硝化-反硝化生物滤器处理城市污水的启动和运行效果

实验室废水处理反应器处理实际城市污水运行75 d .主要系统为包含两部份的上流式生物滤器.生物滤器上部曝气,用于硝化;下部缺氧,用于反硝化.为了避免自养硝化菌和异养微生物的竞争,采用新式间接启动方法实现硝化仅用时两周.该生物滤器在室温下运行,溶解于水中总有机碳(DOC)的去除率可达到75 %,总固体悬浮物的去除率可达88·5 %,总氨氮和总氮可分别去除94 %和60 %.     

Structural comparisons of isomorphic breeding nests between closely allied spiders Cheiracanthium japonicum and Cheiracanthium lascivum (Araneae: Eutichuridae)

Closely allied spider species Cheiracanthium japonicum and Cheiracanthium lascivum make a closed breeding nest for egg laying and parental care. The nest provides the internal climatic stability required for suitable development of eggs and the physical durability required for protection against intruders. Although the breeding nests of these two spiders are quite similar in structure and appearance, their climatic stability and physical durability seem to be empirically different. Such physical features of the nests of these two spiders were compared based on a balance between the inner and outer air temperature and humidity of the nest as well as on the amount and size of spider silks lining the nest. In addition, the female’s relative energy allocation to egg production versus nest construction was examined based on the number or weight of eggs versus the climatic stability and physical durability of the nest. According to the results, the stability of temperature and humidity was maintained better in the breeding nest of C. japonicum than in that of C. lascivum. Furthermore, the nest of C. japonicum was more strongly constructed, with a greater volume and size of silks, than that of C. lascivum. On the other hand, the number or weight of eggs in relation to the female’s body weight in C. japonicum was smaller than that in C. lascivum. These results suggested that the reproductive effort towards nest construction for the purpose of egg and juvenile care in C. japonicum was larger than that in C. lascivum. In contrast, the effort towards egg production in C. japonicum was smaller than that in C. lascivum. Consequently, it is likely that the structural differences in breeding nests between these two spiders are responsible for the discrepancies in the female’s relative energy allocation to nest construction.     

Crystal structure of the human centromeric nucleosome containing CENP-A

In eukaryotes, accurate chromosome segregation during mitosis and meiosis is coordinated by kinetochores, which are unique chromosomal sites for microtubule attachment. Centromeres specify the kinetochore formation sites on individual chromosomes, and are epigenetically marked by the assembly of nucleosomes containing the centromere-specific histone H3 variant, CENP-A. Although the underlying mechanism is unclear, centromere inheritance is probably dictated by the architecture of the centromeric nucleosome. Here we report the crystal structure of the human centromeric nucleosome containing CENP-A and its cognate α-satellite DNA derivative (147 base pairs). In the human CENP-A nucleosome, the DNA is wrapped around the histone octamer, consisting of two each of histones H2A, H2B, H4 and CENP-A, in a left-handed orientation. However, unlike the canonical H3 nucleosome, only the central 121 base pairs of the DNA are visible. The thirteen base pairs from both ends of the DNA are invisible in the crystal structure, and the αN helix of CENP-A is shorter than that of H3, which is known to be important for the orientation of the DNA ends in the canonical H3 nucleosome. A structural comparison of the CENP-A and H3 nucleosomes revealed that CENP-A contains two extra amino acid residues (Arg?80 and Gly?81) in the loop 1 region, which is completely exposed to the solvent. Mutations of the CENP-A loop 1 residues reduced CENP-A retention at the centromeres in human cells. Therefore, the CENP-A loop 1 may function in stabilizing the centromeric chromatin containing CENP-A, possibly by providing a binding site for trans-acting factors. The structure provides the first atomic-resolution picture of the centromere-specific nucleosome.     

嵌入期权的激励相容型软件外包付款合同设计

扩展了文献[1]的经典模型, 建立起激励相容框架下软件外包付款合同设计的正式模型. 特别之处在于嵌入了一个中期检查的触发期权, 在模型中采用示性函数的方法简洁表示. 通过基准模型与嵌入触发期权的模型结果的比较, 证明了嵌入触发期权对外包的风险控制、促进承接商(vendor)提高努力程度均占有优势. 还发现嵌入期权对客户(client)与承接商的双重约束功能, 主要通过改变超支分担系数来约束客户行为. 利用中国对日本的软件外包承接商的调查研究数据, 证实了嵌入触发期权主要通 过促进承接商超支控制效率的提高而实现外包风险有效控制,也证实了双重约束功能及其他主要理论结果.     

Meta-analysis of genome-wide association studies identifies eight new loci for type 2 diabetes in east Asians

We conducted a three-stage genetic study to identify susceptibility loci for type 2 diabetes (T2D) in east Asian populations. We followed our stage 1 meta-analysis of eight T2D genome-wide association studies (6,952 cases with T2D and 11,865 controls) with a stage 2 in silico replication analysis (5,843 cases and 4,574 controls) and a stage 3 de novo replication analysis (12,284 cases and 13,172 controls). The combined analysis identified eight new T2D loci reaching genome-wide significance, which mapped in or near GLIS3, PEPD, FITM2-R3HDML-HNF4A, KCNK16, MAEA, GCC1-PAX4, PSMD6 and ZFAND3. GLIS3, which is involved in pancreatic beta cell development and insulin gene expression, is known for its association with fasting glucose levels. The evidence of an association with T2D for PEPD and HNF4A has been shown in previous studies. KCNK16 may regulate glucose-dependent insulin secretion in the pancreas. These findings, derived from an east Asian population, provide new perspectives on the etiology of T2D.     

SNPs in KCNQ1 are associated with susceptibility to type 2 diabetes in East Asian and European populations

We conducted a genome-wide association study using 207,097 SNP markers in Japanese individuals with type 2 diabetes and unrelated controls, and identified KCNQ1 (potassium voltage-gated channel, KQT-like subfamily, member 1) to be a strong candidate for conferring susceptibility to type 2 diabetes. We detected consistent association of a SNP in KCNQ1 (rs2283228) with the disease in several independent case-control studies (additive model P = 3.1 x 10(-12); OR = 1.26, 95% CI = 1.18-1.34). Several other SNPs in the same linkage disequilibrium (LD) block were strongly associated with type 2 diabetes (additive model: rs2237895, P = 7.3 x 10(-9); OR = 1.32, 95% CI = 1.20-1.45, rs2237897, P = 6.8 x 10(-13); OR = 1.41, 95% CI = 1.29-1.55). The association of these SNPs with type 2 diabetes was replicated in samples from Singaporean (additive model: rs2237895, P = 8.5 x 10(-3); OR = 1.14, rs2237897, P = 2.4 x 10(-4); OR = 1.22) and Danish populations (additive model: rs2237895, P = 3.7 x 10(-11); OR = 1.24, rs2237897, P = 1.2 x 10(-4); OR = 1.36).     

On network-based kernel methods for protein-protein interactions with applications in protein functions prediction

Predicting protein functions is an important issue in the post-genomic era. This paper studies several network-based kernels including local linear embedding (LLE) kernel method, diffusion kernel and laplacian kernel to uncover the relationship between proteins functions and protein-protein interactions (PPI). The author first construct kernels based on PPI networks, then apply support vector machine (SVM) techniques to classify proteins into different functional groups. The 5-fold cross validation is then applied to the selected 359 GO terms to compare the performance of different kernels and guilt-by-association methods including neighbor counting methods and Chi-square methods. Finally, the authors conduct predictions of functions of some unknown genes and verify the preciseness of our prediction in part by the information of other data source.