五台山风景区生态旅游发展阶段研究

五台山风景区拥有丰富的生态旅游资源,生态旅游发展迅速。根据旅游地生命周期理论,结合五台山风景区生态旅游发展现状,分析五台山风景区生态旅游所处的发展阶段,并分析此阶段风景区存在的问题,提出解决对策,为五台山风景区今后的发展指出明确方向。     

分布式结构及其使用技术的研究

研究分布式结构的相关理论，给出分布式结构的涵义，讨论分布式结构的优点与商业效益，并研究分布式结构所使用的技术要点．     

Identification of a bacterial inhibitor against g-type lysozyme

Lysozymes are antibacterial effectors of the innate immune system in animals that hydrolyze peptidoglycan. Bacteria have evolved protective mechanisms that contribute to lysozyme tolerance such as the production of lysozyme inhibitors, but only inhibitors of chicken (c-) and invertebrate (i-) type lysozyme have been identified. We here report the discovery of a novel Escherichia coli inhibitor specific for goose (g-) type lysozymes, which we designate PliG (periplasmic lysozyme inhibitor of g-type lysozyme). Although it does not inhibit c- or i-type lysozymes, PliG shares a structural sequence motif with the previously described PliI and MliC/PliC lysozyme inhibitor families, suggesting a common ancestry and mode of action. Deletion of pliG increased the sensitivity of E. coli to g-type lysozyme. The existence of inhibitors against all major types of animal lysozyme and their contribution to lysozyme tolerance suggest that lysozyme inhibitors may play a role in bacterial interactions with animal hosts.     

地方政府官员微博在化解社会矛盾中的作用及实现

地方政府官员微博在化解社会矛盾中发挥了重要的作用,其有助于地方政府官员回应民众诉求;有利于化解因信息不通造成的社会恐慌;有助于拉近官民距离;有利于塑造政府形象;有利于降低突发事件的不良影响或者减少突发事件的发生,维护社会稳定。但是也有失误的教训,某些官员对微博认识不充分,微博形式大过内容,娱乐大过务实,部分官员对自身角色定位不准,缺少监督管理等,在涉及危机公关、化解社会矛盾等方面,微博没有发挥应有的作用。地方政府官员微博有效化解社会矛盾的途径是,微博定位要准确,克服形式主义,完善相关法律法规,规范言论自由,加强地方政府官员的媒介素养教育等。     

Molecular basis of parathyroid hormone receptor signaling and trafficking: a family B GPCR paradigm

The parathyroid hormone (PTH) receptor type 1 (PTHR), a G protein-coupled receptor (GPCR), transmits signals to two hormone systems—PTH, endocrine and homeostatic, and PTH-related peptide (PTHrP), paracrine—to regulate different biological processes. PTHR responds to these hormonal stimuli by activating heterotrimeric G proteins, such as G_S that stimulates cAMP production. It was thought that the PTHR, as for all other GPCRs, is only active and signals through G proteins on the cell membrane, and internalizes into a cell to be desensitized and eventually degraded or recycled. Recent studies with cultured cell and animal models reveal a new pathway that involves sustained cAMP signaling from intracellular domains. Not only do these studies challenge the paradigm that cAMP production triggered by activated GPCRs originates exclusively at the cell membrane but they also advance a comprehensive model to account for the functional differences between PTH and PTHrP acting through the same receptor.     

浅谈软交换在通信行业中的应用

电信运营商目前面临的网络资源紧张是一个迫切需要解决的问题,软交换的应运而生将带来网络结构扁平化的变革,从而较好地解决网络资源这一问题。简要介绍了软交换系统的特点,探讨了软交换在山西联通骨干网中的应用和存在的问题。     

An improved 3-D ray tracing method using linear traveltime interpolation

An approach of three-dimensional seismic ray tracing is presented, which is derived from adopting two-dimensional linear traveltime interpolation (LTI). By adjusting the forward process using the partition of grid interface, and backward step by considering more directions, the new approach is suitable for the application of three-dimensional models. The calculation results show that, with the same accuracy, the improved 3-D method is much faster than the method of traditional LTI directly applied in the three-dimensional case.     

Language clusters based on linguistic complex networks

To investigate the feasibility of using complex networks in the study of linguistic typology, this paper builds and explores 15 lin-guistic complex networks based on the dependency syntactic treebanks of 15 languages. The results show that it is possible to classify human languages by means of the following main parameters of complex networks: (a) average degree of the node, (b) cluster coefficients, (c) average path length, (d) network centralization, (e) diameter, (f) power exponent of degree distribution, and (g) the determination coefficient of power law distributions. The precision of this method is similar to the results achieved by means of modern word order typology. This paper tries to solve two problems of current linguistic typology. First, the language sample of a typological study is not real text; second, typological studies pay too much attention to local language structures in the course of choosing typological parameters. This study performs better in global typological features of language and not only enhances typological methods, but it is also valuable for developing the applications of complex networks in the humanities, social, and life sciences.     

Prediction of sites under adaptive evolution in flavin-containing monooxygenases: Selection pattern revisited

Flavin-containing monooxygenase (FMO), like cytochrome P450 (CYP), is a monooxygenase that uses the reducing equivalents of NADPH to reduce one atom of molecular oxygen to water, while the other atom is used to oxidize the substrate. Recently, it was shown that some CYP isoforms have been subject to positive selection. However, it is unknown whether the highly conserved phase I detoxification enzyme, FMO, has undergone similar positive Darwinian selection. We used maximum-likelihood models of codon substitution, evolutionary fingerprinting, and cross species comparison to investigate the occurrence of adaptive evolution in FMO sequences. We used recent genomic data from a range of species, including vertebrates and invertebrates. We present the evidence for the occurrence of adaptive evolution in mammalian FMO 3, 4, 5, and fugu FMOs but not in mammalian FMO 1, FMO 2, frog FMOs, other fish FMOs and invertebrate FMOs. The sites under adaptive evolution were significantly associated with the insertion domain in mammalian FMO 5. We identified specific amino acid sites in FMOs 3–5 that are likely targets for selection based on the patterns of parallel amino acid change. The most likely role of adaptive evolution is the repair of mutations that permitted optimal NADP+ binding and improved catalytic efficiency. The occurrence of positive selection during the evolution of phase I detoxification enzymes such as FMOs 3–5 and fugu FMO suggests the occurrence of both high selection pressure acting on species within their unique habitats and significant changes in intensity and direction (forms of xenobiotics and drugs) resulting from changes in microhabitat and food.     

Plasmonic biosensors and nanoprobes based on gold nanoshells

Gold nanoshells (GNSs), consisting of a dielectric core coated with gold, have gained extensive attention as they show readily tunable optical properties and good biocompatibility. As highly sensitive and label-free optical biosensors with wide applications, GNSs have been investigated in many fields including drug delivery, immunoassay, cancer treatment, biological sensing and imaging. Taking advantage of the adjustability of the local surface plasmon resonance (LSPR) and the sensitivity of the surfaceenhanced Raman scattering (SERS) signal of GNSs, we have developed diverse applications including plasmonic biosensors and nanoprobes based on GNSs. In this review we introduce plasmonic and electromagnetic properties and fabrication methods of GNSs. We describe research progress in recent years, and highlight several applications of GNSs developed by our group. Finally we provide a brief assessment of future development of GNSs as plasmonic materials that can be integrated with complementary analytical techniques.