CCD相机的BUCK-BOOST型稳压电源设计

根据CCD工作过程及其耗能特点,应用BUCK-BOOST开关稳压控制器LCT3780控制的级联式双向BUCK-BOOST电路,设计了一款针对CCD相机的高性能稳压电源。利用LTspice仿真软件对开关稳压电路进行了仿真,主要对不同输入电压时的输出电压和有大突变负载时的稳压能力进行了仿真,并通过实验进行了测试。

高产、优质、多抗棉花品种鄂棉15的选育

高产、优质、多抗棉花鄂棉１５系用Ｃｏ６０－γ射线３．０万伦琴辐射河南７５选育而成，是国内第一个种植面积逾７万ｈｍ２的辐射育成的林花新品种。正确这择基础材料；采用高剂量辐射；利用生物统计方法重点选择微突变，兼顾大突变；依据理想株型，将自然选择与人工选择有机结合，提高选择强度；进行早代测定，越级参加品系比较试验。边试验，边选择，边繁殖，边采用“选株自交，分系比较，严格鉴定，常态选择”的方法生产育种家种子，加快了育种进程，提高了种植鄂棉１５的经济效益和社会效益。

Grain Filling Characteristics of Giant Embryo Rice Mutant

[Objective] The aim was to explore the relevance between decreased 1 000-grain weight and grain-filling characteristics of rice giant embryo mutant.[Method] Richards equation was used to describe grain filling processes of giant embryo mutant MH-ge1 and its corresponding wild type so as to analyze the parameters of grain-filling characteristics of materials.[Result] The initial filling power of mutant MH-ge1 was higher than the wild type MH86,however,the maximum filling rate,the mean filling rate and the final increment of mutant MH-ge1 was lower than those of MH86.[Conclusion] The grain-filling characteristics of mutant MH-ge1 were poorer than the wild type MH86,thus resulting in the decrease of the grain weight of the giant embryo rice.

马克思主义统一战线学说的研究对象

马克思主义统一战线原理如实地将研究对象作为不断变化发展的事物.将社会中一切物质和精神的力量都作为反对以一成不变的眼光看待这些对象的教条主义和机械论,因其无益于而只会有害于统一战线的发展的,甚至会使统一战线受到严重破坏.

新买仔猪为何容易患病

近几年来,生猪疫病越来越复杂,新买仔猪发病率和死亡率很高。我们对5382头新买仔猪调查,有4148头患病,占新买仔猪的77%,死亡842头,占发病猪的20%多。有的农户连买几次都因发病而死亡。新买仔猪为何容易患病呢?一是仔猪突然断奶,母源抗体消失,自身抗病力差,各种疫病趁机侵入猪体。二是仔猪断奶前或上市后没有打防疫针,与病猪接触极易染病。三是新买仔猪发生环境、饲料,和喂法三大突变。

Clinical significance of K-ras and BRAF mutations in Chinese colorectal cancer patients

AIM:To identify and assess mutations in the K-ras and BRAF genes in a cohort of Chinese patients with colorectal cancer (CRC) for their association with various clinicopathological parameters and prognosis.METHODS:Genomic DNA was isolated from frozen tissues.Pyrosequencing analysis was conducted to detect mutations in the K-ras (codons 12,13,and 61) and BRAF genes (codon 600).Statistical analysis was carried out using SPSS-15.0 software.RESULTS:Among the 118 colorectal cancer patients,we detected 41 (34.7%) mutations in the K-ras gene.Mutation frequencies at codon 12 and codon 13 were 23.7% (28/118) and 10.2% (12/118),respectively.Only one patient harbored a point mutation at codon 61 (0.8%,1/118).Gender was the only factor that showed an obvious relationship with K-ras gene mutation (female 44.7% vs male 28.2%,P=0.037).Other clinicopathological features,such as age,location of the tumor,tumor differentiation,Tumor,Node and Metastases classification,and the Union for International Cancer Control staging,showed no positive relationship with K-ras gene mutations.No significant correlation was observed between the presence of K-ras mutations (codons 12,13,and 61) and the survival of the patients.BRAF mutations were rare,and only two patients (1.7%) harbored a detectable mutation at codon 600.CONCLUSION:K-ras gene mutation is a common event in our 118 Chinese CRC patients,with an obvious relationship with gender.However,it seems not to be an independent prognostic factor in CRC patients.The BRAF gene is rarely mutated in Chinese CRC patients.

Applications of gene-chip for the detection of mutations in cTnI gene associated with FHCM

Mutations in cardiac troponin I （cTnI） gene were assessed based on gene-chip technology.Special probes were designed to fabricate the low-density gene-chip,which could detect the mutations in exons 3,5,7,and 8 of the cTnI gene simultaneously.For each exon,two oligonucleotide sequences labeled with fluorescein at the 5＇-end were designed,one （oligonucleotide Ⅰ） simulating the wild type and the other （oligonucleotide Ⅱ） simulating the mutant.Oligonucleotides Ⅰ and Ⅱ were mixed together to simulate the heterozygote.After optimizing the hybridization protocols,the fabricated gene-chip could detect the mutations in the exons of the cTnI gene with relative high sensitivity and specificity.The fully complementary probe gave a fluorescent signal almost 50% stronger than that of the one-base mismatched one,which is in accordance with the result from a theoretical estimate. An applicable special gene-chip is available to investigate and diagnose familial hypertrophic cardiomyopathy （FHCM） after further improvement.

PI3K expression and PIK3CA mutations are related to colorectal cancer metastases

AIM: To assess the significance of phosphatidylinositol 3-kinase (PI3K) in colorectal cancer (CRC) and toxicity of LY294002 in CRC cells with different metastatic abilities. METHODS: Sixty formalin-fixed and paraffin-embedded CRC tumor specimens were investigated. Adjacent normal colonic mucosa specimens from 10 of these cases were selected as controls. PI3K protein was detected by immunohistochemistry and PIK3CA mutations were investigated by gene sequencing analysis. A flowcytometry-based apoptosis detection kit was used to determine PI3K inhibitor-induced apoptosis in CRC cell lines SW480 and SW620. Expression of phosphorylated protein kinase B in CRC cell lines was detected by Western blotting. RESULTS: There was a significant difference in the proportion of primary lesions (30%, 18/60) vs metastatic lesions (46.7%, 28/60) that were positive for PI3K (P < 0.05). Mutations were detected in exon 9 (13.3%) and exon 20 (8.3%). Out of 60 cases, seven mutations were identified: two hotspot mutations, C.1633G>A resulting in E545A, and C.3140A>G resulting in H1047R; two novel missense mutations C.1624G>A and C.3079G>A; and three synonymous mutations (C.1641G>A, C.1581C>T and C.3027T>A). Exposure of SW480 cells to PI3K inhibitor for 48 h resulted in a significant increase of apoptotic cells in a dose-dependent manner [3.2% apoptotic cells in 0 μmol/L, 4.3% in 5 μmol/L, 6.3% in 10 μmol/L (P < 0.05), and 6.7% in 20 μmol/L (P < 0.05)]. Moreover, PI3K inhibitor induced a similar significant increase of apoptotic cells in the SW620 cell line for 48 h [3.3% apoptotic cells in 0 μmol/L, 13.3% in 5 μmol/L (P < 0.01), 19.2% in 10 μmol/L (P < 0.01), and 21.3% in 20 μmol/L (P < 0.01)]. CONCLUSION: High PI3K expression is associated with CRC metastasis. PI3K inhibitor induced apoptosis in CRC cells and displayed strong cytotoxicity for highly metastatic cells. PI3K inhibition may be an effective treatment for CRC.

Identification and characterization of the Vibrio anguillarum prtV gene encoding a new metalloprotease

We cloned and sequenced a prtV-like gene from Vibrio anguillarum M3 strain.This prtV gene encodes a putative protein of 918 amino acids,and is highly homologous to the V.cholerae prtV gene.We found that a prtV insertion mutant strain displayed lower gelatinase activity on gelatin agar,lower protease activity against azocasein,and lower activity for four glycosidases.This prtV mutant strain also had increased activity for two esterases in its extracellular products,as analyzed by the API ZYM system.In addition,the prtV mutant strain exhibited decreased growth in turbot intestinal mucus and reduced hemolytic activity on turbot erythrocytes.Infection experiments showed that the LD50 of the prtV mutant strain increased by at least 1 log compared to the wild-type in turbot fish.We propose that prtV plays an important role in the pathogenesis of V.anguillarum.

Influence of human mutant p27 gene on the biological behaviors of colon cancer cells

Objective： To observe the influence of human mutant p27 gene （p27mt） on the growth and apoptosis of colon cancer cells so as to investigate the function mechanism of p27mt in gene therapy for colon cancer. Methods： Colon cancer cell line SW480 was infected with recombinant replication defective adenovirus Ad-p27mt, and expression of p27mt protein was detected by Western blot; the inhibition effect of p27mt on SW480 cells was detected with cytometry. Cell cycle was decided with flow cytometer, and DNA fragment analytic process identified the occurrence of apoptosis. Results： After transfected SW480 cells with Ad-p27mt, high expression of p27 protein was identified with immunoblotting assay. PI staining and flow cytometer assay showed 77.96% colon cancer cells was blocked in phase G0/G1, while in Ad-LacZ group and blank control group, 27.57% and 25.29% cells were blocked in the same phase, respectively. Growth curve showed Ad-p27mt has an obvious inhibition effect on the growth of SW480 cells, DNA fragment assay demonstrated that p27mt was able to induce the apoptosis of colon cancer cells. Conclusion： p27mt has an obvious blocking effect on colon cancer cell cycle, and most cells were blocked in phase G0/G1. This blockage is related with the growth inhibition and apoptosis induction effect of p27mt.

Interrelationship between microsatellite instability and microRNA in gastrointestinal cancer

There is an increasing understanding of the roles that microsatellite instability （MSI） plays in Lynch syndrome （by mutations） and sporadic （by mainly epigenetic changes） gastrointestinal （GI） and other cancers. Defi- cient DNA mismatch repair （MMR） results in the strong mutator phenotype known as MSI, which is the hall- mark of cancers arising within Lynch syndrome. MSI is characterized by length alterations within simple repeated sequences called microsatellites. Lynch syn- drome occurs primarily because of germline mutations in one of the MMR genes, mainly MLH1 or MSH2, less frequently MSH6, and rarely PMS2. MSI is also observed in about 15% of sporadic colorectal, gastric, and en-dometrial cancers and in lower frequencies in a minor- ity of other cancers where it is often associated with the hypermethylation of the IVlLH1 gene. miRNAs are small noncoding RNAs that regulate gene expression at the posttranscriptional level and are critical in many biological processes and cellular pathways. There is accumulating evidence to support the notion that the interrelationship between MSI and miRNA plays a key role in the pathogenesis of GI cancer. As a possible new mechanism underlying MSI, overexpression of m/R-IEE has been shown to downregulate expression of MLH1, IVlSH2, and MSH6. Thus, a subset of MSI-positive （MSI＋） cancers without known MMR defects may result from m/R-1E5 overexpression. Target genes of frameshift mutation for MSI are involved in various cellular func- tions, such as DNA repair, cell signaling, and apoptosis. A novel class of target genes that included not only epi- genetic modifier genes, such as HDAC2, but also miRNA processing machinery genes, including TARBP2 and XPO5, were found to be mutated in MSI＋ GI cancers. Thus, a subset of MSI＋ colorectal cancers （CRCs） has been proposed to exhibit a mutated miRNA machinery phenotype. Genetic, epigenetic, and transcriptomic dif- ferences exist between MSI＋ and MSI- cancers. Mo- lecular signatures of miRNA expression apparently have the potential to distinguish between MSI＋ and MSI- CRCs. In this review, we summarize recent advances in the MSI pathogenesis of GI cancer, with the focus on its relationship with miRNA as well as on the potential to use MSI and related alterations as biomarkers and novel therapeutic targets.

Germination Tolerance of Four Mutant Lines of Barley （Hordium vulgare L.）, Wheat （Triticum aestivum L.） and Garden Cress （Lipidium sativum L.） to Crude Oil Contaminated Soil

Phytoremediation shows promise as an alternative low-cost to most remediation methods. This study evaluated the germination of six crops, including four mutant lines of barley （Hordium vulgate L.） （1-9-3, 150-2-3, 1-1-200 and 150-1-5）, wheat （Triticum aestivum L.） and garden cress （Lipidium sativum L.）. This experiment was conducted in laboratory at room temperature. Oil extracted from crude oil contaminated soil was added to sand used in different concentrations （0%, 2%, 4%, 6%, 8% and 10%）. 10 seeds of each crop were sown in ptri-dishes with different treatments separately. For Each treatment four replicates were used in completely randomized design, germination percent was calculated, after one week, shoot and root length were measured. Data were statistically analyzed using MINTAB version 12. The results show that barley mutant line （150-2-3） was significantly different from other entries in germination percent, shoot and root length except mutant line 150-1-5 in germination percent. Results demonstrated that the mutant line 150-2-3 was promising to remediate crude oil contaminated soil.

A THEORETICAL STUDY ON THE MULTIPLE EQUILIBRIA OF TROPICAL ATMOSPHERE AND THEIR RELATION TO THE ONSET OF THE SUMMER MONSOON

Multiple equilibria and their stability in tropical atmosphere are investigated through β-plane barotropic models with consideration of heating and dissipation. We have derived the solutions of the model equations corresponding to the multiple equilibria or the steady flows first, and then establish the criteria for the stability of steady flow by use of the Liapunov direct Method. When these criteria are applied to the solutions of equilibria obtained, stable flows, which are closely related to the different patterns of quasi-stationary circulation in the tropical region, are lbund. The configurations of these stable flows and the shift between two of them as season changes provide quite reasonable explanations to many fundarnental problems of tropical circulation features such as the catastrophe mechanism of the onset and the break-active cycle of the Asian summer monsoon. It fbllows that the onset or the abrupt transition of the Asian summer monsoon could be attributed to the multiple equilibrium property of the tropical circulation resulted from the advcetive nonlinearity, which provide another explanation among others.

Weakening of the biennial relationship between Central American and equatorial South American rainfall in recent decades

There is a rainfall variability biennial relationship between Central America （CA） and equatorial South America （ESA） over the tropical western hemisphere, which is known to have arisen due to the combined effects of ENSO and tropical North Atlantic （TNA） SST. Here, the authors report that this biennial rainfall relationship between CA and ESA has weakened remarkably since 2000, with weakening in both in-phase and out-of-phase rainfall transitions. The observed decadal changes in the biennial relationship between CA and ESA rainfall can be attributed to changes in the effects of ENSO and TNA SST since 2000, which may be associated with more frequent occurrences of the central Pacific or＇Modoki＇ type El Ni^o. The weakening of the association with ENSO for CA rainfall since 2000 might have given rise to the weakening of the in-phase rain transition from CA rainfall to the following ESA rainfall. The weakened linkage between boreal-winter ESA rainfall and the subsequent boreal-summer TNA SST since 2000 may have resulted in the weakening of the out- of-phase rainfall transition from boreal-winter ESA rainfall to the subsequent boreal-summer CA rainfall.

Weakened interannual variability of the contrast in rainfall between the eastern equatorial Pacific and equatorial Atlantic since 2000

Recent studies suggest that the interannual variability in the tropical Pacific associated with the El Nino-Southern Oscillation has weakened since 2000. In this study, the authors report that the interannual variability of the contrast in rainfall between the eastern equatorial Pacific and equatorial Atlantic has also weakened remarkably since 2000, attributable to the weakened interannual variability in the zonal sea surface temperature gradient between the eastern equatorial Pacific and equatorial Atlantic and in the associated equatorial low-level zonal wind across South America linking the two ocean basins. Diagnosis of a column-integrated moisture budget indicates that the weakening in the interannual variability of the contrast in rainfall is primarily attributable to the changes in moisture convergence associated with vertical motion. The results highlight the clear weakened interannual variability in the coupled equatorial Pacific-Atlantic climate system since 2000, including the Pacific El Nino, Atlantic Nino, equatorial zonal wind across South America, and rainfall over the eastern equatorial Pacific and equatorial Atlantic.

Abrupt Climate Changes of Holocene

This paper is a review of studies of abrupt climate changes(ACCs) during the Holocene published during the past ten years.North Atlantic cold events are indicators of ACCs.As indicated by North Atlantic ice-rafted debris(IRD),there were nine confirmed cold events during the Holocene,occurring at 11.1 kyr,10.3 kyr,9.4 kyr,8.1 kyr,5.9 kyr,4.2 kyr,2.8 kyr,1.4 kyr,and 0.4 kyr respectively according to most representative results from Bond et al.(1997).However,the identification of chronology has been made with some uncertainties.Considerable climatic proxy data have shown that,during the cold events,substantial climate abnormalities have occurred widely across the globe,particularly in the areas surrounding the North Atlantic.These abnormalities were in the form of high-latitude cold in the both hemispheres,expansion of the Westerlies to low latitudes,drought in the monsoon regions,recession of summer monsoons,and intensification of the winter monsoons.Studies have indicated that the four ACCs occurring in the early Holocene may be related to freshwater pulses from ice melting in the northern part of the North Atlantic,and the other five ACCs that occurred during the middle and late Holocene may be related to the decreased solar activity.

The Use of Str Mutations for Enhancement of Hydrogen Peroxide Formation by Lactobacillus Delbrueckii MH-IO at Refrigeration

The strains ofLactobacillus delbrueckii subsp, lactis widely used in food preservation due to ability produce high amount of hydrogen peroxide at refrigerator temperatures to inhibit food-borne pathogens and psychrophilic spoilage microorganisms. In order to improve of bio-preservation efficacy ofL. delbrueckii MH 10 mutations causing resistance to streptomycin （str） were used. Among UV-mutagenized population of L. delbruecla＇i three str mutants producing high amounts of H2O2 were selected. Sir mutants produced significant amounts of hydrogen peroxide 50-60 μg/ml in sodium phosphate buffer （0.2 M, pH 6.5） and in beef broth （BB） at 5 ℃ for 5 days submerged cultivation without of growth. Evaluation mutants antibacterialactivity at refrigeration temperatures against food-borne pathogen Escherichia coli O157：H7 revealed elimination of pathogen total number up to practically undetectable amount for 3 days. In case of solid-state cultivation on agar-based medium, disks soaked by mutant cells suspensions formed larger inhibitory zones on E. coli O157：H7 lawn for one-day cold exposition. The size of inhibition zone depends on concentration of LAB cells. Str mutants L. delbrueckii reduced initial amount 2 - 105 of E. coil O 157：H7 in ground beef up to 3 log for 3 days of solid-state cocultivation when the wild strain reduced only 2 log. The application ofL. delbrueckii mutants did not cause any changes in sensory characteristics of ground beef, moreover promotes expanding of shelf-life due to inhibition of psychrophilic spoilage microorganisms.

Differential roles of EPS8 in carcinogenesis:Loss of protein expression in a subset of colorectal carcinoma and adenoma

AIM:To analyze the epidermal growth factor receptor pathway substrate 8(EPS8) expression status and role in colorectal carcinogenesis given that EPS8 has a conserved actin barbed-end capping function that is required for proper maturation in intestinal cells.METHODS:We studied 8 colon cancer cell lines and 58 colorectal tumors(19 adenomas and 39 carcinomas).We performed expression microarray analysis of colon cancer cell lines followed by loss of heterozygosity(LOH)analysis and immunohistochemistry for EPS8 expression in colon tumors.Subsequently,we performed mutation analysis by direct sequencing and methylation analysis by bisulfite sequencing and methylation-specific polymerase chain reaction assays.RESULTS:Expression microarray analysis of colon cancer cell lines showed overexpression of EPS8 transcript in all lines but RKO.Genome wide loss of heterozygosity(LOH) analysis of colon tumors,showed considerable LOH at the EPS8 gene locus.Immunohistochemically,EPS8 was constitutively expressed in normal colonic mucosa with a dot-like supranuclear localization with accentuation at the luminal surface supporting its proposed role in epithelial maturation.Nineteen colon tumors(4 adenoma,15 carcinoma) out of 51(37%) showed strikingly tumor specific EPS8 protein loss.Of the remaining tumors,5/51(2 adenoma,and 3 carcinoma,10%) showed marked overexpression,while 27/51 tumors(53%) showed retained expression.Mutation analysis revealed a missense mutation(c.794C>T,p.R265C) in exon 8 in RKO.The EPS8 promoter was also methylated in RKO,but there was no significant methylation in other cell lines or carcinoma specimens.CONCLUSION:The loss of EPS8 expression in colorectal adenomas and carcinomas suggests that down regulation of this gene contributes to the development of a subset of colorectal cancers,a finding which could have applications in diagnosis and treatment.

生物进化是渐变,还是突变?

生物界如同变化无穷的舞台。任何生物种群都是由先前的祖型物种变化而来的。由于变异,生物不断地分化,由少到多,开创出前所未有的新种群。如,无脊椎动物进化到鱼类之后,鱼类逐渐分化,种类越来越多。据一些鱼类学家估计,鱼类至今已鉴定的就达25,000多种。随着深海捕鱼技术的发展,新的鱼类又将被发现,鱼类数量可能要突破到30,000种的新纪录。整个生物界被证明是在永恒的进化着、发展着。然而,生物进化是渐变还是突变呢?这却是自从达尔文以来一直争论的问题。