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Simultaneous determination of clopidogrel,2-oxo-clopidogrel,and the thiol metabolite of clopidogrel in human plasma by LC-MS/MS

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The Journal of Biomedical Research 2022年第2期36卷 109-119页

作者： Lei Xu Ran Li Juan Li Zhou Dong Jiaxin Zong Chuchu Tan Zekang Ye Lu Shi Xiaoxuan Gong Chunjian Li Department of Cardiology the First Affiliated Hospital of Nanjing Medical UniversityNanjingJiangsu 210009China Department of Cardiology the Affiliated Sir Run Run Hospital of Nanjing Medical UniversityNanjing Jiangsu 210009China Cardiovascular Center the Second Affiliated Hospital of Nanjing Medical UniversityNanjingJiangsu 210003China

Clopidogrel is a pro-drug which needs two-step metabolism to produce the active thiol metabolite.This study aimed to explore an efficient method to simultaneously determine the plasma clopidogrel,2-oxo-clopidogrel(2-Oxo-CLP),and the clopidogrel active metabolite(CAM).A high-throughput liquid chromatography tandem mass spectrometry(LC-MS/MS)was therefore developed.The analytes were extracted from plasma by using methyl tert-butyl ether(MTBE).Chromatographic separation was performed on a C18 column under an isocratic elution,accompanied with acetonitrile and deionized water containing 0.1%formic acid.After optimizing the condition of LC-MS/MS,a stable linearity was observed in the standard curves over the concentration ranges of 0.05 to 50.0 ng/mL for clopidogrel,0.5 to 50.0 ng/mL for 2-Oxo-CLP,and 0.5 to 100 ng/mL for clopidogrel active metabolite derivative(CAMD).The retention time was 4.78 minutes,3.79 minutes,3.59 minutes,and 4.82 minutes for clopidogrel,2-Oxo-CLP,CAMD,and internal standard,respectively.Both the relative standard deviation and the relative error were within the requirement of operating criteria.No significant degradation of clopidogrel,2-Oxo-CLP,and CAMD occurred under different storage conditions.This method was successfully validated in 3 patients with coronary artery disease.The results showed that the current LC-MS/MS method was efficient for simultaneously detecting clopidogrel,2-Oxo-CLP,and CAM with fine linearity,accuracy,precision,and stability.

关键词： clopidogrel drug metabolites liquid chromatography tandem mass spectrometry coronary artery disease

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串列海缆悬跨段的流场特性及防护措施研究

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实验室研究与探索 2022年第5期41卷 88-90,146页

作者：沈方超宗家欣浙江华东工程咨询有限公司杭州310000

随着海上风电场的建设,海底电缆冲刷悬跨问题逐渐显现,对风电场的安全运营造成威胁。以如东海上风电场项目为例,建立数值模型分析了单向流作用下串列海缆悬跨段的尾流特性。研究结果表明,串列海缆圆柱之间存在负压区,该区域内流速较大,... 详细信息

随着海上风电场的建设,海底电缆冲刷悬跨问题逐渐显现,对风电场的安全运营造成威胁。以如东海上风电场项目为例,建立数值模型分析了单向流作用下串列海缆悬跨段的尾流特性。研究结果表明,串列海缆圆柱之间存在负压区,该区域内流速较大,产生周期性的漩涡脱落,使得海缆后柱产生周期性作用力。为避免海缆在周期性力作用下的破坏,结合实际海况,提出采用柔性材料和压载管道方法进行海缆冲刷防护,所得结果可为相关海上风电场工程提供参考。

关键词：海缆悬跨流场特性冲刷防护

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Numerical Investigation of Three-dimensional Aeroacoustic Characteristics of Owl-inspired Trailing-edge Fringes

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Journal of Bionic Engineering 2023年第3期20卷 1103-1120页

作者： jiaxin Rong Hao Liu Shanghai Jiao Tong University and Chiba University International Cooperative Research Center(SJTU-CU ICRC) Shanghai200240China Graduate School of Engineering Chiba University1-33Yayoi-choInage-kuChiba263-8522Japan

Owls are widely known for their silent flight,which is attributed to their unique wing morphologies comprising leading-edge(LE)serrations,trailing-edge(TE)fringes,and a velvety surface.The aeroacoustic characteristics of owl-inspired TE fringes have been widely investigated through two-dimensional(2D)modeling,but remain yet poorly studied in association with their three-dimensional(3D)effects.Here,we present a numerical study of the 3D aeroacoustic characteristics of owl-inspired TE fringes in which we combined large-eddy simulations(LES)with the Ffowcs Williams‒Hawkings analogy.We constructed a clean wing model and three wing models with TE fringes that were distributed differently spanwise.The aerodynamic forces and 3D acoustic characteristics reveal that,like the 2D results of our previous studies,the 3D TE fringes enable remarkable sound reduction spatially while having aerodynamic performance comparable to the clean model.Visualizations of the near-field 3D flow structures,vortex dynamics,and flow fluctuations show that TE fringes can robustly alter the 3D flow by breaking 3D TE vortices into small eddies and mitigating 3D flow fluctuations.Particularly,it is verified that TE fringes alter spanwise flows,thus dominating the 3D aeroacoustic characteristics in terms of passive flow control and flow stabilizations,whereas the fringes are inefficient in suppressing the acoustic sources induced by wingtip vortices.Moreover,the TE fringes distributed at midspan have better acoustic performance than those in the vicinity of the wingtip,indicating the importance of a spanwise distribution in enhancing aeroacoustic performance.

关键词： Owl Three-dimensional trailing-edge fringes Aeroacoustics Large-eddy simulation Ffowcs Williams‒Hawkings equation

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融合张量合成注意力的改进ResNet图像分类模型

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激光与光电子学进展 2023年第6期60卷 87-96页

作者：邱云飞张家欣兰海宗佳旭辽宁工程技术大学软件学院辽宁葫芦岛125105 中国科学院海西研究院泉州装备制造研究所福建泉州362216 元启工业技术有限公司山东青岛266000

针对卷积神经网络处理图像分类任务时提取特征不充分以及提取到的特征不区分贡献度的问题,提出了一种融合张量合成注意力的改进ResNet-101(RTSA Net-101)网络模型.首先,利用ResNet-101骨干网络提取图像特征,并在残差网络卷积结构后嵌入... 详细信息

针对卷积神经网络处理图像分类任务时提取特征不充分以及提取到的特征不区分贡献度的问题,提出了一种融合张量合成注意力的改进ResNet-101(RTSA Net-101)网络模型.首先,利用ResNet-101骨干网络提取图像特征,并在残差网络卷积结构后嵌入张量合成注意力模块,对获取的特征进行三张量积计算,得到注意力特征矩阵;然后,使用Softmax函数对注意力特征矩阵进行归一化,从而为特征分配权重,以区分特征的贡献度;最后,将得到的权重和对应的键值加权求和,获取最终图像完整特征,以提升模型的图像分类精度.在自然图像数据集CIFAR-10、CIFAR-100和街牌号数据集SVHN上进行了对比实验,模型分类准确率分别为96.12%、81.60%、96.67%,图像平均测试运行时间分别为0.0258 s、0.0260 s、0.0262 s.实验结果表明:相比于其他7种先进图像分类模型,RTSA Net-101模型可以获得更高的分类准确率和更短的测试运行时间,且能够有效地增强网络的特征学习能力,具有一定的创新性、高效性.

关键词：张量合成注意力残差网络自注意力特征提取图像分类

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来源于类芽孢杆菌属新型耐有机溶剂脂肪酶的克隆、表达与性质研究（英文）

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Chinese Journal of Catalysis 2018年第5期39卷 937-945页

作者：高嘉心区晓阳徐培宗敏华娄文勇华南理工大学食品科学与工程学院广东广州510640 华南理工大学制浆造纸工程国家重点实验室广东广州510640

脂肪酶(EC 3.***.1.3)全称为三酰基甘油水解酶,是一类能够将长链脂肪酸甘油酯水解成脂肪酸和二甘酯、单甘酯或甘油的酯键水解酶.它除了能够水解脂肪外,还具有催化酯化反应、酯交换反应、酸解反应、醇解反应以及氨解等反应的性质.在脂肪酶... 详细信息

脂肪酶(EC 3.***.1.3)全称为三酰基甘油水解酶,是一类能够将长链脂肪酸甘油酯水解成脂肪酸和二甘酯、单甘酯或甘油的酯键水解酶.它除了能够水解脂肪外,还具有催化酯化反应、酯交换反应、酸解反应、醇解反应以及氨解等反应的性质.在脂肪酶催化的反应中,通常用有机溶剂代替水.有机溶剂可以转移合成反应的平衡方向,通过溶剂工程修饰酶的选择性能够提高底物的溶解度、有机相产物的回收率、酶的热稳定性.但有机溶剂对酶活性和稳定性有不同程度的影响.因此,寻找在有机溶剂中表现出高活性和稳定性的脂肪酶是一个亟待解决的重要课题.由于微生物种类多、作用底物专一性强,且微生物来源的脂肪酶一般分泌到胞外,因此微生物脂肪酶是工业用脂肪酶的重要来源.目前,微生物脂肪酶的研究主要集中于根霉属(Rhizopus)、曲霉属(Aspergillus)、青霉属(Penicillium)、毛霉属(Mucor)、地霉属(Geotrichum)、假丝酵母属(Candida)、假单胞菌属(Pseudomonas)、伯克霍尔德菌属(Burkholderia)等具有工业应用价值的菌株.很少有类芽孢杆菌属所产脂肪酶进行相关酶学性质的研究.我们以Paenibacillus pasadenensis CS0611为出发菌株,在全基因序列草图中得到了一个新型脂肪酶基因lp2252.以Paenibacillus pasadenensis CS0611基因组为模板,设计特异性引物对目标序列进行扩增,并成功将其插入到表达载体p ET-28a中得到含有目的基因的重组质粒.在E.coli BL21(DE3)中,脂肪酶lp2252经0.1mmol/L的IPTG诱导后在20°C实现了高水平表达.重组脂肪酶的活性约为野生型的1631倍.用镍离子亲和层析柱快速、高效地纯化了两端带有组氨酸标签的重组脂肪酶,回收率为63.5%,纯化因子为10.78.纯化后的脂肪酶最适温度为50°C,在20-40°C范围内具有良好的稳定性.最适pH值为7,属于中性脂肪酶,同时在pH 3.0-8.0间具有较高稳定性.在金属离子如钙、镁离子和一些非离子表面活性剂的作用下,其活性有所提高.此外,纯化后的脂肪酶可被一系列水溶性有机溶剂激活,例如一些短链醇.而对某些水不溶性有机溶剂,其也具有高度的耐受性.综上所述,本文所涉新型脂肪酶在非水相催化领域具有广泛的应用和前景.

关键词：脂肪酶类芽孢杆菌属表达酶学性质有机溶剂耐受性

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Optimal Formation Control for Second-Order Multi-Agent Systems With Obstacle Avoidance

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IEEE/CAA Journal of Automatica Sinica 2023年第2期10卷 563-565页

作者： jiaxin Zhang Wei Liu Yongming Li the State Key Laboratory of Synthetical Automation for Process Industries Northeastern UniversityShenyang 110000China the School of Computer Science and Engineering Northeastern UniversityShenyang 110000China IEEE the College of Science Liaoning University of TechnologyJinzhou 121001China

Dear Editor,The optimal formation control design problem is studied for a class of second-order multi-agent systems(MASs) with obstacle avoidance.Based on the actor-critic framework, an optimized formation controller is proposed by constructing a novel performance index function. Furthermore, the stability of MAS is proved by constructing the Lyapunov function. The simulation results are provided to depict the effectiveness of the proposed strategies.

关键词： function agent constructing

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Rapid identification of rice seed based on inverse Fourier transform of laser-induced breakdown spectroscopy

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Optoelectronics Letters 2022年第8期18卷 495-501页

作者： HOU jiaxin WANG Yang’en College of Physics and Optoelectronic Engineering Yangtze UniversityJingzhou 434023China

The identification of rice seeds is crucial for agriculture production.An inverse Fourier transform(IFT)method based on laser-induced breakdown spectroscopy(LIBS)is proposed to identify five kinds of rice seeds.The LIBS data of the samples were preprocessed by inverse fast Fourier transform(IFFT),and the time-domain signals of rice seeds were obtained.The back propagation(BP)neural network was used to establish full spectrum,segmented spectrum,time-domain full spectrum and time-domain segmented spectrum discrimination models.Compared with the original spectrum,the time-domain spectrum can significantly improve the identification accuracy.The time-domain full-spectrum identification accuracy reached 95.28%,and the time-domain segmented spectrum identification accuracy reached 94.36%,whose identification time was only a few seconds.The results demonstrate that LIBS detection technology combined IFFT and BP neural network is fast and accurate,which provides a new idea for batch detection of rice seeds.

关键词： inverse spectrum spectroscopy

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Methods to improve the quality of low-salt meat products:a meta-analysis

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Food Quality and Safety 2023年第2期7卷 205-216页

作者： jiaxin Yin Pangzhen Zhang Zhongxiang Fang School of Agriculture and Food Faculty of Veterinary and Agricultural SciencesThe University of MelbourneParkvilleVictoriaAustralia

Low-salt meat(salt content<2%)is gaining popularity for its lower health risks,while the food industry faces technical challenges in improving its quality.Twenty-one studies involving meat quality improvement measures in low-salt meat products were included in this meta-analysis.The outcomes of these studies were assessed to derive conclusions about their effects on meat hardness and cooking losses.The results demon-strated that higher power ultrasound treatments(300-1500 W)significantly increased the hardness of low-salt meat,while a similar outcome was also achieved by low-strength(50-200 MPa)high-pressure processing(HPP)treatment,which was beneficial for alleviating the undesirable too-soft texture of the low-salt meat products.Furthermore,when salt reduction was greater than 50%,the application of ultrasonic treatment.and HPP of 50-200 MPa significantly reduced the cooking losses,and the addition of hydrocolloids also increased the cooking yield of the salt-reduced meat products.Among all the interventions,HPP exhibited the most significant effects in low-salt meat quality improvement,which warrants future studies on the combination of this method with salt reduction strategies in the reduction of salt content in processed meat products.

关键词： Processed meat meat quality improvement ultrasound high-pressure processing hydrocolloids

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Study on site selection planning of urban electric vehicle charging station

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High Technology Letters 2024年第1期30卷 75-84页

作者：刘娜 CHENG jiaxin DUAN Yukai School of Business Shanghai Dianji UniversityShanghai201306 P.R.China

The large-scale development of electric vehicles(EVs)requires numerous charging stations to serve them,and the charging stations should be reasonably laid out and planned according to the charging demand of electric vehicles.Considering the costs of both operators and users,a site selection model for optimal layout planning of charging stations is constructed,and a queuing theory approach is used to determine the charging pile configuration to meet the charging demand in the planning area.To solve the difficulties of particle swarm global optimization search,the improved random drift particle swarm optimization(IRDPSO)and Voronoi diagram are used to jointly solve for the optimal layout of electric vehicles.The final arithmetic analysis verifies the feasibility and practicality of the model and algorithm,and the results show that the total social cost is minimized when the charging station is 9,the location of the charging station is close to the center of gravity and the layout is reasonable.

关键词： charging station electric vehicle(EV) improved random drift particle swarm optimization(IRDPSO) optimal planning

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GRAPH SPARSIFICATION BY UNIVERSAL GREEDY ALGORITHMS

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Journal of Computational Mathematics 2023年第4期41卷 741-770页

作者： Ming-Jun Lai jiaxin Xie Zhiqiang Xu Department of Mathematics University of GeorgiaAthensGA 30602USA LMIB of the Ministry of Education School of Mathematical SciencesBeihang UniversityBeijing 100191China LSEC Inst.Comp.Math.Academy of Mathematics and System ScienceChinese Academy of SciencesBeijing 100091China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

Graph sparsification is to approximate an arbitrary graph by a sparse graph and is useful in many applications,such as simplification of social networks,least squares problems,and numerical solution of symmetric positive definite linear systems.In this paper,inspired by the well-known sparse signal recovery algorithm called orthogonal matching pursuit(OMP),we introduce a deterministic,greedy edge selection algorithm,which is called the universal greedy approach(UGA)for the graph sparsification problem.For a general spectral sparsification problem,e.g.,the positive subset selection problem from a set of m vectors in R n,we propose a nonnegative UGA algorithm which needs O(mn^(2)+n^(3)/ϵ^(2))time to find a 1+ϵ/β/1-ϵ/β-spectral sparsifier with positive coefficients with sparsity at most[n/ϵ^(2)],where β is the ratio between the smallest length and largest length of the vectors.The convergence of the nonnegative UGA algorithm is established.For the graph sparsification problem,another UGA algorithm is proposed which can output a 1+O(ϵ)/1-O(ϵ)-spectral sparsifier with[n/ϵ^(2)]edges in O(m+n^(2)/ϵ^(2))time from a graph with m edges and n vertices under some mild assumptions.This is a linear time algorithm in terms of the number of edges that the community of graph sparsification is looking for.The best result in the literature to the knowledge of the authors is the existence of a deterministic algorithm which is almost linear,i.e.O(m^(1+o(1)))for some o(1)=O((log log(m))^(2/3)/log^(1/3)(m)).Finally,extensive experimental results,including applications to graph clustering and least squares regression,show the effectiveness of proposed approaches.

关键词： Spectral sparsification Subset selection Greedy algorithms Graph clustering Linear sketching

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