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PubMedDate not supplied

Influence of physical and chemical characteristics of diesel fuels and exhaust emissions on biological effects of particle extracts: a multivariate statistical analysis of ten diesel fuels.

The emission of diesel exhaust particulates is associated with potentially severe biological effects, e.g., cancer. The aim of the present study was to apply multivariate statistical methods to identify factors that affect the biological potency of these exhausts. Ten diesel fuels were analyzed regarding physical and chemical characteristics. Particulate exhaust emissions were sampled after combustion of these fuels on two makes of heavy duty diesel engines. Particle extracts were chemically analyzed and tested for mutagenicity in the Ames test. Also, the potency of the extracts to competitively inhibit the binding of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to the Ah receptor was assessed. Relationships between fuel characteristics and biological effects of the extracts were studied, using partial least squares regression (PLS). The most influential chemical fuel parameters included the contents of sulfur, certain polycyclic aromatic compounds (PAC), and naphthenes. Density and flash point were positively correlated with genotoxic potency. Cetane number and upper distillation curve points were negatively correlated with both mutagenicity and Ah receptor affinity. Between 61% and 70% of the biological response data could be explained by the measured chemical and physical factors of the fuels. By PLS modeling of extract data versus the biological response data, 66% of the genotoxicity could be explained, by 41% of the chemical variation. The most important variables, associated with both mutagenicity and Ah receptor affinity, included 1-nitropyrene, particle bound nitrate, indeno[1,2,3-cd]pyrene, and emitted mass of particles. S9-requiring mutagenicity was highly correlated with certain PAC, whereas S9-independent mutagenicity was better correlated with nitrates and 1-nitropyrene. The emission of sulfates also showed a correlation both with the emission of particles and with the biological effects. The results indicate that fuels with biologically less hazardous potentials should have high cetane number and contain less PAC and sulfur. The results also indicate that engine factors affect the formation and emission of nitrated PAC.

Automobiles↗
PubMed2004

A physical reference state unifies the structure-derived potential of mean force for protein folding and binding.

Extracting knowledge-based statistical potential from known structures of proteins is proved to be a simple, effective method to obtain an approximate free-energy function. However, the different compositions of amino acid residues at the core, the surface, and the binding interface of proteins prohibited the establishment of a unified statistical potential for folding and binding despite the fact that the physical basis of the interaction (water-mediated interaction between amino acids) is the same. Recently, a physical state of ideal gas, rather than a statistically averaged state, has been used as the reference state for extracting the net interaction energy between amino acid residues of monomeric proteins. Here, we find that this monomer-based potential is more accurate than an existing all-atom knowledge-based potential trained with interfacial structures of dimers in distinguishing native complex structures from docking decoys (100% success rate vs. 52% in 21 dimer/trimer decoy sets). It is also more accurate than a recently developed semiphysical empirical free-energy functional enhanced by an orientation-dependent hydrogen-bonding potential in distinguishing native state from Rosetta docking decoys (94% success rate vs. 74% in 31 antibody-antigen and other complexes based on Z score). In addition, the monomer potential achieved a 93% success rate in distinguishing true dimeric interfaces from artificial crystal interfaces. More importantly, without additional parameters, the potential provides an accurate prediction of binding free energy of protein-peptide and protein-protein complexes (a correlation coefficient of 0.87 and a root-mean-square deviation of 1.76 kcal/mol with 69 experimental data points). This work marks a significant step toward a unified knowledge-based potential that quantitatively captures the common physical principle underlying folding and binding. A Web server for academic users, established for the prediction of binding free energy and the energy evaluation of the protein-protein complexes, may be found at http://theory.med.buffalo.edu.

Antigen-Antibody Complex↗
PubMed1999

Accurate linear measurements in the anterior maxilla using orthoradially reformatted spiral computed tomography.

OBJECTIVES: To validate measurement accuracy in proximity to the incisive canal from two-dimensional (2D) reformatted spiral computed tomography (CT). MATERIALS AND METHODS: Eight cadaver heads were examined with spiral CT with 1 mm thick axial slices and 1 mm.s-1 table feed. The data was transferred to a networked computer workstation to generate 2D orthoradially reformatted images. The length of the incisive canal and width of the alveolar crest were measured independently by two oral and maxillofacial radiologists. The soft tissues in the region of the incisive foramen were removed and physical measurements made using an electromagnetic digitizer. RESULTS: There was no statistically significant difference between measurements on orthoradial 2DCT images and physical measurements (P > 0.05). CONCLUSIONS: Accurate measurements for dental implant placement in proximity to the incisive canal can be made from reformatted spiral CT images.

Aged↗
PubMed1984

Instrumentation for positron emission tomography.

Positron emission tomography with a spatial resolution of 2 mm full width at half maximum for quantitation in regions of interest 4 mm in diameter will become possible with the development of detectors that achieve ultrahigh resolution. Improved resolution will be possible using solid-state photodetectors for crystal identification or photomultiplier tubes with many small electron multipliers . Temporal resolution of 2 seconds and gating of cyclic events can be accomplished if statistical requirements are met. The major physical considerations in achieving high-resolution positron emission tomography are the degradation in resolution resulting from positron range, emission angle, parallax error, detector sampling density, the sensitivity of various detector materials and packing schemes, and the trade off between temporal resolution and statistical accuracy. The accuracy of data required for physiological models depends primarily on the fidelity of spatial sampling independent of statistical constraints.

Humans↗
PubMed1995

Physical therapy to improve functioning of older people in residential care facilities.

BACKGROUND AND PURPOSE: The purpose of this study was to determine the effectiveness of an individualized physical therapy mobility training program on the gait, balance, and functional performance of elderly individuals living in residential care facilities. SUBJECTS: Twenty-seven elderly individuals with impaired balance and difficulty performing at least one functional activity participated in the study. The subjects ranged in age from 71 to 97 years (mean = 87.1, SD = 6.7). METHODS: Balance and gait speed were assessed at baseline and following physical therapy that consisted of exercises to improve specific functional limitations. Outcomes were reassessed 1 month following completion of the physical therapy. RESULTS: Gait and balance outcomes were analyzed using a one-way repeated-measures analysis of variance. Improvement was obtained in balance, which was maintained at 1 month follow-up. Gait speed did not improve to a level of statistical significance. CONCLUSION AND DISCUSSION: After physical therapy, subjects improved in balance and functional performance. An improvement in gait speed may require a longer duration of treatment.

Activities of Daily Living↗
PubMed2001

In vitro and in vivo evaluation of carbamazepine-PEG 6000 solid dispersions.

The present work extended previous physico-chemical investigations on the effects of solid dispersion on the solubility, the dissolution rate and the pharmacokinetic profile of carbamazepine. Solubility studies showed a linear increase in carbamazepine solubility with the increase of PEG 6000 concentration. There is no marked difference between physical mixtures and solid dispersions for the enhancement of carbamazepine solubility by PEG 6000. Less than 60% of pure carbamazepine was dissolved in 90 min. Physical mixtures (carbamazepine phase III) and solid dispersions (carbamazepine phase II) dissolution rates were higher in comparison of the parent drug. The dissolution of carbamazepine phase III was more pronounced than that evoked by the phase II. The dissolution profiles indicated that the percentage of the drug dissolved was dependent on the proportion of PEG 6000. In solid dispersions there was a remarkable enhancement in the dissolution rates of the drug in the vicinity of the eutectic composition as compared with those of corresponding physical mixtures. Hence, the optimum value for the solid dispersion was 80.5+/-1.7% of carbamazepine having dissolved within the first 10 min compared to 40+/-1% for the corresponding physical mixtures of the same composition. Statistical analysis of pharmacokinetic parameters confirmed that the carbamazepine:PEG 6000 binary systems displayed higher bioavailability of the drug than the pure carbamazepine. The area under the curve (AUC) values highlighted the evidence that only slight differences in the bioavailability of the drug occur between physical mixtures and solid dispersions prepared at the 80:20 and 50:50 drug:carrier compositions. However, the mean normalized plasma concentrations showed that standard error deviations are rather wide intervals for pure drug and physical mixtures in comparison to solid dispersions. One additional interesting point to consider is the disappearance of the multiple peaks on the individual kinetic curves of the 50:50 solid dispersion composition. Furthermore, our investigations have highlighted the interest of solid dispersions prepared at < >-eutectic composition as our preliminary data show that the plasma concentration (C(5h)) of the drug for the 15:85 dispersed sample containing 150 mg of carbamazepine is not significantly different from that obtained for the 50:50 dispersed sample containing 300 mg of the drug.

Administration, Oral↗
PubMed2003

Effectiveness of physical therapy for patients with neck pain: an individualized approach using a clinical decision-making algorithm.

OBJECTIVE: The purpose of this study was to determine the effectiveness of an individualized physical therapy intervention in treating neck pain based on a clinical reasoning algorithm. Treatment effectiveness was examined by assessing changes in impairment, physical performance, and disability in response to intervention. DESIGN: One treatment group of 30 patients with neck pain completed physical therapy treatment. The control group of convenience was formed by a cohort group of 27 subjects who also had neck pain but did not receive treatment for various reasons. There were no significant differences between groups in demographic data and the initial test scores of the outcome measures. A quasi-experimental, nonequivalent, pretest-posttest control group design was used. A physical therapist rendered an eclectic intervention to the treatment group based on a clinical decision-making algorithm. Treatment outcome measures included the following five dependent variables: cervical range of motion, numeric pain rating, timed weighted overhead endurance, the supine capital flexion endurance test, and the Patient Specific Functional Scale. Both the treatment and control groups completed the initial and follow-up examinations, with an average duration of 4 wk between tests. RESULTS: Five mixed analyses of variance with follow-up tests showed a significant difference for all outcome measures in the treatment group compared with the control group. After an average 4 wk of physical therapy intervention, patients in the treatment group demonstrated statistically significant increases of cervical range of motion, decrease of pain, increases of physical performance measures, and decreases in the level of disability. The control group showed no differences in all five outcome variables between the initial and follow-up test scores. CONCLUSIONS: This study delineated algorithm-based clinical reasoning strategies for evaluating and treating patients with cervical pain. The algorithm can help clinicians classify patients with cervical pain into clinical patterns and provides pattern-specific guidelines for physical therapy interventions. An organized and specific physical therapy program was effective in improving the status of patients with neck pain.

Adult↗
PubMed1989

Kappa coefficient calculation using multiple ratings per subject: a special communication.

The purpose of this special communication is to describe the application of the Kappa coefficient for the estimation of interobserver agreement. Kappa is a preferred statistic for the estimation of the accuracy of nominal and ordinal data in clinical research by physical therapists. A brief introduction to the properties of the Kappa coefficient is given, and a special case of Kappa for multiple ratings per subject is explained. A FORTRAN program, written specifically for the multiple-ratings situation, is described.

Electronic Data Processing↗
PubMed1996

Leisure time activity and physical fitness in patients with epilepsy.

PURPOSE: To assess social and physical activity by means of a controlled study based on a questionnaire and standardized clinical tests of physical fitness. METHODS: In this controlled study, we assessed several issues of social and physical activity in 136 patients with epilepsy and 145 controls by using a questionnaire. In addition, we investigated physical fitness based on physical parameters such as body mass index and body composition and standardized tests of aerobic and muscle strength endurance and physical flexibility in 35 adult patients and 36 healthy controls. RESULTS: Leisure time habits both at home and outside the home were mainly similar except for visits of friends, which were significantly reduced in patients. Although the general attitude toward sports and physical activity was positive in both groups, and although controls judged sports to be dangerous significantly more often (p = 0.007), controls participated in regular sports significantly more frequently (p = 0.005). The clinical study demonstrated a lack of physical fitness, as suggested by the questionnaire data. Statistical analysis demonstrated significant differences of aerobic endurance (p < 0.001), muscle strength endurance (p < 0.001), and physical flexibility (p < 0.001) in favor of the control subjects. The body mass index was significantly higher in patients (p = 0.03), whereas the body composition revealed a higher body fat ratio only in female patients (p = 0.04). CONCLUSIONS: We conclude that patients with epilepsy suffer from a considerable lack of physical fitness that might have an important impact on their general health and quality of life. In addition to overprotection and reduced mobility, the questionnaire revealed insufficient knowledge among health professionals and sport instructors as a major factor contributing to these results.

Adolescent↗
PubMed2004

[Treatment of patients with neuromuscular disease in a warm climate].

BACKGROUND: Several patient groups request treatment in a warm climate, in spite of the fact that the effects of such treatment are undocumented. MATERIAL AND METHODS: 47 children and 40 adults with neuromuscular diseases were recruited, stratified according to sex, use or non-use of electric wheelchair, primary myopathy or hereditary neuropathy, and randomised into two adult and two children groups. The patients were treated in a rehabilitation centre, either on Lanzarote or in Norway. All patients were monitored with physical tests and questionnaires at the start of the study, at the end of the treatment period, after three months (all groups) and after six months (adults only). RESULTS: No significant differences in effect between the groups were found. In the warm climate, the adult patient group showed a statistically significant improvement regarding pain, quality of life, depression, and results of physical tests at the end of treatment. After three months, the improvement in physical tests was still present. Among adult patients treated in Norway, improvement in physical tests was statistically significant after three months, but not at the end of the treatment period. INTERPRETATION: This study did not show a statistically significant difference between patients with various neuromuscular diseases treated in a warm climate compared to similar patients treated in Norway.

Adult↗
PubMed1992

Effects of physical activity on health status in older adults. II. Intervention studies.

This review has focused on a specific part of the relationship of exercise to health. The overall evidence supporting the health benefits of exercise is substantial and has been critically reviewed recently (18, 94). Thus, the United States Preventive Services Task Force recommends that all adults exercise regularly (94). The conclusions summarized below regarding older adults do not affect this basic recommendation. There is solid evidence that exercise can improve measures of fitness in older adults, particularly strength and aerobic capacity. These exercise effects occur in chronically ill adults, as well as in healthy adults. Because physical fitness is a determinant of functional status, it is logical to ask whether exercise can prevent or improve impairments in functional status in older adults. The evidence that exercise improves functional status is promising, but inconclusive. Problems with existing studies include a lack of randomized controlled trials, a lack of evidence that effects of exercise can be sustained over long periods of time, inadequate statistical power, and failure to target physically unfit individuals. Existing studies suggest that exercise may produce improvements in gait and balance. Arthritis patients may experience long-term functional status benefits from exercise, including improved mobility and decreased pain symptoms. Nonrandomized trials suggest exercise promotes bone mineral density and thereby decreases fracture risk. Recent studies have generally concluded that short-term exercise does not improve cognitive function. Yet the limited statistical power of these studies does not preclude what may be a modest, but functionally meaningful, effect of exercise on cognition. Future research, beyond correcting methodologic deficiencies in existing studies, should systematically study how functional status effects of exercise vary with the type, intensity, and duration of exercise. It should address issues in recruiting functionally impaired older adults into exercise studies, issues in promoting long-term adherence to exercise, and whether the currently low rate of exercise-related injuries in supervised classes can be sustained in more cost-effective interventions that require less supervision.

Activities of Daily Living↗