Thirty-two actinomycetes strains were isolated from sediment samples from 12 different sites at Lagos Lagoon and identified using standard physiological and biochemical procedures as well as 16S rDNA gene sequence ana...Thirty-two actinomycetes strains were isolated from sediment samples from 12 different sites at Lagos Lagoon and identified using standard physiological and biochemical procedures as well as 16S rDNA gene sequence analysis. Secondary metabolites were extracted from the strains and their anticancer activity on the K562 (Human acute myelocytic leukemia), HeLa (cervical carcinoma), AGS (Human gastric), MCF- 7 (breast adenocarcinoma) and HL-60 (Human acute promyelocytic leukemia) cell lines was determined. The metabolic extracts exhibited cytotoxicity with IC50 values ranging from 0.030 mg/mL to 4.4 mg/mL. The Streptomyces bingchenggensis ULS14 extract was cytotoxic against all the cell lines tested. The bioactivity-guided extraction and purification of the metabolic extracts from this strain yielded two purified anticancer compounds: ULDF4 and ULDF5. The structures of the extracted compounds were determined using spectroscopic analyses, including electrospray ionization mass spectrophotometer and nuclear magnetic resonance (1 Dimensional and 2 Dimensional), and were shown to be structurally similar to staurosporine and kigamicin. The IC50 of ULDF4 and ULDF5 against the HeLa cell line was 0.034 mg/mL and 0.075 mg/mL, respectively. This study is the first to reveal the anticancer potential of actinomycetes from Lagos Lagoon, which could be exploited for therapeutic purposes.展开更多
基于海洋平台自身的空间范围,自升式井架已成为海洋钻井平台最常用的一种井架。此类井架主要是以液压绞车为动力源,通过底段的滑轮系统进行起升。通过对自升式井架特点的介绍,确立井架在最大钩载(4500 k N)的工况下,采用SAFI 6.5.1.2结...基于海洋平台自身的空间范围,自升式井架已成为海洋钻井平台最常用的一种井架。此类井架主要是以液压绞车为动力源,通过底段的滑轮系统进行起升。通过对自升式井架特点的介绍,确立井架在最大钩载(4500 k N)的工况下,采用SAFI 6.5.1.2结构计算软件对LF13-2井架结构进行建模、施加约束、定义载荷,进行计算分析,最终获得各个受力单元的ULS值,用于校核整个井架的强度。此外,对井架进行了静态应变-应力试验,得到相对应的抗压和抗弯比率来验证SAFI软件计算的结果。经分析校核,SAFI理论计算结果与试验结果一致,满足实际承载要求。展开更多
Spans occur when a pipeline is laid on a rough undulating seabed or when upheaval buckling occurs due to constrained thermal expansion. This not only results in static and dynamic loads on the flowline at span section...Spans occur when a pipeline is laid on a rough undulating seabed or when upheaval buckling occurs due to constrained thermal expansion. This not only results in static and dynamic loads on the flowline at span sections,but also generates vortex induced vibration (VIV),which can lead to fatigue issues. The phenomenon,if not predicted and controlled properly,will negatively affect pipeline integrity,leading to expensive remediation and intervention work. Span analysis can be complicated by:long span lengths,a large number of spans caused by a rough seabed,and multi-span interactions. In addition,the complexity can be more onerous and challenging when soil uncertainty,concrete degradation and unknown residual lay tension are considered in the analysis. This paper describes the latest developments and a'state-of-the-art' finite element analysis program that has been developed to simulate the span response of a flowline under complex boundary and loading conditions. Both VIV and direct wave loading are captured in the analysis and the results are sequentially used for the ultimate limit state (ULS) check and fatigue life calculation.展开更多
基金supported by the University of Lagos Central Research Committee Grant (Grant No: ULCRC 2012/08)
文摘Thirty-two actinomycetes strains were isolated from sediment samples from 12 different sites at Lagos Lagoon and identified using standard physiological and biochemical procedures as well as 16S rDNA gene sequence analysis. Secondary metabolites were extracted from the strains and their anticancer activity on the K562 (Human acute myelocytic leukemia), HeLa (cervical carcinoma), AGS (Human gastric), MCF- 7 (breast adenocarcinoma) and HL-60 (Human acute promyelocytic leukemia) cell lines was determined. The metabolic extracts exhibited cytotoxicity with IC50 values ranging from 0.030 mg/mL to 4.4 mg/mL. The Streptomyces bingchenggensis ULS14 extract was cytotoxic against all the cell lines tested. The bioactivity-guided extraction and purification of the metabolic extracts from this strain yielded two purified anticancer compounds: ULDF4 and ULDF5. The structures of the extracted compounds were determined using spectroscopic analyses, including electrospray ionization mass spectrophotometer and nuclear magnetic resonance (1 Dimensional and 2 Dimensional), and were shown to be structurally similar to staurosporine and kigamicin. The IC50 of ULDF4 and ULDF5 against the HeLa cell line was 0.034 mg/mL and 0.075 mg/mL, respectively. This study is the first to reveal the anticancer potential of actinomycetes from Lagos Lagoon, which could be exploited for therapeutic purposes.
文摘基于海洋平台自身的空间范围,自升式井架已成为海洋钻井平台最常用的一种井架。此类井架主要是以液压绞车为动力源,通过底段的滑轮系统进行起升。通过对自升式井架特点的介绍,确立井架在最大钩载(4500 k N)的工况下,采用SAFI 6.5.1.2结构计算软件对LF13-2井架结构进行建模、施加约束、定义载荷,进行计算分析,最终获得各个受力单元的ULS值,用于校核整个井架的强度。此外,对井架进行了静态应变-应力试验,得到相对应的抗压和抗弯比率来验证SAFI软件计算的结果。经分析校核,SAFI理论计算结果与试验结果一致,满足实际承载要求。
文摘Spans occur when a pipeline is laid on a rough undulating seabed or when upheaval buckling occurs due to constrained thermal expansion. This not only results in static and dynamic loads on the flowline at span sections,but also generates vortex induced vibration (VIV),which can lead to fatigue issues. The phenomenon,if not predicted and controlled properly,will negatively affect pipeline integrity,leading to expensive remediation and intervention work. Span analysis can be complicated by:long span lengths,a large number of spans caused by a rough seabed,and multi-span interactions. In addition,the complexity can be more onerous and challenging when soil uncertainty,concrete degradation and unknown residual lay tension are considered in the analysis. This paper describes the latest developments and a'state-of-the-art' finite element analysis program that has been developed to simulate the span response of a flowline under complex boundary and loading conditions. Both VIV and direct wave loading are captured in the analysis and the results are sequentially used for the ultimate limit state (ULS) check and fatigue life calculation.
