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The reaction electronic flux in chemical reactions

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Science China Chemistry 2011年第12期54卷 1982-1988页

作者： CERON María Luisa ECHEGARAY Eleonora GUTIRREZ-OLIVA Soledad HERRERA Barbara TORO-LABB Alejandro laboratorio de química Teorica Computacional(QTC) Facultad de química Pontificia Universidad Catolica de Chile

The mechanism of a chemical reaction can be characterized in terms of chemical events that take place during the *** events are bond weakening/breaking and/or bond strengthening/*** reaction electronic flux(REF),a concept that identifies and rationalizes the electronic activity taking place along the reaction coordinate,has emerged recently as a powerful tool for characterizing the mechanism of chemical reactions.A quantitative theory introducing new descriptors for characterizing reaction mechanisms is presented in detail and three illustrative examples are *** nucleophilic substitution reactions the REF indicates that bond breaking or forming events may be leading the electronic activity whereas in the methanol decomposition reaction by copper oxide,the REF allows to discover that consecutive electronic reductions of copper together with bond breaking processes control the course of the reaction.

关键词： reaction mechanisms chemical potential conceptual DFT reaction electronic flux (REF)

The best of both worlds:mastering nerve regeneration combining biological and nanotechnological tools

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Neural Regeneration Research 2023年第3期18卷 556-557页

作者： Paula A.Soto Marcela B.Fernández van Raap C.Patricia Setton-Avruj departamento de química Biológica Cátedra de Química Biológica PatológicaUniversidad de Buenos AiresFacultad de Farmacia y BioquímicaInstituto de Química y Fisicoquímica Biológicas(IQUIFIB)Universidad de Buenos AiresBuenos AiresArgentina departamento de Física Universidad Nacional de La Plata(UNLP)Facultad de Ciencias ExactasLa PlataArgentinaLaboratorio de BiotecnologíaUniversidad ORT UruguayMontevideoUruguay

Over the last decade,remarkable developments in nanotechnology have powered medical research,unveiling new approaches for the solution of public health issues such as the treatment of traumatic peripheral neuropathies.

关键词： traumatic technological treatment

Electrochemical reduction of Cr(Ⅵ)in the presence of sodium alginate and its application in water purification

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Journal of Environmental Sciences 2021年第3期33卷 304-312页

作者： Bryan Butter Paola Santander Guadalupe del CPizarro Diego POyarzún Federico Tasca Julio Sánchez Facultad de química y Biología Universidad de Santiago de ChileUSACHCasilla 40Correo 33SantiagoChile departamento de química Universidad Tecnológica MetropolitanaJ.P.Alessandri 1242SantiagoChile laboratorio de Nanotecnología Recursos Naturales y Sistemas ComplejosFacultad de Ciencias NaturalesUniversidad de AtacamaCopayapu 485CopiapóChile

Chromium(Cr)is used in many manufacturing processes,and its release into natural waters is a major environmental problem *** concentrations of Cr(Ⅵ)are toxic to human health and living organisms due to the carcinogenic and mutagenic nature of this *** work examined the conversion of Cr(Ⅵ)to Cr(Ⅲ)via electrochemical reduction using gold electrode in an acidic sodium alginate(SA)solution and subsequent removal of the produced Cr(Ⅲ)-SA by the polymer-enhanced ultrafiltration(PEUF)technique.A solution of SA in nitric acid was used both as an electrolytic medium during the voltammetric measurements and bulk electrolysis and as an extracting agent during the PEUF *** electroanalysis of Cr(Ⅵ)was performed by linear sweep voltammetry in the presence of acidic SA solution to study its voltammetric behavior as a function of the Cr(Ⅵ)concentration,pH,presence of Cr(Ⅲ),SA concentration and scan *** addition,the quantitative reduction of Cr(Ⅵ)to Cr(Ⅲ)was studied through the bulk electrolysis *** results showed efficient reduction with well-defined peaks at approximately 0.3 V ***/AgCl,using a gold working *** the pH increased,the reduction signal strongly decreased until its *** optimum SA concentration was 10 mmol/L,and it was observed that the presence of Cr(Ⅲ)did not interfere in the Cr(Ⅵ)*** the quantitative reduction by bulk electrolysis in the presence of acidic SA solution,it was possible to reduce all Cr(Ⅵ)to Cr(Ⅲ)followed by its removal via PEUF.

关键词： Alginate solution Chromium Electroanalytical chemistry Ultrafiltration Water purification

Bioactive peptides: A review

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Food quality and Safety 2017年第1期1卷 29-46页

作者： Adrián Sánchez Alfredo Vázquez laboratorio de Investigación en Inmunoquímica Dr.Márquez 162CuauhtémocDoctores06720CDMX departamento de química Orgánica Facultad de QuímicaUniversidad Nacional Autónoma de MéxicoMéxico

Bioactive peptides(BP)are organic substances formed by amino acids joined by covalent bonds known as amide or peptide *** some BP exist free in its natural source,the vast majority of known BP are encrypted in the structure of the parent proteins and are released mainly by enzymatic *** BP have been prepared by chemical *** play a significant role in human health by affecting the digestive,endocrine,cardiovascular,immune,and nervous *** are considered the new generation of biologically active regulators;they can prevent oxidation and microbial degradation in foods and also improve the treatment of various diseases and disorders,thus increasing the quality of *** growing interest in BP has incentivized the scientific community and the food industry to exploring the development of new food additives and functional products based on these *** present review highlights the recent findings on the identification,bioassays,and use of BP,as well as their potential use as food additives and in the development of functional products.

关键词： peptides bioactivity marine origin nutraceutical hydrolysis fermentation

Blockade of Rho-associated kinase prevents inhibition of axon regeneration of peripheral nerves induced by anti-ganglioside antibodies

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Neural Regeneration Research 2024年第4期19卷 895-899页

作者： Andrés Berardo Cristian R.Bacaglio Bárbara B.Báez Rubén Sambuelli Kazim A.Sheikh Pablo H.H.Lopez laboratorio de Neurobiología Instituto de Investigación Médica Mercedes y Martin Ferreyra(INIMEC)-Consejo Nacional de Investigaciones Cientificas y Técnicas(CONICET)Universidad Nacional de Córdoba departamento de química Biológica-Centro de Investigaciones en química Biológica de Córdoba(CIquIBIC)-Consejo Nacional de Investigaciones Cientificas y Técnicas(CONICET) Facultad de Cs.QuímicasUniversidad Nacional de Córdoba Servicio de Anatomía Patológica Clínica Universitaria Reina FabiolaUniversidad Católica de Córdoba department of Neurology University of Texas Medical School at Houston

Anti-ganglioside antibodies are associated with delayed/poor clinical recovery in Guillain-Barrèsyndrome,mostly related to halted axon ***-linking of cell surface gangliosides by anti-ganglioside antibodies triggers inhibition of nerve repair in in vitro and in vivo paradigms of axon *** effects involve the activation of the small GTPase Rho A/ROCK signaling pathways,which negatively modulate growth cone cytoskeleton,similarly to well stablished inhibitors of axon regeneration described so *** aim of this work was to perform a proof of concept study to demonstrate the effectiveness of Y-27632,a selective pharmacological inhibitor of ROCK,in a mouse model of axon regeneration of peripheral nerves,where the passive immunization with a monoclonal antibody targeting gangliosides GD1a and GT1b was previously reported to exert a potent inhibitory effect on regeneration of both myelinated and unmyelinated *** results demonstrate a differential sensitivity of myelinated and unmyelinated axons to the pro-regenerative effect of *** with a total dosage of 9 mg/kg of Y-27632 resulted in a complete prevention of anti-GD1a/GT1b monoclonal antibody-mediated inhibition of axon regeneration of unmyelinated fibers to skin and the functional recovery of mechanical cutaneous *** contrast,the same dose showed toxic effects on the regeneration of myelinated ***,scale down of the dosage of Y-27632 to 5 mg/kg resulted in a significant although not complete recovery of regenerated myelinated axons exposed to anti-GD1a/GT1b monoclonal antibody in the absence of toxicity in animals exposed to only ***,these findings confirm the in vivo participation of Rho A/ROCK signaling pathways in the molecular mechanisms associated with the inhibition of axon regeneration induced by anti-GD1a/GT1b monoclonal *** findings open the possibility of therapeutic pharmacological intervention targeting Rho A/R

关键词： anti-ganglioside antibodies anti-glycan antibodies axon regeneration ganglioside Guillain-Barrésyndrome nerve repair ROCK Y-27632

Biorefinery of Rice Husk to Obtain Functionalized Bioactive Compounds

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Journal of Renewable Materials 2019年第4期7卷 313-324页

作者： M.Lopretti N.Lecot A.Rodriguez G.Lluberas F.Orozco L.Bolaños G.Montes de Oca H.Cerecetto J.Vega-Baudrit laboratorio de Técnicas Nucleares Aplicadas a Bioquímica y Biotecnología Centro de Investigaciones Nucleares-Facultad de CienciasMataojo 2055Montevideo CP 11400Uruguay Área de Radiofarmacia Centro de Investigaciones Nucleares-Facultad de CienciasMataojo 2055Montevideo CP 11400Uruguay química Bioanalítica Instituto Polo Tecnológico de Pando-Facultad de QuímicaUdelaRBy Pass de Pando y Ruta 8Pando-Canelones CP 91000Uruguay laboratorio de Nacional de Nanotecnología-CeNAT-CONARE Costa Rica 1174-1200San JoséCP 10109Costa Rica laboratorio de Polímeros POLIUNA-Escuela de Química Universidad NacionalHerediaSan JoséCP 86-3000Costa Rica

The biomass industrialization valorisation of grains and cereals is considered an opportunity for the countries where agro-industrial activity is one of its main economic activities,rendering new higher-value products with a concomitant solution to waste accumulation *** that end,in this work we describe and characterise bioactive compounds generation from rice husk by semisolid fermentation,obtained from 500 g of the material at room temperature and 60%humidity with mixed cultures of Phanerochaete chrysosporium and Gloeophyllum *** extract was evaluated in different situations:murine mammary tumour cells(4T1),normal cells(NIH 3T3)and in Lactobacillus acidophilus,and Trichoderma *** results exhibited that the extract inhibited 4T1 cells at concentrations higher than 20μg/mL,but did not inhibit normal cells,and displayed germicide activity after 3 days *** propose that these functionalized compounds have a potential application in industry/agriculture/medicine obtained from rice husk waste.

关键词： Biorefinery rice husk bioactive compounds valorisation of biomass veratryl alcohol

Artificial Triterpenoid Fatty Acid Ester Isolated From the Leaves of Phytolacca icosandra L

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Natural Products and Bioprospecting 2020年第4期10卷 221-225页

作者： Elier Galarraga Andersson Mavares Neudo Urdaneta Rafael ERodríguez-Lugo Juan Manuel Amaro-Luis departamento de química.Edificio de química Y Procesos Universidad Simón Bolívar(USB)Apartado 89000.Caracas-1080AVenezuelaUSA laboratorio de química Bioinorgánica Centro de QuímicaInstituto Venezolano de Investigaciones Científicas(IVIC)VenezuelaCaracas 1020-AUSA laboratorio de Productos Naturales Departamento de Química.Facultad de CienciasUniversidad de Los Andes(ULA)MéridaVenezuela-5101USA

The methanol extract form the leaves of Phytolacca icosandra L.,afforded the unprecedented artificial triterpenoid fatty acid ester 1 derived from the new natural triterpenoid phytolaccagenic acid 3-O-myristate(1a),along with the three known triterpenoids serjanic,acinosolic and phytolaccagenic acid(2-4).Their structures were stablished by HR-EI-MS,1D and 2D NMR *** possible mechanistic formation of 1 is proposed,and the in vitro toxicity of all compounds was assessed using the brine shrimp lethality assay(BSLA).

关键词： Phytolacca icosandra.triterpenoid fatty acid ester NMR artificial products BSLA

Europium recovery process by means of polymeric nanoparticles functionalized with acrylic acid,curcumin and fumaramide

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Journal of Rare Earths 2024年第10期42卷 1950-1959页

作者： P.A.Martínez-Montoya J.M del Río A.de J.Morales-Ramirez M.Corea Escuela Superior de Ingeniería química e Industrias Extractivas ESIQIE-IPNDepartamento de Ingeniería Metalúrgica UPALM S/N Col.LindavistaGustao A.MaderoCDMXC.P.07738Mexico Escuela Superior de Ingenieria química e Industrias Extractivas ESIQIE-IPNLaboratorio de Investigación en Polímeros y NanomaterialesUPALM S/N Col.LindavistaGustavoA.MaderoCDMXC.P.07738Mexico Centra de Investigación e Innovación Tecnológica CIITEC-IPNCda.de CECATIs/nSanta CatarinaAzcapotzalcoC.P.02250CDMXMexico

Polymeric nanoparticles of poly(methyl methacrylate)were obtained by emulsion polymerization techniques in a proce ss of two *** particles were functionalized with acrylic acid,curcumin,and fumaramide and three series of polymeric particles were *** incorporation of functional groups was confirmed by Fourier transform-infrared spectrosocopy(FT-IR)and ultraviolet-visible(UV-Vis)*** spherical morphology of particles with an average diameter of 100 nm was observed by scartning electron microscopy(SEM).The polymeric materials were used for recovery of[Eu]from synthetic *** nanoparticles show excellent chelation capacity to trap rare-earth ions,because they recover more than 85%of[Eu]at pH of *** images of SEM after extraction process show arrays between particles with larger average particle sizes to 1.5 *** addition,the particles have a good stripping capacity,exceeding 50%of it,maintaining their homogeneity in morphology and good stability in dispersion for the recovery and stripping processes.A pseudo-second model order is obtained for the extraction and stripping processes while the best results of stripping process are obtained at pH of 6.

关键词： [Eu]recovery Chelating effect Extraction process Stripping process Emulsion polymerization Rare earths

Soil Formation of "Atlantic Rankers" from NW Spain—A High Resolution Aluminium and Iron Fractionation Study

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Pedosphere 2008年第4期18卷 441-453页

作者： J. KAAL M. COSTA-CASAIS C. FERRO-VZquEZ X. PONTEVEDRA-POMBAL A. MARTINEZ-CORTIZAS Instituto de Estudios Galegos Padre Sarmiento Laboratorio de Arqueología del Paisaje (LAr) IEGPS-CSIC-XuGaRúa San Roque 2 15704 Santiago de Compostela (Spain). departamento de Edafología y química Agrícola Fac. Biología Universidad de Santiago (Spain)

Atlantic rankers belong to the group of ＂cryptopodzolic rankers＂, which are ubiquitous in the mountainous cool/temperate humid regions of Western Europe. The rankers of Galicia （NW Spain） formed by thousands of years of colluviation. The preponderance of Al-stabilised organic matter （OM） masks the horizonation and polycyclic character （i.e., stratification） of these soils. Cryptopodzolic rankers are generally thought to be the outcome of podzolisation. This soil type is part of the recent discussion on how to classify soils developed from nonvolcanic parent material having andic properties. To better understand the formation processes of these soils, the Al and Fe fractionation of four typical Atlantic rankers were studied by selective dissolution in acid NH4-oxalate, Na-pyrophosphate and the chlorides of K, La and Cu. A high-resolution sampling approach allowed us to investigate the soils in greater detail than simply sampling by horizon. The rankers studied display a distribution of Fe- and AI-OM complexes that is typical of cryptopodzolic soils. However, these organomineral associations were probably immobile due to the high Al saturation. We argue that the soils owe their characteristic chemical status to external factors rather than to translocation of organomineral associations： variations in AI-OM concentrations could be linked to changes in weathering/leaching intensity and colluviation rates caused by anthropogenic disturbances or changes in regional climate regime.

关键词： Al fractionation colluviation cryptopodzolic soil podzolisation ranker