Search PubMed⌕ Search

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.

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

At least 1,711 records · Page 95Linked to original sources
PubMed1994

[Consensus conference. Saving blood: which are still the doubts and the problems?].

The consensus conference on blood saving has allowed us to formulate some interesting guidelines. The autologous and homologous transfusion require the patient's consent. For volemic replacement crystalloid solutions are used for phlebotomies below 10-15%, and colloid solutions for those greater than 10-15% of the blood mass. Severe isovolemic hemodilution (Ht < 20%) necessitates the reduction of the dosage of some drugs. A limit of Hb around 9 g/dl after phlebotomy may be acceptable in the absence of cerebral and coronary vascular disease. Phlebotomies are therefore possible also when the Hb values are 10 g/dl (Ht 30%). Hb values around 7 g/dl in the late postoperative period (from day 3 to 6) may be accepted only if well tolerated. The blood salvaged during surgery and at the beginning of the postoperative phase must always be centrifugated, washed and microfiltered. Subsequently, in the first 8 hours it is possible to reinfuse red cells after sedimentation and microfiltration. The techniques of predeposit, hemodilution and recovery are valid especially if associated with careful control of postoperative bleeding by means of aspiration under controlled pressure (at minimum negative values and sometimes positive ones), monitoring of blood loss from drainage and application of elastic compression bandages.

Blood Loss, Surgical↗
PubMed2000

Continuous topical administration of a petrolatum formulation by a novel disposable diaper. 2. Effect on skin condition.

BACKGROUND: Diaper dermatitis is a common childhood affliction. Aiming to help reduce the prevalence of this problem, we have developed a novel diaper to deliver to the skin dermatological formulations intended to help protect the skin from overhydration and irritation. OBJECTIVE: To determine the clinical benefits of a novel disposable diaper designed to deliver a petrolatum-based formulation continuously to the skin during use. METHODS: Two independent, blinded, randomized clinical trials were conducted, involving an aggregate total of 391 children, 8-24 months of age. All comparisons were done versus a control diaper, identical to the test product except for the absence of the petrolatum formulation. The studies determined the effects of the novel diaper on skin erythema and diaper rash. RESULTS: Use of the formulation-treated diaper was associated with significant reductions in severity of erythema and diaper rash compared to the control product. CONCLUSIONS: The results demonstrated the clinical benefits associated with continuous topical administration of a petrolatum-based formulation by this novel diaper. We anticipate that this advance in diaper design will contribute significantly to further reduce the prevalence and severity of irritant contact dermatitis in the diaper area.

Administration, Topical↗
PubMed1990

Pharmacokinetics of gestagens: some problems.

Various approaches to studying the pharmacokinetics of gestagens and the factors that influence derivation of the parameters are described with levonorgestrel used as an example. Published studies of the pharmacokinetics of levonorgestrel are reviewed, and new information is presented regarding intra- and intersubject variation. Differences between various formulations of levonorgestrel are apparent when the formulations are compared in the same subjects. There is also a marked difference in the parameters when derived under single-dose or steady-state conditions. The role of sex hormone-binding globulin in the metabolism of levonorgestrel is questioned. Large intra- and inter-subject variations in the parameters exist, and a subject may show a large month-to-month variation when one levonorgestrel formulation is used and smaller variations when another formulation is used. This wide variability in the pharmacokinetic parameters, problems that arise in the derivation and interpretation of the parameters, the biologic significance of most of these parameters, and their lack of correlation with pharmacodynamic responses severely limit the usefulness of pharmacokinetic studies of the gestagens.

Biological Availability↗
PubMed2005

The wording of conclusions in relational reasoning.

Literature on relational reasoning mainly focuses on the performance question. It is typically argued that problem difficulty relies on the number of "mental models" compatible with the problem. However, no study has ever investigated the wording of conclusions that participants formulate. In the present work, we analyze the relational terms that people use in drawing conclusions from spatial relation problems (A is to the left of B, B is to the left C, D is in front of A, E is in front C, What is the relation between D and E?). We observed a general preference for expressing conclusions with 'left' rather than conclusions with 'right'. We also found that three factors had an influence on the wording of the conclusions: the linguistic form of premises, the question type and the presentation format. On the other hand, the number of models and premise order did not affect the wording of conclusions. Our study shows that the type of conclusion produced provides a new key to identifying the mental processes involved in spatial reasoning. Implications for the two main approaches to reasoning processes (i.e. the analogical and the propositional approaches) are discussed.

Child↗
PubMed1993

Novel Taxol formulations: Taxol-containing liposomes.

Taxol is a complex diterpenoid natural product under investigation for therapy of colon, ovarian, lung, and breast cancer, as well as for melanoma and lymphoma. One problem associated with the administration of Taxol is its low solubility; the formulation used clinically contains polyethoxylated castor oil (Cremophor EL) and ethanol as excipients. Cremophor EL is implicated in hypersensitivity reactions observed on infusion of Taxol. To eliminate the Cremophor EL vehicle and possibly improve the antitumor efficacy of Taxol, a systematic approach was taken to formulate Taxol in phospholipid suspensions (liposomes). Prototype formulations were developed that have sufficient chemical and physical stability to test the hypothesis that liposomes can alter the pharmacology of Taxol, in addition to providing a biologically compatible carrier in which to administer the drug. In vitro. Taxol liposomes retain the growth-inhibitory activity of free Taxol against a variety of tumor cell lines. In vivo, preliminary results showed no effect of free Taxol (in Cremophor EL) on the growth of Colon-26, a Taxol-resistant murine tumor, when given at doses that included or exceeded the maximum tolerated dose (MTD). In contrast, Taxol liposomes delayed tumor progression at a dose that exceeded the MTD of free Taxol.

Animals↗
PubMed1992

[A new inclusion complex of silibinin and beta-cyclodextrins: in vitro dissolution kinetics and in vivo absorption in comparison with traditional formulations].

The very low bioavailability of silybinin, the main constituent of silymarin, so far prevented the development of an oral pharmaceutical specialty based on this active ingredient. To overcome this difficulty, an inclusion complex between Silybinin and beta-Cyclodextrin was prepared. The new complex was compared in vitro tests (dissolution rate) and in a in vivo test (rat bile elimination) with silybinin, silymarin and one traditional formulation based on silybinin. The results show a dramatic increase in the dissolution rate of the complex (> 90% within 5 min) respect to the silybinin that confirm to be practically insoluble (< 5%). The in vivo results agree with the dissolution rates; after administration of the silybinin complex p.o., the silybinin concentration in the rat bile was near 20 times more than after administration of silybinin as is or in a traditional formulation. In the last two cases, the silybinin concentration was even 6 times less than after administration of the same amount of silymarin. These data show that the beta-CD complex solved the problem of the bioavailability of silybinin which, in the traditional formulation utilised as reference, proved to be not bioavailable.

Absorption↗
PubMed2003

Meshfree representation and computation: applications to cardiac motion analysis.

For medical image analysis issues where the domain mappings between images involve large geometrical shape changes, such as the cases of nonrigid motion recovery and inter-object image registration, the finite element methods exhibit considerable loss of accuracy when the elements in the mesh become extremely skewed or compressed. Therefore, algorithmically difficult and computationally expensive remeshing procedures must be performed in order to alleviate the problem. We present a general representation and computation framework which is purely based on the sampling nodal points and does not require the construction of mesh structure of the analysis domain. This meshfree strategy can more naturally handle very large object deformation and domain discontinuity problems. Because of its intrinsic h-p adaptivity, the meshfree framework can achieve desired numerical accuracy through adaptive node and polynomial shape function refinement with minimum extra computational expense. We focus on one of the more robust meshfree efforts, the element free Galerkin method, through the moving least square approximation and the Galerkin weak form formulation, and demonstrate its relevancy to medical image analysis problems. Specifically, we show the results of applying this strategy to physically motivated multiframe motion analysis, using synthetic data for accuracy assessment and for comparison to finite element results, and using canine magnetic resonance tagging and phase contrast images for cardiac kinematics recovery.

Algorithms↗
PubMed1991

8-Methoxypsoralen serum levels in poor responders to photochemotherapy. Importance of drug formulation and individual factors.

8-Methoxypsoralen (8-MOP) serum levels of psoriatic patients poorly responsive to photochemotherapy (PUVA) treatment (problem cases) were determined by the HPLC method with 11 single blood probes over 8 hours. Abnormally low or deviated serum levels were found in 7 of 11 PUVA problem patients. There was a great interindividually different first-pass effect for 8-MOP in dependence on the galenic formulation of the 8-MOP brand; therefore, the change to another 8-MOP brand with a modern galenic formulation led only to a slight increase of serum levels, and consequently an increase in the 8-MOP dosage was necessary. It is important to be cautious at this point because patients may show an unproportional increase of 8-MOP serum levels due to the individually limited capacity of biotransformation. The studies of the authors reaffirm the necessity of the determination of 8-MOP serum levels in problem cases of PUVA therapy.

Biological Availability↗
PubMed2006

"What the patient would have decided": a fundamental problem with the substituted judgment standard.

Decision making for incompetent patients is a much-discussed topic in bioethics. According to one influential decision making standard, the substituted judgment standard, the decision that ought to be made for the incompetent patient is the decision the patient would have made, had he or she been competent. Although the merits of this standard have been extensively debated, some important issues have not been sufficiently explored. One fundamental problem is that the substituted judgment standard, as commonly formulated, is indeterminate in content and thus offers the surrogate little or no guidance. What the standard does not specify is just how competent one should imagine the patient to be, and what else one ought to envision about the patient's hypothetical outlook and the circumstances surrounding his or her decision making. The article discusses this problem of underdetermined decision conditions.

Decision Making↗
PubMed2006

Nanoparticles of poly(lactide)/vitamin E TPGS copolymer for cancer chemotherapy: synthesis, formulation, characterization and in vitro drug release.

Paclitaxel is one of the best anticancer drugs, which has excellent therapeutic effects against a wide spectrum of cancers. The formulation of paclitaxel used in its currently clinical administration includes Cremophor EL, which has been found to cause serious side effects. Nanoparticle formulation of paclitaxel may provide an ideal solution for this problem and achieve a sustained chemotherapy. A novel copolymer, poly(lactide)-vitamin E TPGS (PLA-TPGS), was synthesized from lactide and d-alpha-tocopheryl polyethylene glycol 1000 succinate by bulk polymerization for nanoparticle formulation of anticancer drugs. 1H NMR, FTIR and GPC were used to detect molecular structure of the copolymer. Paclitaxel-loaded PLA-TPGS nanoparticles were fabricated by a modified solvent extraction/evaporation technique with or without emulsifier involved, which were characterized by laser light scattering for size and size distribution; field emission scanning electron microscopy for surface morphology; zeta potential for surface charge; X-ray photoelectron spectroscopy for surface chemistry. The drug encapsulation efficiency and the in vitro drug release kinetics were measured by high-performance liquid chromatography. Formulation optimization was pursued. The particles were found of around 300 nm in size and narrow size distribution. Of all, 89% drug encapsulation efficiency has been achieved for nanoparticles of 5% drug loading. The drug release from PLA-TPGS nanoparticles was found to be biphasic with an initial burst of 17% in the first day, followed by a sustained pattern with 51% release after 31 days.

Antineoplastic Agents, Phytogenic↗
PubMed2000

[Sexual problems experienced by women in HIV-1 crisis].

This descriptive study was based on the assumptions of qualitative investigation methods and on the Crisis Theory formulated by CAPLAN (1966). The objective of the study was to identify the sexual problems experienced by women undergoing an HIV-1 crisis. Data were collected through a semi-structured interview recorded by the method of FREITAS et al. (1992) and analyzed by the method of MEIHY (1996). Authors concluded that these women maintained themselves unbalanced using negative coping mechanisms. Thus, authors believe that it would be possible to help them using adequate nursing actions such as educational and guidance actions, but mainly by actions directed to the needs of patients undergoing an HIV-1 crisis.

Adaptation, Psychological↗
PubMed2004

Solution of low-dimensional constrained model predictive control problems.

Large benefits are possible by utilizing the solution of the constrained optimization problem involved in model predictive control. For a special case of these problems, the solution can be obtained relatively easily from its relationship with the unconstrained optimum. In this paper, a visualization of the relationship between the constrained and unconstrained optimum is presented. Based upon this relationship, a method for finding the constrained optimum is proposed that is suitable for low-dimensional control systems. A comparison with a linear programming formulation on 2 x 2 and 3 x 3 problems shows that the computational effort can be 10-35 times lower. For such processes, the proposed approach may allow one to avail the benefits of optimization by using the small process control systems already present in many plants.

Journal Article↗
PubMed2005

In vivo evaluation of nicotine lyophilised nasal insert in sheep.

The nasal route offers an attractive means of delivering a drug directly to the systemic circulation and avoiding hepatic first-pass metabolism, although rapid mucociliary clearance can be detrimental to nasal absorption. The in vitro and in vivo characteristics of a nasal insert formulation prepared by lyophilisation of a viscous HPMC gel solution designed to overcome this problem were studied. In vitro release of nicotine from the lyophilised insert was compared with powder and spray formulations. Stability and characterisation studies were carried out using dynamic vapour sorption, scanning electron microscopy and HPLC analysis. Nicotine formulations were administered to eight wether sheep in a randomised four-way cross-over study, and plasma nicotine assessed comparing the nasal insert formulation with conventional nasal powder, nasal spray and IV doses. In vitro release studies demonstrated prolonged nicotine release from the nasal insert formulation compared to a powder and liquid. In vivo plasma profiles appeared to show prolonged plasma nicotine levels compared to the conventional formulations, although T(max), C(max) and AUC parameters for the insert were not significantly different due to high variability in the pharmacokinetic data. In conclusion, the nasal insert displayed a promising prolonged plasma profile, which must be investigated further to provide statistical significance to prove the effect.

Administration, Intranasal↗
PubMed2003

[Protective care of children in the Czech Republic and the Convention on Children's Rights].

Protective Care of Children is one of the oldest activities aimed at the defence and maintenance of life. It represents a set of actions, activities, and interventions directed to every child, attempting to provide sufficient defence against unfavourable effects on its existence and development. It includes also the knowledge how to prevent them. At the same time attention of workers engaged in the children care is aimed at problems and their solution of developing impairments, disabilities and abnormalities of individual children and the whole child population. It requires an ability to recognize and eliminate endogenous, exogenous or combined adverse effects causing impairments of the children's life. It means treatment and rehabilitation to recover the positive state. The most important role in all such affords have parents and the family. To estimate the level and characteristics of children preventive care in CR, the first (1997) and second (2003) report on evaluation of the Committee on the Rights of the Child and the implementation of the Convention on the Rights of the Child was used. The first evaluation concerned mainly the general problems of children; the second evaluation was focused on individual groups of children in special circumstances. As most important, the Committee found excellent level of health and educational care (though in the second evaluation it found some imperfections in education), the foundation of telephone Childline line for consultation of children in stress and preparation of several laws concerning the family and children. In both evaluations the Committee repeatedly reproached imperfections in the implementation of the most important principles of Covention--the best interest in children, no discrimination, respects to the children's opinion, the right of parents to have children and vice versa, problem of institutionalization. Next problems reproached concerned the not having founded the Coordination organ for the complex protection of child, not having formulated the National plan of care for the family and child, not having solved problem of monitoring, research and education in that field. Though the reproaches of the Committee on the Rights of the Child to our protection of child are not insignificant, the overall view of the Committee and the discussion to the First and Second evaluation are possible to interpret as satisfactory. At the same time, they invite to it next improving, namely considering the basic reproaches and recommendations of the UN Committee on the Rights of the Child.

Child↗
PubMed2004

Potential functionals: dual to density functionals and solution to the v-representability problem.

A functional of external potentials and its variational principle for the ground-state energy is constructed. This potential functional formulation is dual to the density functional approach and provides a solution to the v-representability problem in the original Hohenberg-Kohn theory. A second potential functional for Kohn-Sham noninteracting systems establishes the foundation for the optimized effective potential approach and results in efficient approaches for ensemble Kohn-Sham calculations.

Journal Article↗
PubMed2001

Formulation of entomopathogenic nematode-infected cadavers.

Entomopathogenic nematodes are commercially applied in aqueous suspension. These biocontrol agents may also be applied in nematode-infected insect cadavers, but this approach may entail problems in storage and ease of handling. We determined the feasibility of formulating nematode-infected insect cadavers to overcome these hindrances. All experiments were conducted with Heterorhabditis bacteriophora Poinar and Galleria mellonella (L.). Nonformulated cadavers were used as controls. Of 19 formulations tested (including combinations of starches, flours, clays, etc.) 1 (starch-clay combination) was found to adhere to the cadaver and to have no significant deleterious effects on nematode reproduction and infectivity; other formulations exhibited poor adhesion or reduced nematode reproduction. Two formulations enabled cadavers to be partially desiccated without affecting reproduction; other formulations and nonformulated cadavers exhibited reduced reproduction upon desiccation. Four-day-old cadavers were more amenable to desiccation than 8-day-old cadavers. Formulated cadavers were more resistant to rupturing and sticking together during agitation than nonformulated cadavers.

Animals↗
PubMed1994

Probabilistic inference in computer-aided screening for cervical cancer: an event covering approach to information extraction and decision rule formulation.

A pattern analysis approach called event covering is introduced and applied to the problem of determining the significance of measured morphological attributes of cervical cells in an automated screening process. The approach is shown to be effective in deciding which characteristics at the event (outcome) level are of little or no diagnostic value, and in formulating sets of predictive rules using the most pertinent ones.

Adult↗
PubMed2026

A reinforcement learning-enhanced fuzzy multi-objective equilibrium optimization framework for multiple sequence alignment.

Multiple sequence alignment (MSA) is a fundamental task in bioinformatics, underpinning comparative genomics, structural analysis, and evolutionary inference. However, MSA remains a challenging multi-objective optimization problem due to the need to simultaneously maximize alignment accuracy, preserve conserved regions, and control gap proliferation, particularly in large and heterogeneous sequence collections. In this work, we propose MOFSACEO-MSA, a novel hybrid optimization framework for multiple sequence alignment that integrates a fuzzy multi-objective evaluation scheme with the Equilibrium Optimizer (EO) and a Soft Actor-Critic (SAC)-based adaptive control mechanism. The proposed framework formulates MSA as a dynamic multi-objective optimization problem, in which alignment quality is assessed using complementary residue-level and column-level criteria, including Sum-of-Pairs score, column conservation, entropy, and gap statistics. Fuzzy membership functions are employed to harmonize competing objectives into a unified optimization landscape, while EO provides robust global exploration. To further enhance adaptability, SAC dynamically regulates key EO parameters during the search process, enabling an effective balance between exploration and exploitation across datasets of varying size and heterogeneity. Extensive experiments werew conducted on diverse biological sequence datasets, with a primary focus on RNA benchmarks, including structured families from Rfam, large-scale repositories from RNAcentral and GenBank, and organism-specific tRNA datasets from GtRNAdb. Comparative evaluations against classical alignment tools (ClustalW, MAFFT, MUSCLE, PRANK, KAlign, and T-Coffee), metaheuristic methods (SAGA, Sequoya and EAFSA), and a reinforcement learning-based approach (RLALIGN) demonstrate that MOFSACEO-MSA consistently achieves competitive or superior Sum-of-Pairs scores while significantly reducing gap proportions and maintaining compact alignment lengths. Notably, the proposed framework exhibits improved robustness on large and highly heterogeneous datasets, where existing methods often suffer from excessive gap insertion or unstable convergence. Overall, MOFSACEO-MSA provides a flexible and extensible optimization paradigm that effectively bridges evolutionary search and reinforcement learning for high-quality multiple sequence alignment, with demonstrated effectiveness on challenging RNA alignment tasks.

Sequence Alignment↗