学科馆员——图书馆员的新追求

从发挥图书馆职能入手，阐述了学科馆员产生的必要性，通过对学科馆员的概念内涵、岗位职责、与传统参考馆员比较及我国高校图书馆学科馆员现状的分析，探讨了如何才能做好学科馆员，为读者提供优质服务。     

水色遥感理论模型探讨

由于目前技术条件的限制 ,黑箱模型在水体组份反演的研究中占据了主导地位 ,但其理论基础不足 ,针对具体成像条件推得的黑箱模型难以推广 ,故需从水色遥感成像机理出发来研究理论模型的识别和求解。意识到辐射传输方程难以实用 ,提出基于辐射传输方程求解结论的水色遥感理论模型架构。并讨论了模型的若干影响因素。特别指出 ,应该使用传感器灵敏度积分的方法来关联传感器接收到的辐射率和灰度值数据 ,而不是简单地使用传感器在波段中心波长处接收的辐射率。     

随机多址访问协议中最优帧模式的混合遗传算法

在随机接入协议中 ,竞争时隙与预约时隙在一帧中的相对位置 (帧模式 )对系统的吞吐量有很大的影响 .利用混合遗传算法搜索出不同业务量下的最优帧模式 ,提高了系统的吞吐量 .     

Mutations in a human homologue of Drosophila crumbs cause retinitis pigmentosa (RP12).

Retinitis pigmentosa (RP) comprises a clinically and genetically heterogeneous group of diseases that afflicts approximately 1.5 million people worldwide. Affected individuals suffer from a progressive degeneration of the photoreceptors, eventually resulting in severe visual impairment. To isolate candidate genes for chorioretinal diseases, we cloned cDNAs specifically or preferentially expressed in the human retina and the retinal pigment epithelium (RPE) through a novel suppression subtractive hybridization (SSH) method. One of these cDNAs (RET3C11) mapped to chromosome 1q31-q32.1, a region harbouring a gene involved in a severe form of autosomal recessive RP characterized by a typical preservation of the para-arteriolar RPE (RP12; ref. 3). The full-length cDNA encodes an extracellular protein with 19 EGF-like domains, 3 laminin A G-like domains and a C-type lectin domain. This protein is homologous to the Drosophila melanogaster protein crumbs (CRB), and denoted CRB1 (crumbs homologue 1). In ten unrelated RP patients with preserved para-arteriolar RPE, we identified a homozygous AluY insertion disrupting the ORF, five homozygous missense mutations and four compound heterozygous mutations in CRB1. The similarity to CRB suggests a role for CRB1 in cell-cell interaction and possibly in the maintenance of cell polarity in the retina. The distinct RPE abnormalities observed in RP12 patients suggest that CRB1 mutations trigger a novel mechanism of photoreceptor degeneration.     

An Experimental Study of Aspect Ratio on the Tensile Properties of an Elastic Fabric for Making-up of Pressure Garments

The“cut-and-sewn” pressure garments are normally tailored made in various sizes according to the size of human body as well as the area of burn wounds.When a tubular pressure garment is cut in different length and width measurements,different aspect ratio will be occurred on the elastic fabric for making up the pressuregarment. Many therapists in Hong Kong concerned the change of aspect ratio may affect the tensile properties of the elastic fabric and ultimately will affect the skin-and-garment interface pressure for the patient.The aim of     

Trail-following responses ofLeptogenys diminuta to stereoisomers of 4-methyl-3-heptanol

Behavioral tests carried out with the four stereoisomers of 4-methyl-3-heptanol revealed thatLeptogenys diminuta ants respond specifically only to the (3R, 4S)-isomer.     

Small nuclear ribonucleoprotein polypeptide N (SNRPN), an expressed gene in the Prader-Willi syndrome critical region.

Prader-Willi syndrome (PWS) is associated with paternally derived chromosomal deletions in region 15q11-13 or with maternal disomy for chromosome 15. Therefore, loss of the expressed paternal alleles of maternally imprinted genes must be responsible for the PWS phenotype. We have mapped the gene encoding the small nuclear RNA associated polypeptide SmN (SNRPN) to human chromosome 15q12 and a processed pseudogene SNRPNP1 to chromosome region 6pter-p21. Furthermore, SNRPN was mapped to the minimal deletion interval that is critical for PWS. The fact that the mouse Snrpn gene is maternally imprinted in brain suggests that loss of the paternally derived SNRPN allele may be involved in the PWS phenotype.     

Successive action of DnaK, DnaJ and GroEL along the pathway of chaperone-mediated protein folding.

The main stress proteins of Escherichia coli function in an ordered protein-folding reaction. DnaK (heat-shock protein 70) recognizes the folding polypeptide as an extended chain and cooperates with DnaJ in stabilizing an intermediate conformational state lacking ordered tertiary structure. Dependent on GrpE and ATP hydrolysis, the protein is then transferred to GroEL (heat-shock protein 60) which acts catalytically in the production of the native state. This sequential mechanism of chaperone action may represent an important pathway for the folding of newly synthesized polypeptides.     

Bazooka provides an apical cue for Inscuteable localization in Drosophila neuroblasts

Asymmetric cell division generates daughter cells with different developmental fates from progenitor cells that contain localized determinants. During this division, the asymmetric localization of cell-fate determinants and the orientation of the mitotic spindle must be precisely coordinated. In Drosophila neuroblasts, inscuteable controls both spindle orientation and the asymmetric localization of the cell-fate determinants Prospero and Numb. Inscuteable itself is localized in an apical cortical crescent and thus reflects the intrinsic asymmetry of the neuroblast. Here we show that localization of Inscuteable depends on Bazooka, a protein containing three PDZ domains with overall sequence similarity to Par-3 of Caenorhabditis elegans. Bazooka and Inscuteable form a complex that also contains Staufen, a protein responsible for the asymmetric localization of prospero messenger RNA. We propose that, after delamination of the neuroblast from the neuroepithelium, Bazooka provides an asymmetric cue in the apical cytocortex that is required to anchor Inscuteable. As Bazooka is also responsible for the maintenance of apical-basal polarity in epithelial tissues, it may be the missing link between epithelial polarity and neuroblast polarity.