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1.
J Nanosci Nanotechnol ; 20(2): 709-718, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31383066

RESUMO

We report the preparation and characterization of a new heterostructured Ag-TiO2/ZnFe2O4 (ATZ) nanocomposite. X-ray diffraction (XRD) reveals the presence of spinel type ZnFe2O4 and anatase TiO2. Scanning electron microscope (SEM) images of ATZ nanocomposites show that Ag nanoparticles are successfully loaded on the composite Ag-TiO2 and is uniformly distributed on surface of ZnFe2O4 forming a nanocomposite with an approximate particle size of 44.8 nm. High-resolution transmission electron microscope (HR-TEM) analysis clearly indicates the particles with spherical and hexagonal structure and sizes of most of the particles are below 50 nm. Ultra violet-visible diffuse reflectance spectra (UV-vis-DRS) show that Ag-TiO2/ZnFe2O4 has increased visible absorption than TiO2. Photoluminescence (PL) spectra shows that the intensity of ATZ is low relative to prepared TiO2. The photocatalytic degradation of Reactive Yellow 86 (RY 86) dye was studied. Based on the band gap energies of TiO2 and ZnFe2O4, a mechanism of degradation is given. Photocatalytic activity results suggest that as-prepared ATZ shows higher photodegradation efficiency than pure TiO2. The main reactive oxidative species involved in the degradation and stability of photocatalyst were also investigated. ATZ shows higher electrocatalytic activity than TiO2 for methanol electrooxidation. The cytotoxicity of ATZ was analysed. Multifunctionality of ATZ makes it useful for environmental and biomedical applications.

2.
J Nanosci Nanotechnol ; 19(12): 8163-8171, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31196340

RESUMO

A simple and efficient one pot synthesis of 1,2,4,5-tetra substituted imidazoles is achieved by condensation-cyclization reaction of benzil, aromatic aldehyde, 2-amino ethyl pyrrolidine, ammonium acetate using fly ash loaded Bi2O3-ZnO. Different substituted aldehydes have been used in this reaction. The process is operationally simple, environmentally safe and has magnificent yield. Furthermore this catalyst can be recycled at least four times without any loss of activity.

3.
J Nanosci Nanotechnol ; 19(11): 7026-7034, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31039855

RESUMO

The hydrothermally synthesized CuWO4 nanoparticles (NPs) were characterized with different analysis such as X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), High Resolution Transmission Electron Microscopy (HRTEM), Energy Dispersive X-ray Spectroscopy (EDX), Cyclic Voltammetry (CV), UV-Visible and Photoluminescence (PL) analysis. The prepared CuWO4 NPs were examined with Electrochemical Impedance Spectroscopy (EIS). SEM images show that CuWO4 NPs are highly spherical shaped morphology and porous in nature. The optical band gap of prepared CuWO4 NPs is found to be 2.12 eV. Photodegradation of diclofenac sodium (DFS) (medical waste) in the aqueous medium with CuWO4 NPs under visible light irradiation shows 98% degradation. The CuWO4 NPs was stable up to 5th cycle it can be used as a reusable photocatalyst for the DFS degradation. The electrical conductivity and dielectric properties of the CuWO4 NPs at room temperature is analyzed by EIS studies. The bulk conductivity value of the prepared nanoparticles is 1.477×10-5 S/cm at room temperature. The conductivity of CuWO4 NPs is found to be due to electrons movement. The CuWO4 NPs shows higher photocatalytic and electrocatalytic activity for decomposition of DFS and methanol electro-oxidation in alkaline medium respectively.

4.
J Nanosci Nanotechnol ; 19(8): 5089-5099, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-30913824

RESUMO

The Activated Charcoal supported Bi2O3-ZnO (AC-BZ) nanocomposite is successfully synthesized by simple and efficient hydrothermal followed by thermal decomposition method. The addition of Activated charcoal into the Bi2O3-ZnO matrices increases the active sites and shows efficient catalytic activity upon the degradation of azo dyes, Rhodamine-B (Rh-B) and Trypan Blue (TB). Prepared photocatalysts further prove its ability by the way of structure and absorption capacity. For understanding the efficiency of photocatalyst, it was characterized by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Field Emission Transmission Electron Microscopy (FE-TEM), High Resolution Transmission Electron Microscopy (HR-TEM), Diffused Reflectance Spectroscopy (UV-DRS), Photo Luminescense spectroscopy (PL) and N2 adsorption- desorption isotherms (BET). The FESEM images of the activated charcoal supported Bi2O3-ZnO show a nanocomposite structure and reveal that most of particles have hexagonal and spherical type in nano range. Absorption range and band gap energy were examined by UV-DRS techniques, which indicate the photogenerated electrons and holes are responsible for better photocatalytic activity. The prepared AC-BZ nanocomposite has maximum efficiency at pH 7, and it shows enhanced degradation efficiency up to four cycles which proves reusability of the catalyst. The obtained catalyst shows higher efficiency in self cleaning property by forming maximum degree of contact angle when compared with pure ZnO and Bi2O3-ZnO. This work may provide new strategy for eco-friendly and cost effective photocatalysts for various applications.

5.
J Photochem Photobiol B ; 181: 53-58, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29501725

RESUMO

The present work reports the green synthesis of Zinc Oxide Nanoparticles (ZnO NPs) using aqueous Tabernaemontana divaricata green leaf extract. ZnO NPs have been characterized by X-ray diffraction (XRD), Ultra Violet-Visible (UV-Vis) studies, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Fourier Transform-Infra Red (FT-IR) analysis. XRD pattern analysis confirms the presence of pure hexagonal wurtzite crystalline structure of ZnO. The TEM images reveal the formation of spherical shape ZnO NPs with the sizes ranging from 20 to 50 nm. The FT-IR analysis suggests that the obtained ZnO NPs have been stabilized through the interactions of steroids, terpenoids, flavonoids, phenyl propanoids, phenolic acids and enzymes present in the leaf extract. Mechanism for the formation of ZnO NPs using Tabernaemontana divaricata as bioactive compound is proposed. As prepared ZnO NPs reveals antibacterial activity against three bacterial strains, Salmonella paratyphi, Escherichia coli and Staphylococcus aureus. The ZnO NPs shows higher antibacterial activity against S. aureus and E. coli and lesser antibacterial activity against S. paratyphi compared to the standard pharmaceutical formulation. Photocatalytic activity of synthesized ZnO NPs was analyzed for methylene blue (MB) dye degradation with sunlight. Almost complete degradation of dye occurred in 90 min. This nano-ZnO, prepared by eco-friendly method will be much useful for dye removal and bacterial decontamination.


Assuntos
Antibacterianos/química , Nanopartículas Metálicas/química , Tabernaemontana/química , Antibacterianos/síntese química , Antibacterianos/farmacologia , Catálise , Escherichia coli/efeitos dos fármacos , Química Verde , Azul de Metileno/química , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Fotólise/efeitos da radiação , Extratos Vegetais/química , Salmonella paratyphi A/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Luz Solar , Tabernaemontana/metabolismo , Termogravimetria , Difração de Raios X , Óxido de Zinco/química
6.
J Genet ; 96(5): 731-732, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29237878
7.
Strabismus ; 24(4): 178-183, 2016 12.
Artigo em Inglês | MEDLINE | ID: mdl-27835055

RESUMO

Restrictive strabismus resulting from the presence of an accessory extraocular muscle has rarely been reported in the literature. Most articles written on this topic are isolated case reports. The purpose of this paper is to describe a series of 7 similar patients presenting with atypical restrictive strabismus associated with enophthalmos in the affected eye, which was found to be caused by an accessory extraocular muscle attached to the posterior globe near the optic nerve. The medical records of 7 patients who shared these clinical characteristics were retrospectively analyzed. Orbital imaging was obtained in the 7 cases, which were compared. Three of the patients were females and four were males. The left eye was affected in all 4 males and the right eye was affected in the 3 females. The 7 patients presented with the following clinical characteristics: enophthalmos, restriction to eye movements in most fields of gaze, and presence of an anomalous orbital structure that was interpreted on magnetic resonance imaging (MRI) to be an accessory extraocular muscle inserting onto the posterior surface of the globe in the affected eye. The fellow eye was normal in all cases. Five of the 7 patients underwent surgical correction with partial improvement in only one patient. The presence of an accessory extraocular muscle should be included in the differential diagnosis of patients with atypical restrictive strabismus. Orbital computed tomography or MRI are essential for correct diagnosis in these cases.


Assuntos
Anormalidades do Olho/complicações , Músculos Oculomotores/anormalidades , Estrabismo/etiologia , Adolescente , Criança , Pré-Escolar , Diagnóstico Diferencial , Enoftalmia/diagnóstico , Enoftalmia/etiologia , Anormalidades do Olho/diagnóstico por imagem , Movimentos Oculares/fisiologia , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Músculos Oculomotores/diagnóstico por imagem , Estudos Retrospectivos , Estrabismo/diagnóstico , Tomografia Computadorizada por Raios X , Adulto Jovem
8.
Artigo em Inglês | MEDLINE | ID: mdl-25437842

RESUMO

In this work, hybrid structured Bi-Au-ZnO composite was prepared by precipitation-decomposition method. This method is mild, economical and efficient. Bi-Au-ZnO was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectrum (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL) and BET surface area measurements. Photocatalytic activity of Bi-Au-ZnO was evaluated by irradiating the Acid Red 18 (AR 18) dye solution under sun light. Heterostructured Bi-Au-ZnO photocatalyst showed higher photocatalytic activity than those of individual Bi-ZnO, Au-ZnO, bare ZnO, and TiO2-P25 at pH 11. The effects of operational parameters such as the amount of catalyst dosage, dye concentration, initial pH on photo mineralization of AR 18 dye have been analyzed. The mineralization of AR 18 has been confirmed by chemical oxygen demand (COD) measurements. A possible mechanism is proposed for the degradation of AR 18 under sun light. Finally, Bi-Au-ZnO heterojunction photocatalyst was more stable and could be easily recycled several times opening a new avenue for potential industrial applications.


Assuntos
Bismuto/química , Corantes/isolamento & purificação , Ouro/química , Fotólise , Rodaminas/isolamento & purificação , Catálise , Luz Solar , Óxido de Zinco/química
9.
Transplant Proc ; 46(10): 3598-602, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25498096

RESUMO

BACKGROUND: Ex vivo lung perfusion (EVLP) identifies viability for marginal organs but complicates and lengthens lung transplantation surgery. Preliminary evidence supports equivalency for EVLP-assisted versus traditional (non-EVLP) procedures regarding graft function, postoperative course, mortality, and survival. However, acute kidney injury (AKI), a common serious complication of lung transplantation, has not been assessed. We tested the hypothesis that EVLP-assisted and non-EVLP lung transplantations are associated with different AKI rates. METHODS: Demographic, procedural, and renal data were gathered for 13 EVLP-viable lung transplantations and a non-EVLP group matched 4:1 for single versus double, pulmonary disease, and age. AKI was defined by AKI Network (AKIN) criteria and peak creatinine rise relative to baseline (Δ%Cr) during the 1st 10 postoperative days. Chi-square was performed for AKIN and 2-tailed t test for %ΔCr. RESULTS: Patient and procedural characteristics were similar between the groups. One non-EVLP patient required postoperative dialysis. AKI rates were also similar, as assessed by both AKIN (EVLP 7/13 (54%) vs non-EVLP 32/52 (62%); P = .61) and %ΔCr (EVLP 91 ± 81% vs non-EVLP 72 ± 62%; P = .63). CONCLUSIONS: We did not observe different AKI rates between EVLP-assisted and traditional lung transplant procedures. Although 1 non-EVLP patient required dialysis, AKI rates were otherwise similar. These findings further support EVLP as a strategy to expand the organ pool and reduce concerns for high-renal risk recipients. The small sample size and retrospective design are limitations. However, our sample size is similar to other reports, and it is the first to analyze AKI after EVLP-assisted lung transplantation. Larger multicenter prospective studies are needed.


Assuntos
Lesão Renal Aguda/etiologia , Transplante de Pulmão/métodos , Preservação de Órgãos/métodos , Perfusão/efeitos adversos , Lesão Renal Aguda/epidemiologia , Circulação Extracorpórea/métodos , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , North Carolina/epidemiologia , Estudos Retrospectivos , Medição de Risco , Taxa de Sobrevida/tendências , Obtenção de Tecidos e Órgãos/métodos
10.
Science ; 345(6196): 491, 2014 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-25082671
11.
J Nanosci Nanotechnol ; 14(2): 1898-910, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24749464

RESUMO

This article reports on recent developments in heterogeneous AOP processes such as photocatalysis, Fenton-like process and catalytic ozonation. The principle, mechanism, and influence of experimental conditions on the degradation of pollutants in heterogeneous catalytic ozonation and the photocatalytic process were discussed. Introducing solid catalysts substantially increased the efficiency of the ozonation process by producing hydroxyl radicals in the degradation process. The different types of catalyst, catalyst dosage, solution pH, ozone flow rate, water matrix and catalytic reusability and stability are reported on here. The list of various semiconductor materials used as photocatalysts, their light absorption properties, various light sources and surface properties such as surface area, pore size and pore volume as a factor in the photocatalytic degradation of various pollutants are discussed. The review article also discussed the pollutants degraded using these three processes.


Assuntos
Poluentes Ambientais/química , Poluentes Ambientais/isolamento & purificação , Recuperação e Remediação Ambiental/métodos , Nanopartículas/química , Nanotecnologia/métodos , Fotoquímica/métodos , Catálise
12.
Indian J Med Res ; 138(3): 383-91, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24135188

RESUMO

Food and nutrition security are intimately interconnected, since only a food based approach can help in overcoming malnutrition in an economically and socially sustainable manner. Food production provides the base for food security as it is a key determinant of food availability. This paper deals with different aspects of ensuring high productivity and production without associated ecological harm for ensuring adequate food availability. By mainstreaming ecological considerations in technology development and dissemination, we can enter an era of evergreen revolution and sustainable food and nutrition security. Public policy support is crucial for enabling this.


Assuntos
Abastecimento de Alimentos , Agricultura , Humanos , Índia/epidemiologia
13.
Artigo em Inglês | MEDLINE | ID: mdl-23832224

RESUMO

Solar active WO3 loaded Ag-ZnO (WO3-Ag-ZnO) was successfully synthesized by precipitation-decomposition method. XPS reveals that the presence of metallic silver in the catalyst. The photocatalytic activity of WO3-Ag-ZnO was investigated for the degradation of Reactive Red 120 (RR 120) in aqueous solution using solar light. WO3-Ag-ZnO is found to be more efficient than Ag-ZnO, WO3-ZnO, Ag-WO3, commercial ZnO, prepared ZnO, Degussa TiO2-P25, pure WO3 and TiO2 (Merck) at pH 7 for the mineralization of RR 120. The effects of operational parameters such as the amount of photocatalyst, dye concentration, initial pH on photo mineralization of RR 120 have been analyzed. The mineralization of RR 120 has been confirmed by COD measurements. A dual mechanism has been proposed for efficient degradation of RR 120 dye with WO3-Ag-ZnO under solar light at neutral pH. This catalyst is found to be reusable.


Assuntos
Fotólise/efeitos da radiação , Luz Solar , Triazinas/efeitos da radiação , Análise da Demanda Biológica de Oxigênio , Catálise/efeitos da radiação , Concentração de Íons de Hidrogênio/efeitos da radiação , Espectroscopia Fotoeletrônica , Soluções , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Triazinas/química
14.
Artigo em Inglês | MEDLINE | ID: mdl-23318775

RESUMO

The Ag(2)S loaded ZnO (Ag(2)S-ZnO) was successfully synthesized by precipitation of zinc oxalate and Ag(2)S and calcination of the mixed precipitate at 400 °C for 12 h. The catalyst was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) images, energy dispersive spectra (EDS), diffuse reflectance spectra (DRS) photoluminescence spectra (PL) and BET surface area measurements. The photocatalytic activity of Ag(2)S-ZnO was investigated for the degradation of Acid Black (AB 1) in aqueous solution using UV light. Ag(2)S-ZnO is found to be more efficient than commercial ZnO, prepared ZnO and TiO(2)-P25 at pH 9 for the mineralization of Acid Black 1. The effects of operational parameters such as the amount of photocatalyst, dye concentration, initial pH on photo mineralization have been analyzed. Mechanism of degradation by Ag(2)S-ZnO is proposed. The mineralization of Acid Black 1 has also been confirmed by COD measurements. The catalyst is found to be reusable.


Assuntos
Negro de Amido/química , Corantes/química , Compostos de Prata/química , Óxido de Zinco/química , Negro de Amido/isolamento & purificação , Catálise , Precipitação Química , Corantes/isolamento & purificação , Fotólise , Raios Ultravioleta
15.
Langmuir ; 29(3): 939-49, 2013 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-23234536

RESUMO

The different wt % of Zr-codoped Ag-ZnO catalysts were prepared by the simple precipitation-thermal decomposition method and used for degradation of anionic azo dye Reactive Red 120 (RR 120) under natural sunlight. Highly efficient 4 wt % of Zr-codoped Ag-ZnO was characterized by X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM) images, field emission scanning electron microscope (FE-SEM) images, energy-dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), cyclic voltammetry (CV), X-ray photoelectron spectroscopy (XPS), and BET surface area measurements. Metal codopants increase the absorbance of ZnO to the entire visible region. XRD and XPS reveal that Ag is in the form of Ag(0) and Zr in the form of Zr(4+). The photocatalytic activity of 4 wt % Zr-codoped Ag-ZnO was compared with other single-metal-doped, undoped, and commercial catalysts. The quantum yields of all processes were determined and analyzed. Zr-Ag-ZnO was found to be more efficient than Ag-ZnO, Zr-ZnO, commercial ZnO, prepared ZnO, TiO(2)-P25, and TiO(2) at neutral pH for mineralization of RR 120 under solar light. To the best of our knowledge, this is the first report on the synthesis of Zr-codoped Ag-ZnO and its use in the degradation of RR 120 dye under natural sunlight illuminatioin. The influences of operational parameters such as the amount of photocatalyst, dye concentration, and initial pH on photomineralization of RR 120 have been analyzed. Mineralization of RR 120 has been confirmed by chemical oxygen demand (COD) measurements. A dual mechanism has been proposed for the higher efficiency of Zr-Ag-ZnO at neutral pH under solar light. This catalyst is found to be reusable.


Assuntos
Prata/química , Triazinas/química , Óxido de Zinco/química , Zircônio/química , Catálise , Oxigênio/análise , Tamanho da Partícula , Processos Fotoquímicos , Propriedades de Superfície , Raios Ultravioleta
16.
Front Genet ; 3: 282, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23227031
18.
Artigo em Inglês | MEDLINE | ID: mdl-23063859

RESUMO

The photocatalytic activity of AgBr-ZnO was investigated for the degradation of Acid Violet 7 (AV 7) in aqueous solution using UV-A light. AgBr-ZnO is found to be more efficient than commercial ZnO and prepared ZnO at pH 12 for the mineralization of AV 7. The effects of operational parameters such as the amount of photocatalyst, dye concentration, initial pH on photo mineralization have been analyzed. Expect oxone, other oxidants decrease the degradation efficiency. Addition of metal ions and anions decrease the degradation efficiency of AgBr-ZnO significantly. The mineralization of AV 7 has also been confirmed by COD measurements. The mechanism of degradation by AgBr-ZnO is proposed to explain its higher activity under UV light. The catalyst is found to be reusable.


Assuntos
Compostos Azo/química , Brometos/química , Corantes/química , Naftalenossulfonatos/química , Fotólise , Compostos de Prata/química , Óxido de Zinco/química , Catálise , Concentração de Íons de Hidrogênio , Oxidantes/química , Raios Ultravioleta
19.
ISRN Org Chem ; 2012: 595868, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-24052847

RESUMO

A new BiCl3-loaded montmorillonite K10 catalyst has been prepared by solid dispersion method and was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and cyclic voltammetry (CV) measurements. BiCl3 loaded K10 (BiCl3-K10) has been used as solid acid catalyst for the synthesis of azine derivatives from benzophenone hydrazone and ketones/aldehydes by simple physical grinding. This BiCl3-K10 gives an excellent yield with short reaction time and is an inexpensive, easily recyclable catalyst for this reaction.

20.
Spectrochim Acta A Mol Biomol Spectrosc ; 81(1): 739-44, 2011 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-21788154

RESUMO

The photocatalytic degradation of a genotoxic azo dye Acid Violet 7 (AV 7) using ZnO as a photocatalyst in aqueous solution has been investigated under UV irradiation. The degradation is higher with UV/ZnO process than with UV/TiO(2)-P25 process at pH 9. The effects of different parameters such as pH of the solution, amount of catalyst, initial dye concentration and the influence of cations, anions and oxidants on photodegradation of AV 7 were analyzed. Addition of oxidants except H(2)O(2) has no significant effect on degradation. The degradation of AV 7 follows pseudo-first order kinetics according to the Langmuir-Hinshelwood model. The degradation of AV 7 has also been confirmed by COD and CV measurements.


Assuntos
Compostos Azo/química , Naftalenossulfonatos/química , Fotólise , Óxido de Zinco/farmacologia , Compostos Azo/efeitos da radiação , Catálise , Corantes/química , Corantes/efeitos da radiação , Modelos Biológicos , Mutagênicos/química , Mutagênicos/efeitos da radiação , Naftalenossulfonatos/efeitos da radiação , Fotoquímica , Fotólise/efeitos dos fármacos , Suspensões/química , Suspensões/farmacologia , Raios Ultravioleta , Água/química , Água/farmacologia , Óxido de Zinco/química
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