Artykuły w czasopismach: „Fluid mosaic model”

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Jacobson, K., E. Sheets i R. Simson. "Revisiting the fluid mosaic model of membranes". Science 268, nr 5216 (9.06.1995): 1441–42. http://dx.doi.org/10.1126/science.7770769.

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Fromherz, Peter. "Spatio-temporal patterns in the fluid-mosaic model of membranes". Biochimica et Biophysica Acta (BBA) - Biomembranes 944, nr 1 (wrzesień 1988): 108–11. http://dx.doi.org/10.1016/0005-2736(88)90323-9.

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Forslind, B. "A domain mosaic model of the skin barrier." Acta Dermato-Venereologica 74, nr 1 (1.01.1994): 1–6. http://dx.doi.org/10.2340/00015555741214.

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The skin barrier primarily protects the body against uncontrolled loss of water and in addition prevents water and matter of the environment from indiscriminately entering the living system. The current concept of the skin barrier suggests that permeability is governed by a hydrophilic and a hydrophobic "channel". To account both for the barrier function and the hydrophilic and hydrophobic pathways through this barrier, we propose a new model, "the domain mosaic model of the skin barrier", which depicts the bulk of the lipids as segregated into crystalline/gel domains bordered by "grain borders" where lipids are in the fluid crystalline state. Such an arrangement provides for an effective "water-tight" barrier that allows a minute and controlled loss of water to keep the corneocytes moistened. In addition the model provides for the necessary mechanical properties permitting bending and stress imposed on the skin surface. Furthermore, the fluid character of the "grain borders" represents areas where lipid and hydrophobic molecules may diffuse through the system on down-hill gradients. It is suggested that in the border areas between the crystalline domains, structural transformations of the lipid organization due to permeation promoters may take place without structural changes in the bulk organization of lipids in the crystalline or gel phase.

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Zhang, Jianbing, Bingwen Jing, Nobuya Tokutake i Steven L. Regen. "Transbilayer Complementarity of Phospholipids. A Look beyond the Fluid Mosaic Model". Journal of the American Chemical Society 126, nr 35 (wrzesień 2004): 10856–57. http://dx.doi.org/10.1021/ja046892a.

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Nicolson, Garth L., i Gonzalo Ferreira de Mattos. "Fifty Years of the Fluid–Mosaic Model of Biomembrane Structure and Organization and Its Importance in Biomedicine with Particular Emphasis on Membrane Lipid Replacement". Biomedicines 10, nr 7 (15.07.2022): 1711. http://dx.doi.org/10.3390/biomedicines10071711.

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The Fluid–Mosaic Model has been the accepted general or basic model for biomembrane structure and organization for the last 50 years. In order to establish a basic model for biomembranes, some general principles had to be established, such as thermodynamic assumptions, various molecular interactions, component dynamics, macromolecular organization and other features. Previous researchers placed most membrane proteins on the exterior and interior surfaces of lipid bilayers to form trimolecular structures or as lipoprotein units arranged as modular sheets. Such membrane models were structurally and thermodynamically unsound and did not allow independent lipid and protein lateral movements. The Fluid–Mosaic Membrane Model was the only model that accounted for these and other characteristics, such as membrane asymmetry, variable lateral movements of membrane components, cis- and transmembrane linkages and dynamic associations of membrane components into multimolecular complexes. The original version of the Fluid–Mosaic Membrane Model was never proposed as the ultimate molecular description of all biomembranes, but it did provide a basic framework for nanometer-scale biomembrane organization and dynamics. Because this model was based on available 1960s-era data, it could not explain all of the properties of various biomembranes discovered in subsequent years. However, the fundamental organizational and dynamic aspects of this model remain relevant to this day. After the first generation of this model was published, additional data on various structures associated with membranes were included, resulting in the addition of membrane-associated cytoskeletal, extracellular matrix and other structures, specialized lipid–lipid and lipid–protein domains, and other configurations that can affect membrane dynamics. The presence of such specialized membrane domains has significantly reduced the extent of the fluid lipid membrane matrix as first proposed, and biomembranes are now considered to be less fluid and more mosaic with some fluid areas, rather than a fluid matrix with predominantly mobile components. However, the fluid–lipid matrix regions remain very important in biomembranes, especially those involved in the binding and release of membrane lipid vesicles and the uptake of various nutrients. Membrane phospholipids can associate spontaneously to form lipid structures and vesicles that can fuse with various cellular membranes to transport lipids and other nutrients into cells and organelles and expel damaged lipids and toxic hydrophobic molecules from cells and tissues. This process and the clinical use of membrane phospholipid supplements has important implications for chronic illnesses and the support of healthy mitochondria, plasma membranes and other cellular membrane structures.

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Ohki, Kazuo. "A quarter of century since the proposal of the fluid mosaic membrane model." membrane 21, nr 4 (1996): 220–22. http://dx.doi.org/10.5360/membrane.21.220.

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Zhang, Anan, Gaoqiang Peng, Wei Yang, Guanglong Qu i Huang Huang. "Risk Assessment of Offshore Micro Integrated Energy System Based on Fluid Mosaic Model". IEEE Access 8 (2020): 76715–25. http://dx.doi.org/10.1109/access.2020.2989508.

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Catalá, Angel. "Lipid peroxidation modifies the picture of membranes from the “Fluid Mosaic Model” to the “Lipid Whisker Model”". Biochimie 94, nr 1 (styczeń 2012): 101–9. http://dx.doi.org/10.1016/j.biochi.2011.09.025.

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Morange, Michel. "What history tells us XXX. The emergence of the fluid mosaic model of membranes". Journal of Biosciences 38, nr 1 (22.01.2013): 3–7. http://dx.doi.org/10.1007/s12038-013-9301-3.

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Fromherz, Peter. "Dissipative Structures of Ion Channels in the Fluid Mosaic Model of a Membrane Cable". Berichte der Bunsengesellschaft für physikalische Chemie 92, nr 9 (wrzesień 1988): 1010–16. http://dx.doi.org/10.1002/bbpc.198800252.

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Nicolson, Garth L., i Gonzalo Ferreira de Mattos. "A Brief Introduction to Some Aspects of the Fluid–Mosaic Model of Cell Membrane Structure and Its Importance in Membrane Lipid Replacement". Membranes 11, nr 12 (29.11.2021): 947. http://dx.doi.org/10.3390/membranes11120947.

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Early cell membrane models placed most proteins external to lipid bilayers in trimolecular structures or as modular lipoprotein units. These thermodynamically untenable structures did not allow lipid lateral movements independent of membrane proteins. The Fluid–Mosaic Membrane Model accounted for these and other properties, such as membrane asymmetry, variable lateral mobilities of membrane components and their associations with dynamic complexes. Integral membrane proteins can transform into globular structures that are intercalated to various degrees into a heterogeneous lipid bilayer matrix. This simplified version of cell membrane structure was never proposed as the ultimate biomembrane description, but it provided a basic nanometer scale framework for membrane organization. Subsequently, the structures associated with membranes were considered, including peripheral membrane proteins, and cytoskeletal and extracellular matrix components that restricted lateral mobility. In addition, lipid–lipid and lipid–protein membrane domains, essential for cellular signaling, were proposed and eventually discovered. The presence of specialized membrane domains significantly reduced the extent of the fluid lipid matrix, so membranes have become more mosaic with some fluid areas over time. However, the fluid regions of membranes are very important in lipid transport and exchange. Various lipid globules, droplets, vesicles and other membranes can fuse to incorporate new lipids or expel damaged lipids from membranes, or they can be internalized in endosomes that eventually fuse with other internal vesicles and membranes. They can also be externalized in a reverse process and released as extracellular vesicles and exosomes. In this Special Issue, the use of membrane phospholipids to modify cellular membranes in order to modulate clinically relevant host properties is considered.

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Olsen, O. H., i P. S. Lomdahl. "Influence of stochastic noise on self-organized patterns in a fluid-mosaic model of membranes". Physics Letters A 165, nr 2 (maj 1992): 133–42. http://dx.doi.org/10.1016/0375-9601(92)90088-4.

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Bozdaganyan, M. E., i K. V. Shaitan. "INVESTIGATION OF STRUCTURE OF THE MEMBRANE RAFTS BY MEANS OF COMPUTER MODELING". Journal of Clinical Practice 7, nr 4 (15.12.2016): 66–72. http://dx.doi.org/10.17816/clinpract7466-72.

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Understanding the structure of the biological membrane and its role in the cell has evolved significantly since the introduction of the classical fluid mosaic model by Singer and Nicholson. Later fluid mosaic model has been redesigned, expanded and has become considerably complicated. It has been experimentally proved that the membrane consists of so-called rafts, which are functional “islands” with the specific lipid composition with proteins. Lipid rafts play a central role in many cellular processes, including barrier functions, membrane polarization and the cell signaling. Several groups of pathogens, bacteria, prions, viruses, parasites use lipid rafts for their purposes. Rafts always occur on both sides of the membrane opposite to each other, but the nature of the two-layer rafts are still poorly understood. Previously it was theoretically calculated that the shift of the monolayers in raft occurs, which reduces the mechanical energy of the boundaries, and ultimately leads to a bilayer structure of the raft. In this study with the help of computer modeling we study the energy of interaction between two monolayers of the raft in order to test the hypothesis about their relative shift.

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Glazov, Konstantin, Galina Trebeleva, Ivan Abornev, Andrey Kizilov, Vladlen Yurkov i Gleb Yurkov. "Reconstruction and Visualization of the Mosaic Floor of the Temple of Pitiunt Hillfort". Applied Sciences 13, nr 10 (18.05.2023): 6210. http://dx.doi.org/10.3390/app13106210.

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The 3D reconstruction of the Great Pitiunt Fortress has been our long-term goal. The results of archaeological excavations have revealed traces of a mosaic floor in one of the temples. It was impossible to carry out a full reconstruction of the temple without first restoring the mosaic floor. The area of the preserved mosaic found during the excavations was only 33 square meters. This is 10.5% of the total interior area of the temple of 317 square meters. However, based on a number of reasons, i.e., the direction of the dividing borders between the elements of the mosaic, the requirement of symmetry of individual sections, the adjustment of motifs and the analysis of similar contemporaneous sites, it was possible to make a version of the general view of the reconstructed mosaic floor for further processing in the 3D reconstruction of the temples of the complex. This article provides the methods described, an analysis and justification of the reconstructed design of the mosaic in fragments and a holistic final model. The stylistic features of the mosaic have been identified, and the reasons for the dating of the mosaic have been given.

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Suzuki, Kenichi G. N., i Akihiro Kusumi. "Refinement of Singer-Nicolson fluid-mosaic model by microscopy imaging: Lipid rafts and actin-induced membrane compartmentalization". Biochimica et Biophysica Acta (BBA) - Biomembranes 1865, nr 2 (luty 2023): 184093. http://dx.doi.org/10.1016/j.bbamem.2022.184093.

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Helenius, Ari. "Membranes, viruses, detergents, and endosomes". Molecular Biology of the Cell 23, nr 21 (listopad 2012): 4157–59. http://dx.doi.org/10.1091/mbc.e12-05-0383.

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The fluid mosaic model for biological membranes was formulated 40 years ago. Ten years later endosomes were discovered as important prelysosomal organelles. At the outset of my research career, I was fortunate to witness both these turning points in biochemistry and cell biology from close up, and to participate in some of the studies. In this short essay, I will describe how this came about, and also try to provide some background as to the general starting situation in those not so distant pioneering years of membrane biology.

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Byrum, Jennifer N., i William Rodgers. "Membrane–cytoskeleton interactions in cholesterol-dependent domain formation". Essays in Biochemistry 57 (6.02.2015): 177–87. http://dx.doi.org/10.1042/bse0570177.

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Since the inception of the fluid mosaic model, cell membranes have come to be recognized as heterogeneous structures composed of discrete protein and lipid domains of various dimensions and biological functions. The structural and biological properties of membrane domains are represented by CDM (cholesterol-dependent membrane) domains, frequently referred to as membrane ‘rafts’. Biological functions attributed to CDMs include signal transduction. In T-cells, CDMs function in the regulation of the Src family kinase Lck (p56lck) by sequestering Lck from its activator CD45. Despite evidence of discrete CDM domains with specific functions, the mechanism by which they form and are maintained within a fluid and dynamic lipid bilayer is not completely understood. In the present chapter, we discuss recent advances showing that the actomyosin cytoskeleton has an integral role in the formation of CDM domains. Using Lck as a model, we also discuss recent findings regarding cytoskeleton-dependent CDM domain functions in protein regulation.

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Murray, Samuel M, Richard A O'Brien, Kaila M Mattson, Christopher Ceccarelli, Richard E Sykora, Kevin N West i James H Davis. "The Fluid-Mosaic Model, Homeoviscous Adaptation, and Ionic Liquids: Dramatic Lowering of the Melting Point by Side-Chain Unsaturation". Angewandte Chemie International Edition 49, nr 15 (8.03.2010): 2755–58. http://dx.doi.org/10.1002/anie.200906169.

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Murray, Samuel M, Richard A O'Brien, Kaila M Mattson, Christopher Ceccarelli, Richard E Sykora, Kevin N West i James H Davis. "The Fluid-Mosaic Model, Homeoviscous Adaptation, and Ionic Liquids: Dramatic Lowering of the Melting Point by Side-Chain Unsaturation". Angewandte Chemie 122, nr 15 (8.03.2010): 2815–18. http://dx.doi.org/10.1002/ange.200906169.

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Karkoulias, Dionysios G., Evangelos D. Tzoganis, Anastasios G. Panagiotopoulos, Spyridon-Giaroslav D. Acheimastos i Dionissios P. Margaris. "Computational Fluid Dynamics Study of Wing in Air Flow and Air–Solid Flow Using Three Different Meshing Techniques and Comparison with Experimental Results in Wind Tunnel". Computation 10, nr 3 (23.02.2022): 34. http://dx.doi.org/10.3390/computation10030034.

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The main purpose of this work is to simulate the flow of air and solid particles over a wildfire and to investigate the single and multiphase flow over the surface of a custom-designed wing with an Eppler-420 airfoil including an appendant custom-designed blended winglet. The wing is the result of a conceptual and preliminary design of a small-scale unmanned aerial vehicle (UAV) designed to assist in firefighting. The fire embers will be simulated in the Ansys Fluent commercial code as solid particles injected in the continuous phase, in an Euler–Lagrange approach. Primarily studied were the response of the model in air and air–solid flows, as well as the impact on aerodynamic efficiency due to the existence of the second phase. Moreover, the effects of unstructured, structured and mosaic poly-hexcore meshes are investigated and compared. The computational fluid dynamics (CFD) simulations, were implemented using a pressure-based solver, spatial discretization was conducted with a second-order upwind scheme, and the k-omega SST (k-ω SST) turbulence model was applied. Meanwhile, the two-phase flow was simulated using the Discrete Phase Model with reflect boundary condition on the surface of the wing and two-way coupling between continuous and discrete phase. To validate the results, experiments were conducted in a subsonic wind tunnel using a 3D printed model of the wing. The results show good agreement between simulations and experiments, with the structured mesh coming closer to reality, followed by the mosaic and unstructured meshes, respectively. Finally, a reduction in the aerodynamic efficiency of the wing section is observed, due to the presence of solid particles.

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Arocena, Virgel M., i Louis Angelo M. Danao. "Improving the Modeling of Pressure Pulsation and Cavitation Prediction in a Double-Volute Double-Suction Pump Using Mosaic Meshing Technology". Processes 11, nr 3 (22.02.2023): 660. http://dx.doi.org/10.3390/pr11030660.

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Over the years, Computational Fluid Dynamics (CFD) has been an integral part of most pump design processes. Unfortunately, as calculation schemes and flow investigations become more complicated, the cost of conducting numerical simulations also becomes more expensive in terms of computational time. To remedy this, cutting-edge technology, together with novel calculation techniques, are continuously introduced with the end target of producing more accurate results and faster computing time. In this paper, CFD simulations are run on a numerical model of a double-volute double-suction pump prepared using ANSYS Fluent Mosaic meshing technology. Poly-Hexcore, the first application of Mosaic technology, fills the bulk region with octree hexes, keeps a high-quality layered poly-prism mesh in the boundary layer, and conformally connects these two meshes with general polyhedral elements. This technology promises to provide a lower number of cells along with a significant increase in computing speed. In this paper, steady state results of the model with Mosaic Poly-Hexcore mesh with ~37% fewer cells produced comparable results with a similarly sized model prepared with multi-block structured hexagonal mesh. The predicted pump head, efficiency and shaft power under the design conditions were within 1% for both models, while calculation time was reduced by ~25%. Additional simulations using the Poly-Hexcore mesh showed that the model was able to closely predict the pump’s NPSH3 for 0.8QD, 1.0QD, and 1.2QD compared with the manufacturer’s data. Under cavitating flow conditions, the formation of vapor bubbles was observed on the suction side, starting at the leading edge of the blade and slowly forming as thin sheets towards the trailing edge as the suction pressure is reduced. Lastly, pressure fluctuations were observed from pressure coefficient data collected at several monitoring points in the volute and the impeller. It was seen that due to the interaction between the stationary casing and the rotating impeller, pulsations were equivalent to the blade passing frequency and its harmonics.

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Whang, Allen Jong-Woei, Yi-Yung Chen, Tsai-Hsien Yang, Cheng-Tse Lin, Zhi-Jia Jian i Chun-Han Chou. "Zernike Coefficient Prediction Technique for Interference Based on Generation Adversarial Network". Applied Sciences 11, nr 15 (28.07.2021): 6933. http://dx.doi.org/10.3390/app11156933.

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In the paper, we propose a novel prediction technique to predict Zernike coefficients from interference fringes based on Generative Adversarial Network (GAN). In general, the task of GAN is image-to-image translation, but we design GAN for image-to-number translation. In the GAN model, the Generator’s input is the interference fringe image, and its output is a mosaic image. Moreover, each piece of the mosaic image links to the number of Zernike coefficients. Root Mean Square Error (RMSE) is our criterion for quantifying the ground truth and prediction coefficients. After training the GAN model, we use two different methods: the formula (ideal images) and optics simulation (simulated images) to estimate the GAN model. As a result, the RMSE is about 0.0182 ± 0.0035λ with the ideal image case and the RMSE is about 0.101 ± 0.0263λ with the simulated image case. Since the outcome in the simulated image case is poor, we use the transfer learning method to improve the RMSE to about 0.0586 ± 0.0035λ. The prediction technique applies not only to the ideal case but also to the actual interferometer. In addition, the novel prediction technique makes predicting Zernike coefficients more accurate than our previous research.

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Lee, Changno, i Jaehong Oh. "Sensor-Level Mosaic of Multistrip KOMPSAT-3 Level 1R Products". Applied Sciences 11, nr 15 (23.07.2021): 6796. http://dx.doi.org/10.3390/app11156796.

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High-resolution satellite images such as KOMPSAT-3 data provide detailed geospatial information over interest areas that are evenly located in an inaccessible area. The high-resolution satellite cameras are designed with a long focal length and a narrow field of view to increase spatial resolution. Thus, images show relatively narrow swath widths (10–15 km) compared to dozens or hundreds of kilometers in mid-/low-resolution satellite data. Therefore, users often face obstacles to orthorectify and mosaic a bundle of delivered images to create a complete image map. With a single mosaicked image at the sensor level delivered only with radiometric correction, users can process and manage simplified data more efficiently. Thus, we propose sensor-level mosaicking to generate a seamless image product with geometric accuracy to meet mapping requirements. Among adjacent image data with some overlaps, one image is the reference, whereas the others are projected using the sensor model information with shuttle radar topography mission. In the overlapped area, the geometric discrepancy between the data is modeled in spline along the image line based on image matching with outlier removals. The new sensor model information for the mosaicked image is generated by extending that of the reference image. Three strips of KOMPSAT-3 data were tested for the experiment. The data showed that irregular image discrepancies between the adjacent data were observed along the image line. This indicated that the proposed method successfully identified and removed these discrepancies. Additionally, sensor modeling information of the resulted mosaic could be improved by using the averaging effects of input data.

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Wu, Yu-Ting, Zhen Qin, Amre Eizad i Sung-Ki Lyu. "Design and Numerical Simulation-Based Optimization of a Novel Flat-Face Coupling System for Hydraulic Power Equipment". Applied Sciences 11, nr 1 (3.01.2021): 388. http://dx.doi.org/10.3390/app11010388.

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Coupling systems play a vital role in hydraulic power transmission equipment. In recent years, flat-face coupling systems have been extensively studied due to their environment friendly features. The difficulty of the connection process of hydraulic equipment increases with the increase in their working pressure. To improve the convenience of making high-pressure connections, a novel flat-face coupling system is proposed in this article. In the proposed design, which is based on the conventional flat-face coupling system, the resistance caused by high hydraulic fluid pressure during coupling is drastically reduced by the addition of an instantaneous pressure relief module. In this study, the theoretical model of the system kinetics is established to illustrate the operational mechanism of the novel design, and a series of computational fluid dynamics numerical investigations based on the novel dynamic mesh technology and Ansys Mosaic meshing technology are implemented to verify the rationality of the proposed design. Additionally, an optimal design of the novel flat-face coupling system is proposed to reduce the energy loss during hydraulic power transmission.

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Kusumi, Akihiro, Takahiro K. Fujiwara, Rahul Chadda, Min Xie, Taka A. Tsunoyama, Ziya Kalay, Rinshi S. Kasai i Kenichi G. N. Suzuki. "Dynamic Organizing Principles of the Plasma Membrane that Regulate Signal Transduction: Commemorating the Fortieth Anniversary of Singer and Nicolson's Fluid-Mosaic Model". Annual Review of Cell and Developmental Biology 28, nr 1 (10.11.2012): 215–50. http://dx.doi.org/10.1146/annurev-cellbio-100809-151736.

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Hill, Reghan J., i Chih-Ying Wang. "Diffusion in phospholipid bilayer membranes: dual-leaflet dynamics and the roles of tracer–leaflet and inter-leaflet coupling". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 470, nr 2167 (8.07.2014): 20130843. http://dx.doi.org/10.1098/rspa.2013.0843.

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A variety of observations—sometimes controversial—have been made in recent decades when attempting to elucidate the roles of interfacial slip on tracer diffusion in phospholipid membranes. Evans–Sackmann theory (1988) has furnished membrane viscosities and lubrication-film thicknesses for supported membranes from experimentally measured lateral diffusion coefficients. Similar to the Saffman and Delbrück model, which is the well-known counterpart for freely supported membranes, the bilayer is modelled as a single two-dimensional fluid. However, the Evans–Sackman model cannot interpret the mobilities of monotopic tracers, such as individual lipids or rigidly bound lipid assemblies; neither does it account for tracer–leaflet and inter-leaflet slip. To address these limitations, we solve the model of Wang and Hill, in which two leaflets of a bilayer membrane, a circular tracer and supports are coupled by interfacial friction, using phenomenological friction/slip coefficients. This furnishes an exact solution that can be readily adopted to interpret the mobilities of a variety of mosaic elements—including lipids, integral monotopic and polytopic proteins, and lipid rafts—in supported bilayer membranes.

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Nicolson, Garth L. "The Fluid—Mosaic Model of Membrane Structure: Still relevant to understanding the structure, function and dynamics of biological membranes after more than 40years". Biochimica et Biophysica Acta (BBA) - Biomembranes 1838, nr 6 (czerwiec 2014): 1451–66. http://dx.doi.org/10.1016/j.bbamem.2013.10.019.

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Marín-Buzón, Carmen, Antonio Miguel Pérez-Romero, Manuel J. León-Bonillo, Rubén Martínez-Álvarez, Juan Carlos Mejías-García i Francisco Manzano-Agugliaro. "Photogrammetry (SfM) vs. Terrestrial Laser Scanning (TLS) for Archaeological Excavations: Mosaic of Cantillana (Spain) as a Case Study". Applied Sciences 11, nr 24 (16.12.2021): 11994. http://dx.doi.org/10.3390/app112411994.

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The discovery of a Roman mosaic from the 2nd century AD in Cantillana (Seville) generated interest and the need for exhaustive documentation, so that it could be recreated with real measurements in a 3D model, not only to obtain an exact replica, but with the intention of analyzing and studying the behavior of two main geomatics techniques. Thus, the objective of this study was the comparative analysis of both techniques: near object photogrammetry by SfM and terrestrial laser scanner or TLS. The aim of this comparison was to assess the use of both techniques in archaeological excavations. Special attention was paid to the accuracy and precision of measurements and models, especially in altimetry. Mosaics are frequently relocated from their original location to be exhibited in museums or for restoration work, after which they are returned to their original place. Therefore, the altimetric situation is of special relevance. To analyze the accuracy and errors of each technique, a total station was used to establish the real values of the ground control points (GCP) on which the comparisons of both methods were to be made. It can be concluded that the SfM technique was the most accurate and least limiting for use in semi-buried archaeological excavations. This manuscript opens new perspectives for the use of SfM-based photogrammetry in archaeological excavations.

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Dong, Lei, Fangjian Liu, Mingchao Han i Hongjian You. "Mosaicing Technology for Airborne Wide Field-of-View Infrared Image". Applied Sciences 13, nr 15 (4.08.2023): 8977. http://dx.doi.org/10.3390/app13158977.

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Multi-detector parallel scanning is derived from the traditional airborne panorama camera, and it has a great lateral field of view. A wide field-of-view camera can be used to obtain an area of remote sensing image by whisk broom mood during the flight. The adjacent image during acquisition should cover the overlap region according to the flight path, and then the regional image can be generated by image processing. Complexity and difficulty are increased during the regional image processing due to some interference factors of aircraft in flight. The overlap of the acquired regional image is constantly variable. Depending on the analysis of the imaging geometric principle of a wide field-of-view scanning camera, this paper proposes the rigorous geometric model of geoposition. The infrared image mosaic technology is proposed according to the features of regional images through the SIFT (Scale Invariant Feature Transform) operator to extract the two best-matching point pairs in the adjacent overlap region. We realize the coarse registration of adjacent images according to image translation, rotation, and a scale model of image geometric transformation, and then the local fine stitching is realized using the normalized cross-correlation matching strategy. The regional mosaic experiment of aerial multi-detector parallel scanning infrared image is processed to verify the feasibility and efficiency of the proposed algorithm.

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Hideux, Michel, i Michel Abadie. "Cytologie ultrastructurale de l'anthère de Saxifraga. I. Période d'initiation des précurseurs des sporopollénines au niveau des principaux types exiniques". Canadian Journal of Botany 63, nr 1 (1.01.1985): 97–112. http://dx.doi.org/10.1139/b85-013.

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The period of initiation of sporopollenin precursors studied by transmission electron microscopy in the anthers of three species of the genus Saxifraga (S. cymbalaria ssp. huetiana, sempervivum and clusii) reveals two main phases. They are characterized successively by the elaboration of the ectexine (outer layer of the exine composed of sporopollenin) and endexine (inner layer of the same wall). This phenomenon has been observed in the tapetal periplasm and the sporal periplasm; the latter has been chosen as the reference point in establishing the chronology of the ontogenetic stages as well as the terminology of the sporopollenin structures. Proectexine and proendexine are distinctly stratified in the microspore while they become intermingled in the proorbicules. Proendexine could be elaborated according to a fluid mosaic model in relation to the plasmalemma. During this period, the relationships revealed between the plasmalemma–glycocalyx system (glycolemma) and the cytoskeleton (microtubules, microfilaments, and microfibrils) are emphasized. Thus, their functional role in the setting up of sporopollenin precursors is suggested.

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Gao, Rui, Changyun Miao i Xianguo Li. "Adaptive Multi-View Image Mosaic Method for Conveyor Belt Surface Fault Online Detection". Applied Sciences 11, nr 6 (12.03.2021): 2564. http://dx.doi.org/10.3390/app11062564.

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In order to improve the accuracy and real-time of image mosaic, realize the multi-view conveyor belt surface fault online detection, and solve the problem of longitudinal tear of conveyor belt, we in this paper propose an adaptive multi-view image mosaic (AMIM) method based on the combination of grayscale and feature. Firstly, the overlapping region of two adjacent images is preliminarily estimated by establishing the overlapping region estimation model, and then the grayscale-based method is used to register the overlapping region. Secondly, the image of interest (IOI) detection algorithm is used to divide the IOI and the non-IOI. Thirdly, only for the IOI, the feature-based partition and block registration method is used to register the images more accurately, the overlapping region is adaptively segmented, the speeded up robust features (SURF) algorithm is used to extract the feature points, and the random sample consensus (RANSAC) algorithm is used to achieve accurate registration. Finally, the improved weighted smoothing algorithm is used to fuse the two adjacent images. The experimental results showed that the registration rate reached 97.67%, and the average time of stitching was less than 500 ms. This method is accurate and fast, and is suitable for conveyor belt surface fault online detection.

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Fantini, Jacques, Nicolas Garmy, Radhia Mahfoud i Nouara Yahi. "Lipid rafts: structure, function and role in HIV, Alzheimer's and prion diseases". Expert Reviews in Molecular Medicine 4, nr 27 (20.12.2002): 1–22. http://dx.doi.org/10.1017/s1462399402005392.

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The fluid mosaic model of the plasma membrane has evolved considerably since its original formulation 30 years ago. Membrane lipids do not form a homogeneous phase consisting of glycerophospholipids (GPLs) and cholesterol, but a mosaic of domains with unique biochemical compositions. Among these domains, those containing sphingolipids and cholesterol, referred to as membrane or lipid rafts, have received much attention in the past few years. Lipid rafts have unique physicochemical properties that direct their organisation into liquid-ordered phases floating in a liquid-crystalline ocean of GPLs. These domains are resistant to detergent solubilisation at 4°C and are destabilised by cholesterol- and sphingolipid-depleting agents. Lipid rafts have been morphologically characterised as small membrane patches that are tens of nanometres in diameter. Cellular and/or exogenous proteins that interact with lipid rafts can use them as transport shuttles on the cell surface. Thus, rafts act as molecular sorting machines capable of co-ordinating the spatiotemporal organisation of signal transduction pathways within selected areas (‘signalosomes’) of the plasma membrane. In addition, rafts serve as a portal of entry for various pathogens and toxins, such as human immunodeficiency virus 1 (HIV-1). In the case of HIV-1, raft microdomains mediate the lateral assemblies and the conformational changes required for fusion of HIV-1 with the host cell. Lipid rafts are also preferential sites of formation for pathological forms of the prion protein (PrPSc) and of the β-amyloid peptide associated with Alzheimer's disease. The possibility of modulating raft homeostasis, using statins and synthetic sphingolipid analogues, offers new approaches for therapeutic interventions in raft-associated diseases.

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Tschirhart, Victoria, Sally Pehrsson, Colin Card, Eric G. Potter, Jeremy Powell i Dinu Pană. "Interpretation of buried basement in the southwestern Athabasca Basin, Canada, from integrated geophysical and geological datasets". Geochemistry: Exploration, Environment, Analysis 21, nr 1 (24.02.2020): geochem2019–061. http://dx.doi.org/10.1144/geochem2019-061.

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Recent discoveries of basement-hosted uranium deposits in the Patterson Lake corridor in the southwestern Athabasca Basin of Canada have brought vigorous exploration interest to the region. New lithostratigraphic constraints, geochronology and airborne geophysical surveys have dramatically improved the understanding of the host basement geology, warranting a re-examination of the remote predictive mapping and geophysical responses of the buried basement rocks. This study took a two-step approach to examine the regional basement geology and architecture. First, a mosaic of the long-wavelength response of potential field (gravity and magnetic) datasets was examined to divide the basement into regional domains based on bulk physical property variations. The interpretive geological model was then refined using textural and lineament analysis of new airborne gravity and magnetic datasets, geological drill hole logs and magnetic susceptibility measurements. The new basement map identifies and updates major features including a crustal-scale structure that separates the southern Tantato Domain from the newly defined eastern Taltson Domain. This structure may have played a role in localizing fluid flow in the Patterson Lake corridor, defining the spatial extents of structurally controlled buried felsic intrusions, and redefines the boundaries of the Taltson, Clearwater and Tantato Domains. In addition, the potential field enhancements delineated significant regional faults that controlled the geometry of Paleoproterozoic cover sequences and have implications for understanding the crustal architecture of the southern Rae Province. These new interpretations shed light on the tectonic history of the region to support on-going exploration activities and delineate regionally prospective areas in this understudied area of the Canadian Shield.Thematic collection: This article is part of the Uranium Fluid Pathways collection available at: https://www.lyellcollection.org/cc/uranium-fluid-pathways

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Harding, S. E., i P. Johnson. "Physicochemical studies on turnip-yellow-mosaic virus. Homogeneity, relative molecular masses, hydrodynamic radii and concentration-dependence of parameters in non-dissociating solvents". Biochemical Journal 231, nr 3 (1.11.1985): 549–55. http://dx.doi.org/10.1042/bj2310549.

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Turnip-yellow-mosaic virus, with its stable, highly spherical and monodisperse character, was chosen as a suitable model substance with which to test hydrodynamic theories of transport. Sedimentation coefficients, diffusion coefficients (obtained through photon correlation spectroscopy) and viscosities were measured accurately as a function of concentration in well-defined and nearly neutral buffer systems. Ancillary information was also obtained from very-low-speed sedimentation-equilibrium experiments. The coefficients expressing the variation in sedimentation and diffusion coefficients with weight concentration were obtained, and by combination with other data it was possible to avoid assumptions concerning solvation and transform such regression coefficients into the form appropriate to volume fractions. Some measure of support for Batchelor's [(1972) J. Fluid Mech. 52, 245-268] calculations was thus obtained, but over most of the pH range the coefficients were significantly smaller than those calculated from his theory. It seems likely that electrostatic interactions are responsible for the discrepancies. Hydrodynamic radii (from diffusion coefficients) were in very fair agreement with those calculated from the thermodynamic excluded-volume term, but were higher than indicated by electron microscopy and X-ray diffraction, a discrepancy ascribable to solvation.

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35

Hames, Océane, Mahdi Jafari, David Nicholas Wagner, Ian Raphael, David Clemens-Sewall, Chris Polashenski, Matthew D. Shupe, Martin Schneebeli i Michael Lehning. "Modeling the small-scale deposition of snow onto structured Arctic sea ice during a MOSAiC storm using snowBedFoam 1.0." Geoscientific Model Development 15, nr 16 (29.08.2022): 6429–49. http://dx.doi.org/10.5194/gmd-15-6429-2022.

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Abstract. The remoteness and extreme conditions of the Arctic make it a very difficult environment to investigate. In these polar regions covered by sea ice, the wind is relatively strong due to the absence of obstructions and redistributes a large part of the deposited snow mass, which complicates estimates for precipitation hardly distinguishable from blowing or drifting snow. Moreover, the snow mass balance in the sea ice system is still poorly understood, notably due to the complex structure of its surface. Quantitatively assessing the snow distribution on sea ice and its connection to the sea ice surface features is an important step to remove the snow mass balance uncertainties (i.e., snow transport contribution) in the Arctic environment. In this work we introduce snowBedFoam 1.0., a physics-based snow transport model implemented in the open-source fluid dynamics software OpenFOAM. We combine the numerical simulations with terrestrial laser scan observations of surface dynamics to simulate snow deposition in a MOSAiC (Multidisciplinary Drifting Observatory for the Study of Arctic Climate) sea ice domain with a complicated structure typical for pressure ridges. The results demonstrate that a large fraction of snow accumulates in their vicinity, which compares favorably against scanner measurements. However, the approximations imposed by the numerical framework, together with potential measurement errors (precipitation), give rise to quantitative inaccuracies, which should be addressed in future work. The modeling of snow distribution on sea ice should help to better constrain precipitation estimates and more generally assess and predict snow and ice dynamics in the Arctic.

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Alves, Anna Carolina Schneider, Reinaldo Antonio Dias, Luciano Porto Kagami, Gustavo Machado das Neves, Fernando Cidade Torres, Vera Lucia Eifler-Lima, Ivone Carvalho, Carolina de Miranda Silva i Daniel Fabio Kawano. "Beyond the "Lock and Key" Paradigm: Targeting Lipid Rafts to Induce the Selective Apoptosis of Cancer Cells". Current Medicinal Chemistry 25, nr 18 (22.05.2018): 2082–104. http://dx.doi.org/10.2174/0929867325666180111100601.

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For more than 40 years, the fluid mosaic model of cellular membranes has supported our vision of an inert lipid bilayer containing membrane protein receptors that are randomly hit by extracellular molecules to trigger intracellular signaling events. However, the notion that compartmentalized cholesterol- and sphingomyelin-rich membrane microdomains (known as lipid rafts) spatially arrange receptors and effectors to promote kinetically favorable interactions necessary for the signal transduction sounds much more realistic. Despite their assumed importance for the dynamics of ligand-receptor interactions, lipid rafts and biomembranes as a whole remain less explored than the other classes of biomolecules because of the higher variability and complexity of their membrane phases, which rarely provide the detailed atomic-level structural data in X-ray crystallography assays necessary for molecular modeling studies. The fact that some alkylphospholipids (e.g. edelfosine: 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine) selectively induce the apoptotic death of cancer cells by recruiting Fas death receptors and the downstream signaling molecules into clusters of lipid rafts suggests these potential drug targets deserve a more in-depth investigation. Herein, we review the structure of lipid rafts, their role in apoptotic signaling pathways and their potential role as drug targets for the treatment of cancer.

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Lhoest, Lancelot, Mimoun Lamrini, Jurgen Vandendriessche, Nick Wouters, Bruno da Silva, Mohamed Yassin Chkouri i Abdellah Touhafi. "MosAIc: A Classical Machine Learning Multi-Classifier Based Approach against Deep Learning Classifiers for Embedded Sound Classification". Applied Sciences 11, nr 18 (10.09.2021): 8394. http://dx.doi.org/10.3390/app11188394.

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Environmental Sound Recognition has become a relevant application for smart cities. Such an application, however, demands the use of trained machine learning classifiers in order to categorize a limited set of audio categories. Although classical machine learning solutions have been proposed in the past, most of the latest solutions that have been proposed toward automated and accurate sound classification are based on a deep learning approach. Deep learning models tend to be large, which can be problematic when considering that sound classifiers often have to be embedded in resource constrained devices. In this paper, a classical machine learning based classifier called MosAIc, and a lighter Convolutional Neural Network model for environmental sound recognition, are proposed to directly compete in terms of accuracy with the latest deep learning solutions. Both approaches are evaluated in an embedded system in order to identify the key parameters when placing such applications on constrained devices. The experimental results show that classical machine learning classifiers can be combined to achieve similar results to deep learning models, and even outperform them in accuracy. The cost, however, is a larger classification time.

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Weir, Tiffany L., Valerie J. Stull, Dayakar Badri, Lily A. Trunck, Herbert P. Schweizer i Jorge Vivanco. "Global Gene Expression Profiles Suggest an Important Role for Nutrient Acquisition in Early Pathogenesis in a Plant Model of Pseudomonas aeruginosa Infection". Applied and Environmental Microbiology 74, nr 18 (18.07.2008): 5784–91. http://dx.doi.org/10.1128/aem.00860-08.

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ABSTRACT Although Pseudomonas aeruginosa is an opportunistic pathogen that does not often naturally infect alternate hosts, such as plants, the plant-P. aeruginosa model has become a widely recognized system for identifying new virulence determinants and studying the pathogenesis of the organism. Here, we examine how both host factors and P. aeruginosa PAO1 gene expression are affected in planta after infiltration into incompatible and compatible cultivars of tobacco (Nicotiana tabacum L.). N. tabacum has a resistance gene (N) against tobacco mosaic virus, and although resistance to PAO1 infection is correlated with the presence of a dominant N gene, our data suggest that it is not a factor in resistance against PAO1. We did observe that the resistant tobacco cultivar had higher basal levels of salicylic acid and a stronger salicylic acid response upon infiltration of PAO1. Salicylic acid acts as a signal to activate defense responses in plants, limiting the spread of the pathogen and preventing access to nutrients. It has also been shown to have direct virulence-modulating effects on P. aeruginosa. We also examined host effects on the pathogen by analyzing global gene expression profiles of bacteria removed from the intracellular fluid of the two plant hosts. We discovered that the availability of micronutrients, particularly sulfate and phosphates, is important for in planta pathogenesis and that the amounts of these nutrients made available to the bacteria may in turn have an effect on virulence gene expression. Indeed, there are several reports suggesting that P. aeruginosa virulence is influenced in mammalian hosts by the availability of micronutrients, such as iron and nitrogen, and by levels of O2.

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Fang, Jingxin, i Xuwei Li. "Object Detection Related to Irregular Behaviors of Substation Personnel Based on Improved YOLOv4". Applied Sciences 12, nr 9 (24.04.2022): 4301. http://dx.doi.org/10.3390/app12094301.

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The accurate and timely detection of irregular behavior of substation personnel plays an important role in maintaining personal safety and preventing power outage accidents. This paper proposes a method for irregular behaviors detection (IBD) of substation personnel based on an improved YOLOv4 which uses MobileNetV3 to replace the CSPDarkNet53 feature extraction network, depthwise separable convolution and efficient channel attention (ECA) to optimize the SPP and PANet networks, and four scales of feature maps to fuse to improve the detection accuracy. First, an image dataset was constructed using video data and still photographs preprocessed by the gamma correction method. Then, the improved YOLOv4 model was trained by combining Mosaic data enhancement, cosine annealing, and label smoothing skills. Several detection cases were carried out, and the experimental results showed that the proposed improved YOLOv4 model has high accuracy, with a mean average precision (mAP) of 83.51%, as well as a fast detection speed, with a frames per second (FPS) of 38.06 pictures/s. This represents better performance than other object detection methods, including Faster RCNN, SSD, YOLOv3, and YOLOv4. This study offers a reference for the IBD of substation personnel and provides an automated intelligent monitoring method.

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Barera, Simone, Cristina Pagliano, Tillmann Pape, Guido Saracco i James Barber. "Characterization of PSII–LHCII supercomplexes isolated from pea thylakoid membrane by one-step treatment with α- and β-dodecyl- d -maltoside". Philosophical Transactions of the Royal Society B: Biological Sciences 367, nr 1608 (19.12.2012): 3389–99. http://dx.doi.org/10.1098/rstb.2012.0056.

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It was the work of Jan Anderson, together with Keith Boardman, that showed it was possible to physically separate photosystem I (PSI) from photosystem II (PSII), and it was Jan Anderson who realized the importance of this work in terms of the fluid-mosaic model as applied to the thylakoid membrane. Since then, there has been a steady progress in the development of biochemical procedures to isolate PSII and PSI both for physical and structural studies. Dodecylmaltoside (DM) has emerged as an effective mild detergent for this purpose. DM is a glucoside-based surfactant with a bulky hydrophilic head group composed of two sugar rings and a non-charged alkyl glycoside chain. Two isomers of this molecule exist, differing only in the configuration of the alkyl chain around the anomeric centre of the carbohydrate head group, axial in α-DM and equatorial in β-DM. We have compared the use of α-DM and β-DM for the isolation of supramolecular complexes of PSII by a single-step solubilization of stacked thylakoid membranes isolated from peas. As a result, we have optimized conditions to obtain homogeneous preparations of the C 2 S 2 M 2 and C 2 S 2 supercomplexes following the nomenclature of Dekker & Boekema (2005 Biochim. Biophys. Acta 1706 , 12–39). These PSII–LHCII supercomplexes were subjected to biochemical and structural analyses.

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Hu, Wenyi, Jinling Zou, Yuan Huang, Hongkun Wang, Kun Zhao, Mingzhe Liu i Shan Liu. "ECGYOLO: Mask Detection Algorithm". Applied Sciences 13, nr 13 (25.06.2023): 7501. http://dx.doi.org/10.3390/app13137501.

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Of past years, wearing masks has turned into a necessity in daily life due to the rampant new coronavirus and the increasing importance people place on health and life safety. However, current mask detection algorithms are difficult to run on low-computing-power hardware platforms and have low accuracy. To resolve this discrepancy, a lightweight mask inspection algorithm ECGYOLO based on improved YOLOv7tiny is proposed. This algorithm uses GhostNet to replace the original convolutional layer with ECG module instead of ELAN module, which greatly improves the inspection efficiency and decreases the parameters of the model. In the meantime, the ECA (efficient channel attention) mechanism is led into the neck section to boost the feature fetch capability of the channel, and Mosaic and Mixup data enhancement techniques are adopted in training to obtain mask images under different viewpoints to improve the comprehensiveness and effectiveness of the model. Experiments show that the mAP (mean average precision) of the algorithm is raised by 4.4% to 92.75%, and the number of arguments is decreased by 1.14 M to 5.06M compared with the original YOLOv7tiny. ECGYOLO is more efficient than other algorithms at present and can meet the real-time and lightweight needs of mask detection.

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Ye, Zhenchao, Jingwen Mao, Cai Yang, Juan Usca i Xinhao Li. "Trace Elements in Magnetite and Origin of the Mariela Iron Oxide-Apatite Deposit, Southern Peru". Minerals 13, nr 7 (13.07.2023): 934. http://dx.doi.org/10.3390/min13070934.

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To better understand the origin of the Andean iron oxide-apatite (IOA) deposits, we conducted a study on the geology and magnetite geochemistry of the Mariela IOA deposit in the Peruvian Iron Belt, central Andes. The Mariela deposit is hosted by gabbroic and dioritic intrusions. The major high-grade massive ores are primarily composed of magnetite and contain variable amounts of apatite and actinolite. Based on textural and geochemical characteristics, three different types of magnetite are recognized: Type I magnetite occurs in the massive magnetite ore, subclassified as inclusion-rich (I-a), inclusion-free (I-b), and mosaic (I-c); Type II magnetite is associated with abundant actinolite and titanite; and Type III magnetite is disseminated in altered host rocks. However, the magnetite geochemistry data for the Mariela deposit plot shows different genetic areas in [Ti + V] vs. [Al + Mn], Ti vs. V, and Fe vs. V/Ti discrimination diagrams, indicating a paradox of magmatic and hydrothermal origins. Our interpretation is as follows: Type I-a magnetite had an initial magmatic or high-temperature magmatic-hydrothermal origin, with slight modifications during transportation and subsequent hydrothermal precipitation (Types I-b and I-c). Type II magnetite is formed from hydrothermal fluid due to the presence of abundant actinolite. Disseminated magnetite (Type III) and veinlet-type magnetite formed after fluid replacement of the host rock. We stress that elemental discrimination diagrams should be combined with field studies and textural observations to provide a reasonable geological interpretation. A clear cooling trend is evident among the three subtypes of Type I magnetite (I-a, I-b, and I-c), as well as Type II and Type III magnetite, with average formative temperatures of 737 °C, 707 °C, 666 °C, 566 °C, and 493 °C, respectively. The microanalytical data on magnetite presented here support the magmatic-hydrothermal flotation model to explain the origin of IOA deposits in the Coastal Cordillera of Southern Peru.

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Arman, Ala, Claudio Badii, Pierfrancesco Bellini, Stefano Bilotta, Paolo Nesi i Michela Paolucci. "Analyzing Demand with Respect to Offer of Mobility". Applied Sciences 12, nr 18 (7.09.2022): 8982. http://dx.doi.org/10.3390/app12188982.

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A main key success for public transportation networks is their tuning by the analysis of mobility demand with respect to the offer in terms of public transportation means. Most of the solutions at the state of the art have strong limitations in taking into account: multiple contextual information as attractors/motivations for people movements, modalities of travel means, multiple operators, and a range of key performance indicators. For these reasons, a model for analyzing the demand with respect to the offer of mobility has been studied, and the corresponding tool DORAM developed. DORAM allows to perform the analysis of alternative scenarios, as what-if analyses, when the transport service offer and the mobility demand changed in the scenario, adopting a fast-computation strategy to compare scenarios with the aim of detecting/identifying motivations of crowded conditions on stops and on the vehicles. The analysis can exploit a wide range of data sources when computing a set of key performance indicators. The DORAM solution has been defined and developed in the MOSAIC research and development project with ALSTOM and other companies. The DORAM solution is validated by using real data and conditions in the Tuscany region.

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Zarranz, Juan J. "Clinical and molecular aspects of progressive degenerative aphasias". ANALES RANM 135, nr 135(02) (30.12.2018): 52–58. http://dx.doi.org/10.32440/ar.2018.135.02.supl01.art06.

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The debate between equipotentiality or specialization of the cerebral cortex as a substrate for higher neurological functions lasted until the second half of the 19th century. The classic observations of Broca, Wernicke and other authors demonstrating the language alterations due to cortical focal lesions were decisive in solving the problem and gave rise to a localization current, similar to that of the phrenologists, but not speculative but neuropathologically based. This vision of the cerebral cortex as a mosaic of autonomous specialized areas has been superseded and complemented by modern neuroscience that supports brain functions in a networked anatomical-functional model, with more or less specific areas or nodes, cortical and subcortical. Other classic authors such as Pick have already pointed out that aphasia could be, in addition to a consequence of focal vascular lesions, an early symptom of degenerative diseases. Mesulam more modernly, retrieved that idea and coined the concept of primary progressive aphasia. Later, it has been shown that primary or degenerative progressive aphasia is a heterogeneous process both clinically with at least three varieties, non-fluid, semantic and logopenic, and pathologically and in its molecular substrate, which currently includes tau pathology, TDP43. and Alzheimer. There is an imperfect correlation between the clinical variety of aphasia, the preferred location of neurodegeneration, histology, and molecular pathology. The new molecular neuroimaging techniques (amyloid-PET, PET-tau) and other markers can help to refine the clinical-pathological correlation and help to better understand the reasons for this selective vulnerability of one or other brain areas involved in the anatomy.physiology of language.

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Brown, Dennis, Richard Bouley, Teodor G. Pǎunescu, Sylvie Breton i Hua A. J. Lu. "New insights into the dynamic regulation of water and acid-base balance by renal epithelial cells". American Journal of Physiology-Cell Physiology 302, nr 10 (15.05.2012): C1421—C1433. http://dx.doi.org/10.1152/ajpcell.00085.2012.

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Maintaining tight control over body fluid and acid-base homeostasis is essential for human health and is a major function of the kidney. The collecting duct is a mosaic of two cell populations that are highly specialized to perform these two distinct processes. The antidiuretic hormone vasopressin (VP) and its receptor, the V2R, play a central role in regulating the urinary concentrating mechanism by stimulating accumulation of the aquaporin 2 (AQP2) water channel in the apical membrane of collecting duct principal cells. This increases epithelial water permeability and allows osmotic water reabsorption to occur. An understanding of the basic cell biology/physiology of AQP2 regulation and trafficking has informed the development of new potential treatments for diseases such as nephrogenic diabetes insipidus, in which the VP/V2R/AQP2 signaling axis is defective. Tubule acidification due to the activation of intercalated cells is also critical to organ function, and defects lead to several pathological conditions in humans. Therefore, it is important to understand how these “professional” proton-secreting cells respond to environmental and cellular cues. Using epididymal proton-secreting cells as a model system, we identified the soluble adenylate cyclase (sAC) as a sensor that detects luminal bicarbonate and activates the vacuolar proton-pumping ATPase (V-ATPase) via cAMP to regulate tubular pH. Renal intercalated cells also express sAC and respond to cAMP by increasing proton secretion, supporting the hypothesis that sAC could function as a luminal sensor in renal tubules to regulate acid-base balance. This review summarizes recent advances in our understanding of these fundamental processes.

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Xiao, Z., i P. N. Devreotes. "Identification of detergent-resistant plasma membrane microdomains in dictyostelium: enrichment of signal transduction proteins." Molecular Biology of the Cell 8, nr 5 (maj 1997): 855–69. http://dx.doi.org/10.1091/mbc.8.5.855.

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Unlike most other cellular proteins, the chemoattractant receptor, cAR1, of Dictyostelium is resistant to extraction by the zwitterionic detergent, CHAPS. We exploited this property to isolate a subcellular fraction highly enriched in cAR1 by flotation of CHAPS lysates of cells in sucrose density gradients. Immunogold electron microscopy studies revealed a homogeneous preparation of membrane bilayer sheets. This preparation, designated CHAPS-insoluble floating fraction (CHIEF), also contained a defined set of 20 other proteins and a single uncharged lipid. Cell surface biotinylation and preembedding immunoelectron microscopy both confirmed the plasma membrane origin of this preparation. The cell surface phosphodiesterase (PDE) and a downstream effector of cAR1, adenylate cyclase (ACA), were specifically localized in these structures, whereas the cell adhesion molecule gp80, most of the major cell surface membrane proteins, cytoskeletal components, the actin-binding integral membrane protein ponticulin, and G-protein alpha- and beta-subunits were absent. Overall, CHIFF represents about 3-5% of cell externally exposed membrane proteins. All of these results indicate that CHIFF is derived from specialized microdomains of the plasma membrane. The method of isolation is analogous to that of caveolae. However, we were unable to detect distinct caveolae-like structures on the cell surface associated with cAR1, which showed a diffuse staining profile. The discovery of CHIFF facilitates the purification of cAR1 and related signaling proteins and the biochemical characterization of receptor-mediated processes such as G-protein activation and desensitization. It also has important implications for the "fluid mosaic" model of the plasma membrane structures.

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Fragata, Ana, Jorge Ribeiro, Carla Candeias, Ana Velosa i Fernando Rocha. "Archaeological and Chemical Investigation on the High Imperial Mosaic Floor Mortars of the Domus Integrated in the Museum of Archaeology D. Diogo de Sousa, Braga, Portugal". Applied Sciences 11, nr 17 (6.09.2021): 8267. http://dx.doi.org/10.3390/app11178267.

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This paper intends to characterize the floor mortar layers (nucleus, rudus and statumen) of the high imperial mosaics of the domus integrated in the Museum of Archeology D. Diogo de Sousa, the oldest roman housing testimonies known in Braga, Portugal. It offers an important archaeological and historical contextualization and first chemical characterization attempt on the mortars. The study of 13 mortar samples was carried out at a chemical level through X-ray fluorescence spectroscopy (XRF). All samples presented low lime content when compared to similar studies. A high chemical similarity between nucleus mortars (opus signinum) and chemical composition differences between rudus and statumen mortars was determined, confirmed by statistical analyses. Their composition was distinctly related to the stratigraphic position of each floor mortar layer, following Vitruvius’ model, and to the external conditions and treatments (e.g., capillary rise with soluble salts and application of chemical treatments), to which they were submitted.

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Papadopoulou, Ermioni-Eirini, Apostolos Papakonstantinou, Nikolaos Zouros i Nikolaos Soulakellis. "Scale-Variant Flight Planning for the Creation of 3D Geovisualization and Augmented Reality Maps of Geosites: The Case of Voulgaris Gorge, Lesvos, Greece". Applied Sciences 11, nr 22 (13.11.2021): 10733. http://dx.doi.org/10.3390/app112210733.

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The purpose of this paper was to study the influence of cartographic scale and flight design on data acquisition using unmanned aerial systems (UASs) to create augmented reality 3D geovisualization of geosites. The relationship between geographical and cartographic scales, the spatial resolution of UAS-acquired images, along with their relationship with the produced 3D models of geosites, were investigated. Additionally, the lighting of the produced 3D models was examined as a key visual variable in the 3D space. Furthermore, the adaptation of the 360° panoramas as environmental lighting parameters was considered. The geosite selected as a case study was the gorge of the river Voulgaris in the western part of the island of Lesvos, which is located in the northeastern part of the Aegean Sea in Greece. The methodology applied consisted of four pillars: (i) scale-variant flight planning, (ii) data acquisition, (iii) data processing, (iv) AR, 3D geovisualization. Based on the geographic and cartographic scales, the flight design calculates the most appropriate flight parameters (height, speed, and image overlaps) to achieve the desired spatial resolution (3 cm) capable of illustrating all the scale-variant details of the geosite when mapped in 3D. High-resolution oblique aerial images and 360° panoramic aerial images were acquired using scale-variant flight plans. The data were processed using image processing algorithms to produce 3D models and create mosaic panoramas. The 3D geovisualization of the geosite selected was created using the textured 3D model produced from the aerial images. The panoramic images were converted to high-dynamic-range image (HDRI) panoramas and used as a background to the 3D model. The geovisualization was transferred and displayed in the virtual space where the panoramas were used as a light source, thus enlightening the model. Data acquisition and flight planning were crucial scale-variant steps in the 3D geovisualization. These two processes comprised the most important factors in 3D geovisualization creation embedded in the virtual space as they designated the geometry of the 3D model. The use of panoramas as the illumination parameter of an outdoor 3D scene of a geosite contributed significantly to its photorealistic performance into the 3D augmented reality and virtual space.

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Folega, Fousseni, Wouyo Atakpama, Hodabalo Pereki, Badabaté Diwediga, Ivan Pontin Novotny, Anne Dray, Claude Garcia, Kperkouma Wala, Komlan Batawila i Kofi Akpagana. "Geo-Based Assessment of Vegetation Health Related to Agroecological Practices in the Southeast of Togo". Applied Sciences 13, nr 16 (10.08.2023): 9106. http://dx.doi.org/10.3390/app13169106.

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In the context of climate change, the need to contribute to achieving Sustainable Development Goal (SDG) 2 is no longer in doubt, especially in sub-Saharan Africa. In this study of the landscape within 10 km of the Donomadé model farm, southeastern Togo, researchers sought to assess vegetation health in ecosystems and agrosystems, including their capacity to produce biomass for agroecological practices. Sentinel-2 sensor data from 2015, 2017, 2020, and 2022 were preprocessed and used to calculate the normalized vegetation fire ratio index (NBR), the vegetation fire severity index (dNBR), and CASA-SEBAL models. From these different analyses, it was found that vegetation stress increased across the landscape depending on the year of the time series. The research estimated that 9952.215 ha, 10,397.43 ha, and 9854.90 ha were highly stressed in 2015, 2017, and 2020, respectively. Analysis of the level of interannual severity revealed the existence of highly photosynthetic areas that had experienced stress. These areas, which were likely to have been subjected to agricultural practices, were estimated to be 8704.871 ha (dNBR2017–2015), 8253.17 ha (dNBR2020–2017), and 7513.93 ha (dNBR2022–2020). In 2022, the total available biomass estimated by remote sensing was 3,741,715 ± 119.26 kgC/ha/y. The annual average was 3401.55 ± 119.26 kgC/ha/y. In contrast, the total area of healthy vegetation was estimated to be 4594.43 ha, 4301.30 ha, and 4320.85 ha, in 2015, 2017, and 2022, respectively. The acceptance threshold of the net primary productivity (NPP) of the study area was 96%. The coefficient of skewness (0.81 ± 0.073) indicated a mosaic landscape. Productive and functional ecosystem components were present, but these were highly dispersed. These findings suggest a great opportunity to promote agroecological practices. Mulching may be an excellent technique for enhancing overall ecosystem services as targeted by the SDGs, by means of reconversion of plant biomass consumed by vegetation fires or slash-and-burn agricultural practices.

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Pantaleo, M., i T. R. Walter. "The ring-shaped thermal field of Stefanos crater, Nisyros Island: a conceptual model". Solid Earth 5, nr 1 (1.04.2014): 183–98. http://dx.doi.org/10.5194/se-5-183-2014.

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Abstract. Fumarole fields related to hydrothermal processes release the heat of the underground through permeable pathways. Thermal changes, therefore, are likely to depend also on the size and permeability variation of these pathways. There may be different explanations for the observed permeability changes, such as fault control, lithology, weathering/alteration, heterogeneous sediment accumulation/erosion and physical changes of the fluids (e.g., temperature and viscosity). A common difficulty, however, in surface temperature field studies at active volcanoes is that the parameters controlling the ascending routes of fluids are poorly constrained in general. Here we analyze the crater of Stefanos, Nisyros (Greece), and highlight complexities in the spatial pattern of the fumarole field related to permeability conditions. We combine high-resolution infrared mosaics and grain-size analysis of soils, aiming to elaborate parameters controlling the appearance of the fumarole field. We find a ring-shaped thermal field located within the explosion crater, which we interpret to reflect near-surface contrasts of the soil granulometry and volcanotectonic history at depth. We develop a conceptual model of how the ring-shaped thermal field formed at the Stefanos crater and similarly at other volcanic edifices, highlighting the importance of local permeability contrast that may increase or decrease the thermal fluid flux.

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