A sequential estimation technique for capture-recapture censuses

A simple technique of sequential estimation was proposed for capture-recapture census by thePetersen method. In theory this technique makes it possible to secure automatically a required precision level for the population estimate to be obtained, irrespective of the population size. Some problems about its practical application were discussed.     

A sequential estimation technique for capture-recapture censuses

Summary A simple technique of sequential estimation was proposed for capture-recapture census by thePetersen method. In theory this technique makes it possible to secure automatically a required precision level for the population estimate to be obtained, irrespective of the population size. Some problems about its practical application were discussed. This study was supported by science research fund from the Ministry of Education.     

1H and 15N resonance assignments and secondary structure of the carbon monoxide complex of sperm whale myoglobin

Summary Sequence-specific backbone ¹H and ¹⁵N resonance assignments have been made for 95% of the amino acids in sperm whale myoglobin, complexed with carbon monoxide (MbCO). Many assignments for side-chain resonances have also been obtained. Assignments were made by analysis of an extensive series of homonuclear 2D spectra, measured with unlabeled protein, and both 2D and 3D ¹H-¹⁵N-correlated spectra obtained from uniformly ¹⁵N-labeled myoglobin. Patterns of medium-range NOE connectivities indicate the presence of eight helices in positions that are very similar to those found in the crystal structures of sperm whale myoglobin. The resonance assignments of MbCO form the basis for determination of the solution structure and for hydrogen-exchange measurements to probe the stability and folding pathways of myoglobin. They will also form a basis for assignment of the spectra of single-site mutants with altered ligand-binding properties.     

Data and knowledge based experimental design for fermentation process optimization

A novel method for the sequential experimental design in order to optimize fed-batch fermentations was applied to a hyaluronidase fermentation by Streptococcus agalactiae. A Λ-optimal design was introduced to minimize the model parameter estimation error and to maximize the performance of the fermentation process. The method employs hybrid models that contain mechanistic, fuzzy and neural network components.     

四联疗法与序贯疗法根除幽门螺杆菌疗效观察

目的：探讨四联疗法和序贯疗法根除幽门螺杆菌的疗效和安全性。方法：将150例14C尿素呼气试验阳性的慢性胃炎患者随机分为A、B、C3组各50例。A组（四联疗法）给予雷贝拉唑、枸橼酸铋钾、克拉霉素、阿莫西林治疗7d;B组（序贯疗法）前5d给予雷贝拉唑、阿莫西林,后5d给予雷贝拉唑、克拉霉素、甲硝唑治疗;C组（标准三联疗法）给予雷贝拉唑、克拉霉素、阿莫西林治疗治疗7d。疗程结束4周后行14C尿素呼气试验检测。结果：A组根除率为94％,B组根除率为90％,c组根除率68％。A组和B组优于c组（P〈0．01）;A组、B组无显著差异性（P〉0．05）。三组均无严重不良反应。结论：四联疗法与序贯疗法H．pylori根除率优干标缝三联疗法．四联疗法和庠骨疗法疗效无．明昂差异性．     

Bio-hydrogen production from cellulose by sequential co-culture of cellulosic hydrogen bacteria of <Emphasis Type="Italic">Enterococcus gallinarum</Emphasis> G1 and <Emphasis Type="Italic">Ethanoigenens harbinense</Emphasis> B49

Microbial conversion of lignocellulose to hydrogen is a fascinating way to provide a renewable energy source. A mesophilic bacterium strain G1 that had high cellulose degradation and hydrogen production activity (2.38 mmol H₂ g⁻¹ cellulose) was isolated from rumen fluid and identified as the Enterococcus gallinarum. Hydrogen production from cellulose by using sequential co-cultures of a cellulosic-hydrolysis bacterium G1 and Ethanoigenens harbinense B49 was investigated. With an initial Avicel concentration of 5 g l^−l, the sequential co-culture with G1 and strain Ethanoigenens harbinense B49 produced H₂ yield approximately 2.97 mmol H₂ g⁻¹ cellulose for the co-culture system.     

Dynamic Comparison of Kaplan–Meier Proportions: Monitoring a Randomized Clinical Trial with a Long-Term Binary Endpoint

Summary .   The approach to early termination for efficacy in a trial where events occur over time but the primary question of interest relates to a long-term binary endpoint is not straightforward. This article considers comparison of treatment groups with Kaplan–Meier (KM) proportions evaluated at increasing times from randomization, at increasing calendar testing times. This strategy is employed to improve the ability to detect important treatment effects and provide critical treatments to patients in a timely manner. This dynamic Kaplan–Meier (DKM) approach is shown to be robust; that is, it produces high power and early termination time across a wide range of circumstances. In contrast, a fixed time KM comparison and the log-rank test are both shown to be more variable in performance. Practical considerations of implementing the DKM method are discussed.     

四联疗法与序贯疗法根除幽门螺杆菌疗效观察

目的:探讨四联疗法和序贯疗法根除幽门螺杆菌的疗效和安全性。方法:将150例14C尿素呼气试验阳性的慢性胃炎患者随机分为A、B、C 3组各50例。A组(四联疗法)给予雷贝拉唑、枸橼酸铋钾、克拉霉素、阿莫西林治疗7 d;B组(序贯疗法)前5d给予雷贝拉唑、阿莫西林,后5d给予雷贝拉唑、克拉霉素、甲硝唑治疗;C组(标准三联疗法)给予雷贝拉唑、克拉霉素、阿莫西林治疗治疗7 d。疗程结束4周后行14C尿素呼气试验检测。结果:A组根除率为94%,B组根除率为90%,C组根除率68%。A组和B组优于C组(P<0.01);A组、B组无显著差异性(P>0.05)。三组均无严重不良反应。结论:四联疗法与序贯疗法H.pylori根除率优于标准三联疗法,四联疗法和序贯疗法疗效无明显差异性。     

序贯肠内营养对老年重症脑卒中患者营养代谢、免疫功能及预后的影响

目的:探讨序贯肠内营养对老年重症脑卒中患者营养代谢、免疫功能和预后的影响。方法:将90例老年重症脑卒中患者随机分为序贯肠内营养组30例、肠内营养组30例和对照组30例予以营养支持。入院第1天和第14天分别检测患者营养指标、免疫功能指标、格拉斯哥昏迷评分(GCS)、美国国立卫生院神经功能缺损评分(NIHSS);统计3组患者住院期间并发症发生率。结果:治疗14天后3组各项指标均较第1天明显下降,对照组较序贯肠内营养组和肠内营养组下降更明显;与对照组相比较,治疗14天后序贯肠内营养组和肠内营养组TLC、IgA,IgM,IgG水平明显升高;GCS评分明显升高,NIHSS评分明显降低;序贯肠内营养组、肠内营养组各项并发症较对照组发生率低。结论:老年重症脑卒中患者随病程延长,营养状况呈恶化趋势。肠内营养可改善患者营养状况,改善机体免疫功能,降低并发症发生率,改善预后。序贯肠内营养较肠内营养效果更佳。     

Mate choice and uncertainty in the decision process

The behavior of females in search of a mate determines the likelihood that a high quality male is encountered in the search process and alternative search strategies provide different fitness returns to searchers. Models of search behavior are typically formulated on an assumption that the quality of prospective mates is revealed to searchers without error, either directly or by inspection of a perfectly informative phenotypic character. But recent theoretical developments suggest that the relative performance of a search strategy may be sensitive to any uncertainty associated with the to-be-realized fitness benefit of mate choice decisions. Indeed, uncertainty in the decision process is inevitable whenever unobserved male attributes influence the fitness of searchers. In this paper, we derive solutions to the sequential search strategy and the fixed sample search strategy for the general situation in which observed and unobserved male attributes affect the fitness consequences of female mate choice decisions and we determine how the magnitude of various parameters that are influential in the standard models alter these more general solutions. The distribution of unobserved attributes amongst prospective mates determines the uncertainty of mate choice decisions-the reliability of an observed male character as a predictor of male quality-and the realized functional relationship between an observed male character and the fitness return to searchers. The uncertainty of mate choice decisions induced by unobserved male attributes has no influence on the generalized model solutions. Thus, the results of earlier studies of these search models that rely on the use of a perfectly informative male character apply even if an observed male trait does not reveal the quality of prospective mates with certainty. But the solutions are sensitive to any changes of the distribution of unobserved male attributes that alter the realized functional relationship between an observed character and the fitness return to searchers. For example, the standard sequential search model exhibits a reservation property--the acceptability of prospective mates is delimited by a unique threshold criterion--and the existence of this model property under generalized conditions depends critically on the association between the observed and unobserved male characters. In our formulations of the models we assumed that females use a single male character to evaluate the quality of prospective mates, but the model properties generalize to situations in which male quality is evaluated by a direct inspection of multiple male characters.     

1H, 13C and 15N NMR backbone assignments and secondary structure of the 269-residue protease subtilisin 309 from Bacillus lentus

Summary ¹H, ¹³C and ¹⁵N NMR assignments of the backbone atoms of subtilisin 309, secreted by Bacillus lentus, have been made using heteronuclear 3D NMR techniques. With 269 amino acids, this protein is one of the largest proteins to be sequentially assigned by NMR methods to date. Because of the size of the protein, some useful 3D correlation experiments were too insensitive to be used in the procedure. The HNCO, HN(CO)CA, HNCA and HCACO experiments are robust enough to provide most of the expected correlations for a protein of this size. It was necessary to use several experiments to unambiguously determine a majority of the -protons. Combined use of HCACO, HN(COCA)HA, HN(CA)HA, ¹⁵N TOCSY-HMQC and ¹⁵N NOESY-HMQC experiments provided the H chemical shifts. Correlations for glycine protons were absent from most of the spectra. A combination of automated and interactive steps was used in the process, similar to that outlined by Ikura et al. [(1990) J. Am. Chem. Soc., 112, 9020–9022] in the seminal paper on heteronuclear backbone assignment. A major impediment to the linking process was the amount of overlap in the C and H frequencies. Ambiguities resulting from this redundancy were solved primarily by assignment of amino acid type, using C chemical shifts and TOCSY ladders. Ninety-four percent of the backbone resonances are reported for this subtilisin. The secondary structure was analyzed using 3D ¹⁵N NOESY-HMQC data and C secondary chemical shifts. Comparison with the X-ray structure [Betzel et al. (1992) J. Mol. Biol., 223, 427–445] shows no major differences.Supplementary material available from F.J.M. van de Ven: the source code (PASCAL) for the computer program described in this paper.     

蓝细菌光敏色素Alr1966GAF2及其突变体的表达与光化学性质研究

采用PCR技术从鱼腥藻（Anabaena sp.PCC7120）中扩增蓝细菌光敏色素基因片段alr1966gaf2,将alr1966gaf2插入到pET-30a（+）载体中,构建表达质粒pET-alr1966gaf2。最后将Alr1966GAF2与HO1、PcyA在E.coli BL21（DE3）中共表达获得色素蛋白Alr1966GAF2,并对该蛋白的光化学性质进行分析。结果显示,色素蛋白Alr1966GAF2结合色素为藻蓝胆素（phycoerythrobilin,PCB）或藻紫胆素（phycoviolobilin,PVB）,在3种不同吸收态15Z-P_{428 nm}、中间态和15E-P_{514 nm}之间具有顺序可逆光效应。通过定点突变技术将DXCF基序中的保守性Cys突变为Ala,获得了突变体Alr1966GAF2（C72A）。将Alr1966GAF2（C72A）与HO1、PcyA共表达,获得色素蛋白Alr1966GAF2（C72A）。研究结果表明Alr1966GAF2（C72A）结合色素为PCB,Alr1966GAF2（C72A）-PCB具有较强的荧光活性,其荧光量子的产率高达0.11。Alr1966GAF2（C72A）不仅能够共价结合PCB,还可以结合胆绿素（Biliverdin,BV）,均具有较强的红色荧光活性。