Produced by the Hydrogel Template Method for Sustained Drug Delivery
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
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.
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
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
Durbeej, Natalie; Berman, Anne H; Gumpert, Clara H; Palmstierna, Tom; Kristiansson, Marianne; Alm, Charlotte
2010-12-01
Substance abuse is common among offenders. One method widely used for the detection of substance abuse is screening. This study explored the concurrent validity of the Alcohol Use Disorders Identification Test (AUDIT) and the Drug Use Disorders Identification Test (DUDIT) screening tools in relation to (a) substance abuse and dependency diagnoses and (b) three problem severity domains of the sixth version of the Addiction Severity Index in a sample of 181 suspected offenders with signs of mental health problems. The screening tools showed moderate to high accuracy for identification of dependency diagnoses. The AUDIT was associated with alcohol problem severity, whereas the DUDIT was associated with drug and legal problem severity. Administering the screening tools in the current population yields valid results. However, the suggested cutoff scores should be applied with caution due to the discrepancy between present and previous findings.
ERIC Educational Resources Information Center
United Nations Educational, Scientific and Cultural Organization, Paris (France). Div. of Educational Sciences, Contents & Methods of Educ.
The seminar on the prevention of drug problems in West Africa reported in this document was part of a multidisciplinary program on this theme implemented by Unesco in Ghana and Senegal since 1986, with the financial support of the United Nations Fund for Drug Abuse Control. As part of the program, an epidemiological survey was conducted among the…
Padgett, D K; Struening, E L
1992-10-01
Data from a 1987 survey of 1,260 homeless adults in New York City show that mental problems and substance dependence were significantly linked to beating and sexual assault among women and to several types of injury and victimization among men. The extremely high rates of victimization and injury underscore a need for greater attention to the safety and welfare of homeless people. PMID:1443061
Fukuoka, Yutaka; Takei, Daiki; Ogawa, Hisamichi
2013-01-01
The present study proposed a two-step drug repositioning method based on a protein-protein interaction (PPI) network of two diseases and the similarity of the drugs prescribed for one of the two. In the proposed method, first, lists of disease related genes were obtained from a meta-database called Genotator. Then genes shared by a pair of diseases were sought. At the first step of the method, if a drug having its target(s) in the PPI network, the drug was deemed a repositioning candidate. Because targets of many drugs are still unknown, the similarities between the prescribed drugs for a specific disease were used to infer repositioning candidates at the second step. As a first attempt, we applied the proposed method to four different types of diseases: hypertension, diabetes mellitus, Crohn disease, and autism. Some repositioning candidates were found both at the first and second steps. PMID:23390352
Solving nonlinear system of third-order boundary value problems using block method
NASA Astrophysics Data System (ADS)
See, Phang Pei; Majid, Zanariah Abdul; Suleiman, Mohamed; Ismail, Fudziah Bt; Othman, Khairil Iskandar
2015-05-01
In this paper, we propose an algorithm of two-point block method to solve the nonlinear system of third-order boundary value problems directly. The proposed method is presented in a simple form of Adams type and two approximate solutions will be obtained simultaneously with the block method using variable step size strategy. The method will be implemented with the multiple shooting technique via the three-step iterative method to generate the missing initial value. Most of the existence method will reduce the third-order boundary value problems to a system of first order equations where the systems of six equations need to be solved. The method we proposed in this paper will solve the third-order boundary value problems directly. Two numerical examples are given to illustrate the efficiency of the proposed method.
A Modified Simple Shooting Method for Solving Two-Point Boundary-Value Problems
NASA Astrophysics Data System (ADS)
Holsapple, Raymond; Venkataraman, Ram; Doman, David B.
2002-10-01
In the study of mechanics and optimal control, one often encounters what is called a two-point boundary-value problem (TPBVP). A couple of methods exist for solving these problems, such as the Simple Shooting Method (SSM) and its variation, the Multiple Shooting Method (MSM). In this paper a new method is proposed that was designed from the favorable aspects of both the SSM and the MSM. The Modified Simple Shooting Method (MSSM) sheds undesirable aspects of both previously mentioned methods to yield a superior, faster method for solving TPBVPs. The convergence of the MSSM is proven under mild conditions on the TPBVP. A comparison of the MSM and the MSSM is made for a problem where both methods converge. We also provide a second example where the MSM fails to converge while the MSSM converges rapidly.
Comparative Study of Different Methods for the Prediction of Drug-Polymer Solubility.
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
Comparative Study of Different Methods for the Prediction of Drug-Polymer Solubility.
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.
Methods to Evaluate Biliary Excretion of Drugs in Humans: an Updated Review
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
A Method to Determine the Ability of Drugs to Diffuse through the Blood- Brain Barrier
NASA Astrophysics Data System (ADS)
Seelig, Anna; Gottschlich, Rudolf; Devant, Ralf 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.
Hybrid method of deterministic and probabilistic approaches for multigroup neutron transport problem
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)
The Finite Analytic Method for steady and unsteady heat transfer problems
NASA Technical Reports Server (NTRS)
Chen, C.-J.; Li, P.
1980-01-01
A new numerical method called the Finite Analytical Method for solving partial differential equations is introduced. The basic idea of the finite analytic method is the incorporation of the local analytic solution in obtaining the numerical solution of the problem. The finite analytical method first divides the total region of the problem into small subregions in which local analytic solutions are obtained. Then an algebraic equation is derived from the local analytic solution for each subregion relating an interior nodal value at a point P in the subregion to its neighboring nodal values. The assembly of all the local analytic solutions thus provides the finite-analytic numerical solution of the problem. In this paper the finite analytic method is illustrated in solving steady and unsteady heat transfer problems.
Nonlinear Schwarz-Fas Methods for Unstructured Finite Element Elliptic Problems
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.
Methods Development for Blood Borne Macrophage Carriage of Nanoformulated Antiretroviral Drugs
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
On the use of adaptive moving grid methods in combustion problems
Hyman, J.M.; Larrouturou, B.
1986-01-01
The investigators have presented the reasons and advantages of adaptively moving the mesh points for the solution of time-dependent PDEs (partial differential equations) systems developing sharp gradients, and more specifically for combustion problems. Several available adaptive dynamic rezone methods have been briefly reviewed, and the effectiveness of these algorithms for combustion problems has been illustrated by the numerical solution of a simple flame propagation problem. 29 refs., 7 figs.
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.
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.
The adaptive problems of female teenage refugees and their behavioral adjustment methods for coping
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
Ecological Momentary Assessment of Illicit Drug Use Compared to Biological and Self-Reported Methods
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
Lynch, Kara L.; Breaud, Autumn R.; Vandenberghe, Hilde; Wu, Alan H. B.; Clarke, William
2010-01-01
BACKGROUND Liquid chromatography-mass spectrometry (LC-MS) and tandem LC-MS (LC-MS/MS) are increasingly used in toxicology laboratories as a complementary method to gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-ultraviolet detection (LC-UV) for comprehensive drug screening (CDS). This study was designed to characterize the sensitivity and specificity of three LC-MS(/MS) vendor-supplied methods for targeted CDS and identify the current limitations associated with the use of these technologies. METHODS Five methods for broad spectrum CDS, including LC-UV (REMEDi), full scan GC-MS, LC-MS (ZQ™-Mass Detector with MassLynx™-software), LC-QTRAP-MS/MS (3200-QTRAP® with Cliquid®-software) and LC-LIT-MS/MS (LXQ™ Linear Ion Trap with ToxID™-software) were evaluated based on their ability to detect drugs in 48 patient urine samples. RESULTS The tandem MS methods identified 15% more drugs than the single stage MS or LC-UV methods. Use of two broad spectrum screening methods identified more drugs than any single system alone. False negatives and false positives generated by the LC-MS(/MS) software programs were identified upon manual review of the raw data. CONCLUSIONS The LC-MS/MS methods detected a broader menu of drugs; however, it is essential to establish manual data review criteria for all LC-MS(/MS) drug screening methods. Use of an EI-GC-MS and ESI-LC-MS/MS combination for targeted CDS may be optimal due to the complementary nature of the chromatographic and ionization techniques. PMID:20540936
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.…
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.
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.
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.
Listov, S A; Arsamastsev, A P; Gamanina, G J
1988-10-01
Conventional methods of the determination of sulphur in organic drugs were studied (Schöniger method) and new methods developed. Emphasis was put on the disturbance effect of 5 elements, which often occur in the structure of organic drug compounds. It could be shown, that the disturbance effect of nitrogen and chlorine was overcome by the use of carbamide and ammonium carbonate in the absorption solution. The effect of fluorine was abolished by the use of boric acid and a special two-spiral technique of the analysis. Based on these studies concrete recommendations for the Schöniger method of sulphur determination in drugs of various composition of elements were given. PMID:3212013
Listov, S A; Arsamastsev, A P; Gamanina, G J
1988-10-01
Conventional methods of the determination of sulphur in organic drugs were studied (Schöniger method) and new methods developed. Emphasis was put on the disturbance effect of 5 elements, which often occur in the structure of organic drug compounds. It could be shown, that the disturbance effect of nitrogen and chlorine was overcome by the use of carbamide and ammonium carbonate in the absorption solution. The effect of fluorine was abolished by the use of boric acid and a special two-spiral technique of the analysis. Based on these studies concrete recommendations for the Schöniger method of sulphur determination in drugs of various composition of elements were given.
In silico Prediction of Drug Induced Liver Toxicity Using Substructure Pattern Recognition Method.
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
In silico Prediction of Drug Induced Liver Toxicity Using Substructure Pattern Recognition Method.
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.
A numerical study of hybrid optimization methods for the molecular conformation problems
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.
NASA Astrophysics Data System (ADS)
Fujiwara, Hiroyuki
2000-01-01
The fast multipole method is developed for the solution of the boundary integral equations arising in wave scattering problems involving 3-D topography and 3-D basin problems. When coupled with an iterative solver for linear equations, the fast multipole method can significantly reduce memory requirements. The order of operations for the product of the matrix obtained from the discretization of the integral kernel and a vector is reduced from N2 to the order of pα N, where p is the order of the multipole expansion and α depends on the details of the implementation. In order to achieve efficient implementation the translation operators for the multipole expansion need to be used in the diagonal form based on a spherical wave decomposition. For problems with topography, the number of iterations required of the linear equation solver to achieve convergence is small and no preconditioning is necessary. However, for a basin problem, block-diagonal preconditioning is essential in the application of the iterative solver. Both the memory requirements and the CPU time are considerably reduced for topography problems. Although the memory requirement is reduced for a basin problem used in this numerical experiment, the CPU time would be still longer than that for the ordinary boundary element method if sufficient memory were available. These results indicate that the fast multipole method might be much more efficient than the ordinary method for 3-D elastic wave scattering problems with more than several tens of thousands of unknown variables.
Boundary Value Technique for Initial Value Problems Based on Adams-Type Second Derivative Methods
ERIC Educational Resources Information Center
Jator, S. N.; Sahi, R. K.
2010-01-01
In this article, we propose a family of second derivative Adams-type methods (SDAMs) of order up to 2k + 2 ("k" is the step number) for initial value problems. The methods are constructed through a continuous approximation of the SDAM which is obtained by multistep collocation. The continuous approximation is used to obtain initial value methods,…
NASA Astrophysics Data System (ADS)
Pospelov, A. I.
2016-08-01
Adaptive methods for the polyhedral approximation of the convex Edgeworth-Pareto hull in multiobjective monotone integer optimization problems are proposed and studied. For these methods, theoretical convergence rate estimates with respect to the number of vertices are obtained. The estimates coincide in order with those for filling and augmentation H-methods intended for the approximation of nonsmooth convex compact bodies.
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.…
A bio-inspired method for the constrained shortest path problem.
Wang, Hongping; Lu, Xi; Zhang, Xiaoge; Wang, Qing; Deng, Yong
2014-01-01
The constrained shortest path (CSP) problem has been widely used in transportation optimization, crew scheduling, network routing and so on. It is an open issue since it is a NP-hard problem. In this paper, we propose an innovative method which is based on the internal mechanism of the adaptive amoeba algorithm. The proposed method is divided into two parts. In the first part, we employ the original amoeba algorithm to solve the shortest path problem in directed networks. In the second part, we combine the Physarum algorithm with a bio-inspired rule to deal with the CSP. Finally, by comparing the results with other method using an examples in DCLC problem, we demonstrate the accuracy of the proposed method.
High Order And High Resolution Methods For a Model CAA Problem
NASA Technical Reports Server (NTRS)
Goodrich, John W.
2004-01-01
The initial value problem for the first order linear wave equation in one space dimension is treated for two cases with specified initial data and grid, and data from solutions at t = 400 and t = 800 are presented, as prescribed for Problem 1 in Category 1. Results are shown from computations with a sequence of recently developed high order and high resolution methods which combine Hermite interpolation, Cauchy-Kowaleskya recursion for time derivatives, and Taylor series time advancement. These methods have the same order of accuracy in time as in space. Results are shown from methods that range from third to nineteenth order. The stated problems with the prescribed coarse grid can be simulated with errors that are at the level of machine accuracy if the method is sufficiently high order. In addition, the growth of the maximum absolute error out to t = 100,000 is given for simulations with the stated problem data.
Advanced computational methods for nodal diffusion, Monte Carlo, and S(sub N) problems
NASA Astrophysics Data System (ADS)
Martin, W. R.
1993-01-01
This document describes progress on five efforts for improving effectiveness of computational methods for particle diffusion and transport problems in nuclear engineering: (1) Multigrid methods for obtaining rapidly converging solutions of nodal diffusion problems. An alternative line relaxation scheme is being implemented into a nodal diffusion code. Simplified P2 has been implemented into this code. (2) Local Exponential Transform method for variance reduction in Monte Carlo neutron transport calculations. This work yielded predictions for both 1-D and 2-D x-y geometry better than conventional Monte Carlo with splitting and Russian Roulette. (3) Asymptotic Diffusion Synthetic Acceleration methods for obtaining accurate, rapidly converging solutions of multidimensional SN problems. New transport differencing schemes have been obtained that allow solution by the conjugate gradient method, and the convergence of this approach is rapid. (4) Quasidiffusion (QD) methods for obtaining accurate, rapidly converging solutions of multidimensional SN Problems on irregular spatial grids. A symmetrized QD method has been developed in a form that results in a system of two self-adjoint equations that are readily discretized and efficiently solved. (5) Response history method for speeding up the Monte Carlo calculation of electron transport problems. This method was implemented into the MCNP Monte Carlo code. In addition, we have developed and implemented a parallel time-dependent Monte Carlo code on two massively parallel processors.
Advanced computational methods for nodal diffusion, Monte Carlo, and S[sub N] problems
Martin, W.R.
1993-01-01
This document describes progress on five efforts for improving effectiveness of computational methods for particle diffusion and transport problems in nuclear engineering: (1) Multigrid methods for obtaining rapidly converging solutions of nodal diffusion problems. A alternative line relaxation scheme is being implemented into a nodal diffusion code. Simplified P2 has been implemented into this code. (2) Local Exponential Transform method for variance reduction in Monte Carlo neutron transport calculations. This work yielded predictions for both 1-D and 2-D x-y geometry better than conventional Monte Carlo with splitting and Russian Roulette. (3) Asymptotic Diffusion Synthetic Acceleration methods for obtaining accurate, rapidly converging solutions of multidimensional SN problems. New transport differencing schemes have been obtained that allow solution by the conjugate gradient method, and the convergence of this approach is rapid. (4) Quasidiffusion (QD) methods for obtaining accurate, rapidly converging solutions of multidimensional SN Problems on irregular spatial grids. A symmetrized QD method has been developed in a form that results in a system of two self-adjoint equations that are readily discretized and efficiently solved. (5) Response history method for speeding up the Monte Carlo calculation of electron transport problems. This method was implemented into the MCNP Monte Carlo code. In addition, we have developed and implemented a parallel time-dependent Monte Carlo code on two massively parallel processors.
Numerical study of three-parameter matrix eigenvalue problem by Rayleigh quotient method
NASA Astrophysics Data System (ADS)
Bora, Niranjan; Baruah, Arun Kumar
2016-06-01
In this paper, an attempt is done to find approximate eigenvalues and the corresponding eigenvectors of three-parameter matrix eigenvalue problem by extending Rayleigh Quotient Iteration Method (RQIM), which is generally used to solve generalized eigenvalue problems of the form Ax = λBx. Convergence criteria of RQIM will be derived in terms of matrix 2-norm. We will test the computational efficiency of the Method analytically with the help of numerical examples. All calculations are done in MATLAB software.
Effectiveness of Problem Solving Method In Dynamics And Academic Achievement of High School Students
NASA Astrophysics Data System (ADS)
Ahmadi, F.; Hamidi, F.; Mohammadzadeh, A.; Ahmadi, M. K. A.
2010-07-01
The present research as a per and post tests design with control group investigates the effectiveness of problem solving method as independent variable on academic achievement of students in the second grade of high school in the physics topic of dynamics. The sample consists of four random groups as experimental and control groups which were chosen from the students of the second grade of high school. Each sample consists of 25 participants. The experimental groups were taught in problem solving method without any changing in method for control groups. Data was analyzed using Mixed Analysis Of Variance (MANOVA). Result showed a significant difference between two methods of learning (P<0.05). Further the evaluation of their attitude about problem solving method has been showed that a significant percentage of participants in experimental group were interested to continue that method in other physical topics.
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
Leal, Miguel Costa; Sheridan, Christopher; Osinga, Ronald; Dionísio, Gisela; Rocha, Rui Jorge Miranda; Silva, Bruna; Rosa, Rui; Calado, Ricardo
2014-06-30
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.
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.
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.
[Toxicity of drugs on nasal mucocilia and the method of its evaluation].
Jiang, X G; Cui, J B; Fang, X L; Wei, Y; Xi, N Z
1995-11-01
Effect of solutions or suspensions of eight drugs including analgin, paracetamol, propafenone hydrochloride, propranolol hydrochloride, ephedrine hydrochloride, gentamycin sulfate, sodium deoxycholate and hydrocortisone on ciliary movement were evaluated with in vitro or in situ toad palate model and scanning electron microscope. In vitro toad palate model: 0.2 ml of test drug solution or suspension was applied to a piece of freshly dissected upper palate of toad. The mucocilia were examined with an optical microscope and the lasting time of ciliary movement was recorded after drug application. The upper palate was rinsed with physiological saline when the ciliary movement stopped. The lasting time of ciliary movement after rinsing was then recorded again. In situ palate model: 0.5 ml of test drug solution or suspension was applied to the upper palate of toad for 30 min, and rinsed with physiological saline. The palate was dissected out and the operation was carried out in a similar manner. The results showed that the in situ toad palate model is a satisfactory method for studying the ciliotoxicity of drugs. The in vitro toad palate model is unsuitable for suspension and gel. The results of the eight drugs revealed that ciliary movement is frequently affected by many drugs and, therefore, care must be taken in developing any nasal dosage form to ensure its least ciliotoxicity.
An interpolating boundary element-free method (IBEFM) for elasticity problems
NASA Astrophysics Data System (ADS)
Ren, Hongping; Cheng, Yumin; Zhang, Wu
2010-04-01
The paper begins by discussing the interpolating moving least-squares (IMLS) method. Then the formulae of the IMLS method obtained by Lancaster are revised. On the basis of the boundary element-free method (BEFM), combining the boundary integral equation method with the IMLS method improved in this paper, the interpolating boundary element-free method (IBEFM) for two-dimensional elasticity problems is presented, and the corresponding formulae of the IBEFM for two-dimensional elasticity problems are obtained. In the IMLS method in this paper, the shape function satisfies the property of Kronecker δ function, and then in the IBEFM the boundary conditions can be applied directly and easily. The IBEFM is a direct meshless boundary integral equation method in which the basic unknown quantity is the real solution to the nodal variables. Thus it gives a greater computational precision. Numerical examples are presented to demonstrate the method.
Using a derivative-free optimization method for multiple solutions of inverse transport problems
Armstrong, Jerawan C.; Favorite, Jeffrey A.
2016-01-14
Identifying unknown components of an object that emits radiation is an important problem for national and global security. Radiation signatures measured from an object of interest can be used to infer object parameter values that are not known. This problem is called an inverse transport problem. An inverse transport problem may have multiple solutions and the most widely used approach for its solution is an iterative optimization method. This paper proposes a stochastic derivative-free global optimization algorithm to find multiple solutions of inverse transport problems. The algorithm is an extension of a multilevel single linkage (MLSL) method where a meshmore » adaptive direct search (MADS) algorithm is incorporated into the local phase. Furthermore, numerical test cases using uncollided fluxes of discrete gamma-ray lines are presented to show the performance of this new algorithm.« less
NASA Technical Reports Server (NTRS)
Bauld, N. R., Jr.; Goree, J. G.
1983-01-01
The accuracy of the finite difference method in the solution of linear elasticity problems that involve either a stress discontinuity or a stress singularity is considered. Solutions to three elasticity problems are discussed in detail: a semi-infinite plane subjected to a uniform load over a portion of its boundary; a bimetallic plate under uniform tensile stress; and a long, midplane symmetric, fiber reinforced laminate subjected to uniform axial strain. Finite difference solutions to the three problems are compared with finite element solutions to corresponding problems. For the first problem a comparison with the exact solution is also made. The finite difference formulations for the three problems are based on second order finite difference formulas that provide for variable spacings in two perpendicular directions. Forward and backward difference formulas are used near boundaries where their use eliminates the need for fictitious grid points.
Kim, Y.; Shim, H. J.; Noh, T.
2006-07-01
To resolve the double-heterogeneity (DH) problem resulting from the TRISO fuel of high-temperature gas-cooled reactors (HTGRs), a synergistic combination of a deterministic method and the Monte Carlo method has been proposed. As the deterministic approach, the RPT (Reactivity-equivalent Physical Transformation) method is adopted. In the combined methodology, a reference k-infinite value is obtained by the Monte Carlo method for an initial state of a problem and it is used by the RPT method to transform the original DH problem into a conventional single-heterogeneous one, and the transformed problem is analyzed by the conventional deterministic methods. The combined methodology has been applied to the depletion analysis of typical HTGR fuels including both prismatic block and pebble. The reference solution is obtained using a Monte Carlo code MCCARD and the accuracy of the deterministic-only and the combined methods is evaluated. For the deterministic solution, the DRAGON and HELIOS codes were used. It has been shown that the combined method provides an accurate solution although the deterministic-only solution shows noticeable errors. For the pebble, the two deterministic codes cannot handle the DH problem. Nevertheless, we have shown that the solution of the DRAGON-MCCARD combined approach agrees well with the reference. (authors)
A comparison of acceleration methods for solving the neutron transport k-eigenvalue problem
Willert, Jeffrey; Park, H.; Knoll, D.A.
2014-10-01
Over the past several years a number of papers have been written describing modern techniques for numerically computing the dominant eigenvalue of the neutron transport criticality problem. These methods fall into two distinct categories. The first category of methods rewrite the multi-group k-eigenvalue problem as a nonlinear system of equations and solve the resulting system using either a Jacobian-Free Newton–Krylov (JFNK) method or Nonlinear Krylov Acceleration (NKA), a variant of Anderson Acceleration. These methods are generally successful in significantly reducing the number of transport sweeps required to compute the dominant eigenvalue. The second category of methods utilize Moment-Based Acceleration (or High-Order/Low-Order (HOLO) Acceleration). These methods solve a sequence of modified diffusion eigenvalue problems whose solutions converge to the solution of the original transport eigenvalue problem. This second class of methods is, in our experience, always superior to the first, as most of the computational work is eliminated by the acceleration from the LO diffusion system. In this paper, we review each of these methods. Our computational results support our claim that the choice of which nonlinear solver to use, JFNK or NKA, should be secondary. The primary computational savings result from the implementation of a HOLO algorithm. We display computational results for a series of challenging multi-dimensional test problems.
A comparison of acceleration methods for solving the neutron transport k-eigenvalue problem
NASA Astrophysics Data System (ADS)
Willert, Jeffrey; Park, H.; Knoll, D. A.
2014-10-01
Over the past several years a number of papers have been written describing modern techniques for numerically computing the dominant eigenvalue of the neutron transport criticality problem. These methods fall into two distinct categories. The first category of methods rewrite the multi-group k-eigenvalue problem as a nonlinear system of equations and solve the resulting system using either a Jacobian-Free Newton-Krylov (JFNK) method or Nonlinear Krylov Acceleration (NKA), a variant of Anderson Acceleration. These methods are generally successful in significantly reducing the number of transport sweeps required to compute the dominant eigenvalue. The second category of methods utilize Moment-Based Acceleration (or High-Order/Low-Order (HOLO) Acceleration). These methods solve a sequence of modified diffusion eigenvalue problems whose solutions converge to the solution of the original transport eigenvalue problem. This second class of methods is, in our experience, always superior to the first, as most of the computational work is eliminated by the acceleration from the LO diffusion system. In this paper, we review each of these methods. Our computational results support our claim that the choice of which nonlinear solver to use, JFNK or NKA, should be secondary. The primary computational savings result from the implementation of a HOLO algorithm. We display computational results for a series of challenging multi-dimensional test problems.
ERIC Educational Resources Information Center
Kahan, Meldon; Midmer, Deana; Wilson, Lynn; Borsoi, Diane
2006-01-01
Purpose: To determine knowledge of a national sample of medical students about substance withdrawal, screening and early intervention, medical and psychiatric complications of addiction, and treatment options. Methods: Based on learning objectives developed by medical faculty, twenty-two questions on addictions were included in the 1998 Canadian…
Machine learning plus optical flow: a simple and sensitive method to detect cardioactive drugs
NASA Astrophysics Data System (ADS)
Lee, Eugene K.; Kurokawa, Yosuke K.; Tu, Robin; George, Steven C.; Khine, Michelle
2015-07-01
Current preclinical screening methods do not adequately detect cardiotoxicity. Using human induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs), more physiologically relevant preclinical or patient-specific screening to detect potential cardiotoxic effects of drug candidates may be possible. However, one of the persistent challenges for developing a high-throughput drug screening platform using iPS-CMs is the need to develop a simple and reliable method to measure key electrophysiological and contractile parameters. To address this need, we have developed a platform that combines machine learning paired with brightfield optical flow as a simple and robust tool that can automate the detection of cardiomyocyte drug effects. Using three cardioactive drugs of different mechanisms, including those with primarily electrophysiological effects, we demonstrate the general applicability of this screening method to detect subtle changes in cardiomyocyte contraction. Requiring only brightfield images of cardiomyocyte contractions, we detect changes in cardiomyocyte contraction comparable to - and even superior to - fluorescence readouts. This automated method serves as a widely applicable screening tool to characterize the effects of drugs on cardiomyocyte function.
A miniaturized in vitro release method for investigating drug-release mechanisms.
Ahnfelt, E; Sjögren, E; Axén, N; Lennernäs, H
2015-01-01
We have evaluated a miniaturized in vitro method, based on the μDISS Profiler™ technique that enables on-line monitoring of drug release from a 21 μl sample with 10 ml of release medium. Four model drugs in eight clinically used formulations, including both solid and non-solid drug delivery systems, were investigated. The acquired data were compared with historical in vitro release data from the same formulations. Use of the Weibull function to describe the in vitro drug-release profiles allowed discrimination between the selected formulations with respect to the drug-release mechanisms. Comparison of the release data from the same formulation in different in vitro set-ups showed that the methodology used can affect the mechanism of in vitro release. We also evaluated the ability of the in vitro methods to predict in vivo activity by comparing simulated plasma concentration-time profiles acquired from the application of the biopharmaceutical software GI-Sim to the in vitro observations. In summary, the simulations based on the miniaturized-method release data predicted the plasma profiles as well as or more accurately than simulations based on the historical release data in 71% of the cases and this miniaturized in vitro method appears to be applicable for both solid and non-solid formulations.
Machine learning plus optical flow: a simple and sensitive method to detect cardioactive drugs
Lee, Eugene K.; Kurokawa, Yosuke K.; Tu, Robin; George, Steven C.; Khine, Michelle
2015-01-01
Current preclinical screening methods do not adequately detect cardiotoxicity. Using human induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs), more physiologically relevant preclinical or patient-specific screening to detect potential cardiotoxic effects of drug candidates may be possible. However, one of the persistent challenges for developing a high-throughput drug screening platform using iPS-CMs is the need to develop a simple and reliable method to measure key electrophysiological and contractile parameters. To address this need, we have developed a platform that combines machine learning paired with brightfield optical flow as a simple and robust tool that can automate the detection of cardiomyocyte drug effects. Using three cardioactive drugs of different mechanisms, including those with primarily electrophysiological effects, we demonstrate the general applicability of this screening method to detect subtle changes in cardiomyocyte contraction. Requiring only brightfield images of cardiomyocyte contractions, we detect changes in cardiomyocyte contraction comparable to – and even superior to – fluorescence readouts. This automated method serves as a widely applicable screening tool to characterize the effects of drugs on cardiomyocyte function. PMID:26139150
A hybrid cuckoo search algorithm with Nelder Mead method for solving global optimization problems.
Ali, Ahmed F; Tawhid, Mohamed A
2016-01-01
Cuckoo search algorithm is a promising metaheuristic population based method. It has been applied to solve many real life problems. In this paper, we propose a new cuckoo search algorithm by combining the cuckoo search algorithm with the Nelder-Mead method in order to solve the integer and minimax optimization problems. We call the proposed algorithm by hybrid cuckoo search and Nelder-Mead method (HCSNM). HCSNM starts the search by applying the standard cuckoo search for number of iterations then the best obtained solution is passing to the Nelder-Mead algorithm as an intensification process in order to accelerate the search and overcome the slow convergence of the standard cuckoo search algorithm. The proposed algorithm is balancing between the global exploration of the Cuckoo search algorithm and the deep exploitation of the Nelder-Mead method. We test HCSNM algorithm on seven integer programming problems and ten minimax problems and compare against eight algorithms for solving integer programming problems and seven algorithms for solving minimax problems. The experiments results show the efficiency of the proposed algorithm and its ability to solve integer and minimax optimization problems in reasonable time. PMID:27217988
Zatsiorsky, Vladimir M.
2011-01-01
One of the key problems of motor control is the redundancy problem, in particular how the central nervous system (CNS) chooses an action out of infinitely many possible. A promising way to address this question is to assume that the choice is made based on optimization of a certain cost function. A number of cost functions have been proposed in the literature to explain performance in different motor tasks: from force sharing in grasping to path planning in walking. However, the problem of uniqueness of the cost function(s) was not addressed until recently. In this article, we analyze two methods of finding additive cost functions in inverse optimization problems with linear constraints, so-called linear-additive inverse optimization problems. These methods are based on the Uniqueness Theorem for inverse optimization problems that we proved recently (Terekhov et al., J Math Biol 61(3):423–453, 2010). Using synthetic data, we show that both methods allow for determining the cost function. We analyze the influence of noise on the both methods. Finally, we show how a violation of the conditions of the Uniqueness Theorem may lead to incorrect solutions of the inverse optimization problem. PMID:21311907
A hybrid cuckoo search algorithm with Nelder Mead method for solving global optimization problems.
Ali, Ahmed F; Tawhid, Mohamed A
2016-01-01
Cuckoo search algorithm is a promising metaheuristic population based method. It has been applied to solve many real life problems. In this paper, we propose a new cuckoo search algorithm by combining the cuckoo search algorithm with the Nelder-Mead method in order to solve the integer and minimax optimization problems. We call the proposed algorithm by hybrid cuckoo search and Nelder-Mead method (HCSNM). HCSNM starts the search by applying the standard cuckoo search for number of iterations then the best obtained solution is passing to the Nelder-Mead algorithm as an intensification process in order to accelerate the search and overcome the slow convergence of the standard cuckoo search algorithm. The proposed algorithm is balancing between the global exploration of the Cuckoo search algorithm and the deep exploitation of the Nelder-Mead method. We test HCSNM algorithm on seven integer programming problems and ten minimax problems and compare against eight algorithms for solving integer programming problems and seven algorithms for solving minimax problems. The experiments results show the efficiency of the proposed algorithm and its ability to solve integer and minimax optimization problems in reasonable time.
Terekhov, Alexander V; Zatsiorsky, Vladimir M
2011-02-01
One of the key problems of motor control is the redundancy problem, in particular how the central nervous system (CNS) chooses an action out of infinitely many possible. A promising way to address this question is to assume that the choice is made based on optimization of a certain cost function. A number of cost functions have been proposed in the literature to explain performance in different motor tasks: from force sharing in grasping to path planning in walking. However, the problem of uniqueness of the cost function(s) was not addressed until recently. In this article, we analyze two methods of finding additive cost functions in inverse optimization problems with linear constraints, so-called linear-additive inverse optimization problems. These methods are based on the Uniqueness Theorem for inverse optimization problems that we proved recently (Terekhov et al., J Math Biol 61(3):423-453, 2010). Using synthetic data, we show that both methods allow for determining the cost function. We analyze the influence of noise on the both methods. Finally, we show how a violation of the conditions of the Uniqueness Theorem may lead to incorrect solutions of the inverse optimization problem. PMID:21311907
Terekhov, Alexander V; Zatsiorsky, Vladimir M
2011-02-01
One of the key problems of motor control is the redundancy problem, in particular how the central nervous system (CNS) chooses an action out of infinitely many possible. A promising way to address this question is to assume that the choice is made based on optimization of a certain cost function. A number of cost functions have been proposed in the literature to explain performance in different motor tasks: from force sharing in grasping to path planning in walking. However, the problem of uniqueness of the cost function(s) was not addressed until recently. In this article, we analyze two methods of finding additive cost functions in inverse optimization problems with linear constraints, so-called linear-additive inverse optimization problems. These methods are based on the Uniqueness Theorem for inverse optimization problems that we proved recently (Terekhov et al., J Math Biol 61(3):423-453, 2010). Using synthetic data, we show that both methods allow for determining the cost function. We analyze the influence of noise on the both methods. Finally, we show how a violation of the conditions of the Uniqueness Theorem may lead to incorrect solutions of the inverse optimization problem.
On Development of a Problem Based Learning System for Linear Algebra with Simple Input Method
NASA Astrophysics Data System (ADS)
Yokota, Hisashi
2011-08-01
Learning how to express a matrix using a keyboard inputs requires a lot of time for most of college students. Therefore, for a problem based learning system for linear algebra to be accessible for college students, it is inevitable to develop a simple method for expressing matrices. Studying the two most widely used input methods for expressing matrices, a simpler input method for expressing matrices is obtained. Furthermore, using this input method and educator's knowledge structure as a concept map, a problem based learning system for linear algebra which is capable of assessing students' knowledge structure and skill is developed.
Solution of second order quasi-linear boundary value problems by a wavelet method
Zhang, Lei; Zhou, Youhe; Wang, Jizeng
2015-03-10
A wavelet Galerkin method based on expansions of Coiflet-like scaling function bases is applied to solve second order quasi-linear boundary value problems which represent a class of typical nonlinear differential equations. Two types of typical engineering problems are selected as test examples: one is about nonlinear heat conduction and the other is on bending of elastic beams. Numerical results are obtained by the proposed wavelet method. Through comparing to relevant analytical solutions as well as solutions obtained by other methods, we find that the method shows better efficiency and accuracy than several others, and the rate of convergence can even reach orders of 5.8.
NASA Astrophysics Data System (ADS)
Tang, Xiaojun
2016-04-01
The main purpose of this work is to provide multiple-interval integral Gegenbauer pseudospectral methods for solving optimal control problems. The latest developed single-interval integral Gauss/(flipped Radau) pseudospectral methods can be viewed as special cases of the proposed methods. We present an exact and efficient approach to compute the mesh pseudospectral integration matrices for the Gegenbauer-Gauss and flipped Gegenbauer-Gauss-Radau points. Numerical results on benchmark optimal control problems confirm the ability of the proposed methods to obtain highly accurate solutions.
Multigrid for the Galerkin least squares method in linear elasticity: The pure displacement problem
Yoo, Jaechil
1996-12-31
Franca and Stenberg developed several Galerkin least squares methods for the solution of the problem of linear elasticity. That work concerned itself only with the error estimates of the method. It did not address the related problem of finding effective methods for the solution of the associated linear systems. In this work, we prove the convergence of a multigrid (W-cycle) method. This multigrid is robust in that the convergence is uniform as the parameter, v, goes to 1/2 Computational experiments are included.
Prospects of Applying Enhanced Semi-Empirical QM Methods for 2101 Virtual Drug Design.
Yilmazer, Nusret Duygu; Korth, Martin
2016-01-01
The last five years have seen a renaissance of semiempirical quantum mechanical (SQM) methods in the field of virtual drug design, largely due to the increased accuracy of so-called enhanced SQM approaches. These methods make use of additional terms for treating dispersion (D) and hydrogen bond (H) interactions with an accuracy comparable to dispersion-corrected density functional theory (DFT-D). DFT-D in turn was shown to provide an accuracy comparable to the most sophisticated QM approaches when it comes to non-covalent intermolecular forces, which usually dominate the protein/ligand interactions that are central to virtual drug design. Enhanced SQM methods thus offer a very promising way to improve upon the current state of the art in the field of virtual drug design. PMID:27183985
He, Jingjing; Luo, Zhigang; Huang, Lan; He, Jiuming; Chen, Yi; Rong, Xianfang; Jia, Shaobo; Tang, Fei; Wang, Xiaohao; Zhang, Ruiping; Zhang, Jianjun; Shi, Jiangong; Abliz, Zeper
2015-01-01
Elucidation of the mechanism of action for drug candidates is fundamental to drug development, and it is strongly facilitated by metabolomics. Herein, we developed an imaging metabolomics method based on air-flow-assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI) under ambient conditions. This method was subsequently applied to simultaneously profile a novel anti-insomnia drug candidate, N(6)-(4-hydroxybenzyl)-adenosine (NHBA), and various endogenous metabolites in rat whole-body tissue sections after the administration of NHBA. The principal component analysis (PCA) represented by an intuitive color-coding scheme based on hyperspectral imaging revealed in situ molecular profiling alterations in response to stimulation of NHBA, which are in a very low intensity and hidden in massive interferential peaks. We found that the abundance of six endogenous metabolites changed after drug administration. The spatiotemporal distribution indicated that five altered molecules—including neurotransmitter γ-aminobutyric acid, neurotransmitter precursors choline and glycerophosphocholine, energy metabolism-related molecules adenosine (an endogenous sleep factor), and creatine—are closely associated with insomnia or other neurological disorders. These findings not only provide insights into a deep understanding on the mechanism of action of NHBA, but also demonstrate that the AFADESI-MSI-based imaging metabolomics is a powerful technique to investigate the molecular mechanism of drug action, especially for drug candidates with multitarget or undefined target in the preclinical study stage.
Gestal, J J
1987-01-01
Except for infectious diseases all the main occupational hazards affecting health workers are reviewed: accidents (explosions, fires, electrical accidents, and other sources of injury); radiation (stochastic and non-stochastic effects, protective measures, and personnel most at risk); exposure to noxious chemicals, whose effects may be either local (allergic eczema) or generalised (cancer, mutations), particular attention being paid to the hazards presented by formol, ethylene oxide, cytostatics, and anaesthetic gases; drug addiction (which is more common among health workers than the general population) and psychic problems associated with promotion, shift work, and emotional stress; and assault (various types of assault suffered by health workers, its causes, and the characterisation of the most aggressive patients). PMID:3307896
Small, Serena S; Badke, Katherin; Wickham, Maeve E; Bailey, Chantelle; Chruscicki, Adam; Ackerley, Christine; Balka, Ellen; Hohl, Corinne M
2016-01-01
Background Adverse drug events (ADEs) are unintended and harmful events related to medication use. Up to 30% of serious ADEs recur within six months because culprit drugs are unintentionally represcribed and redispensed. Improving the electronic communication of ADE information between care providers, and across care settings, has the potential to reduce recurrent ADEs. Objective We aim to describe the methods used to design Action ADE, a novel electronic ADE reporting system that can be leveraged to prevent unintentional reexposures to harmful drugs in British Columbia, Canada. Methods To develop the new system, our team will use action research and participatory design, approaches that employ social scientific research methods and practitioner participation to generate insights into work settings and problem resolution. We will develop a systematic search strategy to review existing ADE reporting systems identified in academic and grey literature, and analyze the content of these systems to identify core data fields used to communicate ADE information. We will observe care providers in the emergency departments and on the wards of two urban tertiary hospitals and one urban community hospital, in one rural ambulatory care center, and in three community pharmacies in British Columbia, Canada. We will also conduct participatory workshops with providers to understand their needs and priorities related to communicating ADEs and preventing erroneous represcribing or redispensing of culprit medications. These methods will inform the iterative development of a preliminary paper-based reporting form, which we will then pilot test with providers in a real-world setting. Results This is an ongoing project with results being published as analyses are completed. The systematic review has been completed; field observations, focus groups, and pilot testing of a preliminary paper-based design are ongoing. Results will inform the development of software that will enable
A Microfluidic Channel Method for Rapid Drug-Susceptibility Testing of Pseudomonas aeruginosa
Matsumoto, Yoshimi; Grushnikov, Andrey; Kikuchi, Kazuma; Noji, Hiroyuki; Yamaguchi, Akihito; Yagi, Yasushi
2016-01-01
The recent global increase in the prevalence of antibiotic-resistant bacteria and lack of development of new therapeutic agents emphasize the importance of selecting appropriate antimicrobials for the treatment of infections. However, to date, the development of completely accelerated drug susceptibility testing methods has not been achieved despite the availability of a rapid identification method. We proposed an innovative rapid method for drug susceptibility testing for Pseudomonas aeruginosa that provides results within 3 h. The drug susceptibility testing microfluidic (DSTM) device was prepared using soft lithography. It consisted of five sets of four microfluidic channels sharing one inlet slot, and the four channels are gathered in a small area, permitting simultaneous microscopic observation. Antimicrobials were pre-introduced into each channel and dried before use. Bacterial suspensions in cation-adjusted Mueller–Hinton broth were introduced from the inlet slot and incubated for 3 h. Susceptibilities were microscopically evaluated on the basis of differences in cell numbers and shapes between drug-treated and control cells, using dedicated software. The results of 101 clinically isolated strains of P. aeruginosa obtained using the DSTM method strongly correlated with results obtained using the ordinary microbroth dilution method. Ciprofloxacin, meropenem, ceftazidime, and piperacillin caused elongation in susceptible cells, while meropenem also induced spheroplast and bulge formation. Morphological observation could alternatively be used to determine the susceptibility of P. aeruginosa to these drugs, although amikacin had little effect on cell shape. The rapid determination of bacterial drug susceptibility using the DSTM method could also be applicable to other pathogenic species, and it could easily be introduced into clinical laboratories without the need for expensive instrumentation. PMID:26872134
The linearized characteristics method and its application to practical nonlinear supersonic problems
NASA Technical Reports Server (NTRS)
Ferri, Antonio
1952-01-01
The methods of characteristics has been linearized by assuming that the flow field can be represented as a basic flow field determined by nonlinearized methods and a linearized superposed flow field that accounts for small changes of boundary conditions. The method has been applied to two-dimensional rotational flow where the basic flow is potential flow and to axially symmetric problems where conical flows have been used as the basic flows. In both cases the method allows the determination of the flow field to be simplified and the numerical work to be reduced to a few calculations. The calculations of axially symmetric flow can be simplified if tabulated values of some coefficients of the conical flow are obtained. The method has also been applied to slender bodies without symmetry and to some three-dimensional wing problems where two-dimensional flow can be used as the basic flow. Both problems were unsolved before in the approximation of nonlinear flow.
Stathopoulos, A.; Fischer, C.F.; Saad, Y.
1994-12-31
The solution of the large, sparse, symmetric eigenvalue problem, Ax = {lambda}x, is central to many scientific applications. Among many iterative methods that attempt to solve this problem, the Lanczos and the Generalized Davidson (GD) are the most widely used methods. The Lanczos method builds an orthogonal basis for the Krylov subspace, from which the required eigenvectors are approximated through a Rayleigh-Ritz procedure. Each Lanczos iteration is economical to compute but the number of iterations may grow significantly for difficult problems. The GD method can be considered a preconditioned version of Lanczos. In each step the Rayleigh-Ritz procedure is solved and explicit orthogonalization of the preconditioned residual ((M {minus} {lambda}I){sup {minus}1}(A {minus} {lambda}I)x) is performed. Therefore, the GD method attempts to improve convergence and robustness at the expense of a more complicated step.
A Meshless Method Using Radial Basis Functions for Beam Bending Problems
NASA Technical Reports Server (NTRS)
Raju, I. S.; Phillips, D. R.; Krishnamurthy, T.
2004-01-01
A meshless local Petrov-Galerkin (MLPG) method that uses radial basis functions (RBFs) as trial functions in the study of Euler-Bernoulli beam problems is presented. RBFs, rather than generalized moving least squares (GMLS) interpolations, are used to develop the trial functions. This choice yields a computationally simpler method as fewer matrix inversions and multiplications are required than when GMLS interpolations are used. Test functions are chosen as simple weight functions as they are in the conventional MLPG method. Compactly and noncompactly supported RBFs are considered. Noncompactly supported cubic RBFs are found to be preferable. Patch tests, mixed boundary value problems, and problems with complex loading conditions are considered. Results obtained from the radial basis MLPG method are either of comparable or better accuracy than those obtained when using the conventional MLPG method.
An equivalent domain integral method for three-dimensional mixed-mode fracture problems
NASA Technical Reports Server (NTRS)
Shivakumar, K. N.; Raju, I. S.
1991-01-01
A general formulation of the equivalent domain integral (EDI) method for mixed mode fracture problems in cracked solids is presented. The method is discussed in the context of a 3-D finite element analysis. The J integral consists of two parts: the volume integral of the crack front potential over a torus enclosing the crack front and the crack surface integral due to the crack front potential plus the crack face loading. In mixed mode crack problems the total J integral is split into J sub I, J sub II, and J sub III representing the severity of the crack front in three modes of deformations. The direct and decomposition methods are used to separate the modes. These two methods were applied to several mixed mode fracture problems, were analyzed, and results were found to agree well with those available in the literature. The method lends itself to be used as a post-processing subroutine in a general purpose finite element program.
Lasseter, T.J.
1985-02-01
The variable-flux-weighting method has been shown to largely eliminate numerical diffusion at saturation discontinuities in two-phase flow in two-dimensional problems. The method has been extended to multidimensional problems including gravity and capillarity. The method is derived from fractional flow theory and involves the computation of a variable weighting factor for the interface fractional flow between grid blocks. In order to eliminate numerical diffusion at shocks, the appropriate weighting has been found to be downstream weighting just ahead of the shock and upstream weighting otherwise. In one-dimension, the saturation distribution for two-phase flow including gravity has been solved and compared with the analytical solution. The comparison is very good with no numerical diffusion apparent at the saturation discontinuity. Problems including capillarity have also been solved. In this case there is no saturation discontinuity, but the method introduces downstream weighting at the upstream edge of the capillary fringe which effectively eliminates any significant numerical diffusion. Two- and three-dimensional problems have also been solved which demonstrate the accuracy of the method. For three-dimensional problems, the current implementation of the VFW method is ten times slower than an upstream-weighting IMPES method.
Boison, Joe O
2016-05-01
The Joint Food and Agriculture Organization and World Health Organization (FAO/WHO) Expert Committee on Food Additives (JECFA) is one of three Codex committees tasked with applying risk analysis and relying on independent scientific advice provided by expert bodies organized by FAO/WHO when developing standards. While not officially part of the Codex Alimentarius Commission structure, JECFA provides independent scientific advice to the Commission and its specialist committees such as the Codex Committee on Residues of Veterinary Drugs in Foods (CCRVDF) in setting maximum residue limits (MRLs) for veterinary drugs. Codex methods of analysis (Types I, II, III, and IV) are defined in the Codex Procedural Manual as are criteria to be used for selecting methods of analysis. However, if a method is to be used under a single laboratory condition to support regulatory work, it must be validated according to an internationally recognized protocol and the use of the method must be embedded in a quality assurance system in compliance with ISO/IEC 17025:2005. This paper examines the attributes of the methods used to generate residue depletion data for drug registration and/or licensing and for supporting regulatory enforcement initiatives that experts consider to be useful and appropriate in their assessment of methods of analysis. Copyright © 2016 Her Majesty the Queen in Right of Canada. Drug Testing and Analysis © 2016 John Wiley & Sons, Ltd. PMID:27443214
Detection of drug resistance in Mycobacterium tuberculosis: Methods, principles and applications.
Gupta, Anamika; Anupurba, Shampa
2015-01-01
The growing emergence of multidrug resistant tuberculosis (MDR-TB) strains is obstructing efforts for the control and management of TB. Proper management of MDR-TB relies on early recognition of drug resistance followed by timely treatment initiation. Several diagnostic methods, both phenotypic and molecular, have been developed in last few years for rapid identification of drug resistant (DR)-TB. Revised national tuberculosis control programmes (RNTPs) may find it tough to choose from the puzzling variety of rapid tests. Here, we present an outline of the available methods, discussing their basis, advantages and deficiencies. PMID:25857561
Evaluation of contents-based image retrieval methods for a database of logos on drug tablets
NASA Astrophysics Data System (ADS)
Geradts, Zeno J.; Hardy, Huub; Poortman, Anneke; Bijhold, Jurrien
2001-02-01
In this research an evaluation has been made of the different ways of contents based image retrieval of logos of drug tablets. On a database of 432 illicitly produced tablets (mostly containing MDMA), we have compared different retrieval methods. Two of these methods were available from commercial packages, QBIC and Imatch, where the implementation of the contents based image retrieval methods are not exactly known. We compared the results for this database with the MPEG-7 shape comparison methods, which are the contour-shape, bounding box and region-based shape methods. In addition, we have tested the log polar method that is available from our own research.
Hunt, Geoffrey; Moloney, Molly; Fazio, Adam
2012-01-01
Qualitative research is often conceptualized as inherently small-scale research, primarily conducted by a lone researcher enmeshed in extensive and long-term fieldwork or involving in-depth interviews with a small sample of 20 to 30 participants. In the study of illicit drugs, traditionally this has often been in the form of ethnographies of drug-using subcultures. Such small-scale projects have produced important interpretive scholarship that focuses on the culture and meaning of drug use in situated, embodied contexts. Larger-scale projects are often assumed to be solely the domain of quantitative researchers, using formalistic survey methods and descriptive or explanatory models. In this paper, however, we will discuss qualitative research done on a comparatively larger scale—with in-depth qualitative interviews with hundreds of young drug users. Although this work incorporates some quantitative elements into the design, data collection, and analysis, the qualitative dimension and approach has nevertheless remained central. Larger-scale qualitative research shares some of the challenges and promises of smaller-scale qualitative work including understanding drug consumption from an emic perspective, locating hard-to-reach populations, developing rapport with respondents, generating thick descriptions and a rich analysis, and examining the wider socio-cultural context as a central feature. However, there are additional challenges specific to the scale of qualitative research, which include data management, data overload and problems of handling large-scale data sets, time constraints in coding and analyzing data, and personnel issues including training, organizing and mentoring large research teams. Yet large samples can prove to be essential for enabling researchers to conduct comparative research, whether that be cross-national research within a wider European perspective undertaken by different teams or cross-cultural research looking at internal divisions
Hunt, Geoffrey; Moloney, Molly; Fazio, Adam
2011-12-21
Qualitative research is often conceptualized as inherently small-scale research, primarily conducted by a lone researcher enmeshed in extensive and long-term fieldwork or involving in-depth interviews with a small sample of 20 to 30 participants. In the study of illicit drugs, traditionally this has often been in the form of ethnographies of drug-using subcultures. Such small-scale projects have produced important interpretive scholarship that focuses on the culture and meaning of drug use in situated, embodied contexts. Larger-scale projects are often assumed to be solely the domain of quantitative researchers, using formalistic survey methods and descriptive or explanatory models.In this paper, however, we will discuss qualitative research done on a comparatively larger scale-with in-depth qualitative interviews with hundreds of young drug users. Although this work incorporates some quantitative elements into the design, data collection, and analysis, the qualitative dimension and approach has nevertheless remained central. Larger-scale qualitative research shares some of the challenges and promises of smaller-scale qualitative work including understanding drug consumption from an emic perspective, locating hard-to-reach populations, developing rapport with respondents, generating thick descriptions and a rich analysis, and examining the wider socio-cultural context as a central feature. However, there are additional challenges specific to the scale of qualitative research, which include data management, data overload and problems of handling large-scale data sets, time constraints in coding and analyzing data, and personnel issues including training, organizing and mentoring large research teams. Yet large samples can prove to be essential for enabling researchers to conduct comparative research, whether that be cross-national research within a wider European perspective undertaken by different teams or cross-cultural research looking at internal divisions and
Rewarding results: Improving the quality of treatment for people with alcohol and drug problems.
2004-03-01
Substance use disorders are the nation's number one health problem, and lie at the root of many public safety and workplace issues. Improving quality of treatment is as important as improving access to treatment. Leadership for improvement must come from many sources: Congress, SAMHSA, state legislatures, state and local treatment agencies, criminal justice, welfare and other public agencies, employers and managed care organizations, providers, and community leaders. We hope that our report helps leaders see ways to improve treatment quality. Our recommendations can be summed up in a single phrase: reward results. We recognize that there are many avenues for treatment quality improvement, including training, credentialing, best practice dissemination, work force development, facility licensing standards, improvement and implementation of new models for treatment of dual diagnosis patients. We believe, however, that rewarding results is essential to motivating action for improvement. We also believe that if providers receive rewards for improved results, they will creatively open new avenues for improvement--a focus on results gives greater freedom than more detailed mandates for change. Finally, we believe that rewards for result may lead to a restructured treatment system with greater stability and correspondingly greater capacity to improve. While we have placed central emphasis on the role of institutional buyers and managers of care, we believe that the voices of patients and families must be heard. People who have progressed to the stage of recovery, and their families, often have essential insight into what did and did not work for them--their personal stories are frequently compelling and persuasive. We also believe that providers of treatment for substance use disorders are profoundly committed to serving their patients, and often have great understanding of what works. Wise managers will listen very carefully and systematically to the voices of consumers
Lamichhane, Sujan; Gallo, Annemarie; Mani, Gopinath
2014-06-01
Some polymer coatings used in drug-eluting stents (DES) cause adverse reactions. Hence, the use of self-assembled monolayers (SAMs) as a polymer-free platform to deliver an anti-proliferative drug (paclitaxel-PAT) from 2D metal substrates was previously demonstrated. In this study, we optimized the PAT coating on SAMs coated 3D coronary stents. For the optimization process, we investigated the effects of solvents (ethanol, DMSO, and their mixtures), drug concentrations (2, 3, 4, 8, and 12 mg/mL) in the coating solution, and coating methods (dip and spray) on PAT deposition. A solvent mixture of 75:25 v/v Et-OH:DMSO was determined to be the best for obtaining smooth and homogenous PAT coating. PAT coated stents prepared using 8 mg/mL and 3 mg/mL concentrations of PAT by dip and spray coating methods, respectively, were optimal in terms of carrying adequate drug doses (0.35 µg/mm(2) for dipping and 0.76 µg/mm(2) for spraying) as well as negligible defects observed in the coating. PAT was successfully released from SAMs coated stents in a biphasic manner with an initial burst followed by a sustained release for up to 10 weeks. Thus, this study sheds light on the effects of solvents, drug concentrations, and coating methods on preparing a polymer-free DES. PMID:24705673
Determination of optimal self-drive tourism route using the orienteering problem method
NASA Astrophysics Data System (ADS)
Hashim, Zakiah; Ismail, Wan Rosmanira; Ahmad, Norfaieqah
2013-04-01
This paper was conducted to determine the optimal travel routes for self-drive tourism based on the allocation of time and expense by maximizing the amount of attraction scores assigned to each city involved. Self-drive tourism represents a type of tourism where tourists hire or travel by their own vehicle. It only involves a tourist destination which can be linked with a network of roads. Normally, the traveling salesman problem (TSP) and multiple traveling salesman problems (MTSP) method were used in the minimization problem such as determination the shortest time or distance traveled. This paper involved an alternative approach for maximization method which is maximize the attraction scores and tested on tourism data for ten cities in Kedah. A set of priority scores are used to set the attraction score at each city. The classical approach of the orienteering problem was used to determine the optimal travel route. This approach is extended to the team orienteering problem and the two methods were compared. These two models have been solved by using LINGO12.0 software. The results indicate that the model involving the team orienteering problem provides a more appropriate solution compared to the orienteering problem model.
Xie, Lie-Jun; Zhou, Cai-Lian; Xu, Song
2016-01-01
In this work, an effective numerical method is developed to solve a class of singular boundary value problems arising in various physical models by using the improved differential transform method (IDTM). The IDTM applies the Adomian polynomials to handle the differential transforms of the nonlinearities arising in the given differential equation. The relation between the Adomian polynomials of those nonlinear functions and the coefficients of unknown truncated series solution is given by a simple formula, through which one can easily deduce the approximate solution which takes the form of a convergent series. An upper bound for the estimation of approximate error is presented. Several physical problems are discussed as illustrative examples to testify the validity and applicability of the proposed method. Comparisons are made between the present method and the other existing methods. PMID:27462514
A validated SPME-GC-MS method for simultaneous quantification of club drugs in human urine.
Brown, Stacy D; Rhodes, Daniel J; Pritchard, Boyd J
2007-09-13
A solid-phase microextraction-gas chromatographic-mass spectrometric (SPME-GC-MS) method has been developed and validated for measuring four club drugs in human urine. These drugs include gamma-hydroxybutyrate (GHB), ketamine (KET), methamphetamine (MAMP), and methylenedioxymethamphetamine (MDMA). These drugs are referred to as 'club drugs' because of their prevalence at parties and raves. Deuterium labeled internal standards for each of the four drugs was included in the assay to aid in quantitation. The drugs were spiked into human urine and derivatized using pyridine and hexylchloroformate to make them suitable for GC-MS analysis. The SPME conditions of extraction time/temperature and desorption time/temperature were optimized to yield the highest peak area for each of the four drugs. The final SPME parameters included a 90 degrees C extraction for 20min with a 1min desorption in the GC injector at 225 degrees C using a splitless injection. All SPME work was done using a 100microm PDMS fiber by Supelco. The ratio of pyridine to hexylchloroformate for derivatization was also optimized. The GC separation was carried out on a VF-5ht column by Varian (30m, 0.25mm i.d., 0.10microm film thickness) using a temperature program of 150-270 degrees C at 10 degrees C/min. The instrument used was a ThermoFinnigan Trace GC-Polaris Q interfaced with a LEAP CombiPal autosampler. The data was collected by using extracted ion chromatograms of marker m/z values for each drug from the total ion chromatograms (TIC) (full scan mode). Calibration curves with R(2)>0.99 were generated each day using the peak area ratios (peak area drug/peak area internal standard) versus concentration. The validated method resulted in intra-day and inter-day precision (% R.S.D.) of less than 15% and a % error of less than 15% for four concentrations in the range of 0.05-20microg/mL (MAMP) and 0.10-20microg/mL (GHB, KET, and MDMA). This method has the advantage of an easy sample preparation with
Wright, A.; McCoy, A.; Henkin, S.; Flaherty, M.; Sittig, D.
2013-01-01
Background In a prior study, we developed methods for automatically identifying associations between medications and problems using association rule mining on a large clinical data warehouse and validated these methods at a single site which used a self-developed electronic health record. Objective To demonstrate the generalizability of these methods by validating them at an external site. Methods We received data on medications and problems for 263,597 patients from the University of Texas Health Science Center at Houston Faculty Practice, an ambulatory practice that uses the Allscripts Enterprise commercial electronic health record product. We then conducted association rule mining to identify associated pairs of medications and problems and characterized these associations with five measures of interestingness: support, confidence, chi-square, interest and conviction and compared the top-ranked pairs to a gold standard. Results 25,088 medication-problem pairs were identified that exceeded our confidence and support thresholds. An analysis of the top 500 pairs according to each measure of interestingness showed a high degree of accuracy for highly-ranked pairs. Conclusion The same technique was successfully employed at the University of Texas and accuracy was comparable to our previous results. Top associations included many medications that are highly specific for a particular problem as well as a large number of common, accurate medication-problem pairs that reflect practice patterns. PMID:23650491