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克雷伯杆菌O852产trans-二氢香芹酮关键酶系提取工艺及酶学特性分析
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作者 王苗苗 李志 +14 位作者 杨金初 任婧楠 范刚 黄林华 李贵节 程玉娇 王秋领 杨永锋 黄珍珍 徐永明 李浩亮 付瑜锋 丁美宙 于爱群 冯剑 《现代食品科技》 北大核心 2026年第3期106-115,共10页
Trans-二氢香芹酮广泛应用于香精香料、医药、农业等领域,具有高经济价值。为了利用克雷伯杆菌O852进行柠檬烯的生物转化生产trans-二氢香芹酮,该实验对克雷伯杆菌O852产trans-二氢香芹酮关键酶体系的提取工艺及酶学特性进行分析。研究... Trans-二氢香芹酮广泛应用于香精香料、医药、农业等领域,具有高经济价值。为了利用克雷伯杆菌O852进行柠檬烯的生物转化生产trans-二氢香芹酮,该实验对克雷伯杆菌O852产trans-二氢香芹酮关键酶体系的提取工艺及酶学特性进行分析。研究通过单因素实验和响应面分析确定了细胞破碎的最佳条件,进一步分析金属离子、有机溶剂和抑制剂对酶活的影响,并测定酶的最适温度和pH值。研究发现,最佳的提取条件:超声时间21 min、料液比1:13、振幅36%。Fe^(2+)、Mn^(2+)、Zn^(2+)显著提升酶的活性,而Cu^(2+)和Fe^(3+)则表现出强烈的抑制效果。使用1%(V/V)的二甲基亚砜(Dimethyl Sulfoxide,DMSO)和异丙醇时,酶活性分别提升至121.64%和142.62%,然而,当增至5%(V/V)时,有机溶剂对酶活性的抑制作用增强,尤其是氯仿,其抑制效果最为显著。对于抑制剂的影响,乙二胺四乙酸(Ethylenediaminetetraacetic Acid,EDTA)对酶活性的抑制最显著,其他抑制剂也表现出一定的抑制效果。此外,研究得出酶的最适温度20℃,最适pH值9.0。结果为该酶体系的工业化应用提供了理论依据和技术支持。 展开更多
关键词 克雷伯杆菌 trans-二氢香芹酮 提取工艺 酶学特性
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基于Trans3D‑Net 的辐射源协同定位方法
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作者 于荣 王龙飞 《航天电子对抗》 2026年第1期27-33,共7页
提出一种基于深度学习的多接收站信息融合协同定位方法。该方法综合利用多个接收站获取的到达时间(TOA)、到达角(DOA)和接收信号强度(RSS)信息,创新性地构建了一种名为Trans3D‑Net的三维Transformer模型。该模型融合了3D卷积与3D Transf... 提出一种基于深度学习的多接收站信息融合协同定位方法。该方法综合利用多个接收站获取的到达时间(TOA)、到达角(DOA)和接收信号强度(RSS)信息,创新性地构建了一种名为Trans3D‑Net的三维Transformer模型。该模型融合了3D卷积与3D Transformer架构的优势,能够有效捕捉复杂传播环境下的时空长程依赖关系,显著提升定位精度与系统鲁棒性。 展开更多
关键词 辐射源定位 多接收站 trans3D‑Net 非视距(NLOS)
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Fusion Correction for China's Domestic Remote Sensing Data of Sea Ice Concentration Using the TransUnet Model
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作者 ZHAO Chunxiao YANG Yanrui +1 位作者 ZHU Guocan ZHU Hongchun 《Journal of Ocean University of China》 2026年第1期106-122,共17页
The rapid melting of Arctic sea ice poses significant risks to the safety of shipping routes.Accurate remote sensing data on sea ice concentration(SIC)is crucial for effective route planning of ships and ensuring navi... The rapid melting of Arctic sea ice poses significant risks to the safety of shipping routes.Accurate remote sensing data on sea ice concentration(SIC)is crucial for effective route planning of ships and ensuring navigational safety.Despite the availability of numerous SIC products in China,these datasets still lag behind mainstream international products in terms of data accuracy,spatiotemporal resolution,and time span.To enhance the accuracy of China's domestic SIC remote sensing data,this study used the SIC data derived from the passive microwave remote sensing dataset provided by the University of Bremen(BRM-SIC)as a reference to conduct a comprehensive evaluation and analysis of two additional SIC datasets:the dataset derived from the microwave radiation imager(MWRI)aboard the FY-3D satellite,provided by the National Satellite Meteorological Center(FY-SIC),and the dataset obtained through the DT-ASI algorithm from the microwave imager of the FY-3D satellite,provided by Ocean University of China(OUC-SIC).Based on the evaluation results,a TransUnet fusion correction model was developed.The performance of this model was then compared against Ordinary Least Squares(OLS),Random Forest(RF),and UNet correction models,through spatial and temporal analyses.Results indicate that,compared to FY-SIC data,the RMSE of the OUC-SIC data and the standard data is reduced by24.245%,while the R is increased by 12.516%.Overall,the accuracy of OUC-SIC data is superior to that of FY-SIC data.During the research period(2020–2022),the standard deviation(SD)and coefficient of variation(CV)of OUC-SIC were 3.877%and 10.582%,respectively,while those for FY-SIC were 7.836%and 7.982%,respectively.In the study area,compared with OUC-SIC data,FYSIC data exhibited a larger standard deviation of deviation and a smaller coefficient of variation of deviation across most sea areas.These results indicate that the OUC-SIC data exhibit better temporal and spatial stability,whereas the FY-SIC data show stronger relative dimensionless stability.Among the four correction models,all showed improvements over the original,unfused corrected data.The fusion corrections using the OLS,RF,UNet,and TransUnet models reduced RMSE by 5.563%,14.601%,42.927%,and48.316%,respectively.Correspondingly,R increased by 0.463%,1.176%,3.951%,and 4.342%,respectively.Among these models,TransUnet performed the best,effectively integrating the advantages of FY-SIC and OUC-SIC data and notably improving the overall accuracy and spatiotemporal stability of SIC data. 展开更多
关键词 sea ice concentration quality assessment fusion correction trans Unet model
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The utility of the trans-splenic retrocardiac view in supine critically ill patients
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作者 Issac Cheong Pablo Martín Merlo Francisco Marcelo Tamagnone 《World Journal of Emergency Medicine》 2026年第2期205-206,共2页
Monitoring cardiac function is a fundamental component of the diagnosis and management of critically ill patients.While pulmonary artery catheterization has long served as the standard for hemodynamic assessment,its i... Monitoring cardiac function is a fundamental component of the diagnosis and management of critically ill patients.While pulmonary artery catheterization has long served as the standard for hemodynamic assessment,its invasive nature and associated risks have shifted clinical practice toward non-invasive modalities.^([1]) Among these methods,point-of-care ultrasound(POCUS) has gained widespread acceptance,offering real-time bedside evaluation of cardiac function. 展开更多
关键词 cardiac function monitoring monitoring cardiac function hemodynamic assessmentits trans splenic retrocardiac view non invasive modalities cardiac function pulmonary artery catheterization supine critically ill patients
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基于小波域的复数卷积和复数Transformer的轻量级MR图像重建方法
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作者 张晓华 练秋生 《电子学报》 北大核心 2025年第4期1221-1231,共11页
卷积神经网络能够从大规模数据中学习图像先验信息,在图像处理领域具有优异表现,但局部感受野使其难以捕捉像素间的远程依赖关系. Transformer网络架构具有全局感受野,在自然语言和高级视觉问题上表现出色,但其计算复杂度与图像尺寸的... 卷积神经网络能够从大规模数据中学习图像先验信息,在图像处理领域具有优异表现,但局部感受野使其难以捕捉像素间的远程依赖关系. Transformer网络架构具有全局感受野,在自然语言和高级视觉问题上表现出色,但其计算复杂度与图像尺寸的平方成正比,限制了其在高分辨图像处理任务中的应用.此外,许多MR(Magnetic Resonance)图像重建算法仅使用幅值数据或将实部和虚部分离到两个独立的通道作为网络输入,忽略了复值图像实部和虚部之间的相关性.本文提出基于复数卷积和复数Transformer的混合模块,既能利用卷积神经网络提取的高分辨率空间信息恢复MR图像细节,又能通过自注意力模块获取的全局上下文信息捕获远程特征.基于混合模块,结合小波变换进一步提出基于小波域的复数卷积和复数Transformer的轻量级MR图像重建算法.在Calgary-Campinas和fastMRI两个数据集上的实验结果表明,所提出的模型与四种具有代表性的MR图像重建算法相比,具有更高的重建性能和更少的资源消耗.源代码公开于https://github.com/zhangxh-qhd/WCCTNet. 展开更多
关键词 MR图像重建 小波变换 轻量级网络 复数卷积 复数transformer 感受野
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基于1D-CNN和Transformer模型的道岔健康状态预测 被引量:1
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作者 陈俊竹 陈光武 +1 位作者 石建强 邢东峰 《北京交通大学学报》 北大核心 2025年第3期33-43,共11页
针对目前铁路道岔故障率高、维护效率低、健康状态难以预测等问题,以S700K型道岔转辙机为研究对象,提出一种基于一维卷积神经网络(One-dimensional Convolutional Neural Net-work,1D-CNN)和Transformer模型结合的道岔健康状态预测方法... 针对目前铁路道岔故障率高、维护效率低、健康状态难以预测等问题,以S700K型道岔转辙机为研究对象,提出一种基于一维卷积神经网络(One-dimensional Convolutional Neural Net-work,1D-CNN)和Transformer模型结合的道岔健康状态预测方法.首先,采用1D-CNN对原始数据进行特征提取,训练得到10组特征;然后,通过特征评价选择其中最能反映道岔健康状态的5组特征,利用它们与道岔功率曲线的健康标签值共同进行Transformer模型训练,得到预测的健康指数;最后,为评估道岔转辙设备的健康状态,采用Fisher最优分割算法对健康阶段进行划分,确定最优健康阶数为3,并针对不同健康阶段的维护工作给出指导性意见.研究结果表明:1D-CNN和Transformer模型的结合具有较为突出的预测效果与泛化能力,Transformer模型较门控循环单元(Gated Recurrent Unit,GRU)、长短期记忆网络(Long Short-Term Memory,LSTM)等常用模型在处理长时间序列数据时具有更好的表现,采用所提组合模型能得到更为准确的道岔健康状态预测结果,其平均绝对误差(Mean Absolute Error,MAE)、均方根误差(Root Mean Square Error,RMSE)较1D-CNN和LSTM的组合模型分别减小31.2%、30.5%. 展开更多
关键词 铁路道岔 一维卷积神经网络 transformer模型 健康状态预测 Fisher最优分割
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香豆素类天然产物trans-Dehydroosthol的全合成研究 被引量:1
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作者 韩伟 刘致文 +1 位作者 葛宝越 雷婷 《广东化工》 2025年第8期29-31,14,共4页
目的:以廉价易得的2-羟基-4-甲氧基苯甲醛为起始原料,通过简短的合成步骤以及简捷的操作方法,实现trans-dehydroosthol的高效全合成,进而为类似天然产物的合成提供有力支撑。方法:通过路易斯酸构建溴代底物、Perkin反应构建香豆素底物,... 目的:以廉价易得的2-羟基-4-甲氧基苯甲醛为起始原料,通过简短的合成步骤以及简捷的操作方法,实现trans-dehydroosthol的高效全合成,进而为类似天然产物的合成提供有力支撑。方法:通过路易斯酸构建溴代底物、Perkin反应构建香豆素底物,随后通过钯催化的Heck-dehydration反应高效引入异戊二烯基侧链,并对反应过程中的条件进行优化筛选。结果:以甲苯为溶剂、三正丙胺、三(二亚苄基丙酮)二钯、三叔丁基膦和2,6-二叔丁基-4-甲基苯酚,成功地利用最优条件以80.7%的高产率完成了天然产物trans-dehydroosthol的合成。结论:以2-羟基-4-甲氧基苯甲醛为起始原料,历经三步反应以总收率48.6%得到trans-dehydroosthol,操作简单,总收率高。 展开更多
关键词 trans-dehydroosthol 香豆素 Heck-dehydration 钯催化 全合成
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Ag^+-SPE/GC测定食物中trans C16:1,trans C18:1,trans C18:2和共轭亚油酸的含量 被引量:2
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作者 张妞 范亚苇 +2 位作者 于化泓 邓泽元 李静 《中国食品学报》 EI CAS CSCD 北大核心 2020年第9期286-295,共10页
为研究不同来源的反式脂肪酸(TFAs)对人体健康的影响,本文拟调查食物中trans C16:1,trans C18:1,trans C18:2和共轭亚油酸(CLA)异构体的组成和含量,为明确不同食物中TFAs和CLA与健康的关系提供科学理论依据。结合银离子固相萃取柱(Ag+-S... 为研究不同来源的反式脂肪酸(TFAs)对人体健康的影响,本文拟调查食物中trans C16:1,trans C18:1,trans C18:2和共轭亚油酸(CLA)异构体的组成和含量,为明确不同食物中TFAs和CLA与健康的关系提供科学理论依据。结合银离子固相萃取柱(Ag+-SPE)和GC色谱2种升温程序测定反刍动物油脂、食用油和煎炸油中trans C16:1,trans C18:1,trans C18:2和CLA异构体的含量。结果显示,从样品中共检测出23种TFAs,其中7种trans C16:1,10种trans C18:1,6种trans C18:2和6种CLA异构体。反刍动物油脂中trans C16:1,trans C18:1和CLA显著高于食用油和煎炸油,而煎炸油中trans C18:2含量较高。反刍动物油脂中9t C16:1,11t C18:1,9t12t C18:2是主要TFAs异构体,10t12c C18:2是主要的CLA异构体;而食用油和煎炸油中12t C16:1,9t C18:1,9c12t C18:2,9t12c C18:2为主要的TFAs异构体,10t12c C18:2和11c13t C18:2是CLA的主要异构体。通过食用油煎炸前、后脂肪酸的对比发现,茶籽油脂肪酸组成变化最小,而大部分煎炸油比未煎炸油中trans C18:2,trans C18:1的含量显著增加。可见,反刍动物油脂和食用油、煎炸油中主要TFAs异构体不同,而不同异构体脂肪酸对人体健康影响不同。茶籽油煎炸前后脂肪酸组成变化较小,食用中适合煎炸;而富含多不饱和脂肪酸的食用油经煎炸后会产生较多的对人体健康存在更大隐患的trans C18:2,因此对煎炸油品质的控制应引起有关生产和使用企业的高度重视。 展开更多
关键词 银离子固相萃取柱 trans C16:1 trans C18:1 trans C18:2 共轭亚油酸
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Analysis of risk factors for post-operative infection following drugeluting trans arterial chemo embolization in hepatocellular carcinoma:A retrospective study
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作者 Gang Wang Rui Qi 《World Journal of Gastrointestinal Surgery》 2025年第6期244-253,共10页
BACKGROUND Post-operative infection is a common and serious complication following drugeluting trans arterial chemo embolization(D-TACE)in patients with hepatocellular carcinoma(HCC),potentially compromising treatment... BACKGROUND Post-operative infection is a common and serious complication following drugeluting trans arterial chemo embolization(D-TACE)in patients with hepatocellular carcinoma(HCC),potentially compromising treatment efficacy and increasing morbidity.AIM To investigate the risk factors associated with post-operative infection in HCC patients undergoing D-TACE,and to provide evidence for clinical prevention and targeted intervention strategies.METHODS Clinical data of 77 primary HCC patients who underwent D-TACE in our hospital from January 2022 to December 2023 were retrospectively analyzed.Patient demographics,laboratory test results,tumor characteristics,and surgery-related parameters were collected.Univariate and multivariate logistic regression analyses were performed to identify risk factors for post-operative infection.RESULTS Post-operative infection occurred in 20 cases(25.97%)among the 77 patients.Univariate analysis showed that age≥65 years,Child-Pugh grade B,tumor diameter≥5 cm,operation time≥120 minutes,preoperative albumin<35 g/L,and comorbid diabetes were significantly associated with post-operative infection(P<0.05).Multivariate logistic regression analysis identified Child-Pugh grade B(OR=2.851,95%CI:1.426-5.698),operation time≥120 minutes(OR=2.367,95%CI:1.238-4.523),and preoperative albumin<35 g/L(OR=2.156,95%CI:1.147-4.052)as independent risk factors for post-operative infection.CONCLUSION Liver function status,operation time,and preoperative albumin level are significant factors affecting post-operative infection in HCC patients undergoing D-TACE.For high-risk patients,enhanced perioperative management,appropriate timing of surgery,and active improvement of nutritional status should be implemented to reduce the risk of post-operative infection. 展开更多
关键词 Hepatocellular carcinoma Drug-eluting trans arterial chemo embolization Post-operative infection Risk factors Retrospective study
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Introspective Study of Trans-Tibias Amputees in View of the Design of a Durable Prosthetic Foot
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作者 Boukar Abdelhakim Mahamat Maintah Ardjoune Debsi Edjibey 《Open Journal of Applied Sciences》 2025年第1期259-273,共15页
The prosthesis is an artificial device that can replace an organ of a human body member to restore a compromised function. It is necessary following the removal of a human organ, which can occur as a result of an illn... The prosthesis is an artificial device that can replace an organ of a human body member to restore a compromised function. It is necessary following the removal of a human organ, which can occur as a result of an illness, trauma or congenital malformation. The trans-tibia prosthesis, in particular, allows the amputee patient to recover the impaired function and regain autonomy, while facilitating their daily social integration. The trans-tibia prosthesis consists of a socket, a sleeve, connecting elements and a prosthetic foot. Each of these components plays a very important role. Among these components, the prosthetic foot usually called “SACH foot” is very often replaced due to cracking and therefore has a fairly short lifespan. At the Center for Equipment and Rehabilitation of Kabalaye (CERK), the SACH foot made using polyurethane and wood is imported and is given to patients with reduced mobility. The aim of this article is twofold, on the one hand, to make a social and pathological study of trans-tibia amputees in relation to the use of the SACH foot prosthesis, on the other hand, to compare this foot with a new prosthetic foot proposed and which is manufactured using extruded polystyrene. The result of prosthetic tests carried out on twenty-four amputees showed that the foot manufactured using extruded polystyrene is better in terms of resistance, bulk and adaptability to active amputees. 展开更多
关键词 Prosthesis Prosthetic Foot trans-Tibia Amputee SACH Foot
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Powdered activated carbon adsorption of two fishy odorants in water: Trans,trans-2,4-heptadienal and trans,trans-2,4-decadienal 被引量:10
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作者 Xin Li Jun Wang +1 位作者 Xiaojian Zhang Chao Chen 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2015年第6期15-25,共11页
Powdered activated carbon(PAC) adsorption of two fishy odorants, trans,trans-2,4-heptadienal(HDE) and trans,trans-2,4-decadienal(DDE), was investigated. Both the pseudo first-order and the pseudo second-order ki... Powdered activated carbon(PAC) adsorption of two fishy odorants, trans,trans-2,4-heptadienal(HDE) and trans,trans-2,4-decadienal(DDE), was investigated. Both the pseudo first-order and the pseudo second-order kinetic models well described the kinetics curves, and DDE was more readily removed by PAC. In isotherm tests, both Freundlich and Modified Freundlich isotherms fitted the experimental data well. PAC exhibited a higher adsorption capacity for DDE than for HDE, which could be ascribed to the difference in their hydrophobicity. The calculated thermodynamic parameters(ΔG^0, ΔH^0, and ΔS^0) indicated an exothermic and spontaneous adsorption process. PAC dosage, p H, and natural organic matter(NOM) presence were found to influence the adsorption process. With increasing PAC dosage, the pseudo first-order and pseudo second-order rate constants both increased. The value of p H had little influence on HDE or DDE molecules but altered the surface charge of PAC, and the maximum adsorption capacity occurred at p H 9. The presence of NOM, especially the fraction with molecular weight less than1 k Dalton, hindered the adsorption. The study showed that preloaded NOM impaired the adsorption capacity of HDE or DDE more severely than simultaneously fed NOM did. 展开更多
关键词 Adsorption mechanism Drinking water trans trans-2 4-decadienal trans trans-2 4-heptadienal
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A Study on Translation of Tourism Literature-from the Perspective of Skopos Theory 被引量:1
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作者 王雯 《海外英语》 2012年第12X期172-173,共2页
Tourism literature is a window for foreigners to know China and a medium for publicizing Chinese culture.Increasing the quality of translation of tourism literature is of great significance in promoting Chinese touris... Tourism literature is a window for foreigners to know China and a medium for publicizing Chinese culture.Increasing the quality of translation of tourism literature is of great significance in promoting Chinese tourisms' further development.This paper explores the strategies to deal with the translation of tourism literature,taking Skopos Theory as the theoretical base. 展开更多
关键词 TOURISM LITERATURE tranSLATION skopos THEORY tranS
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Anticancer Drug Resistance of HeLa Cells Transfected With Rat Glutathione S-transferase pi Gene 被引量:2
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作者 WEICAO YANMENG +3 位作者 QIANGWEI ZHAO-HUISHI LI-MEIJU FU-DEFANG 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2003年第2期157-162,共6页
To establish a cytologic expressing system of rat glutathione S-transferase pi (GST-pi) cDNA for detecting the resistance of HeLa cells to anticancer drugs. Methods The assessment was made with various anticancer dr... To establish a cytologic expressing system of rat glutathione S-transferase pi (GST-pi) cDNA for detecting the resistance of HeLa cells to anticancer drugs. Methods The assessment was made with various anticancer drugs (adriamycin, mitomycin, cisplatinum and vincristine) that showed different cytotoxicities in transfectant HeLa cells with pSV-GT containing rat GST-pi cDNA (HeLa/pSV-GT) or control pSV-neo (HeLa/pSV-neo). Expression levels of GST-pi mRNA in HeLa/pSV-GT and HeLa/pSV-neo were measured by in situ hybridization using Digoxin-labelled cDNA probe. Results HeLa/pSV-GT expressed significantly high degree of GST-pi mRNA, whereas both HeLa/pSV-neo and HeLa cells had very low expression. Cytotoxicities of HeLa/pSV-GT and HeLa/pSV-neo with 4 anticancer drugs were measured by MTT assay. Drug concentrations for yielding 50% inhibition (IC50) in HeLa/pSV-GT by adriamycin, mitomycin and cisplatinum were 70.13 靏/mL, 10.95 靏/mL and 16.52 靏/mL, respectively. In contrast, IC50 in HeLa/pSV-neo was 10.34 靏/mL, 7.48 靏/mL and 13.70 靏/mL, respectively. The cytotoxicities of vincristine on both HeLa/pSV-GT and HeLa/pSV-neo were not significantly different. Conclusions Our findings suggest that HeLa/pSV-GT containing rat GST-pi cDNA is resistant to some anticancer drugs due to overexpression of GST-pi. Also, HeLa/pSV-GT cell line could serve as a useful cytogenetic model for further research. 展开更多
关键词 Glutathione S-transferase P1 Enhancer element trans-acting factor Gene transfection Drug resistance Tumor cell In situ hybridization
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环肽中酰胺键cis-/trans-异构化的相关研究进展 被引量:2
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作者 黄净 杨毅华 +2 位作者 冯娟 李军章 刘守信 《有机化学》 SCIE CAS CSCD 北大核心 2020年第6期1473-1483,共11页
介绍了环肽化合物中顺式(cis-)和反式(trans-)结构特点,分别针对不含N-取代的环肽、含脯氨酸残基的环肽以及含N-甲基化残基的天然环肽,讨论了cis-或trans-结构在上述环肽及结构类似物中的研究进展,以及这种cis-或trans-结构对环肽生物... 介绍了环肽化合物中顺式(cis-)和反式(trans-)结构特点,分别针对不含N-取代的环肽、含脯氨酸残基的环肽以及含N-甲基化残基的天然环肽,讨论了cis-或trans-结构在上述环肽及结构类似物中的研究进展,以及这种cis-或trans-结构对环肽生物活性的潜在影响.脯氨酸由于其刚性吡咯环结构而显著影响着环肽分子构象,N-甲基化残基不仅增大了空间位阻,而且能够诱导增大酰胺键cis-结构比例. 展开更多
关键词 cis-/trans-结构 cis-/trans-异构体 环肽 生物活性
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News Translation and Intercultural Communication
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作者 肖成龙 《科技信息》 2014年第4期99-99,共1页
Challenges in translation can be approached from the perspective of intercultural communication, and translation also plays a major role in communication between cultures. The translators of news should be culture con... Challenges in translation can be approached from the perspective of intercultural communication, and translation also plays a major role in communication between cultures. The translators of news should be culture conscious and adopt flexible strategies in dealing with cultural differences. In news translation, the readability of the target language text counts the most. 展开更多
关键词 NEWS tranSLATION INTERCULTURAL COMMUNICATION tranS
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trans C_(18:1)通过NOS-NO系统诱导内皮细胞损伤研究 被引量:4
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作者 邱斌 刘蓉 +4 位作者 邓泽元 范亚苇 李静 胡蒋宁 黎玉 《食品科学》 EI CAS CSCD 北大核心 2011年第15期277-280,共4页
为了观察trans C18:1对人脐静脉内皮细胞损伤的影响及其与NOS-NO系统的关系,首先将不同浓度trans C18:1(50、100、200、400μmol/L)与人脐静脉内皮细胞共培养24或48h后,MTT法检测细胞存活率;用trans C18:1(200μmol/L)处理内皮细胞24h后... 为了观察trans C18:1对人脐静脉内皮细胞损伤的影响及其与NOS-NO系统的关系,首先将不同浓度trans C18:1(50、100、200、400μmol/L)与人脐静脉内皮细胞共培养24或48h后,MTT法检测细胞存活率;用trans C18:1(200μmol/L)处理内皮细胞24h后,分别检测一氧化氮含量(NO)及一氧化氮合酶(NOS)活性;将trans C18:1与一氧化氮合酶阻断剂亚硝酸左旋精氨酸甲酯(LNAME)及一氧化氮供体(SNP)单一或联合处理内皮细胞,检测细胞存活率的变化。结果显示:trans C18:1以剂量和时间依赖方式导致内皮细胞的存活率下降;LNAME与trans C18:1联合处理内皮细胞后细胞存活率下降,而SNP与trans C18:1联合处理后细胞存活率上升;trans C18:1可诱导NO水平和内皮型一氧化氮合酶(eNOS)活性显著下降,而诱导型一氧化氮合酶(iNOS)活性无显著改变。表明:trans C18:1能通过抑制eNOS活性减少NO的分泌,并暗示NOS-NO系统可能是trans C18:1诱导内皮细胞损伤的作用机制之一。 展开更多
关键词 tranS C18:1 人脐静脉内皮细胞 一氧化氮合酶 一氧化氮 损伤
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基于TransCAD的城市公交网络可达性指标及其应用 被引量:13
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作者 赵淑芝 匡星 +1 位作者 张树山 姜波 《交通运输系统工程与信息》 EI CSCD 2005年第2期55-58,共4页
对城市公共交通进行可达性分析,可以反映城市间不同区域通过公交线网的交通便捷程度.本文通过对乘客出行心理、行为的假设和公交线路、道路可达范围的界定,给出了一种简易的公共交通网络可达性指标计算公式,并基于Trans CAD软件给出了... 对城市公共交通进行可达性分析,可以反映城市间不同区域通过公交线网的交通便捷程度.本文通过对乘客出行心理、行为的假设和公交线路、道路可达范围的界定,给出了一种简易的公共交通网络可达性指标计算公式,并基于Trans CAD软件给出了指标计算方法步骤.最后,通过对长春市中心区的公交可达性进行了实证验算,得到了可信的结果. 展开更多
关键词 公交网络 tranSCAD软件 应用 城市公共交通 公共交通网络 可达性分析 出行心理 公交线网 公交线路 计算公式 方法步骤 指标计算 市中心区 道路
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八配位钇(Ⅲ)-反式-1,2-环己二胺四乙酸配合物NH_4[Y(trans-CYDTA)(H_2O)_2]·4.5H_2O的合成及分子结构 被引量:5
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作者 王君 张向东 +1 位作者 范大民 领小 《无机化学学报》 SCIE CAS CSCD 北大核心 2001年第5期755-759,共5页
In this paper, the molecular and crystal structures of the NH4[Y(trans CYDTA)(H2O)2]· 4.5 H2O(trans CYDTA=trans 1,2 cyclohexanediaminetetraacetic acid) are reported. The crystal data are as follows: Triclinic sys... In this paper, the molecular and crystal structures of the NH4[Y(trans CYDTA)(H2O)2]· 4.5 H2O(trans CYDTA=trans 1,2 cyclohexanediaminetetraacetic acid) are reported. The crystal data are as follows: Triclinic system, space group,a=0.8599(6)nm,b=1.0021(7)nm,c=1.4370(9)nm,α =88.095(13)° ,β =75.559(1)° ,γ =88.344(12)° ,V=1.1981(14)nm3,Z=2, M=708.68,Dc=1.570g· cm- 3, μ =2.506mm- 1 and F(000)=590. The final R1 and wR2 are 0.0571 and 0.1350 for 4205 [I >2.0σ (I)] unique reflections and 0.1007 and 0.1615 for all 4981 reflections, respectively. In the title complex, the anion [Y(trans CYDTA)(H2O)2]- has an eight coordination structure with distorted square antiprism. The trans CYDTA which acts as a hexadentate ligand with four O atoms and two N atoms and two H2O molecules directly coordinate to central metal Y? ion. It can be known that the Y? ion can form an eight coordinate compound with aminopolycarboxylic acid ligands in addition nine coordination structure. 展开更多
关键词 反式-1 2-环己二胺四乙酸 trans-CYDTA 合成 配合物 分子结构 钇(Ⅲ)配合物 放射性抗肿瘤药物
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毛细管气相色谱法测定乳脂中的cis-9,trans-11-共轭亚油酸 被引量:18
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作者 王小静 沈向真 +2 位作者 韩航如 赵茹茜 陈杰 《色谱》 CAS CSCD 北大核心 2006年第6期645-647,共3页
建立了测定乳脂中cis-9,trans-11-共轭亚油酸(CLA)的毛细管气相色谱方法。样品经正己烷-异丙醇提取、甲醇-甲醇钠甲酯化后,进行气相色谱分析;采用程序升温,以保留时间定性,外标法定量。采用该方法测得共轭亚油酸的回收率为100.26%,相对... 建立了测定乳脂中cis-9,trans-11-共轭亚油酸(CLA)的毛细管气相色谱方法。样品经正己烷-异丙醇提取、甲醇-甲醇钠甲酯化后,进行气相色谱分析;采用程序升温,以保留时间定性,外标法定量。采用该方法测得共轭亚油酸的回收率为100.26%,相对标准偏差(RSD)为1.9%(n=6),检测限为1 mg/L。该方法样品用量少,前处理简单,建立的实验条件准确可靠,不仅可以用来测定cis-9,trans-11-CLA的含量,而且对于乳制品中所含的其他脂肪酸的分析测定也具有指导意义。 展开更多
关键词 毛细管气相色谱法 cis-9 trans-11-其轭业油酸 乳脂
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β-环糊精衍生物诱导H_2O_2水相不对称环氧化trans-查尔酮 被引量:7
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作者 朱庆英 沈海民 纪红兵 《有机化学》 SCIE CAS CSCD 北大核心 2016年第8期1907-1914,共8页
以单(6-O-对甲苯磺酰基)-β-环糊精为原料,经亲核取代反应合成了氨基醇修饰的β-环糊精衍生物CD-1CD-6,收率在34%58%,结构通过1H NMR,13C NMR和ESI-MS表征确认.将β-环糊精衍生物CD-1CD-6应用于诱导水相H2O2不对称环氧化trans-查尔酮... 以单(6-O-对甲苯磺酰基)-β-环糊精为原料,经亲核取代反应合成了氨基醇修饰的β-环糊精衍生物CD-1CD-6,收率在34%58%,结构通过1H NMR,13C NMR和ESI-MS表征确认.将β-环糊精衍生物CD-1CD-6应用于诱导水相H2O2不对称环氧化trans-查尔酮,研究结果表明,β-环糊精衍生物的量和修饰基团结构对该反应体系的对映选择性有较大影响.其中,β-环糊精衍生物CD-1在诱导H2O2与Na HCO3组合水相不对称环氧化trans-查尔酮中效果最佳,ee值达到25.7%.通过2D-1H ROESY NMR表征发现,trans-查尔酮和CD-1之间可以形成包结络合物,同时CD-1CD-6均存在着修饰基团的自包结行为,影响产物ee值的提高,这两种包结形式均通过量子化学计算得到了映证. 展开更多
关键词 环糊精 不对称 环氧化 trans-查尔酮
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