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Dvoyashkin, Muslim, Alexey Khokhlov, Rustem Valiullin, Jörg Kärger e Matthias Thommes. "Fluid behavior in porous silicon channels with complex pore structure". Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-190953.
Testo completo
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Dvoyashkin, Muslim, Alexey Khokhlov, Rustem Valiullin, Jörg Kärger e Matthias Thommes. "Fluid behavior in porous silicon channels with complex pore structure". Diffusion fundamentals 11 (2009) 80, S. 1-2, 2009. https://ul.qucosa.de/id/qucosa%3A14045.
Testo completo
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Kelich, Joseph M. "Single-Molecule Studies on Nuclear Pore Complex Structure and Function". Diss., Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/511772.
Testo completoAbstract (sommario):
BiologyPh.D.
Nuclear pore complexes (NPCs) are large macromolecular gateways embedded in the nuclear envelope of Eukaryotic cells that serve to regulate bi-directional trafficking of particles to and from the nucleus. NPCs have been described as creating a selectively permeable barrier mediating the nuclear export of key endogenous cargoes such as mRNA, and pre-ribosomal subunits as well as allow for the nuclear import of nuclear proteins and some viral particles. Remarkably, other particles that are not qualified for nucleocytoplasmic transport are repelled from the NPC, unable to translocate. The NPC is made up of over 30 unique proteins, each present in multiples of eight copies. The two primary protein components of the NPC can be simplified as scaffold nucleoporins which form the main structure of the NPC and the phenylalanine-glycine (FG) motif containing nucleoporins (FG-Nups) which anchor to the scaffold and together create the permeability barrier within the pore. Advances in fluorescence microscopy techniques including single-molecule and super-resolution microscopy have made it possible to label and visualize the dynamic components of the NPC as well as track the rapid nucleocytoplasmic transport process of importing and exporting cargoes. The focus of this dissertation will be on live cell fluorescence microscopy application in probing the dynamic components of the NPC as well as tracking the processes of nucleocytoplasmic transport.
Temple University--Theses
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Nordeen, Sarah Ann. "A nanobody suite for yeast scaffold nucleoporins provides details of the Y complex structure and nuclear pore complex assembly". Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127138.
Testo completoAbstract (sommario):
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biology, May, 2020Cataloged from the official PDF of thesis.
Includes bibliographical references.
Nuclear pore complexes (NPCs) are the main conduits for molecular exchange across the nuclear envelope. The NPC is a modular assembly of ~500 individual proteins, called nucleoporins or nups, that can be classified into three categories: 1. Stably associated scaffolding nups, 2. Peripheral nups, and 3. Phenylalanine-glycine (FG) repeat containing nups that form the permeability barrier of the NPC. Most scaffolding nups are organized in two multimeric subcomplexes, the Nup84 or Y complex and the Nic96 complex. Working in S. cerevisiae to study the assembly of these two essential subcomplexes, we developed a suite of twelve nanobodies that recognize seven constituent nucleoporins of the Y and Nic96 complexes. The nanobodies bind their targets specifically and with high affinity, albeit with varying kinetics. We mapped the epitope of eight members of the nanobody library via crystal structures of nup-nanobody co-complexes.
Nuclear pore complexes (NPCs) are the main conduits for molecular exchange across the nuclear envelope. The NPC is a modular assembly of ~500 individual proteins, called nucleoporins or nups, that can be classified into three categories: 1. Stably associated scaffolding nups, 2. Peripheral nups, and 3. Phenylalanine-glycine (FG) repeat containing nups that form the permeability barrier of the NPC. Most scaffolding nups are organized in two multimeric subcomplexes, the Nup84 or Y complex and the Nic96 complex. Working in S. cerevisiae to study the assembly of these two essential subcomplexes, we developed a suite of twelve nanobodies that recognize seven constituent nucleoporins of the Y and Nic96 complexes. The nanobodies bind their targets specifically and with high affinity, albeit with varying kinetics. We mapped the epitope of eight members of the nanobody library via crystal structures of nup-nanobody co-complexes.
In two cases, the nanobodies facilitated the crystallization of novel nup structures, namely the full-length Nup84-Nup133 [alpha]-helical domain structure and the Nup133 [beta]-propeller domain structure. Together these two structures completely characterize the S. cerevisiae Y complex molecular assembly. Further, the Nup133 [beta]-propeller domain contains a structurally conserved amphipathic lipid packing sensor (ALPS) motif thought to anchor the Y complex to the nuclear envelope, which we confirmed by liposome interaction studies. An additional nanobody facilitated the structure of Nic96 at an improved resolution, revealing previously missing helices. In addition to the utility of these nanobodies for in vitro characterization of NPC assemblies, we also show that expression of nanobody-fluorescent protein fusions reveals details of the NPC assembly in their native, in vivo environment, and possibly of NPC heterogeneity within the nuclear envelope.
Overall, this suite of nanobodies provides a unique and versatile toolkit for the study of the NPC.
by Sarah Ann Nordeen.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Biology
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Raneri, Simona. "Complex Pore Geometries in Natural Building Stones: an experimental and theoretical approach for the modeling of porosity changes in natural, degraded and treated calcarenites". Doctoral thesis, Università di Catania, 2016. http://hdl.handle.net/10761/4021.
Testo completoAbstract (sommario):
Calcarenites are the most widely used natural stones in Sicily as building materials. The comprehension of the degradation style of these natural building stone is of great interest in order to preserve the ancient masonry, especially in the case of relevant Cultural Heritages. A large number of Sicilian monuments are included in UNESCO Heritage List as their special cultural or physical significance. Considering the cultural importance of these ones, smart solutions are required in the perspective of their conservation.
In the framework of restoration actions, the complete knowledge of the internal structure of building stones is fundamental in order to estimate durability and prevent degradation processes. Salt growth is a significant cause of damage for natural stones. The effects of the salt weathering are, in addition to the properties of the salt itself and the climatic conditions, strongly related to the structural and textural features of materials. For this reason, an integrate study on petrographic, physical, mechanical and porosimetric proprieties changes due to salts crystallization could be useful to highlight correlation among textural, structural and engineering parameters. Moreover, one of the main problems in conservation field is the use of suitable consolidant and protective treatments able to preserve the masonry, being compatible with the stone substrate and not affecting its aesthetical proprieties. There are numerous tests able to verify the efficiency of consolidant or protective products, mainly devoted to verify their ability to not modify the appearance of stone and its physical proprieties, especially against water; however, particularly in the case of consolidant, one of the most important feature is related to its penetration depth, often difficult to evaluate by using the standard test routines.
For aforementioned, this research work is devoted to apply a multi-methodological approach for characterizing and modeling pore structure modifications due to weathering processes in a coarse grained Sicilian calcarenite used as building and replace stones in Sicilian Cultural Heritages (Sabucina Stone), also through fractal models and innovative and non invasive methods. The obtained data on Sabucina stone have been employed for planning conservative treatments devoted to coarse grained calcarenite substrates. Therefore, innovative nanostructured and hybrid consolidant and protective products have been experimented and the results of efficiency tests along with the determination of surface and sub-surface changes due to the treatments are proposed.
In conclusion, the applied theoretical and empirical approach has allowed to: highlight the potential of classical and innovative complementary methods in quantifying the structural changes in porous materials due to degradation processes and conservative treatments, explain how they help to facilitate the understanding of stone weathering and validate the use of geometrical models in describing complex pore systems.
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Kelley, Kotaro. "Structural and biochemical characterization of nuclear pore complex structural scaffold sub-complexes". Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113466.
Testo completoAbstract (sommario):
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biology, 2017Cataloged from PDF version of thesis.
Includes bibliographical references.
The nuclear pore complex (NPC) is a large, modular protein assembly that regulates nucleocytoplasmic transport in all eukaryotes. The ~60-120 MDa NPC is a modular assembly of multiple copies of ~30 distinct proteins that are arranged into biochemically distinct sub-complexes. We believe that the structural characterization of the NPC is essential for understanding its transport mechanisms and various pathologies and human diseases associated with deletions or mutations of constituents. To obtain detailed structural information of the NPC, techniques that span several resolution ranges are necessary due to its large size and complexity. For instance, recent progress in the structural characterization of the overall architecture of the NPC by cryo-electron tomography(cryo-ET) to ~23Å resolution has revealed its size, shape, and course arrangement, but lacks distinguishable protein-protein boundaries and secondary structural details.
Although the entire NPC is not amenable to high resolution X-ray crystallography, we complement the cryo-ET reconstructions with a divide and conquer approach by obtaining high resolution X-ray crystal structures of individual subcomplexes. By taking advantage of the modular nature of the NPC, we can dock subcomplexes into the cryo-ET reconstructions to identify their location within the NPC. This composite structure will bridge the meso resolution cryo-ET reconstructions of the entire NPC and the incomplete but high resolution X-ray crystal structure of individual subcomplexes. As a first step towards understanding the detailed organization of the NPC, our goal is to solve the high resolution structures of the two principal structural scaffold subcomplexes, the Y and Nic96 complexes. In this study, we present the high resolution composite X-ray crystal structure of the Y complex.
Docking the composite model into previously solved random conical tilt(RCT) and tomographic reconstructions of negatively stained samples of the Y complex shows overall consistency between the three methods, yet we highlight important structural differences that constrain possible arrangements of multiple Y complexes within the NPC. By docking the composite model into the cryo-ET reconstructions of the entire NPC, we propose an arrangement of multiple Y complexes that is consistent with our composite structure. In addition, progress on structurally characterizing the Nic96 complex will be presented. Preliminary results suggest that Nup1 92 and Nic96 form a flexible, yet semi-ordered interface. Future directions for characterizing the rest of the Nic96 complex, including current challenges and suggestions will be discussed.
by Kotaro Kelley.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Biology
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Chemudupati, Mahesh. "Investigating the effects of nuclear envelope proteins on nuclear structure and organization in Aspergillus nidulans". The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu148009978216118.
Testo completo
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Yacouba, Amani Abdoul Nasser. "Approche multi-géophysique pour la caractérisation de la fracturation et des propriétés de transport des roches carbonatées". Electronic Thesis or Diss., Orléans, 2024. http://www.theses.fr/2024ORLE1024.
Testo completoAbstract (sommario):
Dans un contexte de changements globaux et de transitions écologiques et énergétiques, le changement climatique induit une sècheresse récurrente et de crise de la ressource en eau dans plusieurs régions et continents. Il est donc crucial d'étudier les aquifères d'eaux douces afin d'accompagner ces transitions et assurer une gestion et une utilisation durable et raisonnée de cette ressource vitale. En l'occurrence, la zone vadose qui joue un rôle important dans la recharge de ces aquifères et le transfert d'éventuels polluants et d'intrants. La plupart du temps, cette zone non saturée en eau, se caractérise par la présence d'hétérogénéités (structure de pores, fractures, variation minéralogique) multi-échelles notamment lorsqu'il s'agit d'un milieu calcaire. Ces hétérogénéités sont complexifiées par les processus diagenétiques liés principalement à l'altération physico-chimique et minéralogique. La surimposition de ces phénomènes primaires et secondaires rend difficile l'estimation des propriétés pétrophysiques (porosité, perméabilité, saturation en eau) à partir des méthodes géophysiques. Parmi ces méthodes couramment utilisées, les méthodes acoustique et électrique sont bien adaptées car il existe, à priori, un lien étroit entre les hétérogénéités et les propriétés mesurées.Les travaux de recherche menés dans le cadre de cette thèse s'appuient ainsi sur une approche multi-géophysique permettant de mieux caractériser un réservoir carbonaté complexe en se basant notamment sur une analyse pétrophysique combinée à une description microstructurale fine.Dans ce travail, nous avons démontré l'influence de la microstructure sur la prédiction et la modélisation des propriétés pétroacoustiques ce qui conduit à une bonne discrimination de certains faciès, utile pour améliorer les modèles de simulation d'écoulements. De plus, ce travail a aussi permis de montrer la pertinence de la conductivité complexe dans la caractérisation des calcaires et la prédiction de leur perméabilité. Cependant, des développements supplémentaires sont nécessaires concernant la problématique du changement d'échelles des réservoirs complexes et hétérogènesIn a context of global changes and ecological and energy transitions, climate change induces recurrent drought and water resource crisis in several regions and continents. It is crucial to study groundwaters in order to support these transitions and ensure effective management and use of this vital resource. In particular, the vadose zone which plays an important role in the recharge of these groundwaters and the transfer of possible pollutants and inputs. Most of the time this unsaturated zone is characterized by multi-scale heterogeneities (e.g., pore structure, fractures, mineralogical variation) particularly in a limestone environment. These heterogeneities are complexified by diagenetic processes linked mainly to physicochemical and mineralogical alteration which leads to uncertainty in reservoir property (e.g., porosity, permeability, water saturation) estimation from geophysical methods. Among these methods, acoustic and electrical methods are well suited because of the strong relation between heterogeneities and the measured properties.This thesis relies on a multi-geophysical approach in order to better characterize a complex carbonate reservoir using petrophysical measurements combined with microstructural descriptions. Based on this approach, we demonstrated the influence of rock structure on the prediction and modeling of petroacoustic properties. This work leads to a good discrimination of some facies, which can be used to improve simulation and flow models. In addition, we demonstrate the relevance of complex conductivity measurements in limestone characterization and permeability prediction. However, additional developments are needed to understand the upscaling problematic for heterogeneous and complex reservoirs
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Walther, Tobias. "The role of Peripheral Nuclear Pore Complex (NPC) structures in nuclear transport and NPC architecture". Diss., lmu, 2002. http://nbn-resolving.de/urn:nbn:de:bvb:19-4945.
Testo completo
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Partridge, James R. (James Robert). "Biophysical and structural characterization of components from the nuclear pore complex and the ubiquitin pathway". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/57994.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 136-151).
Formation of an endomembrane system in the eukaryotic cell is a hallmark of biological evolution. One such system is the nuclear envelope (NE), composed of an inner and outer membrane, used to form a nucleus and enclose the cell's genome. Access to the nucleus from the cytoplasm is mediated by a massive macromolecular machine called the nuclear pore complex (NPC). The NPC resides as a circular opening embedded in the NE and is composed of only -30 proteins that assemble with octagonal symmetry as biochemically defined subcomplexes to form the NPC. One such subcomplex is the Nspl / Nup62 complex, composed of three proteins and stabilized by coiled-coil interactions. Here we reconstitute a tetrameric assembly between the Nspl-complex and a fourth nucleoporin (Nup) Nic96. Nic96 harbors a 20 kDa coiled-coil domain at the N-terminus followed by a 65 kDa stacked helical domain. The coiled-coil domain of the Nspl -complex and the N-terminus of Nic96 combine to form a tetrameric assembly, integrated into the NPC lattice scaffold via the stacked helical domain of Nic96. We characterized the coiled-coil assembly with size exclusion chromatography and analytical ultracentrifugation. Deletion experiments and point mutations, directed by hydrophobic cluster analysis, were used to map connecting helices between members of the protein assembly. Although the core of the NPC is a rigid scaffold built for structural integrity, the NPC as a whole is a dynamic macromolecular machine. Protein transport is regulated by the small G protein Ran. Ran interacts with the NPC of metazoa via two asymmetrically localized components, Nupl53 at the nuclear face and Nup358 at the cytoplasmic face. Both Nups contain distinct RANBP2 type zinc finger (ZnF) domains. We present crystallographic data detailing the interaction between Nup1 53-ZnFs and RanGDP. A crystal-engineering approach led to well-diffracting crystals so that all ZnF-Ran complex structures are refined to high resolution. Each of the four zinc finger modules of Nup1 53 binds one Ran molecule in largely independent fashion. Nupl53-ZnFs bind RanGDP with higher affinity than RanGTP, however the modest difference suggests that this may not be physiologically meaningful. ZnFs may be used to concentrate Ran at the NPC to facilitate nucleocytoplasmic transport. In a separate study we present a structural analysis of the HECT domain from the E3 ubiquitin ligase HUWE1 and with biophysical data we show that an N-terminal helix stabilizes the HECT domain. This element modulates activity, as measured by self-ubiquitination induced in the absence of this helix, distinct from its effects on Ub conjugation of substrate Mcl-1. Such subtle structural elements in this domain potentially regulate the variable substrate specificity displayed by all HECT domain type, E3 ubiquitin ligases.
by James R. Partridge.
Ph.D.
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Brohawn, Stephen Graf. "Structural elucidation of a common architecture of the nuclear pore complex and COPIl vesicle coats". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/58396.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 156-169).
Nuclear pore complexes (NPCs) are massive protein assemblies that perforate the nuclear envelope and form the exclusive passageway for nucleocytoplasmic transport. NPCs play critical roles in molecular transport and a myriad of other cellular processes. Elucidation of the structure of the NPC is thus expected to provide important insight into cell biology. In this thesis, I investigate the structure of a key subcomplex of the NPC and discuss the evolutionary relationship between the NPC and COPIl vesicle coats it illustrates. The NPC is a modular assembly, with a stable structural scaffold supporting dynamically attached components. The structural scaffold is constructed from multiple copies of the Y-shaped complex and the Nic96 complex. We solved the crystal structure of the heterodimeric Nup85-Sehl module that forms a short arm in the Y complex. Nup85 is found to contain a conserved fold, the ancestral coatomer element 1 (ACE1), also present in three other components of the NPC and in the COPI vesicle coat, providing structural evidence of coevolution from a common ancestor. Sec3l ACE1 units interact to form edge elements in the COPI lattice. Using structural knowledge of this edge element, we identified corresponding interactions between ACE1 proteins Nup84 and Nup145C in the NPC. We solved the crystal structure of the heterotrimeric Nup84-Nupl 45C-Secl 3 module that forms the top of the long arm in the Y complex. The heterotypic ACE1 interaction of Nup145C and Nup84 is analogous to the homotypic Sec31 edge element interaction in the COPIl coat. From these and other structures, we assemble a near complete structural model of the Y complex. Further, based on the demonstrated relationship with the COPIl coatomer lattice, we propose a lattice model for the entire NPC scaffold. The common architectural principles of the edge elements in the NPC and COPI lead us to predict that Y complexes will be arranged as struts in the NPC lattice. In this manner, Nup84-Nup145C edge elements are arranged parallel to the transport axis to stabilize the positively curved nuclear envelope. From a lattice model of the NPC follow hypotheses for how other components are integrated into and function within the NPC.
by Stephen Graf Brohawn.
Ph.D.
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Pignol, David. "Structures cristallines de la sous-unité III du complexe procarboxypeptidase A-S6 de boeuf et du zymogène de porc : une nouvelle classe de zymogènes ?" Université Joseph Fourier (Grenoble ; 1971-2015), 1994. http://www.theses.fr/1994GRE10082.
Testo completoAbstract (sommario):
La sous-unite trois, une endopeptidase inactive et reliee a la protease e, est secretee par le pancreas des ruminants au sein du complexe ternaire pcp-s6. Cette proteine est depourvue en n-terminal du dipeptide hydrophobe conserve chez les proteases a serine. Sa structure a ete resolue sur deux formes cristallines (a 2. 2 et 1. 7 a de resolution) par remplacement moleculaire. Les methodes d'affinement, classiquement utilisees en cristallographie biologique, ne nous ont pas permis d'obtenir le modele final. L'amelioration des phases a necessite l'utilisation d'une procedure d'affinement automatique (arp). Bien que 80% du modele presente une architecture de type trypsine, la conformation des boucles dites d'autolyse et de fixation du calcium, est unique et se differencie de celle observee dans toutes les structures connues de proteases a serine. La poche de specificite primaire de la sous-unite trois adopte une conformation de type zymogene, expliquant ainsi son inactivite. La structure du zymogene e de porc, le precurseur inactif de la protease e, a ete resolue a partir du modele de la sous-unite trois, a 2. 3 a de resolution. Ces deux structures sont tres proches, confirmant ainsi l'hypothese selon laquelle la sous-unite iii est issue de l'hydrolyse du zymogene e, constituant ab initio du complexe pcpa-s6. Ces deux membres de la famille de la protease e, correspondent a une nouvelle classe de zymogenes tres structures. Sur la base de leurs structures, nous proposons un mecanisme d'activation dans cette famille, impliquant de larges mouvements concertes
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Dulina, I. O., T. F. Lobunets e A. V. Ragulya. "Relationships Between Pore Structure, Free Carbon Content, Particle Size Distribution and Deposition Stage of Ni/NiO Nanopowers". Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/42718.
Testo completoAbstract (sommario):
Ni/NiO nanopowders have been prepared by using thermal decomposition of aqua solutions of nickel acetate ammine complexes in air at the annealing temperature range 300 – 500 ºC, time of decomposition from 30 to 180 min. Particle size of powders has been investigated by and scanning electron microscopy (SEM). Powders pore structure has been determinated by low temperature nitrogen adsorption method. Content of free carbon in powders is determitated by stage of decomposition and annealing temperature. Decomposition of hydroxy-containing precursor at occurred in 3 stages: 1) the primary formation of Ni; 2) decomposition of precursors with formation of NiO; 3) afterreduction of NiO to Ni by residuals of organic compounds and ammonia. The first two stages is characterized by highly endothermic effect that can lead to decreasing of acetic acid evaporation rate and resulted in high free carbon content of powders. Increasing of deposition time permits to remove of acetic acid from particle surface and decrease free carbon content in powder.
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Farr, Julia Christina [Verfasser], e Berenike [Akademischer Betreuer] Maier. "Structural and functional analysis of the nuclear pore complex in Saccharomyces cerevisiae / Julia Christina Farr ; Betreuer: Berenike Maier". Münster : Universitäts- und Landesbibliothek Münster, 2009. http://d-nb.info/1140917676/34.
Testo completo
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Loing, Vianney. "Stéréotomie et vision artificielle pour la construction robotisée de structures maçonnées complexes". Thesis, Paris Est, 2019. http://www.theses.fr/2019PESC1015/document.
Testo completoAbstract (sommario):
Ce travail de thèse s'inscrit dans le contexte du développement de la robotique dans la construction. On s’intéresse ici à la construction robotisée de structures maçonnées complexes en ayant recours à de la vision artificielle. La construction sans cintre étant un enjeu important en ce qui concerne la productivité sur un chantier et la quantité de déchets produits, nous explorons, à cet effet, les possibilités qu'offre la rigidité en flexion inhérente aux maçonneries topologiquement autobloquantes. La génération de ces dernières, classique dans le cas plan, est généralisée ici à la conception de structures courbes, à partir de maillages de quadrangles plans et de manière paramétrique, grâce aux logiciels Rhinoceros 3D / Grasshopper. Pour cela, nous proposons un ensemble d'inégalités à respecter afin que la structure obtenue soit effectivement topologiquement autobloquante. Ces inégalités permettent, par ailleurs, d'introduire un résultat nouveau ; à savoir qu'il est possible d'avoir un assemblage de blocs dans lequel chacun des blocs est topologiquement bloqué en translation, mais un sous-ensemble — constitué de plusieurs de ces blocs — ne l'est pas. Un prototype de maçonnerie à topologie autobloquante est finalement conçu. Sa conception repose sur une découpe des joints d'inclinaison variable qui permet de le construire sans cintre. En parallèle, nous abordons des aspects de vision artificielle robuste pour un environnement chantier, environnement complexe dans lequel les capteurs peuvent subir des chocs, être salis ou déplacés accidentellement. Le problème est d'estimer la position relative d'un bloc de maçonnerie par rapport à un bras robot, à partir de simples caméras 2D ne nécessitant pas d'étape de calibration. Notre approche repose sur l'utilisation de réseaux de neurones convolutifs de classification, entraînés à partir de centaines de milliers d'images synthétiques de l’ensemble bras robot + bloc, présentant des variations aléatoires en terme de dimensions et positions du bloc, textures, éclairage, etc, et ce afin que le robot puisse apprendre à repérer le bloc sans trop de biais d’environnement. La génération de ces images est réalisée grâce à Unreal Engine 4. Cette méthode permet la localisation du bloc par rapport au robot avec une précision millimétrique, sans utiliser une seule image réelle pour la phase d'apprentissage ; ce qui constitue un avantage certain puisque l'acquisition de données représentatives pour l'apprentissage est un processus long et fastidieux. Nous avons également construit une base de données riche, constituée d’environ 12000 images réelles contenant un robot et un bloc précisément localisés, permettant d’évaluer quantitativement notre approche et de la rendre comparable aux approches alternatives. Un démonstrateur réel intégrant un bras ABB IRB 120, des blocs parallélépipédiques et trois webcams a été mis en place pour démontrer la faisabilité de la méthodeThe context of this thesis work is the development of robotics in the construction industry. We explore the robotic construction of complex masonry structures with the help of computer vision. Construction without the use of formwork is an important issue in relation to both productivity on a construction site and the amount of waste generated. To this end, we study topological interlocking masonries and the possibilities they present. The design of this kind of masonry is standard for planar structures. We generalize it to the design of curved structures in a parametrical way, using PQ meshes and the softwares Rhinoceros 3D and Grasshopper. To achieve this, we introduce a set of inequalities to respect in order to have a topological interlocked structure. These inequalities allow us to present a new result. Namely, it is possible to have an assembly of blocks in which each block is interlocked in translation, while having a subset — composed of several of these blocks — that is not interlocked. We also present a prototype of topological interlocking masonry. Its design is based on variable inclination joints, allowing construction without formwork. In parallel, we are studying robust computer vision for unstructured environments like construction sites, in which sensors are vulnerable to dust or could be accidentally jostled. The goal is to estimate the relative pose (position + orientation) of a masonry block with respect to a robot, using only cheap cameras without the need for calibration. Our approach relies on a classification Convolutional Neural Network trained using hundreds of thousands of synthetically rendered scenes with a robot and a block, and randomized parameters such as block dimensions and poses, light, textures, etc, so that the robot can learn to locate the block without being influenced by the environment. The generation of these images is performed with Unreal Engine 4. This method allows us to estimate a block pose very accurately, with only millimetric errors, without using a single real image for training. This is a strong advantage since acquiring representative training data is a long and expensive process. We also built a new rich dataset of real robot images (about 12,000 images) with accurately localized blocks so that we can evaluate our approach and compare it to alternative approaches. A real demonstrator, including a ABB IRB 120 robot, cuboid blocks and three webcams was set up to prove the feasibility of the method
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Böhmer, Thomas. "Functional and structural dissection of Nup107 and Nup133, two members of the Nup107-160 subcomplex, linchpin of the vertebrate nuclear pore complex". [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975117866.
Testo completo
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Dulina, I. O., T. F. Lobunets, L. O. Klochkov e A. V. Ragulya. "Synthesis of Ni/NiO Nanosize Powders with Different Phase Ratio by Thermal Decomposition of Nickel Acetate Amines". Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35125.
Testo completoAbstract (sommario):
Ni/NiO nanopowders with different phase ratio have been prepared using thermal decomposition of nickel acetate ammine complexes containing various ammonia content in air at the temperature range 300 – 500 °C. Obtained powders have been characterized by IR-spectroscopy, XRD and TG, DTA, DTG, TEM, laser granulometry and adsorption-structural method. Thermal decomposition of nickel ammine complexes occurred with forming nickel hydroxide, carbonate and hydroxocarbonate ammines precursors. Composition of the precursors depended on temperature and ammonia content in initial complex. Mean crystallite size of nickel depended on temperature only. In the temperature range from 350 to 500 °C the crystallite size of nickel has grown from 50 to 55 nm. Mean crystallite size of nickel oxide depended on temperature and ammonia content. In the temperature range from 350 to 500 °C the crystallite size of NiO has grown from 5 to 25 nm. Increasing ammonia content from 3.6 to 14.4 mol/mol Ni led to decreasing NiO crystallite size from 8 – 10 to 5 nm.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35125
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Gaik, Monika [Verfasser], e Ed [Akademischer Betreuer] Hurt. "Structural and Functional Characterization of the Conserved Nup82 Subcomplex Located on the Cytoplasmic Side of the Yeast Nuclear Pore Complex / Monika Gaik ; Betreuer: Ed Hurt". Heidelberg : Universitätsbibliothek Heidelberg, 2015. http://d-nb.info/1180394887/34.
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Shmykov, Egor. "Sportovní centrum Brno". Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225829.
Testo completoAbstract (sommario):
This paper deals with the sport complex of Brno. This sport complex consist of buildings which are called to increase of sport popularity in the city. One of the largest objekt of them is footbal stadium. Footbal stadium is devided into three main parts of building: spectators area, administrative todether with commentators area, and footbal players area. There is secured parking on -1 level for employees, players and VIP spectators. Of course there are necessary medical, secure and sanitary placements. With the architectural part of view footbal stadium add a reqired part of masterplan composition. As Stadium exist on the cross roads of Pionyrska and Sportovni it supplement around area of its tactic form an closely interact with park "Luzanky" thanks to it's glass fasade. The building is designed to meet every safety regulations regarding evacuation routes and required medical care. It also carries a number of place improvements not only technical and functional, but a lot of with architectural part of view.
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Miao, Mi. "Analysis of integral membrane protein Pom34p in nuclear pore complex structure and function". Diss., 2007. http://etd.library.vanderbilt.edu/ETD-db/available/etd-03272007-141235/.
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Nagy, Vivien [Verfasser]. "Structural analysis of an essential core component of the nuclear pore complex / vorgelegt von Vivien Nagy". 2010. http://d-nb.info/1010669753/34.
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Walther, Tobias Christian [Verfasser]. "The role of peripheral nuclear pore complex (NPC) structures in nuclear transport and NPC architecture / von Tobias Christian Walther". 2002. http://d-nb.info/965860906/34.
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Port, Sarah A. "Structural and Functional Characterization of CRM1-Nup214 Interactions Reveals Multiple FG-binding Sites Involved in Nucleocytoplasmic Transport". Doctoral thesis, 2015. http://hdl.handle.net/11858/00-1735-0000-0023-9611-C.
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Böhmer, Thomas [Verfasser]. "Functional and structural dissection of Nup107 and Nup133, two members of the Nup107-160 subcomplex, linchpin of the vertebrate nuclear pore complex / vorgelegt von Thomas Böhmer". 2005. http://d-nb.info/975117866/34.
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Jadidi, Tayebeh. "In-silico Modeling of Lipid-Water Complexes and Lipid Bilayers". Doctoral thesis, 2013. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2013102111709.
Testo completoAbstract (sommario):
In the first part of the thesis, the molecular structure and electronic properties of phospholipids at the single molecule level and also for a monolayer structure are investigated via ab initio calculations under different degrees of hydration. The focus of the study is on phosphatidylcholines, in particular dipalmitoylphosphatidylcholine (DPPC), which are the most abundant phospholipids in biological membranes. Upon hydration, the phospholipid shape into a sickle-like structure. The hydration dramatically alters the surface potential, dipole and quadrupole moments of the lipids, and probably guides the interactions of the lipids with other molecules and the communication between cells. The vibrational spectrum of DPPC and DPPC-water complexes are completely assigned and it is shown that water hydrating the lipid head groups enables efficient energy transfer across membrane leaflets on sub-picosecond time scales. Moreover, the vibrational modes and lifetimes of pure and hydrated DPPC lipids, at human body temperature, are estimated by performing ab initio molecular dynamics simulations. The vibrational modes of the water molecules close to the head group of DPPC are active in the frequency range between 0.5 - 55 THz, with a peak at 2.80 THz in the energy spectrum. The computed lifetimes for the high-frequency modes agree well with recent data measured at room temperature, where high-order phonon scattering is not negligible. The structure and auto-ionization of water at the water-phospholipid interface are investigated by ab initio molecular dynamics and ab initio Monte Carlo simulations using local density approximation and generalized gradient approximation for the exchange-correlation energy functional. Depending on the lipid head group, strongly enhanced ionization is observed, leading to dissociation of several water molecules into H+ and OH- per lipid. The results can shed light on the phenomena of the high proton conductivity along membranes that has been reported experimentally. In the second part of the thesis, Monte Carlo simulations of the lipid bilayer, on the basis of a coarse grained model, are performed to gain insight into the mechanical properties of planar lipid bilayers. By using a rescaling method, the Poisson's ratio is calculated for different phases. Additional information on the bending rigidity, determined from height fluctuations on the basis of the Helfrich Hamiltonian, allows for calculation of the Young's modulus for each phase. In addition, the free energy barrier for lipid flip-flop process in the fluid and gel phases are estimated. The main rate-limiting step to complete a flip-flop process is related to a free energy barrier that has to be crossed in order to reach the center of the bilayer. The free energy cost for performing a lipid flip-flop in the gel phase is found to be five times greater than in the fluid phase, demonstrating the rarity of such events in the gel phase. Moreover, an energy barrier is estimated for formation of transient water pores that often precedes lipid translocation events and accounts for the rate-limiting step of these pore-associated lipid translocation processes.