Damage and Failure Process of Concrete Structure under Uniaxial Compression Based on Peridynamics Modeling

Peridynamics is a nonlocal formulation of continuum mechanics, which uses integral formulation rather than the spatial partial differential equations. The peridynamic approach avoids using any spatial derivatives, which arise naturally in the classical local theory. It has shown effectiveness and advantage in solving discontinuous problems at both macro- and microscales. In this paper, the peridynamic theory is used to analyze damage and progressive failure of concrete structures. A nonlocal peridynamic model for concrete columns under uniaxial compression is developed. Numerical example illustrates that cracks in a peridynamic body of concrete form spontaneously. The result of the example clarifies the unique advantage of modeling damage accumulation and progressive failure of concrete based on peridynamic theory. This study provides a new promising alternative for analyzing complicated discontinuity problems. Finally, some open problems and future research trends in peridynamics are discussed

Changes in lymphocyte subsets in patients with Guillain-Barré syndrome treated with immunoglobulin

BACKGROUND: Guillain-Barré syndrome (GBS) is an autoimmune condition characterized by peripheral neuropathy. The pathogenesis of GBS is not fully understood, and the mechanism of how intravenous immunoglobulin (IVIG) cures GBS is ambiguous. Herein, we investigated lymphocyte subsets in patients with two major subtypes of GBS (acute inflammatory demyelinating polyneuropathy, AIDP, and acute motor axonal neuropathy, AMAN) before and after treatment with IVIG, and explored the possible mechanism of IVIG action. METHODS: Sixty-four patients with GBS were selected for our study and divided into two groups: AIDP (n = 38) and AMAN (n = 26). Thirty healthy individuals were chosen as the control group. Relative counts of peripheral blood T and B lymphocyte subsets were detected by flow cytometry analysis. RESULTS: In the AIDP group, the percentage of CD4(+)CD45RO(+) T cells was significantly higher, while the percentage of CD4(+)CD45RA(+) T cells was notably lower, than in the control group. After treatment with IVIG, the ratio of CD4(+)/CD8(+) T cells and the percentage of CD4(+)CD45RA(+) T cells increased, while the percentages of CD8(+) T cells and CD4(+)CD45RO(+) T cells decreased significantly, along with the number of CD19(+) B cells. However, there were not such obvious changes in the AMAN group. The Hughes scores were significantly lower in both the AIDP and AMAN groups following treatment with IVIG, but the changes in Hughes scores showed no significant difference between the two groups. CONCLUSIONS: This study suggested that the changes in T and B-lymphocyte subsets, especially in CD4(+)T-lymphocyte subsets, might play an important role in the pathogenesis of AIDP, and in the mechanism of IVIG action against AIDP

Separation and economic recovery of strontium from Nanyishan oil-field water, China

The mass ratio of Ca to Sr is greater than 10 in Nanyishan oil-field water, which causes significant problems during the economic extraction and recovery of selected trace elements in the oil-field water. The oilfield water was isothermally evaporated and various salts such as Li, K, Mg, Ca, Na, Sr, Rb, Cs, Br, and I were obtained from the solution. The Sr content of each phase was determined by ICP-AES, the Sr distribution rule in this process was obtained, and the best separation stage for Sr was identified, to optimize the separation of Sr from Nanyishan oil-field water

Enhancement in Power Conversion Efficiency of GaAs Solar Cells by Utilizing Gold Nanostar Film for Light-Trapping

Light trapping, caused by the introduction of metallic nanoparticles, has been demonstrated to enhance photo-absorption in GaAs solar cells. In this study, we successfully synthesized gold nanostar thin film with hot spots and obtained a notable improvement of power conversion efficiency (PCE) in single-junction and three-junction high-performance GaAs solar cells by incorporating the poly (3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) layer, which enables a much stronger light trapping capability and scattering enhancement than conventional metal nanostructures. Increases of 5.2% and 3.94% in short circuit current density (Isc) were achieved for single-junction cells and three-junction cells while the enhancement in cell PCE was 3.85 and 2.50%, respectively. The relationship between the optical characteristics, the distribution density of the gold NSs and the performance of GaAs solar cells was systemically investigated

A coronary computed tomography angiography study on anatomical characteristics of the diagonal branch of anterior interventricular artery

Background: This study investigated the anatomical characteristics of the ramus intermedius (RI) and its correlation with the proximal diameter of the branch vessels of the left coronary artery (LCA) using coronary computed tomography angiography (CCTA). Materials and methods: We screened patients who underwent CCTA from January to September 2021 and randomly enrolled 267 with RI (RI group) and 134 without RI (control group). We evaluated the anatomical features of RI (distribution, proximal diameter, length). We measured the proximal diameter of the anterior interventricular branch of the left coronary artery (LAD) and the circumflex branch of the left coronary artery (LCX). We compared the differences between groups in the proximal diameter of LAD and LCX and the correlation between gender and each parameter of the left coronary artery (LAD, LCX, RI) within the RI group. In addition, we compared the correlation between the distribution characteristics of RI and the proximal diameter of LAD and LCX within the RI group.  Results: The LAD and LCX proximal diameters in the RI group were significantly smaller than those in the control group (P < 0.05). Comparisons within the RI group showed the following results: The RI distribution, RI diameter and length, and the LCX proximal diameter were not significantly different between male and female patients (P > 0.05), and the LAD proximal diameter was significantly larger in male than in female patients (P < 0.05). There were statistically significant differences in the LAD and LCX proximal diameters between the different RI distribution groups (P < 0.05). Based on the pairwise comparison, there were significant differences in the LAD (LCX) proximal diameter between the RI-beside-the-LAD (LCX) group and the RI-middle group, as well as between the RI-beside-the-LAD (LCX) group and the RI-beside-the-LCX (LAD) group (P < 0.05). Conclusions: A CCTA accurately evaluated the anatomical characteristics of an RI, which has an impact on the proximal diameter of the branch vessels of the left coronary artery (i.e., LAD and LCX), the degree of influence of which is correlated with the RI distribution

Coumarins from the Herb Cnidium monnieri and Chemically Modified Derivatives as Antifoulants against Balanus albicostatus and Bugula neritina Larvae

In the search for new environmental friendly antifouling (AF) agents, four coumarins were isolated from the herbal plant Cnidium monnieri, known as osthole (1), imperatorin (2), isopimpinellin (3) and auraptenol (4). Furthermore, five coumarin derivatives, namely 8-epoxypentylcoumarin (5), meranzin hydrate (6), 2'-deoxymetranzin hydrate (7), 8-methylbutenalcoumarin (8), and micromarin-F (9) were synthesized from osthole. Compounds 1, 2, 4, 7 showed high inhibitory activities against larval settlement of Balanus albicostatus with EC50 values of 4.64, 3.39, 3.38, 4.67 mu g mL(-1). Compound 8 could significantly inhibit larval settlement of Bugula neritina with an EC50 value of 3.87 mu g mL(-1). The impact of functional groups on anti-larval settlement activities suggested that the groups on C-5' and C-2'/C-3' of isoamylene chian could affect the AF activities

Sex Steroids and Osteoarthritis: A Mendelian Randomization Study

ObjectiveSex steroids are thought to contribute to the pathogenesis of osteoarthritis (OA). This study investigated the causal role of sex steroids in site- and sex-specific OA and risk of joint replacement surgery using the Mendelian randomization (MR) method.MethodsInstrumental variables for estradiol, dehydroepiandrosterone sulfate, testosterone (T), and dihydrotestosterone (DHT) were selected. We used the inverse variance weighting (IVW) approach as the main MR method to estimate causal effects based on the summary-level data for OA and joint replacement surgery from genome-wide association studies (GWAS).ResultsA positive causal association was observed between serum T level and risks of hip OA (odds ratio [OR]=1.558, 95% confidence interval [CI]: 1.193–2.034; P=0.001) and hip replacement (OR=1.013, 95% CI: 1.008–1.018; P=2.15×10−8). Serum DHT level was also positively associated with the risk of hip replacement (OR=1.011, 95% CI: 1.006–1.015; P=4.03×10−7) and had potential causality with hip OA (OR=1.398, 95% CI: 1.054–1.855; P=0.020).ConclusionsSerum T and DHT levels may play causal roles in the development of hip OA and contribute to the risk of hip replacement, although the underlying mechanisms require further investigation