期刊文献+
共找到1,088篇文章
< 1 2 55 >
每页显示 20 50 100
Outcomes of renal transplant recipients with BK virus infection and BK virus surveillance in the Auckland region from 2006 to 2012
1
作者 Chun-Yuan Hsiao Helen L Pilmore +1 位作者 Lifeng Zhou Janak R de Zoysa 《World Journal of Nephrology》 2016年第6期497-506,共10页
AIM To evaluate incidence, risk factors and treatment outcome of BK polyomavirus nephropathy(BKVN) in a cohort of renal transplant recipients in the Auckland region without a formal BK polyomavirus(BKV) surveillance p... AIM To evaluate incidence, risk factors and treatment outcome of BK polyomavirus nephropathy(BKVN) in a cohort of renal transplant recipients in the Auckland region without a formal BK polyomavirus(BKV) surveillance programme.METHODS A cohort of 226 patients who received their renal transplants from 2006 to 2012 was retrospectively reviewed.RESULTS Seventy-six recipients(33.6%) had a BK viral load(BKVL) test and 9 patients(3.9%) developed BKVN. Cold ischaemia time(HR = 1.18, 95%CI: 1.04-1.35) was found to be a risk factor for BKVN. Four recipients with BKVN had complete resolution of their BKV infection; 1 recipient had BKVL less than 625 copies/mL; 3 recipients had BKVL more than 1000 copies/mL and 1 had graft failure from BKVN. BKVN has a negative impact on graft function [median estimated glomerular filtration rate(eG FR) 22.5(IQR 18.5-53.0) mL /min per 1.73 m^2, P = 0.015), but no statistically significant difference(P = 0.374) in renal allograft function was found among negative BK viraemia group [median e GFR 60.0(IQR 48.5-74.2) mL /min per 1.73 m^2), positive BK viraemia without BKVN group [median eG FR 55.0(IQR 47.0-76.0) mL /min per 1.73 m^2] and unknown BKV status group [median eG FR 54.0(IQR 43.8-71.0) mL /min per 1.73 m^2]. The incidence and treatment outcomes of BKVN were similar to some centres with BKV surveillance programmes.CONCLUSION Recipients with BVKN have poorer graft function. Although active surveillance for BKV has been shown to be effective in reducing incidence of BKVN, it should be tailored specifically to that transplant centre based on its epidemiology and outcomes of BKVN, particularly in centres with limited resources. 展开更多
关键词 BK virus BK polyomavirus nephropathy Kidney transplantation Screening
下载PDF
Metformin associated lactic acidosis in Auckland City Hospital 2005 to 2009
2
作者 Imad Haloob Janak R de Zoysa 《World Journal of Nephrology》 2016年第4期367-371,共5页
AIM: To determine the incidence, clinical characteristics and outcomes of patients with metformin associated lactic acidosis (MALA).METHODS: Auckland City Hospital drains a population of just over 400000 people. A... AIM: To determine the incidence, clinical characteristics and outcomes of patients with metformin associated lactic acidosis (MALA).METHODS: Auckland City Hospital drains a population of just over 400000 people. All cases presenting with metabolic acidosis between July 2005 and July 2009 were identifed using clinical coding. A retrospective case notes review identifed patients with MALA. Prescribing data for metformin was obtained from the national pharmaceutical prescribing scheme.RESULTS: There were 42 cases of metabolic lactic acidosis over 1718000 patient years. There were 51000 patient years of metformin prescribed to patients over the study period. There were thirty two cases of lactic acidosis due to sepsis, seven in patients treated with metformin. Ten cases of MALA were identified. The incidence of MALA was estimated at 19.46 per 100000 patient year exposure to metformin. The relative risk of lactic acidosis in patients on metformin was 13.53 (95%CI: 7.88-21.66) compared to the general population. The mean age of patients with MALA was 63 years, range 40-83 years. A baseline estimated glomerular fltration rate was obtained in all patients and ranged from 23-130 mL/min per 1.73 m^2. Only two patients had chronic kidney disease G4.Three patients required treatment with haemodialysis. Two patients died. 展开更多
关键词 Acute kidney injury Lactic acidosis METFORMIN
下载PDF
康复机器人PVDF柔性关节设计与驱动特性研究
3
作者 谢光辉 孙红 +1 位作者 孙凡惟 王光建 《机械传动》 北大核心 2024年第5期164-168,共5页
针对康复机器人本体柔顺性差的问题,提出了一种新型的聚偏氟乙烯(Polyvinylidene Fluoride,PVDF)凝胶基人工肌肉,将其作为康复机器人柔性关节致动器,期望实现类人动作。介绍了PVDF凝胶制备和电致变形机制,并由此设计了具备收缩和伸张功... 针对康复机器人本体柔顺性差的问题,提出了一种新型的聚偏氟乙烯(Polyvinylidene Fluoride,PVDF)凝胶基人工肌肉,将其作为康复机器人柔性关节致动器,期望实现类人动作。介绍了PVDF凝胶制备和电致变形机制,并由此设计了具备收缩和伸张功能的单体肌肉,进而将多个单体肌肉上下串联,组合构成层级人工肌肉;基于康复机器人柔性关节3层级人工肌肉,辨识其驱动数学模型,并进行了仿真与实验。结果表明,该人工肌肉能够有效地实现位置控制,具备电致收缩和扩张能力,作为致动器应用于柔性关节是可行的。 展开更多
关键词 PVDF凝胶 人工肌肉 电致形变 柔性关节
下载PDF
白虎加人参汤对2型糖尿病大鼠抗氧化应激作用及机制研究
4
作者 刘清 王芳 +2 位作者 张淑娟 RASIKA Gunarathne 严军虎 《陕西中医》 CAS 2024年第9期1166-1171,共6页
目的:研究白虎加人参汤(BHJRS)对2型糖尿病(T2DM)模型大鼠抗氧化应激的作用,并初步探讨其作用机制。方法:随机取8只SD大鼠作为对照组(NC组),其余SD大鼠采用高脂高糖联合低剂量腹腔注射STZ(45 mg/kg)制备T2DM大鼠模型。将成模大鼠随机分... 目的:研究白虎加人参汤(BHJRS)对2型糖尿病(T2DM)模型大鼠抗氧化应激的作用,并初步探讨其作用机制。方法:随机取8只SD大鼠作为对照组(NC组),其余SD大鼠采用高脂高糖联合低剂量腹腔注射STZ(45 mg/kg)制备T2DM大鼠模型。将成模大鼠随机分为模型(DM)组、阳性药[盐酸二甲双胍(Met),200 mg/kg]组、BHJRS高剂量组(BHJRS-H,BHJRS溶液37.8 g/kg)、BHJRS低剂量组(BHJRS-L,BHJRS溶液18.9 g/kg),连续给药8周。测定各组大鼠第0、2、4、6、8周空腹血糖(FBG),检测糖化血红蛋白(HbAlc)、胰岛素(INS)、丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)水平并计算ISI值,观察胰腺组织病理学形态变化;检测胰腺组织中B淋巴细胞瘤-2基因(Bcl-2)、胱天蛋白酶3(Caspase-3)、Bcl-2相关X蛋白(Bax)的mRNA和蛋白水平;检测胰腺组织中蛋白激酶B(AKT)/糖原合成激酶-3β(GSK-3β)/核因子NF-E2相关因子(Nrf2)信号通路关键蛋白的表达。结果:与DM组比较,Met组、BHJRS-H组和BHJRS-L组显著降低T2DM大鼠FBG、血清中HbAlc、MDA水平(P<0.05),显著升高血清中INS、CAT、SOD、GSH-Px水平和ISI值(P<0.05);显著上调胰腺组织中p-AKT/AKT、p-GSK-3β/GSK-3β、n-Nrf2、血红素加氧酶-1(HO-1)水平(P<0.05),显著下调Bax/Bcl-2、Caspase-3、n-Fyn水平(P<0.05),胰腺组织病理变化均不同程度改善。结论:BHJRS对胰腺组织有一定的抗氧化应激作用,其原因可能在于调节AKT/GSK-3β/Nrf2信号通路中相关蛋白的表达有关。 展开更多
关键词 2型糖尿病 白虎加人参汤 抗氧化应激 胰岛素抵抗 胰岛Β细胞
下载PDF
陕西省实体经济高质量发展水平测度与影响因素研究
5
作者 杨芳 霍沛妮 《渭南师范学院学报》 2024年第3期48-57,共10页
基于发展基本面和发展成果,构建评价指标体系,运用熵值法、多元回归模型测度和考察2012—2021年陕西省实体经济高质量发展水平及影响因素。研究结果显示:陕西省实体经济高质量发展综合指数稳中向上,但发展强度指数持续较低、稳定性指数... 基于发展基本面和发展成果,构建评价指标体系,运用熵值法、多元回归模型测度和考察2012—2021年陕西省实体经济高质量发展水平及影响因素。研究结果显示:陕西省实体经济高质量发展综合指数稳中向上,但发展强度指数持续较低、稳定性指数与竞争性指数波动明显、外向性指数和创新指数长期保持低位,生态发展水平呈现下降趋势;数字经济和数字金融显著促进陕西省实体经济高质量发展,人力资本水平和外商直接投资规模有一定程度正向影响,而市场化程度的作用较小。因此,应通过推动科技创新和产业创新,优化产业链,提升价值链;加快数字经济和数字金融建设、提高人力资本、吸引FDI、深化市场化改革等推动实体经济高质量发展。 展开更多
关键词 实体经济 高质量发展 数字经济 数字金融
下载PDF
南方根结线虫生防菌X-20的鉴定及其作用机制研究
6
作者 董海龙 路平 +4 位作者 翟浩臻 赵增旗 王莉 王建明 徐玉梅 《中国生物防治学报》 CSCD 北大核心 2024年第1期196-205,共10页
南方根结线虫是设施蔬菜上的重要植物病原物,但目前缺乏安全高效的生物防治措施。本研究从根结线虫罹病土壤中分离到一株生防菌X-20,其发酵液对南方根结线虫二龄幼虫校正死亡率达100%。通过形态学、生理生化特征和分子生物学方法将菌株X... 南方根结线虫是设施蔬菜上的重要植物病原物,但目前缺乏安全高效的生物防治措施。本研究从根结线虫罹病土壤中分离到一株生防菌X-20,其发酵液对南方根结线虫二龄幼虫校正死亡率达100%。通过形态学、生理生化特征和分子生物学方法将菌株X-20鉴定为荧光假单胞菌Pseudomonas fluorescens。菌株X-20发酵液处理南方根结线虫时,当处理浓度1 mg/mL,虫体出现扭曲、僵直变化,内部组织分解;处理1 h后,虫体波动频率降幅47.26%、头部摆动频率波动性变化、虫体弯曲频率成S型变化;处理24 h后,二龄幼虫的体长减少4.68%,口针增加7.64%,透明尾长增加83.90%;J2虫体体液出现外渗,且电导率随着处理浓度的增大和时间延长而增加;发酵液甲醇提取物1mg/mL处理虫体,6h后糖含量比对照增加39.10%,甘油含量比对照高出66.67%,可溶性蛋白含量降低55.73%。由此可见,荧光假单胞菌X-20菌株代谢产物通过破坏根结线虫体壁及虫体内部结构,引起虫体液渗漏,扰乱虫体内糖类、脂类、蛋白类代谢,造成虫体死亡。 展开更多
关键词 荧光假单胞菌 代谢产物 南方根结线虫 防治效果 生防机理
下载PDF
食源性活性物质稳态化及靶向递送载体的研究进展
7
作者 岳庆 史文鹏 +7 位作者 张春月 李星 刘翔宇 吕鸣春 张辉 袁育 杨志 李媛 《食品科学》 EI CAS CSCD 北大核心 2024年第19期272-286,共15页
食源性活性物质例如多酚、类胡萝卜素、功能蛋白、不饱和脂肪酸等,因具有多种生物活性而作为功能食品开发的重要组分。然而,由于这些活性物质具有难溶于水、稳定性差和肠道吸收率低等问题,导致其在食品工业中的应用受到了限制。研究人... 食源性活性物质例如多酚、类胡萝卜素、功能蛋白、不饱和脂肪酸等,因具有多种生物活性而作为功能食品开发的重要组分。然而,由于这些活性物质具有难溶于水、稳定性差和肠道吸收率低等问题,导致其在食品工业中的应用受到了限制。研究人员利用天然食品大分子构建递送载体,以提高活性物质的溶解性、稳定性和肠道吸收率。作为新型递送系统,智能响应型递送释放和定向载体可实现活性物质的精准靶向递送和可控释放,从而提高其生物利用率。此外,递送载体还能有效提高功能食品的营养附加值、改善感官特性和延长货架期。本综述探讨食源性活性物质的功能性质、应用难题以及稳态化递送策略,重点阐述目前常见的智能响应型递送载体的类型和作用机理。最后讨论递送载体在功能食品中的应用,并对未来食源性活性物质递送系统的研究进行展望。 展开更多
关键词 食源性活性物质 稳态化 递送载体 靶向控释 生物利用率 功能食品
下载PDF
大语言模型在电催化领域中的应用 被引量:1
8
作者 张成翼 王兴宇 王子运 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第4期7-14,共8页
大语言模型作为现代科技的杰出代表,已经在社会的各个领域产生了深远影响.这些模型由数十亿个神经元相互连接构建而成,集成了人类至今为止的丰富知识,具备与全球各地人们进行流畅、精确对话的卓越能力.其类人智能特性不仅使其能够应对... 大语言模型作为现代科技的杰出代表,已经在社会的各个领域产生了深远影响.这些模型由数十亿个神经元相互连接构建而成,集成了人类至今为止的丰富知识,具备与全球各地人们进行流畅、精确对话的卓越能力.其类人智能特性不仅使其能够应对现代社会的各种挑战,更在多个科学领域中展现出巨大的应用前景.然而,目前大语言模型广泛应用的潜力尚未被完全挖掘.本文旨在深入探讨现代大语言模型在电催化领域的潜在应用,以期阐明这些人工智能驱动的模型如何助力科研人员深化对催化学科的理解,并推动催化剂的智能设计.通过对大语言模型在电催化领域应用的系统研究,我们期望能够为未来的科研工作提供新的思路和方法.本文首先分析了传统的实验法和多尺度模拟方法在催化研究中的局限性,包括资源消耗大、实验周期长、研究进展缓慢以及受人类自身能力限制等问题.随后,着重探讨了大语言模型在电催化研究中的显著优势,如突破人类认知界限、理论上具备无限知识累积能力等.尽管大语言模型展现出巨大的潜力,但仍面临泛化能力与领域专业性之间的权衡、文本限制等挑战.为应对这些挑战,本文进一步介绍了多模态大语言模型的发展及其在电催化研究中的具体应用,包括与实验者的直接互动、基于实验反馈的持续优化、预训练模型的微调以及结合视觉编码器实现多模态数据融合等.最后,强调了多模态大语言模型在光谱分析、实验路径设计、过渡状态搜索、分子结构设计、催化剂优化和问题诊断等方面的巨大潜力.总之,多模态方法在催化领域具有广泛的应用前景,能够整合多种数据源,为催化剂设计、反应机理研究和反应条件优化提供强大的工具和技术支持.最后,本文展望了大语言模型在科学研究中的作用和未来发展趋势.大语言模型在知识积累和效率提升方面展现出了出色的能力,但在创造全新知识方面,或许还无法与科学先驱相提并论.展望未来,大语言模型应当与实验和模拟方法深度融合,以增强其预测能力和多模态学习能力.通过这样的结合,大语言模型将能够更全面地辅助科学研究者,进而推动科学研究更迅速地发展.这一发展趋势不仅有助于提升科学研究的效率和准确性,还将为科学领域带来更多的创新和突破. 展开更多
关键词 大语言模型 电催化 人工智能 多模态大语言模型
下载PDF
NLRP3 inflammasome plays a vital role in the pathogenesis of age-related diseases in the eye and brain 被引量:1
9
作者 Jack Jonathan Maran Odunayo Omolola Mugisho 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第7期1425-1426,共2页
Key points:With aging,there is increased nucleotide-binding oligomerization domain-(NOD-)like receptor(NLR) protein-3(NLRP3) activation in neural and ocular tissues.Activation of the NLRP3 inflammasome appears to be a... Key points:With aging,there is increased nucleotide-binding oligomerization domain-(NOD-)like receptor(NLR) protein-3(NLRP3) activation in neural and ocular tissues.Activation of the NLRP3 inflammasome appears to be a common denominator in the pathogenesis of age-related diseases of the eye and brain.Pharmacological inhibition of the NLRP3 inflammasome may be a potent therapy for preventing the development and progression of age-related eye and brain diseases. 展开更多
关键词 NLRP3 PATHOGENESIS inflam
下载PDF
轨下压电叠堆俘能器安装对车轨系统动力性能的影响
10
作者 杜承运 王建军 +1 位作者 金浩 汤丽华 《振动与冲击》 EI CSCD 北大核心 2024年第12期248-259,共12页
压电俘能技术已经在轨道交通领域受到广泛关注,但目前主要侧重于压电俘能器的结构设计。俘能器的安装会在轨道结构中附加新的装置,可能会对车轨系统动力性能产生一定影响,甚至会威胁行车安全。然而,俘能器的安装对车轨系统动力性能的影... 压电俘能技术已经在轨道交通领域受到广泛关注,但目前主要侧重于压电俘能器的结构设计。俘能器的安装会在轨道结构中附加新的装置,可能会对车轨系统动力性能产生一定影响,甚至会威胁行车安全。然而,俘能器的安装对车轨系统动力性能的影响鲜有报道。以轨下压电叠堆俘能器为研究对象,建立了车辆-轨道-俘能器耦合系统的动力分析模型,构建了安装单个或多个俘能器下钢轨和道床的垂向振动方程,采用MATLAB软件编写了新型预测-校正积分法程序,给出了理论解答。通过与已有文献的结果对比,验证了程序的正确性。进一步,探究了采用单个和多个安装方式时俘能器的等效刚度对车轨系统动力性能(钢轨位移、钢轨加速度、扣件力和车体加速度)的影响,并评估了等效刚度与列车舒适度的关系。结果表明:当俘能器等效刚度在0~60×10^(6)N/m变化时,随着俘能器等效刚度的增加,两种安装方式的最大钢轨位移减小,钢轨加速度减少,车体加速度几乎保持不变,扣件力减小,列车行驶的舒适度呈现微小变化;当俘能器的等效刚度在0~2×10^(6)N/m选取时,俘能器的安装对车轨系统动力性能影响很小。研究成果为轨下压电叠堆俘能器的设计与安装提供了理论指导。 展开更多
关键词 压电俘能器 车轨系统 轨下 压电叠堆俘能器 动力性能
下载PDF
A core-satellite self-assembled SERS aptasensor containing a“biological-silent region”Raman tag for the accurate and ultrasensitive detection of histamine 被引量:1
11
作者 Chen Chen Yingfang Zhang +3 位作者 Ximo Wang Xuguang Qiao Geoffrey I.N.Waterhouse Zhixiang Xu 《Food Science and Human Wellness》 SCIE CSCD 2024年第2期1029-1039,共11页
Herein,a novel interference-free surface-enhanced Raman spectroscopy(SERS)strategy based on magnetic nanoparticles(MNPs)and aptamer-driven assemblies was proposed for the ultrasensitive detection of histamine.A core-s... Herein,a novel interference-free surface-enhanced Raman spectroscopy(SERS)strategy based on magnetic nanoparticles(MNPs)and aptamer-driven assemblies was proposed for the ultrasensitive detection of histamine.A core-satellite SERS aptasensor was constructed by combining aptamer-decorated Fe_(3)O_(4)@Au MNPs(as the recognize probe for histamine)and complementary DNA-modified silver nanoparticles carrying 4-mercaptobenzonitrile(4-MBN)(Ag@4-MBN@Ag-c-DNA)as the SERS signal probe for the indirect detection of histamine.Under an applied magnetic field in the absence of histamine,the assembly gave an intense Raman signal at“Raman biological-silent”region due to 4-MBN.In the presence of histamine,the Ag@4-MBN@Ag-c-DNA SERS-tag was released from the Fe_(3)O_(4)@Au MNPs,thus decreasing the SERS signal.Under optimal conditions,an ultra-low limit of detection of 0.65×10^(-3)ng/mL and a linear range 10^(-2)-10^5 ng/mL on the SERS aptasensor were obtained.The histamine content in four food samples were analyzed using the SERS aptasensor,with the results consistent with those determined by high performance liquid chromatography.The present work highlights the merits of indirect strategies for the ultrasensitive and highly selective SERS detection of small biological molecules in complex matrices. 展开更多
关键词 Surface-enhanced Raman spectroscopy Raman biological-silent region APTAMER Histamine detection Universal SERS-tag
下载PDF
Insights into microbiota community dynamics and flavor development mechanism during golden pomfret(Trachinotus ovatus)fermentation based on single-molecule real-time sequencing and molecular networking analysis 被引量:2
12
作者 Yueqi Wang Qian Chen +5 位作者 Huan Xiang Dongxiao Sun-Waterhouse Shengjun Chen Yongqiang Zhao Laihao Li Yanyan Wu 《Food Science and Human Wellness》 SCIE CSCD 2024年第1期101-114,共14页
Popular fermented golden pomfret(Trachinotus ovatus)is prepared via spontaneous fermentation;however,the mechanisms underlying the regulation of its flavor development remain unclear.This study shows the roles of the ... Popular fermented golden pomfret(Trachinotus ovatus)is prepared via spontaneous fermentation;however,the mechanisms underlying the regulation of its flavor development remain unclear.This study shows the roles of the complex microbiota and the dynamic changes in microbial community and flavor compounds during fish fermentation.Single-molecule real-time sequencing and molecular networking analysis revealed the correlations among different microbial genera and the relationships between microbial taxa and volatile compounds.Mechanisms underlying flavor development were also elucidated via KEGG based functional annotations.Clostridium,Shewanella,and Staphylococcus were the dominant microbial genera.Forty-nine volatile compounds were detected in the fermented fish samples,with thirteen identified as characteristic volatile compounds(ROAV>1).Volatile profiles resulted from the interactions among the microorganisms and derived enzymes,with the main metabolic pathways being amino acid biosynthesis/metabolism,carbon metabolism,and glycolysis/gluconeogenesis.This study demonstrated the approaches for distinguishing key microbiota associated with volatile compounds and monitoring the industrial production of high-quality fermented fish products. 展开更多
关键词 Fermented golden pomfret Microbiota community Volatile compound Co-occurrence network Metabolic pathway
下载PDF
一种上肢康复机器人肩关节减速器的传动精度分析及优化
13
作者 邹帅东 王光建 +3 位作者 谢光辉 侯景明 杨仁强 孙凡惟 《机械传动》 北大核心 2024年第7期137-142,共6页
基于上肢康复机器人的肩关节相对于其他上肢关节误差敏感性高及承载大的特点,采用一种渐开线少齿差行星减速器应用于其肩关节传动。考虑加工装配误差是造成传动误差的主要因素,运用啮合线增量法建立少齿差行星减速器传动误差的解析计算... 基于上肢康复机器人的肩关节相对于其他上肢关节误差敏感性高及承载大的特点,采用一种渐开线少齿差行星减速器应用于其肩关节传动。考虑加工装配误差是造成传动误差的主要因素,运用啮合线增量法建立少齿差行星减速器传动误差的解析计算模型;从统计学角度出发,采用蒙特卡洛法分析了偏心误差及其初始相位对上肢康复机器人肩关节传动精度的影响;基于肩关节传动精度解析模型,分析了传动误差造成的输出力矩波动;并在加工及装配精度不变的情况下,针对少齿差齿轮副各零件的偏心误差初始相位,采用粒子群优化算法进行传动精度优化,以改善上肢康复机器人肩关节传动精度及其造成的输出力矩波动,减少上肢康复患者可能由此造成的二次损伤。 展开更多
关键词 上肢康复机器人 肩关节减速器 传动精度 力矩波动
下载PDF
基于改进注意力机制CNN-ATT的区域性ZTD预测模型
14
作者 韦廖军 莫懦 +2 位作者 任晓斌 任宏权 魏二虎 《导航定位与授时》 CSCD 2024年第3期85-100,共16页
基于天顶对流层延迟(ZTD)的强时空特征,提出了一种融合卷积神经网络的改进注意力机制(CNN-ATT)的多站点ZTD组合预测模型。该模型首次将多源数据(包括日解算精度、年积日(DOY)和三维坐标)综合运用于ZTD预测任务。通过对南宁市的5个参考站... 基于天顶对流层延迟(ZTD)的强时空特征,提出了一种融合卷积神经网络的改进注意力机制(CNN-ATT)的多站点ZTD组合预测模型。该模型首次将多源数据(包括日解算精度、年积日(DOY)和三维坐标)综合运用于ZTD预测任务。通过对南宁市的5个参考站(CORS)和14个国际GNSS服务(IGS)站点共1501个年积日的观测数据进行研究,选取传统BP模型、GPT2w模型和ATT模型作为基线模型进行实验对比分析。研究结果显示,在预测精度方面,改进的CNN-ATT模型与BP模型相比其均方误差(MSE)和平均绝对误差(MAE)分别减少了5.5mm和4.4mm,预测精度分别提高了41.4%和67.8%;与ATT模型相比,CNN-ATT模型的预测MSE和MAE也分别减少了4.6mm和2.1mm,预测精度分别提升了36.2%和50.0%。在定位精度方面,改进的CNN-ATT模型的精度表现优于SAAS,GPT2w,BP以及ATT模型。并且与传统SAAS对流层模型相比,CNN-ATT模型在N,E,U3个方向的精度提升高达18.2%,12.6%和31.0%。此外,研究还发现CNN-ATT模型在长预测时间步长中的精度表现更为稳定,更适合多测站预测任务,并且其精密单点定位(PPP)收敛速度更快。 展开更多
关键词 注意力机制 对流层延迟 预测模型 卷积神经网络
下载PDF
抗战时期翻译员训练班探析
15
作者 霍雨佳 李洋 《长春师范大学学报》 2024年第5期90-96,共7页
抗日战争时期,中国开展了大规模的译员征调活动,培养出大批战时军事译员,成功地满足了当时中国军队的翻译服务需求。为了培养军事译员,政府组建了翻译员训练班。经过译训班培训的翻译员,帮助中国军队排除了与国际盟军的沟通障碍,保证战... 抗日战争时期,中国开展了大规模的译员征调活动,培养出大批战时军事译员,成功地满足了当时中国军队的翻译服务需求。为了培养军事译员,政府组建了翻译员训练班。经过译训班培训的翻译员,帮助中国军队排除了与国际盟军的沟通障碍,保证战时所需。这些翻译员在战后投身各类行业中,在技术引进和国际交流等方面发挥作用。 展开更多
关键词 抗战时期 军事翻译 译训班 译员培训
下载PDF
Spinal intradural electrodes: opportunities, challenges and translation to the clinic
16
作者 Bruce Harland Chien Yew Kow Darren Svirskis 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第3期503-504,共2页
Damage to the spinal cord disrupts the electrically active nerve cells which normally transmit afferent and efferent signals,resulting in loss of motor,sensory,and autonomic functions.Potential treatments for spinal c... Damage to the spinal cord disrupts the electrically active nerve cells which normally transmit afferent and efferent signals,resulting in loss of motor,sensory,and autonomic functions.Potential treatments for spinal cord injury utilizing implanted spinal electrodes can be broadly classified into three different categories.The first of these approaches is“spinal stimulation”where electrodes,usually positioned above the level of injury,provide electrical stimulation to target and disrupt pain signals before they reach the brain.The second approach uses“activity-dependent neuro-technologies”,in which electrodes positioned below the level of injury initiate a complex spatiotemporal pattern of stimulation at the lumbar spinal cord to generate a walking gait in the limbs(Minev et al.,2015;Wagner et al.,2018). 展开更多
关键词 STIMULATION ELECTRODES utilizing
下载PDF
Polypyrrole-coated triple-layer yolk-shell Fe_(2)O_(3)anode materials with their superior overall performance in lithium-ion batteries
17
作者 Zhen He Jiaming Liu +5 位作者 Yuqian Wei Yunfei Song Wuxin Yang Aobo Yang Yuxin Wang Bo Li 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第12期2737-2748,共12页
Iron oxide(Fe_(2)O_(3))emerges as a highly attractive anode candidate among rapidly expanding energy storage market.Nonethe-less,its considerable volume changes during cycling as an electrode material result in a vast... Iron oxide(Fe_(2)O_(3))emerges as a highly attractive anode candidate among rapidly expanding energy storage market.Nonethe-less,its considerable volume changes during cycling as an electrode material result in a vast reduced battery cycle life.In this work,an ap-proach is pioneered for preparing high-performance Fe_(2)O_(3)anode materials,by innovatively synthesizing a triple-layer yolk-shell Fe_(2)O_(3)uniformly coated with a conductive polypyrrole(Ppy)layer(Fe_(2)O_(3)@Ppy-TLY).The uniform polypyrrole coating introduces more reac-tion sites and adsorption sites,and maintains structure stability through charge-discharge process.In the uses as lithium-ion battery elec-trodes,Fe_(2)O_(3)@Ppy-TLY demonstrates high reversible specific capacity(maintaining a discharge capacity of 1375.11 mAh·g^(−1)after 500 cycles at 1 C),exceptional cycling stability(retaining the steady charge-discharge performance at 544.33 mAh·g^(−1)after 6000 ultrafast charge-discharge cycles at a 10 C current density),and outstanding high current charge-discharge performance(retaining a reversible ca-pacity of 156.75 mAh·g^(−1)after 10000 cycles at 15 C),thereby exhibiting superior lithium storage performance.This work introduces in-novative advancements for Fe_(2)O_(3)anode design,aiming to enhance its performance in energy storage fields. 展开更多
关键词 Fe_(2)O_(3) structure design anode material lithium-ion battery
下载PDF
Optimizing prediction models for pancreatic fistula after pancreatectomy:Current status and future perspectives
18
作者 Feng Yang John A Windsor De-Liang Fu 《World Journal of Gastroenterology》 SCIE CAS 2024年第10期1329-1345,共17页
Postoperative pancreatic fistula(POPF)is a frequent complication after pancre-atectomy,leading to increased morbidity and mortality.Optimizing prediction models for POPF has emerged as a critical focus in surgical res... Postoperative pancreatic fistula(POPF)is a frequent complication after pancre-atectomy,leading to increased morbidity and mortality.Optimizing prediction models for POPF has emerged as a critical focus in surgical research.Although over sixty models following pancreaticoduodenectomy,predominantly reliant on a variety of clinical,surgical,and radiological parameters,have been documented,their predictive accuracy remains suboptimal in external validation and across diverse populations.As models after distal pancreatectomy continue to be pro-gressively reported,their external validation is eagerly anticipated.Conversely,POPF prediction after central pancreatectomy is in its nascent stage,warranting urgent need for further development and validation.The potential of machine learning and big data analytics offers promising prospects for enhancing the accuracy of prediction models by incorporating an extensive array of variables and optimizing algorithm performance.Moreover,there is potential for the development of personalized prediction models based on patient-or pancreas-specific factors and postoperative serum or drain fluid biomarkers to improve accuracy in identifying individuals at risk of POPF.In the future,prospective multicenter studies and the integration of novel imaging technologies,such as artificial intelligence-based radiomics,may further refine predictive models.Addressing these issues is anticipated to revolutionize risk stratification,clinical decision-making,and postoperative management in patients undergoing pancre-atectomy. 展开更多
关键词 Pancreatic fistula PANCREATICODUODENECTOMY Distal pancreatectomy Central pancreatectomy Prediction model Machine learning Artificial intelligence
下载PDF
Extended context-based semantic communication system for text transmission
19
作者 Yueling Liu Shengteng Jiang +5 位作者 Yichi Zhang Kuo Cao Li Zhou Boon-Chong Seet Haitao Zhao Jibo Wei 《Digital Communications and Networks》 SCIE CSCD 2024年第3期568-576,共9页
Context information is significant for semantic extraction and recovery of messages in semantic communication.However,context information is not fully utilized in the existing semantic communication systems since re-l... Context information is significant for semantic extraction and recovery of messages in semantic communication.However,context information is not fully utilized in the existing semantic communication systems since re-lationships between sentences are often ignored.In this paper,we propose an Extended Context-based Semantic Communication(ECSC)system for text transmission,in which context information within and between sentences is explored for semantic representation and recovery.At the encoder,self-attention and segment-level relative attention are used to extract context information within and between sentences,respectively.In addition,a gate mechanism is adopted at the encoder to incorporate the context information from different ranges.At the decoder,Transformer-XL is introduced to obtain more semantic information from the historical communication processes for semantic recovery.Simulation results show the effectiveness of our proposed model in improving the semantic accuracy between transmitted and recovered messages under various channel conditions. 展开更多
关键词 semantic communication extended context Transformer-XL
下载PDF
Does MgSO_(4) protect the preterm brain?Dissecting its role in the pathophysiology of hypoxic ischemic encephalopathy
20
作者 Robert Galinsky Laura Bennet Alistair J.Gunn 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第9期1861-1862,共2页
Mitigating preterm encephalopathy continues to be one of the greatest challenges in perinatal medicine.Preterm encephalopathy is associated with high mortality,serious morbidity,and significant socio-economic impacts ... Mitigating preterm encephalopathy continues to be one of the greatest challenges in perinatal medicine.Preterm encephalopathy is associated with high mortality,serious morbidity,and significant socio-economic impacts on the individuals,their families,and public health sectors and welfare systems that last a lifetime.The cost of disability associated with preterm brain injury continues to rise.Prevention of this injury,and disability,would significantly reduce this socioeconomic burden. 展开更多
关键词 ENCEPHALOPATHY mortality HYPOXIC
下载PDF
上一页 1 2 55 下一页 到第
使用帮助 返回顶部