Investigation of Bimetallic Nickel Catalysts in Catalyst‐Transfer Polymerization of π‐Conjugated Polymers

A comparative study involving bimetallic nickel catalysts designed from disubstituted N,N,N′,N′‐tetra(diphenylphosphanylmethyl)benzene diamine bridging ligands is reported. Catalyst behavior is explored in the Kumada catalyst‐transfer polymerization (KCTP) using poly(3‐hexylthiophene) (P3HT) as the model system. The success of a controlled polymerization is monitored by analyzing monomer conversion, degree of polymerization, end‐group identity, and molecular weight distribution. The characterization of P3HT obtained from KCTP initiated with the bimetallic catalysts shows chain‐growth behavior; however, the presence of Br/Br end‐groups and broader molecular weight distribution reveals a reduced controlled polymerization compared to the commonly employed Ni(dppp)Cl₂. The observed increase in intermolecular chain transfer and termination processes in KCTP initiation with the bimetallic catalysts can be attributed to a weaker Ni(0)‐π‐aryl complex interaction, which is caused by increased steric crowding of the coordination sphere.     

铸造支架联合NITI悬臂梁矫正舌倾下颌磨牙的临床效果评价

目的 评价NITI悬臂梁在矫正舌倾下颌磨牙中的临床效果。方法 选择16例单侧下颌第二磨牙舌倾的病例为研究对象,带垫铸造支架连接双侧下颌后牙,提供颌内支抗、解除咬合锁结,0.018英寸×0.025英寸或0.019英寸×0.025英寸NITI悬臂梁提供颊向旋转力矩和压低力。采用Graphpad Prism 6.0 软件对治疗前、后所测数据进行配对 t 检验。结果 所有患牙均获得直立,牙轴变化24°±1.2°（P<0.01）,近中舌尖到正中矢状面垂直距离变化（3±0.8） mm（P<0.05）,牙周状况良好,咬合关系稳定。结论 铸造支架联合NITI 悬臂梁可提供有效力学机制,矫正舌倾下颌磨牙。     

Prediction of steady state bioequivalence relationships using single dose data II-nonlinear kinetics

Two nonlinear pharmacokinetic models were simulated to investigate the relationship between single and multiple dose bioequivalency parameters for drugs such as phenytoin and propranolol which exhibit either saturable elimination kinetics or a capacity limited first pass effect. Mean Tmax, Cmax and area under the plasma-concentration time curve values from 0 to infinity (AUC 0-infinity) were compared after a single and multiple dose(s) of a test or reference drug. The aim was to determine if there were systematic changes in the limits of the single dose confidence interval at steady state that would limit the usefulness of confidence intervals following a single dose in accurately predicting bioavailability following multiple dosing. The 90 per cent confidence interval expressed as a percentage of the reference mean for Tmax, Cmax, and AUC 0-infinity showed model dependent changes from single to multiple dosing in response to the level of data error and changes in absorption. Changes in clearance also seemed to have a marked effect on the observed limits of the single and multiple dose confidence intervals especially for Cmax which showed a characteristic change in the intervals as a function of the clearance ratio. The model used to describe phenytoin had confidence intervals for Cmax and AUC 0-infinity from single to multiple dosing that were similar to that seen for the experimental data. However, the model predictions for Tmax confidence intervals following single and multiple dosing was at variance with the experimental data for formulations A and B.     

鼠李糖脂分批式发酵动力学模型

根据3.7 L瑞士Bioengineer KLF2000型发酵罐分批发酵的实验数据,利用GraphPad Prism软件对假单胞菌BS-03产鼠李糖脂生物表面活性剂的发酵动力学模型进行非线性拟合,说明Logistic模型和L-P模型能较好的描述假单胞菌BS-03发酵过程中的菌体生长、鼠李糖脂合成和限制性基质的消耗动力学。     

Sonographic evaluation of gallbladder kinetics: in vitro and in vivo comparison of different methods to assess gallbladder emptying.

In an in vitro study, 10 gallbladders of adult pigs and 6 gallbladders of lambs, all removed immediately after slaughtering, were stimulated in a water bath by electric means to induce active contraction. Gallbladder emptying was followed by ultrasonography employing five measurement procedures: (1) gallbladder width, (2) longitudinal planimetry, (3) transverse planimetry, (4) ellipsoid method, and (5) sum of cylinders method. In an in vivo investigation, gallbladder emptying of 30 volunteers (12 healthy subjects, 18 diabetics) was evaluated in the same way after ingestion of a fatty meal. Gallbladder width was found to be unsuitable to estimate the decrease in gallbladder volume due to a nonlinear relation of the parameters. Longitudinal planimetry tended to be less valid than transverse planimetry in assessing gallbladder volume reduction. The most valid estimation of gallbladder volume decreases was obtained by the two three-dimensional procedures. However, in neither in vitro nor in vivo could a significant difference between the sum of cylinders method and the ellipsoid method in determining relative volume reduction be established. We conclude that a three-dimensional measurement procedure should be used for valid assessments of gallbladder motility. However, according to our data there is no advantage in using the time-consuming sum of cylinders method compared to the simple ellipsoid method.     

对药代动力学实验的两点改进

通过具体的实验数据，讨论在药代动力学实验中如何加入曲线下面积（AUC）的计算，以帮助学生理解并掌握这一概念；在实验室设置不同剂量组，给药后比较剂量与浓度是否呈等比例关系，以此加深学生对于一级动力学消除及其临床意义的理解。     

Oral Valganciclovir Is Noninferior to Intravenous Ganciclovir for the Treatment of Cytomegalovirus Disease in Solid Organ Transplant Recipients

Intravenous ganciclovir is the standard treatment for cytomegalovirus disease in solid organ transplant recipients. Oral valganciclovir is a more convenient alternative. In a randomized, international trial, recipients with cytomegalovirus disease were treated with either 900 mg oral valganciclovir or 5 mg/kg i.v. ganciclovir twice daily for 21 days, followed by 900 mg daily valganciclovir for 28 days. A total of 321 patients were evaluated (valganciclovir [n = 164]; i.v. ganciclovir [n = 157]). The success rate of viremia eradication at Day 21 was 45.1% for valganciclovir and 48.4% for ganciclovir (95% CI -14.0% to +8.0%), and at Day 49; 67.1% and 70.1%, respectively (p = NS). Treatment success, as assessed by investigators, was 77.4% versus 80.3% at Day 21 and 85.4% versus 84.1% at Day 49 (p = NS). Baseline viral loads were not different between groups and decreased exponentially with similar half-lives and median time to eradication (21 vs. 19 days, p = 0.076). Side-effects and discontinuations of assigned treatment (18 of 321 patients) were comparable. Oral valganciclovir shows comparable safety and is not inferior to i.v. ganciclovir for treatment of cytomegalovirus disease in organ transplant recipients and provides a simpler treatment strategy, but care should be taken in extrapolating to organ transplant recipients not properly represented in the present study.