污水土地处理生态工程综合效益评价以霍林河森林型慢速渗滤土地处理工程为例

为了科学、定量地评价污水土地处理生态工程的综合效益,运用层次分析法（ＡＨＰ）,提出了评价指标体系、指标权重和综合效益计算方法．应用此方法对霍林河森林型慢速渗滤土地处理工程的综合效益进行了分析与评价．结果表明,霍林河森林型慢速渗滤土地处理工程的综合效益值ＣＥ＝０．６４,属于中级生态经济系统,而且具有良好的环境效益和社会效益     

Optimal stimulation frequency for vibrational optical coherence elastography

Vibrational optical coherence elastography (OCE) is a promising tool for extracting the mechanical property of soft tissue. Purpose of this study is focusing on settling the optimal frequency range for vibrational OCE with evenly distributed stress filed. A finite element model of 2% agar phantom was built by ANSYS with a vibration stimulation frequency range from 200 to 3000 Hz. Practical experiments were carried out for cross‐validation with the same frequencies and sample. Lateral and horizontal stress filed distributions under different frequencies were mathematically evaluated by coefficient of variance and degree of linearity. Results from simulation and practical experiment cross‐validated each other and 1000 Hz was set as the maximum ideal frequency for vibrational OCE, while the minimum frequency is set by theoretical calculation with a result of 250 Hz. An ex vivo biological sample was utilised to testify performance of vibrational OCE with excitation frequencies in and out of concluded optimal range, which showed that stiffness was better mapped out in optimal frequency range.     

Methylation protects miRNAs and siRNAs from a 3'-end uridylation activity in Arabidopsis

Small RNAs of 21-25 nucleotides (nt), including small interfering RNAs (siRNAs) and microRNAs (miRNAs), act as guide RNAs to silence target-gene expression in a sequence-specific manner. In addition to a Dicer homolog, DCL1, the biogenesis of miRNAs in Arabidopsis requires another protein, HEN1. miRNAs are reduced in abundance and increased in size in hen1 mutants. We found that HEN1 is a miRNA methyltransferase that adds a methyl group to the 3'-most nucleotide of miRNAs, but the role of miRNA methylation was unknown. Here, we show that siRNAs from sense transgenes, hairpin transgenes, and transposons or repeat sequences, as well as a new class of siRNAs known as trans-acting siRNAs, are also methylated in vivo by HEN1. In addition, we show that the size increase of small RNAs in the hen1-1 mutant is due to the addition of one to five U residues to the 3' ends of the small RNAs. Therefore, a novel uridylation activity targets the 3' ends of unmethylated miRNAs and siRNAs in hen1 mutants. We conclude that 3'-end methylation is a common step in miRNA and siRNA metabolism and likely protects the 3' ends of the small RNAs from the uridylation activity.     

Phosphorylation on tyrosine-15 of p34(Cdc2) by ErbB2 inhibits p34(Cdc2) activation and is involved in resistance to taxol-induced apoptosis

ErbB2 overexpression confers resistance to taxol-induced apoptosis by inhibiting p34(Cdc2) activation. One mechanism is via ErbB2-mediated upregulation of p21(Cip1), which inhibits Cdc2. Here, we report that the inhibitory phosphorylation on Cdc2 tyrosine (Y)15 (Cdc2-Y15-p) is elevated in ErbB2-overexpressing breast cancer cells and primary tumors. ErbB2 binds to and colocalizes with cyclin B-Cdc2 complexes and phosphorylates Cdc2-Y15. The ErbB2 kinase domain is sufficient to directly phosphorylate Cdc2-Y15. Increased Cdc2-Y15-p in ErbB2-overexpressing cells corresponds with delayed M phase entry. Expressing a nonphosphorylatable mutant of Cdc2 renders cells more sensitive to taxol-induced apoptosis. Thus, ErbB2 membrane RTK can confer resistance to taxol-induced apoptosis by directly phosphorylating Cdc2.     

Generation and Analysis of ESTs from the Grass Carp,Ctenopharyngodon idellus

Grass carp, Ctenopharyngodon idellus (Valenciennes, 1844), is an economically important species widely cultured in the world, but its genome research resources are largely lacking. The objectives of this study were to construct normalized cDNA libraries for efficient EST analysis, to generate ESTs from these libraries, and to identify EST-related molecular markers such as microsatellites and single nucleotide polymorphisms (SNPs) for genetic analysis of this species. A total of 6,269 ESTs were generated representing 4,815 unique sequences, from which 105 putative microsatellites and 5,228 SNPs were identified. These genome resources provide the material basis for future genetic and functional analyses in this species.     

Comparative cardiac mechanics: Laplace's Law

The pumping ability of the heart is determined by mechanical and geometrical factors. These latter are governed by Laplace's Law. The extent of the applicability of this law across mammalian species is examined utilizing allometric relations and dimensional analysis. Results show that Laplace's Law plays an important role in linking the anatomical design to the functional capability of mammalian hearts.     

PNAS-4 expression and its relationship to p53 in colorectal cancer

PNAS-4 is a novel pro-apoptotic protein activated during the early response to DNA damage; however, the molecular mechanisms and pathways regulating PNAS-4 expression in tumors are not well understood. We hypothesized that PNAS-4 is a p53 down-stream target gene and designed this study. We searched online for putative p53-binding sites in the entire PNAS-4 gene and did not find any corresponding information. In HCT116 colon cancer cells, after being transfected with small interfering RNA to silence p53, the expressions of PNAS-4 and other known p53 target gene (Apaf1, Bax, Fas and Dr5) were determined by real-time PCR. We found that PNAS-4 was up-regulated while Apaf1, Bax, Fas and Dr5 were down-regulated. We then examined the expression of PNAS-4 and p53 mutation in colorectal cancer patients. PNAS-4 expressed both in colorectal cancers and normal tissues, but compared with paired control, PNAS-4 was up-regulated in cancers (P = 0.018). PNAS-4 overexpression ratios were correlated to the p53 mutant status (P = 0.001). The mean PNAS-4 expression levels of p53 mutant homozygote group and heterozygote group were higher than that of p53 wild type group (P = 0.013). The expression ratios of PNAS-4 (every sample in relative to its paired normal mucosa) were different between negative lymph node metastasis (66% up-regulated, 34% down-regulated) and positive metastasis (42% up-regulated, 58% down-regulated). Taken together, these findings suggested that PNAS-4 was not a p53 target, but overexpression of PNAS-4 was correlated to p53 inactivity in colorectal cancer.