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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)

Progesterone effects on the oligodendrocyte linage: all roads lead to the progesterone receptor

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Neural Regeneration Research 2019年第12期14卷 2029-2034页

作者： Ignacio Jure Alejandro F. de Nicola Florencia Labombarda laboratorio de Bioquímica Neuroendocrina Instituto de Biología y Medicina Experimental CONICET Buenos Aires Argentina departamento de Bioquímica Humana Facultad de Medicina Universidad de Buenos Aires Buenos Aires Argentina

A new role has emerged for progesterone after discovering its potent actions away from reproduction in both the central and the peripheral nervous system. The aim of the present report is to discuss progesterone’s mechanisms of action involved in myelination, remyelination and neuroinflammation. The pivotal role of the classic progesterone receptor is described and evidence is compiled about progesterone’s direct effects on oligodendrocyte linage and its indirect effects on oligodendrocyte precursor cell differentiation by decreasing the neuroinflammatory environment.

关键词： progesterone progesterone receptor oligodendrocyte differentiation myelination remyelination neuroinflammation

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

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

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

Influence of dissolved organic matter character on mercury incorporation by planktonic organisms: An experimental study using oligotrophic water from Patagonian lakes

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Journal of Environmental Sciences 2013年第10期25卷 1980-1991页

作者： María C.Diéguez Claudia P.Queimalios Sergio Ribeiro Guevara Mark Marvin-DiPasquale Carolina Soto Crdenas María A.Arribre laboratorio de Fotobiología INIBIOMA CONICET-UNComahue laboratorio de Fotobiolog INIBIOMA CONICET-UNComahue laboratorio de Anlisis por Activación Neutrónica Centro Atómico Bariloche CNEA United States Geological Survey laboratorio de Anlisis por Activacio Neutrónica Centro Atómico Bariloche CNEA

Ligands present in dissolved organic matter （DOM） form complexes with inorganic divalent mercury （Hg^2＋） affecting its bioavailability in pelagic food webs. This investigation addresses the influence of a natural gradient of DOM present in Patagonian lakes on the bioaccumulation of Hg^2＋（the prevailing mercury species in the water column of these lakes） by the algae Cryptomonas erosa and the zooplankters Brachionus calyciflorus and Boeckella antiqua. Hg^2＋ accumulation was studied through laboratory experiments using natural water of four oligotrophic Patagonian lakes amended with^197Hg^2＋. The bioavailability of Hg^2＋ was affected by the concentration and character of DOM. The entrance of Hg^2＋ into pelagic food webs occurs mostly through passive and active accumulation. The incorporation of Hg^2＋ by Cryptomonas, up to 27% of the Hg^2＋ amended, was found to be rapid and dominated by passive adsorption, and was greatest when low molecular weight compounds with protein-like or small phenolic signatures prevailed in the DOM. Conversely, high molecular weight compounds with a humic or fulvic signature kept Hg^2＋ in the dissolved phase, resulting in the lowest Hg^2＋ accumulation in this algae. In Brachionus and Boeckella the direct incorporation of Hg from the aqueous phase was up to 3% of the Hg^2＋ amended. The dietary incorporation of Hg^2＋ by Boeckella exceeded the direct absorption of this metal in natural water, and was remarkably similar to the Hg^2＋ adsorbed in their prey. Overall, DOM concentration and character affected the adsorption of Hg^2＋ by algae through competitive binding, while the incorporation of Hg^2＋ into the zooplankton was dominated by trophic or dietary transfer.

关键词： mercury dissolved organic matter plankton mercury incorporation Patagonian lakes Argentina

Progesterone for the treatment of central nervous system disorders: the many signaling roads for a single molecule

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Neural Regeneration Research 2020年第10期15卷 1846-1847页

作者： Susana Laura González Universidad de Buenos Aires Facultad de Medicina Departamento de Bioquímica Humana Buenos Aires laboratorio de Nocicepción y Dolor Neuropático Instituto de Biología y Medicina Experimental

Central nervous system(CNS)injuries and neurodegenerative diseases show a broad spectrum of common pathophysiological processes,including oxidative stress,neuroinflammation,excitotoxicity,demyelination and neurotransmission *** the past decades,valuable experimental investigations have helped to clarify the role and timing of these multiple molecular and cellular mechanisms in each of these particular disorders,which usually overlap and critically contribute to long-term ***,up to now,no definite cures or effective disease-modifying therapies are available for any of these *** has led to an active search of novel therapeutic approaches,including the repositioning of existing drugs for new indications,as a valid approach to promptly move candidate molecules to clinical trials.

关键词： injuries disorders drugs

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

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