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

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 josé A.jiménez joaquín 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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Simulating FAS-induced apoptosis by using p systems

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progress in Natural Science:Materials International 2007年第4期17卷 424-431页

作者： Smitha Cheruku Andrei pǎun Francisco j. Romero-Campero Mario j. pérez-jiménez oscar H. Ibarra Department of Computer Science/IfM Louisiana Tech UniversityP.O. Box 10348RustonLA 71272USA Department of Computer Science and Artificial Intelligence University of SevilleAvda. Reina Mercedes s/n 41012SevillaSpain Department of Computer Science University of California-Santa BarbaraSanta BarbaraCA 93106USA

In contrast to differential equations, p systems are an unconventional model of computation which takes into consideration the discrete character of the quantity of components and the inherent randomness that exists in biological phenomena. The key feature of p systems is their compartmentalised structure which represents the heterogeneity of the structural organisation of the cells, and where one can take into account the role played by membranes in the functioning of the system, for example signalling at the cell surface, selective uptake of substances from the media, diffusion across different compartments, etc. We show here that p systems can be a reliable tool for Systems Biology and could even outperform in some cases the current simulation techniques based on differential equations. We will also use a strategy based on the well known Gillespie algorithm but running on more than one compartment called Multi-compartmental Gillespie Algorithm.

关键词： FAS-induced apoptosis p systems deterministic waiting times algorithm multi-compartmental Gillespie algorithm.

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Bile-acid-induced cell injury and protection

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World journal 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 injury 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 injury 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 injury in hepatocytes. The major 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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Simultaneous Raman and reflection UV/Vis absorption spectroelectrochemistry

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Nano Research 2022年第6期15卷 5340-5346页

作者： Sheila Hernandez juan V.perales-Rondon Aranzazu Heras Alvaro Colina Department of Chemistry Universidad de BurgosPza.Misael Banuelos s/ñBurgos E-09001Spain Department of Analytical Chemistry Physical Chemistry and Chemical EngineeringUniversity of Alcala.Ctra.Madrid-BarcelonaKm.33.600MadridAlcaláde Henares E-28871Spain

In the present work,a new combination of Raman and ultraviolet and visible(UV/Vis)absorption spectroelectrochemistry in reflection mode is *** new experimental setup allows obtaining the two kinds of spectroscopic data without interferences concomitantly with the electrochemical *** the best of our knowledge,it is the first time to report the simultaneous obtention of electrochemical,electronic,and vibrational information in the same *** new combination provides time-resolved information about the processes that are taking place on the electrode/solution interface which has significant implications in different fields of chemistry,such as modification of electrodes,studies of electrocatalytic reaction mechanisms,development of sensors,among *** different systems were used to demonstrate the advantages and capabilities of the brand-new technique,namely,the oxidation of potassium ferrocyanide,an out-sphere system that is usually employed in the validation of SEC techniques,and the electrochemical-surface enhanced Raman spectroscopy(EC-SERS)detection of crystal violet by in-situ formation of the silver SERS substrate,where the UV/Vis spectra were used to follow the formation of the SERS substrate,whereas the Raman response of a probe molecule was used to confirm either the formation of a nanostructured surface and to obtain the fingerprint of the molecule with a high time *** brand-new experimental setup has shown to be useful,versatile,robust,compact,and easy to use for future applications.

关键词： spectroelectrochemistry surface enhanced Raman spectroscopy(SERS) Raman ultraviolet and visible(UV/Vis)absorption nanoparticles

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Introduction to 3D reconstruction of macromolecules using single particle electron microscopy

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Acta pharmacologica Sinica 2005年第10期26卷 1153-1164页

作者： oscar LLORCA Centro de lnvestigaciones Biológicas Consejo Superior de Investigaciones Científicas Ramiro de Maeztu 9 Campus Universidad Complutense 28040 Madrid Spain

Single-particle electron microscopy has now reached maturity, becoming a commonly used method in the examination of macromolecular structure. Using a small amount of purified protein, isolated molecules are observed under the electron microscope and the data collected can be averaged into a 3D reconstruction. Single-particle electron microscopy is an appropriate tool for the analysis of proteins that can only be obtained in modest quantities, like many of the large complexes currently of interest in biomedicine. Whilst the use of electron microscopy expands, new methods are being developed and improved to deal with further challenges, such as reaching higher resolutions and the combination of informa tion at different levels of structural detail. More importantly, present methodology is still not robust enough when studying certain "tricky" proteins like those displaying extensive conformational flexibility and a great deal of user expertise is required, posing a threat to the consistency of the final structure. This mini review describes a brief outline of the methods currently used in the 3D analysis of macromolecules using single-particle electron microscopy, intended for those first approaching this field. A summary of methods, techniques, software, and some recent work is presented. The spectacular improvements to the technique in recent years, its advantages and limitations compared to other structural methods, and its future developments are discussed.

关键词： single particle electron microscopy 3D reconstruction cryoelectron microscopy image processing DNA-pK

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Enhanced photoluminescence of a microporous quantum dot color conversion layer by inkjet printing

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Nano Research 2024年第8期17卷 7717-7725页

作者： junchi Chen Qihao jin Yidenekachew.j.Donie Orlando.T.perales Dmitry Busko Bryce.S.Richards Uli Lemmer Light Technology Institute(LTI) Karlsruhe Institute of Technology(KIT)Engesserstrasse 1376131 KarlsruheGermany Department of Chemical Engineering and Materials Science University of Minnesota(UMN)421 Washington Ave.SEMinneapolisMN 55455-0132USA Institute for Microstructure Technology Karlsruhe Institute of Technology(KIT)Hermann-von-Helmholtz-Platz 176344 Eggenstein-LeopoldshafenGermany

Owing to their high color purity,tunable bandgap,and high efficiency,quantum dots(QDs)have gained significant attention as color conversion materials for high-end display ***,inkjet-printed QD pixels show great potential for realizing full-color mini/micro-light emitting diode(micro-LED)-based *** a color conversion layer,the photoluminescence intensity of QDs is limited by the insufficient absorptance of the excitation light due to the lack of *** scatterers,such as titanium dioxide microparticles,have been applied after additional surface engineering for sufficient dispersity to prevent nozzle clogging in inkjet printing *** our work,as an alternative approach,we use inkjet printing for depositing a phase separating polymer ink based on polystyrene(pS)and polyethylene glycol(pEG).QD/polymer composite pixels with scattering micropores are *** morphology of the micropores can be tailored by the weight ratio between pS and pEG which enables the manipulation of scattering *** the presence of the microporous structure,the photoluminescence intensity of the QD film is enhanced by 110%in drop-cast films and by 35.3%in inkjet-printed QD pixel arrays compared to the reference samples.

关键词： porous structure inkjet printing phase separation quantum dots display technology

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Mapping aboveground biomass by integrating geospatial and forest inventory data through a k-nearest neighbor strategy in North Central Mexico

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journal of Arid Land 2014年第1期6卷 80-96页

作者： Carlos A AGUIRRE-SALADO Eduardo j TREVIO-GARZA oscar A AGUIRRE-CALDERóN javier jIMNEZ-prez Marco A GONZLEZ-TAGLE josé R VALDZ-LAZALDE Guillermo SNCHEZ-DíAZ Reija HAApANEN Alejandro I AGUIRRE-SALADO Liliana MIRANDA-ARAGóN Faculty of Forest Sciences Autonomous University of Nuevo Leon Faculty of Engineering Autonomous University of San Luis Potosi Forestry program Postgraduate College Haapanen Forest Consulting Faculty of Agronomy and Veterinary Autonomous University of San Luis Potosí

As climate change negotiations progress,monitoring biomass and carbon stocks is becoming an important part of the current forest ***,national governments are interested in developing forest-monitoring strategies using geospatial *** statistical methods for mapping biomass,there is a nonparametric approach called k-nearest neighbor(kNN).We compared four variations of distance metrics of the kNN for the spatially-explicit estimation of aboveground biomass in a portion of the Mexican north border of the intertropical *** derived,climatic,and topographic predictor variables were combined with the Mexican National Forest Inventory(NFI)data to accomplish the *** of distance metrics applied into the kNN algorithm was evaluated using a cross validation leave-one-out *** results indicate that the Most Similar Neighbor(MSN)approach maximizes the correlation between predictor and response variables(r=0.9).Our results are in agreement with those reported in the *** findings confirm the predictive potential of the MSN approach for mapping forest variables at pixel level under the policy of Reducing Emission from Deforestation and Forest Degradation(REDD+).

关键词： k-nearest neighbor Mahalanobis most similar neighbor MODIS BRDF-adjusted reflectance forest inventory the policy of Reducing Emission from Deforestation and Forest Degradation

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Improving colorectal cancer screening programs

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World journal of Gastroenterology 2024年第22期30卷 2849-2851页

作者： oscar j Cordero Lucia Mosquera-Ferreiro Iria Gomez-Tourino Department of Biochemistry and Molecular Biology University of Santiago de CompostelaSantiago de Compostela 15782Spain Centre for Research in Molecular Medicine and Chronic Diseases(CiMUS) University of Santiago de CompostelaSantiago de Compostela 15782GaliciaSpain

In this editorial we comment on the article by Agatsuma et al published in the World journal of *** suggest policies for more effective colorectal *** is the main policy that has led to lower mortality rates in later years among the population that was eligible for *** is the gold standard tool for screening and has preventive effects by removing precancerous or early malignant ***,colonoscopy is an invasive process,and fecal tests such as the current hemoglobin immunodetection were developed,followed by endoscopy,as the general tool for population screening,avoiding logistical and economic *** so,participation and adherence rates are *** screening options are being developed with the idea that if people could choose between the ones that best suit them,participation in population-based screening programs would *** tests,such as a recent one that detects cell-free DNA shed by tumors called circulating tumor DNA,showed a similar accuracy rate to stool tests for cancer,but were less sensitive for advanced precancerous *** the time when the crosstalk between the immune system and cancer was being established as a new hallmark of cancer,novel immune system-related biomarkers and information on patients’immune parameters,such as cell counts of different immune populations,were studied for the early detection of colorectal cancer,since they could be effective in asymptomatic people,appearing earlier in the adenoma-carcinoma development compared to the presence of fecal ***26,for example,detected 80.37%of advanced *** reach as many eligible people as possible,starting at an earlier age than current programs,the direction could be to apply tests based on blood,urine or salivary fluid to samples taken during routine visits to the primary health system.

关键词： Mortality rates Colorectal cancer Screening Biomarker Fecal hemoglobin immunodetection Soluble sCD26 Colonoscopy Immunoscores

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Simultaneous determination of kolliphor HS15 and miglyol 812 in microemulsion formulation by ultra-high performance liquid chromatography coupled with nano quantity analyte detector

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journal of pharmaceutical Analysis 2016年第1期6卷 11-17页

作者： Honggen Zhang ZhenyuWang oscar Liu Merck Research Laboratories Merck & Co. Inc. Rahway NJ 07065 USA

A novel method for simultaneous determination of kolliphor HS15 and miglyol 812 in microemulsion formulation was developed using ultra-high performance liquid chromatography coupled with a nano quantitation analytical detector （UHpLC-NQAD）. All components in kolliphor HS15 and miglyo1812 were well separated on an Acquity BEH C18 column. Mobile phase A was 0.1% trifluoroacetic acid （TFA） in water and mobile phase B was acetonitrile. A gradient elution sequence was programed initially with 60% organic solvent, slowly increased to 100% within 8 min. The flow rate was 0.7 mL/min. Good linearity （r 〉 0.95） was obtained in the range of 27.6-1381.1 μg/mL for polyoxyl 15 hydroxystearate in kolliphor HS15, 0.8-202.0 μg/mL for caprylic acid triglyceride and 2.7-221.9μg/mL for capric acid triglyceride in miglyol 812. The relative standard deviations （RSD） ranged from 0.6% to 1.7% for intra-day precision and from 0.4% to 2.7% for inter-day precision. The overall recoveries （accuracy） were 99.7%-101.4% for polyoxyl 15 hydroxystearate in kolliphor HS15, 96.7%-99.6% for caprylic acid triglyceride, and 94.1%- 103.3% for capric acid triglyceride in miglyol 812. Quantification limits （QL） were determined as 27.6 μg/ mL for polyoxy115 hydroxystearate in kolliphor HS15, 0.8 μg/mL for caprylic acid triglyceride, and 2.7 μg/ mL for capric acid triglyceride in miglyol 812. No interferences were observed in the retention time ranges of kolliphor HSI5 and miglyol 812. The method was validated in terms of specificity, linearity, precision, accuracy, QL, and robustness. The proposed method has been applied to microemulsion for- mulation analyses with good recoveries （82.2%-103.4%）.

关键词： Kolliphor HS15 Miglyol 812 Ultra-high performance liquid chromato-graphy (UHpLC) Nano quantitation analytical detector(NQAD)

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Effect of rhenium on the microstructure and mechanical behavior of Fe–2.25Cr–1.6W–0.25V-0.1C bainitic steels

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journal of Materials Science & Technology 2017年第12期33卷 1487-1493页

作者： josé Antonio jiménez Manuel Carsí oscar Antonio Ruano Department of physical Metallurgy Centro Nacional de lnvestigaciones MetalurgicasC.S.I.CAvda.Gregorio del Amo 828040 MadridSpain

A new ferritic creep resistant steel has been developed by eliminating Nb and adding 1.5 mass % Re to a ferritic steel grade T/p23 with the aim of enhancing its mechanical properties at high *** ingots of both steels, new grade and ASTM T/p 23, were hot rolled at 900℃ and then submitted to a thermal treatment consisting of solubilization at 1050℃ and tempering at 700℃. Tempered bainitic microstructures obtained contain second phases reinforcing carbide particles, mainly M_6C and M_（23）C_6 at the boundaries of both, prior austenite grains and bainitic ferrite laths, as well as MC within the grains. Mechanical properties at temperatures ranging from 540 to 600℃ were studied by strain-ratechange tests in compression at strain rates between 10^（-7） and 10^（-4）s^（-1）. These tests showed high stress exponents（n ≥ 20） and activation energies（Q ≈ 400 k j/mol） for both alloys, which were associated with a dislocation movement mechanism with a strong interaction between dislocations and precipitates. On the other hand, a creep exponent of 5 was derived for the stress dependence of minimum creep rate from conventional-type creep tests at 600℃. Although this stress exponent is usually related to a dislocation climb controlled creep mechanism, remarkable microstructural degradation observed with increasing creep time makes difficult to elucidate the true deformation mechanism controlling creep.

关键词： Creep resistant steel T/p23 Thermal treatment Tempered bainite High temperature mechanical properties Creep

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