Genetic effects of 1,3-butadiene and associated risk for heritable damage

A summary of the results of the studies conducted in the EU Project "Multi-endpoint analysis of genetic damage induced by 1,3-butadiene and its major metabolites in somatic and germ cells of mice, rats and man" is presented. Results of the project are summarized on the detection of DNA and hemoglobin adducts, on the cytotoxic and clastogenic effects in somatic and germinal cells of mice and rats, on the induction of somatic mutations at the hprt locus of experimental rodents and occupationally exposed workers, on the induction of dominant lethal mutations in mice and rats, and on heritable translocations induced in mice, after exposure to butadiene (BD) or its major metabolites, butadiene monoepoxide (BMO), diepoxybutane (DEB) and butadiene diolepoxide (BDE). The primary goal of this project was to collect experimental data on the genetic effects of BD in order to estimate the germ cell genetic risk to humans of exposure to BD. To achieve this, the butadiene exposure are based on data for heritable translocations and bone marrow micronuclei induced in mice and chromosome aberrations observed in lymphocytes of exposed workers. A doubling dose for heritable translocations in human germ cells of 4900 ppm/h is estimated, which, assuming cumulative BD exposure over the sensitive period of spermatogenesis, corresponds to 5-6 weeks of continuous exposure at the workplace to 20-25 ppm. Alternatively, the rate of heritable translocation induction per ppm/h of BD exposure is estimated to be approximately 0.8 per million live born, compared to a spontaneous incidence of balanced translocations in humans of approximately 800 per million live born. These estimates have large confidence intervals and are only intended to indicate orders of magnitude of human genetic risk. These risk estimates are based on data from germ cells of BD-exposed male mice. The demonstration that clastogenic damage was induced by DEB in preovulatory oocytes at doses which were not ovotoxic implies that additional studies on the response of mammalian female germ cells to BD and its metabolites are needed. The basic assumption of the above genetic risk estimates is that experimental mouse data obtained after BD exposure can be extrapolated to humans. Several points exist in the present report and in the literature which contradict this assumption: (1) the level of BMO-hemoglobin adducts was significantly elevated in BD-exposed workers; however, it was considerably lower than would have been predicted from comparable rat and mouse exposures; (2) the concentrations of the metabolites DEB and BMO were significantly higher in mouse than in rat blood after BD exposure. Thus, while metabolism of BD is qualitatively similar in the two species, it is quantitatively different; (3) no increase of HPRT mutations was shown in 19 workers exposed on average to 1.8 ppm of BD, while in a different population of workers from a US plant exposed on average to 3.5 ppm of BD, a significant increase of HPRT variants was detected; and (4) data from cancer bioassays and cancer epidemiology suggest that rat is a more appropriate model than mouse for human cancer risk from BD exposure. However, the dominant lethal study in rats gave a negative result. At present, we do not know which BD metabolite(s) may be responsible for the genetic effects even though the bifunctional alkylating agent DEB is the most likely candidate for the induction of clastogenic events. Unfortunately, methods to measure DEB adducts in hemoglobin or DNA are only presently being developed. Despite these several uncertainties the use of the mouse genetic data is regarded as a justifiable and conservative approach to human genetic risk estimation given the considerable heterogeneity observed in the biotransformation of BD in humans.     

The syndrome of depressive depersonalization

Nineteen patients (9 men, 10 women aged 22--38 years) with depressions were examined. The phenomena of anesthesia of ideatoric functions dominated in clinical picture of such depression. This depression is defined as the depression of estrangement. Psychopathologic differentiation of mental estrangement in the structure of depression and in similar disorders of self-consciousness which were formed in depressions under conditions of "transitional syndrome" (according to G.Gross) is outlined. This syndrome is characterised by irreversible negative disorders of "defective depersonalization". The following signs permit to distinguish depression of estrangement from "transitional syndrome": partiality of the estrangement's phenomenon; connection between psychopathologic formations and pathology of imagination (figurative expressiveness, demonstrativity, lability to psychogenic and medical actions); conformity of the syndrome's structure and characteristics of premanifested personality's structure (combination of hyperthymic features with histrionic and/or narcissic ones). "Apperceptive anesthesia" is suggested for designation of the variant of the depression described.     

The Ashkenazic Jewish Bloom syndrome mutation blmAsh is present in non-Jewish Americans of Spanish ancestry

Bloom syndrome (BS) is more frequent in the Ashkenazic Jewish population than in any other. There the predominant mutation, referred to as "blmAsh," is a 6-bp deletion and 7-bp insertion at nucleotide position 2281 in the BLM cDNA. Using a convenient PCR assay, we have identified blmAsh on 58 of 60 chromosomes transmitted by Ashkenazic parents to persons with BS. In contrast, in 91 unrelated non-Ashkenazic persons with BS whom we examined, blmAsh was identified only in 5, these coming from Spanish-speaking Christian families from the southwestern United States, Mexico, or El Salvador. These data, along with haplotype analyses, show that blmAsh was independently established through a founder effect in Ashkenazic Jews and in immigrants to formerly Spanish colonies. This striking observation underscores the complexity of Jewish history and demonstrates the importance of migration and genetic drift in the formation of human populations.     

虚拟MIMO传感器网络中一种联合网络效用和生存时间优化的分布式算法

虚拟(协作式)MIMO技术被认为是传感器网络中有效的节能解决方案之一,然而,现有虚拟MIMO传输策略的设计大多只关注如何有效降低网络能耗,而很少关注反映网络性能的其他指标,例如网络效用(Network Utility),该指标反映了网络数据采集和传输量的多少.为了联合优化网络效用和网络生存时间这两个网络性能参数.本文首先分析虚拟MIMO传输能耗特点,然后基于网络效用最大化(Network Utility Maximization)思想对虚拟MIMO传感器网络进行联合网络生存时间和网络效用的优化建模.在该模型的求解过程中,通过使用对偶分解技术将原需要集中计算的优化问题分解为可以在不同节点上进行计算的子优化问题,并得出一种联合优化网络效用和生存时间的分布式优化算法.该算法的仿真结果显示,网络中的虚拟MIMO节点仅需要交互邻居节点信息,通过有限次的迭代计算,就能收敛到全局最优的发送速率以及功率值.从而使系统总的效用和网络生存时间之间能够达到帕累托(Pareto)最优平衡.     

iDCX 51在Webit上的设计与实现

Webit是一个独立的、低成本的网络服务器,由东大新业技术股份有限公司研制成功.iDCX 51是Intel公司开发的实时操作系统,在工业控制等领域已成功应用,为使其能在Webit中也能够运行,以增强Webit的性能,对此本文以Webit内部单片机AT90S8515为例介绍iDCX 51往Webit中移植的设计与实现,并对移植后的时间性能进行了测试与对比分析,得知其任务切换时间与最大中断禁止时间这两项关键的时间性能指标分别减少33.3%和31.9%,表明系统移植后实时性得到了提高.     

单级倒立摆建模及其控制方法设计

单级倒立摆控制是一个即复杂而又对准确性、快速性要求很高的非线性不稳定系统控制问题。单级倒立摆数学模型的建立对研究其稳定性具有指导作用。用拉格朗日功能平衡法建立了倒立摆的刚体动力学方程,采用了LQR法对其进行了控制设计,并且进行了MATLAB仿真,结果表明此方法均可以成功控制倒立摆,使其稳定并具有良好的鲁棒性。     

Revisiting free riding and the Tit-for-Tat in BitTorrent: A measurement study

In this paper we report new results of our continuous effort on analyzing the impact of incentive mechanisms on user behavior in BitTorrent. In this second measurement and analysis study we find that free riders’ population has significantly increased comparing to our previous measurement study. We relate this increase to the advance in end-users’ connection speeds and to users’ increased knowledge in BitTorrent. We also categorize free riders based on the behavior they exhibit in multiple-torrent system into three types: cheaters, strategic and lucky peers. Furthermore, refuting the findings of other studies, we show that peers who exploit the system in BitTorrent are both high bandwidth capacity peers and low bandwidth capacity peers. Moreover, we argue that the Tit-for-Tat mechanism does not discriminate peers based on their bandwidth capacities and that it reacts successfully against inter-class bandwidth capacity strategic peers. Finally, we propose a memory-backoff approach to the optimistic unchoke policy that reduces the volume of free riding in BitTorrent.

有限字符集信号传输的互信息计算

针对目前有限字符集上衰落信道下的数字通信传输方法无法既简洁又准确地计算互信息值问题,提出了一种新的互信息值计算方法.通过分析对数似然比与互信息之间的关系,对高信噪比和低信噪比两种情况下的简化计算进行加权组合,实现了宽信噪比区间内的低复杂度和准确的互信息值计算.实验结果表明,该算法不仅能够准确地计算互信息值,而且能够简洁、准确地评估无线传输的差错概率.与目前常用算法相比,本文算法具有准确、简便和直观的优势,对数字通信系统性能的理论分析具有较好的指导意义.     

基于ANSYS的汽车排气消声器改进设计

建立消声器的ANSYS仿真模型,分析原消声器的消声性能,通过建立三维仿真模型,研究两腔串联的复杂式结构消声器的消声性能,结果表明,改进后增加了消声器低频带的宽度和中频范围内的消声量,同时稳定高频振荡,但在1 550 Hz和2 300 Hz仍存在问题,加入端部共振腔后,低频段的消声量明显增加,2 300 Hz高频带得到改善.     

Neural basis for the genesis and control of digitalis arrhythmias

The author discussed the increase in the frequency of traumatic paralyses of the ocular muscles, and reported 6 cases of inferior oblique muscle paresis caused by local blunt or sharp traumas (haematoma, contusion, rupture, incarceration) and one case of traumatic Brownian pseudo-paralysis. The localisation of the injuries in 3 cases was on the inferior temporal part and in the other 3 cases on the superior part of the bulbar conjunctiva. Atypical horizontal deviation and characteristic vertical deviation, torsion and torticollis were observed in the majority of cases. One patient recovered spontaneously. 3 patients became asymptomatic after correction by prisms and one after recession of contralateral superior rectus muscle. The symptoms remained unchanged in the case of a "blow out" fracture (in spite of operation) and a Brown's syndrome (without treatment).