Segmented polymer networks containing amino‐dendrimers

Polymer networks in which poly(propylene imine) dendrimers (Astramol?) are connected to each other by linear polytetrahydrofuran (polyTHF) segments, were prepared by two methods. The first method was a one‐step procedure in which bifunctionally living polyTHF, obtained by initiation of the THF polymerization with trifluoromethane sulfonic anhydride (triflic anhydride), was reacted with an amino‐dendrimer. This reaction was very fast but did not allow formation of the end products. The second method was a two‐step procedure. In a first step, living polyTHF, prepared with acryloyloxybutyl triflate as initiator, was grafted on an amino‐dendrimer, to form a star‐like, acrylate‐terminated polyTHF multi‐macromonomer with the dendrimer as core. In a second step, networks were obtained by Michael addition between the acrylate end‐groups and unreacted amino‐groups of the dendrimer. This cross‐linking reaction occurred spontaneously upon heating of the solution of the multi‐macromonomer with gelation times varying from a few minutes to a few hours, depending on the temperature and the composition of the prepolymers. With this method it was possible to prepare networks in the form of coatings or films. © 2003 Society of Chemical Industry     

Polymer networks based on α,ω-methacrylate-terminated poly(1,3-dioxolane)

α,ω-Methacrylate-terminated poly(1,3-dioxolane)s (polyDXL) were synthesized by cationic ring-opening polymerization of DXL in the presence of methylene-bis(oxyethylmethacrylate) as transfer agent. If the initiator concentration is small compared with the transfer agent concentration, the molecular weights of the polymers are governed by the ratio of the reacted monomer to the reacted transfer agent. The α,ω-methacrylate-terminated polyDXLs obtained undergo free radical polymerization with formation of polyacetal networks. The properties of the networks as function of the molecular weight of the corresponding prepolymers are reported.     

用于制导弹药的自适应自动驾驶仪设计

传统制导弹药自动驾驶仪的设计要求精确的气动模型,并依赖于变增益(gainschedule),以说明系统的非线性.本文给出了一种简化自动驾驶仪设计程序的方法:在单一飞行条件下设计逆控制器,将逆控制器与在线神经网络组合,以说明因近似逆引起的误差,这样减少了大量设计程序及精确的气动数据.这些数据在大攻角或其它情况下很重要,因为这些领域中的空气动力特征变得高度非线性化.研究发现:逆的选择在其实现的过程中很重要,所以详细讨论.最后,给出该方法在非线性6自由度制导弹药中的模拟结果.     

Effect of refraction on optical microscopic measurement of internal blood-vessel diameter and its correction

In optical microscopic measurement of internal blood-vessel diameters, the effect of refraction must be taken into account to ensure accuracy of the result. This effect is discussed and an analytical correction formula derived. Phantom blood vessels with known internal and external diameters were used to test the validity of the correction formula. The errors obtained prior to correction were reduced significantly after correction.     

Reconstitution of CD3 zeta coupling to calcium mobilization via genetic complementation

The integrity of the T cell receptor complex (CD3-TCR) transduction machinery is central to T cell development and to T cell effector function. Molecular dissection of the multimeric CD3-TCR complex revealed that at least two associated polypeptides, CD3 zeta and CD3 epsilon, autonomously couple antigenic recognition event to early and late events of the intracytoplasmic activation cascade. A 18-amino acid motif based on a tandem YXXL stretch, the activation receptor homology sequence 1 (ARH-1) motif, is necessary and sufficient to the transducing properties of both CD3 zeta and CD3 epsilon. Stimulation of chimeric molecules made of ecto- and transmembrane domains of various cell surface proteins and intracytoplasmic domains of CD3 epsilon or CD3 zeta leads to an increase in the intracellular Ca2+ concentration ([Ca2+]i) in Jurkat cells. We describe here that a similar CD25/zeta chimeric molecule was unable to induce a detectable [Ca2+]i rise upon CD25 cross-linking once expressed in the murine thymoma BW-. A Ca2+ influx could, however, be triggered in BW- cells by thapsigargin, i.e. following depletion of Ca2+ stores. Somatic cell hybrids made from BW- and either thymocytes or mature lymph node T cells reconstituted the coupling of CD3 zeta to the Ca2+ signal via an ARH-1 motif-dependent pathway. However, pervanadate-induced Ca2+ mobilization, a phenomenon attributed to tyrosine phosphorylation, was impaired in BW-cells and reconstituted in hybridomas. In contrast to the Ca2+ response, IL-2 production was induced in both BW- and hybrids cells, which questions the functional relevance of [Ca2+]i augmentation in T cell activation. In conclusion, the properties of the BW- thymoma, which define a novel group of CD3 zeta transduction cell mutants, as well as its complementation by somatic cell fusion demonstrate that this cell line represents a useful model to dissect the signaling pathway that couples CD3 zeta to Ca2+ mobilization by genetic reconstitution.     

Ratings of Therapist Dynamic Activities and Alliance Early and Late in Psychotherapy.

The present study examines the concurrent and predictive relationships between therapist psychodynamic-interpersonal activity and therapist-rated alliance. Ratings from 45 patient and therapist dyads engaged in short term psychodynamic psychotherapy from a point early (3rd or 4th session) and late (the session at which 90% of the treatment was completed) in treatment were used. The results suggest that therapists who have positive views of the alliance early in treatment also have positive views of the alliance later in treatment. Therapists who used psychodynamic-interpersonal activities early in treatment also made use of psychodynamic-interpersonal activities later in treatment. Moreover, the use of psychodynamic-interpersonal activities early in treatment was positively related to both global and specific aspects of therapist-rated alliance late in treatment. (PsycINFO Database Record (c) 2011 APA, all rights reserved)