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Bourden, S., R. Ben Aim e M. Mietton-Peuchot. "Etude par capteur optique du dépôt formé lors de la filtration d'une suspension de bentonite sur fibre creuse". Revue des sciences de l'eau 6, n.º 2 (12 de abril de 2005): 115–29. http://dx.doi.org/10.7202/705169ar.
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Lors de la filtration sur fibres creuses de suspensions de bentonite, il a été mis en évidence que le facteur limitant est la formation d'un dépôt à la surface de la fibre. Parlant de ces considérations, un dispositif optique a été mis au point pour suivre l'évolution spatio-temporelle du dépôt en cours de filtration sur fibre creuse à peau externe. Ainsi, il a pu être mis en évidence que l'influence de la vitesse d'écoulement n'est sensible qu'après un certain temps de filtration ou un certain volume filtré. Dans le domaine testé des faibles vitesses d'écoulement, il existe une période initiale où la loi de filtration sur gâteau est applicable.Dans le cas de fibres creuses à peau externe, l'optimum technique (productivité maximale) ou économique (coût minimal du m3 traité) serait donc plus à rechercher dans une optimisation de la séquence filtration-lavage que dans une augmentation de la vitesse d'écoulement. L'efficacité du réentraînement du dépôt lors du lavage peut être suivie grâce à l'équipement et au capteur développés.
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BLIN, Capucine, Marcos OLIVEIRA, Christel CAUSSERAND, Yannick FAYOLLE e Vincent ROCHER. "Validation d’un protocole de vieillissement accéléré de membranes fibres creuses à l’échelle semi-industrielle". TSM 12 2023, TSM 12 2023 (20 de dezembro de 2023): 179–98. http://dx.doi.org/10.36904/tsm/202312179.
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Les membranes d’ultrafiltration se dégradent au cours de leurs années de fonctionnement, notamment à cause du colmatage et des nettoyages qu’elles subissent. Ce vieillissement provoque sur le long terme des problèmes d’exploitation sur les sites de traitement des eaux usées utilisant des bioréacteurs à membranes qui peuvent se traduire par des arrêts fréquents pour nettoyage et une diminution de la capacité filtrante pouvant aboutir à un remplacement des membranes. À ce jour, les mécanismes de vieillissement en bioréacteurs à membranes et leurs impacts sur les propriétés des membranes sont partiellement identifiés. L’objectif de ce travail est de proposer et valider une méthode de vieillissement accéléré de membranes fibres creuses à l’échelle d’un pilote semi-industriel (volume utile de 2 m³) dans des conditions représentatives de celles mises en œuvre sur les sites industriels (longueur des fibres, contraintes hydrodynamiques, séquençage de l’aération). Pour cela, un pilote de filtration membranaire a été exploité pendant deux ans dans des conditions similaires des cuves membranaires de la station de traitement des eaux de Seine Aval (Siaap, Yvelines, 6,5 millions d’eq-habitant). Afin d’accélérer le vieillissement, les membranes sont soumises à de plus fortes doses d’exposition au chlore : des nettoyages par trempage dans une solution de Javel à 1 000 ppm puis d’acide citrique à 2 000 ppm ont été réalisés tous les deux mois (vs un tous les six mois sur site). Afin de valider cette méthode de vieillissement, les résultats des caractérisations des fibres prélevées sur le pilote sont comparés à ceux retrouvés pour les fibres prélevées des bioréacteurs à membranes du Siaap. Les analyses des mesures de physico-chimie de surface, de perméabilité, de propriétés mécaniques et morphologiques ont permis de conclure à la pertinence de l’approche développée pour le suivi du vieillissement accéléré en conditions d’usage à l’échelle pilote, au regard des évolutions observées à l’échelle industrielle.
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Furferi, Rocco, e Monica Carfagni. "Colour Mixing Modelling and Simulation: Optimization of Colour Recipe for Carded Fibres". Modelling and Simulation in Engineering 2010 (2010): 1–9. http://dx.doi.org/10.1155/2010/487678.
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Colour matching between carded and finished fibres is an important challenge for textile industry. The straightforward approach for mixing together some differently coloured fibres in order to obtain a blend of a desired colour is to perform a trial and error approach starting from a given colour recipe and optimizing it with several attempts. Unfortunately, dyeing process so as the carding procedure may result in a carded fibre whose colour is different from the desired one. As a consequence textile companies have to modify the original recipe in order to reduce the gap between the colour of the final product and the desired one. The present work describes a model able to simulate the colour mixing of fibres in order to assess the best recipe. The model consists in two modules: a “prediction module” predicts the colour of a blend obtained by mixing together several fibres; an “optimization module” is used to optimize the final recipe. The devised system has been tested for optimizing the recipe of a set of 200 blends. The mean error in predicting the blend colour is about 15% with a variance of 0.165. The time for optimizing the recipe is reduced by 92%.
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Núñez, R., I. Antón e G. Sala. "Proof-of-concept of a building-integrated hybrid concentrator photovoltaics-lighting system". Lighting Research & Technology 50, n.º 7 (11 de julho de 2017): 1082–90. http://dx.doi.org/10.1177/1477153517719119.
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A hybrid concentrator photovoltaics (CPV) module that combines the production of electricity and transports sunlight is proposed as a means to reduce the energy needs of buildings by two complementary solar energy approaches. Both concepts share the need for a solar tracker and an infrastructure to concentrate the sunlight which allows a reduction in costs of the proposed system. The CPV part is a well-known technology to produce electricity that serves as a host for the light subpart that transports sunlight through optical fibres. Measurements of a proof-of-concept show that in nominal conditions the lighting subpart is more efficient in the task of transporting sunlight than converting sunlight to electricity and then to light again. The efficiency threshold is a direct function of the fibre material and distance transported and the generated light is very similar to the solar light in terms of spectral content. Based on PMMA optical fibres and conventional CPV technology, the hybrid module converts 28.7% of the sunlight into electricity. Regarding the light transported by the optical fibres they slightly shift sunlight to bluish white but the quality of light is still comparable to a typical fluorescent lamp used in offices.
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Logoń, Dominik, Krzysztof Schabowicz, Maciej Roskosz e Krzysztof Fryczowski. "The Increase in the Elastic Range and Strengthening Control of Quasi Brittle Cement Composites by Low-Module Dispersed Reinforcement: An Assessment of Reinforcement Effects". Materials 14, n.º 2 (12 de janeiro de 2021): 341. http://dx.doi.org/10.3390/ma14020341.
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This paper presents the possibility of using low-module polypropylene dispersed reinforcement (E = 4.9 GPa) to influence the load-deflection correlation of cement composites. Problems have been indicated regarding the improvement of elastic range by using that type of fibre as compared with a composite without reinforcement. It was demonstrated that it was possible to increase the ability to carry stress in the Hooke’s law proportionality range in mortar and paste types of composites reinforced with low-module fibres, i.e., Vf = 3% (in contrast to concrete composites). The possibility of having good strengthening and deflection control in order to limit the catastrophic destruction process was confirmed. In this paper, we identify the problem of deformation assessment in composites with significant deformation capacity. Determining the effects of reinforcement based on a comparison with a composite without fibres is suggested as a reasonable approach as it enables the comparison of results obtained by various universities with different research conditions.
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Soussan, L., M. Alquier, C. Guigui, S. Alfenore, S. Mathe e C. Cabassud. "Characterization of the inline virus removal performances in hollow fibre modules by a new tracer electrochemically detected". Water Supply 13, n.º 2 (1 de março de 2013): 507–14. http://dx.doi.org/10.2166/ws.2013.054.
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In a previous work, an innovative and patented method was presented, that is based on a new virus surrogate. This surrogate is an enzyme-labelled MS2 phage that is directly detectable and quantifiable by amperometry thanks to its induced enzymatic activity. In this work, this method was used to characterize the dynamics of virus removal in micromodules as a function of the membrane defect size and the transmembrane pressure (TMP). Experiments were performed at lab scale with an integer module and with modules made with the same fibres with calibrated holes (50, 100, 150 μm) made in one of the module fibres with the laser method. Results showed first that the new method allowed diagnosing a 50 μm hole on the fibre of a micromodule. It was also demonstrated that, whatever the applied TMP, removal performances are all the more better that the defect size is smaller. Moreover, whatever the hole size, a TMP step rise from 1 to 1.5 bar during tracer filtration led to no significant change in the observed removal but improved the intrinsic removal performances.
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Sridang, P. Choksuchart, M. Heran e A. Grasmick. "Influence of module configuration and hydrodynamics in water clarification by immersed membrane systems". Water Science and Technology 51, n.º 6-7 (1 de março de 2005): 135–42. http://dx.doi.org/10.2166/wst.2005.0631.
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Different immersed membrane systems were compared according to the module configuration. Filtering concentrated aqueous suspensions under constant permeate flux, the hydraulic performances of the systems were evaluated and compared through parameters such as critical permeate flux notion and trans-membrane pressure variation rates. Operational variables were membrane size and module fibre density, aeration inside or outside the fibre network, suspension concentration and physico-chemical conditioning. When using hollow fibres including a possible air injection inside the fibre network, results pointed out the positive role of the aeration on the fouling control. But too high a fibre density did not allow an optimal control when the aqueous suspension was very concentrated. On the other hand, when working with capillary membranes showing sufficient space between fibres, the major parameters were the transversal suspension flow circulation through the fibre network and the FeCl3 conditioning of the suspension. Experimental results show a possible working at a 0.07 m3.m2.h1 permeate flow rate under low TMP evolutions, 0.02 Pa/s, even if the filtration was operated under high concentrated suspension, 5 kgSS/m3.
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Hermansen, Tyge Dahl, Søren Ventegodt e Isack Kandel. "Human Development XI: The Structure of the Cerebral Cortex. Are There Really Modules in the Brain?" Scientific World JOURNAL 7 (2007): 1922–29. http://dx.doi.org/10.1100/tsw.2007.256.
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The structure of human consciousness is thought to be closely connected to the structure of cerebral cortex. One of the most appreciated concepts in this regard is the Szanthagothei model of a modular building of neo-cortex. The modules are believed to organize brain activity pretty much like a computer. We looked at examples in the literature and argue that there is no significant evidence that supports Szanthagothei's model. We discuss the use of the limited genetic information, the corticocortical afferents termination and the columns in primary sensory cortex as arguments for the existence of the cortex-module. Further, we discuss the results of experiments with Luminization Microscopy (LM) colouration of myalinized fibres, in which vertical bundles of afferent/efferent fibres that could support the cortex module are identified. We conclude that sensory maps seem not to be an expression for simple specific connectivity, but rather to be functional defined. We also conclude that evidence for the existence of the postulated module or column does not exist in the discussed material. This opens up for an important discussion of the brain as functionally directed by biological information (information-directed self-organisation), and for consciousness being closely linked to the structure of the universe at large. Consciousness is thus not a local phenomena limited to the brain, but a much more global phenomena connected to the wholeness of the world.
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Guigui, C., M. Mougenot e C. Cabassud. "Air sparging backwash in ultrafiltration hollow fibres for drinking water production". Water Supply 3, n.º 5-6 (1 de dezembro de 2003): 415–22. http://dx.doi.org/10.2166/ws.2003.0197.
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Air sparging was applied to improve backwash efficiency for an ultrafiltration inside/out hollow-fibre module operating in dead-end mode. Air was injected into the retentate side only during the backwash period. The filtration experiments were performed on a semi-industrial scale pilot using a clay suspension as a model of surface waters. The backwash procedure consisted of two steps: in a first step (phase A), air was added to the feed water inside the fibre lumen at the bottom of the module. In a second step (phase B), cleaned water backwash was performed. Different air velocities were used and the kinetics of particle removal were studied with turbidity measurements of backwash waters. The experimental results showed that using an air–fluid mixing allows one to increase the quantity of particles removed from the hollow fibres. For the phase A, the removed mass is higher when the air velocity and duration of air injection increased. But, even at very low air velocity (0.08 m/s), a high backwash efficiency was observed. Experiments with filtration/air-sparging backwash cycles concluded that using air–fluid mixing in the backwash sequence allowed prevention of long-term fouling and reduced the rate of fouling during the filtration period.
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Gogić, Ilja. "On derivations and elementary operators on C*-algebras". Proceedings of the Edinburgh Mathematical Society 56, n.º 2 (21 de março de 2013): 515–34. http://dx.doi.org/10.1017/s0013091512000302.
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AbstractLet A be a unital C*-algebra with the canonical (H) C*-bundle $\mathfrak{A}$ over the maximal ideal space of the centre of A, and let E(A) be the set of all elementary operators on A. We consider derivations on A which lie in the completely bounded norm closure of E(A), and show that such derivations are necessarily inner in the case when each fibre of $\mathfrak{A}$ is a prime C*-algebra. We also consider separable C*-algebras A for which $\mathfrak{A}$ is an (F) bundle. For these C*-algebras we show that the following conditions are equivalent: E(A) is closed in the operator norm; A as a Banach module over its centre is topologically finitely generated; fibres of $\mathfrak{A}$ have uniformly finite dimensions, and each restriction bundle of $\mathfrak{A}$ over a set where its fibres are of constant dimension is of finite type as a vector bundle.
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HRIVNIAK, LUKAS, JOZEF SVETLIK, MICHAL SASALA e STEFAN ONDOCKO. "OPTIMIZATION OF THE UNIVERSAL ROTARY MODULE URM THROUGH ADDITIVE MANUFACTURING OF COMPOSITE MATERIALS". MM Science Journal 2021, n.º 4 (13 de outubro de 2021): 4901–5. http://dx.doi.org/10.17973/mmsj.2021_10_2021046.
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The article deals with the ongoing development of the universal rotary module URM 02. The high weight of the components from which the modules are assembled proved to be a significant problem. As well as the weight of the connecting parts that are needed to assemble the manipulator or robotic arm. Design changes have resulted in a reduction in weight compared to older generations of modules, but in order for the manipulator to function properly, further weight reduction is required. The article describes the procedure for lightening components by changing the material and the design changes that result from it. The original aluminium alloy was replaced by a continuous carbon fibres composite produced using CFR (Continuous Fiber Reinforcement) additive technology. Here you should describe the paper idea in short.
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HRIVNIAK, LUKAS, JOZEF SVETLIK, MICHAL SASALA e STEFAN ONDOCKO. "OPTIMIZATION OF THE UNIVERSAL ROTARY MODULE URM THROUGH ADDITIVE MANUFACTURING OF COMPOSITE MATERIALS". MM Science Journal 2021, n.º 4 (13 de outubro de 2021): 4901–5. http://dx.doi.org/10.17973/mmsj.2021_10_2021046.
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The article deals with the ongoing development of the universal rotary module URM 02. The high weight of the components from which the modules are assembled proved to be a significant problem. As well as the weight of the connecting parts that are needed to assemble the manipulator or robotic arm. Design changes have resulted in a reduction in weight compared to older generations of modules, but in order for the manipulator to function properly, further weight reduction is required. The article describes the procedure for lightening components by changing the material and the design changes that result from it. The original aluminium alloy was replaced by a continuous carbon fibres composite produced using CFR (Continuous Fiber Reinforcement) additive technology. Here you should describe the paper idea in short.
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Stroppel, Catharina. "Parabolic category O, perverse sheaves on Grassmannians, Springer fibres and Khovanov homology". Compositio Mathematica 145, n.º 4 (julho de 2009): 954–92. http://dx.doi.org/10.1112/s0010437x09004035.
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AbstractFor a fixed parabolic subalgebra 𝔭 of $\mathfrak {gl}(n,\mathbb {C})$ we prove that the centre of the principal block 𝒪0𝔭 of the parabolic category 𝒪 is naturally isomorphic to the cohomology ring H*(ℬ𝔭) of the corresponding Springer fibre. We give a diagrammatic description of 𝒪0𝔭 for maximal parabolic 𝔭 and give an explicit isomorphism to Braden’s description of the category PervB(G(k,n)) of Schubert-constructible perverse sheaves on Grassmannians. As a consequence Khovanov’s algebra ℋn is realised as the endomorphism ring of some object from PervB(G(n,n)) which corresponds under localisation and the Riemann–Hilbert correspondence to a full projective–injective module in the corresponding category 𝒪0𝔭. From there one can deduce that Khovanov’s tangle invariants are obtained from the more general functorial invariants in [C. Stroppel, Categorification of the Temperley Lieb category, tangles, and cobordisms via projective functors, Duke Math. J. 126(3) (2005), 547–596] by restriction.
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Woillez, J., J. A. Abad, R. Abuter, E. Aller Carpentier, J. Alonso, L. Andolfato, P. Barriga et al. "NAOMI: the adaptive optics system of the Auxiliary Telescopes of the VLTI". Astronomy & Astrophysics 629 (setembro de 2019): A41. http://dx.doi.org/10.1051/0004-6361/201935890.
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Context. The tip-tilt stabilisation system of the 1.8 m Auxiliary Telescopes of the Very Large Telescope Interferometer was never dimensioned for robust fringe tracking, except when atmospheric seeing conditions are excellent. Aims. Increasing the level of wavefront correction at the telescopes is expected to improve the coupling into the single-mode fibres of the instruments, and enable robust fringe tracking even in degraded conditions. Methods. We deployed a new adaptive optics module for interferometry (NAOMI) on the Auxiliary Telescopes. Results. We present its design, performance, and effect on the observations that are carried out with the interferometric instruments.
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Osong, Sinke H., Sven Norgren, Per Engstrand, Mathias Lundberg e Peter Hansen. "Crill: A novel technique to characterize nano-ligno-cellulose". Nordic Pulp & Paper Research Journal 29, n.º 2 (1 de maio de 2014): 190–94. http://dx.doi.org/10.3183/npprj-2014-29-02-p190-194.
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Abstract The CrillEye is a technique for qualitatively assessing loose slender and fibrillar particles created during pulping. It has also been demonstrated that the crill measurement technique can easily be used to measure the degree of fibrillation of mechanical pulp based nano-ligno-cellulose (NLC). The measurement technique is based on an optical response of a suspension at two wavelengths of light; UV and IR. The UV light contains information on both fibres and crill, while IR only contains information on fibres. The resolution on the CrillEye module is based on optical response of the pulp and on an analogue signal analysis making it concentration independent. Characterization of particlesize distribution of nano-ligno-cellulose is both important and challenging. The objective of the work presented in this paper was to study the crill values of TMP and CTMP based nano-ligno-celluloses as a function of homogenization time. Results showed that the crill value of both TMP-NLC and CTMP-NLC correlated fairly well with the homogenization time.
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Brodmann, Markus P., e Rodney Y. Sharp. "On the dimension and multiplicity of local cohomology modules". Nagoya Mathematical Journal 167 (2002): 217–33. http://dx.doi.org/10.1017/s0027763000025484.
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AbstractThis paper is concerned with a finitely generated module M over a (commutative Noetherian) local ring R. In the case when R is a homomorphic image of a Gorenstein local ring, one can use the well-known associativity formula for multiplicities, together with local duality and Matlis duality, to produce analogous associativity formulae for the local cohomology modules of M with respect to the maximal ideal. The main purpose of this paper is to show that these formulae also hold in the case when R is universally catenary and such that all its formal fibres are Cohen–Macaulay.These formulae involve certain subsets of the spectrum of R called the pseudosupports of M; these pseudo-supports are closed in the Zariski topology when R is universally catenary and has the property that all its formal fibres are Cohen–Macaulay. However, examples are provided to show that, in general, these pseudo-supports need not be closed. We are able to conclude that the above-mentioned associativity formulae for local cohomology modules do not hold over all local rings.
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Atlaskin, A. A., S. S. Kryuchkov, A. N. Stepakova, I. S. Moiseenko, N. S. Tsivkovsky, K. A. Smorodin, A. N. Petukhov, M. E. Atlaskina e I. V. Vorotyntsev. "Influence of the Approach to Membrane Mass Transfer Characteristics Determination on the Process Simulation Results". Мембраны и мембранные технологии 13, n.º 6 (1 de novembro de 2023): 464–74. http://dx.doi.org/10.31857/s2218117223060032.
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In this work, the dependence of the output characteristics determined in the simulation of the gas separation membrane process on the gas transport characteristics of the membrane specified as parameters of the membrane module model has been investigated. The study was carried out on a laboratory setup containing polyphenylene oxide hollow fibres. As a result of this integrated study, including theoretical and experimental approaches, it has been determined that when using the ideal gas transport characteristics obtained for pure gases to simulate the process, the error expressed in achievable concentration of the target component in the product stream ranges from 1.5 to 8.8% compared to the experimentally obtained values for the same module geometry and the same membrane area. This discrepancy can lead both to unattainable targets for the technological line and to an incorrect technical and economic evaluation of the process. Thus, the design of technological lines using mathematical modelling tools should be based on the “effective” gas transport characteristics of the material and/or product obtained for the components of real gas mixtures or simulating real gas mixtures.
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Pollet, S., C. Guigui e C. Cabassud. "Fouling and its reversibility in relation to flow properties and module design in aerated hollow fibre modules for membrane bioreactors". Water Science and Technology 57, n.º 4 (1 de março de 2008): 629–36. http://dx.doi.org/10.2166/wst.2008.113.
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Nowadays, most membrane bioreactors are using membranes submerged in the biomass and aeration in the concentrate compartment to limit or to control fouling. An important issue for the design of modules or membrane bundles in MBRs is to understand how the air/liquid flow is behaving and influencing fouling and its reversibility in relationship to the module properties. This paper focuses on an innovative and very specific process, in which HF membranes are put in a cartridge outside the activated sludge tank and a recycling loop is associated to the cartridge in order to decrease concentration of foulant species at the membrane surface and mass transfer resistance. Recycling operates with a very low liquid velocity in the module (a few cm·s−1) which constitutes a specificity of this process in terms of filtration operation. The aim of this study is to characterise two-phase flow and its effects on fouling and fouling reversibility at the scale of a semi-industrial bundle of outside/in hollow fibres, and as a function of bundle properties (packing density, fibre diameter), using specific methods to characterise the flow and fouling effects. Two modules were used showing a different packing density. Filtration was operated at constant permeate flux with clay suspension at 0.65 g·l−1 in the same hydrodynamic conditions. Fouling kinetics and irreversibility were characterised by an adapted step method, and gas and liquid flows were characterised at global scale by residence time distribution analyses and gas hold-up. Fouling velocities are clearly influenced by gas velocity. The proportion of dead to total volume in the module is mainly affected by the liquid flow velocity and module design. The module with the higher fibre diameter and the lower packing density showed better performances in terms of fouling which was correlated with better flow properties.
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Knöll, B., e H. Beck. "The cytoskeleton and nucleus: the role of actin as a modulator of neuronal gene expression". e-Neuroforum 17, n.º 1 (1 de janeiro de 2011): 1–5. http://dx.doi.org/10.1007/s13295-010-0013-y.
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AbstractActin, arranged for example in stress fibres, provides a fundamental cytoskeletal framework function to all cell types. Notably, there is now mounting evidence that, in addition to cytoplasmic cytoskeletal regulation, actin treadmilling provides a signal modulating nuclear gene expression. In altering gene regulation, cytoplasmic and most likely also a nucleus-resident actin provides an additional (gene) regulatory twist to cell motility. So far, the transcription factor serum response factor (SRF) alongside its myocardin-related transcription factor (MRTF) cofactors has emerged as the main target of actin dynamics. In this review, we discuss the impact of actin signalling on nuclear gene expression in the nervous system, where the actin-MRTF-SRF module contributes to various processes including neuronal motility.
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Lim, Keng, Hui An, Peng Wang, Guiqin Liu e Simon Yu. "Theoretical and Computational Analysis on Double-End Submerged Hollow Fibre Membrane Modules". Energies 11, n.º 5 (24 de abril de 2018): 1042. http://dx.doi.org/10.3390/en11051042.
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This paper studies the potential increase in permeate output flow rate that submerged hollow fibres can achieve when operating in double-end suction. The flow dynamics of submerged hollow fibre membranes with different combinations of fibre inner diameter, membrane thickness, and membrane permeability were numerically simulated. Fibre features (fibre inner diameter, membrane thickness, and membrane permeability) are then characterised for their effects on the increment in permeate flow rate due to change in configuration. Concurrently, an analytical model of a fibre in double-end suction is modelled. Analysis on the double-end fibre model has indicated that the fibre characteristic ratio, λ, has a direct influence on the relative increase in output flow rate when both ends are open. Parametric investigations on the three fibre features have shown that their effects on relative output increase agree with the co-relations indicated by λ. For fibres with λ less than 4, a proportional relationship between a fibre’s λ value and the percentage increment in permeate flow rate is observed when adopting double-end suction. The fibre characteristic ratio, λ, in addition to characterising flux uniformity, can further be used to consider the effectiveness of applying double-end suction in Submerged Hollow Fibre Membrane Module (SHFMM) systems at the design stage.
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Daniel, Geoffrey, Lada Filonova, Åsa M. Kallas e Tuula T. Teeri. "Morphological and chemical characterisation of the G-layer in tension wood fibres of Populus tremula and Betula verrucosa: Labelling with cellulose-binding module CBM1 Hj Cel7A and fluorescence and FE-SEM microscopy". Holzforschung 60, n.º 6 (1 de novembro de 2006): 618–24. http://dx.doi.org/10.1515/hf.2006.104.
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Abstract The gelatinous layer (G-layer) formed on the lumen wall in early- and latewood fibres of poplar and birch tension wood was characterised using a novel molecular marker specific for crystalline cellulose in conjunction with fluorescence and FE-SEM microscopy. Crystalline cellulose was localised using a cloned Cel7A cellulose-binding module (CBM1 Hj Cel7A) from the fungus Hypocrea jecorina conjugated directly to FITC/TRITC or indirectly via a secondary antibody conjugated to FITC for fluorescence microscopy or to gold/silver for FE-SEM. With the CBM1 Hj Cel7A conjugate, the G-layer was clearly distinguished from other secondary cell-wall layers as a bright green layer visible in fibres of tension wood in fluorescence microscopy. FEM-SEM images revealed the supramolecular architecture of the G-layer of poplar wood, which consists of well-defined, often concentrically orientated, cellulose aggregates of the order of 30–40 nm. The cellulose aggregates typically have a microfibril angle of almost 0°. Studies on cellulose marked with CBM1 Hj Cel7A followed by Au labelling and Ag enhancement complemented the fluorescence observations. The studies demonstrate the usefulness of this novel molecular marker for crystalline cellulose in situ, which was previously difficult to localise. Further proof of distinct cellulose aggregates was observed.
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Ihamouchen, Chadia, Hocine Djidjelli, Amar Boukerrou, Françoise Fenouillot e Clair Barres. "Comportement mécanique et propriétés thermique des composites polyéthyènes renforcés par des fibres lignocellolusiques". Matériaux & Techniques 106, n.º 6 (2018): 601. http://dx.doi.org/10.1051/mattech/2018064.
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Un intéret particulier a été porté au grignons dʼolive, qui est un sous produit des rejets des différentes huileries. Chaque année, des milliers de tonnes de ce produit sont incinérés ou carrément rejetés dans la nature. Ce dernier, dont les caractéristiques restent à valoriser, est mis à profit par son incorporation comme charge dans lʼélaboration des matériaux composites à matrice polyéthylène haute densité (PEHD). Pour réduire le caractère hydrophile de la farine, un agent compatibilisant (polyéthylène greffé anhydride maléique) commercialisé sous le nom XA255 a été utilisé. Les échantillons obtenus par extrusion et injection seront ensuite caractérisés par différentes techniques dʼanalyse à savoir, le test de traction, lʼanalyse thermogravimétrique (ATG/DTG), lʼanalyse enthalpique différentielle (DSC) et lʼanalyse microscopique électronique à balayage (MEB). Avec lʼincorporation de la farine de grignon dʼolive (FGO) dans la matrice PEHD, la contrainte à la rupture diminue, tandis que la rigidité du matériau et le taux de cristallinité augmentent. Après traitement, on enregistre une amélioration, à la fois de la contrainte à la rupture et du module de Young, due principalement à une meilleure adhésion fibre/matrice, confirmée par lʼanalyse MEB. Lʼanalyse thermogravimétrique a montré une meilleure stabilité thermique des formulations F30 traitée, qui se manifeste par la diminution de la vitesse maximale de décomposition.
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Rossignol, J. M., R. Séguéla e F. Rietsch. "Models mecanique pour les fibres de polyethylene lineaire basse densite d'apres la variation du module d'elasticite avec l'etirage". Makromolekulare Chemie. Macromolecular Symposia 9, n.º 1 (julho de 1987): 27–38. http://dx.doi.org/10.1002/masy.19870090106.
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Alguacil, Francisco Jose, e Jose Ignacio Robla. "Treatment of Stainless Steel Rinse Waters Using Non-Dispersive Extraction and Strip Dispersion Membrane Technology". Membranes 13, n.º 12 (6 de dezembro de 2023): 902. http://dx.doi.org/10.3390/membranes13120902.
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The extraction of Fe(III), Cr(III), and Ni(II) from stainless steel rinse water using non-dispersive extraction and strip dispersion membrane technology was carried out in a microporous hydrophobic hollow-fibre module contactor. The fibres were of polypropylene, whereas the organic extractant DP8R (bis(2-ethylhexyl) phosphoric acid) diluted in ExxsolD100 was used as the carrier phase. The rinse water containing the three elements was passed through the tube side, and the pseudo-emulsion formed by the organic phase of DP8R in Exxol D100 and an acidic strip solution were passed through the shell side in a counter-current operation; thus, a unique hollow fibre module was used for extraction and stripping. In non-dispersive extraction and strip dispersion technology, the stripping solution was dispersed into the organic membrane solution in a vessel with an adequate mixing device (impeller) designed to form strip dispersion. This pseudo-emulsion was circulated from the vessel to the membrane module to provide a constant supply of the organic phase to the membrane pores. Different hydrodynamic and chemical variables, such as variation in feed and pseudo-emulsion flow rates, strip phase composition, feed phase pH, and extractant concentration in the organic phase, were investigated. Mass transfer coefficients were estimated from the experimental data. It was possible to separate and concentrate the metals present in the rinse water using the non-dispersive extraction and strip dispersion technique.
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Lekha, Prabashni, Tamara Bush, Norman Pammenter, Bruce Sitholè e Patricia Berjak. "Quantitative assessment of xylan distribution across the secondary cell wall layers of Eucalyptus dissolving pulp fibres". Holzforschung 72, n.º 1 (20 de dezembro de 2017): 1–8. http://dx.doi.org/10.1515/hf-2017-0070.
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AbstractA quantitative method has been developed for assessment of the distribution of xylan across the secondary cell wall layers ofEucalyptusdissolving pulp fibres by means of a carbohydrate binding module (CBM),CtCBM6, in combination with transmission electron microscopy (TEM). To ensure reproducibility and to minimise non-specific labelling, various parameters were optimised, namely the size of the gold colloid marker,CtCBM6 concentration, and the selection of buffer solutions. The method was replicated on processedEucalyptusfibres containing different xylan contents. Reproducible xylan counts and distributions across the secondary cell wall layers were obtained for unbleached and bleachedEucalyptusfibres. The xylan distribution pattern across the cell wall layers S1, S2 and S3 was similar, but the S1 and S3 layers contained after bleaching more xylan than the S2 layer. The technique has a wide range of applications in basic wood research as well as in the analysis of technological processes.
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Abdelmalik, Abdelghaffar Amoka, e Knut Brede Liland. "Electric field enhancement control in active junction of IGBT power module". Journal of Physical Science 31, n.º 3 (25 de novembro de 2020): 1–15. http://dx.doi.org/10.21315/jps2020.31.3.1.
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Dielectric liquids are incompressible, able to fill voids and have selfhealing effect and hence are being considered as alternative encapsulation materials to establish power electronics at ambient high pressure at subsea conditions. In a long-term endurance test, insulated-gate bipolar transistor (IGBT) chips subjected to 6.5 kV DC stress in dielectric oil environment was reported to have failed after less than one week in operation. A critical look at the failed objects revealed contamination fibres at the surface and around the high field regions. This paper presents the numerical simulation of field distribution around a conducting fibre at the surface of the IGBT chip. It also evaluates the influence of the nature of the encapsulation material on the integrity of power electronic modules using a long-term experiment at a medium elevated temperature for high and low relative humidity operated close to service load using IGBT relevant chips. Finite element method (FEM) calculations show how the high field region can be shielded from impurities that can easily trigger partial discharge (PD) and breakdown. The simulation suggests that coating the surface of the module with a thin polymer layer with a thickness of 20 μm or more could be sufficient to improve the reliability of the encapsulation system. Additional polymer coat with thickness 27 μm on the chip made the system survive without failure for 67 weeks under test and dry operating condition. Meanwhile, thick coating such as silicone gel protected the object longer under higher relative humidity.
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Brehant, Anne, Karl Glucina, Isabelle Lemoigne e Jean-Michel Laine. "Risk management approach for monitoring UF membrane integrity and experimental validation using MS2-phages". Water Supply 8, n.º 2 (1 de julho de 2008): 239–44. http://dx.doi.org/10.2166/ws.2008.051.
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Low-pressure membrane filtration systems, such as microfiltration (MF) and ultrafiltration (UF), have received a great deal of attention in the past 15 years due to their ability to remove microbial pathogens, especially Cryptosporidium and Giardia. The major concern for the application of membrane technology is, however, how to ensure integrity of these barriers, since small defects in membranes could result in a significant reduction in pathogen removal efficiency. In order to ensure safe drinking water treatment, a number of environmental agencies request the membrane operators to conduct regular direct integrity tests to control the microbial log removal values (LRV) of the plants. Typically, test conditions must be selected to provide information on defects larger than 3 μm to ensure Cryptosporidium removal. In that context, the objective of this project was to develop and validate, both at bench-scale and full-scale, a model based on the equations proposed by USEPA and ASTM that uses the air flow rate throughout a defect during the air pressure test for predicting the microbial LRV. The project was conducted on a pressurised low-pressure membrane module. MS2-phages were used at bench-scale to validate the model and the selected assumptions with various calibrated defects carried out on the membrane fibres. The validity of the model was then evaluated at full-scale. A user-friendly tool using the Hagen Poiseuille Model proposed by the ASTM was developed to assist membrane operators in the integrity monitoring. The calibration of the model with full-scale tests resulted in adjusting some key-parameters representing air diffusion, flow regime and particles deposition. The numerical applications provide a very reliable result in predicting the pathogen removal efficiency and the equivalent number of broken fibres. This model could detect one complete broken fibre out of more than 700,000 fibres, which guaranteed more than 4 log of microorganism removal efficiency.
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Lecerf, J. M., A. Cayzeele, F. Depeint, E. Clerc, Y. Dugenet, H. Jacobs e P. Pouillart. "O29 Une nouvelle combinaison de fibres à effet prébiotique module les cytokines de l’inflammation et diminue le lipopolysaccharide circulant". Diabetes & Metabolism 36 (março de 2010): A8. http://dx.doi.org/10.1016/s1262-3636(10)70033-1.
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Wang, Y., K. W. Ong, M. W. D. Brannock e G. L. Leslie. "Evaluation of membrane bioreactor performance via residence time distribution: effects of membrane configuration and mixing". Water Science and Technology 57, n.º 3 (1 de fevereiro de 2008): 353–59. http://dx.doi.org/10.2166/wst.2008.114.
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Unlike conventional wastewater treatment systems that have a single effluent discharge point, membrane bioreactors (MBR) may have multiple extraction points resulting from the location of the membrane element in the reactor. This leads to multiple residence time distributions for an MBR system. One method to characterise the mixing is based on the concept of residence time distribution (RTD). A set of RTDs were generated using the conservative tracer, lithium chloride, for pilot plant MBRs with capacity up to 300 m3/day. Flat sheet and hollow fibre pilot plant MBR systems were operated in parallel on primary effluent collected at the Bedok Water Reclamation Plant in the republic of Singapore. Analysis of the RTD profiles indicated that membrane geometry did not impact on the kinetic conversion associated with nitrification because both MBRs were in well mixed conditions. However, the energy required to achieve perfect mixing with a hollow fibre module MBR, as defined by the velocity gradient, was lower than that with a flat sheet module MBR. The implication is that energy input associated with reactor mixing will depend on the configuration of the membrane. The difference in energy requirements between flat sheets and hollow fibres is such that careful consideration should be given to membrane selection in larger municipal installations.
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Kroulíková, Tereza, Ilya Astrouski e Miroslav Raudenský. "CHAOTISED POLYMERIC HOLLOW FIBRE BUNDLE AS A CROSSFLOW HEAT EXCHANGER IN AIR-WATER APPLICATION". Acta Polytechnica 60, n.º 4 (1 de setembro de 2020): 318–23. http://dx.doi.org/10.14311/ap.2020.60.0318.
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Fifteen years ago, polymeric hollow fibre heat exchangers were presented for the first time. Nowadays there are not only the shell-and-tube types as there were at the beginning. In this paper, six chaotised polymeric hollow fibre bundles with a different number of fibres were studied. The bundles presented varied in their fibre diameter, number and shape. These bundles were fixed into the module in such a way that the middle part serves as a cross-flow heat exchanger in an air tunnel. They were tested for air-water application with three different airflow rates. The overall heat transfer coefficients were determined, and the inner and outer heat transfer coefficients were derived. The modules presented achieved a heat transfer rate of up to 1309 W. The overall heat transfer coefficient reached a maximum of 339 Wm−2 K−1.
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Kokutse, Adzo Dzifa, Afiwa Dzigbodi Akpenè, Olivier Monteuuis, Arcadius Akossou, Patrick Langbour, Daniel Guibal, Mario F. Tomazello, Edjidomélé Gbadoe, Gilles Chaix e Kouami Kokou. "SELECTION OF PLUS TREES FOR GENETICALLY IMPROVED TEAK VARIETIES PRODUCED IN BENIN AND TOGO". BOIS & FORETS DES TROPIQUES 328, n.º 328 (20 de julho de 2017): 55. http://dx.doi.org/10.19182/bft2016.328.a31302.
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Cette étude vise la sélection d’arbres« plus » sur la base des caractères den- drométriques et des propriétés du bois dans des plantations de teck au Bénin et au Togo. La croissance de 569 arbres dans 5 forêts au Togo et 90 arbres dans 3 forêts au Bénin a été évaluée en mesu- rant le diamètre à hauteur de poitrine, la hauteur totale et la hauteur du fût. Les propriétés suivantes du bois ont été éva- luées et prises en compte pour la sélec- tion finale d’arbres « plus » : densité, pourcentage de bois de cœur et couleur. La durabilité naturelle du bois de cœur, le point de saturation des fibres, le module d’élasticité et les retraits ont été évalués sur la base de modèles spectroscopiques dans le proche infrarouge, préalablement construits. Nos résultats montrent qu’au Togo la variabilité inter-arbres en forêt est assez forte pour l’accroissement annuel en hauteur (0,81 ± 0,27 m), en circonfé- rence (2,95 ± 1,02 cm) et en hauteur des fûts (10,64 ± 3,51m). Au Bénin, si les per- formances dendrométriques des arbres ne varient pas de façon significative entre les forêts, pour la hauteur des fûts (10,99 ± 3,80 m), les valeurs du coeffi- cient de variation sont plus élevées (40 %) pour la forêt de Koto. Prenant en compte les propriétés du bois, la sélection finale multicritères montre que les peuplements d’Avétonou et de Tchorogo au Togo consti- tuent un groupe homogène affichant les plus fortes valeurs pour la densité du bois et le pourcentage de bois de cœur. Les arbres des forêts de Haho-Baloe et Eto ont des valeurs plus faibles pour la dura- bilité naturelle, le module d’élasticité, le pourcentage de bois de cœur et la densité du bois. Au Bénin, les arbres de la forêt d’Agrimey ont une densité plus élevée mais les valeurs pour le point de satu- ration des fibres, la durabilité naturelle et le retrait du bois sont similaires pour les trois forêts. La variabilité des perfor- mances dendrométriques et de la qualité du bois des arbres-candidat nous ont per- mis de sélectionner 33 arbres « plus ».
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Gentile, Cosimo, Giacomo Lunghi, Luca Rosario Buonocore, Francesca Cordella, Mario Di Castro, Alessandro Masi e Loredana Zollo. "Manipulation Tasks in Hazardous Environments Using a Teleoperated Robot: A Case Study at CERN". Sensors 23, n.º 4 (10 de fevereiro de 2023): 1979. http://dx.doi.org/10.3390/s23041979.
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Remote robotic systems are employed in the CERN accelerator complex to perform different tasks, such as the safe handling of cables and their connectors. Without dedicated control, these kinds of actions are difficult and require the operators’ intervention, which is subjected to dangerous external agents. In this paper, two novel modules of the CERNTAURO framework are presented to provide a safe and usable solution for managing optical fibres and their connectors. The first module is used to detect touch and slippage, while the second one is used to regulate the grasping force and contrast slippage. The force reference was obtained with a combination of object recognition and a look-up table method. The proposed strategy was validated with tests in the CERN laboratory, and the preliminary experimental results demonstrated statistically significant increases in time-based efficiency and in the overall relative efficiency of the tasks.
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Blok, Lourens, Marco Longana e Benjamin Woods. "Fabrication and Characterisation of Aligned Discontinuous Carbon Fibre Reinforced Thermoplastics as Feedstock Material for Fused Filament Fabrication". Materials 13, n.º 20 (20 de outubro de 2020): 4671. http://dx.doi.org/10.3390/ma13204671.
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In this work, aligned discontinuous fibre composite (ADFRC) tapes were developed and investigated as precursors for a novel 3D printing filament. ADFRCs have the potential to achieve mechanical performance comparable to continuous fibre reinforced composites, given sufficient fibre length and high level of alignment, and avoid many of the manufacturing difficulties associated with continuous fibres, e.g., wrinkling, bridging and corner radii constraints. Their potential use for fused filament fabrication (FFF) techniques was investigated here. An extensive down-selection process of thermoplastic matrices was performed, as matrix properties significantly impact both the processing and performance of the filament. This resulted in four candidate polymers (ABS, PLA, Nylon, PETG) which were used to manufacture ADFRC tapes with a Vf of 12.5% using the high performance discontinuous fibre (HiPerDiF) technology and an in-house developed continuous consolidation module. Tensile stiffness and strength up to 30 GPa and 400 MPa respectively were recorded, showing that a discontinuous fibre filament has the potential to compete with continuous fibre filaments.
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Machado, João, Adriano Araújo, Ricardo Pinto e Francisco M. Gama. "Studies on the interaction of the carbohydrate binding module 3 from the Clostridium thermocellum CipA scaffolding protein with cellulose and paper fibres". Cellulose 16, n.º 5 (23 de abril de 2009): 817–24. http://dx.doi.org/10.1007/s10570-009-9294-0.
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McDonough, John E., Naftali Kaminski, Bernard Thienpont, James C. Hogg, Bart M. Vanaudenaerde e Wim A. Wuyts. "Gene correlation network analysis to identify regulatory factors in idiopathic pulmonary fibrosis". Thorax 74, n.º 2 (26 de outubro de 2018): 132–40. http://dx.doi.org/10.1136/thoraxjnl-2018-211929.
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BackgroundIdiopathic pulmonary fibrosis (IPF) is a severe lung disease characterised by extensive pathological changes. The objective for this study was to identify the gene network and regulators underlying disease pathology in IPF and its association with lung function.MethodsLung Tissue Research Consortium dataset with 262 IPF and control subjects (GSE47460) was randomly divided into two non-overlapping groups for cross-validated differential gene expression analysis. Consensus weighted gene coexpression network analysis identified overlapping coexpressed gene modules between both IPF groups. Modules were correlated with lung function (diffusion capacity, DLCO; forced expiratory volume in 1 s, FEV1; forced vital capacity, FVC) and enrichment analyses used to identify biological function and transcription factors. Module correlation with miRNA data (GSE72967) identified associated regulators. Clinical relevance in IPF was assessed in a peripheral blood gene expression dataset (GSE93606) to identify modules related to survival.ResultsCorrelation network analysis identified 16 modules in IPF. Upregulated modules were associated with cilia, DNA replication and repair, contractile fibres, B-cell and unfolded protein response, and extracellular matrix. Downregulated modules were associated with blood vessels, T-cell and interferon responses, leucocyte activation and degranulation, surfactant metabolism, and cellular metabolic and catabolic processes. Lung function correlated with nine modules (eight with DLCO, five with FVC). Intermodular network of transcription factors and miRNA showed clustering of fibrosis, immune response and contractile modules. The cilia-associated module was able to predict survival (p=0.0097) in an independent peripheral blood IPF cohort.ConclusionsWe identified a correlation gene expression network with associated regulators in IPF that provides novel insight into the pathological process of this disease.
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Labesse, Gilles, Thomas Alexandre, Laurène Vaupré, Isabelle Salard-Arnaud, Joséphine Lai Kee Him, Ahmed Haouz, Bertrand Raynal, Patrick Bron e Hélène Munier-Lehmann. "Functional CBS modules make IMPDHs octameric". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 de agosto de 2014): C1283. http://dx.doi.org/10.1107/s2053273314087166.
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Inosine-5'-monophosphate dehydrogenase (1, 2) (IMPDH) is a major target for antiviral, antiparasitic, antileukemic and immunosuppressive therapies. It is an ubiquitous and essential enzyme for the biosynthesis of guanosine nucleotides. Up to now, IMPDHs have been reported as tetrameric enzymes harbouring a catalytic domain and a tandem of cystathionine-ß-synthase (CBS) modules. The latter had no precise function assigned despite their nearly absolute conservation among IMPDHs and consistent indication of their importance in vivo. The aim of our study was to provide evidence for the role of the CBS modules on the quaternary structure and on the regulation of IMPDHs. A multidisciplinary approach involving enzymology, site-directed mutagenesis, analytical ultracentrifugation, X-ray crystallography, SAXS, cryo-electron microscopy and molecular modelling allowed us to demonstrate that the Pseudomonas aeruginosa IMPDH is functionally active as an octamer and allosterically regulated by MgATP via each CBS module. Revisiting deposited structural data, we found this newly discovered octameric organization conserved in other IMPDH structures. Meanwhile, we demonstrated that the human IMPDH1 formed two distinct octamers that can pile up into isolated fibres in the presence of MgATP while its pathogenic mutant D226N, localised into the CBS domains, appeared to form massively aggregating fibres. The dramatic impact of this mutation could explain the severe retinopathy adRP10. Our data (3) revealed for the first time that IMPDH has an octameric architecture modulated by MgATP binding to the CBS modules, inducing large structural rearrangements. Thus, the regulatory CBS modules in IMPDHs are functional and they can either modulate catalysis or/and macromolecular assembly. Targeting the conserved effector binding pockets identified within the CBS modules might be promising to develop antibacterial compounds or drugs to counter retinopathy onset.
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Walczak, Agata, Ireneusz Naworol, Daniel Pieniak, Kamil Pasierbiewicz e Grzegorz Dzień. "Experimental studies on changes in mechanical properties of polymer composites under impact of thermal load determined based on compression testing". MATEC Web of Conferences 247 (2018): 00027. http://dx.doi.org/10.1051/matecconf/201824700027.
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The objective of the study was to carry out an analysis of changes in mechanical properties of polymer composites in conditions of thermal load. Such an analysis may allow an initial verification of possibilities of deploying new composites in production of fire helmet shells. The reference material chosen for testing was the Ultramid composite, which is currently used for the production of fire helmet shells. In addition three different materials were selected that contained reinforcement by glass fibres bearing the trade name of Tarnamid, which are not used in manufacturing of shells. Testing was conducted in conditions of quasi-static load, during which compressive tests were performed. Mechanical loads were applied at different levels of thermal exposure, which was to simulate presence in fire conditions. Results of tests indicated that the Tarnamid composites are characterised by better compressive strength and rigidity determined on the basis of the Young module value than Ultramid PA66 GF25 used in the production of head protective shells. It has also been proven that thermal loads contribute to significant degradation in strength and rigidity of tested materials, which affects adversely protective properties of the helmet.
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Aiello, S., A. Albert, S. Alves Garre, Z. Aly, A. Ambrosone, F. Ameli, M. Andre et al. "KM3NeT broadcast optical data transport system". Journal of Instrumentation 18, n.º 02 (1 de fevereiro de 2023): T02001. http://dx.doi.org/10.1088/1748-0221/18/02/t02001.
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Abstract The optical data transport system of the KM3NeT neutrino telescope at the bottom of the Mediterranean Sea will provide more than 6000 optical modules in the detector arrays with a point-to-point optical connection to the control stations onshore. The ARCA and ORCA detectors of KM3NeT are being installed at a depth of about 3500 m and 2500 m, respectively and their distance to the control stations is about 100 kilometers and 40 kilometers. In particular, the two detectors are optimised for the detection of cosmic neutrinos with energies above about 1 TeV (ARCA) and for the detection of atmospheric neutrinos with energies in the range 1 GeV–1 TeV (ORCA). The expected maximum data rate is 200 Mbps per optical module. The implemented optical data transport system matches the layouts of the networks of electro-optical cables and junction boxes in the deep sea. For efficient use of the fibres in the system the technology of Dense Wavelength Division Multiplexing is applied. The performance of the optical system in terms of measured bit error rates, optical budget are presented. The next steps in the implementation of the system are also discussed.
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DOUGABKA, Dao, Jean GÉRARD, Tikri BIANZEUBE, Morgane DENDONCKER, Caroline VINCKE, Rémy MARCHAL, Daniel GUIBAL e Alban GUYOT. "Variations des caractéristiques physiques et mécaniques du bois de Balanites aegyptiaca en fonction de trois provenances". BOIS & FORETS DES TROPIQUES 349 (15 de setembro de 2021): 7–21. http://dx.doi.org/10.19182/bft2021.349.a36776.
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Balanites aegyptiaca est une espèce caractéristique et emblématique des zones sèches d’Afrique et d’Asie. Elle revêt une grande importance socio-économique dans toute sa zone naturelle de répartition du fait de ses multiples usages. Toutefois, les propriétés technologiques de son bois sont mal connues, d’où des utilisations parfois inappropriées mais qui pourraient être élargies. Afin de mieux adapter ses applications à ses caractéristiques, nous avons déterminé les indicateurs de stabilité physique (masse volumique, infradensité, retrait radial total, retrait tangentiel total, retrait volumique total et point de saturation des fibres) et les indicateurs de comportement mécanique (module d’élasticité longitudinal, contrainte de rupture en flexion et compression) de ce bois. Quatre-vingt-treize éprouvettes prélevées dans 13 arbres provenant des zones sahélienne et soudanienne tchadiennes, et de la zone sahélienne sénégalaise ont été testées. Les résultats obtenus montrent que, pour les trois provenances, le bois de B. aegyptiaca est mi-lourd (797 kg/m3) avec une stabilité dimensionnelle moyenne : l’anisotropie de retrait est supérieure à 2 (2,2), le retrait radial total et le retrait tangentiel total sont moyens, respectivement égaux à 4 % et 8,5 %. Ses caractéristiques mécaniques sont moyennes (contraintes de rupture en compression et flexion statique respectivement égales à 49,4 MPa et 104,5 MPa) à faible (module d’élasticité longitudinal de 10 473 MPa). Une comparaison des résultats obtenus en fonction des zones de prélèvement a mis en évidence des tendances variables selon les caractéristiques étudiées. Ces variations entre les trois provenances restent cependant limitées. Les résultats de l’étude montrent que le bois de B. aegyptiaca pourrait être utilisé de façon appropriée sous forme de matériau pour une plus large gamme d’emplois, sous réserve de la mise en place d’une gestion adaptée permettant sa restauration par plantation.
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Seghman, Petr, Lukáš Krátký e Tomáš Jirout. "Effect of membrane separation process conditions on the recovery of syngas components". Acta Polytechnica 62, n.º 3 (30 de junho de 2022): 394–99. http://dx.doi.org/10.14311/ap.2022.62.0394.
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The presented study focuses on inspecting the dependency between process conditions, especially permeate and retentate pressure and component recovery of H2, CO, and CO2 during a membrane separation of model syngas. Experiments with both pure components and a model mixture were performed using a laboratory membrane unit Ralex GSU-LAB-200 with a polyimide hollow fibre module with 3000 hollow fibres. Permeability values were established at 1380 Barrer for H2, 23 Barrer for CO, and 343 Barrer for CO2. The measured selectivities differ from the ideal ones: the ideal H2/CO2 selectivity is 3.21, while the experimental values range from over 4 to as low as 1.2 (this implies that an interaction between the components occurs). Then, the model syngas, comprised of 16% H2, 34% CO, and 50% CO2, was tested. The recovery of each component decreases with an increasing permeate pressure. At a pressure difference of 2 bar, the recovery rate for H2, for a permeate pressure of 1.2 bar, is around 68%, for 2.5 bar, the values drop to 51%, and for 4 bar, the values reach 40% only. A similar trend was observed for CO2, with recovery values of 59%, 47% and 37% for permeate pressures of 1.2 bar, 2.5 bar and 4 bar, respectively.
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Mikolajczak, Janine, Hanna Zimmermann, Ahmad Kheirkhah, Ella Maria Kadas, Timm Oberwahrenbrock, Rodrigo Muller, Aiai Ren et al. "Patients with multiple sclerosis demonstrate reduced subbasal corneal nerve fibre density". Multiple Sclerosis Journal 23, n.º 14 (3 de novembro de 2016): 1847–53. http://dx.doi.org/10.1177/1352458516677590.
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Background: Many studies in multiple sclerosis (MS) have investigated the retina. Little, however, is known about the effect of MS on the cornea, which is innervated by the trigeminal nerve. It is the site of neural-immune interaction with local dendritic cells reacting in response to environmental stimuli. Objective: This study aims to investigate the effect of MS on corneal nerve fibres and dendritic cells in the subbasal nerve plexus using in vivo confocal microscopy (IVCM). Methods: We measured the corneal nerve fibre and dendritic cell density in 26 MS patients and matched healthy controls using a Heidelberg Retina Tomograph with cornea module. Disease severity was assessed with the Multiple Sclerosis Functional Composite, Expanded Disability Status Scale, visual acuity and retinal optical coherence tomography. Results: We observed significant reduction in total corneal nerve fibre density in MS patients compared to controls. Dendritic cell density was similar in both groups. Reduced total nerve fibre density was associated with worse clinical severity but not with previous clinical trigeminal symptoms, retinal neuro-axonal damage, visual acuity or disease duration. Conclusion: Corneal nerve fibre density is a promising new imaging marker for the assessment of disease severity in MS and should be investigated further.
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Waite, J. H., E. Vaccaro, C. Sun e J. M. Lucas. "Elastomeric gradients: a hedge against stress concentration in marine holdfasts?" Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 357, n.º 1418 (28 de fevereiro de 2002): 143–53. http://dx.doi.org/10.1098/rstb.2001.1025.
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The byssal threads of marine mussels are elastomeric fibres with a great capacity for absorbing and dissipating energy. Up to 70% of the total absorbed energy can be dissipated in the byssus. Because byssal threads attach the mussel to hard inert surfaces in its habitat, they must combine the need to be good shock absorbers with appropriate matching of Young's modulus between living tissue and a hard sub–stratum such as stone—stiffnesses that can differ by five orders of magnitude. Recent data suggest that improved modulus matching and decreased stress concentration between different portions of the byssus is achieved by the use of protein gradients. Protein gradients in byssal threads are constructed using natural macromolecular chimeras having a central collagenous domain, variable flanking modules and histidine–rich amino and carboxy termini. Stiff silk–like flanking modules prevail distally, while at the animal end, rubbery modules resembling elastin predominate. In between the two thread ends there is a mix of both module types. The histidine–rich termini provide metal binding/cross–linking sites, while collagen domains may confer self–assembly on all parts of the structure. A graded axial distribution of flanking modules is expected to moderate stress concentration in joined materials having disparate moduli.
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Zeitlinger, J., e D. Bohmann. "Thorax closure in Drosophila: involvement of Fos and the JNK pathway". Development 126, n.º 17 (1 de setembro de 1999): 3947–56. http://dx.doi.org/10.1242/dev.126.17.3947.
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Dorsal closure, a morphogenetic movement during Drosophila embryogenesis, is controlled by the Drosophila JNK pathway, D-Fos and the phosphatase Puckered (Puc). To identify principles of epithelial closure processes, we studied another cell sheet movement that we term thorax closure, the joining of the parts of the wing imaginal discs which give rise to the adult thorax during metamorphosis. In thorax closure a special row of margin cells express puc and accumulate prominent actin fibres during midline attachment. Genetic data indicate a requirement of D-Fos and the JNK pathway for thorax closure, and a negative regulatory role of Puc. Furthermore, puc expression co-localises with elevated levels of D-Fos, is reduced in a JNK or D-Fos loss-of-function background and is ectopically induced after JNK activation. This suggests that Puc acts downstream of the JNK pathway and D-Fos to mediate a negative feed-back loop. Therefore, the molecular circuitry required for thorax closure is very similar to the one directing dorsal closure in the embryo, even though the tissues are not related. This finding supports the hypothesis that the mechanism controlling dorsal closure has been co-opted for thorax closure in the evolution of insect metamorphosis and may represent a more widely used functional module for tissue closure in other species as well.
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Gabarrón, S., M. Gómez, H. Monclús, I. Rodríguez-Roda e J. Comas. "Ragging phenomenon characterisation and impact in a full-scale MBR". Water Science and Technology 67, n.º 4 (1 de fevereiro de 2013): 810–16. http://dx.doi.org/10.2166/wst.2012.633.
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Although there are few studies about clogging phenomenon in the peer-reviewed literature, it is considered one of the main operational challenges by membrane bioreactor (MBR) practitioners. This study presents data from the performance of a full-scale MBR affected by clogging, and ragging in particular. An evaluation of the efficiencies of different applied cleaning methods revealed the acid recovery cleaning to be more efficient than the basic recovery cleanings, although all maintenance cleanings were largely ineffective in recovering membrane permeability. Only declogging cleaning through the manual removal of the accumulated solids was found to be efficient, indicating that such solids were substantially unremoved by chemical cleaning. Moreover, reclogging following manual cleaning demonstrated a propensity for rapid clogging – within a period of 10 days over which the permeability returned to 68 and 88% of the pre-cleaned state. The analysis of the feedwater indicated suspended textile fibres (>70% cotton) to be present at a concentration of more than 40 mg·L−1, ∼90% being smaller than 1 mm (0.06–0.4 mm). These small lengths of filaments evidently pass through pre-treatment and are retained on the membrane surface, forming ‘rags’ within the membrane module, notwithstanding the routine high quality of sludge reflected in the capillary suction time and filterability measurements. Pre-treatment improvement, manual cleaning and permeate flux reduction are the only options to minimise ragging impact over MBR performance.
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Willers, H., P. de Gijsel, N. Ogink, A. D'Amico, E. Martinelli, C. Di Natale, N. van Ras e J. van der Waarde. "Monitoring of biological odour filtration in closed environments with olfactometry and an electronic nose". Water Science and Technology 50, n.º 4 (1 de agosto de 2004): 93–100. http://dx.doi.org/10.2166/wst.2004.0230.
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Air treatment with a compact biological membrane filter, and air quality monitoring with an electronic nose were tested in the laboratory on air from a cage containing six mice. Additional analyses of air to and from the filter were performed using olfactometry and ammonia and hydrogen sulphide gas detection tubes. The biological air filter is a module containing biofilm-coated membrane fibres that separate a closed liquid loop from a gas phase. Odour compounds and oxygen diffuse through the membranes from the gas phase to the biofilm, where they are degraded to carbon dioxide and water. The prototype “ENQBE” electronic nose is based on an array of eight thickness shear mode resonators (TSMR), also known in the literature as quartz microbalance sensors. The chemical sensitivity is given by molecular films of metalloporphyrins and similar compounds. Chemical interaction of compounds in the air with the vibrating sensors induces a frequency change of the vibration that can be measured as a signal. The air from the mouse cage had a strong odour (3490 OUE/m3). The biological membrane filter performed well, achieving over 80% odour and ammonia reduction. The electronic nose signal could be correlated with the inlet and outlet air-quality of the biological filter, making it a promising method for monitoring air quality in closed environments.
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Inferrera, Leandro, Emanuela Aragona, Adam Wylęgała, Antonio Valastro, Gianluigi Latino, Elisa I. Postorino, Romana Gargano, Bogusława Orzechowska-Wylęgała, Edward Wylęgała e Anna M. Roszkowska. "The Role of Hi-Tech Devices in Assessment of Corneal Healing in Patients with Neurotrophic Keratopathy". Journal of Clinical Medicine 11, n.º 6 (14 de março de 2022): 1602. http://dx.doi.org/10.3390/jcm11061602.
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To prove the role of high-tech investigation in monitoring corneal morphological changes in patients with neurotrophic keratopathy (NK) using Keratograph 5M (K5M) and anterior segment OCT (AS-OCT), corneal healing was monitored with Keratograph 5M (Oculus, Wetzlar, Germany) and AS-OCT (DRI, Triton, Topcon, Tokyo, Japan) in 13 patients (8F and 5M), aged from 24 to 93 years (67.8 ± 19) with severe NK, who were treated with Cenegermin 0.002% (20 μg/mL) (Oxervate®, Dompè, Farmaceutici Spa, Milan, Italy). The surface defects were evaluated on Keratograph 5M with ImageJ software and the corneal thickness variations were measured using DRI-Triton OCT software. Instrumental procedures were performed at baseline, and after 4 and 8 weeks of the treatment, respectively. The main outcome measures were reduction of the ulcers’ area and corneal thickness recovery. The mean area of the corneal ulcers was reduced between baseline and 4 weeks examination in all patients, and at 8 weeks all ulcers were completely healed. An increase of the corneal thickness was evidenced between the baseline visit and after the 4- and 8-week follow-up, respectively. Additionally, only in collaborating subjects the In Vivo Confocal Microscopy (IVCM) was performed with HRT Rostock Cornea Module (Heidelberg Eng GmbH) to study the corneal nerves fibres. High-tech diagnostics with K5M, AS-OCT and IVCM proved useful in the assessment of corneal morphology and the healing process in patients with NK and could be extended to assess other corneal pathologies.
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Blobel, Swen, Karin Thielsch, Markus Kaestner e Volker Ulbricht. "Application of Real-Time Photoelastic Analysis to Single Fibre Fragmentation Tests". Applied Mechanics and Materials 24-25 (junho de 2010): 239–44. http://dx.doi.org/10.4028/www.scientific.net/amm.24-25.239.
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One of our main research areas is the trans-scale modelling of damage in composite materials, which consist of a polymer matrix and carbon or glass fibres in different material combinations and geometrical arrangements. From the local stress redistribution in the fibre-matrix interphase and in the surrounding matrix material information on the parameters of microscopic damage models for composite materials can be obtained. Owing to the difficult interface characterisation based on the properties of the single material components, a photoelastic analysis of single fibre fragmentation tests is performed. In addition to the qualitative visual interpretation in polarized light, an enhanced quantitative analysis in combination with digital photoelasticity using a four image phase shifting method will be applied [1]. As the sequential capturing of images might cause incorrect results, these four pictures are grabbed simultaneously. This allows for continuous testing. Additionally, errors due to the relaxation behaviour of the matrix material can be avoided. To this, a modular optical system consisting of a variable long distance microscope and a beam dividing module proposed by [2] was developed. It allows for the simultaneous projection of four different filtered images of one microscopic scene to the four quadrants of a CCD chip. This special equipment gives the possibility to apply quantitative photoelasticity to tensile tests performed on standard testing machines. This paper explains the measurement hardware and discusses the main problems and realised solutions from picture capturing through image processing to real-time photoelastic analysis at the present state of development. Exemplary results for the qualitative analysis of selected material combinations and different manufacturing processes are shown.
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Wong, P. S., B. Ahmed Abdi, J. Mansfield, H. Lopez, J. Moger, I. F. Uchegbu e R. Stratton. "POS0842 NON-INVASIVE COHERENT RAMAN IMAGING OF INVOLVED FOREARM SKIN REVEALS ALIGNED COLLAGEN IN DERMIS OF SYSTEMIC SCLEROSIS PATIENTS". Annals of the Rheumatic Diseases 81, Suppl 1 (23 de maio de 2022): 713.1–713. http://dx.doi.org/10.1136/annrheumdis-2022-eular.317.
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BackgroundSystemic sclerosis (SSc) is an immune-mediated connective tissue disease with clinical hallmark of inflammation, vasculopathy and fibrosis resulting in abnormal collagen and intercellular matrix formation in the dermis and internal organ. Skin severity correlates with systemic complications and mortality in SSc.Many skin assessment tools studied do not fulfilled all standards set by OMERACT which include criterion validity, construct validity, discrimination, responsiveness, reliability and feasibility.Modified Rodnan skin score (mRSS) is commonly used as outcome measure in clinical trials of SSc. It is however, limited by inter-rater variability. Studies also showed that skin biopsy samples from body part of SSc patients with clinically normal mRSS had demonstrable pathological deposition of collagen. While repeat skin biopsy to track longitudinally, may be unacceptable to patients. Hence, ongoing research for non-invasive tools are encouraged.ObjectivesWe follow through our previous work studying commercially available non-invasive imaging tools in SSc skin assessment by using Coherent-Raman scattering microscopy (CRS).MethodsSkin biopsies of 4mm were obtained from SSc (n=3) and HC (n=1). Skin samples were collected at anterior surface of forearm from newly diagnosed diffuse SSc which were treatment naïve. Samples were frozen at -80c prior to analysis under CRS at skin depth of 150-200um. The laser setting was 3% pump (802nm) and 6% stokes (1045nm) to avoid tissue burn. 3 contrast methods used are Coherent anti-Stokes Raman scattering (CARS) for imaging of lipids, Second Harmonic Generation (SHG) for collagen and Two-Photon Fluorescence (TPF) for elastin fibers. We analysed collagen and elastin fibers in the skin samples which is disease relevant end products of fibroblast activation in SSc. Descriptive study of the skin CRS characteristics is reported.ResultsThe SHG analysis revealed denser collagen fibers in dermal layer of diseased skin. It also appears that the collagen deposition occurs in more superficial layers of the skin. Peak of collagen curve were at depth of 110-130um HC vs 75-90um in SSc. Collagen fibres were more aligned in the SSc (Figure 1).Figure 1.Microscopy analysis of SSc (B) vs HC (A) skin. I: 3D image of biopsy samples with three contrasts. Red is CARS for lipid, blue is SHG for collagen and green is TPF for elastin fibers. II. SHG. Imaging revealed denser and more aligned collagen fibers in SSc.Furthermore, TPF revealed larger number of disordered elastin fibres in the dermal layer of SSc than HC.ConclusionNailfold capillaroscopy is used to define and stage micro-vasculopathy in SSc. Inflammatory pro-fibrotic processes on the other hand cause abnormal collagen and intercellular matrix formation in the dermis and internal organ.With the demand of better tools in diagnosis of early SSc and therapeutic research, our work with CRS prove better in objective evaluation of skin changes at the molecular level. Here, we demonstrate that the SHG is altered in the early diffuse SSc skin with increased and aligned collagen in the SSc dermis compatible with mRSS score. Others have observed this alignment of the collagen, and we have published that SSc fibroblasts migrate/invade along aligned collagen and modify the underlying extracellular matrix, adding collagens I and III, cross-linking enzymes and other factors including TSP-1.Our future work include:1.Generating a computer module in defining pathological collagen level2.Analysis of metabolites and pathological pathways in SSc3.In-vivo trials with novel therapeutic peptides.4.Lastly, manufacturing of non-invasive handheld device that is capable of diagnosis subclinical SSc and for outcome measure in clinical-therapeutic researchReferences[1]Abignano G, et al. Virtual skin biopsy by optical coherence tomography: the first quantitative imaging biomarker for scleroderma. Ann Rheum Dis. 2013[2]Ahmed Abdi B, et.al. Use of Patterned Collagen Coated Slides to Study Normal and Scleroderma Lung Fibroblast Migration. Sci Rep. 2017AcknowledgementsWe want to acknowledge our colleagues and patients in Royal Free Hospital, to make this project a success.Disclosure of InterestsNone declared
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BIGOURD, Damien, e Coralie FOURCADE-DUTIN. "Sources paramétriques à base de fibres creuses". Optique Photonique, maio de 2023. http://dx.doi.org/10.51257/a-v1-in410.
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Ramli, Rosdianah, e Nurmin Bolong. "SURFACE WATER TREATMENT BY CUSTOM-MADE MOBILE WATER TREATMENT SYSTEM". Jurnal Teknologi 78, n.º 12 (28 de novembro de 2016). http://dx.doi.org/10.11113/jt.v78.10048.
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Advances in membrane technology have stimulated a growing interest in the development of mobile water treatment systems for rural areas lacking clean water access. This study explored the use of ultrafiltration hollow fibre (UF-HF) membranes as a filter medium in a mobile water system for surface water treatment. Prior to the surface water treatment operation, two types of UF-HF modules were prepared using different numbers of fibres (i.e. 15 and 30 fibres). By considering the effect of turbidity on the membrane permeate flux, it was found that the 30-fibre module performed with higher consistency than the module with 15 fibres within the same range of turbidity. It was observed that the specific permeate flux decreased gradually with operation time and that, simultaneously, specific permeate flux was governed by transmembrane pressure and feed water temperature. Consequently, the filtered water production was found to decrease with time. The UF-HF membrane module demonstrated good surface water treatment efficiency for a smaller-scale filter module and was able to improve surface water from water quality index (WQI) Class III to Class II.