123 research outputs found
Microstructural and molecular level characterisation of plastic crystal phases of pyrrolidinium trifluoromethanesulfonyl salts
Ambient temperature conductive plastic crystal phases of alkylmethylpyrrolidinium trifluoromethanesulfonyl amide (TFSA) salts are studied using positron annihilation lifetime spectroscopy (PALS) to examine the role of vacancy size and concentration in conductivity. The ethyl methylpyrrolidinium TFSA salt (P12 TFSA) has larger vacancies and a greater concentration of vacancies than the dimethylpyrrolidinium TFSA salt (P11 TFSA) over the temperature range investigated. The relative vacancy size and concentration vary with temperature and reflect the solid–solid transitions as measured by differential scanning calorimetry (DSC). P12 TFSA has greater conductivity than P11 TFSA and has furthermore been observed to exhibit slip planes at room temperature. P12 TFSA has greater entropy changes associated with solid–solid phase transitions below the melting point than P11 TFSA possibly indicating greater rotational freedom in P12 TFSA. These results support the notion that the diffusion, conduction, and plastic flow properties of the pyrrolidinium TFSA salts are derived from the lattice vacancies.<br /
Changes in sputum composition during 15min of sputum induction in healthy subjects and patients with asthma and chronic obstructive pulmonary disease
SummaryIntroductionThe use of sputum induction by inhalation of hypertonic saline to study the cellular and biochemical composition of the airways allows noninvasive sampling of the airways content and identification of markers of airways inflammation.ObjectiveThe present study aimed to identify possible changes in the cellular composition of induced sputum between samples obtained sequentially (three periods of 5min each) during one sputum induction. Moreover, difference between these samples and the mixed one (mixture of samples obtained after 5, 10 and 15min of induction) was investigated.MethodsForty-six subjects (10 healthy volunteers, 12 patients with chronic obstructive pulmonary disease (COPD) and 24 patients with asthma) (mean age 53.0±14.0yr, forced expiratory volume in one second (FEV1) 71.8±19.0% pred) produced sputum after three consecutive 5min periods of hypertonic (4.5%) saline inhalation. Stained cytospins from the three periods separately and from the mixed sample were produced and analyzed.ResultsThe mean percentage of neutrophils, eosinophils, lymphocytes and epithelial cells did not change significantly in samples obtained consecutively after 5, 10 and 15min of the induction procedure. There was no significant difference in the cellular composition of samples obtained after 5, 10 and 15min of induction and the cellular composition of the mixed sample (P=0.06).ConclusionThe separate analysis of induced sputum from three consecutive sampling and the mixed sample did not demonstrate significant changes in their cellular composition. Fifteen minutes induction procedure with the fixed concentration of hypertonic saline and processing of the mixed sample can be recommended for clinical settings and clinical trials
Left atrial volume predicts adverse cardiac and cerebrovascular events in patients with hypertrophic cardiomyopathy
<p>Abstract</p> <p>Aims</p> <p>To prospectively evaluate the relationship between left atrial volume (LAV) and the risk of clinical events in patients with hypertrophic cardiomyopathy (HCM).</p> <p>Methods</p> <p>We enrolled a total of 141 HCM patients with sinus rhythm and normal pump function, and 102 patients (73 men; mean age, 61 ± 13 years) who met inclusion criteria were followed for 30.8 ± 10.0 months. The patients were divided into two groups with or without major adverse cardiac and cerebrovascular events (MACCE), a composite of stroke, sudden death, and congestive heart failure. Detailed clinical and echocardiographic data were obtained.</p> <p>Results</p> <p>MACCE occurred in 24 patients (18 strokes, 4 congestive heart failure and 2 sudden deaths). Maximum LAV, minimum LAV, and LAV index (LAVI) corrected for body surface area (BSA) were significantly greater in patients with MACCE than those without MACCE (maximum LAV: 64.3 ± 25.0 vs. 51.9 ± 16.0 ml, p = 0.005; minimum LAV: 33.9 ± 15.1 vs. 26.2 ± 10.9 ml, p = 0.008; LAVI: 40.1 ± 15.4 vs. 31.5 ± 8.7 ml/mm<sup>2</sup>, p = 0.0009), while there were no differences in the other echocardiographic parameters.</p> <p>LAV/BSA of ≥ 40.4 ml/m<sup>2 </sup>to identify patients with cardiovascular complications with a sensitivity of 73% and a specificity of 88%.</p> <p>Conclusion</p> <p>LAVI may be an effective marker for detecting the risk of MACCE in patients with HCM and normal pump function.</p
Совершенствование технологии сооружения подводных переходов трубопроводов проложенных методом горизонтально-направленного бурения
Цель работы – разработка рекомендаций по применению технологии прокладки трубопроводов методом горизонтально-направленного бурения с применением защитного устройства.
В процессе исследования проводились сравнительная характеристика существующих методов бестраншейной прокладки трубопроводов, расчет основных характеристик подводного перехода, подбор защитного устройства, исследование напряженно-деформированного состояния трубопровода с помощью конечно-элементного моделирования в программном комплексе Ansys.
В результате исследования подобраны оптимальные параметры подводного перехода, методом конечно-элементного моделирования в программном комплексе Ansys определено напряженно-деформированнон состояние трубопровода с защитным устройством и без него.The purpose of the work is to develop recommendations for the application of pipeline laying technology by the method of horizontal directional drilling using a protective device.
In the process of the research, the existing methods of trenchless pipeline laying, the calculation of the main characteristics of the underwater crossing, the selection of the protective device, the study of the stress-strain state of the pipeline using finite element modeling in the software complex Ansys were compared. As a result of the research, optimal parameters of the underwater transition were selected, the finite element method in the software complex Ansys determined the stress-strain state of the pipeline with the protective device and without it
Relationship between the anti-inflammatory properties of salmeterol/fluticasone and the expression of CD4+CD25+Foxp3+ regulatory T cells in COPD
<p>Abstract</p> <p>Background</p> <p>Salmeterol and fluticasone combination (SFC) has anti-inflammatory effects and improves clinical symptoms in patients with chronic obstructive pulmonary disease (COPD). However, the anti-inflammatory mechanism of SFC remains unclear. In this study, we investigated the inflammatory responses of COPD, as well as the relationship of the inflammatory factors with the levels of CD4<sup>+</sup>CD25<sup>+</sup>Foxp3<sup>+ </sup>regulatory T cells (Foxp3<sup>+</sup>Tregs) after SFC therapy.</p> <p>Methods</p> <p>Twenty-one patients with moderate or severe COPD received treatment with 50/500 μg of SFC twice a day for 12 weeks. Before and after treatment, the patients were evaluated using the Modified Medical Research Council (MMRC) dyspnea scale and by conducting a 6-min walk test. The number of neutrophils, monocytes and lymphocytes in induced sputum were counted. Levels of cytokines, including pre-inflammatory IL-8, TNF-α, IL-17A and cytokine IL-10, in the sputum supernatant and peripheral blood were measured by ELISA. The proportion of Foxp3<sup>+</sup>Tregs in the total CD4<sup>+ </sup>T cell of the peripheral blood was determined by flow cytometry. The relationship between IL-17A levels and the percentage of Foxp3<sup>+</sup>Tregs was analyzed by statistical analysis.</p> <p>Results</p> <p>After treatment with SFC, the forced expiratory volume in 1 s as a percentage of predicted values (FEV1%) and the 6-min walk distance in the COPD patients significantly increased, while dyspnea scores decreased. The total number of cells, neutrophils, and the percentage of neutrophils in induced sputum reduced notably, while the proportion of monocytes was significantly increased. Levels of the inflammatory cytokines IL-8, TNF-α, and IL-17A in the sputum supernatant and in the blood were markedly lowered, while IL-10 levels were unchanged. The proportion of Foxp3<sup>+</sup>Tregs in the total CD4<sup>+</sup>T cell population in the peripheral blood was drastically higher than that before treatment. The level of IL-17A was negatively correlated with the proportion of Foxp3<sup>+</sup>Tregs in CD4<sup>+</sup>T cells.</p> <p>Conclusion</p> <p>SFC can reduce the levels of inflammatory factors and improve symptoms of COPD. The levels of inflammatory factors are associated with the variation of Foxp3<sup>+</sup>Tregs in COPD.</p> <p>Trial registration</p> <p>This study was registered with <url>http://www.chictr.org</url> (Chinese Clinical Trial Register) as follows: ChiCTR-TNC-10001270</p
Searching biomedical databases on complementary medicine: the use of controlled vocabulary among authors, indexers and investigators
BACKGROUND: The optimal retrieval of a literature search in biomedicine depends on the appropriate use of Medical Subject Headings (MeSH), descriptors and keywords among authors and indexers. We hypothesized that authors, investigators and indexers in four biomedical databases are not consistent in their use of terminology in Complementary and Alternative Medicine (CAM). METHODS: Based on a research question addressing the validity of spinal palpation for the diagnosis of neuromuscular dysfunction, we developed four search concepts with their respective controlled vocabulary and key terms. We calculated the frequency of MeSH, descriptors, and keywords used by authors in titles and abstracts in comparison to standard practices in semantic and analytic indexing in MEDLINE, MANTIS, CINAHL, and Web of Science. RESULTS: Multiple searches resulted in the final selection of 38 relevant studies that were indexed at least in one of the four selected databases. Of the four search concepts, validity showed the greatest inconsistency in terminology among authors, indexers and investigators. The use of spinal terms showed the greatest consistency. Of the 22 neuromuscular dysfunction terms provided by the investigators, 11 were not contained in the controlled vocabulary and six were never used by authors or indexers. Most authors did not seem familiar with the controlled vocabulary for validity in the area of neuromuscular dysfunction. Recently, standard glossaries have been developed to assist in the research development of manual medicine. CONCLUSIONS: Searching biomedical databases for CAM is challenging due to inconsistent use of controlled vocabulary and indexing procedures in different databases. A standard terminology should be used by investigators in conducting their search strategies and authors when writing titles, abstracts and submitting keywords for publications
Imitators of exercise-induced bronchoconstriction
Exercise-induced bronchoconstriction (EIB) is described by transient narrowing of the airways after exercise. It occurs in approximately 10% of the general population, while athletes may show a higher prevalence, especially in cold weather and ice rink athletes. Diagnosis of EIB is often made on the basis of self-reported symptoms without objective lung function tests, however, the presence of EIB can not be accurately determined on the basis of symptoms and may be under-, over-, or misdiagnosed. The goal of this review is to describe other clinical entities that mimic asthma or EIB symptoms and can be confused with EIB
The genetic basis of hypertrophic cardiomyopathy in cats and humans
Mutations in genes that encode for muscle sarcomeric proteins have been identified in humans and two breeds of domestic cats with hypertrophic cardiomyopathy (HCM). This article reviews the history, genetics, and pathogenesis of HCM in the two species in order to give veterinarians a perspective on the genetics of HCM. Hypertrophic cardiomyopathy in people is a genetic disease that has been called a disease of the sarcomere because the preponderance of mutations identified that cause HCM are in genes that encode for sarcomeric proteins (Maron and Maron, 2013). Sarcomeres are the basic contractile units of muscle and thus sarcomeric proteins are responsible for the strength, speed, and extent of muscle contraction. In people with HCM, the two most common genes affected by HCM mutations are the myosin heavy chain gene (MYH7), the gene that encodes for the motor protein β-myosin heavy chain (the sarcomeric protein that splits ATP to generate force), and the cardiac myosin binding protein-C gene (MYBPC3), a gene that encodes for the closely related structural and regulatory protein, cardiac myosin binding protein-C (cMyBP-C). To date, the two mutations linked to HCM in domestic cats (one each in Maine Coon and Ragdoll breeds) also occur in MYBPC3 (Meurs et al., 2005, 2007). This is a review of the genetics of HCM in both humans and domestic cats that focuses on the aspects of human genetics that are germane to veterinarians and on all aspects of feline HCM genetics
Update on hypertrophic cardiomyopathy and a guide to the guidelines
Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiovascular disorder, affecting 1 in 500 individuals worldwide. Existing epidemiological studies might have underestimated the prevalence of HCM, however, owing to limited inclusion of individuals with early, incomplete phenotypic expression. Clinical manifestations of HCM include diastolic dysfunction, left ventricular outflow tract obstruction, ischaemia, atrial fibrillation, abnormal vascular responses and, in 5% of patients, progression to a 'burnt-out' phase characterized by systolic impairment. Disease-related mortality is most often attributable to sudden cardiac death, heart failure, and embolic stroke. The majority of individuals with HCM, however, have normal or near-normal life expectancy, owing in part to contemporary management strategies including family screening, risk stratification, thromboembolic prophylaxis, and implantation of cardioverter-defibrillators. The clinical guidelines for HCM issued by the ACC Foundation/AHA and the ESC facilitate evaluation and management of the disease. In this Review, we aim to assist clinicians in navigating the guidelines by highlighting important updates, current gaps in knowledge, differences in the recommendations, and challenges in implementing them, including aids and pitfalls in clinical and pathological evaluation. We also discuss the advances in genetics, imaging, and molecular research that will underpin future developments in diagnosis and therapy for HCM
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