嗜虫耶尔森氏菌HlyA及HasA外分泌表达系统的构建

【目的】构建一株具备外分泌蛋白功能的工程菌,解决杀虫毒素无法由胞内分泌至胞外,无法直接作用于虫体等问题,为松墨天牛防治提供新思路。【方法】本研究先测定从松墨天牛肠道及其生境中分离出的嗜虫耶尔森氏菌(CSLH88)的生长特性及抗性,进而对其进行分子改造。构建HlyA (pGHKW2)以及HasA (pGHKW4)外分泌表达载体,利用电穿孔法将其转入CSLH88菌株,获得能够表达绿色荧光蛋白的工程菌。利用稀释涂板及荧光体式镜检测技术对两个质粒进行遗传稳定性检测,并采用SDS-PAGE及Western blotting技术验证蛋白外分泌功能。【结果】CSLH88菌株培养2–4 h能够进入对数生长期,并对卡那霉素(Kan)敏感。成功构建了含有Kan抗性基因的pGHKW2(GenBank:MK562405)和pGHKW4(GenBank:MK562404)两个外分泌表达载体的CSLH88工程菌株。其中,发现pGHKW4质粒更加适合在嗜虫耶尔森氏菌中稳定遗传。SDS-PAGE及Western blotting检测结果表明HlyA系统无法在CSLH88菌株中将目的蛋白分泌到胞外,而HasA系统则可以有效地发挥外分泌表达功能。【结论】通过对HlyA及HasA两个外分泌表达系统进行研究,从中筛选出HasA型血红素转运系统作为CSLH88菌株的外分泌表达系统,为后续外分泌杀虫毒素蛋白菌株构建以及CSLH88菌株的致病性研究奠定基础。国家重点研发计划课题(2017YFD0600105);;\n国家自然科学基金(31601905);;\n福建省科技厅自然科学基金(2016J01097);;\n福建省科技计划项目(2018N5002);;\n福建农林大学科研基金(xjq201614);福建农林大学林学院林学高峰学科项目(71201800720,71201800753,71201800779);;\n福建省大学生创新创业训练计划项目(201810389102);;\n福建省林业科学研究项目[Minlinke(2017)03]~

A Journey into the City. Migrant Workers' Relation with the Urban Space and Struggle for Existence in Xu Zechen's Early Jingpiao Fiction

In contemporary China, rural-urban migrants constitute a new urban subject with entirely new identity-related issues. This study aims at demonstrating how literature can be a valid field in investigating such evolving subjectivities, through an analysis of Xu Zechen’s early novellas depicting migrants’ vicissitudes in Beijing. Combining a close reading of the texts and a review of the main social problems characterising rural-urban migration in China, this paper focuses on the representation of the identity crisis within the migrant self in Xu’s stories, taking into account the network of meanings employed by the writer to signify the objective and subjective tension between the city and the countryside

复杂裂缝网络内支撑剂运移及铺置规律分析

水力压裂技术目前已广泛应用于页岩油气的开采中,为了提高产量,将支撑剂和携砂液按照不同的质量比混合注入裂缝,可形成支撑剂的有效铺置,从而提高裂缝的导流能力。支撑剂在复杂裂缝网络中的输送距离和铺置范围是衡量水力压裂效果的重要指标。采用室内模型实验,研究砂比、主裂缝与分支裂缝夹角以及支撑剂种类对支撑剂在复杂裂缝网络中运移和铺置规律的影响。结果表明:①随着砂比从3.0%增大到4.2%,主裂缝内支撑剂铺置高度与裂缝高度之比从0.44增大到0.465,分支裂缝内支撑剂质量与复杂裂缝网络中支撑剂质量之比从21%增大到25%。②随着主裂缝与分支裂缝夹角从90°减小到30°,分支裂缝内支撑剂质量与复杂裂缝网络中支撑剂质量之比从22%增大到30%。③支撑剂进入复杂裂缝网络的质量与实验所用支撑剂总质量之比随实验时间与总实验时间之比呈先快速增加后缓慢增加的趋势,当实验时间与总实验时间之比为0.6时,支撑剂进入复杂裂缝网络的质量与实验所用支撑剂总质量之比为65%~80%。④陶粒和自悬浮支撑剂在裂缝入口处的铺置效果不好,支撑剂铺置高度在主裂缝与分支裂缝相交处以及裂缝高度变化处有明显突变

离子交换基团接枝的多孔隔膜在液流储能电池中的应用

本发明涉及一种液流储能电池用离子交换基团接枝的多孔隔膜及其应用，所述的多孔隔膜是在以聚砜或聚醚砜有机高分子树脂为原料制备的多孔膜为基体，在多孔膜表面和/或孔内接枝离子交换基团制备而成，其中离子交换基团占多孔隔膜总质量的0.1-10wt.％。该类多孔隔膜制备方法简单，孔径可控，接枝程度可调，容易实现大批量生产，制备的接枝离子交换基团的多孔隔膜可有效提高电解液浸润性和离子传导率

一种水下腿履复合爬行底盘及应用其的水下机器人

本发明公开了一种水下腿履复合爬行底盘及应用其的水下机器人，涉及水下移动设备技术领域，解决了现有的水下机器人遇到障碍物时一般需要转向后绕开，由于其无法快速地跨过该障碍物，因此其缺乏在水中快速躲避障碍并保持快速行驶能力的问题，其技术方案要点是，包括：主架体、行驶机构、具有折叠状态和展开状态的折叠机构，其中折叠机构包括：第一转动装置、第一连杆、第二转动装置、第二连杆；第一连杆与第一转动装置传动连接；第二连杆与第二转动装置传动连接，第一连杆与第二连杆转动连接，本发明提供了一种新的水下快速移动的具体实施方式，其带可折叠式收纳功能、具有良好躲避障碍物能力、良好通过性、自由度高、结构简单、便于生产制造的优点

1470~1949年山东蝗灾的韵律性及其与气候变化的关系

基于历史文献中的蝗灾记录,重建了1470~1949年山东省蝗灾县数序列。结果表明:1470~1949年,山东蝗灾规模没有显著的增减趋势,而是呈准周期性变化,其中主要周期为:2~3年,准5年,10~11年,16~18年,26~28年,80~100年。进一步分析发现:虽然温度变化与蝗灾规模在年代际尺度上相关不显著,但温暖气候却是蝗灾大爆发的必要条件,而寒冷气候则会限制蝗灾规模。夏季降水的年际变化与蝗灾县数呈显著负相关,即夏季干旱有利于蝗灾的大规模发生。尽管自20世纪50年代以来,人为的治蝗活动可能已经明显地影响了蝗灾变化规律,但未来数十年内气候持续增暖对其的影响仍不容忽视

Intensity Change of Human Disturbance and Its Response to Landscape Pattern in the Yellow River Delta

The coastal wetlands of the Yellow River Delta is the most integral, broadest and youngest wetland ecosystem in the warm temperate zone of China. Also, it has unique ecological landscape as well as important ecological service functions. With the increase in population and the intensification of high- intensity development and construction activities, the sensitivity/fragility of the area is highlighted, which poses a great threat to the sustainable development of coastal areas. Aiming at the unique geographic location and resource characteristics of the Yellow River Delta, based on RS and GIS, the hemeroby model as well as the man-made ditches density were used in this study to intuitively reveal the temporal and spatial characteristics of human disturbance intensity in 1995,2004 and 2015 at the regional and local scales. The response of the wetland landscape pattern to human interference activities was explored as well. A grid analysis method was used to calculate the hemeroby index and man- made ditches density. The data source included the following: Landsat TM、ETM~+ and OLI Remote Sensing Data (30 m resolution) in 1995、2004、2015, SPOT image of 2004(5m resolution), GF-1 image of 2015 (2 m resolution) and topographic map. This study aims to provide decision support for ecological regulation and spatial control on human activities in coastal wetlands of the Yellow River Delta. The results showed that: (1) From 1995 to 2015,both the hemeroby index and the density of artificial ditches in the Yellow River Delta had increased significantly, and its spatial distribution showed a trend of expansion from the southwest to the east and north, and from inland to coastal areas; (2) With the increase of human activities, the area of natural wetlands in the study area have been decreased from 3232.11km~2 in 1995 to 2165.48km2 in 2015,the landscape diversity and spatial heterogeneity increased, ecological connectivity weakened, the plaque shape tended to be regular and simplistic. (3) The response of landscape pattern to hemeroby index varies regionally and temporally. In the Kenli Agricultural Area, Hekou Agricultural Area and Shengli Oil Field Area, where the intensity of human interference activities had been relatively high, the intensity increased significantly, and the regional landscape pattern changed obviously in different phases. In the Yiqianer Management Station and the Yellow River Estuary Management Station area, where the intensity of human interference activities had been relatively low, due to the increase in the density of artificial ditches, the landscape pattern had presented a decreasing trend in landscape diversity, patch complexity and ecological connectivity from 2004 to 2015. (4) The indices of hemeroby and the density of man-made ditches supplement each other and confirm each other, which can reflect the degree of human disturbance activities in the Yellow River Delta more comprehensively and objectively

体外循环术后肾损害原因及预后的回顾分析

【目的】分析体外循环术后肾损害的原因, 探讨其防治方法。【方法】对体外循环术后发生急性肾功能损害的31 例患者分为两组进行研究:Ⅰ , 死亡组24 例, Ⅱ , 治愈组7 例。【结果】两组体外循环后肾功能都有一定程度的损伤, 死亡组术 后低心排的持续时间和严重程度明显高于治愈组, P <0.05。【结论】术后低心排可能是造成急性肾功能衰竭和影响其预后 的主要因素, 控制高危因素, 防止轻-中度肾功能损害向严重肾功能衰竭发展, 是提高治愈率的关键。一旦发生急性肾功能衰 竭, 宜早期透析治疗