宽带CDMA蜂窝系统中小区容量和覆盖半径的计算

在功率控制方程中加入干扰因子后,推导了中断概率,基站接收机灵敏度,移动台最大可允许的发射功率,信干比的期望值,路径抽耗与小区覆盖半径,小区容量的关系式,在2GHz频率,宽带,各种速率时,计算了基站接收信号的信干比,小区容量和小区的覆盖半径。     

Oncogene-induced senescence is part of the tumorigenesis barrier imposed by DNA damage checkpoints

Recent studies have indicated the existence of tumorigenesis barriers that slow or inhibit the progression of preneoplastic lesions to neoplasia. One such barrier involves DNA replication stress, which leads to activation of the DNA damage checkpoint and thereby to apoptosis or cell cycle arrest, whereas a second barrier is mediated by oncogene-induced senescence. The relationship between these two barriers, if any, has not been elucidated. Here we show that oncogene-induced senescence is associated with signs of DNA replication stress, including prematurely terminated DNA replication forks and DNA double-strand breaks. Inhibiting the DNA double-strand break response kinase ataxia telangiectasia mutated (ATM) suppressed the induction of senescence and in a mouse model led to increased tumour size and invasiveness. Analysis of human precancerous lesions further indicated that DNA damage and senescence markers cosegregate closely. Thus, senescence in human preneoplastic lesions is a manifestation of oncogene-induced DNA replication stress and, together with apoptosis, provides a barrier to malignant progression.     

一类新型多氟氮超酸锂盐电解液的性质研究

合成了一类新型多氟氮超酸锂金属盐──二（多氟烷氧基）磺酰基氨化锂，ＬｉＮ（ＳＯ２ＯＲｆ）２（Ｒｆ＝－ＣＨ２ＣＦ３，－ＣＨ２ＣＦ２ＣＦ３，－ＣＨ３ＣＦ２ＣＦ２Ｈ，－ＣＨ（ＣＦ３）２），并用ＩＲ，１ＨＮＭＲ，１９ＦＮＭＲ对它们的结构进行了表征．以碳酸丙烯酯（ＰＣ）和乙二醇二甲醇（ＤＭＥ）为混合溶剂，研究了由这些锂盐组成的电解液的性质．结果显示，新型氟氮超酸锂盐的电化学性能十分优良，可以满足锂电池电解液的要求．讨论了引入不同的取代基所导致的对溶液导电性和阳极抗氧化性能的影响．     

CD38 is critical for social behaviour by regulating oxytocin secretion

CD38, a transmembrane glycoprotein with ADP-ribosyl cyclase activity, catalyses the formation of Ca2+ signalling molecules, but its role in the neuroendocrine system is unknown. Here we show that adult CD38 knockout (CD38-/-) female and male mice show marked defects in maternal nurturing and social behaviour, respectively, with higher locomotor activity. Consistently, the plasma level of oxytocin (OT), but not vasopressin, was strongly decreased in CD38-/- mice. Replacement of OT by subcutaneous injection or lentiviral-vector-mediated delivery of human CD38 in the hypothalamus rescued social memory and maternal care in CD38-/- mice. Depolarization-induced OT secretion and Ca2+ elevation in oxytocinergic neurohypophysial axon terminals were disrupted in CD38-/- mice; this was mimicked by CD38 metabolite antagonists in CD38+/+ mice. These results reveal that CD38 has a key role in neuropeptide release, thereby critically regulating maternal and social behaviours, and may be an element in neurodevelopmental disorders.     

文明戏(中国早期话剧)研究史的几个问题——以袁国兴和黄爱华近著为中心

近几年相继出版的袁国兴的《中国话剧的孕育与生成》和黄爱华的《中国早期话剧与日本》,是两部各有特色的文明戏研究专著,有体系的专门研究论著的出版,无疑标志着中国国内的文明戏研究达到了一个新的阶段。通过对文明戏研究现状和存在问题的考察,可知今后的文明戏研究方向应该是:一、加强戏剧史料的整理和研究,只有依靠正确的资料,才能期望文明戏研究有新的成果产生;二、加强中日学术交流,以解决中国学者对日本戏剧知识不足的问题;三、加强文明戏与中国传统戏曲以及早期电影的关系的研究,以更全面深入地认识和把握文明戏的特性。     

A synaptic laminin-calcium channel interaction organizes active zones in motor nerve terminals

Synapse formation requires the differentiation of a functional nerve terminal opposite a specialized postsynaptic membrane. Here, we show that laminin beta2, a component of the synaptic cleft at the neuromuscular junction, binds directly to calcium channels that are required for neurotransmitter release from motor nerve terminals. This interaction leads to clustering of channels, which in turn recruit other presynaptic components. Perturbation of this interaction in vivo results in disassembly of neurotransmitter release sites, resembling defects previously observed in an autoimmune neuromuscular disorder, Lambert-Eaton myasthenic syndrome. These results identify an extracellular ligand of the voltage-gated calcium channel as well as a new laminin receptor. They also suggest a model for the development of nerve terminals, and provide clues to the pathogenesis of a synaptic disease.     

Evidence from massive siderite beds for a CO2-rich atmosphere before approximately 1.8 billion years ago

It is generally thought that, in order to compensate for lower solar flux and maintain liquid oceans on the early Earth, methane must have been an important greenhouse gas before approximately 2.2 billion years (Gyr) ago. This is based upon a simple thermodynamic calculation that relates the absence of siderite (FeCO3) in some pre-2.2-Gyr palaeosols to atmospheric CO2 concentrations that would have been too low to have provided the necessary greenhouse effect. Using multi-dimensional thermodynamic analyses and geological evidence, we show here that the absence of siderite in palaeosols does not constrain atmospheric CO2 concentrations. Siderite is absent in many palaeosols (both pre- and post-2.2-Gyr in age) because the O2 concentrations and pH conditions in well-aerated soils have favoured the formation of ferric (Fe3+)-rich minerals, such as goethite, rather than siderite. Siderite, however, has formed throughout geological history in subsurface environments, such as euxinic seas, where anaerobic organisms created H2-rich conditions. The abundance of large, massive siderite-rich beds in pre-1.8-Gyr sedimentary sequences and their carbon isotope ratios indicate that the atmospheric CO2 concentration was more than 100 times greater than today, causing the rain and ocean waters to be more acidic than today. We therefore conclude that CO2 alone (without a significant contribution from methane) could have provided the necessary greenhouse effect to maintain liquid oceans on the early Earth.     

Insect signalling: components of giant hornet alarm pheromone

Up to 74 people die each year in Japan after being stung by Hymenopteran insects, with hornets (Vespa spp.) being among the worst offenders. Here we identify a volatile, multi-component alarm pheromone in the venom of the world's largest hornet, V. mandarinia, and use field bioassays to show that 2-pentanol is its principal active component, and that 3-methyl-1-butanol and 1-methylbutyl 3-methylbutanoate act synergistically with it. The compound 1-methylbutyl 3-methylbutanoate, which may also be a foraging-site-marking pheromone, elicits a strong defensive reaction in the sympatric prey hornet V. simillima xanthoptera. As these chemicals are sometimes used in food flavourings and as fragrances in cosmetics, it is possible that they might provoke a seemingly unwarranted hornet attack on humans.