Polymyxin B Combined with Minocycline: A Potentially Effective Combination against blaOXA-23-harboring CRAB in In Vitro PK/PD Model

Polymyxin-based combination therapy is commonly used to treat carbapenem-resistant Acinetobacter baumannii (CRAB) infections. In the present study, the bactericidal effect of polymyxin B and minocycline combination was tested in three CRAB strains containing bla_OXA-23 by the checkerboard assay and in vitro dynamic pharmacokinetics/pharmacodynamics (PK/PD) model. The combination showed synergistic or partial synergistic effect (fractional inhibitory concentration index ≤0.56) on the tested strains in checkboard assays. The antibacterial activity was enhanced in the combination group compared with either monotherapy in in vitro PK/PD model. The combination regimen (simultaneous infusion of 0.75 mg/kg polymyxin B and 100 mg minocycline via 2 h infusion) reduced bacterial colony counts by 0.9–3.5 log₁₀ colony forming units per milliliter (CFU/mL) compared with either drug alone at 24 h. In conclusion, 0.75 mg/kg polymyxin B combined with 100 mg minocycline via 2 h infusion could be a promising treatment option for CRAB bloodstream infections.     

Tributylstibine-mediated olefination of carbonyl compounds with bromomalonic ester and with dibromomalonic ester—A possible pathway through a stibonium ylide via halophilic initiation by tertiary stibines

Tributylstibine can mediate the olefination of carbonyl compounds with bromomalonic ester and with dibromomalonic ester. An initial halophilic attack of tributylstibine on the bromine of bromomalonic or dibromomalonic ester forming an ion pair of bromotributylstibonium cation and malonic (A) or bromomalonic ester carbanion (B) , respectively, is proposed. These ion pairs react with carbonyl compounds to achieve subsequent olefination. Alternatively, 2 equiv of A collapse, with elimination of malonic ester, to form stiborane D , and the ion pair B reacts with another equivalent of tributylstibine to form stiborane D. This last undergoes a Wittig-type reaction with carbonyl compound to achieve olefination.     

AQP4 Attenuated TRAF6/NFκB Activation in Acrylamide-Induced Neurotoxicity

Acrylamide (ACR) is present in high-temperature-processed high-carbohydrate foods, cigarette smoke, and industrial pollution. Chronic exposure to ACR may induce neurotoxicity from reactive oxygen species (ROS); however, the mechanisms underlying ACR-induced neurotoxicity remain unclear. We studied 28-day subacute ACR toxicity by repeatedly feeding ACR (0, 15, or 30 mg/kg) to rats. We conducted RNA sequencing and Western blot analyses to identify differences in mRNA expression in the blood and in protein expression in the brain tissues, respectively, of the rats. AQP4 transient transfection was performed to identify potential associations with protein regulation. The rats treated with 30 mg/kg ACR exhibited hind-limb muscle weakness. Matrix metalloproteinase (MMP9) expression was higher in the ACR-treated group than in the control group. ACR induced MMP-9 and AQP4 protein expression in the brain tissues of the rats, which subsequently presented with neurotoxicity. In the in vitro study, Neuro-2a cells were transiently transfected with AQP4, which inhibited MMP-9 and TNF receptor-associated factor 6 (TRAF6) expression, and inhibited ACR induced expression of TRAF6, IκBα, and nuclear factor κB (NFκB). Using a combination of in vivo and in vitro experiments, this study revealed that depressive symptoms associated with ACR-induced neurotoxicity are associated with downregulation of AQP4 and induction of the TRAF6 pathway.     

Effects of MN4-Type Coordination Structure in Metallophthalocyanine for Bio-Inspired Oxidative Desulfurization Performance

Oxidative desulfurization (ODS) is the promising new method for super deep desulfurization of fuel oil. The oxidative desulfurization performance of the metal-N₄-chelates metallophthalocyanines (MPcs) is related to the chemical properties of conjugate structures and the central metal ions. Herein, a biomimetic catalytic system composed of metallophthalocyanines (MPcR₄, M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II); R = -H, -COOH, -NO₂, -NH₂) and molecular O₂ was performed to study the influence of MN₄-type coordination structure in metallophthalocyanines for the degradation of dibenzothiophene (DBT) in model oil containing n-octane. The results reveal that the conjugate structures and the center metal ions of metallophthalocyanines played key roles in oxidative desulfurization performance. The inductive effect of different R substituents strongly affected the electron cloud distribution of the conjugate structures and the catalytic performance. Moreover, the catalytic activity of MPcs, which is related to the d electronic configuration and ligand-field effects, does not sequentially increase with the increase in the d electron number of central metal ions.     

射频等离子制备石墨烯负载Co3O4催化剂及其析氧性能研究

氢能的引入能有效提升配电网的供电可靠性,而电解水制氢是实现低碳转型的关键技术,开发高效的电解水催化剂势在必行。过渡金属氧化物储量大、催化活性高,是具有广阔应用前景的析氧反应催化剂。本文通过射频等离子体处理制备石墨烯上负载Co₃O₄析氧催化剂,XRD、Raman和XPS测试结果显示,二维结构石墨烯的引入加速表面电子迁移,增大了反应面积。等离子体处理促进了纳米粒子在石墨烯上的负载,利用等离子体刻蚀作用在催化剂表面制造出大量碳结构缺陷和氧空位结构,改善了活性位点分布,有效调控Co₃O₄电子结构,提高析氧催化活性。电化学测试表明,本文中合成的Co₃O₄@rGO在电流密度为50 mA·cm^-2时的过电位为410 mV,动力学反应速率较快,表现出优于商业IrO₂的析氧催化活性。     

高质量CdSe单晶生长及其OPO性能研究

本文利用有籽晶的HPVGF法生长了尺寸为φb54 mm× 25 mm的高质量CdSe单晶,晶体为纤锌矿结构,(002)和(110)面的XRD摇摆曲线半高宽分别为54.4"和45.6".使用红外显微镜和扫描电镜-能谱分析仪对晶体内部的夹杂相进行测试,表明晶体内部存在小尺寸富Se夹杂相.CdSe晶片在2.5～20 μm范围内的透过率高于68;,平均吸收系数为0.037 cm-1.制备出尺寸为10mm×12 mm×50mm且满足第Ⅱ类相位匹配条件的CdSe晶柱,在重频1 kHz,波长2.09 μm的Ho∶ YAG调Q泵浦源激励下,实现了中心波长为11.47 μm,线宽为33.2 nm的激光输出,最大输出功率为389 mW.     

Recursive second-order Volterra filter based on Dawson function for chaotic memristor system identification

Nonlinear Dynamics - In this paper, we propose a modified version of exponential cost function to improve the stability of adaptive algorithm, where the recursive algorithm is based on the Dawson...     

Reduction in the $$\mathbf {(4+1)}$$(4+1)-dimensional Fokas equation and their solutions

Nonlinear Dynamics - An integrable extension of the Kadomtsev–Petviashvili (KP) and Davey–Stewartson (DS) equations is investigated in this paper. We will refer to this integrable...     

输电铁塔四地脚螺栓塔脚板抗拉承载力试验与计算方法研究

针对架空输电线路铁塔中常用的四地脚螺栓塔脚板进行了抗拉承载力试验和理论计算方法研究。首先,选取8个试件进行塔脚板抗拉承载力试验研究,分析塔脚底板板厚及有无加劲板对塔脚板抗拉承载力的影响;其次,通过有限元模拟塔脚板的应力分布情况,并结合“塑性分析,弹性设计”的思想,提出了一种基于屈服线理论的四地脚螺栓塔脚板抗拉承载力计算公式;最后,与试验结果、有限元仿真结果、已有技术规定中的计算结果进行了对比。结果表明:建议公式与试验结果和仿真结果较为吻合,相关技术规定中的计算结果偏于保守,验证了本文建议公式的精确性;底板厚度和加劲板的作用对塔脚板承载力影响较大。研究结果可为输电铁塔四地脚螺栓塔脚板结构设计提供参考。     

BC/CoNi2S4@PPy柔性复合电极材料的制备及电化学性能

本文采用溶剂热、原位聚合和真空抽滤相结合的方法制备了用于超级电容器的细菌纤维素/镍钴硫化物/聚吡咯(BC/CoNi2S4@PPy)柔性电极材料,通过X 射线衍射、场发射扫描电镜、红外光谱、氮气吸脱附、拉伸强度和接触角表征了材料的形貌结构、组成、机械性能和亲水性,并采用循环伏安法和恒电流充放电测试了复合材料的电化学性能....