Copolymerization of 5-(trimethylsilyl)norbornene and 5-ethylidene-2-norbornene

Addition and metathesis copolymerization of 5-(trimethylsilyl)norbornene (TMSNB) and 5-ethylidene-2-norbornene (ENB) has been studied. High-molecular-weight metathesis copolymers have been obtained on the first-generation Grubbs catalyst based on the Ru carbene complex Cl₂Ru(=CHPh)(PCy₃)₂ with nearly quantitative yields. Addition copolymerization has been carried out on the Ni(II) naphthenatemethylaluminoxane (MAO) catalytic system. In both cases copolymerization proceeded without participation of ethylidene double bond. Copolymers of this type are promising ones for manufacturing stable highly permeable polymeric membranes, since they are capable for crosslinking.     

The French accelerator mass spectrometry facility ASTER: Improved performance and developments

Following the installation and acceptance test of the French 5 MV AMS facility ASTER, the focus has been on improving the capability for routine measurements of ¹⁰Be and ²⁶Al. Quality assurance has been established by the introduction of traceable AMS standards for each nuclide, by self-monitoring through participation in round-robin exercises and proficiency testing, and by surveillance of long- and short-time variability of blank and reference materials. A background level of 3 × 10^?14 makes ASTER well-suited for measuring ⁴¹Ca/⁴⁰Ca in the10^?12 region, which is sufficient for a wide range of applications. Routine AMS measurements of volatile elements like ³⁶Cl and ¹²⁹I will most likely become feasible in the very near future as the result of significant improvements in the ion source design.     

十大商业失误及对策

失误一:没有注意现金流缺少现金流是造成公司失败的首要原因。许多公司往往因此而中途夭折。可能会葬送一家新公司的问题主要有:·业务增长缺乏足够的资金支持·缺少恰当的记录保存·没有仔细阅读财务报表·对公司资产失去控制·不必要的基础设施     

Apoptosis in HIV-1 Infection

We have studied apoptosis in lymph node and peripheral blood mononuclear cells (PBMCs) from HIV-infected children and adults and SIV-infected rhesus macaques. In lymph nodes, we found that apoptosis and productive infection occurred only rarely in the same cell. There was, however, a direct correlation between the numbers of apoptotic and productively-infected cells. In HIV-infected children, we found a direct correlation between disease severity and percentage CD4+ T cell apoptosis (p = 0.001). Both CD4+ and CD8+ T cell apoptosis were directly related to CD4+ T cell depletion (p = 0.006 and p = 0.01, respectively). In addition, we found a trend towards diminished CD4+ T cell apoptosis on anti-retroviral agents. These findings suggest that apoptosis of uninfected cells may be important in HIV pathogenesis and that measurement of apoptosis may be a useful marker of disease activity.     

Parallelism in alpha-beta search

We present a distributed algorithm for implementing α-β search on a tree of processors. Each processor is an independent computer with its own memory and is connected by communication lines to each of its nearest neighbors. Measurements of the algorithm's performance on the Arachne distributed operating system are presented. A theoretical model is developed that predicts at least order of $\text{k}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ speedup with k processors.     

FDA considerations regarding new hypolipidemic agents

Food and Drug Administration policy being considered for new marketed hypolipidemic agents includes: long-term safety to be demonstrated in postmarketing studies; evidence of clinical effectiveness to be demonstrated within a specified time period. Effectiveness is to be judged by one or more of the following: reduction in xanthomata, reduction in atherosclerotic plaque, reduction in morbidity of coronary artery disease or peripheral and cerebral atherosclerosis, and reduction in mortality. Randomized double blind trials are deemed necessary.     

Fifo nets without order deadlock

Summary We introduce a generalisation of free choice nets to fifo. These fifo nets are free from deadlocks caused by the order of messages in fifo queues. We describe some tools for their analysis, using the fact that they are weakly monotonous, and that there is a narrow relation between their languages and those of the associated coloured nets. Therefore, quasi-liveness, finite termination and liveness are decidable properties.