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INVARIANCE AND STABILITY OF THE PROFILE EQUATIONS OF GEOmETRIC OPTICS

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Acta mathematica Scientia 2011年第6期31卷 2141-2158页

作者： guy mtivier Jeffrey Rauch Institut de mathmatiques de Bordeaux Universit de Bordeaux Department of mathematics University of Michigan

The profile equations of geometric optics are described in a form invariant under the natural transformations of first order systems of partial differential equations. This allows us to prove that various strategies for computing profile equations are equivalent. We prove that if L generates an evolution on L2 the same is true of the profile equations. We prove that the characteristic polynomial of the profile equations is the localization of the characteristic polynomial of the background operator at （y, dφ（y）） where φ is the background phase. We prove that the propagation cones of the profile equations are subsets of the propagation cones of the background operator.

关键词： geometric optics profile equation localisation vector bundles propagation cones

Spatial and Temporal Variability of Farm Size in China in Context of Rapid Urbanization

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Chinese Geographical Science 2013年第5期23卷 607-619页

作者： TAN minghong guy m ROBINSON LI Xiubin XIN Liangjie Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Centre for Rural Health&Community Development University of South Australia

During the last 30 years, China has witnessed rapid economic growth and dramatic urbanization, with about 1.2 x 107 rural people migrating annually into urban areas. meanwhile, especially since 1995, the rural population has been declining, which is closely linked to land circulation and the increase in farm size in many villages. Increasing scale of farming operations is often regarded as a key to avoiding the abandonment of farmland and to increasing the income of rural farmers. However, until now, there has been little research on the spatial and temporal variability of farm size at the national level in China. Using data from the national agricultural cen- sus and rural household surveys, this study examines the characteristics of land use circulation and the consequent changes in the area of farmland per household. The results show that： 1） 12.2% of rural households were involved in land circulation at the national level. The highest amounts of land circulation have occurred in those provinces where the farmland per capita is more than 0.2 ha or less than 0.1 ha; 2） over 80% of households operate less than 0.6 ha of farmland; 3） the proportion of mid-sized farms （between 0.2 ha and 0.6 ha per household） has decreased while the smallest and the largest farms have increased. This bears some similarity with the phenomenon known as the ＇disappearing middle＇, referring to the changes in farm size. This study establishes a framework for interpreting the factors affecting the changes in farm size in China, which include two promoting factors （urbanization and agriculture） and four hindering fac- tors （agricultual land system, household registration, stable clan system, and farmland loss）.

关键词： farm size land circulation urbanization China

Global sustainable agriculture and land management systems

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Geography and Sustainability 2024年第4期5卷 637-646页

作者： guy m.Robinson Department of Geography Environment and PopulationSchool of Social SciencesUniversity of AdelaideAdelaideSouth Australia 5005Australia Laboratory of Interdisciplinary Spatial Analysis(LISA) Department of Land EconomyUniversity of Cambridge19 Silver StreetCambridge CB39EPUnited Kingdom

The paper introduces a Special Issue based on presentations to the Agricultural Geography and Land Engineering(AGLE)Commission sessions of the International Geographical Union(IGU)at the IGU’s Congress in Paris in *** sessions contrasted different approaches towards attaining greater sustainability in agricultural production to satisfy the need to feed the ever-increasing human population,currently expected to reach close to ten billion by *** considering the multi-faceted problem of defining sustainable agriculture,this introduction systematically outlines broad strategies to attain the varied outcomes desired by agricultural *** a contrast between ecocentric and technocentric approaches provides opportunities to synthesize recent literature addressing the pros and cons of these two broad *** of the ecological and socio-cultural benefits accruing from the ecocentric has long been championed by proponents of a wide range of environmentally friendly farming systems,including organic farming,climate-smart agriculture,agroforestry,and *** technocentric lies at the heart of so-called Agriculture 4.0,in which innovations such as precision farming,digital technology,and genetic modification are applied to increase production per unit *** potential for technology to‘solve’the world’s food crisis is supported by those who argue that ecocentric approaches alone cannot meet the rising demand for ***,questions remain about the sustainability of new technology-based methods,so a strong and ongoing debate continues regarding how to attain greater sustainability alongside increasing agricultural *** debate is exemplified in the contributions to the Special Issue outlined herewith.

关键词： Sustainability Agriculture Sustainable development goals Food security

Ferritin acts as a target site for the snowdrop lectin （GNA） in the midgut of the cotton leafworm Spodoptera littoralis

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Insect Science 2008年第6期15卷 513-519页

作者： Amin Sadeghi guy Smagghe Paul Proost Els J.m. Van Damme Laboratory of Agrozoology Department of Crop Protection Laboratory of Biochemistry and Glycobiology Department of Molecular Biotechnology Faculty of Bioscience Engineering Ghent University Ghent Rega Institute Laboratory of Molecular Immunology Kathofieke Universiteit Leuven Minderbroedersstraat 10 B-3000 Leuven Belgium

The snowdrop lectin GNA （Galanthus nivalis agglutinin） has been shown to possess insecticidal activity to a range of economically important insect pests. However, the precise mechanism of insecticidal action of GNA against insects remains unknown. In this investigation, we attempted to purify and identify receptor（s） responsible for binding of GNA in the larval midgut of a major lepidopteran pest （the cotton leafworm, Spodoptera littoralis） to better understand its mode of action. Therefore, cytoplasmic as well as membrane proteins from 800 larval midguts were chromatographed on a column with immobilized GNA. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the proteins eluted from the GNA column followed by sequencing of the GNA-binding proteins and BLAST analyses revealed that the N-terminal sequences of a 24 kDa polypeptide purified from the cytoplasmic and membrane protein fraction revealed sequence similarity to sequences encoding heavy chain homologs of ferritin from manduca sexta （76% sequence identity）, Calpodes ethlius （80% sequence identity） and Bombyx mori （61% sequence identity）. Furthermore, the N-terminal sequence of a 31 kDa polypeptide from the membrane protein fraction showed sequence similarity to a light chain homolog of ferritin from manduca sexta （88% sequence identity）.

关键词： ferritin Galanthus nivalis agglutinin GNA Lepidoptera midgut receptors Spodoptera littoralis

mechanical microenvironments of living cells: a critical frontier in mechanobiology

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Acta mechanica Sinica 2019年第2期35卷 265-269页

作者： Guoyou Huang Feng Xu guy m. Genin Tian Jian Lu The Key Laboratory of Biomedical Information Engineering of ministry of Education School of Life Science and Technology Xi’an Jiaotong University Xi’an 710049 China Bioinspired Engineering and Biomechanics Center (BEBC) Xi’an Jiaotong University Xi’an 710049 China Department of mechanical Engineering &materials Science Washington University in St. Louis St. Louis 63130 MO USA NSF Science and Technology Center for Engineering mechanobiology Washington University in St. Louis St. Louis 63130 MO USA State Key Laboratory of mechanics and Control of mechanical Structures Nanjing University of Aeronautics and Astronautics Nanjing 210016 China State Key Laboratory for Strength and Vibration of mechanical Structures Xi'an Jiaotong University Xi'an 710049 China

The fields of biomechanics and mechanobiology have long been predicated on the premise that mechanics governs cell behavior. However, over the past few years, a growing body of evidence has suggested that the mechanical environment very close to cells–the cell microenvironment–plays the most important role in determining what a cell feels and how it responds to tissue-level stimuli. To complicate matters further, cells can actively manipulate their microenvironments through pathways of recursive mechanobiological feedback. Harnessing this recursive behavior to understand and control cell physiology and pathophysiology is a critical frontier in the field of mechanobiology. Recent results suggest that the key to opening this scientific frontier to investigation and engineering application is understanding a different frontier: the physical frontier that cells face when probing their mechanical microenvironments.

关键词： mechanical microenvironments living cells mechanobiology

RNAi of the N-glycosylation-related genes confirms their importance in insect development and α-1,6-fucosyltransferase plays a role in the ecdysis event for the hemimetabolous pest insect Nilaparvata lugens

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Insect Science 2022年第1期29卷 91-99页

作者： Qun Yang Kristof De Schutter Pengyu Chen Els J.m.Van Damme guy Smagghe Laboratory of Agrozoology Department of Plants and CropsFaculty of Bioscience EngineeringGhent UniversityCoupure links 653Ghent9000Belgium Laboratory of Biochemistry and Glycobiology Department of BiotechnologyFaculty of Bioscience EngineeringGhent UniversityCoupure links 653Ghent9000Belgium

Recently N-glycosylation was found to be required for the postembryonic development and metamorphosis of the holometabolous beetle Tribolium castaneum. However, the role of N-glycosylation in the development of hemimetabolous insects is unknown. To further elucidate the role of N-glycosylation in the development of insects, a functional characterization of the N-glycosylation-related genes (NGRGs) was performed in a model insect for hemimetabolous development, namely the brown planthopper Nilaparvata lugens. In this project, we report the effects of RNAi-mediated silencing of 15 NGRGs on the postembryonic development of N. lugens. Two major observations were made. First, interruption of the early steps of N-glycan processing led to a lethal phenotype during the transition from nymph to adult as was observed in T. castaneum. Second, we report here on an essential function for the α-1,6-fucosyl transferase in the ecdysis event of N. lugens between nymphal instars, since gene-silencing by RNAi led to failure of ecdysis and subsequent mortality of the treated insect.

关键词： development glycosylation Nilaparvata lugens N-glycan postembryonic RNA interference

Binding of Orysata lectin induces an immune response in insect cells

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Insect Science 2022年第3期29卷 717-729页

作者： Pengyu Chen Kristof De Schutter Jarne Pauwels Kris Gevaert Els J.m.Van Damme guy Smagghe Faculty of Bioscience Engineering Department of Plants and CropsGhent UniversityGhentBelgium Faculty of Bioscience Engineering Department of BiotechnologyGhent UniversityGhentBelgium Faculty of medicine and Health Sciences Department of Biomolecular MedicineGhent UniversityGhentBelgium VIB Center for medical Biotechnology GhentBelgium

In mammals,plant lectinshave been shown to possess immunomodulatory properties,acting in both the innate and adaptive immune system to modulate the production of mediators of the immune response,ultimately improving host *** present,knowledge of immunomodulatory effects of plant lectins in insects is *** of insect cells with the Orysa sativa lectin,Orysata,was previously reported to induce cell aggregation,mimicking the immune process of *** this project we investigated the potential immunomodulatory effects of this mannose-binding lectin using Drosophila melanogaster S2 *** of the Orysata binding partners on the surface of S2 cells through a pull-down assay andproteomic analysis revealed 221 putative interactors,several of which were immunity-related *** qPCR analysis revealed the upregulation of Toll-and immune deficiency(ImD)-regulated antimicrobial peptides(Drs,mtk,AttA,and Dpt)and signal transducers(Rel and Hid)belonging to the ImD *** addition,the iron-binding protein Transferrin 3 was identified as a putative interactor for Orysata,and treatment of S2 cells with Orysata was shown to reduce the intracellular iron *** together,we believe these results offer a new perspective on the effects by which plant lectins influence insect cells and contribute to the study of their immunomodulatory properties.

关键词： cell culture immune response iron uptake Orysata plant lectin pull-down

Volumetric response of an ellipsoidal liquid inclusion: implications for cell mechanobiology

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Acta mechanica Sinica 2019年第2期35卷 338-342页

作者： Xin Chen Wei He Shaobao Liu moxiao Li guy m. Genin Feng Xu Tian Jian Lu State Key Laboratory for Strength and Vibration of mechanical Structures Xi'an Jiaotong University Xi'an 710049 China Bioinspired Engineering and Biomechanics Center (BEBC) Xi’an Jiaotong University Xi'an 710049 China State Key Laboratory of mechanics and Control of mechanical Structures Nanjing University of Aeronautics and Astronautics Nanjing 210016 China The Key Laboratory of Biomedical Information Engineering of ministry of Education Xi’an Jiaotong University Xi'an 710049 China U.S. National Science Foundation Science and Technology Center for Engineering mechanobiology Washington University St. Louis MO 63130 USA Nanjing Center for multifunctional Lightweight materials and Structures (mLmS) Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

Elastic composites containing liquid inclusions exist widely in nature and engineering fields. The volumetric response of liquid inclusions is important in many cases, such as an isolated cell embedded in an extracellular matrix and an oil pocket embedded within shale. In this study, we developed a model for describing the volumetric response of an ellipsoidal liquid inclusion. Specifically, we investigated the volumetric response of an ellipsoidal liquid inclusion embedded in a three-dimensional (3D) matrix through an analytical expression of the volumetric response. We performed parametric analysis and found that loading along the shortest axis can induce the most volume change, while loading along the longest axis can induce the least volume change. We also found that the volumetric response decreases with increasing Poisson ratio of the matrix. These results could be used to understand some cell behavior in a 3D matrix, for example, cell alignment under mechanical load.

关键词： Liquid inclusion Liquid compressibility Inclusion theory Solid-liquid interaction

Water balloon-induced orbital fracture in an aviator

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military medical Research 2020年第2期7卷 245-248页

作者： Timothy E.Holland David m.Smith guy N.Gibson Jared G.Brinkerhoff Flight and Operational medical Clinic 78th Medical Group655 Seventh StreetRobins Air Force BaseRobinsGA 31098USA Department of Radiology Ehrling Bergquist Clinic2501 Capehart RdOffutt AFBNEOffutt 68113-2160USA Flight and Operational medical Clinic 5th Medical Group194 Missilie AveMinot AFBNDMinot 58705USA

Background:Orbital fractures are common injuries found in facial *** etiologies of orbital fractures include motor vehicle collisions and *** report the case of a 32-year-old male who suffered an orbital fracture from a water ***,we describe the aeromedical complications that may result from this ***,we attempt to answer the question of when a patient may return to flying after sustaining such an injury through review of the *** presentation:A 32-year-old male pilot with the United States Air Force was at an outdoor event with his unit when he was struck with a water balloon launched from a sling shot into his left *** afterwards,he had an onset of subcutaneous emphysema and was escorted to a nearby Emergency *** tomography identified an orbital fracture with associated orbital and subcutaneous *** patient was evaluated by a plastic surgeon and was determined not to be a surgical *** weeks later,he returned to flying ***:Water balloons are thought to be safe and harmless ***,when coupled with sling shots,water balloons can become formidable projectiles capable of significant orbital injury including orbital *** injuries are concerning to aviators,as the most common sites for fractures of the orbit are the thin ethmoid and maxillary bones adjacent to the *** altitude,gases in the sinuses may expand and enter the orbit through these fractures,which may suddenly incapacitate the *** is important for flight surgeons to identify and assess these individuals to determine suitability for flying.

关键词： Boyle’s law Orbital emphysema Facial fracture