Articles de revues : « Lay catalysis »

1

Zhang, Lian Zi, et Hao Yuan Sun. « Development of Catalysts for Synthesizing Methanol from Syngas ». Materials Science Forum 1053 (17 février 2022) : 165–69. http://dx.doi.org/10.4028/p-0eor9r.

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At present, methanol is one of the most basic organic chemical raw materials and energy storage media. With the development of chemical technology and energy storage technology, its application becomes more and more extensive, and the methanol market prospects are unlimited. Industrial-scale methanol is generally prepared by using synthesis gas containing hydrogen, carbon monoxide, and carbon dioxide as raw materials and reacting under a certain pressure, temperature, and catalyst. Therefore, the development of the methanol industry largely depends on the development of catalysts and the improvement of their performance. Metal catalysts are mainly used in the industry for reaction. This article reviews several metal catalysts used to synthesize methanol from syngas. Copper-based and iron-based catalysts are widely used, and the emerging rhodium and its ligand catalysts exhibit good catalytic performance in low-temperature catalysis. In the future, the scientific research team will focus on in-depth research on preparation methods, active centers, catalytic reaction kinetics, durability, metal ligands, raw material prices, etc., to lay a solid foundation for the industrial application of syngas to methanol in advance.

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Poier, Dario, Sharon Mitchell, Victor Tulus, Gonzalo Guillén-Gosálbez, Javier Pérez-Ramírez et Roger Marti. « Aiming for More Sustainable Cross-Coupling Chemistry by Employing Single-Atom Catalysis on Scale ». CHIMIA 77, n^o 3 (29 mars 2023) : 127. http://dx.doi.org/10.2533/chimia.2023.127.

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Scaling up syntheses from mg to kg quantities is a complex endeavor. Besides adapting laboratory protocols to industrial processes and equipment and thorough safety assessments, much attention is paid to the reduction of the process’ environmental impact. For processes including transition metal catalyzed steps, e.g. cross-coupling chemistry, this impact strongly depends on the identity of the metal used. As such, a key approach is the replacement of single-use with reusable heterogeneous catalysts. Transition metal single-atom heterogeneous catalysts (SAC), a novel class of catalytic materials, might exhibit all the necessary properties to step up to this task. This article shall discuss current applications of SAC in cross-coupling chemistry from the point of a process chemist and shed light on the NCCR Catalysis contribution to the field. Investigations of the stability-activity-selectivity relationship of SACs in combination with early-stage life-cycle assessments (LCA) of potential processes lay the foundation for large-scale application tailored catalyst synthesis. Ultimately, prevailing challenges are highlighted, which need to be addressed in future research.

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García, Pablo, Enrique Lima, Julia Aguilar et Víctor Lara. « Fractal Extra-Framework Species in De-aluminated LaY Zeolites and Their Catalytic Activity ». Catalysis Letters 128, n^o 3-4 (18 novembre 2008) : 385–91. http://dx.doi.org/10.1007/s10562-008-9761-5.

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Zhang, Qian, Qiyu Peng, Wenbin Li, Yanzhang Liu et Xiaoxiong Wang. « Waste Plastic Recycling Upgrade Design Nanogenerator for Catalytic Degradation of Pollutants ». Catalysts 13, n^o 6 (19 juin 2023) : 1019. http://dx.doi.org/10.3390/catal13061019.

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In recent years, electrocatalytic degradation of pollutants based on nanogenerators has gradually emerged. Compared with the huge energy consumption of traditional electrocatalysis, this method can effectively use displacement current to induce charge transfer and complete catalysis, so it can directly use the existing water flow energy and other energy sources in nature. This work will explain the basic principles, methods, and measurement methods of preparing nanogenerators from waste plastics, as well as the classification of electrocatalytic principles and methods relative to nanogenerators, which provides important support for the research in this emerging field. At the same time, the analysis based on this knowledge will also lay the foundation for future design.

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Xu, Jiayi, Jinkui Pi, Yanjing Zhang, Jinhan Zhou, Shuxia Zhang et Sisi Wu. « Effects of Ferroptosis on Cardiovascular Diseases ». Mediators of Inflammation 2023 (4 mai 2023) : 1–11. http://dx.doi.org/10.1155/2023/6653202.

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Ferroptosis is a novel form of programmed cell death characterized by the accumulation of iron-dependent lipid peroxides, which causes membrane injury. Under the catalysis of iron ions, cells deficient in glutathione peroxidase (GPX4) cannot preserve the balance in lipid oxidative metabolism, and the buildup of reactive oxygen species on the membrane lipids leads to cell death. An increasing body of evidence suggests that ferroptosis plays a significant role in the development and occurrence of cardiovascular diseases. In this paper, we mainly elaborated on the molecular mechanisms regulating ferroptosis and its impact on cardiovascular disease to lay the groundwork for future studies on the prophylaxis and treatment of this patient population.

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Bowker, M. « The effect of coke lay-down on n-heptane reforming on Pt and Pt-Sn catalysts ». Applied Catalysis A : General 257, n^o 1 (10 janvier 2004) : 57–65. http://dx.doi.org/10.1016/s0926-860x(03)00613-6.

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Hoyle, Jeffrey, J. Stuart Grossert, Donald L. Hooper et Subramanian Sotheeswaran. « Sulphur-33 nuclear magnetic resonance spectroscopy of sulphones ». Canadian Journal of Chemistry 64, n^o 8 (1 août 1986) : 1581–84. http://dx.doi.org/10.1139/v86-261.

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The sulphur-33 nmr spectra of 28 sulphones were measured in deuterochloroform solutions at 27.716172 MHz. The spectra were referenced with respect to an external aqueous ammonium sulphate solution and the chemical shifts lay in the range 0 ± 20 ppm, with many lines having a half-height width of less than 200 Hz. Instrumental parameters that affect the spectra were studied. Some of the sulphur-33 resonances can be correlated well with carbon-13 or oxygen-17 resonances in appropriate analogous compounds, and with the Taft σ* parameter.

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Aloni, Sapir Shekef, Molhm Nassir et Yitzhak Mastai. « Chiral Porous Carbon Surfaces for Enantiospecific Synthesis ». Polymers 14, n^o 14 (6 juillet 2022) : 2765. http://dx.doi.org/10.3390/polym14142765.

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Chiral surfaces, developed in the last decade, serve as media for enantioselective chemical reactions. Until today, they have been based mostly on developments in silica templating, and are made mainly from imprints of silicate materials developed a long time ago. Here, a chiral porous activated carbon surface was developed based on a chiral ionic liquid, and the surface chemistry and pore structure were studied to lay a new course of action in the field. The enantioselectivities of surfaces are examined by using variety of methods such as circular dichroism, linear sweep voltammetry and catalysis. These techniques revealed a 28.1% preference for the D enantiomer of the amino acid proline, and linear sweep voltammetry confirmed chirality recognition by another probe. An aldol surface chiral catalytic reaction was devised and allowed to determine the root of the enantiomeric excess. These results affirm the path toward a new type of chiral surface.

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Cong, Fangdi, Hongzhen Jiang, Xiguang Du, Shulin Zhang et Wei Yang. « Facile, Mild-Temperature Synthesis of Metal-Free Phthalocyanines ». Synthesis 53, n^o 15 (5 mai 2021) : 2656–64. http://dx.doi.org/10.1055/a-1499-8865.

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AbstractIt is important for the synthesis and research of phthalocyanine compounds for these compounds to be easily obtained at low temperature. We observed that metal-free phthalocyanine was sometimes found in a simple system used to synthesize phthalocyanine precursors at room temperature, and further studies showed that the key to the effective formation of phthalocyanines at low temperature lay in the presence of equal volumes of alcohol and amine, in addition to substrate phthalonitriles and solvents, in the reaction system. A synthetic mechanism was proposed and facile syntheses have been realized, such as the synthesis of tetra-α(β)-nitrophthalocyanines and tetra-α(β)-(4-tert-butylphenoxy)phthalocyanines from the corresponding substituted phthalonitriles at mild temperature (37 °C). The results are significant for the design and synthesis of new phthalocyanine derivatives, and the method is convenient and easy to adopt for general use in standard laboratories.

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Rizkin, Benjamin A., et Ryan L. Hartman. « Activation of homogenous polyolefin catalysis with a machine-assisted reactor laboratory-in-a-box (μAIR-LAB) ». Reaction Chemistry & ; Engineering 5, n^o 8 (2020) : 1450–60. http://dx.doi.org/10.1039/d0re00139b.

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Catalysis discovery is typically limited to specialized labs – this work demonstrates an Artificially Intelligent Microreactor Lab in a Box applied to investigate the chemistry of different co-catalysts for zirconocene-catalyzed olefin polymerization.

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Abdallah, Dalia, Mohmad Asri Abd Ghani, Michael F. Cunningham, Peter M. Kazmaier, Barkev Keoshkerian et Erwin Buncel. « Multi-armed, TEMPO-functionalized unimolecular initiators for starburst dendrimer synthesis via stable free radical polymerization. 1. Tri azo-functionalized unimer ». Canadian Journal of Chemistry 82, n^o 9 (1 septembre 2004) : 1393–402. http://dx.doi.org/10.1139/v04-107.

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The synthesis of azobenzene-functionalized multi-armed unimolecular initiators or "unimers" that can be polymerized using styrene or styrenic derivatives via TEMPO (2,2,6,6-tetramethylpiperidenyl-1-oxyl) mediated stable free radical polymerization (SFRP) is described. The unimers are composed of an azobenzene-functionalized core and a TEMPO-modified unit. Homopolymers and copolymers of styrene and acetoxystyrene were synthesized using the mono-and trifunctionalized unimers as initiators under bulk conditions with average molecular weights and polydispersities reported. The studies lay the groundwork for further investigations involving SFRP towards building a light harvesting system by introducing chromophores onto the polymer chains for capturing light and thence transferring it to the azobenzene core.Key words: azo-functionalized unimolecular initiator, stable free radical polymerization, starburst dendrimer.

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Langton, Michelle, Sining Sun, Chie Ueda, Max Markey, Jiahua Chen, Isaac Paddy, Paul Jiang, Natalie Chin, Amy Milne et Maria-Eirini Pandelia. « The HD-Domain Metalloprotein Superfamily : An Apparent Common Protein Scaffold with Diverse Chemistries ». Catalysts 10, n^o 10 (15 octobre 2020) : 1191. http://dx.doi.org/10.3390/catal10101191.

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The histidine–aspartate (HD)-domain protein superfamily contains metalloproteins that share common structural features but catalyze vastly different reactions ranging from oxygenation to hydrolysis. This chemical diversion is afforded by (i) their ability to coordinate most biologically relevant transition metals in mono-, di-, and trinuclear configurations, (ii) sequence insertions or the addition of supernumerary ligands to their active sites, (iii) auxiliary substrate specificity residues vicinal to the catalytic site, (iv) additional protein domains that allosterically regulate their activities or have catalytic and sensory roles, and (v) their ability to work with protein partners. More than 500 structures of HD-domain proteins are available to date that lay out unique structural features which may be indicative of function. In this respect, we describe the three known classes of HD-domain proteins (hydrolases, oxygenases, and lyases) and identify their apparent traits with the aim to portray differences in the molecular details responsible for their functional divergence and reconcile existing notions that will help assign functions to yet-to-be characterized proteins. The present review collects data that exemplify how nature tinkers with the HD-domain scaffold to afford different chemistries and provides insight into the factors that can selectively modulate catalysis.

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Wang, Jia-Qi, Zhen-Yu Zuo et Wei He. « Recent Advances of Green Catalytic System I2/DMSO in C–C and C–Heteroatom Bonds Formation ». Catalysts 12, n^o 8 (26 juillet 2022) : 821. http://dx.doi.org/10.3390/catal12080821.

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Developing a green, practical and efficient method for the formation of C–C and C–Heteroatom bonds is an important topic in modern organic synthetic chemistry. In recent years, the I2/DMSO catalytic system has attracted wide attention because of its green, high efficiency, atomic economy, low cost, mild reaction conditions and it is environment-friendly, which is more in line with the requirements of sustainable chemistry. Heteroatom-containing compounds have shown lots of important applications in pharmaceutical synthesis, agrochemicals, material chemistry and organic dyes. At present, the I2/DMSO catalytic system has been successfully applied to the synthesis of various heteroatom-containing compounds. The C–C and C–Heteroatom bonds have been formed efficiently, which has been proved to be a green and mild catalytic system. In this review, the research achievements of the I2/DMSO catalytic system in the formation of C–C and C–Heteroatom bonds from 2015 to date are described, and the research area is prospected. This review attempts to reveal the general law of iodine catalysis and lay a foundation for the design of new reactions.

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Biczô, Géza. « From crystal orbitals to strange electronic states. I. Crystal orbitals by direct recursion (transfer matrix) method (DRM) ». Canadian Journal of Chemistry 63, n^o 7 (1 juillet 1985) : 1992–99. http://dx.doi.org/10.1139/v85-330.

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The history of Bloch's and Tamm's states is sketched. The present stage in the theory of the bounded infinite polymers and crystals and strange electronic states is outlined. To lay the foundations of the SCF LCAO bounded crystal orbital (BCO) method applicable for surface electronic problems, the direct recursion (transfer matrix) method (DRM) is formulated for perfect cyclic polymers and crystals. A simple combination of block-decomposition and matrix transpositions is applied to calculate U−1 directly from the blocks of U, the similarity transformation bringing the recursion matrix T into its normal form. Several forms are given for the auxiliary and fundamental equation of the DRM. The crystal orbitals are derived by the DRM. Full matrix expression is presented for the resolvent (Green) matrix of perfect cyclic polymers, the unperturbed system in the SCF local-density approach of Ladik and Seel. The formulae of the charge-bond order matrix are derived both by the DRM and the indirect (Green matrix) recursion method (IRM).

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Nie, Wenjie, Jiao Liu, Xue Bai, Zefeng Xing et Ying Gao. « Designing Phenyl Porous Organic Polymers with High-Efficiency Tetracycline Adsorption Capacity and Wide pH Adaptability ». Polymers 14, n^o 1 (5 janvier 2022) : 203. http://dx.doi.org/10.3390/polym14010203.

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Adsorption is an effective method to remove tetracycline (TC) from water, and developing efficient and environment-friendly adsorbents is an interesting topic. Herein, a series of novel phenyl porous organic polymers (P-POPs), synthesized by one-pot polymerization of different ratios of biphenyl and triphenylbenzene under AlCl3 catalysis in CH2Cl2, was studied as a highly efficient adsorbent to removal of TC in water. Notably, the obtained POPs possessed abundant phenyl-containing functional groups, large specific surface area (1098 m2/g) with abundant microporous structure, high pore volume (0.579 cm3/g), favoring the removal of TC molecules. The maximum adsorption capacity (fitted by the Sips model) could achieve 581 mg/g, and the adsorption equilibrium is completed quickly within 1 h while obtaining excellent removal efficiency (98%). The TC adsorption process obeyed pseudo-second-order kinetics and fitted the Sips adsorption model well. Moreover, the adsorption of POPs to TC exhibited a wide range of pH (2–10) adaptability and outstanding reusability, which could be reused at least 5 times without significant changes in structure and efficiency. These results lay a theoretical foundation for the application of porous organic polymer adsorbents in antibiotic wastewater treatment.

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Xinyu Zhang, Xinyu Zhang, Jiajun Li Jiajun Li, Ming Guo Ming Guo, Kaijie Ni Kaijie Ni et Ronghui Wu and Zhiyan Hu Ronghui Wu and Zhiyan Hu. « Electrocatalytic Oxidation Performance of PbO2 Composite Electrode Doped with MXenes ». Journal of the chemical society of pakistan 45, n^o 3 (2023) : 189. http://dx.doi.org/10.52568/001247/jcsp/45.03.2023.

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In this study, a two-dimensional transition metal carbon/nitride (MXenes) method was used to enhance the electrocatalytic oxidation behavior of PbO2 electrode. A novel composite electrode was prepared by doping the modified MXenes into PbO2 material. The electrochemical performance was tested by electrochemical workstation. The typical cationic red X-GRL was treated by electrochemical oxidation, and the electrochemical oxidation performance of the material electrode was investigated. The results demostrated that the dyes were removed by the oxygen evolution reaction at the electrodes doped with modified MXenes by passing current. The charge transfer resistance is 12.56. The electrodes have remained stable after 20 cycles of charging and discharging. And the removal rate of cationic red X-GRL was as high as 95.19% in 120 min. A high-efficiency composite electrode was developed in this study, which increased the electrodeand#39;s performance as well as wastewater degradation efficiency, and lay the groundwork for future research into doping MXenes to improve the performance of other materials. Hence, electrode materials doped with two-dimensional structured MXenes were candidates for the removal of contaminants, especially in the field of electrochemical catalysis

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PIKUS, S. « Changes in dispersion of platinum deposited on LaY and CeY during heating at high temperatures in oxygen, hydrogen, carbon dioxide, and water vapour ». Journal of Catalysis 136, n^o 2 (août 1992) : 334–41. http://dx.doi.org/10.1016/0021-9517(92)90066-q.

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Nobile, Concetta, et Pantaleo Davide Cozzoli. « Synthetic Approaches to Colloidal Nanocrystal Heterostructures Based on Metal and Metal-Oxide Materials ». Nanomaterials 12, n^o 10 (18 mai 2022) : 1729. http://dx.doi.org/10.3390/nano12101729.

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Composite inorganic nanoarchitectures, based on combinations of distinct materials, represent advanced solid-state constructs, where coexistence and synergistic interactions among nonhomologous optical, magnetic, chemical, and catalytic properties lay a basis for the engineering of enhanced or even unconventional functionalities. Such systems thus hold relevance for both theoretical and applied nanotechnology-based research in diverse areas, spanning optics, electronics, energy management, (photo)catalysis, biomedicine, and environmental remediation. Wet-chemical colloidal synthetic techniques have now been refined to the point of allowing the fabrication of solution free-standing and easily processable multicomponent nanocrystals with sophisticated modular heterostructure, built upon a programmed spatial distribution of the crystal phase, composition, and anchored surface moieties. Such last-generation breeds of nanocrystals are thus composed of nanoscale domains of different materials, assembled controllably into core/shell or heteromer-type configurations through bonding epitaxial heterojunctions. This review offers a critical overview of achievements made in the design and synthetic elaboration of colloidal nanocrystal heterostructures based on diverse associations of transition metals (with emphasis on plasmonic metals) and transition-metal oxides. Synthetic strategies, all leveraging on the basic seed-mediated approach, are described and discussed with reference to the most credited mechanisms underpinning regioselective heteroepitaxial deposition. The unique properties and advanced applications allowed by such brand-new nanomaterials are also mentioned.

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Zhai, Lixin, Zihao Xie, Qiaopeng Tian, Zhengbing Guan, Yujie Cai et Xiangru Liao. « Structural and Functional Analysis of the Only Two Pyridoxal 5′-Phosphate-Dependent Fold Type IV Transaminases in Bacillus altitudinis W3 ». Catalysts 10, n^o 11 (12 novembre 2020) : 1308. http://dx.doi.org/10.3390/catal10111308.

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Aminotransferases are employed as industrial biocatalysts to produce chiral amines with high enantioselectivity and yield. BpTA-1 and BpTA-2 are the only two pyridoxal 5′-phosphate-dependent fold type IV transaminase enzymes in Bacillus altitudinis W3. Herein, we compared the structures and biochemical characteristics of BpTA-1 and BpTA-2 using bioinformatic analysis, circular dichroism spectroscopy, atomic force microscopy and other approaches. BpTA-1 and BpTA-2 are similar overall; both form homodimers and utilize a catalytic lysine. However, there are distinct differences in the substrate cofactor-binding pocket, molecular weight and the proportion of the secondary structure. Both enzymes have the same stereoselectivity but different enzymatic properties. BpTA-2 is more active under partial alkaline and ambient temperature conditions and BpTA-1 is more sensitive to pH and temperature. BpTA-2 as novel enzyme not only fills the building blocks of transaminase but also has broader industrial application potential for (R)-α-phenethylamines than BpTA-1. Structure-function relationships were explored to assess similarities and differences. The findings lay the foundation for modifying these enzymes via protein engineering to enhance their industrial application potential.

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Nair, Radhika R., Mothi Krishna Mohan et Sunaja Devi. « Enhanced Photocatalytic Activity of La3+ doped Bicrystalline Titania Prepared via Combustion method for the Degradation of Cationic dye Under Solar Illumination ». Bulletin of Chemical Reaction Engineering & ; Catalysis 13, n^o 1 (2 avril 2018) : 119. http://dx.doi.org/10.9767/bcrec.13.1.1427.119-126.

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La3+ doped TiO2 photocatalysts were successfully synthesized by combustion method in the presence of urea and were characterized by various physico-chemical techniques. Further, the photocatalytic performance of the synthesized catalysts was monitored by photocatalytic degradation of synthetic cationic dye-Methylene Blue (MB) under solar illumination. The bicrystalline phase of anatase and rutile was confirmed by X-ray diffraction analysis. Moreover, the transformation from anatase to rutile phase proceeds at a slower rate in the La3+ doped TiO2 catalysts. Effective separation of charge carriers, a synergistic effect in the bicrystalline framework of anatase and rutile, smaller crystallite size, and higher concentration of surface adsorbed hydroxyl groups helped these catalysts to show improved activity for the dye degradation. Copyright © 2018 BCREC Group. All rights reservedReceived: 28th July 2017; Revised: 19th October 2017; Accepted: 30th October 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018How to Cite: Nair, R.R., Mohan, M.K., Sunajadevi, K.R. (2018). Enhanced Photocatalytic Activity of La3+ doped Bicrystalline Titania Prepared via Combustion method for the Degradation of Cationic dye Under Solar Illumination. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (1): 119-126 (doi:10.9767/bcrec.13.1.1427.119-126)

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Navin, Chelliah V., Katla Sai Krishna, Chandra S. Theegala et Challa S. S. R. Kumar. « Lab-on-a-chip devices for gold nanoparticle synthesis and their role as a catalyst support for continuous flow catalysis ». Nanotechnology Reviews 3, n^o 1 (1 février 2014) : 39–63. http://dx.doi.org/10.1515/ntrev-2013-0028.

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AbstractLab-on-a-chip (LOC) systems are extensively used in recent times for applications in nanotechnology ranging from synthesis of nanomaterials to their utilization in catalysis, biomedicine, and drug delivery. A variety of nanomaterials – inorganic materials such as metal, metal oxide, quantum dots, and organic materials based on polymers and biological molecules – have been synthesized and their applications explored based on LOC devices. Among several inorganic nanomaterials, the applications of LOC devices for gold-based nanomaterials have been widely investigated over the past couple of decades. Though the synthesis and applications of inorganic nanomaterials using these systems have been thoroughly reviewed earlier, including those from our group, there are only a few recent review articles that cover gold-based nanomaterials. As the promise of supported gold nanoparticles (NPs) as exceptionally effective catalysts is beginning to be realized, LOC-based approach for continuous flow gold catalysis has begun to be exploited. Here, in this review, we focus on synthesis and catalysis applications of nanostructured gold using the LOC systems. With millifluidics-based LOCs gaining traction, this review fulfills the need for a comprehensive analysis covering both traditional microfluidics as well as recent millifluidics for catalysis applications utilizing gold nanomaterials.

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Xu, Xinzhou, Lu Zhang, Julie Tung Sem Chu, Yuqing Wang, Alex Wing Hong Chin, Tin Hang Chong, Zixi Dai, Leo Lit Man Poon, Peter Pak-Hang Cheung et Xuhui Huang. « A novel mechanism of enhanced transcription activity and fidelity for influenza A viral RNA-dependent RNA polymerase ». Nucleic Acids Research 49, n^o 15 (11 août 2021) : 8796–810. http://dx.doi.org/10.1093/nar/gkab660.

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Abstract During RNA elongation, the influenza A viral (IAV) RNA-dependent RNA polymerase (RdRp) residues in the active site interact with the triphosphate moiety of nucleoside triphosphate (NTP) for catalysis. The molecular mechanisms by which they control the rate and fidelity of NTP incorporation remain elusive. Here, we demonstrated through enzymology, virology and computational approaches that the R239 and K235 in the PB1 subunit of RdRp are critical to controlling the activity and fidelity of transcription. Contrary to common beliefs that high-fidelity RdRp variants exert a slower incorporation rate, we discovered a first-of-its-kind, single lysine-to-arginine mutation on K235 exhibited enhanced fidelity and activity compared with wild-type. In particular, we employed a single-turnover NTP incorporation assay for the first time on IAV RdRp to show that K235R mutant RdRp possessed a 1.9-fold increase in the transcription activity of the cognate NTP and a 4.6-fold increase in fidelity compared to wild-type. Our all-atom molecular dynamics simulations further elucidated that the higher activity is attributed to the shorter distance between K235R and the triphosphate moiety of NTP compared with wild-type. These results provide novel insights into NTP incorporation and fidelity control mechanisms, which lay the foundation for the rational design of IAV vaccine and antiviral targets.

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Bogomolova, T. S., M. Yu Smirnova et O. V. Klimov. « Catalysts and Know-how of Environmentally Friendly Low Pour Point Diesel Fuels ». Ecology and Industry of Russia 26, n^o 12 (30 novembre 2022) : 15–21. http://dx.doi.org/10.18412/1816-0395-2022-12-15-21.

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The Institute of Catalysis of the Siberian Branch of the Russian Academy of Sciences has developed high-performance catalysts for producing low pour point diesel fractions, which combine the main advantages of iso- and dewaxing processes. It has been confirmed that catalysts make it possible to obtain environmentally friendly diesel fuels while maintaining a high yield and quality of the target product.

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ZHANG, Hang, Na LI, Qulan ZHOU, Chen LV, Sijia HUANG et Jizhao SHEN. « ICOPE-15-C068 The selective catalytic reduction of NO_x with CH_4 on La_<1-x>Sr_xMnO_3 (x=0.2, 0.4) catalysts ». Proceedings of the International Conference on Power Engineering (ICOPE) 2015.12 (2015) : _ICOPE—15——_ICOPE—15—. http://dx.doi.org/10.1299/jsmeicope.2015.12._icope-15-_152.

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LASS, Achim, Jutta BELKNER, Hermann ESTERBAUER et Hartmut KÜHN. « Lipoxygenase treatment render low-density lipoprotein susceptible to Cu2+-catalysed oxidation ». Biochemical Journal 314, n^o 2 (1 mars 1996) : 577–85. http://dx.doi.org/10.1042/bj3140577.

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Oxidative modification of low-density lipoprotein (LDL) has been implicated in foam-cell formation at all stages of atherosclerosis. Since transition metals and mammalian 15-lipoxygenases are capable of oxidizing LDL to its atherogenic form, a concerted action of these two catalysts in atherogenesis has been suggested. Cu2+-catalysed LDL oxidation is characterized by a kinetic lag period in which the lipophilic antioxidants are decomposed and by a complex mixture of unspecific oxidation products. We investigated the kinetics of the 15-lipoxygenase-catalysed oxygenation of LDL and found that the enzyme is capable of oxidizing LDL in the presence of the endogenous lipophilic antioxidants. In contrast with the Cu2+-catalysed reaction, no kinetic lag phase was detected. The pattern of products formed during short-term incubations was highly specific, with cholesterol-esterified (13S)-hydroperoxy-(9Z,11E)-octadecadienoic acid being the major product. However, after long-term incubations the product pattern was less specific. Preincubation with 15-lipoxygenase rendered human LDL more susceptible to Cu2+-catalysed oxidation as indicated by a dramatic shortening of the lag period. Addition of Cu2+ to lipoxygenase-treated LDL led to a steep decline in its antioxidant content and to a greatly reduced lag period. Interestingly, if normalized to a comparable hydroperoxide content, autoxidation and addition of exogenous hydroperoxy fatty acids both failed to overcome the lag period. The local peroxide concentrations in various LDL subcompartments will be discussed as a possible reason for this unexpected behaviour.

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Gomes, Ruan, Denilson Costa, Roberto Junior, Milena Santos, Cristiane Rodella, Roger Fréty, Alessandra Beretta et Soraia Brandão. « Dry Reforming of Methane over NiLa-Based Catalysts : Influence of Synthesis Method and Ba Addition on Catalytic Properties and Stability ». Catalysts 9, n^o 4 (30 mars 2019) : 313. http://dx.doi.org/10.3390/catal9040313.

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CO2 reforming of CH4 to produce CO and H2 is a traditional challenge in catalysis. This area is still very active because of the potentials offered by the combined utilization of two green-house gases. The development of active, stable, and economical catalysts remains a key factor for the exploitation of natural gas (NG) with captured CO2 and biogas to produce chemicals or fuels via syngas. The major issue associated with the dry reforming process is catalyst deactivation by carbon deposition. The development of suitable catalyst formulations is one strategy for the mitigation of coking which becomes especially demanding when noble metal-free catalysts are targeted. In this work NiLa-based catalyst obtained from perovskite precursors La1−xBaxNiO3 (x = 0.0; 0.05; 0.1 and 0.2) and NiO/La2O3 were synthesized, characterized by in situ and operando XRD and tested in the dry reforming of methane. The characterization results showed that the addition of barium promoted BaCO3 segregation and changes in the catalyst structure. This partly affected the activity; however, the incorporation of Ba improved the catalyst resistance to deactivation process. The Ba-containing and Ba-free NiLa-based catalysts performed significantly better than NiO/La2O3 catalysts obtained by wet impregnation.

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Friščić, Tomislav, et Jean-Louis Do. « Chemistry 2.0 : Developing a New, Solvent-Free System of Chemical Synthesis Based on Mechanochemistry ». Synlett 28, n^o 16 (17 août 2017) : 2066–92. http://dx.doi.org/10.1055/s-0036-1590854.

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Mechanochemistry by grinding or milling has grown from a laboratory curiosity to a versatile approach for the synthesis and discovery of molecules, materials and reactivity. Focusing on organic synthesis and the chemistry of organic solids in general, we now provide a snapshot of this exciting, rapidly developing area, with the intention to illustrate its potential in establishing a more efficient and environmentally friendly system of chemical and materials synthesis, based on solid-state transformations rather than conventional, solution-dependent chemistry.1 What is Chemistry 2.0?2 Introduction2.1 Why Mechanochemistry Now?2.2 What’s in a Mechanochemistry Laboratory?3 Liquid-Assisted Grinding (LAG): Controlling Mechanochemistry4 The Solvent-Free Research Laboratory5 Medicinal Mechanochemistry6 Exploring Molecular Recognition7 Some Myths to Dispel8 Catalytic Reactions by Mechanochemistry8.1 Catalysis and Reactivity Involving Bulk Metals8.2 Enzyme Catalysis in Mechanochemistry8.3 Coupling of Mechanochemistry, Photochemistry and Supramolecular Catalysis9 Organometallic Mechanochemistry10 New Opportunities10.1 Stoichiometric Control10.2 ‘Impossible’ Molecules10.3 Reaction Discovery by Mechanochemistry11 Energetics of Mechanochemistry12 Mechanistic Understanding13 Real-Time Reaction Monitoring14 Conclusions

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Ali, Majid, Murat Bozdag, Umar Farooq, Andrea Angeli, Fabrizio Carta, Paola Berto, Giuseppe Zanotti et Claudiu T. Supuran. « Benzylaminoethyureido-Tailed Benzenesulfonamides : Design, Synthesis, Kinetic and X-ray Investigations on Human Carbonic Anhydrases ». International Journal of Molecular Sciences 21, n^o 7 (7 avril 2020) : 2560. http://dx.doi.org/10.3390/ijms21072560.

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A drug design strategy of carbonic anhydrase inhibitors (CAIs) belonging to sulfonamides incorporating ureidoethylaminobenzyl tails is presented. A variety of substitution patterns on the ring and the tails, located on para- or meta- positions with respect to the sulfonamide warheads were incorporated in the new compounds. Inhibition of human carbonic anhydrases (hCA) isoforms I, II, IX and XII, involving various pathologies, was assessed with the new compounds. Selective inhibitory profile towards hCA II was observed, the most active compounds being low nM inhibitors (KIs of 2.8–9.2 nM, respectively). Extensive X-ray crystallographic analysis of several sulfonamides in an adduct with hCA I allowed an in-depth understanding of their binding mode and to lay a detailed structure-activity relationship.

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Delamere, C., C. Jakins et E. Lewars. « On the generation of oxirene and dimethyloxirene by retro-DielsAlder reactions, and reactions of dimethyloxirene : a computational study ». Canadian Journal of Chemistry 80, n^o 1 (1 janvier 2002) : 94–105. http://dx.doi.org/10.1139/v01-194.

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The isomerization of oxirene (oxacyclopropene) (1) to ketene, dimethyloxirene (7) to dimethylketene via the oxo carbene ("ketocarbene"), and the retro-DielsAlder extrusion of oxirene and dimethyloxirene from their formal adducts (9 and 24, respectively) with benzene were studied computationally. All species were optimized at the MP2(fc)/631G(df,p) level; the species involving 1 were also subjected to MP2(fc)/631G(df,p) frequency and single-point CCSD(T)/631G(df,p) calculations. At the CCSD(T)/631G(df,p)//MP2(fc)/631G(df,p) level 1 isomerized to ketene in one step with a barrier of 2.8 kJ mol1 and a reaction energy of 320.6 kJ mol1. The extrusion of 1 from 9 had a late transition state and activation and reaction energies of 264.2 and 214.2 kJ mol1, respectively, cf. cyclopropene extrusion from its adduct (192.3 and 95.9 kJ mol1), indicating an antiaromatic destabilization energy of 214.2 95.9 = 118 kJ mol1 for 1. The carbene 8 from ring-opening of 7 lay 10.9 kJ mol1 above 7 (CCSD(T)/631G(df,p)//MP2(fc)/631G(df,p)), but the transition state could not be found; 8 isomerized to dimethylketene (252.7 kJ mol1 below 7) with a barrier of 16.4 kJ mol1, and to s-(Z)- and s-(E)-butenone with barriers of 28.5 and 35.4 kJ mol1, respectively. The UV (TDDFT, B3P86/6311++G**//MP2(fc)/631G(df,p)) spectra of 1 and 7 were calculated. Discrepancies were seen between the calculated IR spectra of 7 (bis(trifluoromethyl)oxirene) and perfluoro ethyl methyloxirene, and those attributed to these species in earlier matrix-isolation work. Key words: oxirene, dimethyloxirene, ab initio, retro-DielsAlder, DielsAlder.

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Mari, Matteo, Debora Carrozza, Erika Ferrari et Mattia Asti. « Applications of Radiolabelled Curcumin and Its Derivatives in Medicinal Chemistry ». International Journal of Molecular Sciences 22, n^o 14 (10 juillet 2021) : 7410. http://dx.doi.org/10.3390/ijms22147410.

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Curcumin is a natural occurring molecule that has aroused much interest among researchers over the years due to its pleiotropic set of biological properties. In the nuclear medicine field, radiolabelled curcumin and curcumin derivatives have been studied as potential radiotracers for the early diagnosis of Alzheimer’s disease and cancer. In the present review, the synthetic pathways, labelling methods and the preclinical investigations involving these radioactive compounds are treated. The studies entailed chemical modifications for enhancing curcumin stability, as well as its functionalisation for the labelling with several radiohalogens or metal radionuclides (fluorine-18, technetium-99m, gallium-68, etc.). Although some drawbacks have yet to be addressed, and none of the radiolabelled curcuminoids have so far achieved clinical application, the studies performed hitherto provide useful insights and lay the foundation for further developments.

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Su, Jingqian, Fen Zhou, Shun Wu et Zhiyong Tong. « Research Progress on Natural Small-Molecule Compounds for the Prevention and Treatment of Sepsis ». International Journal of Molecular Sciences 24, n^o 16 (12 août 2023) : 12732. http://dx.doi.org/10.3390/ijms241612732.

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Sepsis is a serious disease with high mortality and has been a hot research topic in medical research in recent years. With the continuous reporting of in-depth research on the pathological mechanisms of sepsis, various compounds have been developed to prevent and treat sepsis. Natural small-molecule compounds play vital roles in the prevention and treatment of sepsis; for example, compounds such as resveratrol, emodin, salidroside, ginsenoside, and others can modulate signaling through the NF-κB, STAT3, STAT1, PI3K, and other pathways to relieve the inflammatory response, immunosuppression, and organ failure caused by sepsis. Here, we discuss the functions and mechanisms of natural small-molecule compounds in preventing and treating sepsis. This review will lay the theoretical foundation for discovering new natural small-molecule compounds that can potentially prevent and treat sepsis.

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Drozdov, Anatoliy, Egor Lebedev et Leonid Adonin. « Comparative Analysis of Bivalve and Sea Urchin Genetics and Development : Investigating the Dichotomy in Bilateria ». International Journal of Molecular Sciences 24, n^o 24 (5 décembre 2023) : 17163. http://dx.doi.org/10.3390/ijms242417163.

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This comprehensive review presents a comparative analysis of early embryogenesis in Protostomia and Deuterostomia, the first of which exhibit a mosaic pattern of development, where cells are fated deterministically, while Deuterostomia display a regulatory pattern of development, where the fate of cells is indeterminate. Despite these fundamental differences, there are common transcriptional mechanisms that underline their evolutionary linkages, particularly in the field of functional genomics. By elucidating both conserved and unique regulatory strategies, this review provides essential insights into the comparative embryology and developmental dynamics of these groups. The objective of this review is to clarify the shared and distinctive characteristics of transcriptional regulatory mechanisms. This will contribute to the extensive areas of functional genomics, evolutionary biology and developmental biology, and possibly lay the foundation for future research and discussion on this seminal topic.

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Jin, Run, Aidan Kai Yeung Chan, Jingsong Wu et Tatia Mei Chun Lee. « Relationships between Inflammation and Age-Related Neurocognitive Changes ». International Journal of Molecular Sciences 23, n^o 20 (20 octobre 2022) : 12573. http://dx.doi.org/10.3390/ijms232012573.

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The relationship between inflammation and age-related neurocognitive changes is significant, which may relate to the age-related immune dysfunctions characterized by the senescence of immune cells and elevated inflammatory markers in the peripheral circulation and the central nervous system. In this review, we discuss the potential mechanisms, including the development of vascular inflammation, neuroinflammation, organelle dysfunctions, abnormal cholesterol metabolism, and glymphatic dysfunctions as well as the role that the key molecules play in the immune-cognition interplay. We propose potential therapeutic pharmacological and behavioral strategies for ameliorating age-related neurocognitive changes associated with inflammation. Further research to decipher the multidimensional roles of chronic inflammation in normal and pathological aging processes will help unfold the pathophysiological mechanisms underpinning neurocognitive disorders. The insight gained will lay the path for developing cost-effective preventative measures and the buffering or delaying of age-related neurocognitive decline.

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Skinkis, Patricia A., et Katherine R. McLaughlin. « Pinot noir Crop Estimation Method Allows Growers to Estimate Yields Earlier than Lag Phase ». Catalyst : Discovery into Practice 6, n^o 1 (17 décembre 2021) : 30–37. http://dx.doi.org/10.5344/catalyst.2021.21005.

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Dai, Liping, Peiyuan Li, Qing Li, Yujia Leng, Dali Zeng et Qian Qian. « Integrated Multi-Omics Perspective to Strengthen the Understanding of Salt Tolerance in Rice ». International Journal of Molecular Sciences 23, n^o 9 (7 mai 2022) : 5236. http://dx.doi.org/10.3390/ijms23095236.

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Salt stress is one of the major constraints to rice cultivation worldwide. Thus, the development of salt-tolerant rice cultivars becomes a hotspot of current rice breeding. Achieving this goal depends in part on understanding how rice responds to salt stress and uncovering the molecular mechanism underlying this trait. Over the past decade, great efforts have been made to understand the mechanism of salt tolerance in rice through genomics, transcriptomics, proteomics, metabolomics, and epigenetics. However, there are few reviews on this aspect. Therefore, we review the research progress of omics related to salt tolerance in rice and discuss how these advances will promote the innovations of salt-tolerant rice breeding. In the future, we expect that the integration of multi-omics salt tolerance data can accelerate the solution of the response mechanism of rice to salt stress, and lay a molecular foundation for precise breeding of salt tolerance.

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Yang, Jing-Fang, Le-Rong Shi, Ke-Chen Wang, Li-Long Huang, Yun-Shuang Deng, Mo-Xian Chen, Fang-Hao Wan et Zhong-Shi Zhou. « HDAC1 : An Essential and Conserved Member of the Diverse Zn2+-Dependent HDAC Family Driven by Divergent Selection Pressure ». International Journal of Molecular Sciences 24, n^o 23 (2 décembre 2023) : 17072. http://dx.doi.org/10.3390/ijms242317072.

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Zn2+-dependent histone deacetylases (HDACs) are enzymes that regulate gene expression by removing acetyl groups from histone proteins. These enzymes are essential in all living systems, playing key roles in cancer treatment and as potential pesticide targets. Previous phylogenetic analyses of HDAC in certain species have been published. However, their classification and evolutionary origins across biological kingdoms remain unclear, which limits our understanding of them. In this study, we collected the HDAC sequences from 1451 organisms and performed analyses. The HDACs are found to diverge into three classes and seven subclasses under divergent selection pressure. Most subclasses show species specificity, indicating that HDACs have evolved with high plasticity and diversification to adapt to different environmental conditions in different species. In contrast, HDAC1 and HDAC3, belonging to the oldest class, are conserved and crucial in major kingdoms of life, especially HDAC1. These findings lay the groundwork for the future application of HDACs.

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Cheng, Jie, Shujian Xiao, Qing Luo, Bangxu Wang, Rumei Zeng, Liming Zhao et Jiamin Zhang. « Engineering an Artificial Pathway to Improve the Bioconversion of Lysine into Chiral Amino Alcohol 2-Hydroxycadaverine Using a Semi-Rational Design ». Fermentation 10, n^o 1 (13 janvier 2024) : 56. http://dx.doi.org/10.3390/fermentation10010056.

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Amino alcohols are important compounds that are widely used in the polymer and pharmaceutical industry, particularly when used as chiral scaffolds in organic synthesis. The hydroxylation of polyamide polymers may allow crosslinking between molecular chains through the esterification reactions of hydroxyl and carboxyl groups. Therefore, this may alter the functional properties of polyamide polymers. 2-hydroxycadaverine (2HyC), as a new type of chiral amino alcohol, has potential applications in the pharmaceutical, chemical, and polymer industries. Currently, 2HyC production has only been realized via pure enzyme catalysis or two-stage whole-cell biocatalysis, which faces great challenges for scale-up production. However, the use of a cell factory is very promising for the production of 2HyC in industrial applications. Here, we designed and constructed a promising artificial pathway in Escherichia coli for producing 2HyC from biomass-derived lysine. This biosynthesis route expands the lysine catabolism pathway and employs two enzymes to sequentially convert lysine into 2HyC. However, the catalytic activity of wild-type pyridoxal phosphate-dependent decarboxylase from Chitinophage pinensis (DCCp) toward 3-hydroxylysine is lower, resulting in the lower production of 2HyC. Thus, the higher catalytic activity of DCCp is desired for low-cost and expanded industrial applications of 2HyC. To improve the catalytic activity of DCCp, a mutant library of DCCp was first built using a semi-rational design. The Kcat/Km of mutant DCCp (R53D/V94I) increased by 63%. A titer of 359 mg/L 2HyC was produced in shake flasks, with a 2HyC titer increase of 54% compared to control strain ML101. The results show that the production of 2HyC was effectively increased through a semi-rational design strategy. These findings lay the foundation for the development and utilization of renewable resources to produce 2HyC in microorganisms via an efficient, green, and sustainable biosynthetic strategy for further industrial application.

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PAGANI, Franco, Rajalakshmi PARIYARATH, Cristiana STUANI, Rodolfo GARCIA et Francisco E. BARALLE. « Cysteine residues in human lysosomal acid lipase are involved in selective cholesteryl esterase activity ». Biochemical Journal 326, n^o 1 (15 août 1997) : 265–69. http://dx.doi.org/10.1042/bj3260265.

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Human lysosomal acid lipase (LAL) catalyses the deacylation of triacylglycerol and cholesteryl esters in the acidic lysosomal compartment. Treatment of LAL with the reducing agent dithiothreitol affected the triacylglycerol and cholesteryl esterase activities differentially, suggesting the involvement of cysteine residues in determining substrate specificity. To identify the residues involved, human LAL cDNA, under the control of the T7 promoter and tagged with a herpes simplex virus coding epitope, was specifically mutated in order to introduce single amino acid substitutions of each of the six cysteine residues of mature LAL. All Cys-227 mutants showed selectively decreased activity towards cholesteryl oleate, while preserving that towards trioleylglycerol. Substitutions of Cys-236, Cys-240 and Cys-244 affected catalysis towards the two substrates to a variable degree, depending on the side chain of the amino acid introduced. The replacement of Cys-41 or Cys-188 did not result in the preferential cleavage of either one of the two substrates. These data indicate that Cys-227, Cys-236, Cys-240 and Cys-244 play a crucial role in determining LAL substrate specificity. We propose that these cysteine residues are involved in the hydrolysis of cholesteryl ester by affecting selectively the access of this substrate to the catalytic active site. In addition, the fact that the catalytic activity is never completely abolished in cysteine mutants demonstrates that LAL is not a thiol enzyme.

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Zhao, Conghui, Zhenming Yu, Jaime A. Teixeira da Silva, Chunmei He, Haobin Wang, Can Si, Mingze Zhang, Danqi Zeng et Jun Duan. « Functional Characterization of a Dendrobium officinale Geraniol Synthase DoGES1 Involved in Floral Scent Formation ». International Journal of Molecular Sciences 21, n^o 19 (23 septembre 2020) : 7005. http://dx.doi.org/10.3390/ijms21197005.

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Floral scent is a key ornamental trait that determines the quality and commercial value of orchids. Geraniol, an important volatile monoterpene in orchids that attracts pollinators, is also involved in responses to stresses but the geraniol synthase (GES) responsible for its synthesis in the medicinal orchid Dendrobium officinale has not yet been identified. In this study, three potential geraniol synthases were mined from the D. officinale genome. DoGES1, which was localized in chloroplasts, was characterized as a geraniol synthase. DoGES1 was highly expressed in flowers, especially in petals. DoGES1 transcript levels were high in the budding stage of D. officinale flowers at 11:00 a.m. DoGES1 catalyzed geraniol in vitro, and transient expression of DoGES1 in Nicotiana benthamiana leaves resulted in the accumulation of geraniol in vivo. These findings on DoGES1 advance our understanding of geraniol biosynthesis in orchids, and lay the basis for genetic modification of floral scent in D. officinale or in other ornamental orchids.

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Song, Yun, Li Feng, Mohammed Abdul Muhsen Alyafei, Abdul Jaleel et Maozhi Ren. « Function of Chloroplasts in Plant Stress Responses ». International Journal of Molecular Sciences 22, n^o 24 (15 décembre 2021) : 13464. http://dx.doi.org/10.3390/ijms222413464.

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The chloroplast has a central position in oxygenic photosynthesis and primary metabolism. In addition to these functions, the chloroplast has recently emerged as a pivotal regulator of plant responses to abiotic and biotic stress conditions. Chloroplasts have their own independent genomes and gene-expression machinery and synthesize phytohormones and a diverse range of secondary metabolites, a significant portion of which contribute the plant response to adverse conditions. Furthermore, chloroplasts communicate with the nucleus through retrograde signaling, for instance, reactive oxygen signaling. All of the above facilitate the chloroplast’s exquisite flexibility in responding to environmental stresses. In this review, we summarize recent findings on the involvement of chloroplasts in plant regulatory responses to various abiotic and biotic stresses including heat, chilling, salinity, drought, high light environmental stress conditions, and pathogen invasions. This review will enrich the better understanding of interactions between chloroplast and environmental stresses, and will lay the foundation for genetically enhancing plant-stress acclimatization.

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Hou, Qiandong, Zhilang Qiu, Zhuang Wen, Huimin Zhang, Zhengchun Li, Yi Hong, Guang Qiao et Xiaopeng Wen. « Genome-Wide Identification of ARF Gene Family Suggests a Functional Expression Pattern during Fruitlet Abscission in Prunus avium L. » International Journal of Molecular Sciences 22, n^o 21 (4 novembre 2021) : 11968. http://dx.doi.org/10.3390/ijms222111968.

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Auxin response factors (ARFs) play a vital role in plant growth and development. In the current study, 16 ARF members have been identified in the sweet cherry (Prunus avium L.) genome. These genes are all located in the nucleus. Sequence analysis showed that genes in the same subgroup have similar exon-intron structures. A phylogenetic tree has been divided into five groups. The promoter sequence includes six kinds of plant hormone-related elements, as well as abiotic stress response elements such as low temperature or drought. The expression patterns of PavARF in different tissues, fruitlet abscission, cold and drought treatment were comprehensively analyzed. PavARF10/13 was up-regulated and PavARF4/7/11/12/15 was down-regulated in fruitlet abscising. These genes may be involved in the regulation of fruit drop in sweet cherry fruits. This study comprehensively analyzed the bioinformatics and expression pattern of PavARF, which can lay the foundation for further understanding the PavARF family in plant growth development and fruit abscission.

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Gao, Jie, Yue Hao, Xiangshu Piao et Xianhong Gu. « Aldehyde Dehydrogenase 2 as a Therapeutic Target in Oxidative Stress-Related Diseases : Post-Translational Modifications Deserve More Attention ». International Journal of Molecular Sciences 23, n^o 5 (28 février 2022) : 2682. http://dx.doi.org/10.3390/ijms23052682.

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Aldehyde dehydrogenase 2 (ALDH2) has both dehydrogenase and esterase activity; its dehydrogenase activity is closely related to the metabolism of aldehydes produced under oxidative stress (OS). In this review, we recapitulate the enzyme activity of ALDH2 in combination with its protein structure, summarize and show the main mechanisms of ALDH2 participating in metabolism of aldehydes in vivo as comprehensively as possible; we also integrate the key regulatory mechanisms of ALDH2 participating in a variety of physiological and pathological processes related to OS, including tissue and organ fibrosis, apoptosis, aging, and nerve injury-related diseases. On this basis, the regulatory effects and application prospects of activators, inhibitors, and protein post-translational modifications (PTMs, such as phosphorylation, acetylation, S-nitrosylation, nitration, ubiquitination, and glycosylation) on ALDH2 are discussed and prospected. Herein, we aimed to lay a foundation for further research into the mechanism of ALDH2 in oxidative stress-related disease and provide a basis for better use of the ALDH2 function in research and the clinic.

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de Silva, Tharushi Ayanthika, Simon Apte, Joanne Voisey, Kirsten Spann, Maxine Tan, Chandima Divithotawela, Daniel Chambers et Brendan O’Sullivan. « Single-Cell Profiling of Cells in the Lung of a Patient with Chronic Hypersensitivity Pneumonitis Reveals Inflammatory Niche with Abundant CD39+ T Cells with Functional ATPase Phenotype : A Case Study ». International Journal of Molecular Sciences 24, n^o 19 (22 septembre 2023) : 14442. http://dx.doi.org/10.3390/ijms241914442.

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This study investigated immune cell characteristics in chronic hypersensitivity pneumonitis (HP), focusing on CD39-expressing cells’ impact on inflammation and tissue remodelling. Lung tissue from an HP patient was analysed using single-cell transcriptomics, flow cytometry, and gene expression profiling. The tissue revealed diverse cell types like macrophages, T cells, fibroblasts, and regulatory T cells (Tregs). CD39-expressing Tregs exhibited heightened ATP hydrolysis capacity and regulatory gene expression. CD39hi cells displayed markers of both Tregs and proinflammatory Th17 cells, suggesting transitional properties. Communication networks involving molecules like SPP1, collagen, CSF1, and IL-1β were identified, hinting at interactions between cell types in HP pathogenesis. This research provides insights into the immune response and cell interactions in chronic HP. CD39-expressing cells dual nature as Tregs and Th17 cells suggests a role in modulating lung inflammation, potentially affecting disease progression. These findings lay the groundwork for further research, underscoring CD39-expressing cells as potential therapeutic targets in HP.

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Sotomayor-Lugo, Francisco, Nataly Iglesias-Barrameda, Yandy Castillo-Aleman, Imilla Casado-Hernandez, Carlos Villegas-Valverde, Antonio Bencomo-Hernandez, Yendry Ventura-Carmenate et Rene Rivero-Jimenez. « The Dynamics of Histone Modifications during Mammalian Zygotic Genome Activation ». International Journal of Molecular Sciences 25, n^o 3 (25 janvier 2024) : 1459. http://dx.doi.org/10.3390/ijms25031459.

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Mammalian fertilization initiates the reprogramming of oocytes and sperm, forming a totipotent zygote. During this intricate process, the zygotic genome undergoes a maternal-to-zygotic transition (MZT) and subsequent zygotic genome activation (ZGA), marking the initiation of transcriptional control and gene expression post-fertilization. Histone modifications are pivotal in shaping cellular identity and gene expression in many mammals. Recent advances in chromatin analysis have enabled detailed explorations of histone modifications during ZGA. This review delves into conserved and unique regulatory strategies, providing essential insights into the dynamic changes in histone modifications and their variants during ZGA in mammals. The objective is to explore recent advancements in leading mechanisms related to histone modifications governing this embryonic development phase in depth. These considerations will be useful for informing future therapeutic approaches that target epigenetic regulation in diverse biological contexts. It will also contribute to the extensive areas of evolutionary and developmental biology and possibly lay the foundation for future research and discussion on this seminal topic.

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Wang, Dengbao, Zimo Qiu, Tao Xu, Sheng Yao, Mengyang Zhang, Xiang Cheng, Yulu Zhao et Kongshu Ji. « Identification and Expression Patterns of WOX Transcription Factors under Abiotic Stresses in Pinus massoniana ». International Journal of Molecular Sciences 25, n^o 3 (28 janvier 2024) : 1627. http://dx.doi.org/10.3390/ijms25031627.

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WUSCHEL-related homeobox (WOX) transcription factors (TFs) play a crucial role in regulating plant development and responding to various abiotic stresses. However, the members and functions of WOX proteins in Pinus massoniana remain unclear. In this study, a total of 11 WOX genes were identified, and bioinformatics methods were used for preliminary identification and analysis. The phylogenetic tree revealed that most PmWOXs were distributed in ancient and WUS clades, with only one member found in the intermediate clade. We selected four highly conserved WOX genes within plants for further expression analysis. These genes exhibited expressions across almost all tissues, while PmWOX2, PmWOX3, and PmWOX4 showed high expression levels in the callus, suggesting their potential involvement in specific functions during callus development. Expression patterns under different abiotic stresses indicated that PmWOXs could participate in resisting multiple stresses in P. massoniana. The identification and preliminary analysis of PmWOXs lay the foundation for further research on analyzing the resistance molecular mechanism of P. massoniana to abiotic stresses.

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Lan, Zhong, Xin Li et Xiaoqin Zhang. « Glioblastoma : An Update in Pathology, Molecular Mechanisms and Biomarkers ». International Journal of Molecular Sciences 25, n^o 5 (6 mars 2024) : 3040. http://dx.doi.org/10.3390/ijms25053040.

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Glioblastoma multiforme (GBM) is the most common and malignant type of primary brain tumor in adults. Despite important advances in understanding the molecular pathogenesis and biology of this tumor in the past decade, the prognosis for GBM patients remains poor. GBM is characterized by aggressive biological behavior and high degrees of inter-tumor and intra-tumor heterogeneity. Increased understanding of the molecular and cellular heterogeneity of GBM may not only help more accurately define specific subgroups for precise diagnosis but also lay the groundwork for the successful implementation of targeted therapy. Herein, we systematically review the key achievements in the understanding of GBM molecular pathogenesis, mechanisms, and biomarkers in the past decade. We discuss the advances in the molecular pathology of GBM, including genetics, epigenetics, transcriptomics, and signaling pathways. We also review the molecular biomarkers that have potential clinical roles. Finally, new strategies, current challenges, and future directions for discovering new biomarkers and therapeutic targets for GBM will be discussed.

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Billing, David. « In situ PXRD studies of heterogeneous catalysts and pre-catalysts ». Acta Crystallographica Section A Foundations and Advances 70, a1 (5 août 2014) : C1178. http://dx.doi.org/10.1107/s2053273314088214.

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During the course of the last couple of years, my collaborators and I have studied a number of catalytic systems using a lab based PXRD facility at our disposal. Of particular interest to us has been the supported catalysts used in Fischer Tropsch catalysis as well as those used in the synthesis of multiwalled carbon nano tubes. These studies have all proven invaluable to the understanding of the often complex phase evolution that is an intricate and inherent part of the heterogeneous processes of interest to us. Selected results will be presented to illustrate the usefulness and value of these studies. For example below is the intensity profile of the diffraction patterns collected during the heat-treatment of the pre-catalyst: A – anatase, R – rutile, S – silicon, H – hematite and P – pseudobrookite

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Lin, Shuang, Shaohua Zeng, Biao A, Xiaoman Yang, Tianshun Yang, Guoqi Zheng, Guilian Mao et Ying Wang. « Integrative Analysis of Transcriptome and Metabolome Reveals Salt Stress Orchestrating the Accumulation of Specialized Metabolites in Lycium barbarum L. Fruit ». International Journal of Molecular Sciences 22, n^o 9 (23 avril 2021) : 4414. http://dx.doi.org/10.3390/ijms22094414.

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Salt stress seriously affects yield and quality of crops. The fruit of Lycium barbarum (LBF) is extensively used as functional food due to its rich nutrient components. It remains unclear how salt stress influences the quality of LBF. In this study, we identified 71 differentially accumulated metabolites (DAMs) and 1396 differentially expressed genes (DEGs) among ripe LBF with and without 300 mM of NaCl treatment. Pearson correlation analysis indicated that the metabolomic changes caused by salt stress were strongly related to oxidoreductases; hydrolases; and modifying enzymes, in particular, acyltransferases, methyltransferases and glycosyltransferases. Further analysis revealed that salt stress facilitated flavonoid glycosylation and carotenoid esterification by boosting the expression of structural genes in the biosynthetic pathways. These results suggested that salt stress prompts the modification of flavonoids and carotenoids to alleviate ROS damage, which in turn improves the quality of LBF. Our results lay a solid foundation for uncovering the underlying molecular mechanism of salt stress orchestrating LBF quality, and the candidate genes identified will be a valuable gene resource for genetic improvement of L. barbarum.

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Wu, Wenting, Peng Wang, Xiaochun Huang, Liwen Su, Haixuan Lv, Jiquan Gou, Zhikui Cheng, Lianlian Ma, Wenjin Yu et Zhengguo Liu. « Fine Mapping and Functional Analysis of Major Regulatory Genes of Soluble Solids Content in Wax Gourd (Benincasa hispida) ». International Journal of Molecular Sciences 23, n^o 13 (23 juin 2022) : 6999. http://dx.doi.org/10.3390/ijms23136999.

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Soluble solids content (SSC) is an important quality trait of wax gourd, but reports about its regulatory genes are scarce. In this study, the SSC regulatory gene BhSSC2.1 in wax gourd was mined via quantitative trait locus (QTL) mapping based on high-density genetic mapping containing 12 linkage groups (LG) and bulked segregant analysis (BSA)-seq. QTL mapping and BSA-seq revealed for the first time that the SSC QTL (107.658–108.176 cM) of wax gourd was on Chr2 (LG2). The interpretable phenotypic variation rate and maximum LOD were 16.033% and 6.454, respectively. The QTL interval contained 13 genes. Real-time fluorescence quantitative expression analysis, functional annotation, and sequence analysis suggested that Bch02G016960, named BhSSC2.1, was a candidate regulatory gene of the SSC in wax gourd. Functional annotation of this gene showed that it codes for a NADP-dependent malic enzyme. According to BhSSC2.1 sequence variation, an InDel marker was developed for molecular marker-assisted breeding of wax gourd. This study will lay the foundation for future studies regarding breeding and understanding genetic mechanisms of wax gourd.

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Nuzzi, Raffaele, et Paolo Caselgrandi. « Sex Hormones and Their Effects on Ocular Disorders and Pathophysiology : Current Aspects and Our Experience ». International Journal of Molecular Sciences 23, n^o 6 (17 mars 2022) : 3269. http://dx.doi.org/10.3390/ijms23063269.

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Sex hormones are molecules produced by the gonads and to a small extent by the adrenal gland, which not only determine the primary and secondary sexual characteristics of an individual, differentiating man from woman, but also participate in the functioning of the various systems of the body. The evidence that many eye diseases differ in terms of prevalence between men and women has allowed us, in recent years, to carry out several studies that have investigated the association between sex hormones and the pathophysiology of eye tissues. Specific receptors for sex hormones have been found on the lacrimal and meibomian glands, conjunctiva, cornea, lens, retina, and choroid. This work summarizes the current knowledge on the role that sex hormones play in the pathogenesis of the most common ocular disorders and indicates our clinical experience in these situations. The aim is to stimulate an interdisciplinary approach between endocrinology, neurology, molecular biology, and ophthalmology to improve the management of these diseases and to lay the foundations for new therapeutic strategies.

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