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951.
从前期构建的短蛸(Octopus ocellatus)c DNA文库中克隆获得了一个短蛸酪氨酸蛋白激酶(Oo Btk)基因的c DNA全长,其c DNA全长1191 bp,包括5’非编码区(UTR)259 bp,3’UTR 227 bp,开放阅读框(ORF)705 bp,编码234个氨基酸,预测理论等电点为8.50,分子量为27.7 k Da。运用实时荧光定量PCR法分析了在健康短蛸的不同组织以及鳗弧菌和藤黄微球菌刺激后血细胞中Oo Btk的表达规律,结果表明:Oo Btk在肌肉、外套膜、鳃、鳃心、系统心脏、肝胰脏、肾囊、胃、性腺和血细胞等各检测组织中均有表达,其中在肝胰脏的表达量最高;短蛸经鳗弧菌和藤黄微球菌刺激后,Oo Btk在血细胞中的表达量呈现出了明显的被诱导表达趋势,在鳗弧菌和藤黄微球菌刺激后6 h表达即增强,并分别在鳗弧菌刺激后48 h和藤黄微球菌刺激后12 h达到最高。Oo Btk参与短蛸对于鳗弧菌和藤黄微球菌刺激的应答过程。 相似文献
952.
基坑开挖数值分析中土体硬化模型参数的试验研究 总被引:8,自引:0,他引:8
土体硬化模型已成为基坑数值分析中最常用的本构模型之一,其应用的关键是计算参数的确定。首先采用薄壁取土器现场取得土样,通过基于GDS的三轴固结排水剪切试验、三轴固结排水卸载-再加载试验及标准固结试验获得了上海典型土层土体的三轴试验应力-应变曲线和固结试验荷载-应变关系曲线。然后根据曲线确定了各土层的HS模型参数,建立了各土层HS模型参数中切线模量 、割线模量 、加载模量 的比例关系,并探讨了这些模量与压缩模量 之间的比例关系。最后将各层的模型参数与模量间的比例关系与国内外其他软土地区的结果进行了比较。试验结果可作为上海地区及其他软土地区基坑工程数值分析中确定HS模型参数时的参考。 相似文献
953.
Alessandro Amorosi Luigi Bruno Bruno Campo Bianca Costagli Wan Hong Vincenzo Picotti Stefano Claudio Vaiani 《Sedimentology》2021,68(1):402-424
Despite increased application of subsurface datasets below the limits of seismic resolution, reconstructing near‐surface deformation of shallow key stratigraphic markers beneath modern alluvial and coastal plains through sediment core analysis has received little attention. Highly resolved stratigraphy of Upper Pleistocene to Holocene (Marine Isotope Stage 5e to Marine Isotope Stage 1) alluvial, deltaic and coastal depositional systems across the southern Po Plain, down to 150 m depth, provides an unambiguous documentation on the deformation of previously flat‐lying strata that goes back in time beyond the limits of morphological, historical and palaeoseismic records. Five prominent key horizons, accurately selected on the basis of their sedimentological characteristics and typified for their fossil content, were used as highly effective stratigraphic markers (M1 to M5) that can be tracked for tens of kilometres across the basin. A facies‐controlled approach tied to a robust chronology (102 radiocarbon dates) reveals considerable deformation of laterally extensive nearshore (M1), continental (M2 and M3) and lagoon (M4 and M5) marker beds originally deposited in a horizontal position (M1, M4 and M5). The areas where antiformal geometries are best observed are remarkably coincident with the axes of buried ramp anticlines, across which new seismic images reveal substantially warped stratal geometries of Lower Pleistocene strata. The striking spatial coincidence of fold crests with the epicentres of historic and instrumental seismicity suggests that deformation of marker beds M1 to M5 might reflect, in part at least, syntectonically generated relief and, thus, active tectonism. Precise identification and lateral tracing of chronologically constrained stratigraphic markers in the 14C time window through combined sedimentological and palaeoecological data may delineate late Quaternary subsurface stratigraphic architecture at an unprecedented level of detail, outlining cryptic stratal geometries at the sub‐seismic scale. This approach is highly reproducible in tectonically active Quaternary depositional systems and can help to assess patterns of active deformation in the subsurface of modern alluvial and coastal plains worldwide. 相似文献
954.
青海尕林格铁矿区地表有近200 m厚的第四系覆盖层,地质工作几乎无法开展,加之钻井控制有限,增加了该区勘探的难度。笔者在前人工作的基础上,运用小波多尺度方法分析了该区的平面磁异常,发现小波一阶、二阶细节突出了3线附近的断裂特征,同时对3线设计剖面作正演计算,也表明该剖面处在断裂位置。该推断已经被钻探验证。另外小波四阶细节(场源似深度456 m)表现为区域场特征,推断该区深度456 m以下存在磁铁矿体的可能不大,对位于异常中心的5号地质剖面的正演计算没有发现剩余异常,也映证了该区深部没有隐伏铁矿体。小波多尺度分析与2.5维人机交互反演技术等综合方法技术的应用,加深了对该区磁异常特征的认识,可以为钻孔布置提供有力的佐证。 相似文献
955.
利用量纲分析法研究太阳风磁层的能量耦合问题。得到了在考虑磁层对太阳风的粘滞作用情况下,行星际磁场北向时的太阳风-磁层能量耦合函数,并首次在耦合函数中引入太阳风温度变量,在此基础上得到了一般情况下的太阳风-磁层耦合函数. 相似文献
956.
J. Bech M. Suarez F. Reverter P. Tume P. Sánchez N. Roca A. Lansac 《Journal of Geochemical Exploration》2010
Data of trace element composition of phosphorites are scarce and incomplete. Phosphorites of different origins can vary substantially in trace element contents. In this paper 20 trace element concentrations of 35 sample phosphorites are reported. The geographical provenance is: Bayovar-Sechura (Peru), Khouribga, Youssoufia and Boucraa (Morocco), Gafsa (Tunisia), Florida (USA), Idaho and Phosphoria Formation (USA), North Carolina (USA), Algeria, Israel, Senegal, Syria and Togo. Aqua regia extracts were used to estimate the “pseudototal” values, following standard procedures (ISO 11466, 2002) and measured by ICP-AES and ICP-MS. 相似文献
957.
植被是全球及区域生态系统环境变化的重要指标,也是对人类社会活动有重要贡献的资源之一。为了研究关中平原城市群不同区域植被覆盖变化对自然和人文因子的响应,以划分为三个区域的植被作为研究对象,选取2000—2017年MODIS-NDVI遥感数据,运用趋势分析、探索性空间数据分析与地理探测器等方法,从时序演进与空间分布方面研究了18 a内植被覆盖的演化及分布特征,定量分析影响植被覆盖的主导因子。遥感数据要通过投影转换、拼接、最大值合成等方法进行处理,再运用Python程序进行影像批量裁剪,将遥感数据和气象数据进行分区统计,最后对该处理数据进行讨论研究。结论表明:(1)研究期内关中平原城市群植被覆盖呈显著上升趋势,NDVI平均值增速为0.077·(10 a)-1,阶段性变化特征明显,其中2005—2007阶段和2011—2013阶段极显著增加,最大上升速率达到了0.05·a-1。(2)空间上总体呈现"南高北低"的分布特征,研究区总体得到改善;高值区主要分布在南部秦岭北坡,受气候因子的影响更大,植被覆盖增加速度缓慢,达到轻度改善水平;低值区聚集在黄土高原边缘地区,植被增加趋势明显;中部关中平原极少... 相似文献
958.
Esophageal cancer exhibits one of the highest incidence and mortality rates in China. Malignant tumors caused by esophageal cancer, and the relationship to environmental factors has been the focus of many public health studies. This study applied spatial analysis to ascertain the relationship between water pollution and esophageal cancer mortality rates nationwide. We employed two datasets, including a national investigation of esophageal cancer rates and distribution, and national water quality grades in China's primary rivers and lakes. Esophageal cancer data were grouped based on different water quality grades, which included a scaled buffer distance from rivers and lakes. Non-parametric correlation analyses were performed to examine the presence or absence of the following correlations: (i) esophageal cancer mortality and buffer distance from rivers and lakes; and (ii) esophageal cancer mortality and water quality grade values. The present study revealed a significant positive correlation between widespread water pollution and esophageal cancer mortality nationwide; and a significant negative correlation between esophageal cancer mortality, and buffer distance from rivers and lakes. 相似文献
959.
Investigating the effect of soil models on deformations caused by braced excavations through an inverse-analysis technique 总被引:1,自引:0,他引:1
In this study, a series of inverse-analysis numerical experiments was performed to investigate the effect of soil models on the deformations caused by excavation by using the finite element method. The nonlinear optimization technique that was incorporated into the finite element code was used for the inverse-analysis numerical experiments. Three soil models (the hyperbolic model, pseudo-plasticity model, and modified pseudo-plasticity model) were employed in the intended numerical experiments on a well-documented excavation case history. The results indicate that wall deflection due to excavation can be accurately back-figured by each of the three soil models, while the ground surface settlement can be reasonably optimized only by the pseudo-plasticity model and the modified pseudo-plasticity model. Importantly, the modified pseudo-plasticity model can yield more reasonable simulations when the wall deflection and the ground surface settlement are simultaneously back-figured. The results show that selection of an adequate soil model that is capable of adequately describing the stress–strain-strength characteristics of the soils is essentially crucial when predicting the excavation-induced ground response. 相似文献
960.
结合吉青岭隧道的工程实际,分析了浅埋偏压不良地质条件下隧道进口段的施工风险,提出了采取初期支护加强,短循环开挖,初期支护封闭等综合地质病害预防措施。 相似文献