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Finite-Size Conformational Transitions: A Unifying Concept Underlying Chromosome Dynamics

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Communications in Theoretical Physics 2014年第10期61卷 607-616页

作者： Bertrand R.caré Pascal carrivain Thierry Forné Jean-Marc Victor Annick Lesne Laboratoire de Physique Théorique de la Matière Condensée CNRS UMR 7600UPMC University Paris 06F-75005ParisFrance CNRS GDR 3536 UPMC University Paris 06F-75005ParisFrance Institut de Génétique Humaine CNRS UPR 1142 MontpellierFrance Institut de Génétique Moléculaire de Montpellier CNRS UMR 5535University of MontpellierMontpellierFrance Kavli Institute for Theoretical Physics China CAS

Investigating average thermodynamic quantities is not sufficient to understand conformational transitions of a finite-size polymer. We propose that such transitions are better described in terms of the probability distribution of some finite-size order parameter, and the evolution of this distribution as a control parameter varies. We demonstrate this claim for the coil-globule transition of a linear polymer and its mapping onto a two-state model. In a biological context, polymer models delineate the physical constraints experienced by the genome at different levels of organization,from DNA to chromatin to chromosome. We apply our finite-size approach to the formation of plectonemes in a DNA segment submitted to an applied torque and the ensuing helix-coil transition that can be numerically observed, with a coexistence of the helix and coil states in a range of parameters. Polymer models are also essential to analyze recent in vivo experiments providing the frequency of pairwise contacts between genomic loci. The probability distribution of these contacts yields quantitative information on the conformational fluctuations of chromosome regions. The changes observed in the shape of the distribution when the cell type or the physiological conditions vary may reveal an epigenetic modulation of the conformational constraints experienced by the chromosomes.

关键词： coil-globule transition helix-coil transition chromosome conformational capture two-state model

A Theory of the Risk for empirical CVaR with Application to Portfolio Selection

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Journal of Systems Science & Complexity 2021年第5期34卷 1879-1894页

作者： ARICI Giorgio CAMPI Marco C. care Algo DALAI Marco RAMPONI Federico A. Department of Information engineering University of Bresciavia Branze 3825123 BresciaItaly.

When decisions are based on empirical observations,a trade-off arises between flexibility of the decision and ability to generalize to new *** this paper,we focus on decisions that are obtained by the empirical minimization of the Conditional Value-at-Risk(CVa R)and argue that in CVa R the trade-off between flexibility and generalization can be understood on the ground of theoretical results under very general assumptions on the system that generates the *** results have implications on topics related to order and structure selection in various applications where the CVa R risk-measure is used.A study on a portfolio optimization problem with real data demonstrates our results.

关键词： Distribution-free results empirical CVa R generalization order selection risk scenario approach

Species,growth form,and biogeographic diversity of summit vegetation along an elevation gradient in the tropical Andes:a baseline for climate change monitoring

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Journal of Mountain Science 2022年第12期19卷 3441-3457页

作者： Luis D.LLAMBI Luis e.GAMeZ Roxibell PeLAYO carmen J.AZOcar Jesus e.TORReS Nelson J.MARQUeZ Monica B.BeRDUGO Francisco CUeSTA Lirey A.RAMIReZ Institute of environmental and ecological Sciences(ICAe) University of Los AndesMérida5101Venezuela Consorcium for Susteinable Development of the Andean eco-Region(CONDeSAN) Calle Germán Alemán E12-123Quito170504Ecuador Laboratory of Dendrology Environmental and Forestry FacultyUniversity of Los AndesMérida5101Venezuela ecological Plant Geography Faculty of GeographyUniv.of MarburgDeutschhausstrasse 10Marburg35032Germany Group of Biodiversity Environment and Health Research(BIOMAS)University of Las AméricasQuito170125Ecuador

Tropical alpine ecosystems exhibit outstanding plant diversity and endemism while being particularly sensitive to the impacts of climate *** understanding spatiotemporal changes in plant species composition,richness and community structure along tropical alpine altitudinal gradients is of primary importance,both the functional and historical/biogeographic dimensions of vegetation diversity remain largely *** used Generalized Linear Models and multivariate analyses to assess changes in species,growth forms,and biogeographic groups richness and abundance,in response to habitat variables along an elevation gradient in seven summits(3800 to 4600 m asl)in the Venezuelan Andes,studied using the standardized approach of the GLORIA-Andes monitoring *** habitat variables assessed were soil temperature(-10 cm),soil organic matter,slope inclination,and substrate *** found 113 species,representing72 genera,32 families,13 growth forms,and seven biogeographic origins,that included 25%of endemic *** observed richer vegetation,both in terms of species and growth forms,in summits with higher soil temperatures and higher SOM content,as well as higher biogeographic origin richness with increasing soil *** presence of holarctic elements increased toward higher elevations,while the occurrence of austral antarctic elements increased toward lower *** results indicate that biogeographic and functional approaches to vegetation diversity capture well the effect of abiotic filtering on community structuring in these tropical alpine *** findings constitute an important baseline for monitoring vegetation dynamics linked to climate change in the Venezuelan Andes by highlighting the functional and historical perspective on vegetation analyses,in contrast with more traditional approaches,based only on taxonomic species diversity.

关键词： Alpine vegetation Biogeography elevation gradient Functional diversity Páramo Soil organic matter Temperature Tropical Andes

Atlas of minimally invasive surgery

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Contribution of CT Scanning in the Investigation of Cranioencephalic Lesions in Bangui

2009年

作者： [edited by] Constantine T. Frantzides Mark A. car

来源：畅想之星图书光盘版（南... 评论

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Open Journal of Radiology 2024年第3期14卷 156-165页

作者： Bangue Songrou Francky Kouandongui Timothée Mobima Borel Tambala Yannick Héritier Sombot-Soule Stéphane Kouzou Judith Guiaba Kette euloge Tapiade Bidan Richard Bazogo National Center of Medical Imaging of Bangui Bangui Central African Republic Maman elisabeth DOMITIeN Hospital Bangui Central African Republic Community Hospital of Bangui Bangui Central African Republic

Introduction: Cranioencephalic exploration has always played a major role in CT scans. In the Central Africa Republic (car), the lack of cross-sectional imaging before the year 2020 meant that no study had focused on cranioencephalic lesions. The aim of this study was to contribute to improving the management of cranioencephalic pathologies in car. Patients and Method: The study took place at the Bangui National Medical Imaging Centre (CNIMB). It was a retrospective study over a two-year period (March 1, 2021 to February 30, 2023). All patients referred for cranioencephalic CT scans were included, regardless of age or sex. Results: 1745 CT scans were performed, 575 of which were cranioencephalic CT scans. The majority of patients were male (53%). Most lived in the capital Bangui (90.9%). Patients aged 61 and over were the most representative. The distribution of patients by requesting department showed that the reception and emergency department was one of the least requesting departments. The main abnormalities observed were strokes, 82.1% of which were ischaemic strokes and 17.9% haemorrhagic strokes. Strokes were followed by degenerative lesions. Post-traumatic injuries included haemorrhagic contusions (38.3%), subdural haematomas in 20.5% of cases, and extradural haematomas (9.3%). Craniofacial lesions (fractures) were observed in 45.8% of cases. Conclusion: Cranioencephalic scans accounted for 1/3 of CT examinations performed during the study period. It revealed pathologies that could not be detected by conventional means. All in all, CT scans contributed to the diagnosis of cerebral pathologies.

关键词： Cranioencephalic Scan National Medical Imaging Centre Bangui

Influence of biological maturation on cardiac autonomic recovery in female volleyball players during&after repeated sprints training:An experimental trial

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Sports Medicine and Health Science 2024年第3期6卷 279-286页

作者： Paulo Francisco de Almeida-Neto Fernanda Cristina Silva de Oliveira Jose Marcondes de Oliveira-Júnior Júlio Cesar Medeiros Alves Matheus de Lima Rocha Iago Medeiros da Silva Roberto Felipe C^amara Rocha Paulo Moreira Silva Dantas Breno Guilherme de Araújo Tin^oco Cabral Health Sciences Center Federal University of Rio Grande do NorteCCS-UFRNNatal59012-570RNBrazil Department of Physical education Federal University of Rio Grande do NorteDEF-UFRNNatal59078-970RNBrazil

Previously,it was suggested that biological maturation(BM)could be linked to cardiac autonomic recovery(car)in the pediatric ***,this influence hasn’t been confirmed *** aim was to investigate the impact of BM on car in female volleyball *** study with a sample of 38 volleyball players,comprising 20 girls(age:[11.62.1]years)and 18 women(age:[24.55.5]years),we analyzed BM,comparing maturing subjects(girls)with mature subjects(women).Additionally,we assessed peak height velocity(PHV)in *** conducted a training session involving repeated sprints(3 rounds of 6 sprints interspersed by 5 min[min]of passive rest).Using short-range radio telemetry,we analyzed car during(at the end of the 1st and 2nd rounds)and after(following the 3rd round)the training session of repeated sprints by applying the 60-s to 300-s heart rate recovery index(HRR-Index).Girls exhibited superior car compared to women(round 2:60-s,120-s,240-s,and 300-s,pes of BM indicated that individuals in the Late-PHV stage demonstrated superior car compared to those in the early-PHV and During-PHV groups.(60-s to 300-s,η2p>0.4,pects in the During-PHV stage were superior to those in the early-PHV stage(240-sa 300-s,η2 p>0.4,pe have concluded that biological maturation has a significant impact on cardiac autonomic recovery.

关键词： exercise Sport Volleyball Heart rate Pediatric

考虑制动、荷载转移、纵坡的雨天小客车弯道安全车速模型

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重庆交通大学学报（自然科学版） 2024年第2期43卷 75-83页

作者：许金良曾卓穆明浩俄广迅长安大学公路学院陕西西安710054 山东高速集团有限公司创新研究所山东济南250101

为了确定降雨环境下小客车弯道安全车速,基于瞬时轴线,建立了考虑纵坡、制动加速度及轮胎荷载转移的小客车侧滑速度模型;通过实地采集不同水膜厚度下的摩擦系数,得到了这二者之间的回归方程;结合摩擦椭圆原理,得到了考虑制动、驾驶人行... 详细信息

为了确定降雨环境下小客车弯道安全车速,基于瞬时轴线,建立了考虑纵坡、制动加速度及轮胎荷载转移的小客车侧滑速度模型;通过实地采集不同水膜厚度下的摩擦系数,得到了这二者之间的回归方程;结合摩擦椭圆原理,得到了考虑制动、驾驶人行为特性的综合摩擦系数分配方法;提出确定弯道车速的计算流程图,得到了不同降雨强度下以横向侧滑和纵向停车为指标的弯道车速。研究结果表明:当水膜厚度为0时,得到的侧滑速度值比点质量模型低35%左右;当水膜厚度小于2 mm时,摩擦系数降低最快,对车速影响最大;当水膜厚度大于2 mm时,摩擦系数变化幅度小且规律不明显;降雨对小客车弯道安全车速影响显著,仅小雨时就会导致车速平均降低15%左右;取一般最小半径计算时,不同降雨强度下的纵向停车速度均小于横向侧滑速度。

关键词：交通工程降雨环境摩擦系数车辆侧滑弯道车速

Protein adsorption, cell viability and corrosion properties of Ti6Al4V alloy treated by plasma oxidation and anodic oxidation

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International Journal of Minerals,Metallurgy and Materials 2020年第9期27卷 1269-1280页

作者： ÖzgüBayrak Hojjat Ghahramanzadeh Asl Ayşe Ak Department of Mechanical engineering Erzincan Binali Yıldırım UniversityErzincan 24100Turkey Department of Mechanical engineering Karadeniz Technical UniversityTrabzon 61080Turkey Vocational School of Health Services Medical Imaging Techniques ProgrammeKocaeli UniversityKocaeli 41001Turkey

The hardness,wettability,and electrochemical properties of Ti6Al4V alloy surfaces treated with anodic oxidation and plasma oxidation as well as the viabilities of the different cell lines on the obtained surfaces were *** anodic oxidation was performed for 10 min under 100 V potential,and it resulted in a 0.95μm thick nanoporous anatase-TiO2 *** the other hand,plasma oxidation was carried out at 650℃ for 1 h and resulted in a dense rutile-TiO2 structure with a thickness of 1.2μ*** a hardness of HV0.025823 and roughness of^220 nm were obtained by plasma oxidation,those obtained by anodic oxidation were HV0.025512 and^130 nm,*** anodic oxidation process created a more hydrophilic surface with a contact angle of 87.2°.Both oxidation processes produced similar properties in terms of corrosion behavior and showed better resistance than the as-received state in a certain range of ***,the surface treatments led to no significant change in the protein adsorption levels,which indicates that the difference in viability between the osteoblast and fibroblast cells was not due to the difference in surface protein *** all the factors,the surfaces obtained by anodic oxidation treatment revealed higher cell viability than those obtained by plasma oxidation(p=0.05).

关键词： Ti6Al4V oxidation corrosion cell viability protein adsorption

Two New Aporphine Alkaliods from Fissistigma bracteolatum

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Chinese Chemical Letters 2002年第9期13卷 862-864页

作者： Yu DeNG Jin CHeN Feng e WU Chengdu Institute of Biology Chinese Academy of SciencesChengdu 610041

1,2-methylenedioxy-9-methoxy-N-methoxycarbonyl-aporphine and 1,2-methylenedioxy -8,9-dimethoxy-N-methoxycarbonyl-aporphine, two new alkaloids possessing a N-(methoxy carbonyl) group have been isolated from the stems o... 详细信息

关键词： Fissistigma bracteolatum aporphine 1,2-methylenedioxy-9-methoxy-N-methoxy car- bonyl-aporphine 1,2-methylenedioxy -8,9-dimethoxy-N-methoxycarbonyl-aporphine.