Search

Background: Atrial fibrillation (AF) can lead to a decline in left atrial appendage (LAA) function, potentially increasing the likelihood of LAA thrombus (LAAT) and spontaneous echo contrast (SEC). Measuring LAA flow velocity through transesophageal echocardiography (TEE) is currently the primary method for evaluating LAA function. This study aims to explore the potential correlation between anterior mitral annular plane systolic excursion (aMAPSE) and LAA stasis in patients with non-valvular atrial fibrillation (NVAF). Methods: A total of 465 patients with NVAF were enrolled between October 2018 and November 2021. Transthoracic echocardiography (TTE) and TEE were performed before scheduled electrical cardioversion. Propensity score matching (PSM) was used to balance confounders between the groups with and without LAAT/dense SEC. Results: Patients in the LAAT/dense SEC group showed increased left atrial (LA) diameter, LAA area, alongside reduced left ventricular ejection fraction (LVEF), LAA velocity, conjunction thickening ratio, aMAPSE, and LAA fraction area change (FAC) compared to those in the non-LAAT/dense SEC group. Multivariate logistic regression analysis identified aMAPSE and LAA FAC as independent predictors for LAAT/dense SEC. Specifically, an aMAPSE of <6.76 mm and an LAA FAC of <29.65% predicted LAAT/dense SEC with high diagnostic accuracy, demonstrated by an area under the curve (AUC) of 0.81 (sensitivity 0.81, specificity 0.80) for aMAPSE, and an AUC of 0.80 (sensitivity 0.70, specificity 0.84) for LAA FAC. Conclusions: Both aMAPSE and LAA FAC independently correlated with and accurately predict LAAT/dense SEC. Incorporating aMAPSE into routine TEE evaluations for LAA function alongside LAA flow velocity is recommended. [ABSTRACT FROM AUTHOR]

Background: Numerous studies on animals evidenced that conjugated linoleic acid (CLA) could decrease blood pressure (BP) in several rat models. However, such beneficial effect is not completely supported by studies on humans. Methods: We searched the Pubmed, Cochrane Library, and the ClinicalTrials.gov databases for relevant randomized, double-blind placebo-controlled trials up to August 2014 to perform a meta-analysis. A random-effects model was used to calculate the combined treatment effects. Results: Eight studies with nine trials, which involved 638 participants with CLA supplementation ranging from 2.0 g/day to 6.8 g/day, were included in this meta-analysis. Compared with placebo, the pooled estimate of change was -0.03 mm Hg (95% CI: -2.29, 2.24, P = 0.98) and 0.69 mm Hg (95% CI: -1.41, 2.80, P = 0.52) in systolic and diastolic BPs, respectively. No significant heterogeneity across studies for systolic BP; however, substantial heterogeneity for diastolic BP was identified. Publication bias was not found for both systolic and diastolic BPs. Conclusion: The findings of this meta-analysis did not support the overall favorable effect of CLA supplementation on BP regulation. [ABSTRACT FROM AUTHOR]

Quantifying three-dimensional spatial distributions of pores and material compositions in samples is a key materials characterization challenge, particularly in samples where compositions are distributed across a range of length scales, and where such compositions have similar X-ray absorption properties, such as in coal. Consequently, obtaining detailed information within sub-regions of a multi-length-scale sample by conventional approaches may not provide the resolution and level of detail one might desire. Herein, an approach for quantitative high-definition determination of material compositions from X-ray local computed tomography combined with a data-constrained modelling method is proposed. The approach is capable of dramatically improving the spatial resolution and enabling finer details within a region of interest of a sample larger than the field of view to be revealed than by using conventional techniques. A coal sample containing distributions of porosity and several mineral compositions is employed to demonstrate the approach. The optimal experimental parameters are pre-analyzed. The quantitative results demonstrated that the approach can reveal significantly finer details of compositional distributions in the sample region of interest. The elevated spatial resolution is crucial for coal-bed methane reservoir evaluation and understanding the transformation of the minerals during coal processing. The method is generic and can be applied for three-dimensional compositional characterization of other materials. [ABSTRACT FROM AUTHOR]

Calorimetric measurements are performed to determine the specific heat of Si-x at.% Ge (where x = 0, 10, 30, 50, 70, 90 and 100) alloys within a broad temperature range from 123 to 823 K. The measured specific heat increases dramatically at low temperatures, and the composition dependence of specific heat is evaluated from the experimental results. Meanwhile, the specific heat at constant volume, the thermal expansion, and the bulk modulus of Si and Ge are investigated by the first principle calculations combined with the quasiharmonic approximation. The negative thermal expansion is observed for both Si and Ge. Furthermore, the isobaric specific heat of Si and Ge is calculated correspondingly from 0 K to their melting points, which is verified by the measured results and accounts for the temperature dependence in a still boarder range. [ABSTRACT FROM AUTHOR]

The thermal expansion of Ni3Al intermetallic compound is determined by a thermal dilatometer and simulated by the molecular dynamics method. The results of the linear thermal expansion coefficients are presented from 200 K up to the maximum temperature of 1600 K. The single phase of Ni3Al intermetallic compound is confirmed by x-ray diffraction together with DSC melting and solidification peaks, from which the solidus and the liquidus temperatures are obtained to be 1660 and 1695 K, respectively. The measured linear thermal expansion coefficient increases from 1.5 × 10−5 to 2.7 × 10−5 K−1 in the experimental temperature range, in good agreement with the data obtained by the molecular dynamics simulation, just a slight difference from the temperature dependence coefficient. Furthermore, the atomic structure and position are presented to reveal the atom distribution change during thermal expansion of Ni3Al compound. [ABSTRACT FROM AUTHOR]

Motivation: Identification of post-translationally modified proteins has become one of the central issues of current proteomics. Spectral library search is a new and promising computational approach to mass spectrometry-based protein identification. However, its potential in identification of unanticipated post-translational modifications has rarely been explored. The existing spectral library search tools are designed to match the query spectrum to the reference library spectra with the same peptide mass. Thus, spectra of peptides with unanticipated modifications cannot be identified. [ABSTRACT FROM PUBLISHER]