四磨汤口服液SD大鼠长期毒性实验研究          下载免费PDF全文

刘正清  孔卫青  杨华 《应用海洋学学报》2020,36(8):163

目的：观察SD大鼠灌胃四磨汤口服液的长期毒性反应。方法：将120只SD大鼠随机分为四磨汤口服液高、中、低3 个剂量组和辅料对照组,连续灌胃给药13周,恢复期4周,观察各组大鼠实验过程中症状发生情况、体质量、血细胞计数[包括白细胞（WBC）、红细胞（RBC）、血红蛋白（HGB）、红细胞压积（HCT）、平均红细胞体积（MCV）、平均红细胞血红蛋白（MCH）、平均红细胞血红蛋白浓度（MCHC）]、血液生化指标[包括丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST）、总蛋白（TP）、白蛋白（ALB）、白蛋白/球蛋白（A/G）、直接胆红素（TBil）、尿素氮（BUN）、肌酐（Cre）、总胆固醇（CHO）、三酰甘油（TG）]的变化,并观察停药后各指标的恢复情况。结果：四磨汤口服液高、中、低剂量组实验期间均未出现异常症状。与同期同性别辅料对照组相比,末次给药后次日高剂量组雌性大鼠RBC和HGB指标降低（P<0.05）,其他指标和时间点差异均无统计学意义（P＞0.05）。由于RBC和HGB变化幅度较小,均在正常参考值范围内波动,其他红细胞相关指标也未见异常改变,故认为该变化无重要的毒理学意义。各剂量组雄性大鼠血细胞计数指标均未见统计学差异（P＞0.05）。与同期同性别辅料对照组相比,末次给药后次日,高剂量组雄性大鼠BUN、雌性大鼠Cre降低,雄性大鼠CHO升高;与同期同性别辅料对照组相比,末次给药后次日,中剂量组雄性大鼠CHO升高;恢复期结束后,雄性大鼠TBil升高;与辅料对照组相比,恢复期结束后,雌性动物TG降低;上述指标差异均有统计学意义（P<0.05）。以上指标中,CHO、TBil的升高未见明显的剂量-反应关系,且在正常参考值范围内波动,认为无重要的毒理学意义。BUN、Cre、TG的降低无重要的毒理学意义。结论：本实验未见明显不良反应的剂量为45 g/kg,表明四磨汤口服液安全性高。  相似文献   

鄂尔多斯盆地南缘延安地区中深层地热能特征研究     

申小龙  王少锋  宋一民  王伟 《中国煤炭地质》2020,(1):37-41

近年来水热型、浅层地热能发展产生的缺点问题日益突出,以取热不取水为原则,中深层U型水平对接换热技术成为新的技术方向。通过对鄂尔多斯盆地南缘延安地区地层岩性、地温梯度特征、热储层特征等特征研究,分析了研究区中深层地热资源潜力,研究结果表明鄂尔多斯盆地南缘奥陶系马家沟组为良好的热传导型热储,深部地温梯度为3.05℃/100m。当马家沟组深度在3157m时,对应温度达到110.67℃。测井及注水试验结果表明,奥陶系马家沟组为极弱含水层,几乎没有流体,属于良好的干热岩型地热资源,具有较高的开采价值。充分确定了该区地热地质条件良好、地热资源潜力巨大。为合理、高效开发利用该区地热资源提供了科学依据,对进一步开发利用该区的地热能具有重要意义。  相似文献   

地热系统作用下红层软岩力学性能试验研究     

周其健  马德翠  邓荣贵  康景文  祝全兵 《岩土力学》2020,41(10):3333-3342

地热能源是目前绿色建筑的发展趋势，但红层软岩分布地区出现的系列建筑地基病害问题与地源热系统关系尚不清楚。依托成都某建筑群事故调查项目，研究了有无地热系统作用下泥岩、石膏岩的工程特性，并基于室内试验模拟，研究了不同加热方式、不同温度及不同浸水时间等因素下岩石宏观力学特性和微观结构特征。结果表明：（1）同一场地有无地热系统对岩石力学性质影响甚微，但有地热系统时岩体中裂隙发育数量明显增多，累积张开度明显增大；（2）随着浸泡时间增加，泥岩最大含水率可达30%以上，石膏岩含水率超不过15%，泥岩浸水软化效应较石膏岩显著，二者力学指标随含水率增加呈负指数型下降，石膏岩因晶粒大小不同，离散性大；（3）天然状态下石膏岩呈脆性破坏，泥岩呈延性破坏，石膏岩水岩界面溶蚀作用效应显著，随着石膏岩由表及里溶蚀加剧，温度变化效应对岩体内生裂隙萌发起一定促进作用；（4）在20～50 ℃温度变化范围内，石膏岩抗压强度随温度呈抛物线变化，而泥岩单调升高；（5）地热管与岩体间填筑不密实容易形成渗水通道，改变水动力条件，动水作用下使石膏岩裂隙及软弱夹层溶蚀加剧，形成更大空洞，从而诱发沉降。  相似文献   

胶东金矿床中关键金属超常富集特征与机理初探   总被引：7，自引：7，他引：0  

杨立强  李瑞红  高雪  邱昆峰  张良 《岩石学报》2020,36(5):1285-1314

胶东是全球唯一已知发育于前寒武纪变质地体内的晚中生代巨型金矿省,也是当今世界仅有的探明金资源储量超过5000吨的三个金矿省之一,被视为检验巨型金矿床成矿新理论和新模型的关键地区。胶东金矿床长期的开发和研究主要聚焦于金,对其共/伴生关键金属尚缺乏关注;但广泛发育含关键元素Te、Re、W、Zr、Cr、La、Ce、Sb、Bi和As的独立矿物。通过对胶东典型金矿床内关键元素赋存状态的分析,发现它们主要以微米矿物集合体、纳米颗粒或类质同象固溶体的形式出现,且空间分布极不均匀。通过对12个典型金矿床内关键元素的含量分布和富集特征的初步研究表明,相对于华北克拉通的地壳元素丰度,本次分析的Cr、Co、Cd、Rb、Nb、Ta、Hf、W、Sn、Sb、Bi、As和除Ho之外的其它15种REE均发生了不同程度富集。其中,Sb超常富集与Au共生形成浅成造山型金锑矿床,暗示该区可能成为重要锑资源接替区; Cd、Co、Nb、Rb、As和Bi超常富集达到伴生组分综合评价品位,显示出良好的资源潜力,尤其是Cd已具备综合利用的资源条件; Cr、Se、Te、Re、W和LREE超常富集接近伴生组分综合评价品位或已发现超常富集的载体矿物,可作为未来潜在的接替资源;而Ta、Hf、Sn和HREE远低于伴生组分综合评价品位,且载体矿物过于稀少和细小或尚未被发现,发生超常富集的可能性相对较低。虽然目前对胶东金矿床中关键元素赋存状态和分布规律的研究极其薄弱,对其超常富集机理的研究尚属空白;但胶东金成矿系统的勘查和研究积累厚实、资料丰富,且其内蕴藏的矿石量巨大、已有矿业基础设施和选矿设备完善、选矿工艺先进。深入研究胶东金矿床中关键元素源-运-聚超常富集机理,可为丰富"非常规类型关键元素成矿系统"理论体系和胶东及类似金矿床中关键元素的综合利用提供理论基础。  相似文献   

Quantifying and modelling urban stream temperature: a central US watershed study          下载免费PDF全文

Sean Zeiger  Jason A. Hubbart  Stephen H. Anderson  Michael C. Stambaugh 《水文研究》2016,30(4):503-514

Hydrologic models that rely on site specific linear and non‐linear regression water temperature (T_w) subroutines forced solely with observed air temperature (T_a) may not accurately estimate T_w in mixed‐use urbanizing watersheds where hydrogeological and land use complexity may confound common T_w regime assumptions. A nested‐scale experimental watershed study design was used to test T_w model predictions in a representative mixed‐use urbanizing watershed of the central USA. The linear regression T_w model used in the Soil and Water Assessment Tool (SWAT), a non‐linear regression T_w model, and a process‐based T_w model that accounts for watershed hydrology were evaluated. The non‐linear regression T_w model tested at a daily time step performed significantly (P < 0.01) better than the linear T_w model currently used in SWAT. Both regression T_w models overestimated T_w in lower temperature ranges (T_w < 10.0 °C) with percent bias (PBIAS) values ranging from ?28.2% (non‐linear T_w model) to ?66.1% (linear regression T_w model) and underestimated T_w in the higher temperature range (T_w > 25.0 °C) by 3.2%, and 7.2%, respectively. Conversely, the process‐based T_w model closely estimated T_w in lower temperature ranges (PBIAS = 4.5%) and only slightly underestimated T_w in the higher temperature range (PBIAS = 1.7%). Findings illustrate the benefit of integrating process‐based T_w models with hydrologic models to improve model transferability and T_w predictive confidence in urban mixed‐land use watersheds. The findings in this work are distinct geographically and in terms of mixed‐land use complexity and are therefore of immediate value to land‐use managers in similarly urbanizing watersheds globally. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

The sustainable development goals: A case study     

《Marine Policy》2017

The Sustainable Development Goals or SDGs [44] are an ambitious step towards sustainable development, taking a much broader view of sustainability than ever achieved previously, yet practical challenges remain, including how to implement change. The aims of this research were to determine how an influential aquaculture company in Australia - Tassal, Tasmania's largest salmon aquaculture company - perceived the SDGs, and to ascertain the motivations and barriers for Tassal to work towards implementing the goals. Interviews were conducted with leaders, employees and external business partners. Tassal was not aware of the SDGs prior to this project, but were open to considering implementing them in their current sustainability practices. The survey responses were analysed using the Values-Rules-Knowledge (vrk) framework of decision making. Key findings were: 1) corporate and personal values were the key component driving Tassal's positive responses to the SDGs; 2) awareness of the SDGs resulted in Tassal recognising the potential gains from engaging with some of the seemingly less aquaculture-related goals (such as health and wellbeing). These findings demonstrate that businesses can fruitfully engage with the SDGs, even without government requirements or societal expectations, if they are prepared to broaden their interpretation of business sustainability and be reflective about their values. The vrk model is a potentially useful addition to current SDG and sustainability tools, such as those of the UN Global Compact, as a way to diagnose organisational barriers to adopting practices aligned with the SDGs. An emerging area of importance to social, economic and environmental sustainability – social license – was also identified as implicit in many, but not explicit in any of the SDGs.  相似文献   

Reestimating a minimum acceptable geocoding hit rate for conducting a spatial analysis     

Álvaro Briz-Redón  Francisco Martinez-Ruiz  Francisco Montes 《International journal of geographical information science》2020,34(7):1283-1305

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基于文献计量方法的国内外城市更新比较研究   总被引：1，自引：1，他引：0  

孙威  王晓楠  盛科荣 《地理科学》2020,40(8):1300-1309

采用文献计量方法，利用Citespace工具对国内外城市更新研究进行知识图谱分析，从演化过程、发文期刊和研究机构的特征、研究热点等方面对比国内外城市更新研究的差异。研究表明：① 国内外城市更新研究的发文量呈现波动上升的趋势，在快速发展阶段尤为显著，每年发文量分别达到117篇和238篇；② 研究文献多集中在城市规划、区域研究、城市设计、建筑学等期刊。相对于国外，国内发文期刊更集中。国内排名前10的期刊发文量占比达46.65%，国外仅29.84%；③ 国内外的研究机构间初步形成合作网络，但网络联系与合作程度依然较低。相对于国外，国内研究机构间联系更紧密。④ 国外研究热点集中在伙伴关系与公众参与、绅士化、可持续发展、城市转型和文化创意等方面，国内研究热点体现在旧城改造与房地产开发、历史街区和工业遗产的保护与更新、广州?深圳城市更新的探索与实践、公众参与的初步探讨等方面。  相似文献   

Numerical study of effect of fluke inclination on behavior of drag anchor in clay with linearly increasing shear strength under unidirectional and combined loading     

《Applied Ocean Research》2019

Drag anchor is a widely used anchor type in offshore engineering for the mooring system. The prediction of the anchor trajectory installation and the final position is important for anchor selection in design. The existing method using yield envelope method for trajectory prediction ignored the shallow anchor behavior but applied the deep yield envelope from a deeply embedded horizontal fluke in uniform clay for the whole drag-in installation process. However, the anchor fluke embedment depth and inclination angle change continually during installation in clay with linearly increasing shear strength soil profile in practice. Studies on the effect of fluke inclination angle on the anchor behavior in clay with such non-uniform soil profile under unidirectional and combined loading are important and necessary for the improvement of the yield envelope method to ensure a reasonable prediction. The current 2D finite element studies investigate the anchor behavior for inclined fluke in clay with linearly increasing shear strength under unidirectional vertical, horizontal and rotational loadings first. Then the effects of the fluke inclination angle, soil non-homogeneity and embedment depth ratio on the shallow yield envelopes are investigated. It is found that the effect of fluke inclination angle on the vertical capacity factors for anchor in clay with non-uniform and uniform soil profile is largely different. The resultant large impact on the yield envelopes shown here illustrates the importance of considering the fluke inclination angle and soil non-homogeneity in the prediction of anchor trajectory using yield envelope method.  相似文献   

健脾益气方调控间隙连接蛋白43防治PD大鼠腹膜损伤的作用机制研究          下载免费PDF全文

孟立锋  杨端云  史伟 《应用海洋学学报》2020,36(7):157

目的：研究健脾益气方通过调控间隙连接蛋白（Cx）43干预腹膜透析大鼠腹膜间皮细胞转分化的作用机制。方法：将75只大鼠随机分为5组,即空白组、模型组、中药高剂量组、中药低剂量组、西药组,除空白组大鼠外,其余各组均采用5/6肾切除联合腹腔注射4.25％腹透液复制慢性肾衰竭腹膜纤维化大鼠模型。造模成功后,中药高、低剂量组给予健脾益气方,西药组给予阿托伐他汀钙,模型组给予0.9%氯化钠注射液,空白组不做任何处理。每天灌胃1次,连续4周。干预后光镜观察各组大鼠腹膜结构变化,测量腹膜致密层厚度;免疫组化法及蛋白质印迹法检测Cx43、蛋白激酶B/哺乳动物雷帕霉素靶蛋白（AKt/mTOR）通路和腹膜间皮细胞转分化（EMT）标志蛋白表达。结果：各组大鼠腹膜厚度及Cx43、pAKt、pmTOR、α平滑肌肌动蛋白（α-SMA）、E-钙黏附蛋白（E-cadherin）阳性面积比,空白组与模型组比较,中药高、低剂量组及西药组与模型组比较,中药高剂量组与西药组、中药低剂量组比较,差异均有统计学意义（P<0.05）。各组大鼠腹膜组织Cx43、pAKt、pmTOR、α-SMA、E-cadherin蛋白表达,空白组与模型组比较,中药高剂量组与西药组比较,差异均有统计学意义（P<0.05）。结论：健脾益气方可能通过调控Cx43表达,干预Akt/mTOR信号通路介导的腹膜间皮细胞EMT进程,从而发挥保护腹膜间皮细胞、防治腹膜损伤的作用。  相似文献