Articoli di riviste: "Complex pore structure"

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Panté, Nelly. "Nuclear Pore Complex Structure". Developmental Cell 7, n. 6 (dicembre 2004): 780–81. http://dx.doi.org/10.1016/j.devcel.2004.11.010.

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Goldberg, Martin W., Irena Solovei e Terence D. Allen. "Nuclear Pore Complex Structure in Birds". Journal of Structural Biology 119, n. 3 (agosto 1997): 284–94. http://dx.doi.org/10.1006/jsbi.1997.3877.

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Hoelz, André, Erik W. Debler e Günter Blobel. "The Structure of the Nuclear Pore Complex". Annual Review of Biochemistry 80, n. 1 (7 luglio 2011): 613–43. http://dx.doi.org/10.1146/annurev-biochem-060109-151030.

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Aebi, Ueli. "Nuclear Pore Complex Structure, Conservation and Plasticity". Biophysical Journal 98, n. 3 (gennaio 2010): 13a. http://dx.doi.org/10.1016/j.bpj.2009.12.081.

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Miller, M., M. K. Park e J. A. Hanover. "Nuclear pore complex: structure, function, and regulation." Physiological Reviews 71, n. 3 (luglio 1991): 909–49. http://dx.doi.org/10.1152/physrev.1991.71.3.909.

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Lin, Daniel H., e André Hoelz. "The Structure of the Nuclear Pore Complex (An Update)". Annual Review of Biochemistry 88, n. 1 (20 giugno 2019): 725–83. http://dx.doi.org/10.1146/annurev-biochem-062917-011901.

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The nuclear pore complex (NPC) serves as the sole bidirectional gateway of macromolecules in and out of the nucleus. Owing to its size and complexity (∼1,000 protein subunits, ∼110 MDa in humans), the NPC has remained one of the foremost challenges for structure determination. Structural studies have now provided atomic-resolution crystal structures of most nucleoporins. The acquisition of these structures, combined with biochemical reconstitution experiments, cross-linking mass spectrometry, and cryo–electron tomography, has facilitated the determination of the near-atomic overall architecture of the symmetric core of the human, fungal, and algal NPCs. Here, we discuss the insights gained from these new advances and outstanding issues regarding NPC structure and function. The powerful combination of bottom-up and top-down approaches toward determining the structure of the NPC offers a paradigm for uncovering the architectures of other complex biological machines to near-atomic resolution.

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Zhu, Boyuan, Jianghui Meng, Chen Song, Renfang Pan, Zhengping Zhu e Jineng Jin. "Complexity and Heterogeneity Evaluation of Pore Structures in the Deep Marine Shale Reservoirs of the Longmaxi Formation, China". Journal of Marine Science and Engineering 11, n. 8 (17 agosto 2023): 1613. http://dx.doi.org/10.3390/jmse11081613.

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The structural evolution and sedimentary differentiation of the Sichuan Basin in China are complex, with intricate reservoir pore structures that significantly impact shale gas production. This study examines the complexity and heterogeneity of the microscopic pore structures in the deep marine shale reservoir in the Longmaxi Formation. Pore structure characterization techniques are used to compare deep and shallow–medium marine shales, and siliceous and silty shales. The results reveal the factors influencing pore structure and their impact on exploration and development. The key points are as follows: (1) The pore structure of deep siliceous shale is the most complex due to its diverse range of pore development patterns, pore types, and sizes. (2) The box dimension of full pore size is about 1.52 for deep marine shale and 1.46 for shallow–medium shale. Organic matter (OM) content, the degree of pore development, and inorganic mineral content all correlate positively with the complexity of the pore structure in deep marine shale, which affects the formation of high-quality reservoirs. (3) Lateral heterogeneity of pore structures shows strong regional variations in the study area. Heterogeneity is more pronounced in the deep marine shale than in the medium and shallow shale formations. OM mesopores significantly influence the overall heterogeneity of the shale pore system. The deep marine shale reservoir is situated in an area with strong regional variations. The pore structure of high-quality reservoirs is more complex than those of shallow–medium marine shales, displaying notable heterogeneity. Pore structures with fractal dimension values close to that of the shallow–medium formations (box dimensions within 1.5) offer promising targets for the exploration and development of deep marine shale gas.

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Kiseleva, Elena M., Martin W. Goldberg, Janet Cronshaw e Terence D. Allen. "The Nuclear Pore Complex: Structure, Function, and Dynamics". Critical Reviews in Eukaryotic Gene Expression 10, n. 1 (2000): 12. http://dx.doi.org/10.1615/critreveukargeneexpr.v10.i1.110.

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Forbes, D. J. "Structure and Function of the Nuclear Pore Complex". Annual Review of Cell Biology 8, n. 1 (novembre 1992): 495–527. http://dx.doi.org/10.1146/annurev.cb.08.110192.002431.

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Hampoelz, Bernhard, Amparo Andres-Pons, Panagiotis Kastritis e Martin Beck. "Structure and Assembly of the Nuclear Pore Complex". Annual Review of Biophysics 48, n. 1 (6 maggio 2019): 515–36. http://dx.doi.org/10.1146/annurev-biophys-052118-115308.

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Nuclear pore complexes (NPCs) mediate nucleocytoplasmic exchange. They are exceptionally large protein complexes that fuse the inner and outer nuclear membranes to form channels across the nuclear envelope. About 30 different protein components, termed nucleoporins, assemble in multiple copies into an intricate cylindrical architecture. Here, we review our current knowledge of the structure of nucleoporins and how those come together in situ. We delineate architectural principles on several hierarchical organization levels, including isoforms, posttranslational modifications, nucleoporins, and higher-order oligomerization of nucleoporin subcomplexes. We discuss how cells exploit this modularity to faithfully assemble NPCs.

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Schwartz, Thomas U. "The Structure Inventory of the Nuclear Pore Complex". Journal of Molecular Biology 428, n. 10 (maggio 2016): 1986–2000. http://dx.doi.org/10.1016/j.jmb.2016.03.015.

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Huang, Gaoxingyu, Chao Zeng e Yigong Shi. "Structure of the nuclear pore complex goes atomic". Current Opinion in Structural Biology 78 (febbraio 2023): 102523. http://dx.doi.org/10.1016/j.sbi.2022.102523.

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Rout, Michael P. "Structure-Function Mapping of the Nuclear Pore Complex". Biophysical Journal 116, n. 3 (febbraio 2019): 150a. http://dx.doi.org/10.1016/j.bpj.2018.11.833.

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Rout, Michael P., John D. Aitchison, Adisetyantari Suprapto, Kelly Hjertaas, Yingming Zhao e Brian T. Chait. "The Yeast Nuclear Pore Complex". Journal of Cell Biology 148, n. 4 (21 febbraio 2000): 635–52. http://dx.doi.org/10.1083/jcb.148.4.635.

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An understanding of how the nuclear pore complex (NPC) mediates nucleocytoplasmic exchange requires a comprehensive inventory of the molecular components of the NPC and a knowledge of how each component contributes to the overall structure of this large molecular translocation machine. Therefore, we have taken a comprehensive approach to classify all components of the yeast NPC (nucleoporins). This involved identifying all the proteins present in a highly enriched NPC fraction, determining which of these proteins were nucleoporins, and localizing each nucleoporin within the NPC. Using these data, we present a map of the molecular architecture of the yeast NPC and provide evidence for a Brownian affinity gating mechanism for nucleocytoplasmic transport.

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Allen, T. D., G. R. Bcnnion, S. A. Rutherford, E. Kiscleva e M. W. Goldberg. "FEISEM, Form and Function in the Nuclear Pore Complex". Microscopy and Microanalysis 4, S2 (luglio 1998): 958–59. http://dx.doi.org/10.1017/s1431927600024910.

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Recent initiatives have resulted in a considerable increase in our understanding of the structure of the nuclear pore complex (NPC). The biochemical factors involved in both import and export have been rapidly characterised, with steady progress in the molecular dissection of the structural elements of the NPC, which is a unit of considerable molecular architecture (MW 125 kD), comprising an estimated 50- 100 different proteins. Despite this progress, the crucial molecular interactions involved in the mechanics of transport through the central transporter of the NPC remain unclear. NPC structure in Diptera, fish, (Fig 1) amphibians, birds and mammals shows a high degree of evolutionary conservation. 3D reconstructions of isolated yeast NPCs, show that the core structure is very similar to ‘higher’ organisms, but peripheral structures may be considerably reduced in structural complexity (1).Individual NPC components have been accessed in FEISEM by a variety of methods, including proteolysis,

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Reichelt, R., A. Holzenburg, E. L. Buhle, M. Jarnik, A. Engel e U. Aebi. "Correlation between structure and mass distribution of the nuclear pore complex and of distinct pore complex components." Journal of Cell Biology 110, n. 4 (1 aprile 1990): 883–94. http://dx.doi.org/10.1083/jcb.110.4.883.

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Nuclear pore complexes (NPCs) prepared from Xenopus laevis oocyte nuclear envelopes were studied in "intact" form (i.e., unexposed to detergent) and after detergent treatment by a combination of conventional transmission electron microscopy (CTEM) and quantitative scanning transmission electron microscopy (STEM). In correlation-averaged CTEM pictures of negatively stained intact NPCs and of distinct NPC components (i.e., "rings," "spoke" complexes, and "plug-spoke" complexes), several fine structural features arranged with octagonal symmetry about a central axis could reproducibly be identified. STEM micrographs of unstained/freeze-dried intact NPCs as well as of their components yielded comparable but less distinct features. Mass determination by STEM revealed the following molecular masses: intact NPC with plug, 124 +/- 11 MD; intact NPC without plug, 112 +/- 11 MD; heavy ring, 32 +/- 5 MD; light ring, 21 +/- 4 MD; plug-spoke complex, 66 +/- 8 MD; and spoke complex, 52 +/- 3 MD. Based on these combined CTEM and STEM data, a three-dimensional model of the NPC exhibiting eightfold centrosymmetry about an axis perpendicular to the plane of the nuclear envelope but asymmetric along this axis is proposed. This structural polarity of the NPC across the nuclear envelope is in accord with its well-documented functional polarity facilitating mediated nucleocytoplasmic exchange of molecules and particles.

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Zha, Xiaojun, Fuqiang Lai, Xuanbo Gao, Yang Gao, Nan Jiang, Long Luo, Yingyan Li et al. "Characteristics and Genetic Mechanism of Pore Throat Structure of Shale Oil Reservoir in Saline Lake—A Case Study of Shale Oil of the Lucaogou Formation in Jimsar Sag, Junggar Basin". Energies 14, n. 24 (14 dicembre 2021): 8450. http://dx.doi.org/10.3390/en14248450.

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The shale oil reservoir of the Lucaogou Formation in the Jimsar Sag has undergone tectonic movement, regional deposition and complex diagenesis processes. Therefore, various reservoir space types and complex combination patterns of pores have developed, resulting in an intricate pore throat structure. The complex pore throat structure brings great challenges to the classification and evaluation of reservoirs and the efficient development of shale oil. The methods of scanning electron microscopy, high-pressure mercury injection, low-temperature adsorption experiments and thin-slice analysis were used in this study. Mineral, petrology, pore throat structure and evolution process characteristics of the shale oil reservoir were analyzed and discussed qualitatively and quantitatively. Based on these studies, the evolution characteristics and formation mechanisms of different pore throat structures were revealed, and four progressions were made. The reservoir space of the Lucaogou Formation is mainly composed of residual intergranular pores, dissolved pores, intercrystalline pores and fractures. Four types of pore throat structures in the shale oil reservoir of the Lucaogou Formation were quantitatively characterized. Furthermore, the primary pore throat structure was controlled by a sedimentary environment. The pores and throats were reduced and blocked by compaction and cementation, which deteriorates the physical properties of the reservoirs. However, the dissolution of early carbonate, feldspar and tuffaceous minerals and a small amount of carbonate cements by organic acids are the key factors to improve the pore throat structure of the reservoirs. The genetic evolution model of pore throat structures in the shale oil reservoir of the Lucaogou Formation are divided into two types. The large-pore medium-fine throat and medium-pore medium-throat reservoirs are mainly located in the delta front-shallow lake facies and are characterized by the diagenetic assemblage types of weak compaction–weak carbonate cementation–strong dissolution, early medium compaction–medium calcite and dolomite cementation–weak dissolution. The medium-pore fine throats and fine-pore fine throats are mainly developed in shallow lakes and semi-deep lakes. They are characterized by the diagenetic assemblage type of strong compaction–strong calcite cementation–weak dissolution diagenesis. This study provides a comprehensive understanding of the pore throat structure and the genetic mechanism of a complex shale oil reservoir and benefits the exploration and development of shale oil.

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Wallace, B., e K. Ravikumar. "The gramicidin pore: crystal structure of a cesium complex". Science 241, n. 4862 (8 luglio 1988): 182–87. http://dx.doi.org/10.1126/science.2455344.

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Joong Kim, Seung, Javier Fernandez-Martinez, Ilona Nudelman, Yi Shi, Wenzhu Zhang, Barak Raveh, Paula Upla et al. "Structure and Functional Anatomy of the Nuclear Pore Complex". Biophysical Journal 114, n. 3 (febbraio 2018): 372a. http://dx.doi.org/10.1016/j.bpj.2017.11.2063.

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AEBI, U., M. JARNIK, R. REICHELT e A. ENGEL. "Structure, assembly and interactions of the nuclear pore complex". Cell Biology International Reports 14 (settembre 1990): 8. http://dx.doi.org/10.1016/0309-1651(90)90143-m.

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Xu, Chao, Zhihong Li, Hao He, Amy Wernimont, Yanjun Li, Peter Loppnau e Jinrong Min. "Crystal structure of human nuclear pore complex component NUP43". FEBS Letters 589, n. 21 (29 settembre 2015): 3247–53. http://dx.doi.org/10.1016/j.febslet.2015.09.008.

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LI, TIANYANG, ZIZHEN WANG, NIAN YU, RUIHE WANG e YUZHONG WANG. "NUMERICAL STUDY OF PORE STRUCTURE EFFECTS ON ACOUSTIC LOGGING DATA IN THE BOREHOLE ENVIRONMENT". Fractals 28, n. 03 (maggio 2020): 2050049. http://dx.doi.org/10.1142/s0218348x20500498.

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Existing methods of well-logging interpretation often contain errors in the exploration and evaluation of carbonate reservoirs due to the complex pore structures. The differences in frequency ranges and measurement methods deviated between the acoustic well logs and indoor ultrasonic tests cause inconsistent results. Based on the elastic wave equation and the principle of the control variable method, a 2D axisymmetric borehole model with complex pore structures was developed, and the numerical simulation method for acoustic log was constructed. The modeling results show that the power function can well describe the effects of pore structure on the acoustic waves, while the velocity of the Stoneley wave is not sensitive to the pore structure. Crack-like pores with pore aspect ratio (AR) less than 0.1 significantly affect the velocities of P- and S-waves, whereas “spherical” pores have fewer effects. The models with larger pore sizes have high velocities of P- and S-waves. The velocities calculated by the equivalent medium theory are always higher than the numerical simulation results. The velocity deviation caused by the difference in frequency is much smaller than the pore structure. A fractal approach to quantify the effects of pore structures is applied in the acoustic logging data. The fractal dimension increases with the pore AR or size when the porosity is constant, which can be described by a simple power function. This gives us new ideas and methods for pore structure evaluation in the lower frequency range than the conventional petrophysical model.

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Liu, Ying, Xueying Li, Jungwon Heo, Yuanzheng Sun, Younki Lee, Du-Hyun Lim, Hyo-Jun Ahn, Kwon-Koo Cho, Rong Yang e Jou-Hyeon Ahn. "Effect of Ordered Carbon Structures on Electrochemical Properties of Carbon/Sulfur Composites in Lithium-Sulfur Batteries". Journal of Nanoscience and Nanotechnology 20, n. 11 (1 novembre 2020): 7057–64. http://dx.doi.org/10.1166/jnn.2020.18835.

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In this paper, the relationship between the pore spatial structures, pore sizes, and pore types of highly ordered mesoporous CMK-based carbons (CMK-1, CMK-3, and CMK-5) and their electrochemical performance in Li-S batteries is investigated. CMK-1 has a complex spatial structure and small pores. The structure is good for limiting polysulfide in the pores, but not for rapid transfer of Li+ ions in the cell. CMK-3 and CMK-5 have similar spatial structures and pore sizes, but different pore types. Compared to the single pore structure of CMK-3, the bimodal pore structure of CMK-5 not only improves the electrolyte accessibility, but also increases the number of reaction sites, resulting in better electrochemical performance. Studying the correlation between the physical structure of carbon-based materials and their electrochemical performance in Li-S batteries will provide new insights for optimizing porous electrode materials.

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Finlay, D. R., E. Meier, P. Bradley, J. Horecka e D. J. Forbes. "A complex of nuclear pore proteins required for pore function." Journal of Cell Biology 114, n. 1 (1 luglio 1991): 169–83. http://dx.doi.org/10.1083/jcb.114.1.169.

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A family of proteins bearing novel N-acetylglucosamine residues has previously been found to be required to form functional nuclear pores. To begin to determine which of the proteins in this family are essential for pore function, antisera were raised to each of three members of the family, p62, p58, and p54. With these antisera, it was possible to deplete nuclear reconstitution extracts of the proteins and to test the depleted nuclei for nuclear transport. In the course of the experiments, it was found that the three proteins exist as a complex; antisera to any one, while specific on a protein blot, coimmunoprecipitated all three proteins. This complex of pore proteins is stable to 2 M salt, 2 M urea, and the detergent Mega 10, indicating the presence of specific and tight protein-protein interactions. By gel filtration, the complex has a molecular mass of 550-600 kD. Nuclei containing pores depleted of the complex are found to be defective for nuclear transport; moreover, we observe a strict linear correlation between the amount of complex present in nuclei and the amount of nuclear transport of which those nuclei are capable. Thus, the p62-p58-p54 complex defines a group of proteins with strong protein-protein interactions that form a unit of pore structure essential for pore function.

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Makarov, Alexandr A., Norma E. Padilla-Mejia e Mark C. Field. "Evolution and diversification of the nuclear pore complex". Biochemical Society Transactions 49, n. 4 (20 luglio 2021): 1601–19. http://dx.doi.org/10.1042/bst20200570.

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The nuclear pore complex (NPC) is responsible for transport between the cytoplasm and nucleoplasm and one of the more intricate structures of eukaryotic cells. Typically composed of over 300 polypeptides, the NPC shares evolutionary origins with endo-membrane and intraflagellar transport system complexes. The modern NPC was fully established by the time of the last eukaryotic common ancestor and, hence, prior to eukaryote diversification. Despite the complexity, the NPC structure is surprisingly flexible with considerable variation between lineages. Here, we review diversification of the NPC in major taxa in view of recent advances in genomic and structural characterisation of plant, protist and nucleomorph NPCs and discuss the implications for NPC evolution. Furthermore, we highlight these changes in the context of mRNA export and consider how this process may have influenced NPC diversity. We reveal the NPC as a platform for continual evolution and adaptation.

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Wu, Xin, Si Long e Guo Hui Li. "Fractal Study on the Complexity of Limestone Surface Pore Structure". Advanced Materials Research 548 (luglio 2012): 275–80. http://dx.doi.org/10.4028/www.scientific.net/amr.548.275.

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Complex characteristics of pore structure of rock mass, such as limestone, are difficult to describe by means of general mathematics and physics. While, the fractal geometry can describe some simple rules behind complex phenomena; and these simple rules can describe the complex phenomena. Therefore in this paper, the fractal theory is applied to study the complexity of the limestone pore structure. Through calculating the fractal dimension of the limestone pore microscopic images of different zoom scales, the scale-independence is proved to be possessed by complexity of pore, which indicates that the limestone is a good fractal body, and its complexity can be studied by means of fractal dimension.

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Ma, Shengchao, Zhenzhong Zhang, Kaiyue Shen, Xuedong He, Jun Li, Huaqiang Yin, Xingtuan Yang e Shengyao Jiang. "Study on 3D Pore Characteristics of Carbon Materials in HTGR by Micro-CT and HPMI Methods". Science and Technology of Nuclear Installations 2019 (2 maggio 2019): 1–10. http://dx.doi.org/10.1155/2019/5751463.

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Many tons of porous carbon materials (including BC and IG-110) are contained in HTGR, which are serving as structural material and fuel matrix material. These materials would absorb moisture and other impurities when exposed to the environment, and these impurities (especially moisture) absorbed in the carbon material must be removed before the reactor operation to prevent corrosion reaction at high temperature (more than 500°C). As the pore microscopic structure characteristic is the significant factor affecting the gas adsorption and flow in the porous materials, the detailed 3D pore structures of the carbon materials (BC and IG-110) in HTGR were studied by Micro-XCT and HPMI methods in this paper. These pore structure characteristics include pore geometry, pore size distribution, and pore throat connectivity. The test results show that the pore size distribution of BC material is wide, and the pore diameter is obviously larger than that of IG-110. Pore connections in BC show radial shape connections at some special points, and the pore connectivity in IG-110 is very complex and presents a huge complex 3D pore network.

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Ye, Dayu, Guannan Liu, Ning Luo, Feng Gao, Xinmin Zhu e Fengtian Yue. "Quantitative Analysis of the Topological Structure of Rock Pore Network". Geofluids 2021 (13 giugno 2021): 1–11. http://dx.doi.org/10.1155/2021/5517489.

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As the most significant nonlinear reservoir, the rocks have complex structural characteristic. The pore structure of the rock is varied in shape and complex in connectivity. However, the prevailing methods for characterising the microstructure of rocks, such as the coordination number method and fractal theory, are still difficult to quantify the structural properties. In this study, based on the CT-scan method and a new complex network theory, the topological characteristics of rocks such as seepage path selection, degree of pore aggregation, pore importance, and pore module structure are analysed. The results show that the scale-free network model is more reliable in characterising the rock pore network than previously published structural models, and a small number of pores are the “key” to the seepage process. Besides, we proposed a new method to quantify the importance of rock pores and present the distribution characteristics and connectivity laws of the rock-pore network. This provides a new method to study the seepage process of the nonlinear reservoirs.

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Cronshaw, Janet M., Andrew N. Krutchinsky, Wenzhu Zhang, Brian T. Chait e Michael J. Matunis. "Proteomic analysis of the mammalian nuclear pore complex". Journal of Cell Biology 158, n. 5 (26 agosto 2002): 915–27. http://dx.doi.org/10.1083/jcb.200206106.

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As the sole site of nucleocytoplasmic transport, the nuclear pore complex (NPC) has a vital cellular role. Nonetheless, much remains to be learned about many fundamental aspects of NPC function. To further understand the structure and function of the mammalian NPC, we have completed a proteomic analysis to identify and classify all of its protein components. We used mass spectrometry to identify all proteins present in a biochemically purified NPC fraction. Based on previous characterization, sequence homology, and subcellular localization, 29 of these proteins were classified as nucleoporins, and a further 18 were classified as NPC-associated proteins. Among the 29 nucleoporins were six previously undiscovered nucleoporins and a novel family of WD repeat nucleoporins. One of these WD repeat nucleoporins is ALADIN, the gene mutated in triple-A (or Allgrove) syndrome. Our analysis defines the proteome of the mammalian NPC for the first time and paves the way for a more detailed characterization of NPC structure and function.

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Stroeven, Piet, e Zhanqi Guo. "MODERN ROUTES TO EXPLORE CONCRETE’S COMPLEX PORE SPACE". Image Analysis & Stereology 25, n. 2 (3 maggio 2011): 75. http://dx.doi.org/10.5566/ias.v25.p75-86.

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This paper concentrates on discrete element computer-simulation of concrete. It is argued on the basis of stochastic heterogeneity theory that modern concurrent-algorithm-based systems should be employed for the assessment of pore characteristics underlying durability performance of cementitious materials. The SPACE system was developed at Delft University of Technology for producing realistic schematizations of realcrete for a wide range of other particle packing problems, involving aggregate and fresh cement, and for the purpose of exploring characteristics in the hardened state of concrete, including of the pore network structure because of obvious durability problems. Since structure-sensitive properties are involved, schematization of reality should explicitly deal with the configuration of the cement particles in the fresh state. The paper concentrates on the stereological and mathematical morphology operations executed to acquire information on particle size, global porosity, and on distribution of porosity and of the connected pore fraction as a result of the near neighbourhood of aggregate grains. Goal is to provide information obtained along different exploration routes of concrete's pore space for setting up a pore network modelling approach. This type of methodological papers is scarce in concrete technology, if not missing at all. Technical publications that report on obtained results in our investigations are systematically referred to.

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Beck, Martin, e Joseph S. Glavy. "Toward understanding the structure of the vertebrate nuclear pore complex". Nucleus 5, n. 2 (marzo 2014): 119–23. http://dx.doi.org/10.4161/nucl.28739.

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Kim, Seung Joong, Javier Fernandez-Martinez, Ilona Nudelman, Yi Shi, Wenzhu Zhang, Barak Raveh, Thurston Herricks et al. "Integrative structure and functional anatomy of a nuclear pore complex". Nature 555, n. 7697 (marzo 2018): 475–82. http://dx.doi.org/10.1038/nature26003.

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Kelley, Kotaro, Kevin E. Knockenhauer, Greg Kabachinski e Thomas U. Schwartz. "Atomic structure of the Y complex of the nuclear pore". Nature Structural & Molecular Biology 22, n. 5 (30 marzo 2015): 425–31. http://dx.doi.org/10.1038/nsmb.2998.

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Noack, Johannes, Katharina Teinz, Christian Schaumberg, Carsten Fritz, Stephan Rüdiger e Erhard Kemnitz. "Metal fluoride materials with complex pore structure and organic functionality". J. Mater. Chem. 21, n. 2 (2011): 334–38. http://dx.doi.org/10.1039/c0jm02204g.

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Kabachinski, G., e T. U. Schwartz. "The nuclear pore complex - structure and function at a glance". Journal of Cell Science 128, n. 3 (29 gennaio 2015): 423–29. http://dx.doi.org/10.1242/jcs.083246.

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Pante, N., e U. Aebi. "Exploring nuclear pore complex structure and function in molecular detail". Journal of Cell Science 1995, Supplement 19 (1 gennaio 1995): 1–11. http://dx.doi.org/10.1242/jcs.1995.supplement_19.1.

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Beck, M. "Nuclear Pore Complex Structure and Dynamics Revealed by Cryoelectron Tomography". Science 306, n. 5700 (19 novembre 2004): 1387–90. http://dx.doi.org/10.1126/science.1104808.

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Nudelman, I., S. J. Kim, J. Fernandez-Martinez, Y. Shi, W. Zhang, B. Raveh, T. Herricks et al. "Integrative Structure and Functional Anatomy of a Nuclear Pore Complex". Microscopy and Microanalysis 24, S1 (agosto 2018): 1212–13. http://dx.doi.org/10.1017/s1431927618006542.

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Panté, Nelly, Birthe Fahrenkrog e Ueli Aebi. "Molecular dissection of nuclear pore complex structure and nucleocytoplasmic transport". Biology of the Cell 90, n. 3 (giugno 1998): 275–76. http://dx.doi.org/10.1016/s0248-4900(98)80037-3.

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Starr, Christopher M., e John A. Hanover. "Structure and function of the nuclear pore complex: New perspectives". BioEssays 12, n. 7 (luglio 1990): 323–30. http://dx.doi.org/10.1002/bies.950120704.

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Lim, Roderick Y. H., Ueli Aebi e Birthe Fahrenkrog. "Towards reconciling structure and function in the nuclear pore complex". Histochemistry and Cell Biology 129, n. 2 (29 gennaio 2008): 105–16. http://dx.doi.org/10.1007/s00418-007-0371-x.

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Field, Mark C., e Michael P. Rout. "Pore timing: the evolutionary origins of the nucleus and nuclear pore complex". F1000Research 8 (3 aprile 2019): 369. http://dx.doi.org/10.12688/f1000research.16402.1.

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Abstract (sommario):

The name “eukaryote” is derived from Greek, meaning “true kernel”, and describes the domain of organisms whose cells have a nucleus. The nucleus is thus the defining feature of eukaryotes and distinguishes them from prokaryotes (Archaea and Bacteria), whose cells lack nuclei. Despite this, we discuss the intriguing possibility that organisms on the path from the first eukaryotic common ancestor to the last common ancestor of all eukaryotes did not possess a nucleus at all—at least not in a form we would recognize today—and that the nucleus in fact arrived relatively late in the evolution of eukaryotes. The clues to this alternative evolutionary path lie, most of all, in recent discoveries concerning the structure of the nuclear pore complex. We discuss the evidence for such a possibility and how this impacts our views of eukaryote origins and how eukaryotes have diversified subsequent to their last common ancestor.

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Fernandez-Martinez, Javier, Jeremy Phillips, Matthew D. Sekedat, Ruben Diaz-Avalos, Javier Velazquez-Muriel, Josef D. Franke, Rosemary Williams et al. "Structure–function mapping of a heptameric module in the nuclear pore complex". Journal of Cell Biology 196, n. 4 (13 febbraio 2012): 419–34. http://dx.doi.org/10.1083/jcb.201109008.

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The nuclear pore complex (NPC) is a multiprotein assembly that serves as the sole mediator of nucleocytoplasmic exchange in eukaryotic cells. In this paper, we use an integrative approach to determine the structure of an essential component of the yeast NPC, the ∼600-kD heptameric Nup84 complex, to a precision of ∼1.5 nm. The configuration of the subunit structures was determined by satisfaction of spatial restraints derived from a diverse set of negative-stain electron microscopy and protein domain–mapping data. Phenotypic data were mapped onto the complex, allowing us to identify regions that stabilize the NPC’s interaction with the nuclear envelope membrane and connect the complex to the rest of the NPC. Our data allow us to suggest how the Nup84 complex is assembled into the NPC and propose a scenario for the evolution of the Nup84 complex through a series of gene duplication and loss events. This work demonstrates that integrative approaches based on low-resolution data of sufficient quality can generate functionally informative structures at intermediate resolution.

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Zhang, Hong, Zhengchen Zhang, Zhenlin Wang, Yamin Wang, Rui Yang, Tao Zhu, Feifei Luo e Kouqi Liu. "Using Fractal Theory to Study the Influence of Movable Oil on the Pore Structure of Different Types of Shale: A Case Study of the Fengcheng Formation Shale in Well X of Mahu Sag, Junggar Basin, China". Fractal and Fractional 8, n. 4 (20 aprile 2024): 242. http://dx.doi.org/10.3390/fractalfract8040242.

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This study investigated the influence of movable oil on the pore structure of various shale types, analyzing 19 shale samples from Well X in the Mahu Sag of the Junggar Basin. Initially, X-ray diffraction (XRD) analysis classified the shale samples. Subsequently, the geochemical properties and pore structures of the samples, both pre and post oil Soxhlet extraction, were comparatively analyzed through Total Organic Carbon (TOC) content measurement, Rock-Eval pyrolysis, and nitrogen adsorption experiments. Additionally, fractal theory quantitatively described the impact of movable oil on the pore structure of different shale types. Results indicated higher movable oil content in siliceous shale compared to calcareous shale. Oil extraction led to a significant increase in specific surface area and pore volume in all samples, particularly in siliceous shale. Calcareous shale predominantly displays H2–H3 type hysteresis loops, indicating a uniform pore structure with ink-bottle-shaped pores. Conversely, siliceous shale exhibited diverse hysteresis loops, reflecting its complex pore structure. The fractal dimension in calcareous shale correlated primarily with pore structure, exhibiting no significant correlation with TOC content before or after oil extraction. Conversely, the fractal dimension changes in siliceous shale samples do not have a clear correlation with either TOC content or pore structure, suggesting variations may result from both TOC and pore structure.

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Gao, Feng, Yuhao Hu, Guannan Liu e Yugui Yang. "Experiment Study on Topological Characteristics of Sandstone Coating by Micro CT". Coatings 10, n. 12 (24 novembre 2020): 1143. http://dx.doi.org/10.3390/coatings10121143.

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The pore structure is an important factor of tunnel coating failure, cracking and water leakage. Some investigations on the statistical law of pores and pore networks have been conducted, but little quantitative analysis is observed on topology structure of the pore network, and even the pore structure of sandstone is complex and cross-scale distributed. Therefore, it is of theoretical and engineering significance to quantitatively characterize the connectivity of the pore network in sandstone. This study proposes a new complex network theory to analyze the three-dimensional nature of pore network structure in sandstone. The topological network structure, such as clustering degree, average path length and the module, which cannot be analyzed by traditional coordination number and fractal dimension methods, is analyzed. Numerical simulation results show that a scale-free network model is more suitable for describing the sandstone pore network than random models. The pore network of sandstone has good uniformity. The connectivity of sandstone pore networks has great potential for permeability enhancement. Therefore, this new method provides a way to deeply understand the pore connectivity characteristics of sandstone and to explore the distribution of crack grids in the arch of tunnel coatings.

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Hu, Yuhao, Guannan Liu, Feng Gao, Fengtian Yue e Tao Gao. "A Complex Network Approach for Quantitative Characterization and Robustness Analysis of Sandstone Pore Network Structure". Geofluids 2021 (6 aprile 2021): 1–10. http://dx.doi.org/10.1155/2021/6671829.

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The rational characterization and quantitative analysis of the complex internal pore structure of rock is the foundation to solve many underground engineering problems. In this paper, CT imaging technology is used to directly characterize the three-dimensional pore network topology of sandstone with different porosity. Then, in view of the problem, which is difficult to quantify the detailed topological structure of the sandstone pore networks in the previous study, the new complex network theory is used to characterize the pore structure. PageRank algorithm is based on the number of connections between targets as a measure index to rank the targets, so the network degree distribution, average path length, clustering coefficient, and robustness based on PageRank algorithm and permeability-related topological parameters are studied. The research shows that the degree distribution of sandstone pore network satisfies power law distribution, and it can be characterized by scale-free network model. The permeability of rock is inversely proportional to the average path length of sandstone network. The sandstone pore network has strong robustness to random disturbance, while a small number of pores with special topological properties play a key role in the macroscopic permeability of sandstone. This study attempts to provide a new perspective of quantifying the microstructure of the pore network of sandstone and revealing the microscopic structure mechanism of macroscopic permeability of pore rocks.

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Ming, Yang, e Lin Mian. "A Novel Method for Analyzing Pore Size Distribution of Complex Geometry Shaped Porous Shale". Materials Science Forum 1003 (luglio 2020): 134–43. http://dx.doi.org/10.4028/www.scientific.net/msf.1003.134.

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This article proposes the differential BJH equation based on the principles of multilayer adsorption and capillary condensation, which was simplified by theoretical investigation and experiments. This work indicates that the differential function of isotherm and the differential function of pore size to relative pressure determine the pore size distribution of porous media. The differential BJH model can be used to explain the source of the false peak in pore size distribution and to calculate the pore size distribution of different shapes of pores in a porous media with a porous structure. It has an excellent application prospect in the characterization of complex pore structure represented by shale.

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Defrenne, Yves, Vasili Zhdankin, Sahana Ramanna, Shri Ramaswamy e Bandaru Ramarao. "Three-dimensional pore structure visualization and characterization of paper using X-ray computed tomography". September 2017 16, n. 09 (2017): 519–30. http://dx.doi.org/10.32964/tj16.9.519.

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Porous biomaterials such as paper and board have a complex structure that influences their mechanical, optical, and transport properties and thereby their performance during manufacturing and end uses. Reconstruction of the three-dimensional (3D) pore spaces in paper was obtained by X-ray computed tomography and used to study the structure and its impact on properties. A set of laboratory-made paper samples of varying freeness was prepared, and the 3D structures of the samples were visualized and characterized. Tomographic reconstruction images were processed using techniques such as anisotropic diffusion, minimum error thresholding, and isolated voxel removal to enhance image quality. The pore structures were analyzed to determine porosity, fiber-pore interfacial surface area, geometric tortuosity, and pore size distributions (using a sphere growing algorithm). These properties were compared with experimental data and were found to be in good agreement. The results from 3D visualization and characterization were then compared with experimental data of various samples using conventional pore structure characterization techniques, such as mercury intrusion porosimetry.

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Debler, Erik W., Kuo-Chiang Hsia, Vivien Nagy, Hyuk-Soo Seo e André Hoelz. "Characterization of the membrane-coating Nup84 complex: Paradigm for the nuclear pore complex structure". Nucleus 1, n. 2 (1 marzo 2010): 150–57. http://dx.doi.org/10.4161/nucl.1.2.11120.

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Zhang, Mei Ling, Jia Yu You e Yun Xin Liu. "Impact Analysis of Complex Pore Structure Parameters on Degree of Flooding Formation". Applied Mechanics and Materials 543-547 (marzo 2014): 4141–44. http://dx.doi.org/10.4028/www.scientific.net/amm.543-547.4141.

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It can be seen from the correspondence consists of three porosity curves of reservoir and cores capillary pressure curves that, the larger pore connectivity a rock has, the higher movable fluid saturation calculation will be under natural pressure. If the restraint porosity is higher, even in the presence of fluid in the formation applied pressure, formation fluid is still harder to drive out.It can be proved by instance of well cores pressure mercury data. By establishing relationships between data of dynamic mining degree and the averagr radius of pore throat shows thatunder the same mining time, the moisture content of formations with high averagr radius of pore throat is higher than that with low valuse.

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