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Silencing of Transposable Elements by piRNAs in Drosophila:An Evolutionary Perspective

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Genomics, Proteomics & Bioinformatics 2017年第3期15卷 164-176页

作者： Shiqi luo jian lu State Key Laboratory of Protein and Plant Gene Research Center for BioinformaticsCollege of Life Sciences and Peking-Tsinghua Center for Life SciencesPeking University Beijing Advanced Innovation Center for Food Nutrition and Human Health College of Food Science and Nutritional EngineeringChina Agricultural University

Transposable elements （TEs） are DNA sequences that can move within the genome. TEs have greatly shaped the genomes, transcriptomes, and proteomes of the host organisms through a variety of mechanisms. However, TEs generally disrupt genes and destabilize the host genomes, which substantially reduce fitness of the host organisms. Understanding the genomic distribution and evolutionary dynamics of TEs will greatly deepen our understanding of the TE-mediated bio- logical processes. Most TE insertions are highly polymorphic in Drosophila melanogaster, providing us a good system to investigate the evolution of TEs at the population level. Decades of theoretical and experimental studies have well established ＂transposition-selection＂ population genetics model, which assumes that the equilibrium between TE replication and purifying selection determines the copy number of TEs in the genome. In the last decade, P-element-induced wimpy testis （PIW1）- interacting RNAs （piRNAs） were demonstrated to be master repressors of TE activities in Droso- phila, The discovery of piRNAs revolutionized our understanding of TE repression, because it reveals that the host organisms have evolved an adaptive mechanism to defend against TE invasion. Tremendous progress has been made to understand the molecular mechanisms by which piRNAs repress active TEs, although many details in this process remain to be further explored. The inter- action between piRNAs and TEs well explains the molecular mechanisms underlying hybrid dysge- nesis for the IoR and P-M systems in Drosophila, which have puzzled evolutionary biologists for decades. The piRNA repression pathway provides us an unparalleled system to study the co-evolutionary process between parasites and host organisms.

关键词： Transposable element piRNA Hybrid dysgenesis Evolution Drosophila

Current research on electrospinning of silk fibroin and its blends with natural and synthetic biodegradable polymers

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Frontiers of Materials Science 2013年第2期7卷 129-142页

作者： jian-Guang ZHANG Xiu-mei MO Biomaterials and Tissue Engineering Lab College of Chemistry Chemical Engineering & Biotechnology Donghua University Shanghai 201620 China

Silk fibroin （SF） is a kind of natural polymers with a great potential in biomedical application. Due to its good biocompatibility, biodegradability and minimal inflammatory reaction, SF is an excellent candidate for generating tissue engineering scaffolds. Electrospinning is a simple and effective method to fabricate nanofibers, which has several amazing characteristics such as very large surface area to volume ratio, flexibility in surface functionalities, and superior mechanical performance. The electro- spun nanofibers from SF and its blends have been used for varied tissue engineering. This paper will give a brief review about the structure, properties and applications of SF and blend nanofibers via electrospinning.

关键词： electrospinning nanofiber silk fibroin (SF) biodegradable polymer

Mechanocaloric materials for solid-state cooling

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Science Bulletin 2015年第19期60卷 1638-1643页

作者： Binfeng lu jian Liu Key Laboratory of Magnetic Materials and Devices Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences

This article reviews the up-to-date progress in mechanocaloric effect and materials near ambient temperature. For elastocaloric materials, we focus on directly measured temperature change and its entropy origin in nonmagnetic and magnetic shape memory alloys. In terms of barocaloric materials, change in magnetic state, volume and shift of transition temperature due to hydrostatic pressure are systematically compared. We propose advantages and challenges of elastocaloric materials for solidstate cooling. Strategies to enhance elastocaloric and mechanical stability under long-term mechanical cycles are presented. Finally, we conclude with an outlook on the prospect of elastocaloric cooling application.

关键词： Elastocaloric effect Barocaloric effect Shape memory alloy Entropy

Changes in the Vascular Cylinder of Wild Soybean Roots Under Alkaline Stress

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Journal of Integrative Agriculture 2014年第10期13卷 2164-2169页

作者： NIU lu lu Jing-mei WU Dong-mei LI Yan GAO Ting-ting School of Life Sciences Northeast Normal University Qinghai Key Laboratory of Tibetan Medicine Pharmacology and Safety Evaluation Northwest Institute of Plateau BiologyChinese Academy of Sciences

Changes in the vascular cylinder of wild soybean （Glycine soja Sieb. et Zucc） roots under alkaline stress were investigated in an experiment that applied 90 mmol L1 alkaline stress for 10 d at the five-trifoliate plant growth stage in Huinan County, Jilin Province, China. Root samples were collected and paraffin-cut sections were made, and the root structure was observed under an optical microscope. There were significant changes in the vascular cylinder of G. soja roots under alkaline stress. Root diameter was reduced and the vascular cylinder changed from tetrarch to triarch pattern. Alkaline stress resulted in reduced, diameters of root vessels, and a large amount of residual, alkaline solution was stained cyaneous in vessels. The paratracheal parenchymatous cells of the vessels were large and there was little secondary xylem. Thus, alkaline stress caused structural changes in the vascular cylinder of G. soja.

关键词： Glycine soja Sieb. et Zucc alkaline stress anatomical structure tetrarch condition of vascular cylinder triarchcondition of vascular cylinder

Global patterns of fern species diversity:An evaluation of fern data in GBIF

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Plant Diversity 2022年第2期44卷 135-140页

作者： Hong Qian jian Zhang mei-Chen jiang Research and Collections Center Illinois State Museum1011 East Ash StreetSpringfieldIL 62703USA Zhejiang Tiantong Forest Ecosystem National Observation and Research Station School of Ecological and Environmental SciencesEast China Normal University200241 ShanghaiChina

Despite that several studies have shown that data derived from species lists generated from distribution occurrence records in the Global Biodiversity Information Facility(GBIF)are not appropriate for those ecological and biogeographic studies that require high sampling completeness,because species lists derived from GBIF are generally very incomplete,Suissa et al.(2021)generated fern species lists based on data with GBIF for 100 km×100 km grid cells across the world,and used the data to determine fern diversity hotspots and species richness-climate *** conduct an evaluation on the completeness of fern species lists derived from GBIF at the grid-cell scale and at a larger spatial scale,and determine whether fern data derived from GBIF are appropriate for studies on the relations of species composition and richness with climatic *** show that species sampling completeness of GBIF is low(lude that fern species lists derived from GBIF are generally very incomplete across a wide range of spatial scales,and are not appropriate for studies that require data derived from species lists in high *** present a map showing global patterns of fern species diversity based on complete or nearly complete regional fern species lists.

关键词： Climate Data bias Fern GBIF Species diversity Species list

Energy-Efficient Optimal Guaranteed Cost Intermittent-Switch Control of a Direct Expansion Air Conditioning System

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IEEE/CAA Journal of Automatica Sinica 2021年第11期8卷 1852-1866页

作者： Jun mei Zhenyu lu Junhao Hu Yuling Fan School of Mathematics and Statistics South-Central University for NationalitiesWuhan 430074China School of Electronic and Information Engineering Nanjing University of Information Science and TechnologyNanjing 210044China College of Informatics Huazhong Agricultural UniversityWuhan 430072China

To improve the energy efficiency of a direct expansion air conditioning(DX A/C) system while guaranteeing occupancy comfort, a hierarchical controller for a DX A/C system with uncertain parameters is proposed. The control strategy consists of an open loop optimization controller and a closed-loop guaranteed cost periodically intermittent-switch controller(GCPISC). The error dynamics system of the closed-loop control is modelled based on the GCPISC principle. The difference,compared to the previous DX A/C system control methods, is that the controller designed in this paper performs control at discrete times. For the ease of designing the controller, a series of matrix inequalities are derived to be the sufficient conditions of the lower-layer closed-loop GCPISC controller. In this way, the DX A/C system output is derived to follow the optimal references obtained through the upper-layer open loop controller in exponential time, and the energy efficiency of the system is improved. Moreover, a static optimization problem is addressed for obtaining an optimal GCPISC law to ensure a minimum upper bound on the DX A/C system performance considering energy efficiency and output tracking error. The advantages of the designed hierarchical controller for a DX A/C system with uncertain parameters are demonstrated through some simulation results.

关键词： Energy efficiency hierarchical control open loop optimal control optimal guaranteed cost periodically intermittent-switch control

Determination of Sex Hormones in Antler Velvet by High Performance Liquid Chromatography Tandem Mass Spectrometry

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Chemical Research in Chinese Universities 2012年第2期28卷 191-194页

作者： lu Chun-mei WANG Ming-tai MU Jun BAI Yu-ping DU jian-shi ZHANG Han-qi WANG jian-wei College of Chemistry Jilin UniversityChangchun 130012P.R.China China-Japan Union Hospital of Jilin University Changchun 130021P.R.China Jilin Entry-exit Inspection and Quarantine Bureau Changehun 130061R R.China China FAW Group Corporation R&D Center Changchun 130011P.R.China Institute of Applied Chemistry Chinese Academy of SciencesChangchun 130022P.R.China

Eighteen sex hormones in antler velvet were determined by high performance liquid chromatography tandem mass *** solid phase extraction was applied to eliminating the matrix *** experimental conditions were examined and *** the optimal conditions,the proposed method provides the good linearities and determination limits（0.2―1.0 μg/kg） of the analytes *** recoveries ranging from 72.3% to 149.5% were obtained for the target analytes at two concentration *** method was applied to the determination of eighteen sex hormones in different kinds of antler velvet samples and the obtained results are *** results indicate that the proposed method is suitable for the determination of sex hormones in antler velvet samples.

关键词： Antler velvet Liquid chromatography tandem mass spectrometry Sex hormone Solid-phase extraction

Microstructure and mechanical properties of BFe10 cupronickel alloy tubes fabricated by a horizontal continuous casting with heating-cooling combined mold technology

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International Journal of Minerals,Metallurgy and Materials 2012年第4期19卷 339-347页

作者： Jun mei Xin-hua Liu jian-xin Xie Key Laboratory for Advanced Materials Processing (Ministry of Education) University of Science and Technology Beijing Beijing 100083 China Institute for Advanced Materials and Technology University of Science and Technology Beijing Beijing 100083 China

A new horizontal continuous casting method with heating-cooling combined mold （HCCM） technology was explored for fabri- cating high-quality thin-wall cupronickel alloy tubes used for heat exchange pipes. The microstructure and mechanical properties of BFe 10 cupronickel alloy tubes fabricated by HCCM and traditional continuous casting （cooling mold casting） were comparatively investigated. The results show that the tube fabricated by HCCM has smooth internal and external surfaces without any defects, and its internal and external surface roughnesses are 0.64 μm and 0.85 μm, respectively. The tube could be used for subsequent cold processing without other treatments such as surface planning, milling and acid-washing. This indicates that HCCM can effectively reduce the process flow and improve the pro- duction efficiency of a BFel0 cupronickel alloy tube. The tube has columnar grains along its axial direction with a major casting texture of {012}〈 621 〉. Compared with cooling mold casting （6 = 36.5%）, HCCM can improve elongation （3 = 46.3%） by 10% with a slight loss of strength, which indicates that HCCM remarkably improves the cold extension performance of a BFe 10 cupronickel alloy tube.

关键词： cupronickel alloys thin-wall tubes continuous casting microstructure mechanical properties

Segmental Kinematic Coupling of the Human Spinal Column during Locomotion

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Journal of Bionic Engineering 2008年第4期5卷 328-334页

作者： Guo-ru Zhao Lei Ren lu-quan Ren John R. Hutchinson Li-mei Tian jian S. Dai Key Laboratory for Terrain-Machine Bionics Engineering （Ministry of Education China） Jilin University Changchun 130022 P. R. China School of Physical Science and Engineering King＇s College of London University of London London WC2R 2LS UK Structure and Motion Laboratory Department of Veterinary Basic Sciences The Royal Veterinary College University of London Hertfordshire AL9 7TA UK

As one of the most important daily motor activities, human locomotion has been investigated intensively in recent decades. The locomotor functions and mechanics of human lower limbs have become relatively well understood. However, so far our understanding of the motions and functional contributions of the human spine during locomotion is still very poor and simultaneous in-vivo limb and spinal column motion data are scarce. The objective of this study is to investigate the delicate in-vivo kinematic coupling between different functional regions of the human spinal column during locomotion as a stepping stone to explore the locomotor function of the human spine complex. A novel infrared reflective marker cluster system was constrncted using stereophotogrammetry techniques to record the 3D in-vivo geometric shape of the spinal column and the segmental position and orientation of each functional spinal region simultaneously. Gait measurements of normal walking were conducted. The preliminary results show that the spinal column shape changes periodically in the frontal plane during locomotion. The segmental motions of different spinal functional regions appear to be strongly coupled, indicating some synergistic strategy may be employed by the human spinal column to facilitate locomotion. In contrast to traditional medical imaging-based methods, the proposed technique can be used to investigate the dynamic characteristics of the spinal column, hence providing more insight into the functional biomechanics of the human spine.

关键词： biomechanics spinal cofumn human locomotion in-vivo segmental kinematics motion analysis stereophotogrammetry kinematic coupling