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Single Step Microwave Assisted Synthesis and Antimicrobial Activity of Silver, Copper and Silver-Copper Nanoparticles

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j.urnal of Materials Science and Chemical Engineering 2020年第8期8卷 13-29页

作者： Myrna Reyes-Blas Nadj. M. Maldonado-Luna Carla M. Rivera-Quiñones Ana L. Vega-Avila Felix R. Roman-Velázquez oscar j. perales-perez Department of Chemistry University of Puerto Rico at Mayagüez Mayaguez USA Department of Mechanical Engineering University of Puerto Rico at Mayagüez Mayaguez USA Department of Chemical Engineering University of Puerto Rico at Mayagüez Mayaguez USA Department of Engineering Science & Materials University of Puerto Rico at Mayagüez Mayaguez USA

Copper and silver nanoparticles were synthesized and characterized in two minutes at 175°C in a one-step synthesis using a modified polyol (ethylene glycol) method and a microwave heating process. We successfully synthesized spherical Silver (Ag) and Copper nanoparticles (CuNP) with a crystallite size of less than 10 nm, as well as irregular silver-copper nanoparticles (AgCuNP) with a crystallite size of less than 15 nm, as confirmed by X-Ray Diffraction (XRD) and High-Resolution Transmission Electron Microscopy (HRTEM). The successful synthesis of AgCuNP with 1:1 molar ratio and constituted by 51.74% of copper and 48.26% of silver was corroborated using the Energy Dispersive X-ray (EDX) mapping technique. The AgNP and AgCuNP exhibited more stability in suspension, in comparison to CuNP, as observed by continuously monitoring the absorbance with UV-Vis spectroscopy for 12 days. Furthermore, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AgNP, CuNP, and AgCuNP were determined, against Gram-negative and Gram-positive bacteria, and yeast. The obtained MIC and MBC values indicate that AgCu nanoparticles exhibited bactericidal properties greater than its constituents. On the contrary, antifungal activity of AgCuNP against yeast was not observed.

关键词： Ag Nanoparticles Cu Nanoparticles Microwave Synthesis Modified Polyol Method Antimicrobial Properties AgCu Nanoparticles

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Bile-acid-induced cell inj.ry and protection

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World j.urnal of Gastroenterology 2009年第14期15卷 1677-1689页

作者： Maria j.perez oscar Briz Research Unit University Hospital of Salamanca Laboratory of Experimental Hepatology and Drug Targeting CIBERehd University of Salamanca E.D. 129 37007 Salamanca Spain

Several studies have characterized the cellular and molecular mechanisms of hepatocyte inj.ry caused by the retention of hydrophobic bile acids （BAs） in cholestatic diseases. BAs may disrupt cell membranes through their detergent action on lipid components and can promote the generation of reactive oxygen species that, in turn, oxidatively modify lipids, proteins, and nucleic acids, and eventually cause hepatocyte necrosis and apoptosis. Several pathways are involved in triggering hepatocyte apoptosis. Toxic BAs can activate hepatocyte death receptors directly and induce oxidative damage, thereby causing mitochondrial dysfunction, and induce endoplasmic reticulum stress. When these compounds are taken up and accumulate inside biliary cells, they can also cause apoptosis. Regarding extrahepatic tissues, the accumulation of BAs in the systemic circulation may contribute to endothelial inj.ry in the kidney and lungs. In gastrointestinal cells, BAs may behave as cancer promoters through an indirect mechanism involving oxidative stress and DNA damage, as well as acting as selection agents for apoptosis-resistant cells. The accumulation of BAs may have also deleterious effects on placental and fetal cells. However, other BAs, such as ursodeoxycholic acid, have been shown to modulate BA-induced inj.ry in hepatocytes. The maj.r beneficial effects of treatment with ursodeoxycholic acid are protection against cytotoxicity due to more toxic BAs; the stimulation of hepatobiliary secretion; antioxidant activity, due in part to an enhancement in glutathione levels; and the inhibition of liver cell apoptosis. Other natural BAs or their derivatives, such as cholyI-N- methylglycine or pharmacological properties. cholylsarcosine, interest owing have also aroused to their protective

关键词： Apoptosis Cholestasis Liver Necrosis Oxidative stress Ursodeoxycholic acid

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The cold-induced factor CBF3 mediates root stem cell activity,regeneration,and developmental responses to cold

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Plant Communications 2023年第6期4卷 197-211页

作者： Pablo perez-Garcia Ornella Pucciariello Alvaro Sanchez-Corrionero j.vier Cabrera Cristina del Barrio j.an Carlos del Pozo Mariano perales Krzysztof Wabnik Miguel A.Moreno-Risueno Centro de Biotecnologíay Genómica de Plantas(Universidad Politécnica de Madrid(UPM)–Instituto Nacional de Investigacióny Tecnología Agraria y Alimentaria–CSIC(INIA-CSIC)) MadridSpain

Plant growth and development involve the specification and regeneration of stem cell niches(SCNs).Although plants are exposed to disparate environmental conditions,how environmental cues affect developmental programs and stem cells is not well *** stem cells are accommodated in meristems in SCNs around the quiescent center(QC),which maintains their *** a combination of genetics and confocal microscopy to trace morphological defects and correlate them with changes in gene expression and protein levels,we show that the cold-induced transcription factor(TF)C-REPEAT BINDING FACTOR 3(CBF3),which has previously been associated with cold acclimation,regulates root development,stem cell activity,and ***3 is integrated into the SHORT-ROOT(SHR)regulatory network,forming a feedback loop that maintains SHR ***3 is primarily expressed in the root endodermis,whereas the CBF3 protein is localized to other meristematic tissues,including root *** of cbf3-1 using a wild-type CBF3 gene and a CBF3 fusion with reduced mobility show that CBF3 movement capacity is required for SCN patterning and regulates root ***,cold induces CBF3,affecting QC ***,exposure to moderate cold around 10℃–12℃promotes root regeneration and QC respecification in a CBF3-dependent manner during the recuperation *** contrast,CBF3 does not appear to regulate stem cell survival,which has been associated with recuperation from more acute cold(-4℃).We propose a role for CBF3 in mediating the molecular interrelationships among the cold response,stem cell activity,and development.

关键词： stem cells regeneration organ patterning protein movement cell fate low temperature

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Further understanding of mechanisms involved in liver cancer chemoresistance

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Hepatoma Research 2017年第1期3卷 22-26页

作者： oscar Briz Maria j.perez j.se j.G.Marin Department of Physiology and Pharmacology University of Salamanca37007 SalamancaSpain

An important limitation for the success of chemotherapy in the treatment of primary liver cancer (hepatocellular carcinoma,hepatoblastoma and cholangiocarcinoma) is the marked efficacy of mechanisms of chemoresistance (MOC).These have been previously classified into five groups depending on whether they result in:a reduced drug uptake or enhanced drug export (MOC-1);poor intracellular activation of prodrugs or higher inactivation of active drugs (MOC-2);changes in the molecular targets that impairs the action of the drug by increasing the activity of the metabolic route to be inhibited or stimulating alternative routes (MOC-3);ability of tumor cells to repair drug-induced modifications in the target molecule,usually DNA (MOC-4);and the activation or inhibition of intracellular signaling pathways that lead to a change in the balance between proand anti-apoptotic factors favoring tumor cell survival (MOC-5).Nevertheless,novel information appeared over the last few years has recommended to consider two additional groups,MOC-6 and MOC-7,based on changes in tumor microenvironment,mainly hypoxia and acidity,and epithelial-mesenchymal transition,*** contribute to the defensive armamentaria developed or enhanced in liver cancer cells to resist the pharmacological attack,which accounts for a negligible beneficial effect of commonly used antitumor drugs and only a modest response to novel targeted therapies based on tyrosine kinase inhibitors,such as ***,further advances are urgently needed to better understand the molecular and cellular bases of the chemoresistant barrier and help scientists in this field to develop new tools able to overcome cancer cell defenses.

关键词： Chemotherapy cholangiocarcinoma hepatoblastoma hepatocellular carcinoma tumor environment epithelial-mesenchymal transition

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Improved Low-Temperature Aqueous Synthesis of ZnO Nanorods and Their Use in SERS Detection of 4-ABT and RDX

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Materials Sciences and Applications 2013年第1期4卷 29-38页

作者： Marcia del R.Balaguera-Gelves oscar j.perales-Pérez Surinder P.Singh j.sé A.j.ménez j.aquín A.Aparicio-Bolanos Samuel P.Hernández-Rivera Department of Chemistry University of Puerto Rico-MayaguezMayagüezPuerto Rico Department of Engineering Science and Materials University of Puerto Rico-MayaguezMayagüezPuerto Rico Department of Chemistry University of North FloridaJacksonvilleUSA Department of Chemistry and Physics University of Puerto Rico-PoncePoncePuerto Rico

The growth-controlled synthesis of zinc oxide nanorods (ZnO NR) in the aqueous phase has been investigated. The rods were grown on ZnO films previously deposited onto Si(100) and indium tin oxide (ITO) substrates by RF magnetron sputtering. The formation of the rods took place in the presence of hexamethylenetetramine (HMT) as habit-control reagent. The grains in the base ZnO film acted as seeds that promoted the longitudinal growth of the oxide. As-synthesized base films and rods were characterized by X-ray diffraction, scanning electron microscopy (SEM), field emission SEM, optical absorption and photoluminescence spectroscopy techniques. Subsequently, a wet chemistry procedure was performed to achieve ZnO NR growth. This methodology was conducive to the formation of rods of a relatively narrow distribution of diameters (60 - 70 nm) with lengths in the 1 - 3 μm range. Photoluminescence spectra were characterized by a dominant near-band-edge (NBE) peak followed by a green luminescence (GL) broad band, indicative of higher oxygen vacancy concentration in the ZnO NR grown on ZnO/ITO in comparison with those grown on ZnO/Si(100). A UV process was used for coating the ZnO NR with gold (Au). Au coating on ZnO NR was used to evaluate the detection capability by SERS of different analytes such as: 4-aminobenzenethiol (4-ABT) and 1,3,5-trinitroperhydro-1,3,5- triazine (RDX) at low levels. A strong SERS Raman spectrum was observed for 4-ABT. A limit of detection (LOD) of 1 × 10-8M for 4-ABT was achieved corresponding to a minimum of 5.4 × 105molecules detected under the experimental conditions at excitation wavelength of 785 nm with a sensitivity of the ZnO NR in the range of 1.1 × 10-16g under the laser spot.

关键词： ZnO Nanorods Sputtering SERS 4-ABT RDX

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