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Long-Chain Alkenones in the South Yellow Sea Sediments and Their Indicative Significance for Haptophytes Species

Journal of Ocean University of China 2024年第5期23卷 1287-1296页

作者： xu yakun YANG Xinxin XIAO Rui XING Lei Key Laboratory of Marine Chemistry Theory and Engineering Technology Ministry of Education Ocean University of China Laboratory of Marine Ecology and Environment Science Qingdao National Laboratory for Marine Science and Technology

Long-chain alkenones（LCAs） have been widely used as important biomarkers in palaeoceanographic ***,the commonly used LCAs proxies are mainly based on C37alkenones,and it is still lack of the studies about the distribution and indications of LCAs with different chain lengths other than ***,the composition and distribution of LCAs were analyzed in surface sediments from the southern Yellow Sea（SYS） and a sedimentary core（A02-C） from the central Yellow Sea（YS）mud *** results showed that C37,C38and C39alkenones were the major LCAs in surface sediments of the SYS,and the relative contents of C38:2Et,C37:2Me,C37:3Me,C38:2Me,C38:3Et,C38:3Me,C39:2Et and C39:3Et were 18.3%-59.8%,22.6%-41.2%,7.4%-23.0%,6.6%-15.4%,3.8%-13.3 %,3.6%-8.7%,2.8%-6.0% and 0.7%-3.0%,*** the relationships of U38MeK-U38EtKand U37K'-U38EtKindicate that LCAs are mainly derived from Emiliania huxleyi（***）.High ratios of total C37alkenones to total C38alkenones(K37/K38)（1-1.2） were found in the central SYS,corresponding to the relatively high abundance of ***;while low ratios of K37/K38（0.7-0.9） were observed at nearshore area of the SYS where Gephyrocapsa oceanica（***） has relatively high *** spatial distribution of K37/K38ratio is also consistent with that of coccolithophores nannofossil in the *** addition,K37/K38ratio in core A02-C varied from 0.7 to 1.1 with a gradual decreasing trend during the past 5.5 *** suggests that the relative abundance of *** decreased gradually,caused by the changes in the Yellow Sea Warm Current（YSWC） and the East Asian Winter Monsoon（EAWM） during this period.

关键词： alkenones sediment southern Yellow Sea Yellow Sea Warm Current

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基于全寿命效费比的地铁上盖隔震(振)结构优化设计方法

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地震工程与工程振动 2024年第4期44卷 1-14页

作者：王振李祚华许亚昆滕军何春凯哈尔滨工业大学(深圳)土木与环境工程学院广东深圳518055 深圳中建院建筑科技有限公司广东深圳518063

隔震(振)技术是提升地铁上盖建筑抗震性能和舒适度的有效措施,优化此类结构设计方法具有现实意义和紧迫性。提出了适用于地铁上盖隔震(振)结构的全寿命效费比评估模型;采用基于结构响应的全寿命评估方法,研究了周期比、质量比、隔震层... 详细信息

隔震(振)技术是提升地铁上盖建筑抗震性能和舒适度的有效措施,优化此类结构设计方法具有现实意义和紧迫性。提出了适用于地铁上盖隔震(振)结构的全寿命效费比评估模型;采用基于结构响应的全寿命评估方法,研究了周期比、质量比、隔震层刚度及阻尼等关键结构参数对地铁上盖隔震(振)结构效益的影响;基于遗传算法提出了地铁上盖隔震(振)结构优化设计方法。研究结果表明:增加隔震层后结构地震损失主要集中于下部结构,上、下部结构质量比越大地震损失越小;上下部结构周期比越大,地震损失越小;隔振层刚度与隔振效益呈正相关;采用提出的优化算法对原型结构优化后,地震损失费用可减小30%,竖向振动加速度级可减小2 dB,验证了该方法的可行性。

关键词：地铁上盖隔震(振)结构全寿命费用效费比优化设计

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Is Minimizing Flow Completion Time the Optimal Way in Meeting Flow's Deadline in Datacenter Networks

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China Communications 2016年第S1期13卷 6-15页

作者： xu yakun LUO Hongbin REN Fei National Engineering Laboratory for Next Generation Internet Technologies School of Electronic and Information Engineering Beijing Jiaotong University

In modern datacenters, the most common method to solve the network latency problem is to minimize flow completion time during the transmission process. Following the soft real-time nature, the optimization of transport latency is relaxed to meet a flow's deadline in deadline-sensitive services. However, none of existing deadline-sensitive protocols consider deadline as a constraint condition of *** can only simplify the objective of meeting a flow's deadline as a deadline-aware mechanism by assigning a higher priority for tight-deadline constrained flows to finish the transmission as soon as possible, which results in an unsatisfactory effect in the condition of high fan-in degree. It drives us to take a step back and rethink whether minimizing flow completion time is the optimal way in meeting flow's deadline. In this paper, we focus on the design of a soft real-time transport protocol with deadline constraint in datacenters and present a flow-based deadline scheduling scheme for datacenter networks(FBDS).FBDS makes the unilateral deadline-aware flow transmission with priority transform into a compound centralized single-machine deadlinebased flow scheduling decision. In addition, FBDS blocks the flow sets and postpones some flows with extra time until their deadlines to make room for the new arriving flows in order to improve the deadline meeting rate. Our simulation resultson flow completion time and deadline meeting rate reveal the potential of FBDS in terms of a considerable deadline-sensitive transport protocol for deadline-sensitive interactive services.

关键词： datacenter networks deadline preemptive scheduling flow completion time

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基于1D/3D耦合仿真的某大功率重型货车冷却系统性能研究

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汽车工程 2024年第6期46卷 1125-1135页

作者：程浩杰马彦达徐亚坤吴延巽董丽萍于振华张艺伦中国重汽集团汽车研究总院济南250000 中国重汽集团济南250000 中汽研(天津)汽车工程研究院天津300000

随着经济的快速发展,人们对商用车的功率需求越来越高,大功率意味着更高的散热负荷,这对发动机冷却系统的匹配及系统的空间布置提出了更高的挑战。针对装配600马力发动机的某重型商用车,采用1D/3D耦合仿真的手段建立整车热流场模型与发... 详细信息

随着经济的快速发展,人们对商用车的功率需求越来越高,大功率意味着更高的散热负荷,这对发动机冷却系统的匹配及系统的空间布置提出了更高的挑战。针对装配600马力发动机的某重型商用车,采用1D/3D耦合仿真的手段建立整车热流场模型与发动机冷却系统一维模型,研究了护风罩、导流板对散热器进风流量与进风平均温度的影响;并根据发动机热平衡试验数据,完成了冷却系统的匹配计算,同时进行了整车热平衡试验验证。结果表明:与单层护风罩相比,C型护风罩所引起的湍动能较小,因而可以提供更大的风量;当水泵速比由2.2降至为1.8时,转矩点和功率点出水温度分别为99.2和96.2℃,可满足冷却的需求,同时也降低了水泵的能耗,此外整车环境舱试验也验证了仿真模型的准确性,在大转矩工况下C型护风罩可以有效降低冷却系统的水温。

关键词：发动机热平衡 C型护风罩冷却系统导流板水泵能耗

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选区激光熔化TiC/AlMgSc复合材料组织及性能研究

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激光与光电子学进展 2024年第9期61卷 382-390页

作者：丁惟云司福贵夏长庚孙德志徐亚坤徐英翠程浩杰王孟志季伟中国重型汽车集团有限公司山东济南250101 中国重型汽车集团有限公司汽车研究总院山东济南250101

基于选区激光熔化(SLM)成形工艺制备了亚μm TiC颗粒增强AlMgSc复合材料,研究了TiC/AlMgSc复合材料的物相组成、显微组织和力学性能。研究结果表明:采用优化后的SLM成形工艺参数获得了高致密度(99.73%)的TiC/AlMgSc复合材料;SLM成形中Ti... 详细信息

基于选区激光熔化(SLM)成形工艺制备了亚μm TiC颗粒增强AlMgSc复合材料,研究了TiC/AlMgSc复合材料的物相组成、显微组织和力学性能。研究结果表明:采用优化后的SLM成形工艺参数获得了高致密度(99.73%)的TiC/AlMgSc复合材料;SLM成形中TiC颗粒与AlMgSc基体之间没有发生反应,TiC颗粒提供了高密度的有效形核点,促使复合材料组织向等轴晶转变,晶粒发生细化,并且减弱了织构强度;添加TiC颗粒后,复合材料抗拉强度提升了9.9%,达到了611 MPa,延伸率下降为10.02%;材料的断裂机制主要为韧脆混合断裂,在断口表面处留存着尺寸为3~8μm的TiC团簇颗粒,并黏附在铝基体中。

关键词：激光技术选区激光熔化铝基复合材料微观组织拉伸性能

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Expanding the Scope of Multivariate Regression Approaches in Cross-Omics Research

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Engineering 2021年第12期7卷 1725-1731页

作者： Xiaoxi Hu Yue Ma yakun xu Peiyao Zhao Jun Wang CAS Key Laboratory of Pathogenic Microbiology and Immunology Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China Bloomberg School of Public Health Johns Hopkins UniversityBaltimoreMD 21205USA University of Chinese Academy of Sciences Beijing 100049China Department of Biostatistics University of MichiganAnn ArborMI 48109-2029USA

Recent technological advancements and developments have led to a dramatic increase in the amount of high-dimensional data and thus have increased the demand for proper and efficient multivariate regression *** traditional multivariate approaches such as principal component analysis have been used broadly in various research areas,including investment analysis,image identification,and population genetic structure ***,these common approaches have the limitations of ignoring the correlations between responses and a low variable selection ***,in this article,we introduce the reduced rank regression method and its extensions,sparse reduced rank regression and subspace assisted regression with row sparsity,which hold potential to meet the above demands and thus improve the interpretability of regression *** conducted a simulation study to evaluate their performance and compared them with several other variable selection *** different application scenarios,we also provide selection suggestions based on predictive ability and variable selection ***,to demonstrate the practical value of these methods in the field of microbiome research,we applied our chosen method to real population-level microbiome data,the results of which validated our *** method extensions provide valuable guidelines for future omics research,especially with respect to multivariate regression,and could pave the way for novel discoveries in microbiome and related research fields.

关键词： Multivariate regression methods Reduced rank regression Sparsity Dimensionality reduction Variable selection

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Of genes and microbes： solving the intricacies in host genomes

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Protein & Cell 2018年第5期9卷 446-461页

作者： Jun Wang Liang Chen Na Zhao Xizhan xu yakun xu Baoli Zhu CAS Key Laboratory of Pathogenic Microbiology and Immunology Institute of Microbiology Chinese Academy of Science Beijing 100101 China University of Chinese Academy of Sciences Beijing 100049 China Collaborative Innovation Centre for Diagnosis and Treatment of Infectious Diseases First Affiliated Hospital School of Medicine Zhejiang University Hangzhou 310058 China

Microbiome research is a quickly developing field in biomedical research, and we have witnessed its poten- tial in understanding the physiology, metabolism and immunology, its critical role in understanding the health and disease of the host, and its vast capacity in disease prediction, intervention and treatment. However, many of the fundamental questions still need to be addressed, including the shaping forces of microbial diversity between individuals and across time. Microbiome research falls into the classical nature vs. nurture sce- nario, such that host genetics shape part of the micro- biome, while environmental influences change the original course of microbiome development. In this review, we focus on the nature, i.e., the genetic part of the equation, and summarize the recent efforts in understanding which parts of the genome, especially the human and mouse genome, play important roles in determining the composition and functions of microbial communities, primarily in the gut but also on the skin. We aim to present an overview of different approaches in studying the intricate relationships between host genetic variations and microbes, its underlying philos- ophy and methodology, and we aim to highlight a few key discoveries along this exploration, as well as current pitfalls. More evidence and results will surely appear in upcoming studies, and the accumulating knowledge will lead to a deeper understanding of what we could finally term a ＂hologenome＂, that is, the orga- nized, closely interacting genome of the host and the microbiome.

关键词： gut microbiota host genetics quantitativegenetics gene-microbiome association

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紫外辐照及甲基磺酸乙酯诱变对马铃薯早熟品种淀粉含量和产量性状的影响

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山西农业科学 2024年第5期52卷 75-84页

作者：徐宁许亚坤张洪亮张荣华刘冬雪王维峰黑龙江省农垦科学院经济作物研究所黑龙江哈尔滨150030

针对黑龙江省现有马铃薯早熟品种淀粉含量较低的问题,通过紫外辐照和甲基磺酸乙酯浸泡2种方式,对东农303和中龙薯1号的组培苗进行处理,经过3 a的种植、调查和数据采集,确定诱变方式对不同品种马铃薯变异程度和诱变方向的影响,以改良获... 详细信息

针对黑龙江省现有马铃薯早熟品种淀粉含量较低的问题,通过紫外辐照和甲基磺酸乙酯浸泡2种方式,对东农303和中龙薯1号的组培苗进行处理,经过3 a的种植、调查和数据采集,确定诱变方式对不同品种马铃薯变异程度和诱变方向的影响,以改良获得早熟且高淀粉含量的马铃薯品种。结果表明,诱变后,整体变化表现为无变化>抑制>促进,其中东农303更易发生变异,紫外辐照的诱变效果更佳。在组培苗阶段,多数处理显示为抑制作用;在原原种阶段,紫外辐照有利于东农303产量的提升和中龙薯1号淀粉含量的增加;在原种阶段,甲基磺酸乙酯浸泡对东农303的商品性有提升作用,而2种诱变方式对中龙薯1号的产量和结薯数量均有明显抑制作用,紫外辐照的影响更为显著。在紫外辐照处理中,2个品种均发现了1个淀粉含量明显提升的单株,2个单株的发现将有利于黑龙江省不同熟期品种的搭配种植,减少完全依赖晚熟品种所带来的种植风险,并可有效提升产业效益。

关键词：马铃薯淀粉含量紫外辐照甲基磺酸乙酯浸泡产量

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Alterations of the oral and gut mycobiome and cytokines during long-term follow-up of COVID-19 convalescents

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Signal Transduction and Targeted Therapy 2023年第5期8卷 2061-2063页

作者： Zhigang Ren Shanshuo Liu Qiong Wang Benchen Rao Zhaohai Zeng yakun xu Haiyu Wang Hong Luo Jianjun Gou Zujiang Yu Department of Infectious Diseases the First Affiliated Hospital of Zhengzhou UniversityZhengzhou450052China Health Management Center the First Affiliated Hospital of Zhengzhou UniversityZhengzhou450052China Department of Infectious Diseases Guangshan County People’s HospitalGuangshan CountyXinyang465450HenanChina

Dear Editor,A large number of COVID-19 patients experience body-specific conditions such as fatigue,sleep disturbances,anxiety,depression,and dyspnea after the disease has subsided,which is called“long COVID-19”.1 Studies have confirmed reduced microbial diversity,enrichment of opportunistic pathogens and depletion of beneficial symbiotic bacteria in patients with COVID-19.2,3 Long-term dysregulation of the microbiota has also been observed in recovered patients.4 Nevertheless,long-term fungal microbiota follow-up was still blank.

关键词： patients cytokines sided

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Reconstruction and Dynamics of the Human Intestinal Microbiome Observed In Situ

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Engineering 2022年第8期8卷 89-101页

作者： Xiaolin Liu Min Dai Yue Ma Na Zhao Ziyu Wang Ying Yu yakun xu Huijie Zhang Liyuan Xiang He Tian Guanghou Shui Faming Zhang Jun Wang CAS Key Laboratory of Pathogenic Microbiology and Immunology Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Medical Center for Digestive Diseases the Second Affiliated Hospital of Nanjing Medical UniversityNanjing 210011China Clinical Trial Center Office the Second Affiliated Hospital of Nanjing Medical UniversityNanjing 210011China State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China Key Lab of Holistic Integrative Enterology Nanjing Medical UniversityNanjing 210011China

The human gut microbiome has primarily been studied through the use of fecal samples,a practice that has generated vital knowledge on the composition and functional capacities of gastrointestinal microbial ***,this reliance on fecal materials limits the investigation of microbial dynamics in other locations along the gastrointestinal tract(in situ),and the infrequent availability of fecal samples prevents analysis at finer temporal scales(e.g.,hours).In our study,we utilized colonic transendoscopic enteral tubing,a technology originally developed for fecal microbiota transplantation,to sample the ileocecal microbiome twice daily;metagenomic and metatranscriptomic analyses were then conducted on these samples.A total of 43 ileocecal and 28 urine and fecal samples were collected from five healthy *** ileocecal and fecal microbiomes,as profiled in the five volunteers,were found to be similar in metagenomic profiling,yet their active genes(metatranscriptome)were found to be highly *** microbiomes were perturbed after laxative exposure;over time,they exhibited reduced dissimilarity to their pre-treatment state,thereby demonstrating resilience as an innate property of the gut microbiome,although they did not fully recover within our observation time *** of the ileocecal microbiome during the day and at night revealed the existence of diurnal rhythms in a series of bacterial species and functional pathways,particularly those related to short-chain fatty acid production,such as Propionibacterium acnes and coenzyme A biosynthesis Ⅱ.Autocorrelation analysis and fluctuations decomposition further indicated the significant periodicity of the diurnal *** profiling in the fecal and urine samples mirrored the perturbance and recovery in the gut microbiome,indicating the crucial contribution of the gut microbiome to many key metabolites involved in host *** study provides novel insights into the human gut

关键词： Diurnal rhythm Reconstruction Metagenome Metatranscriptome Metabolome Transendoscopic enteral tubing

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