Magneli phase titanium sub-oxide conductive ceramic Ti_nO_(2n-1) as support for electrocatalyst toward oxygen reduction reaction with high activity and stability

Magneli phase titanium sub-oxide conductive ceramic Tin O2n-1 was used as the support for Pt due to its excellent resistance to electrochemical oxidation, and Pt/Tin O2n-1 composites were prepared by the impregnation-reduction method. The electrochemical stability of Tin O2n-1 was investigated and the results show almost no change in the redox region after oxidation for 20 h at 1.2 V(vs NHE) in 0.5 mol/L H2SO4 aqueous solution. The catalytic activity and stability of the Pt/Tin O2n-1 toward the oxygen reduction reaction(ORR) in 0.5 mol/L H2SO4 solution were investigated through the accelerated aging tests(AAT), and the morphology of the catalysts before and after the AAT was observed by transmission electron microscopy. At the potential of 0.55 V(vs SCE), the specific kinetic current density of the ORR on the Pt/Tin O2n-1 is about 1.5 times that of the Pt/C. The LSV curves for the Pt/C shift negatively obviously with the half-wave potential shifting about 0.02 V after 8000 cycles AAT, while no obvious change takes place for the LSV curves for the Pt/Tin O2n-1. The Pt particles supported on the carbon aggregate obviously, while the morphology of the Pt supported on Tin O2n-1 remains almost unchanged, which contributes to the electrochemical surface area loss of Pt/C being about 2times that of the Pt/Tin O2n-1. The superior catalytic stability of Pt/Tin O2n-1 toward the ORR could be attributed to the excellent stability of the Tin O2n-1 and the electronic interaction between the metals and the support.

THE ASYMMETRIC SYNTHESIS OF AMINO ACIDS UNDER POLYMER-SUPPORTED PHASE TRANSFER CATALYTIC CONDITION

The optical alpha-amino acids were synthesized under room temperature by alkylation of N-(diphenyl methylene) glycine t-butyl ester under polymer-supported phase transfer conditions using polymer-supported cinchonine (or quinine) alkaloids as chiral phase transfer catalysts and dichloromethane as solvent, followed by hydrolysis of the above intermediates introduced to the final products-optical alpha-amino acids. This is a new method for the asymmetric synthesis of alpha-amino acids. The influences of catalyst, temperature, substrates, and organic solvents on the chemical yield and optical purities of products were studied.

The Effect of Luteal-Phase Support with Triptrolin Administration on Implantation and Clinical Pregnancy Rate in Assisted Reproductive Technology

Background: Luteal phase support with GnRH agonist administration has been shown to be effective in improving the outcome of assisted reproductive technology. The goal of this study was to evaluate the effect of single dose Triptrolin (a GnRH agonist) on the probability of the clinical pregnancy rate following embryo transfer (ET) in assisted reproductive techniques (ART). Methods: In this double blinded randomized clinical trial, 340 infertile women who were candidates for intra-cytoplasmic sperm injection (ICSI) were randomly assigned to receive GnRH agonist (Triptrolin) in the luteal phase or placebo. In the intervention group, 0.1 mg Triptrolin was injected subcutaneously, while the control group received normal saline. The clinical pregnancy and implantation rate were compared between the two groups using chi-2 and t-test. P-values less than 0.05 were considered significant. The registration number of this clinical trial is IRCT 2014030916912N1. Results: Administration of 0.1 mg Triptrolin on day 6 after oocyte pick up showed no superiority over placebo in implantation (16.9% - 14%, P = 0.40) and clinical pregnancy rates (32% - 29%, P = 0.66), but the rate of clinical pregnancy was higher in women who were below 27 years of age and those with PCO. Conclusion: Administration of Triptrolin was not superior to placebo for luteal phase support.

Vapor-phase Nitration of Benzene to Nitrobenzene over Supported Sulfuric Acid Catalyst

Vapor-phase nitration of benzene over solid acid catalyst is expected to be a clean process with no sulfuric acid waste. We investigated this process over solid acidic catalysts utilizing diluted nitric acid (60-70%) as nitrating agent, and found that supported sulfuric acid catalyst exhibited a very high catalytic activity. Under the conditions of reaction temperature 160-170℃, space velocity (SV) 1200 h-1, the yield and the space-time yield (STY) of nitrobenzene (NB) based on HNO3 were more than 98% and 0.75 kg穔gcat-1穐-1 over 10% H2SO4/SiO2 (by weight) catalyst respectively.

Traceless solid-phase synthesis of 3-substituted isoxazoles from polystyrene-supported vinyl selenide

A novel facile procedure for traceless solid-phase synthesis of 3-substituted isoxazoles in good yields and with excellent purities using polymer-supported vinyl selenide has been developed.

Oral Dydrogesterone versus Vaginal Micronized Progesterone in Luteal Phase Support after Controlled Ovarian Stimulation Using Long Gonadotropin-Releasing Hormone Agonist in Women Undergoing in Vitro Fertilization/Intracytoplasmic Sperm Injection

Background:?Luteal phase support is indicated after Controlled Ovarian Stimulation (COS) using Long Gonadotropin-Releasing Hormone Agonist (GnRHa) protocol in Women undergoing in Vitro Fertilization (IVF)/Intracytoplasmic Sperm Injection (ICSI). Progesterone is widely used for this indication. Objective: The objective of the current trial is to compare both efficacy and safety of oral dydrogesterone and vaginal micronized progesterone in luteal phase support in women undergoing IVF/ICSI using the long GnRHa protocol. Methods: This open-label randomized controlled study conducted at a private fertility and IVF center in Zagazig, Egypt, during the interval between April 2016 and August 2019. The study included women planned to undergo IVF/ICSI for either male factor infertility, tubal factor infertility, or unexplained infertility. Women with pelvic endometriosis, known reduced ovarian reserve, and women who were known to have poor or high response to ovarian stimulation, as well as women who were stimulated using non-long GnRHa protocol were not included. After embryo transfer, eligible women were randomly allocated into one of the two groups: group I, included women who received oral dydrogesterone 10 mg three times per day;and group II, included women who received vaginal micronized progesterone 400 mg twice per day. The primary outcome was live birth rate. The principal secondary outcome was women satisfaction. Results: Five hundred sixty four women were recruited and randomly allocated into two groups: group I [Oral Dydrogesterone Group] (n = 284), and group II [Vaginal Progesterone Group] (n = 280). Live birth rates [72 (25.4%) vs 69 (24.6%), respectively, RR 1.03, 95% CI (0.77 to 1.37)], ongoing pregnancy rates [79 (27.8%) vs 81 (28.9%), respectively, RR 0.96, 95% CI (0.74 to 1.25)], clinical pregnancy rates [97 (34.2%) vs 95 (33.9%), respectively, RR 1.01, 95% CI (0.80 to 1.27)] and miscarriage rates (per clinical pregnancy) [18 (18.6%) vs 14 (14.7%), respectively, RR 1.26, 95% CI (0.66 to 2.38)] were all comparable in both groups. The rates of vaginal burning [4 (1.4%) vs 32 (11.4%), respectively, RR 0.12, 95% CI (0.04 to 0.34)], vaginal bleeding [9 (3.2%) vs 26 (9.3%), respectively, RR 0.34, 95% CI (0.16 to 0.72)] and overall dissatisfaction [15 (5.3%) vs 68 (24.3%), respectively, RR 0.22, 95% CI (0.13 to 0.37)] were significantly lower among women of group I when compared to women of group II. Conclusion: In conclusion, when compared to vaginal micronized progesterone, oral dydrogesterone seems to be associated with comparable live birth, ongoing pregnancy and clinical pregnancy rates, and significantly lower dissatisfaction and side effects rates, when given as luteal phase support in normal responding women undergoing IVF/ICSI using the long GnRHa protocol.

Solid-phase synthesis of (Z)-allyl iodides from 3-acetoxy-2-methylene-alkanoates with recyclable polymer-supported selenium bromide

Reaction of polystyrene-supported lithium selenide with 3-acetoxy-2-methylene-alkanoates afforded the corresponding allyl selenide resins and subsequent cleavage from the polymer by treating with methyl iodide to furnish （Z）-allyl iodides in good yields and high purities. The polymeric selenium reagent can be regenerated and reused. So it is a environmentally benign reagent.

Solid-phase Synthesis of Vinyl Sulfones Using Polystyrene-supported Selenomethyl Phenyl Sulfone

The solid-phase preparation of vinyl sulfones via a novel polystyrene-supported selenomethyl phenyl sulfone reagent has been reported.

基于Phase^2数值模拟的巷道支护参数优化研究

结合某矿回采巷道地质和技术条件,利用Phase^2数值模拟软件建立了不同锚杆支护参数的模型,通过分析巷道变形及应力分布特征,研究了不同锚杆间距和长度时巷道支护效果。结果表明:Phase^2数值模拟可以为巷道支护参数优化设计提供有效参考,优选支护方案效果良好,有效维护了巷道的稳定性。

Phase2软件在隧洞开挖围岩支护时机中的应用

新奥法支护理论允许围岩变形,"适时"支护,能够保证围岩稳定的前提下,减少支护措施。文章利用phase2软件,引入应力释放法和弹性模量折减法解决"适时"的问题,将新奥法理论应用于德尔西水电站工程引水隧洞支护结构设计中,采用量化、清晰易懂的方式证明了合理地选择支护时机可以优化支护结构、减少工程投资,对隧洞工程支护结构设计具有实际意义。

Palladium nanoclusters immobilized on defective nanodiamond-graphene core-shell supports for semihydrogenation of phenylacetylene

We report a nanocarbon material with nanodiamond(ND) core and graphene shell(ND@G) as a support for Pd nanocatalysts. The designed catalyst performed good selectivity of styrene(85.2%) at full conversion of phenylacetylene and superior stability under mild conditions. Supported Pd catalysts are characterized by means of high resolution transmission electron microscopy(HRTEM), Raman, X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and H2 temperature-programmed reduction(H2-TPR).The results clearly show that formation of the strong metal-support interaction(SMSI) between Pd nanoclusters and the defective graphene shell helpfully modifies the selectivity and stability of the Pd-based catalysts.

Prediction of elevator traffic flow based on SVM and phase space reconstruction

To make elevator group control system better follow the change of elevator traffic flow (ETF) in order to adjust the control strategy,the prediction method of support vector machine (SVM) in combination with phase space reconstruction has been proposed for ETF.Firstly,the phase space reconstruction for elevator traffic flow time series (ETFTS) is processed.Secondly,the small data set method is applied to calculate the largest Lyapunov exponent to judge the chaotic property of ETF.Then prediction model of ETFTS based on SVM is founded.Finally,the method is applied to predict the time series for the incoming and outgoing passenger flow respectively using ETF data collected in some building.Meanwhile,it is compared with RBF neural network model.Simulation results show that the trend of factual traffic flow is better followed by predictive traffic flow.SVM algorithm has much better prediction performance.The fitting and prediction of ETF with better effect are realized.

Study on the Active Phases of Ni-W System Hydrotreating Catalysts

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Pregnancy outcomes following supplementation of single dose GnRH agonist to sustain the luteal phase in antagonist fresh embryo transfer cycles:A multicentric prospective cohort study

Objective:To determine whether a single dose of gonadotropin-releasing hormone(GnRH)agonist administered subcutaneously in addition to the regular progesterone supplementation could provide a better luteal support in antagonist protocol fresh embryo transfer cycles.Methods:This prospective,multicentric,cohort study included total 140 women,70 in each group.Controlled ovarian stimulation was carried out as per fixed GnRH antagonist protocol.The trigger was given with hCG.In vitro fertilization/intracytoplasmic sperm injection(IVF/ICSI)was performed and day-3 embryos were transferred.Patients were divided into groups 1 and 2 based on computer generated randomization sheet.Six days following oocyte retrieval,group 1 received 0.2 mg decapeptyl subcutaneously in addition to regular progesterone support while group 2 received progesterone only.Luteal support was given for 14 days to both groups;if pregnancy was confirmed luteal support was continued till 12 weeks of gestation.The clinical pregnancy rate was the primary outcome.The implantation rate,miscarriage rate,live birth delivery rate,and multiple pregnancy rates were the secondary outcomes.Results:A total of 140 patients were analysed,70 in each group.Clinical pregnancy rates(47.1%vs.35.7%;P=0.17),implantation rates(23.4%vs.18.1%,P=0.24),live birth delivery rates(41.4%vs.27.1%,P=0.08),and multiple pregnancy rates(21.2%vs.16.0%,P=0.74)were higher in group 1 than in group 2.Group 1 had a lower miscarriage rate than group 2(5.7%vs.8.6%;P=0.75).However,these differences were not statistically significant between the two groups.Conclusions:Administration of a single dose of GnRH agonist in addition to regular natural micronized vaginal progesterone as luteal support in GnRH antagonist protocol cycles marginally improves implantation rates,clinical pregnancy rates,and live birth delivery rates.However,more studies with higher sample sizes are needed before any conclusive statements about GnRH agonist as luteal phase support can be made.

Polystyrene-supported Benzyl Selenide: An Efficient Reagent for Highly Stereocontrolled Synthesis of Substituted Olefins

Polystyrene-supported benzyl selenide has been prepared. This novel reagent was treated with LDA to produce a selenium stabilized carbanion, which reacted with alkyl halide, followed by selenoxide syn-elimination, to give substituted olefins stereospecificly.

Polystyrene-supported Selenomethyl-sulfonates: Efficient Reagents for Stereocontrolled Synthesis of Substituted Vinyl Sulfones

Polystyrene-supported selenomethyl-sulfonates have been prepared. These novel reagents were treated with LDA to produce selenium stabilized carbanions, which reacted with alkyl halide and epoxides, followed by selenoxide syn-elimination, to give E-vinyl sulfones and -hydroxy-substituted-E-vinyl sulfones respectively.

黄体酮软胶囊不同给药方案用于激素替代冻融胚胎移植黄体支持的临床结局比较

目的比较黄体酮软胶囊不同给药方案进行激素替代冻融胚胎移植中黄体支持的临床疗效。方法对2019年1月至2021年12月期间在中南大学湘雅医院生殖中心行激素替代冻融胚胎移植的3845例患者临床数据进行回顾性分析,纳入的所有患者黄体支持均采用阴道用黄体酮软胶囊联合口服地屈孕酮治疗,根据阴道用黄体酮软胶囊不同用法将其划分为两组:A组每次使用200 mg,每日3次,共1858个周期;B组每次使用300 mg,每日2次,共1987个周期,评估两组的临床治疗效果。结果两组患者在年龄、不孕年限、体质量指数(BMI)、转化日子宫内膜厚度、转化日雌激素(E_(2))水平、转化日孕激素(P)水平、移植优胚占比等方面比较均无显著差异(P>0.05)。A、B两组患者的活产率分别是34.71%(645/1858)和36.39%(723/1987),而移植囊胚的临床妊娠率分别为52.3%(182/348)和55.37%(397/717),两组间比较均无显著性差异(P>0.05)。人绒毛膜促性腺激素(HCG)阳性率、流产率和异位妊娠率等两组间比较也均无显著性差异(P>0.05)。结论冻融胚胎移植激素替代周期中,采用两种不同剂量不同频次的阴道用黄体酮软胶囊治疗作为黄体支持,能够达到相似的临床疗效。

Separation process study of liquid phase catalytic exchange reaction based on the Pt/C/PTFE catalysts

The liquid phase catalytic exchange(LPCE) reaction is an effective process for heavy water detritiation and production of deuterium-depleted potable water. In the current study, hydrophobic carbon-supported platinum catalysts(Pt/C/PTFE) with high efficiency as reported previously for LPCE were prepared and comprehensive performance evaluation method is applied to evaluate the separation behaviors of LPCE systematically. Experimental results indicate that the optimum reaction temperature of 60–80℃ and the molar feed ratio G/L of 1.5–2.5 would lead to higher separation efficiencies. As to the packing method, a random packing mode with a packing ratio of hydrophobic catalysts 0.25 is recommended. In addition, thermodynamic analysis corresponds well with experimental results under lower temperature and G/L, while the suppression of kinetic factors should not be neglected when T > 80℃ and G/L > 1.5.

相空间重构与改进SMA优化SVR的网络流量预测

为提高网络流量预测精度,提出结合相空间重构与改进黏菌优化支持向量回归的预测模型。为解决黏菌算法收敛慢、易得局部最优的不足,引入3种形态对立学习对种群进行初始化,提高种群多样性;利用非线性反馈因子更新机制,均衡全局搜索与局部开发;设计柯西-高斯混合变异对最优解变异,扩展搜索空间,避免陷入局部最优。利用改进黏菌算法对支持向量回归优化调参,有效解决超参初值敏感缺陷,提高学习精度和收敛速度,以此构建网络流量预测模型。实验结果表明,改进模型预测误差更小,能够实现高精度和实时性预测要求。