Cost-effective promoter-doped Cu-based bimetallic catalysts for the selective hydrogenation of C2H2 to C2H4: the effect of the promoter on selectivity and activity.

In order to probe into the effect of the promoter on the selectivity and activity towards C2H4 formation in the selective hydrogenation of C2H2 over cost-effective Cu-based bimetallic catalysts, different metal promoter M-modified Cu catalysts including Ni, Ag, Au, Pt, Pd and Rh have been employed to fully investigate the selective hydrogenation of C2H2 using density functional theory calculations together with microkinetic modeling. The results show that the adsorption ability of C2H2 is far stronger than that of C2H4 on different Cu-based catalysts, which favors the activation and hydrogenation of C2H2. The type of promoter obviously affects the preferable pathway of C2H2 selective hydrogenation, and ultimately alters the selectivity of the products; only on PdCu(211) and AgCu(211) surfaces, the C2H4 desorption pathway is the most favorable for gaseous C2H4 formation, suggesting that the promoter Pd or Ag has good selectivity towards C2H4 formation. The catalytic activity towards C2H4 formation follows the order PdCu(211) > PtCu(211) > NiCu(211) > RhCu(211) > AgCu(211) > AuCu(211) > Cu(211), indicating that the promoter can obviously increase the catalytic activity towards C2H4 formation compared to the Cu catalyst alone. Thus, the promoter Pd-modified Cu catalysts exhibit the highest catalytic activity and selectivity for C2H2 hydrogenation to C2H4. This work provides a method to evaluate and obtain the type of promoter with the best activity and selectivity in the selective hydrogenation of C2H2.

Evaluation of Singh Index and Osteoporosis Self-Assessment Tool for Asians as risk assessment tools of hip fracture in patients with type 2 diabetes mellitus.

BACKGROUND: Type 2 diabetes mellitus (T2DM), an epidemic disease around world, has recently been identified as a risk factor for osteoporosis-associated fracture. However, there is no consensus on the best method of assessing fracture risk in patients with T2DM. The aim of this study was to evaluate the usefulness of the Osteoporosis Self-Assessment Tool for Asians (OSTA) and the Singh Index (SI) in hip fracture risk assessment in patients with T2DM. METHODS: We enrolled 261 postmenopausal women with T2DM: 87 had hip fracture resulting from low-energy trauma and 174 age-matched controls had no fracture (two controls per fracture case). Bone mineral density (BMD) was measured with dual-energy X-ray absorptiometry in the lumbar spine and hip region. The SI was obtained from standard antero-posterior radiographs of the pelvis. The OSTA was calculated with a formula based on weight and age. Data were analyzed with descriptive statistics and tests of difference. Receiver operating characteristic analysis was used to determine optimum cutoff values, sensitivity, and specificity of screening methods. Discriminative abilities of different screening tools were compared with the area under the curve (AUC). RESULTS: There were significant differences in BMD at all sites (lumbar spine, femoral neck, trochanter, and total hip) and in SI between the fracture and non-fracture groups (P < 0.05). There was no significant difference in OSTA between the groups (P > 0.05). The area under the curve was 0.747 (95% CI: 0.680-0.813) for lumbar spine BMD, 0.699 (95% CI: 0.633-0.764) for total hip BMD, 0.659 (95% CI: 0.589-0.729) for femoral neck BMD, 0.631 (95% CI: 0.557-0.704) for trochanter BMD, 0.534 (95% CI: 0.459-0.610) for OSTA, 0.636 (95% CI: 0.564-0.709) for SI, and 0.795 (95% CI: 0.734-0.857) for OSTA plus SI. The AUC for combined OSTA plus SI was significantly superior to other parameters besides BMD of the lumbar spine. CONCLUSIONS: The combination of OSTA plus SI could be a clinical alternative tool for screening of hip fracture risk in large diabetic populations. These tests are inexpensive and simple to perform and could be especially useful in areas where BMD measurement is not accessible.

[Development and assessment of a chemiluminescence assay kit for detecting anti-HEV IgG].

OBJECTIVE: To develop an anti-hepatitis E virus (anti-HEV) IgG chemiluminescence assay kit and assess its clinical application. METHODS: The HEV recombinant antigen was used as coating antigen, horseradish peroxidase (HRP)-conjugated monoclonal anti-human IgG as the secondary antibody, and the luminol chemiluminescent reaction system as a substrate. The sensitivity, specificity, precision and other technical indicators of the kit were evaluated using the HEV national reference product, and a contrast experiment was conducted on 1012 serum samples by the kit developed in this research and a commercialized anti-HEV IgG chemiluminescence assay kit. RESULTS: The sensitivity, specificity, precision and stability of all the three batches of kit reached national standard. In the detection of 1012 clinical serum samples, the positive coincidence rate of both kits was 97.4%, the negative coincidence rate was 99.4%, and the total coincidence rate reached 98.4%. CONCLUSION: An anti-HEV IgG chemiluminescence assay kit has been successfully developed. The kit is of high sensitivity and specificity, easy to operate. It is applicable to the clinical diagnosis and epidemiological survey of HEV infection.

Laparoendoscopic single-site urethrovesical anastomosis training in an economical porcine model.

PURPOSE: To develop an economical animal model for laparoendoscopic single-site surgery (LESS) urethrovesical anastomosis (UVA) training. MATERIALS AND METHODS: A homemade single-port device was used and the uterus cervix and the ileum were chosen to simulate UVA to reduce costs. Ten trainees were randomly divided into two groups: the conventional LESS UVA (CLUVA) group and the transurethral assistant LESS UVA (TALUVA) group. In TALUVA, a laparoscopic forceps was inserted through the urethra to assist operation after the bladder neck was disconnected, whereas CLUVA followed the conventional steps. Anastomosis time and knotting time were recorded, and the learning curves of both groups were analyzed. After training, questionnaires were given to the trainees to assess the difficulties and the satisfaction of the training. RESULTS: The final mean operating time significantly declined in both groups. Except for the first lesson, the trainees in the TALUVA group operated faster than those in the other group. The results from the questionnaires show that all trainees were satisfied with the training, and LESS UVA was considered more difficult in the CLUVA group than in the TALUVA group. CONCLUSIONS: The female porcine model for LESS UVA was feasible and cost-effective. TALVUA could effectively reduce the difficulties involved in LESS UVA.

Squeeze-and-breathe evolutionary Monte Carlo optimization with local search acceleration and its application to parameter fitting.

Estimating parameters from data is a key stage of the modelling process, particularly in biological systems where many parameters need to be estimated from sparse and noisy datasets. Over the years, a variety of heuristics have been proposed to solve this complex optimization problem, with good results in some cases yet with limitations in the biological setting. In this work, we develop an algorithm for model parameter fitting that combines ideas from evolutionary algorithms, sequential Monte Carlo and direct search optimization. Our method performs well even when the order of magnitude and/or the range of the parameters is unknown. The method refines iteratively a sequence of parameter distributions through local optimization combined with partial resampling from a historical prior defined over the support of all previous iterations. We exemplify our method with biological models using both simulated and real experimental data and estimate the parameters efficiently even in the absence of a priori knowledge about the parameters.