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Thermo-Stability of Natural Products Based on Chlorophyll Species Embedded in Silica Xerogel

American Journal of Analytical Chemistry 2016年第4期7卷 356-362页

作者： José Martínez-Mendoza Erika espericueta-gonzález diana espericueta gonzález Gerardo Ortega-Zarzosa Azdrubal Lobo Guerrero Departamento de Físico-Matemáticas Universidad Autónoma de San Luis Potosí San Luis Potosí México Facultad de Ciencias Universidad Autónoma de San Luis Potosí San Luis Potosí México Facultad de Ingeniería Universidad Autónoma de San Luis Potosí San Luis Potosí México Doctorado Institucional de Ciencia e Ingeniería de Materiales Universidad Autónoma de San Luis Potosí San Luis Potosí México Instituto de Física Universidad Autónoma de San Luis Potosí San Luis Potosí México

This work studied the thermostability and the biostability of chlorophyll species obtained from an extract of spinach leaves embedded in a silica xerogel matrix. The analysis was done by monitoring the photosystem II (PSII) using fluorescence spectroscopy. Samples were prepared using the sol gel method with a molar ratio of ethanol/H2O/TEOS of 4:11.6:1. Then, silica xerogel matrix was loaded with an extract of spinach leaves, obtained in dark conditions. The measurement of the fluorescence spectra was done at selected temperatures to the corresponding non-physiological regimen. Results indicate that the PSII band position remains unchanged when heat treatment temperature increases up 200°C. For temperatures above 100?C, the fluorescence intensity diminishes linearly when the temperature increases. The photosystem II embedded in silica xerogel matrix is decomposed at temperatures above 200°C.

关键词： Chlorophyll Structure Biostability Sol-Gel

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Structural Comportment of Extract of Bougainvillea xbuttiana Flower Incorporated in Silica Xerogel Matrix

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American Journal of Plant Sciences 2016年第6期7卷 828-833页

作者： José Martínez-Mendoza Erika espericueta-gonzález diana espericueta-gonzález Gerardo Ortega-Zarzosa Azdrubal Lobo Guerrero Departamento de Físico-Matemáticas Universidad Autónoma de San Luis Potosí San Luis Potosí México Facultad de Ciencias Universidad Autónoma de San Luis Potosí San Luis Potosí México Facultad de Ingeniería Universidad Autónoma de San Luis Potosí San Luis Potosí México Doctorado Institucional de Ciencia e Ingeniería de Materiales Universidad Autónoma de San Luis Potosí San Luis Potosí México Instituto de Física Universidad Autónoma de San Luis Potosí San Luis Potosí México

Measurement of the fluorescence comportment of Bougainvillea xbuttiana flowers embedded in silica xerogels matrix prepared with two different water to tetraethyl-orthosilicate [Si(OC2H5)4] ratio molar of 11 and 5, without heat-treatment, we report the grade of biostability of compound. The structural comportment for the PSI and PSII present in Bougainvillea flower is similar to the structural comportment for these photosystems present in leaves when they are incorporated on inorganic matrix such as silica xerogels. The contribution of the natural pigment of this kind of flower such as betalains which consist of betaxanthins and betacyanins, determines their colors contributed in the range of wavelength from about 550 nm to 660 nm.

关键词： Betalaine Chlorophyll Structure Biostability Sol-Gel

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Comparing the biogeochemical functioning of two arid subtropical coastal lagoons:the effect of wastewater discharges

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Ecosystem Health and Sustainability 2021年第1期7卷 49-60页

作者： Julio Medina-Galván Carmen Cristina Osuna-Martínez Gustavo Padilla-Arredondo Martín Gabriel Frías-espericueta Ramón Héctor Barraza-Guardado JoséAlfredo Arreola-Lizárraga Facultad de Ciencias del Mar Universidad Autónoma de SinaloaMazatlánMéxico Programa de Planeación Ambiental y Conservación Centro de Investigaciones Biológicas del NoroesteS.C.GuaymasMéxico Departamento de Investigaciones Científicas y Tecnológicas de la Universidad de Sonora HermosilloMéxico

Nutrient flux,net metabolism,and N2 fixation and denitrification processes were estimated and compared in two semi-arid subtropical coastal lagoons in the Gulf of California:El Soldado(ES),where no wastewater is discharged,and El Rancho(ER),where shrimp farm effluents are regularly *** processes were evaluated with the LOICZ *** time was<2 days in both *** fluxes were higher in ER than in ES and both systems acted as nutrient sinks for most of the *** showed a larger nutrient flow rate in the summer and autumn due to the input of shrimp-farm *** fluxes increased in both ER and ES in the winter in response to the increased nutrient supply from coastal *** and ES both showed autotrophic metabolism and N2 fixation in the spring,autumn,and winter,but heterotrophic metabolism and denitrification in the *** dominated in ER(−2.21 mmol m^(2)day^(−1))and values were higher than those estimated in ES(−0.45 mmol m^(2)day^(−1)).The comparative analysis between ES and ER evidenced the significant changes in its biogeochemical performance caused by the input of anthropogenic nutrients,and can orient the environmental management of coastal lagoons.

关键词： Coastal lagoons nutrient budgets net ecosystem metabolism Gulf of California

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Effect of Aging in the Structure of Silica Xerogels with Incorporation of Extract’s Leaves

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New Journal of Glass and Ceramics 2011年第1期1卷 7-12页

作者： José R. Martínez Erika espericueta Gerardo Ortega-Zarzosa 不详

The spectral fluorescence characteristics of extracts leaves embedded in silica xerogel matrix promoted by aged time was studied. We obtain a higher PSII stability for extract of leaves embedded in xerogel matrix, with concentration of 8 g / 20 ml and water to TEOS molar ratio of 11, which remain bioactive over a very long period of time, whereas for a water to TEOS molar ratio of 5 a blue-shift fluorescence is observed indicating the PSII denaturizing and formation of fluorescing aggregates associated with the activation of carotenoids radicals.

关键词： Fluorescence Spectra Sol-Gel Chlorophyll Extract Leaves Photosystem II

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