SEARCH · Search PubMed

Results for “Problem Formulation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,657 records · Page 92Linked to original sources

PubMedDate not supplied

[From Vostok to Mir: psychological aspects].

Based on achievements in clinical medicine, medical expertise of the flying personnel, ergonomics, human engineering and other life sciences, as well as on the experience gained by Intercosmos researchers, space psychology transformed during 1960-1988 into an independent scientific discipline. This new branch of science has the capability to formulate and resolve important theoretical and applied problems of crew selection and training, assessment of emotional status and work capacity, prevention and optimization of crew activities. The findings and observations made it possible for space psychology to develop psychological reliability criteria and consequently to maintain good mental health and high work capacity of crewmembers in long-term space missions.

Adaptation, Psychological↗

PubMed1980

Child abuse intervention: conflicts in current practice and legal theory.

Recent litigation of child abuse cases indicates that two contradictory policies compete for court approval. One policy would reduce the amount of intervention into abusive families on grounds of privacy. The other seeks to maintain and expand channels of investigation and treatment. While attempting to prescribe a comprehensive approach to child abuse, these conflicting policies, in fact, address different problems in child protection. Without a treatment formulation that focuses on the separate issues raised by each policy, it is not clear that clinicians will be able to sustain child abuse investigatory and protective authority against the privacy attack. This treatment synthesis must entail development of standards that maximize protection of the child from caretakers at the earliest stages of risk and protection from administrative procrastination in case resolution. Protecting the child rather than the family institution should provide the central focus of policy formulation.

Child↗

PubMedDate not supplied

Addiction and paranoid process: psychoanalytic perspectives.

Multiple aspects of the problem of drug abuse and addiction are formulated in terms of the dynamics of the paranoid process, specifically emphasizing the complex interactions of introjection, projection, and the paranoid construction. The effect of projection is to modify the experience of the drug substance so qualities and capacities, often powerful and magical, are attributed to it, allowing it to serve as an external agency contributing to the maintenance of internal introjective configurations and correspondingly to the preservation of an inner sense of self-cohesion. The projective dynamics deal primarily with the vicissitudes of aggression and narcissism, and are given a sense of organization and meaningful integration by the cognitive elaboration of the paranoid construction. They also serve to locate the drug-taking behavior in a larger matrix of familial, social, and other environmental influences, which tend to give support to the projective system. The interaction of these projective psychological dynamics with the pharmacological action of drug substances completes the drug equation and helps to shed further light on the selection of specific drug substances as having addictive potential.

Adult↗

PubMed1994

New concepts in high tibial osteotomy for medial compartment osteoarthritis.

Medial compartment osteoarthritis remains a clinical challenge for the orthopedic surgeon. Accurate preoperative planning is an integral part of management. MCOA with genu varum is not a single condition but a family of related deformities. One single technique may not be appropriate for all the permutations. An individualized approach is necessary to address the many facets of this complex disorder. Treatment must begin with recognition of all of these facets through careful history and physical examination and radiographic evaluation and through preoperative planning of the location of the deformity (femur, tibia, or knee joint), level of angulation, magnitude of the deformity, and plane of the angulation. One can then formulate a treatment plan to address the problems identified. Surgeons should not become rigid in their choice of method or device, but also consider its appropriateness to address the problems to be corrected. Because the patient seeks to prolong the life of the knee before joint replacement, a comprehensive approach achieving as accurate a correction as possible should be associated with the best possible outcome. In total knee replacement, the important emphasis has been on achieving correct bony alignment and soft-tissue balance. With osteotomy, the emphasis has been on bony alignment. However, soft-tissue balance should also be considered an important element in preserving the knee in osteotomy surgery.

Bone Malalignment↗

PubMed1997

[The effect of controlled release of DOPA and carbidopa on clinical response and plasma pharmacokinetics of DOPA in parkinsonian patients].

This is a multicentric double blind comparison of the effects of standard and slow release levodopa + carbidopa formulations in patients with Parkinson's disease. Sixty four patients with simple fluctuations were included and 43 finished the study. The study had three phases: a) optimal dose findings phase with standard levodopa + carbidopa; b) open label, cross over study with the two formulations, and c) double blind, parallel investigation. The following results were obtained. There was not a difference in the severity of disability according to UPDRS, part 3, scores though the subjective impressions of patients were in favor of standard formulations. The Sustained release levodopa + carbidopa produced significant improvement of dystonia in off period, pain due to akinesia in off and the number of hours in off and the quality and latency of sleep. In addition there was a tendency in favor of slow release compounds for early morning akinesia, global effect and impression of the examining physician. Low protein diet improved the kinetics of levodopa and the clinical response with both formulations. The clinical usefulness of standard and slow release levodopa + carbidopa formulation should be weighted according to individual problems of patients with Parkinson's disease.

Age of Onset↗

PubMedDate not supplied

[The problems of the experimental and clinical pharmacology of venotropic drugs].

The article deals with problems of phenomenology of the selective vasomotor response of veins to the effect of drugs, analyses the peripheral and central hemodynamic effects of venotropic drugs, discusses and systematizes the principles of correct quantitative evaluation of venomotor reactions. Some representatives of the group of venotropic drugs are characterized and the main problems of their clinical use are discussed. The problems of promising trends of research are formulated.

Animals↗

PubMed1998

Correlation of intestinal structure and function in HIV infection.

The gastrointestinal tract has great importance in HIV infection because of its role as a primary barrier to the external environment and consequent need for effective immune function. Many factors promote the development of diarrhea in HIV-infected individuals. Understanding the genesis of the symptom is key to formulating effective therapy. Ultimate control of the problem depends on preventing HIV replication and immune depletion, as well as avoiding the development of opportunistic enteric infections in patients with severe immune deficiency.

AIDS-Related Opportunistic Infections↗

PubMed2006

Excipient quantitation and drug distribution during formulation optimization.

An oral granules formulation experienced high drug content and increased variability when the process was scaled up from lab scale to clinical manufacturing scale. It was suspected that mannitol, due to its smaller particle size and lower density, was preferentially lost during the top spray granulation process, thereby causing active enrichment in the remaining granules. In order to troubleshoot the problem, rapidly evaluate solutions, and further optimize the formulation, a simple and rapid analytical technique was required. Since mannitol does not have a UV chromophore, conventional HPLC/UV analysis could not be used. Three alternative analytical techniques were evaluated in terms of ease of use, reproducibility, linear dynamic range and rapidity. The HPLC/RID (refractive index detector) and HPLC/ELSD (evaporative light scattering detector) provided rapid, reproducible alternate techniques to HPLC/UV, whereas LC/MS showed poor reproducibility. Analysis of the sieve samples of the granulations by HPLC/RID and HPLC/ELSD confirmed that poor active drug distribution was due to mannitol losses in the filter bag, as well as increased low size granules low in active drug content. The resultant formulation process was modified and a reduction in the initial air flow at start-up reduced losses of mannitol in the granulator filters.

Chemistry, Pharmaceutical↗

PubMed2006

Identification of metabolic system parameters using global optimization methods.

BACKGROUND: The problem of estimating the parameters of dynamic models of complex biological systems from time series data is becoming increasingly important. METHODS AND RESULTS: Particular consideration is given to metabolic systems that are formulated as Generalized Mass Action (GMA) models. The estimation problem is posed as a global optimization task, for which novel techniques can be applied to determine the best set of parameter values given the measured responses of the biological system. The challenge is that this task is nonconvex. Nonetheless, deterministic optimization techniques can be used to find a global solution that best reconciles the model parameters and measurements. Specifically, the paper employs branch-and-bound principles to identify the best set of model parameters from observed time course data and illustrates this method with an existing model of the fermentation pathway in Saccharomyces cerevisiae. This is a relatively simple yet representative system with five dependent states and a total of 19 unknown parameters of which the values are to be determined. CONCLUSION: The efficacy of the branch-and-reduce algorithm is illustrated by the S. cerevisiae example. The method described in this paper is likely to be widely applicable in the dynamic modeling of metabolic networks.

Algorithms↗

PubMed2002

Use of critical interactive thinking exercises in teaching reproductive physiology to undergraduate students.

In higher education, increasing emphasis is being placed on the use of new technologies in the classroom. However, the emphasis needs to be placed on methods that truly enhance understanding and knowledge retention. Class discussions help students understand and retain information previously presented in lecture format. Furthermore, if students are challenged to critically evaluate, communicate, and defend their ideas, knowledge retention and understanding will increase even more. Critical interactive thinking exercises (CITE) were employed at two different universities to enhance student knowledge retention and promote the development of critical thinking. Applicability of CITE to undergraduate learning was assessed over a 3-yr period in the undergraduate reproductive physiology courses at Michigan State University and the University of Missouri-Columbia. For each exercise, students were challenged to prepare a one-page, double-spaced composition addressing an incompletely understood phenomenon or problem-solving situation related to the reproductive system. In preparing their compositions, students were encouraged to use information previously presented in lecture plus outside information to develop their ideas. Students were required to formulate and defend a hypothesis or approach to the problem presented. At the subsequent class period, students were divided into groups of three to four, in which they interactively discussed their ideas. Each group member was challenged to defend his or her hypothesis and explanation and to persuade other group members to adopt their ideas. Each group then arrived at a consensual opinion that was presented during a discussion by the entire class. The class then debated the merits of each group's hypothesis or explanation and the supporting arguments presented. At first, the students were apprehensive about the CITE, particularly about communicating and defending ideas with their classmates. However, course evaluations showed that 131 out of 137 students considered the CITE a positive experience that enhanced learning. Additionally, 131 out of 137 students reported that the CITE enhanced their critical thinking skills. We feel that the use of CITE in teaching reproductive theory to undergraduate students fosters critical thinking skills, communication skills, and knowledge retention. The general concept can be readily applied to courses in other subject areas in the animal sciences.

Animal Husbandry↗

PubMed2001

[Stages and results of Epidemiology Department activities].

The paper sums up the activities of Department of Epidemiology of Medical Prophylaxis Faculty, I. M. Setchenov Moscow Medical Academy, in the 70 years of its existence. The Department plays the leading role in training specialists for sanitary and epidemiological service of the country. The main research, training, and methodological works in this speciality were prepared by the Department staff members, who prepared curricula for pre- and postgraduate training. For many years the department has been the methodological center in epidemiology training. Trends of research at the Department are concentrated on the pressing problems of general and special epidemiology. Due to activities of the department staff, epidemiological aspects have been studied and fundamentals of prevention and liquidation of many infectious diseases in the country have been formulated: enteric and streptococcal infections, typhus, tularemia, diphtheria, etc. Problems of epidemiological geography, including nosogeography, territorial and republican epidemiology have been investigated. Functioning of parasitic systems and mechanisms of epidemic process in some infections have been characterized with due regard for modern theoretical, methodological, and organization base of epidemiology. The data were used for developing new basis and organization forms of epidemiological surveillance of infectious diseases.

Academies and Institutes↗

PubMed1998

Analytical validation of the BEM--application of the BEM to the electrocardiographic forward and inverse problem.

The objective of this study is to analytically validate a boundary element (BE) formulation for the relationship between the transmembrane potential on the heart's surface and the potential on the body surface applying a concentric spherical test geometry. The relative difference (reldif) between the potential on the outer sphere of the test geometry computed analytically and numerically is determined by 3.59% for the coarse discretization (48 BEs) and by 0.46% in the case of the finer subdivision (192 BEs). In the inverse problem, the transmembrane potential on the inner sphere is estimated numerically from the electric potential on the outer sphere by using a minimum-norm least-square approach. The relative differences found are 20.2% when no measurement noise is added and 26.4% in the presence of 2% additional Gaussian noise. The BE formulation is also applied to real world data for solving the electrocardiographic inverse problem. A normal volunteer's inhomogeneous thorax (outer thorax surface, surfaces of the lungs, epicardial heart surface) is modelled by 424 BEs. The same inverse method is then applied in order to reconstruct the transmembrane potential on the epicardium from the measured body surface potential (BSP) data during normal ventricular depolarisation.

Electrocardiography↗

PubMed2002

Source-detector calibration in three-dimensional Bayesian optical diffusion tomography.

Optical diffusion tomography is a method for reconstructing three-dimensional optical properties from light that passes through a highly scattering medium. Computing reconstructions from such data requires the solution of a nonlinear inverse problem. The situation is further complicated by the fact that while reconstruction algorithms typically assume exact knowledge of the optical source and detector coupling coefficients, these coupling coefficients are generally not available in practical measurement systems. A new method for estimating these unknown coupling coefficients in the three-dimensional reconstruction process is described. The joint problem of coefficient estimation and three-dimensional reconstruction is formulated in a Bayesian framework, and the resulting estimates are computed by using a variation of iterative coordinate descent optimization that is adapted for this problem. Simulations show that this approach is an accurate and efficient method for simultaneous reconstruction of absorption and diffusion coefficients as well as the coupling coefficients. A simple experimental result validates the approach.

Bayes Theorem↗

PubMed1995

Variation in the association of alcohol consumption with five DSM-IV alcohol problem domains.

Data from a nationally representative sample of the U.S. adult population were used to investigate the association between alcohol consumption and five discrete problem domains included in the DSM-IV formulations for alcohol abuse and dependence. Two dimensions of consumption were considered in the analysis: average daily ethanol intake and the relative frequency of drinking five or more drinks. The sample consisted of 22,102 adults defined as current drinkers. After controlling for various sociodemographic characteristics, family history of alcoholism, and age at onset of drinking, both consumption measures retained significant levels of association within all five problem domains. The magnitudes of the odds ratios at selected levels of consumption were approximately 50% greater for the domains of impaired control, continued drinking despite problems and hazardous drinking than for the domains of tolerance and withdrawal. Moreover, the factors that modified the effect of the consumption measures varied markedly across domains, with age, college education, and race the most consistent modifiers of the effect of alcohol consumption.

Adolescent↗

PubMed2000

A bidomain model based BEM-FEM coupling formulation for anisotropic cardiac tissue.

A hybrid boundary element method (BEM)/finite element method (FEM) approach is proposed in order to properly consider the anisotropic properties of the cardiac muscle in the magneto- and electrocardiographic forward problem. Within the anisotropic myocardium a bidomain model based FEM formulation is applied. In the surrounding isotropic volume conductor the BEM is adopted. Coupling is enabled by requesting continuity of the electric potential and the normal of the current density across the boundary of the heart. Here, the BEM part is coupled as an equivalent finite element to the finite element stiffness matrix, thus preserving in part its sparse property. First, continuous convergence of the coupling scheme is shown for a spherical model comparing the computed results to an analytic reference solution. Then, the method is extended to the depolarization phase in a fibrous model of a dog ventricle. A precomputed activation sequence obtained using a fine mesh of the heart was downsampled and used to calculate body surface potentials and extracorporal magnetic fields considering the anisotropic bidomain conductivities. Results are compared to those obtained by neglecting in part or totally (oblique or uniform dipole layer model) anisotropic properties. The relatively large errors computed indicate that the cardiac muscle is one of the major torso inhomogeneities.

Animals↗

PubMed1979

Analysis of patient states and state transitions.

Psychiatric diagnoses and formulations have classically focused on the chief complaint of the patient as part of a larger pattern of episodes and reactions. This is a form of state analysis in which the problem states of a person are carefully described and distinguished from other states. The authors suggest methods for deepening such formulations by grounding description of problem states in models of other states and models of state transitions. The resultant method of state analysis can be applied to examination of change processes during treatment as well as to initial diagnostic formulations. As an example of its use and possible extension to quantification, state analysis is applied to description of status and change in a person treated by brief psychotherapy. Because state analysis is based on observable behavior and reportable conscious experiences, it serves as a useful beginning point upon which to anchor more extended inferences about psychodynamics.

Emotions↗

PubMed2001

Quality of student-generated learning issues in a problem-based curriculum.

In a problem-based curriculum students generate learning issues that are the guidelines for their individual study. In an earlier study it was found that a useful learning issue contains a keyword that demarcates the content of a certain topic to be studied and is formulated concisely and unambiguously for all members of the tutorial group. This study investigates two questions. First, how many learning issues can be classified as being of good or bad quality as evaluated against three criteria? Second, what are examples of well and badly formulated learning issues? Learning issues were collected for two problems in the first year during two tutorial meetings of the Maastricht Medical School in the academic year 1998-99. In the next academic year, 12 first year-students were asked to judge the learning issues for each problem against three criteria. The results showed that 21% of the learning issues for one problem and 32% for the other problem were classified as scoring high on all three characteristics. A very small percentage of learning issues (5% and 2%) were classified as scoring low on all three characteristics. Most learning issues scored differently on each of the characteristics. Although most learning issues contain a keyword, many of them were formulated ambiguously and not concisely. It is concluded that first-year students are not yet able to formulate clear learning issues.

Journal Article↗

PubMed2004

The modulated oral fluoropyrimidine prodrug S-1, and its use in gastrointestinal cancer and other solid tumors.

The fluoropyrimidine anticancer agent 5-fluorouracil (5-FU) is active in a wide range of solid tumors, particularly gastric, colorectal, and head and neck cancers. Whilst infusional 5-FU is associated with higher response rates and a favorable safety profile as compared to the classical i.v. bolus administration, prolonged infusions can be inconvenient for the patients and catheter-related problems are common complications. An oral 5-FU formulation would allow for sustained 5-FU plasma concentrations, mimicking the pharmacokinetics (PK) of a continuous infusion with the addition of convenience of administration. The oral administration of 5-FU itself is not feasible due to the high activity of dihydropyrimidine dehydrogenase in the gut wall, which causes rapid metabolism of the drug, and results in decreased and erratic absorption of 5-FU and non-linear PK. To bypass this problem, oral fluoropyrimidine derivatives were developed either in the form of 5-FU prodrugs (i.e. tegafur, doxifluridine or capecitabine), or as enzyme inhibitors (i.e. eniluracil) administered with 5-FU, or as both prodrugs and enzyme inhibitors (i.e. S-1, UFT or BOF-A2). This review will focus on the oral fluoropyrimidine S-1, which consists of the 5-FU prodrug tegafur (ftorafur, FT) and two enzyme inhibitors, i.e. CDHP (5-chloro-2,4-dihydroxypyridine) and OXO (potassium oxonate), in a molar ratio of 1(FT):0.4 (CDHP):1(OXO). Phase II trials have demonstrated that S-1, as a single agent, is active for the treatment of gastric, colorectal, head and neck, breast, non-small cell lung, and pancreatic cancers. Phase III trials are currently underway in gastric cancer and these results are awaited to confirm the phase II findings. Furthermore, the combination of S-1 with cisplatin (CDDP), irinotecan or docetaxel for the treatment of gastric cancer and with CDDP for non-small cell and pancreatic cancer is feasible and active. The activity observed with S-1 in the phase II studies is at least equivalent, if not better, than continuous i.v. and bolus 5-FU and the other oral fluoropyrimidines. Thus, we may finally be seeing the realization of oral treatments for the management of various solid tumors and could be on the brink of a new approach to treatment strategies.

Administration, Oral↗