Efficient expression of green fluorescent protein （GFP） mediated by a chimeric promoter in Chlamydomonas reinhardtii

To improve the expression efficiency of exogenous genes in Chlamydomonas reinhardtii, a high efficient expression vector was constructed. Green fluorescent protein （GFP） was expressed in C. reinhardtii under the control of promoters： RBCS2 and HSP70A-RBCS2. Efficiency of transformation and expression were compared between two transgenic algae： RBCS2 mediated strain Tran-Ⅰ and HSP70A-RBCS2 mediated strain Tran-Ⅱ. Results show that HSP70A-RBCS2 could improve greatly the transformation efficiency by approximately eightfold of RBCS2, and the expression efficiency of GFP in Tran-Ⅱ was at least double of that in Tran-Ⅰ. In addition, a threefold increase of GFP in Tran-Ⅱ was induced by heat shock at 40℃. All of the results demonstrated that HSP70A-RBCS2 was more efficient than RBCS2 in expressing exogenous gene in C. reinhardtii.     

Steroids from green alga <Emphasis Type="Italic">Chaetomorpha basiretorsa</Emphasis> Setchell

Six steroids have been isolated from ethanolic extract of green alga Chaetomorpha basiretorsa Setchell by a combination of repeated normal phase silica gel and Sephadex LH-20 gel column chromatography as well as recrystallization. Using spectroscopic methods including MS and NMR, their structures were determined as β-1awsaritol （1）, saringosterol （2）, 24-hydroperoxy-24-vinyl- cholesterol （3）, β-stigmasterol （4）, stigmast-4-en-3α, 6β-diol （5）, 29-hydroxystigmasta-5, 24 （28）-dien-3β-ol （6）. All these compounds were obtained from this genus for the first time and they were inactive （IC50〉10μg/ml） against KB, Bel-7402, PC-3M, Ketr 3 and MCF-7 cell lines.     

日照市土地利用功能分区及空间管制

不同地区自然及经济社会条件的差异,决定了对土地资源的开发利用必须注重其区域性,即进行土地利用功能分区,以协调不同区域的土地利用,限制不适当的土地利用方式,达到人地关系的真正和谐,实现土地资源的可持续利用。通过分析日照市土地资源开发利用现状,采用图件叠加的方法进行初步功能分区,然后采用系统聚类分析法进一步细分,同时对不同功能区制定相应空间管制措施。     

Distribution and retention of Petrolisthes armatus in a coastal plain estuary: The role of vertical movement in larval transport

Since transport of planktonic larvae is essential to the maintenance and expansion of many marine species, we examined the spatial and temporal distribution of green porcelain crab Petrolisthes armatus (Gibbes, 1850) larvae and the possible underlying physical and behavioral mechanisms using a combination of field observations and numerical modeling. The field study consisted of observations of larval abundance and distribution as well as hydrographic surveys of the Satilla River estuary on the east coast of the USA in August 2006. Larvae were found throughout the water column within the tributaries but primarily at depth in the main river. A numerical model was used to examine the effect of flow and possible larval behavior responsible for the observed distribution and the consequences for larval retention in the estuary. Model results that included downward larval movement are consistent with the field observations, supporting the hypothesis that P. armatus larvae vertically migrate within the water column, which aids in their retention within the estuary.     

海泡石对有机染料的吸附行为研究

以热酸活化过的海泡石为吸附剂，研究其对亚甲基蓝、结晶紫和甲基绿3种染料的吸附动力学过程，并分析了浓度、温度等因素对海泡石吸附效果的影响。结果表明，温度的变化对吸附的影响较小，而染料溶液浓度的改变则会对吸附产生很大的影响，由此确定出较适合的反应条件。采用傅立叶红外光谱技术对吸附前后海泡石的结构进行了分析，发现亚甲基蓝由于分子体积较小可以进入海泡石内部通道，而大体积的结晶紫和甲基绿的吸附主要发生在海泡石外表面，且一价有机阳离子会在中性位置发生吸附，形成带电或中性复合物。     

基于百度AI卷积神经网络的茶树结霜智能识别北大核心

基于采集的近20000张茶园图像,分别筛选出1000张茶园结霜和1000张未结霜图像作为训练样本,利用百度AI开放平台的EasyDL经典版图像识别功能,应用卷积神经网络算法,建立茶园结霜识别模型,进行茶树结霜图像智能判别。茶树结霜智能识别模型的准确率、F1评分、精确率、召回率分别为99.2%、99.2%、99.3%、99.1%。模型检验结果为:样本地20张结霜图像的平均识别置信度为95.51%,20张非结霜图像的平均识别置信度为99.99%;非样本地(江南茶区)80张结霜图像的平均识别置信度为97.53%,80张非结霜图像的平均识别置信度为95.11%。     

技术进步偏向视角下中国海洋经济绿色增长效率研究进展

近年来关于海洋经济增长效率的研究层出不穷,但是目前尚未有文献对其进行过系统的综述.本文从技术进步中性与海洋经济传统全要素生产率、技术进步中性与海洋经济绿色全要素生产率、技术进步偏向与传统全要素生产率、技术进步偏向与绿色全要素生产率四方面对海洋经济增长理论进行了文献梳理,分析总结了近年来学者们在海洋经济增长效率领域的主要...     

海绵城市建设的绿化屋顶技术及其水文与环境效应研究进展

绿化屋顶作为海绵城市建设的重要措施之一,能够有效改善城市内涝、热岛效应、建筑能耗、城市绿化等生态环境问题,是一种可持续的城市低影响开发实践,具有较大的开发潜力.通过系统回顾和综述国内外绿化屋顶最新研究成果和发展趋势,指出了不同气候条件和绿化屋顶类型雨水年滞留率约为50％～90％,并能将室内温度降低约3℃～4℃,为绿化屋...     

日照市耕地“非粮化”现状及对策研究

本文就日照市耕地“非粮化”现状，结合近年来日照市及各区县耕地“非粮化”变动趋势，分析导致耕地“非粮化”的主要成因，有针对性提出意见、建议。日照市粮食种植面积总体呈现下降趋势，日照市耕地“非粮化”程度山东省最高，两区耕地“非粮化”程度好于两县，各区县耕地“非粮化”程度均呈增强态势。根据日照市耕地“非粮化”现状，提出要全面摸清全市耕地“非粮化”存量，因地制宜、统筹规划。同时要加大资金投入，精准施策落实好种粮补贴政策,提高种粮收益。     

气候变化背景下宁波市茶叶早春霜冻灾害风险评估北大核心

基于自然灾害风险理论,利用1971—2020年宁波市127个气象站气象观测资料和茶叶生产相关资料,分析了宁波市茶叶早春霜冻空间分布规律,并通过层次分析(Analytic Hierarchy Process,AHP)和专家经验相结合的方法,构建了宁波市茶叶早春霜冻风险因子集,通过加权指数求和的方法建立了宁波市茶叶早春霜冻风险模型,对早春霜冻灾害风险进行了综合和分年代的评估。结果表明,宁波市茶叶早春霜冻出现的年平均天数分布总体呈现西低东高的特征,霜冻年平均天数的范围在0.23~21.43 d;宁波市茶叶早春霜冻高风险区主要集中在余姚南部的四明山区域、宁海西部和宁海东北部的茶山区域,低风险区主要分布于宁波东部沿海地区;20世纪70—90年代宁波市茶叶早春霜冻低风险和较低风险区域基本呈增长趋势,中风险和较高风险区域呈减少趋势,高风险区域80年代最多、90年代次之、70年代最少,21世纪00—10年代,宁波市茶叶早春霜冻低风险和中风险区域呈减少趋势,较低风险、较高风险和高风险区域呈增长趋势。