Articles de revues : « Degrade Structures »

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Kumari, Alka, Doongar R. Chaudhary et Bhavanath Jha. « Marine microbe with potential to adhere and degrade plastic structures ». Canadian Journal of Biotechnology 1, Special Issue (5 octobre 2017) : 130. http://dx.doi.org/10.24870/cjb.2017-a116.

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Fu, Yuhua, Ningxie Chen, Ziying Wang, Shouqing Luo, Yu Ding et Boxun Lu. « Degradation of lipid droplets by chimeric autophagy-tethering compounds ». Cell Research 31, n^o 9 (8 juillet 2021) : 965–79. http://dx.doi.org/10.1038/s41422-021-00532-7.

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AbstractDegrading pathogenic proteins by degrader technologies such as PROTACs (proteolysis-targeting chimeras) provides promising therapeutic strategies, but selective degradation of non-protein pathogenic biomolecules has been challenging. Here, we demonstrate a novel strategy to degrade non-protein biomolecules by autophagy-tethering compounds (ATTECs), using lipid droplets (LDs) as an exemplar target. LDs are ubiquitous cellular structures storing lipids and could be degraded by autophagy. We hypothesized that compounds interacting with both the LDs and the key autophagosome protein LC3 may enhance autophagic degradation of LDs. We designed and synthesized such compounds by connecting LC3-binding molecules to LD-binding probes via a linker. These compounds were capable of clearing LDs almost completely and rescued LD-related phenotypes in cells and in two independent mouse models with hepatic lipidosis. We further confirmed that the mechanism of action of these compounds was mediated through LC3 and autophagic degradation. Our proof-of-concept study demonstrates the capability of degrading LDs by ATTECs. Conceptually, this strategy could be applied to other protein and non-protein targets.

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De Gasperi, R., S. al Daher, B. G. Winchester et C. D. Warren. « Substrate specificity of the bovine and feline neutral α-mannosidases ». Biochemical Journal 286, n^o 1 (15 août 1992) : 55–63. http://dx.doi.org/10.1042/bj2860055.

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Neutral alpha-mannosidases were prepared from bovine and cat liver. The activities were distinguished from lysosomal and Golgi alpha-mannosidases by their neutral pH optima, relatively low Km for their synthetic substrate p-nitrophenyl alpha-D-mannoside, inhibition by Zn2+ and absence of inhibition by Co2+, EDTA, low concentrations of swainsonine, or deoxymannojirimycin. The cytosolic alpha-mannosidases were not retained by concanavalin A-Sepharose. They were able to degrade efficiently a variety of oligosaccharides with structures corresponding to certain high-mannose glycans or the oligomannosyl parts of hybrid and complex glycans. However, unlike lysosomal alpha-mannosidases from the same species these enzymes were not able to degrade Man9GlcNAc2 efficiently, and the bovine neutral alpha-mannosidase was not able to degrade a hexasaccharide with a structure analogous to Man5GlcNAc2-PP-dolichol. Sharp differences were noted for the bovine and cat enzymes with regard to the specificity of degradation. The bovine neutral alpha-mannosidase degraded the substrates by defined pathways, but the cat neutral alpha-mannosidase often produced complex mixtures of products, especially from the larger oligosaccharides. Therefore the bovine enzyme resembled the rat and human cytosolic alpha-mannosidases, but the cat enzyme did not. The bovine and cat neutral alpha-mannosidases, unlike the corresponding lysosomal activities, did not show specificity for the hydrolysis of the (1----3)- and (1----6)-linked mannose residues in the N-linked glycan pentasaccharide core.

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Álvarez-Barragán, Joyce, Lilianha Domínguez-Malfavón, Martín Vargas-Suárez, Ricardo González-Hernández, Guillermo Aguilar-Osorio et Herminia Loza-Tavera. « Biodegradative Activities of Selected Environmental Fungi on a Polyester Polyurethane Varnish and Polyether Polyurethane Foams ». Applied and Environmental Microbiology 82, n^o 17 (17 juin 2016) : 5225–35. http://dx.doi.org/10.1128/aem.01344-16.

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ABSTRACTPolyurethane (PU) is widely used in many aspects of modern life because of its versatility and resistance. However, PU waste disposal generates large problems, since it is slowly degraded, there are limited recycling processes, and its destruction may generate toxic compounds. In this work, we isolated fungal strains able to grow in mineral medium with a polyester PU (PS-PU; Impranil DLN) or a polyether PU (PE-PU; Poly Lack) varnish as the only carbon source. Of the eight best Impranil-degrading strains, the six best degraders belonged to theCladosporium cladosporioidescomplex, including the speciesC. pseudocladosporioides,C. tenuissimum,C. asperulatum, andC. montecillanum, and the two others were identified asAspergillus fumigatusandPenicilliumchrysogenum. The best Impranil degrader,C. pseudocladosporioidesstrain T1.PL.1, degraded up to 87% after 14 days of incubation. Fourier transform infrared (FTIR) spectroscopy analysis of Impranil degradation by this strain showed a loss of carbonyl groups (1,729 cm−1) and N—H bonds (1,540 and 1,261 cm−1), and gas chromatography-mass spectrometry (GC-MS) analysis showed a decrease in ester compounds and increase in alcohols and hexane diisocyanate, indicating the hydrolysis of ester and urethane bonds. Extracellular esterase and low urease, but not protease activities were detected at 7 and 14 days of culture in Impranil. The best eight Impranil-degrading fungi were also able to degrade solid foams of the highly recalcitrant PE-PU type to different extents, with the highest levels generating up to 65% of dry-weight losses not previously reported. Scanning electron microscopy (SEM) analysis of fungus-treated foams showed melted and thinner cell wall structures than the non-fungus-treated ones, demonstrating fungal biodegradative action on PE-PU.IMPORTANCEPolyurethane waste disposal has become a serious problem. In this work, fungal strains able to efficiently degrade different types of polyurethanes are reported, and their biodegradative activity was studied by different experimental approaches. Varnish biodegradation analyses showed that fungi were able to break down the polymer in some of their precursors, offering the possibility that they may be recovered and used for new polyurethane synthesis. Also, the levels of degradation of solid polyether polyurethane foams reported in this work have never been observed previously. Isolation of efficient polyurethane-degrading microorganisms and delving into the mechanisms they used to degrade the polymer provide the basis for the development of biotechnological processes for polyurethane biodegradation and recycling.

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Cao, Xian, Feng Gu, Hui Wang, Zhou Fang et Xian-ning Li. « The degradation of azo dye with different cathode and anode structures in biofilm electrode reactors ». RSC Advances 7, n^o 27 (2017) : 16854–60. http://dx.doi.org/10.1039/c7ra00108h.

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Wang, Jiawei, Guanhua Zhang, Jinliang Liu et Yanmin Jia. « Research on destructive test of pretensioning prestressed concrete hollow slab in service ». International Journal of Structural Integrity 9, n^o 4 (13 août 2018) : 429–41. http://dx.doi.org/10.1108/ijsi-07-2017-0043.

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Purpose During service period, the bridge structures will be affected by the environment and load, so the carrying capacity will decline. The purpose of this paper is to research on the bearing capacity of bridge structures with time. Design/methodology/approach Destructive test and non-linear finite element analysis are carried out by utilizing two pretensioning prestressed concrete hollow slabs in service for 20 years; using the structural test deflection value to simulate the stiffness degradation of the service bridge and the finite element calculation results verify the accuracy of the calculation. Findings The flexural rigidity of the main beam when the test beam is destructed is degraded to approximately 20 percent of that before the test, which agrees well with the result of finite element analysis and indicates that the method of deducing the flexural rigidity of the structure according to the measured deflection value can effectively simulate the rigidity degradation law of the bridge in service. The crack resistance property of the test beam degrades obviously and the ultimate bearing capacity of the bending resistance does not degrade obviously. Originality/value The research results truly reflect the destruction process, destructive form, bearing capacity and rigidity degradation law of the old beam of the concrete bridge in service for 20 years and can provide technical basis for optimization design of newly built bridges of the same type and maintenance and reinforcement design of existing old bridges.

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Xiao, Mei-Sheng, et Jeremy E. Wilusz. « An improved method for circular RNA purification using RNase R that efficiently removes linear RNAs containing G-quadruplexes or structured 3′ ends ». Nucleic Acids Research 47, n^o 16 (3 juillet 2019) : 8755–69. http://dx.doi.org/10.1093/nar/gkz576.

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AbstractThousands of eukaryotic protein-coding genes generate circular RNAs that have covalently linked ends and are resistant to degradation by exonucleases. To prove their circularity as well as biochemically enrich these transcripts, it has become standard in the field to use the 3′-5′ exonuclease RNase R. Here, we demonstrate that standard protocols involving RNase R can fail to digest >20% of all highly expressed linear RNAs, but these shortcomings can largely be overcome. RNAs with highly structured 3′ ends, including snRNAs and histone mRNAs, are naturally resistant to RNase R, but can be efficiently degraded once a poly(A) tail has been added to their ends. In addition, RNase R stalls in the body of many polyadenylated mRNAs, especially at G-rich sequences that have been previously annotated as G-quadruplex (G4) structures. Upon replacing K+ (which stabilizes G4s) with Li+ in the reaction buffer, we find that RNase R is now able to proceed through these sequences and fully degrade the mRNAs in their entirety. In total, our results provide important improvements to the current methods used to isolate circular RNAs as well as a way to reveal RNA structures that may naturally inhibit degradation by cellular exonucleases.

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Deschamps, A. M. « Évaluation de la dégradation de deux types de tanin condensé par des bactéries isolées d'écorces en décomposition ». Canadian Journal of Microbiology 31, n^o 5 (1 mai 1985) : 499–502. http://dx.doi.org/10.1139/m85-092.

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Forty-eight bacterial strains isolated from decaying bark were cultivated in a mineral medium with added quebracho and mimosa tannin extracts as carbon sources. The degradation of the two condensed tannins by each bacterial strain was compared by means of two dosage methods permitting estimations of the astringent capacity losses and the attack of the flavane-3-ols groups. For an even incubation period, tannin from mimosa was more strongly degraded than that from quebracho, and depolymerization was much more important than the attack of monomeric structures. These results confirmed the aptitude of those bacteria to degrade condensed tannins, and thus practical utilisation can be foreseen for such strains.[Translated by the journal]

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Jing, Yanqiu, Qiang Lei, Chun Xia, Yu Guan, Yide Yang, Jixian He, Yang Yang, Yonghui Zhang et Min Yan. « Synthesis of Ag and AgCl co-doped ZIF-8 hybrid photocatalysts with enhanced photocatalytic activity through a synergistic effect ». RSC Advances 10, n^o 2 (2020) : 698–704. http://dx.doi.org/10.1039/c9ra10100d.

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Recently, Ag/AgCl composites with different structures have been widely studied and used as photocatalysts to degrade dye pollutants, due to their high separation efficiency of electron–hole pairs under visible light irradiation.

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Xiao, Zi Jun, Rui Qian Qi, Fang Fang Huo, Yun Ling Huang, Hai Xu et Jian R. Lu. « Co-Biodegradation of Multiple Monocyclic Phenolic Compounds by a Novel 2,3-Xylenol-Degrading Pseudomonas Isolate ». Advanced Materials Research 354-355 (octobre 2011) : 1329–32. http://dx.doi.org/10.4028/www.scientific.net/amr.354-355.1329.

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Monocyclic phenolic compounds (MCPCs) from petroleum and coal sources mainly include phenol, cresols, and xylenols. A newly isolated 2,3-xylenol-degrading strain,Pseudomonassp. XQ23, was found to be capable of degrading up to 10 MCPCs for the first time. Addition of easy-to-degrade MCPCs such as phenol and cresols helped decompose hard-to-degrade xylenols and the sequential digestion of the phenolic substrates was highly dependent on their molecule structures. The action on multiple MCPCs by the new isolate XQ23 from this work revealed useful clues on the co-biodegradation of multiple pollutants.

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do Canto, Vanessa Petry, Claudia Elizabeth Thompson et Paulo Augusto Netz. « Polyurethanases : Three-dimensional structures and molecular dynamics simulations of enzymes that degrade polyurethane ». Journal of Molecular Graphics and Modelling 89 (juin 2019) : 82–95. http://dx.doi.org/10.1016/j.jmgm.2019.03.001.

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Duque-Magalhães, M. C., et P. Régnier. « Discrimination of distinct proteinases at the four structural levels of rat liver mitochondria ». Biochemical Journal 233, n^o 1 (1 janvier 1986) : 283–86. http://dx.doi.org/10.1042/bj2330283.

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Rat liver mitochondrial fractions corresponding to four morphological structures (matrix, inner membrane, intermembrane space and outer membrane) contain proteinases that cleave casein components at different rates. Proteinases of the intermembrane space preferentially cleave kappa-casein, whereas the proteinases of the outer membrane, inner membrane and matrix fractions degrade alpha S1-casein more rapidly. Electrophoretic separation of the degradation products of alpha S1-casein and kappa-casein in polyacrylamide gels shows that different polypeptides are produced when the substrate is degraded by the matrix, by both membranes and by the intermembrane-space fraction. Some of the degradation products resulting from incubation of the caseins with the mitochondrial fractions are probably the result of digestion by contaminating lysosomal proteinase(s). The matrix has a high peptidase activity, since glucagon, a small peptide, is very rapidly degraded by this fraction. These observations strongly suggest that distinct proteinases, with different specificities, are associated respectively with the intermembrane space and with both membrane fractions.

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Arnosti, C., M. Wietz, T. Brinkhoff, J. H. Hehemann, D. Probandt, L. Zeugner et R. Amann. « The Biogeochemistry of Marine Polysaccharides : Sources, Inventories, and Bacterial Drivers of the Carbohydrate Cycle ». Annual Review of Marine Science 13, n^o 1 (3 janvier 2021) : 81–108. http://dx.doi.org/10.1146/annurev-marine-032020-012810.

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Polysaccharides are major components of macroalgal and phytoplankton biomass and constitute a large fraction of the organic matter produced and degraded in the ocean. Until recently, however, our knowledge of marine polysaccharides was limited due to their great structural complexity, the correspondingly complicated enzymatic machinery used by microbial communities to degrade them, and a lack of readily applied means to isolate andcharacterize polysaccharides in detail. Advances in carbohydrate chemistry, bioinformatics, molecular ecology, and microbiology have led to new insights into the structures of polysaccharides, the means by which they are degraded by bacteria, and the ecology of polysaccharide production and decomposition. Here, we survey current knowledge, discuss recent advances, and present a new conceptual model linking polysaccharide structural complexity and abundance to microbially driven mechanisms of polysaccharide processing. We conclude by highlighting specific future research foci that will shed light on this central but poorly characterized component of the marine carbon cycle.

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Kanny, K., et V. K. Moodley. « Characterization of Polypropylene Nanocomposite Structures ». Journal of Engineering Materials and Technology 129, n^o 1 (13 juin 2006) : 105–12. http://dx.doi.org/10.1115/1.2400264.

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This study describes the synthesis, mechanical properties, and morphology of nanophased polypropylene structures. The structures were manufactured by melt-blending low weight percentages of montmorillonite nanoclays and polypropylene thermoplastic. Both virgin and infused polypropylene structures were then subjected to quasi-static tensile, flexural, hardness and impact tests. Analysis of test data show that the mechanical properties increase with an increase in nanoclay loading up to a threshold of 2wt.%; thereafter, the material properties degrade. At low weight nanoclay loadings the enhancement of properties is attributed to the lower percolation points created by the high aspect ratio nanoclays. The increase in properties may also be attributed to the formation of intercalated and exfoliated nanocomposite structures formed at these loadings of clay. At higher weight loading, degradation in mechanical properties may be attributed to the formation of agglomerated clay tactoids. Results of transmission electron microscopy studies and scanning electron microscopy studies of the fractured surface of tensile specimens verify these hypotheses.

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Gong, Chunhua, Xianghua Zeng, Chengfeng Zhu, Jiahui Shu, Pingxiu Xiao, Hao Xu, Lichun Liu, Junyong Zhang, Qingdao Zeng et Jingli Xie. « A series of organic–inorganic hybrid materials consisting of flexible organic amine modified polyoxomolybdates : synthesis, structures and properties ». RSC Advances 6, n^o 108 (2016) : 106248–59. http://dx.doi.org/10.1039/c6ra21603j.

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A series of hybrid materials consisting of Tris[(2-pyridyl)methyl]amine modified polyoxomolybdates were obtained and some complexes have efficient photocatalytic activities to degrade pararosaniline hydrochloride dye molecules.

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Leimgruber, Simon, Wolfgang Kern, Roman Hochenauer, Michael Melmer, Armin Holzner et Gregor Trimmel. « RUBBER–BRASS ADHESION LAYER ANALYSIS USING THE OLEFIN-METATHESIS METHOD ». Rubber Chemistry and Technology 88, n^o 2 (1 juin 2015) : 219–33. http://dx.doi.org/10.5254/rct.14.85946.

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ABSTRACT The investigation of the adhesion layer between rubber and brass-coated steel wires is a challenging task due to its strong bonding. We explore the possibilities of olefin-metathesis as a method to degrade the cross-linked rubber network without destroying the adhesion layer. Using a ruthenium catalyst and 1-octene as a co-reactant, different types of rubber—natural rubber, acrylonitrile–butadiene rubber, and styrene–butadiene rubber—can be degraded into soluble fragments. The uncovered adhesion layers can be subsequently analyzed with common analytical methods such as optical microscopy, focusvariation microscopy, and scanning electron microscopy. The revealed surface structures are discussed considering the observed pull-out forces. In a second series, the influence of common additives—cobalt salt, silica, and a resin system—on the metathesis reaction is investigated.

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Gunawan, W., Rildova, N. Yuanita, A. Kurniawan, K. Kahdar et V. Herbenita. « Analysis of Biodegradation Characteristics Based on Visual Observation and Mass Loss Percentage in Soil Burial Test of Sustainable Geo-bag Materials as Temporary Structures in Natural Coastal Protection System ». IOP Conference Series : Earth and Environmental Science 1065, n^o 1 (1 juillet 2022) : 012051. http://dx.doi.org/10.1088/1755-1315/1065/1/012051.

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Abstract Coastal erosion is a significant hazard that causes heavy loss of land and damage to structures in coastal areas globally. To mitigate this problem, coastal engineers worldwide are focusing on sustainable coastal development practices. To this end, many countries are using natural protective methods, including vegetation such as mangroves. However, this practice is not without challenges; to ensure that mangroves could grow strongly required at least two years. A natural coastal protection system is the proposed solution, which combines mangrove vegetation as the main structure and geo-bag-dykes as temporary structures to solve this problem. The role of geo-bag-dykes is needed until mangrove plants mature. So, the length of time for geo-bags to degrade naturally is vital to get considered because otherwise, it will become hazardous coastal debris. Today, commonly used geo-bags are made from synthetic fibers that take a long time to degrade. Thus, this study tested alternative materials made from natural fibers, such as lyocell, kenaf, cotton, and rayon. The objective is to determine whether these alternative materials can be used as sustainable geo-bag materials or not in terms of biodegradation. Based on the soil burial test results contained in ISO 11721-1, these alternative materials degrade much faster when compared to commonly used geo-bag materials.

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Shi, Ji Feng. « Effects of Annealing and Different Substrate Materials on Ohmic Contact Property of IGZO Films ». Applied Mechanics and Materials 423-426 (septembre 2013) : 846–51. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.846.

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Amorphous InGaZnO(a-IGZO) films were deposited on the glass substrates with Al/Mo/ITO films separately using magnetron sputtering and photograph methods,to form resistance structures between a-IGZO films and Al/Mo/ITO films.These samples were annealed in the air and N2 ambience in a series of temperature separately.The results show that regardless of N2 or air ambience,samples annealing at 250 degrade,IGZO films show a good ohmic contact characteristic withAl/Mo/ITOmaterials.And,IGZO films have a better ohmic contact characteristic with ITO/Al than Mo. The transmittance of the IGZO films annealed is better than the transmittance of samples without annealing.And ,the transmittance of samples annealed is rising with the increasing of annealing temperature. Considering the optical and electrical properties of IGZO films, we suggest that 250 centi degrades is a suitable temperature for annealing.

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Mamleeva, N. A., A. N. Kharlanov, M. V. Kuznetsova et D. S. Kosyakov. « Physicochemical Properties of Lignocellulosic Materials from Ozonized Wood ». Журнал физической химии 97, n^o 4 (1 avril 2023) : 580–91. http://dx.doi.org/10.31857/s0044453723040222.

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Lignocellulosic materials (LCMs) obtained after an ozone treatment of pine wood are studied via diffuse reflectance ultraviolet (DRUV) spectroscopy, Raman spectroscopy, and fluorescence spectroscopy. The Raman spectra show that ozonation degrades lignin and hemicelluloses and lowers the content of amorphous cellulose. The Raman spectra of ozonized LCMs are deconvoluted to individual components for the first time. Based on results from analyzing the Raman and DRUV spectra, it is concluded that the aromatic structures of biomass with conjugated –С=С– and С=О bonds simply degrade, while delignification with ozone is accompanied by a multiple increase in the fluorescence of the LCMs. It is shown that the luminescence spectral characteristics of LCMs are governed by the absorption of ozone, allowing us to identify the ranges of ozone consumption corresponding to the dominant degradation of lignin and polysaccharides in the biomaterial.

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Škarvada, Pavel, Robert Macků et Lubomir Skvarenina. « Investigation of Defects at Cu(In,Ga)Se₂ Flexible Solar Cells on Macroscopic and Microscopic Level and their Influence on Solar Cell Performance ». Solid State Phenomena 258 (décembre 2016) : 469–72. http://dx.doi.org/10.4028/www.scientific.net/ssp.258.469.

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This paper investigates imperfection issues of Cu (In,Ga)Se2 thin-film solar cell structures and diagnostic methods of the CIGS solar cells. Electroluminescence and thermography are used to localize defect in macroscopic scale. Microstructures found in defective solar cell area are shown using micrographs. Focused ion beam was used to demonstrate that these structures interfere each solar cell layers. It is shown that micro sized defects (voids) behave as extra-stressed conductive channels that can degrade solar cells in module.

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Wiegand, Tanner, Shweta Karambelkar, Joseph Bondy-Denomy et Blake Wiedenheft. « Structures and Strategies of Anti-CRISPR-Mediated Immune Suppression ». Annual Review of Microbiology 74, n^o 1 (8 septembre 2020) : 21–37. http://dx.doi.org/10.1146/annurev-micro-020518-120107.

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More than 50 protein families have been identified that inhibit CRISPR (clustered regularly interspaced short palindromic repeats)-Cas-mediated adaptive immune systems. Here, we analyze the available anti-CRISPR (Acr) structures and describe common themes and unique mechanisms of stoichiometric and enzymatic suppressors of CRISPR-Cas. Stoichiometric inhibitors often function as molecular decoys of protein-binding partners or nucleic acid targets, while enzymatic suppressors covalently modify Cas ribonucleoprotein complexes or degrade immune signaling molecules. We review mechanistic insights that have been revealed by structures of Acrs, discuss some of the trade-offs associated with each of these strategies, and highlight how Acrs are regulated and deployed in the race to overcome adaptive immunity.

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David Theodore, N., Barbara Vasquez et Peter Fejes. « Microstructural characterization of implanted LOCOS + trench-isolated structures ». Proceedings, annual meeting, Electron Microscopy Society of America 49 (août 1991) : 888–89. http://dx.doi.org/10.1017/s0424820100088750.

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As device dimensions decrease and circuit densities increase, conventional LOCOS (Local-Oxidation of Silicon) isolation presents a limitation due to lateral encroachment of the isolation-oxide. Variations in LOCOS, including poly-buffered LOCOS have been of interest as means to limit lateral encroachment of the field-oxide into the active device-region. Deep-trench isolation provides a means to support device scaling and in this work is integrated with poly-buffered LOCOS to create self-aligned shallow fieldoxide elements with minimal encroachment into active regions. Use of these technologies however requires an understanding of the behavior of the materials and structures being used and their interactions under different processing conditions. The effect of fabrication-related stresses in the structures is of interest because extended-defects, if formed, could electrically degrade devices.

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Bottiglieri, Mélanie, et Christoph Keel. « Characterization of PhlG, a Hydrolase That Specifically Degrades the Antifungal Compound 2,4-Diacetylphloroglucinol in the Biocontrol Agent Pseudomonas fluorescens CHA0 ». Applied and Environmental Microbiology 72, n^o 1 (janvier 2006) : 418–27. http://dx.doi.org/10.1128/aem.72.1.418-427.2006.

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ABSTRACT The potent antimicrobial compound 2,4-diacetylphloroglucinol (DAPG) is a major determinant of biocontrol activity of plant-beneficial Pseudomonas fluorescens CHA0 against root diseases caused by fungal pathogens. The DAPG biosynthetic locus harbors the phlG gene, the function of which has not been elucidated thus far. The phlG gene is located upstream of the phlACBD biosynthetic operon, between the phlF and phlH genes which encode pathway-specific regulators. In this study, we assigned a function to PhlG as a hydrolase specifically degrades DAPG to equimolar amounts of mildly toxic monoacetylphloroglucinol (MAPG) and acetate. DAPG added to cultures of a DAPG-negative ΔphlA mutant of strain CHA0 was completely degraded, and MAPG was temporarily accumulated. In contrast, DAPG was not degraded in cultures of a ΔphlA ΔphlG double mutant. To confirm the enzymatic nature of PhlG in vitro, the protein was histidine tagged, overexpressed in Escherichia coli, and purified by affinity chromatography. Purified PhlG had a molecular mass of about 40 kDa and catalyzed the degradation of DAPG to MAPG. The enzyme had a k cat of 33 s−1 and a Km of 140 μM at 30°C and pH 7. The PhlG enzyme did not degrade other compounds with structures similar to DAPG, such as MAPG and triacetylphloroglucinol, suggesting strict substrate specificity. Interestingly, PhlG activity was strongly reduced by pyoluteorin, a further antifungal compound produced by the bacterium. Expression of phlG was not influenced by the substrate DAPG or the degradation product MAPG but was subject to positive control by the GacS/GacA two-component system and to negative control by the pathway-specific regulators PhlF and PhlH.

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Pegler, Peter, N. David Theodore et Ming Pan. « Formation of defects in implanted hipox-structures ». Proceedings, annual meeting, Electron Microscopy Society of America 50, n^o 2 (août 1992) : 1406–7. http://dx.doi.org/10.1017/s0424820100131668.

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High-pressure oxidation of silicon (HIPOX) is one of various techniques used for electrical-isolation of semiconductor-devices on silicon substrates. Other techniques have included local-oxidation of silicon (LOCOS), poly-buffered LOCOS, deep-trench isolation and separation of silicon by implanted oxygen (SIMOX). Reliable use of HIPOX for device-isolation requires an understanding of the behavior of the materials and structures being used and their interactions under different processing conditions. The effect of HIPOX-related stresses in the structures is of interest because structuraldefects, if formed, could electrically degrade devices.This investigation was performed to study the origin and behavior of defects in recessed HIPOX (RHIPOX) structures. The structures were exposed to a boron implant. Samples consisted of (i) RHlPOX'ed strip exposed to a boron implant, (ii) recessed strip prior to HIPOX, but exposed to a boron implant, (iii) test-pad prior to HIPOX, (iv) HIPOX'ed region away from R-HIPOX edge. Cross-section TEM specimens were prepared in the <110> substrate-geometry.

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Park, Chuntaek, et Ilgu Yun. « Optimization of Self-Heating Driven Leakage Current Properties of Gate-All-Around Field-Effect Transistors Using Neural Network Modeling and Genetic Algorithm ». Electronics 10, n^o 21 (21 octobre 2021) : 2570. http://dx.doi.org/10.3390/electronics10212570.

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As the technology nodes of semiconductor devices have become finer and more complex, progressive scaling down has been implemented to achieve higher densities for electronic devices. Thus, three-dimensional (3D) channel field-effect transistors (FETs), such as fin-shaped FETs (FinFETs) and gate-all-around FETs (GAAFETs), have become popular as they have increased effective surface areas for the channels (Weff), owing to the scaling down strategy. These 3D channel FETs, which have completely covered channel structures with gate oxide and metal, are prone to the self-heating effect (SHE). The SHE is generally known to degrade the on-state drain current; however, when AC pulsed inputs are applied to these devices, the SHE also degrades the off-state leakage current during the off-phase of the pulse. In this study, an optimization methodology to minimize leakage current generation by the SHE is examined.

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Wang, Feng, Qing He, Kaixuan Su, Tiandi Wei, Sujuan Xu et Lichuan Gu. « Structural and biochemical characterization of the catalytic domains of GdpP reveals a unified hydrolysis mechanism for the DHH/DHHA1 phosphodiesterase ». Biochemical Journal 475, n^o 1 (5 janvier 2018) : 191–205. http://dx.doi.org/10.1042/bcj20170739.

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The Asp-His-His and Asp-His-His-associated (DHH/DHHA1) domain-containing phosphodiesterases (PDEs) that catalyze degradation of cyclic di-adenosine monophosphate (c-di-AMP) could be subdivided into two subfamilies based on the final product [5′-phosphadenylyl-adenosine (5′-pApA) or AMP]. In a previous study, we revealed that Rv2837c, a stand-alone DHH/DHHA1 PDE, employs a 5′-pApA internal flipping mechanism to produce AMPs. However, why the membrane-bound DHH/DHHA1 PDE can only degrade c-di-AMP to 5′-pApA remains obscure. Here, we report the crystal structure of the DHH/DHHA1 domain of GdpP (GdpP-C), and structures in complex with c-di-AMP, cyclic di-guanosine monophosphate (c-di-GMP), and 5′-pApA. Structural analysis reveals that GdpP-C binds nucleotide substrates quite differently from how Rv2837c does in terms of substrate-binding position. Accordingly, the nucleotide-binding site of the DHH/DHHA1 PDEs is organized into three (C, G, and R) subsites. For GdpP-C, in the C and G sites c-di-AMP binds and degrades into 5′-pApA, and its G site determines nucleotide specificity. To further degrade into AMPs, 5′-pApA must slide into the C and R sites for flipping and hydrolysis as in Rv2837c. Subsequent mutagenesis and enzymatic studies of GdpP-C and Rv2837c uncover the complete flipping process and reveal a unified catalytic mechanism for members of both DHH/DHHA1 PDE subfamilies.

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Pešata, Michal, Lukáš Procházka, Vlastimil Bilek et Jana Boháčová. « Construction-Technical Survey of the Interspace of an Industrial Chimney ». Solid State Phenomena 322 (9 août 2021) : 209–13. http://dx.doi.org/10.4028/www.scientific.net/ssp.322.209.

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Chimneys are high-rise buildings indispensable for the operation of important plants in industry and in energy. The paper deals with the description and evaluation of defects found on reinforced concrete structures in the chimney interspace. The object of the inspection was a chimney with a reinforced concrete monolithic stem and an offset protective casing. The space between the housing and the stem is ventilated. During the operation of the chimney, aggressive condensate penetrates into the interspace, as a result of which unprotected reinforced concrete structures can degrade.

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Robinson, J. M., J. Chiplonkar et Z. Luo. « A method for co-localization of tubular lysosomes and microtubules in macrophages : fluorescence microscopy of individual cells. » Journal of Histochemistry & ; Cytochemistry 44, n^o 10 (octobre 1996) : 1109–14. http://dx.doi.org/10.1177/44.10.8813075.

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Routinely used procedures for chemical fixation often fail to preserve delicate membrane-bounded tubular structures in a variety of cell types. Fixation procedures commonly employed in immunocytochemical studies for localization of structural proteins, such as those found in cytoskeletal elements, may also degrade these tubular structures. Here we describe a procedure that preserves the elaborate tubular lysosome system found in stimulated macrophages and allows the subsequent immunofluorescence localization of microtubules in the same cells. Use of this methodology permits the assessment of the spatial relationship between tubular lysosomes and microtubules in macrophages.

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Ariyanti, Dessy, Junzhe Dong et Wei Gao. « Hierarchical structures of coated TiO2 nanoribbons with photodegradation and sedimentation properties ». International Journal of Modern Physics B 33, n^o 01n03 (30 janvier 2019) : 1940022. http://dx.doi.org/10.1142/s0217979219400228.

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TiO2 hierarchical structure composed of H2Ti3O7 nanoribbons and TiO2 anatase nanoparticles was synthesized via a two-step hydrothermal process, including the recrystallization of TiO2 precursor into nanoribbons and the subsequent deposition of TiO2 nanoparticles on nanoribbon surface. The coated nanoribbons exhibited a good photocatalytic activity to degrade Rhodamine B (RhB) with a kinetics constant of 0.0269/min, 10 times higher than that of the as-produced nanoribbon (0.0026/min). They also possess good sedimentation properties compared to the pristine TiO2 anatase particles. The excellent photocatalytic performance together with sedimentation property makes these hybrid nanostructures effective and recyclable photocatalysts for wastewater treatment in industrial applications.

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Sandhu, Harleen Kaur, Saran Srikanth Bodda et Abhinav Gupta. « A Future with Machine Learning : Review of Condition Assessment of Structures and Mechanical Systems in Nuclear Facilities ». Energies 16, n^o 6 (10 mars 2023) : 2628. http://dx.doi.org/10.3390/en16062628.

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The nuclear industry is exploring applications of Artificial Intelligence (AI), including autonomous control and management of reactors and components. A condition assessment framework that utilizes AI and sensor data is an important part of such an autonomous control system. A nuclear power plant has various structures, systems, and components (SSCs) such as piping-equipment that carries coolant to the reactor. Piping systems can degrade over time because of flow-accelerated corrosion and erosion. Any cracks and leakages can cause loss of coolant accident (LOCA). The current industry standards for conducting maintenance of vital SSCs can be time and cost-intensive. AI can play a greater role in the condition assessment and can be extended to recognize concrete degradation (chloride-induced damage and alkali–silica reaction) before cracks develop. This paper reviews developments in condition assessment and AI applications of structural and mechanical systems. The applicability of existing techniques to nuclear systems is somewhat limited because its response requires characterization of high and low-frequency vibration modes, whereas previous studies focus on systems where a single vibration mode can define the degraded state. Data assimilation and storage is another challenging aspect of autonomous control. Advances in AI and data mining world can help to address these challenges.

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Liang, Jianze, Chengqi Zhao, Mingxuan Wang, Xipeng Qiu et Lei Li. « Finding Sparse Structures for Domain Specific Neural Machine Translation ». Proceedings of the AAAI Conference on Artificial Intelligence 35, n^o 15 (18 mai 2021) : 13333–42. http://dx.doi.org/10.1609/aaai.v35i15.17574.

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Neural machine translation often adopts the fine-tuning approach to adapt to specific domains. However, nonrestricted fine-tuning can easily degrade on the general domain and over-fit to the target domain. To mitigate the issue, we propose Prune-Tune, a novel domain adaptation method via gradual pruning. It learns tiny domain-specific sub-networks during fine-tuning on new domains. Prune-Tune alleviates the over-fitting and the degradation problem without model modification. Furthermore, Prune-Tune is able to sequentially learn a single network with multiple disjoint domain-specific sub-networks for multiple domains. Empirical experiment results show that Prune-Tune outperforms several strong competitors in the target domain test set without sacrificing the quality on the general domain in both single and multi-domain settings. The source code and data are available at https://github.com/ohlionel/Prune-Tune.

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Ma, X. G., Y. L. Li et L. G. Cao. « Study of g-C3N4/BTO composite photocatalyst with ferroelectric polarization under ultrasound ». Digest Journal of Nanomaterials and Biostructures 18, n^o 4 (20 décembre 2023) : 1529–36. http://dx.doi.org/10.15251/djnb.2023.184.1529.

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Herein, g-C3N4/BTO composite photocatalyst were prepared using melamine, Bi2O3, TiO2, NaCl, and KCl as starting raw materials, and the effect of ferroelectric polarization on photocatalytic properties of g-C3N4/BTO was also investigated. With the increase in the molar percentage of doped BTO samples, the number of square sheet structures has significantly increased, and the tetragonal lamellar structure of BTO samples has further grown, then the wafer size has significantly increased. The degradation performance only degraded less than 20% of RhB under 100 min at the visible light without ultrasound, while, due to the fact that the electric field formed by piezoelectric material is much larger than the defect electric field, which promotes the separation and transmission of carriers, the sample exhibits excellent piezoelectric synergistic photocatalytic effect under ultrasound, especially, g-C3N4/BTO-4 sample can degrade 88.3% of RhB under ultrasound and light conditions within 30 min, demonstrating the potential and huge application of piezoelectric photocatalytic materials

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Sozcu, Sebnem, Mohanapriya Venkataraman, Jakub Wiener, Blanka Tomkova, Jiri Militky et Aamir Mahmood. « Incorporation of Cellulose-Based Aerogels into Textile Structures ». Materials 17, n^o 1 (20 décembre 2023) : 27. http://dx.doi.org/10.3390/ma17010027.

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Given their exceptional attributes, aerogels are viewed as a material with immense potential. Being a natural polymer, cellulose offers the advantage of being both replenishable and capable of breaking down naturally. Cellulose-derived aerogels encompass the replenish ability, biocompatible nature, and ability to degrade naturally inherent in cellulose, along with additional benefits like minimal weight, extensive porosity, and expansive specific surface area. Even with increasing appreciation and acceptance, the undiscovered possibilities of aerogels within the textiles sphere continue to be predominantly uninvestigated. In this context, we outline the latest advancements in the study of cellulose aerogels’ formulation and their diverse impacts on textile formations. Drawing from the latest studies, we reviewed the materials used for the creation of various kinds of cellulose-focused aerogels and their properties, analytical techniques, and multiple functionalities in relation to textiles. This comprehensive analysis extensively covers the diverse strategies employed to enhance the multifunctionality of cellulose-based aerogels in the textiles industry. Additionally, we focused on the global market size of bio-derivative aerogels, companies in the industry producing goods, and prospects moving forward.

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Chekan, Jonathan R., Chayanid Ongpipattanakul, Terry R. Wright, Bo Zhang, J. Martin Bollinger, Lauren J. Rajakovich, Carsten Krebs, Robert M. Cicchillo et Satish K. Nair. « Molecular basis for enantioselective herbicide degradation imparted by aryloxyalkanoate dioxygenases in transgenic plants ». Proceedings of the National Academy of Sciences 116, n^o 27 (17 juin 2019) : 13299–304. http://dx.doi.org/10.1073/pnas.1900711116.

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The synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) is an active ingredient of thousands of commercial herbicides. Multiple species of bacteria degrade 2,4-D via a pathway initiated by the Fe(II) and α-ketoglutarate (Fe/αKG)-dependent aryloxyalkanoate dioxygenases (AADs). Recently, genes encoding 2 AADs have been deployed commercially in herbicide-tolerant crops. Some AADs can also inactivate chiral phenoxypropionate and aryloxyphenoxypropionate (AOPP) herbicides, albeit with varying substrate enantioselectivities. Certain AAD enzymes, such as AAD-1, have expanded utility in weed control systems by enabling the use of diverse modes of action with a single trait. Here, we report 1) the use of a genomic context-based approach to identify 59 additional members of the AAD class, 2) the biochemical characterization of AAD-2 fromBradyrhizobium diazoefficiensUSDA 110 as a catalyst to degrade (S)-stereoisomers of chiral synthetic auxins and AOPP herbicides, 3) spectroscopic data that demonstrate the canonical ferryl complex in the AAD-1 reaction, and 4) crystal structures of representatives of the AAD class. Structures of AAD-1, an (R)-enantiomer substrate-specific enzyme, in complexes with a phenoxypropionate synthetic auxin or with AOPP herbicides and of AAD-2, which has the opposite (S)-enantiomeric substrate specificity, reveal the structural basis for stereoselectivity and provide insights into a common catalytic mechanism.

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Haider, Patrick, Julia B. Kral-Pointner, Julia Mayer, Manuela Richter, Christoph Kaun, Christine Brostjan, Wolf Eilenberg et al. « Neutrophil Extracellular Trap Degradation by Differently Polarized Macrophage Subsets ». Arteriosclerosis, Thrombosis, and Vascular Biology 40, n^o 9 (septembre 2020) : 2265–78. http://dx.doi.org/10.1161/atvbaha.120.314883.

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Objective: Macrophages are immune cells, capable to remodel the extracellular matrix, which can harbor extracellular DNA incorporated into neutrophil extracellular traps (NETs). To study the breakdown of NETs we studied the capability of macrophage subsets to degrade these structures in vitro and in vivo in a murine thrombosis model. Furthermore, we analyzed human abdominal aortic aneurysm samples in support of our in vitro and in vivo results. Approach and Results: Macrophages were seeded onto blood clots or isolated NETs and polarized. All macrophages were capable to degrade NETs. For initial breakdown, macrophages relied on extracellular deoxyribonucleases. Proinflammatory polarization enhanced NET degradation. The boost in degradation was because of increased macropinocytosis, as inhibition by imipramine diminished their NET breakdown. Inhibition of macropinocytosis in a murine thrombosis model led to increased NET burden and reduced thrombus resolution in vivo. When analyzing abdominal aortic aneurysm samples, macrophage density furthermore corresponded negatively with the amount of local NETs in the intraluminal thrombi as well as in the vessel wall, as increased macrophage density was associated with a reduction in NET burden. Conclusions: We provide evidence that macrophages degrade NETs by extracellular predigestion and subsequent uptake. Furthermore, we show that proinflammatory macrophages increase NET degradation through enhanced macropinocytosis, priming them for NET engulfment. Based on our findings, that inhibition of macropinocytosis in mice corresponded to increased NET amounts in thrombi and that local macrophage density in human abdominal aortic aneurysm is negatively associated with surrounding NETs, we hypothesize, that macrophages are able to degrade NETs in vivo.

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Pu, Jia-yi, Jin-quan Wan, Yan Wang et Yong-wen Ma. « Different Co-based MOFs templated synthesis of Co3O4 nanoparticles to degrade RhB by activation of oxone ». RSC Advances 6, n^o 94 (2016) : 91791–97. http://dx.doi.org/10.1039/c6ra15590a.

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Co-MOF with different structures were used as template to prepare Co₃O₄. Then, Co₃O₄ was used to activate oxone for RhB degradation. Finally, templates determine the characteristics of the Co₃O₄, which indirectly affect its catalytic ability.

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Vickackaite, Vida, Aldo Romani, Danilo Pannacci et Gianna Favaro. « Photochemical and thermal degradation of a naturally occurring dye used in artistic painting. A chromatographic, spectrophotometric and fluorimetric study on saffron ». International Journal of Photoenergy 6, n^o 4 (2004) : 175–83. http://dx.doi.org/10.1155/s1110662x04000224.

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Saffron is a yellow substance which is extracted from the stigmas ofCrocus sativus L. and is used in painting, cooking and medicine. In this paper six components (transandciscrocins) with carotenoid structures were separated from natural saffron by HPLC and were characterised by their absorption and emission spectra. Photochemical and thermal processes which degrade the dye were also investigated. The effect of light promoted thecis⇄transisomerization, while the thermal effect detached the glycosyl moieties.

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David Theodore, N., Sam Sundaram et Peter Fejes. « Formation of defects in boron-implanted PEPBLT structures ». Proceedings, annual meeting, Electron Microscopy Society of America 50, n^o 2 (août 1992) : 1408–9. http://dx.doi.org/10.1017/s042482010013167x.

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Variations on LOCOS (local-oxidation of silicon) are being explored for device-isolation, to implement further miniaturization of VLSI devices. One such variation involves poly-encapsulated poly-buffered LOCOS + trench-isolation (PEPBLT). The method provides a means to support device scaling and to create self-aligned shallow field-oxide elements with minimal encroachment into active regions. In an earlier study, dislocations were observed to be associated with a combination of high-dose ∼1E15 cm−2 phosphorus implants and PEPBLT isolation. The present study investigates the effect of boron implants on similar PEPBLT structures. The effect of fabrication-related stresses in the structures is of interest because extended-defects, if formed, could electrically degrade transistors.PEPBLT structures were exposed to varied processing conditions to build high-performance bipolar transistors. Isolated active-device regions from the above structures were characterized using TEM. Some of the active regions were (i) implanted with 80 keV-8.5E15 cm−2 boron with no anneal, (ii) implanted with 80 keV- 8.5E15 cm−2 boron and annealed at 900°C/90’/N2 plus 1050°C/30” RTA during the course of processing, (iii) not implanted.

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Eichfeld, Devon A., Weinan Chen, Ismaila Dabo, Brian M. Foley et Bladimir Ramos-Alvarado. « Thermal rectification in thin film metalattice structures : A computational study ». Journal of Applied Physics 133, n^o 11 (21 mars 2023) : 115101. http://dx.doi.org/10.1063/5.0135963.

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Thermal rectification is an asymmetric heat transfer process where directionally dependent transport occurs along a given axis. In this work, geometric parameters that govern thermal rectification in solids composed of various semiconducting materials were investigated utilizing metalattice data for seven materials with pore sizes ranging between 2 and 30 nm. Using numerical simulation, thermal rectification was calculated at different thermal biases in single material systems, including silicon, cubic boron nitride, and diamond, among others. The largest thermal rectification for each material was exhibited in bilayer sample stacks that were thermally matched (i.e., the thermal resistance of each layer in the stack is equal in either forward or reverse direction). Of the materials tested, diamond provided the highest thermal rectification for all cases, with its best case achieving a thermal rectification of 57.2%. This novel thermal functionality will find application in advanced applications for temperature regulation, including resonator systems where thermal effects may significantly alter and/or degrade performance.

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Wang, Jian-Min, Xin-Yuan Sun et Jian-Ming Ouyang. « Structural Characterization, Antioxidant Activity, and Biomedical Application of Astragalus Polysaccharide Degradation Products ». International Journal of Polymer Science 2018 (30 septembre 2018) : 1–13. http://dx.doi.org/10.1155/2018/5136185.

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To study the antioxidant capacity of Astragalus polysaccharides (APS) with different molecular weights, we used hydrogen peroxide to degrade original Astragalus polysaccharide (APS0) with an initial molecular weight of 11.03 kDa and obtained three degraded polysaccharides with molecular weights of 8.38 (APS1), 4.72 (APS2), and 2.60 kDa (APS3). The structures of these polysaccharides were characterized by 1H NMR, 13C NMR, FT-IR, and GC/MS. The degradation process did not cause significant changes in the main chain structure of APS. The monosaccharide component of APS before and after degradation was slightly changed. The antioxidant ability in vitro (removing hydroxyl and ABTS radicals and reducing ability) and in cells (superoxide dismutase and malondialdehyde generation) of these polysaccharides is closely related to their molecular weight. If the molecular weight of APS is very high or low, it is not conducive to their activity. Only APS2 with moderate molecular weight showed the greatest antioxidant activity and ability to repair human kidney epithelial (HK-2) cells. Therefore, APS2 can be used as a potential antistone polysaccharide drug.

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Kelly, Hannah, Masaki Inada et Yoshifumi Itoh. « The Diverse Pathways for Cell Surface MT1-MMP Localization in Migratory Cells ». Cells 14, n^o 3 (31 janvier 2025) : 209. https://doi.org/10.3390/cells14030209.

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Controlled cell migration is an essential biological process in health, while uncontrolled cell migration contributes to disease progression. For cells to migrate through tissue, they must first degrade the extracellular matrix (ECM), which acts as a physical barrier to cell migration. A type I transmembrane-type matrix metalloproteinase, MT1-MMP, is the key enzyme involved in this process. It has been extensively shown that MT1-MMP promotes the migration of different cell types in tissue, including fibroblasts, epithelial cells, endothelial cells, macrophages, mesenchymal stem cells, and cancer cells. MT1-MMP is tightly regulated at different levels, and its localization to leading-edge membrane structures is an essential process for MT1-MMP to promote cellular invasion. Different cells display different motility-associated membrane structures, which contribute to their invasive ability, and there are diverse mechanisms of MT1-MMP localization to these structures. In this article, we will discuss the current understanding of MT1-MMP regulation, in particular, localization mechanisms to these different motility-associated membrane structures.

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Ohtani, Kazuhiro, et Ryo Okada. « Relationship between classroom social goal structures, gender, and social outcomes in Japanese elementary school children ». School Psychology International 39, n^o 5 (30 juillet 2018) : 435–53. http://dx.doi.org/10.1177/0143034318788120.

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This study examines the interaction between gender and classroom social goal structures and the impact they have on children's prosocial behaviors and classroom adjustment. Specifically, classroom social goal structures (consisting of prosocial and compliance goal structure) are the degree to which focal social goals are presented in classrooms. Numerous previous studies have tested the gender differences in social outcomes; however, the results of such past studies have been mixed, as some detected gender differences while others did not. This suggests the existence of moderator variables. Consequently, in this research, we focused on classroom-level moderators in the relationship between gender and social outcomes. We analysed a sample of 3,609 Japanese public elementary school children from 114 classrooms, and we detected the presence of cross-level interactions and found that classroom social goal structures can promote or degrade boys' social outcomes.

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Li, Yuqi, Zhenxiang Meng, Yao Xu, Qicheng Shi, Yuping Ma, Min Aung, Yanfen Cheng et Weiyun Zhu. « Interactions between Anaerobic Fungi and Methanogens in the Rumen and Their Biotechnological Potential in Biogas Production from Lignocellulosic Materials ». Microorganisms 9, n^o 1 (17 janvier 2021) : 190. http://dx.doi.org/10.3390/microorganisms9010190.

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Anaerobic fungi in the digestive tract of herbivores are one of the critical types of fiber-degrading microorganisms present in the rumen. They degrade lignocellulosic materials using unique rhizoid structures and a diverse range of fiber-degrading enzymes, producing metabolic products such as H2/CO2, formate, lactate, acetate, and ethanol. Methanogens in the rumen utilize some of these products (e.g., H2 and formate) to produce methane. An investigation of the interactions between anaerobic fungi and methanogens is helpful as it provides valuable insight into the microbial interactions within the rumen. During the last few decades, research has demonstrated that anaerobic fungi stimulate the growth of methanogens and maintain methanogenic diversity. Meanwhile, methanogens increase the fiber-degrading capability of anaerobic fungi and stimulate metabolic pathways in the fungal hydrogenosome. The ability of co-cultures of anaerobic fungi and methanogens to degrade fiber and produce methane could potentially be a valuable method for the degradation of lignocellulosic materials and methane production.

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Baibara, O. E., M. V. Radchenko, V. A. Karpyna et A. I. Ievtushenko. « A Review of the some aspects for the development of ZnO based photocatalysts for a variety of applications ». Physics and Chemistry of Solid State 22, n^o 3 (26 septembre 2021) : 585–94. http://dx.doi.org/10.15330/pcss.22.3.585-594.

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Today, one of the most important problems for humanity is the pollution of the environment with various organic compounds that worsen the health of the peoples. The most dangerous pollutants are complex compounds that do not degrade under natural conditions. One way to solve the problem of pollution is to use photocatalysis to degrade harmful compounds. Zinc oxide nanostructures exhibit attractive photocatalytic and antibacterial properties due to the increased reactivity of the nanoparticle surface, which allows the efficient decomposition of organic pollutants. In this review, various methods for enhancing the photoefficiency of ZnO nanostructures are considered. It is shown that ZnO nanoparticles with specific surfaces (spherical, nanowires, nanoflowers), which are characterized by a high surface area, have a high removal rate of various pollutants. Such methods of improving the photocatalytic properties of ZnO as the band gap engineering, doping with metal/nonmetal, the combination of ZnO with other materials, formation of hybrid structures are considered.

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Fitzgerald, E. A. « Cathodoluminescence and electron-beam-induced current investigations of semiconductor materials and structures for optoelectronic integration ». Proceedings, annual meeting, Electron Microscopy Society of America 49 (août 1991) : 832–33. http://dx.doi.org/10.1017/s0424820100088476.

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Mismatched semiconductor heteroepitaxy has been of interest for both high speed electronics and optoelectronic integration. The largest impact of mismatched epitaxy would be the integration of mature Si electronics with light-emitting III-V materials, such as GaAs. However, the lattice constant of Si is much smaller than the lattice constant of direct band gap III-V materials; therefore, integration through epitaxy introduces many misfit-relieving dislocations, which can terminate at the surface (threading dislocation segments). Any optical devices fabricated from this material degrade rapidly due to the high dislocation density. Cathodoluminescence (CL) and electron beam induced current (EBIC) are extremely valuable in relating optoelectronic quality to microstructure and processing.

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Pandey, Krishna K., et Tapani Vuorinen. « UV resonance Raman spectroscopic study of photodegradation of hardwood and softwood lignins by UV laser ». Holzforschung 62, n^o 2 (1 mars 2008) : 183–88. http://dx.doi.org/10.1515/hf.2008.046.

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Abstract The effect of laser irradiation (Ar+ ion laser, 244 nm) on photodegradation of lignin in silver birch and rubberwood as hardwoods and spruce and chir pine as softwoods has been investigated by UV resonance Raman spectroscopy (UVRRS). UVRR spectra showed degradation of aromatic structures accompanied by the formation of both ortho- and para-quinone structures as a result of photodegradation of wood surfaces. There was a rapid decrease in the intensities of all the lignin-associated bands accompanied by broadening of aromatic bands at 1602 cm-1 and in the region of 1500–1000 cm-1 due to formation of unsaturated structures arisen from lignin degradation. The rate of lignin degradation was observed by measuring the relative intensity of aromatic band at 1602 cm-1 during photodegradation. The rates of UV-degradation of hardwood and softwood surfaces were compared and it was found that hardwoods degrade at a faster rate than softwoods. The syringyl structures in hardwood lignin are more sensitive to photochemical degradation than guaiacyl structures. The rate of photodegradation increased with increasing intensity of the irradiated laser energy.

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Abdalla, Aso Akram, et Dr Ferhad Rahim Karim. « Repairing Materials for Different Post Fire - Damaged Structural Concrete Members : A Critical Review ». CONSTRUCTION 2, n^o 2 (11 octobre 2022) : 56–64. http://dx.doi.org/10.15282/construction.v2i2.8660.

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When concrete structures are exposed to elevated temperatures or fire, their strength begins to degrade. The major problem is that the structure induces cracks, which let the aggressive material enter the concrete and the steel reinforcement corrosion. Therefore, the damaged member should have been strengthened or repaired; sometimes, the repair is chosen over demolition because it is more economical. Researchers used materials to repair heat-damaged concrete, such as fiber-reinforced polymer (FRP) composites, shotcrete, ferrocement, epoxy resin mortar, and fiber-reinforced concrete. The compatibility of these materials should be investigated, for example, the bond strength between repair material and substrate. Ferrocement can restore stiffness and toughness, while a structure with FRP jacketing cannot regain stiffness. Reviewing post-fire strength and repairing materials has not been done; therefore, this study highlights the strength loss of fire-damaged concrete and the repaired structure's confinement.

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Fejes, Peter, N. David Theodore et Han-Bin Liang. « Geometry-dependence of defects in PBLT serpentines ». Proceedings, annual meeting, Electron Microscopy Society of America 50, n^o 2 (août 1992) : 1410–11. http://dx.doi.org/10.1017/s0424820100131681.

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Poly-buffered LOCOS + trench-isolation is a technique being explored for device-isolation on semiconductor substrates. The method creates self-aligned shallow field-oxide elements with minimal encroachment into active regions. In an earlier study/dislocations were observed in PBLT structures, associated with a combination of high-dose [∼1E15 cm−2] phosphorus implants and PBLT isolation. The present study investigates the effect of implant- and isolation-geometries on the formation of extended-defects in PBLT structures. The effect of fabrication-related stresses in the structures is of interest because extended-defects, once formed, can electrically degrade devices.PBLT structures were fabricated using varied implant- and isolation- geometries. Selected regions of the structures were exposed to 1E15 cm−2 phosphorus implants. Transmission electron microscopy was then used to characterize these regions. Some of the structures investigated were (i) trench with no adjacent implant, (ii) trench with an adjacent trench, but no implant, (iii) trench with a 1E15 cm−2 phosphorus implant placed ∼4 μm from the trench, (iv) trench with a 1E15 cm−2 phosphorus implant placed ∼2 μm from the trench, (v) doubly-kinked trench with a 1E15cm−2 phosphorus implant placed between the kinks.

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Thi Mo, Luong, Puntus Irina, Suzina Natalia, Nechaeva Irina, Akhmetov Lenar, Filonov Andrey, Akatova Ekaterina, Alferov Sergey et Ponamoreva Olga. « Hydrocarbons Biodegradation by Rhodococcus : Assimilation of Hexadecane in Different Aggregate States ». Microorganisms 10, n^o 8 (8 août 2022) : 1594. http://dx.doi.org/10.3390/microorganisms10081594.

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The aim of our study was to reveal the peculiarities of the adaptation of rhodococci to hydrophobic hydrocarbon degradation at low temperatures when the substrate was in solid states. The ability of actinobacteria Rhodococcus erythropolis (strains X5 and S67) to degrade hexadecane at 10 °C (solid hydrophobic substrate) and 26 °C (liquid hydrophobic substrate) is described. Despite the solid state of the hydrophobic substrate at 10 °C, bacteria demonstrate a high level of its degradation (30–40%) within 18 days. For the first time, we show that specialized cellular structures are formed during the degradation of solid hexadecane by Rhodococcus at low temperatures: intracellular multimembrane structures and surface vesicles connected to the cell by fibers. The formation of specialized cellular structures when Rhodococcus bacteria are grown on solid hexadecane is an important adaptive trait, thereby contributing to the enlargement of a contact area between membrane-bound enzymes and a hydrophobic substrate.

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Jeyakanthan, Jeyaraman, Shankar Prasad Kanaujia, Yuya Nishida, Noriko Nakagawa, Surendran Praveen, Akeo Shinkai, Seiki Kuramitsu, Shigeyuki Yokoyama et Kanagaraj Sekar. « Free and ATP-bound structures of Ap4A hydrolase fromAquifex aeolicusV5 ». Acta Crystallographica Section D Biological Crystallography 66, n^o 2 (22 janvier 2010) : 116–24. http://dx.doi.org/10.1107/s0907444909047064.

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Asymmetric diadenosine tetraphosphate (Ap4A) hydrolases degrade the metabolite Ap4A back into ATP and AMP. The three-dimensional crystal structure of Ap4A hydrolase (16 kDa) fromAquifex aeolicushas been determined in free and ATP-bound forms at 1.8 and 1.95 Å resolution, respectively. The overall three-dimensional crystal structure of the enzyme shows an αβα-sandwich architecture with a characteristic loop adjacent to the catalytic site of the protein molecule. The ATP molecule is bound in the primary active site and the adenine moiety of the nucleotide binds in a ring-stacking arrangement equivalent to that observed in the X-ray structure of Ap4A hydrolase fromCaenorhabditis elegans. Binding of ATP in the active site induces local conformational changes which may have important implications in the mechanism of substrate recognition in this class of enzymes. Furthermore, two invariant water molecules have been identified and their possible structural and/or functional roles are discussed. In addition, modelling of the substrate molecule at the primary active site of the enzyme suggests a possible path for entry and/or exit of the substrate and/or product molecule.

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