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1.
Nanomedicine (Lond) ; 16(8): 657-671, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33754834

RESUMEN

Aim: To investigate the effect of ultrasound during the synthesis of ZnO nanoparticles (NPs) on their anticancer activity. Materials & methods: ZnO NPs were synthesized in the presence and absence of ultrasonic irradiation. Biological tests were performed on human osteosarcoma cancer cells (Saos-2). Results: The sono-synthesized sample indicated higher cytotoxicity than the conventional one. (IC50 = 16.48 ± 0.41 µg/ml for sonochemical ZnO; 26.96 ± 0.33 µg/ml for conventional ZnO). Both sonochemical and conventional samples acted like antioxidants and reduced intracellular reactive oxygen species level. This reduction was more significant in cells treated with the sono-synthesized sample. The sono-synthesized ZnO NPs showed more tumor selectivity than the conventional sample. Conclusion: Sono-synthesis of ZnO NPs by a bath sonicator could improve their anticancer activity.


Asunto(s)
Neoplasias Óseas , Nanopartículas del Metal , Osteosarcoma , Neoplasias Óseas/tratamiento farmacológico , Supervivencia Celular , Humanos , Osteosarcoma/tratamiento farmacológico , Especies Reactivas de Oxígeno , Óxido de Zinc
2.
Artículo en Inglés | MEDLINE | ID: mdl-35026978

RESUMEN

BACKGROUND AND AIMS: Due to the increasing prevalence of obesity and related disorders, there is an urgent need to examine the relationship between diet quality and public health. The Alternative Healthy Eating Index (AHEI) is one of the indices that is used to assess diet quality. Therefore, we investigated the relationship between AHEI and anthropometric measurements and blood pressure. METHODS: In this cross-sectional study, 127 male and female hospital employees were examined. The AHEI was calculated by a 168 items Food Frequency Questionnaire. Body weight, height, Body Mass Index (BMI), Waist Circumference (WC), Waist-to-Hip Ratio (WHR) and blood pressure were measured by skilled nutritionists. Physical activity level was also obtained by International Physical Activity Questionnaire (IPAQ). RESULTS: The mean total AHEI score in participants was reported as 47.1±6.9 (min=31.9, max=60.3). The mean differences of total AHEI score across the obese/non-obese employees were not statistically significant (P>0.05). Furthermore, there was no significant correlation between total AHEI score and BMI (r=0.019), WC (r=0.022), WHR (r=-0.102), systolic (r=-0.133) and diastolic blood pressure (r=-0.040) (P>0.05). The score of nuts and soybeans was inversely related to the WHR (P=0.008) and systolic blood pressure (P=0.030). Cereal fiber score had a negative relationship with BMI (P=0.02), WC (P=0.03), WHR (P=0.004) and systolic (P<0.001) and diastolic blood pressure (P=0.012). CONCLUSION: Consumption of nuts and soybeans -one serving per day- can be associated with WHR and systolic blood pressure reduction. More studies with a larger scale are needed to examine diet quality.


Asunto(s)
Dieta Saludable , Obesidad Abdominal , Presión Sanguínea , Índice de Masa Corporal , Estudios Transversales , Femenino , Hospitales , Humanos , Irán/epidemiología , Masculino , Obesidad/diagnóstico , Obesidad/epidemiología , Obesidad Abdominal/diagnóstico , Obesidad Abdominal/epidemiología , Factores de Riesgo , Circunferencia de la Cintura
3.
Ultrason Sonochem ; 67: 105145, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32371348

RESUMEN

The use of crystal facets of photocatalysts is well known as a promising strategy for the design of new photocatalysts with interesting physicochemical features for energy production applications. In this work, Bi2MoO6 thin films were synthesized by two methods, electrodeposition and sonoelectrodeposition. Preferential growth orientation depended on synthesis method. Results suggested that sonoelectrodeposition led to dominate the crystal facet {1 0 0} growth with self-assembled nanoplate morphologies while growth orientation in the {0 1 0} facet was dominant in electrodeposition in the absence of ultrasonic waves. As a highlight result, the {1 0 0} facet shows a smaller band gap, higher photocatalytic water splitting than the {0 1 0} facet. Efficient separation of charge pairs and long life time of photogenerated electrons was observed to be intrinsic features of the {1 0 0} facets. The higher charge transfer was confirmed by a higher photocurrent from linear sweep voltammetry and a smaller Nyquist radius arc. Ultrasound plays a key role in growth orientation and led to a production of homogeneous films with nanoplates which self-assembled together to form a flower-like structure. While in the absence of ultrasound the film has coral-like structure. Highly stable sonoelectrodeposited films exhibited incident photon-to-electron conversion efficiency (IPCE) of 22.4% at the specific wavelength of 500 nm. The sonoelectrodeposition method could act as a promising method for forming new films with specific crystal facet selection and developing as highly efficient photoanodes for PEC water splitting.

4.
Ultrason Sonochem ; 62: 104867, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31806551

RESUMEN

For the first time, Bi2MoO6 nanofilms were successfully synthesized by simultaneous pulse sonication-pulse electrodeposition (PS-PED) on the stainless steel mesh surface. Bismuth molybdate films were formed under various combinations of electrodeposition and sonication (sono-electrodeposition) in continuous and pulse modes. Porous Bi2MoO6 films synthesized by PS-PED method and showed the highest efficiency in photocatalytic degradation in comparison with other films. Bi2MoO6 film obtained from PS-PED had a thickness of 13.78 nm while, the thickness for the electrodeposition method was 39.52 nm. The high photocatalytic efficiency is attributed to the high surface roughness and low thickness of film synthesized by PS-PED method. Indeed, ultrasound played a key role in the synthesis of films with high surface roughness. On the other hand, shock waves and micro-jets could be dissolved diffusion problems and reduced the dendrite like structures in deposition process. Simultaneous application of pulse modes for both combined methods led to more growth of crystallographic planes. This is due to reaction of ions on the surface in interval relaxation times and produce more nuclei for growth. In order to obtain a high efficiency, response surface methodology was used for optimization of effective variable parameters (ton, toff and sonication amplitude) in film preparation.


Asunto(s)
Antiinflamatorios no Esteroideos/química , Bismuto/química , Diclofenaco/química , Galvanoplastia/métodos , Molibdeno/química , Nanoestructuras , Sonicación , Acero Inoxidable/química , Contaminantes Químicos del Agua/química , Catálisis , Procesos Fotoquímicos , Propiedades de Superficie
5.
J Hazard Mater ; 384: 121300, 2020 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-31590084

RESUMEN

In this work, for the first time, bismuth sulfide (Bi2S3) film formed on the stainless steel mesh surface as a suitable substrate. Different films were synthesized by various combinations of the two methods (sonochemistry and electrochemistry) in continuous and pulse modes. The Bi2S3 films characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and Atomic Force Microscope (AFM). To reach the best film for photocatalytic reduction of Cr (VI), different films were deposited on the substrate by changing three independent variables including pulse times (ton, toff) and sonication amplitude. Response Surface Methodology (RSM) applied for optimization of independent variables by using Central Composite Design (CCD). Here, the films prepared by sono-electrodeposition in pulse modes led to high photocatalytic efficiency in comparison with other films. The results confirmed that ultrasound affected the morphology of film due to the production of cavitation, micro jets and acoustic streaming. On the other hand, ultrasound decreased double layer thickness and dissolved diffusion problems. Sono-electrodeposition in pulse modes produced films with pumice and fractal like structures. The high photocatalytic activity attributed to special morphologies that have key roles in separation of hole/electron pairs and light multi-scattering.

6.
Mater Sci Eng C Mater Biol Appl ; 101: 27-41, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31029320

RESUMEN

In the present study, the aim was to develop a magneto-responsive nanocomposite for application in drug delivery by the integration of magnetic nanoparticles into an inorganic architecture, hydroxyapatite. The magnetic mesoporous hydroxyapatite nanocomposites, MMHAPs, were synthesized using a template-free method and fully characterized by XRD, FT-IR, TEM, FE-SEM, VSM, ICP, BET, and UV-Vis spectroscopy. MMHAPs exhibited a rod-like shape with a structure of large mesopores and high surface area. A sample of the nanocomposites with well-defined properties, MMHAP(2), was selected as a carrier for delivery of chemotherapy drug, doxorubicin (Dox). Then, it was coated with polyethylene glycol (P) and folic acid (F), providing aqueous stability and tumor targeting, respectively. The evaluation of drug release profile revealed that the release of drug occurs in a time-staggered manner under low pH conditions, which simulate the internal condition of lysosome. More important, a significant drug release was observed under a static magnetic field (SMF), displaying a magnetically triggered release. According to the toxicity assessment, MMHAP(2) did not show any noticeable toxic effect against the tumor cells (Saos-2) and normal cells (HEK-293) up to 100 µg ml-1 in the presence or absence of SMF. In contrast, the drug-loaded nanocomposite, F.P.D@MMHAP(2), possesses high antitumor efficacy particularly in the presence of SMF. Moreover, it was found that the cellular internalization of F.P.D@MMHAP(2) could be increased by SMF, providing therapeutic efficiency enhancement. The high cytotoxic effect of F.P.D@MMHAP(2) with the help of SMF caused apoptosis in the tumor cells, which was preceded by a disturbance in the intracellular redox state and then caspase activation. Based on the data obtained, F.P.D@MMHAP(2) is a pH- and magneto-responsive platform opening up a new perspective in terms of its exploitation in cancer therapy.


Asunto(s)
Durapatita/química , Nanopartículas de Magnetita/química , Terapia Molecular Dirigida , Nanocompuestos/química , Adsorción , Muerte Celular/efectos de los fármacos , Línea Celular Tumoral , Terapia Combinada , Liberación de Fármacos , Dispersión Dinámica de Luz , Células HEK293 , Humanos , Concentración de Iones de Hidrógeno , Concentración 50 Inhibidora , Cinética , Magnetometría , Nanocompuestos/ultraestructura , Tamaño de la Partícula , Polietilenglicoles/química , Porosidad , Espectroscopía Infrarroja por Transformada de Fourier , Electricidad Estática , Propiedades de Superficie , Difracción de Rayos X
7.
Ultrason Sonochem ; 51: 1-11, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30514478

RESUMEN

In the present work, an ultrasound-assisted hydrothermal method was applied as a new approach for the synthesis of Bi2WO6 nanostructures. In sonication, a cup horn system as an indirect high intensity sonicator was used. To determine the influence of ultrasonic waves on the morphology, Bi2WO6 was also synthesized using the hydrothermal method. The conventional and sonochemical products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), Fourier transform infrared (FTIR), Raman, photoluminescence (PL), and UV-Vis (UV-Vis) spectroscopies. The XRD patterns confirmed that the sonosynthesized sample has higher crystallinity than the conventional one. The results also showed that ultrasound decreased the particle size and improved the size distribution. In comparison with the hydrothermal sample, the flower like structures formed under sonication have many hollow sites, resulting in higher harvesting and scattering of visible light. The efficiency of resulting nanoparticles in degradation of a binary mixture (RhB/MB) as pollutant was evaluated by photocatalytic, sonocatalytic, and sonophotocatalytic processes. The sono-synthesized sample removed the pollutants four times faster than the hydrothermal sample in sonophocatalytic process. Besides, determining factors including pH, pollutant concentration, temperature, and ultrasound amplitude were optimized in the sonophotocatalytic process.

8.
Ultrason Sonochem ; 44: 1-13, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29680590

RESUMEN

In this research, a facile, one step and eco-friendly sonochemical rout was utilized to the synthesis of a new nanocomposite by Ag nanoparticle anchored on reduced graphene oxide (rGO-Ag-U). Sonication was carried out by using low frequency ultrasound (20 kHz) under ambient condition. In this way, graphene oxide and Ag+ ions simultaneously reduced by polyol without using any additional reactants or capping agents. The polyol serves as both solvent and low toxic reducing agent. To achieve the best synthesis condition of rGO-Ag-U nanocomposite, the effects of irradiation time, ultrasonic amplitude and reaction temperature were investigated. In comparison, the synthesis of rGO-Ag was also carried out via reflux as a classical method (rGO-Ag-C). It was found that ultrasonic irradiation for 10 min at 70% amplitude was sufficient for the synthesis of rGO-Ag-U. Several analytical techniques were used to characterize the resulting nanocomposites such as UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The UV-Vis spectra show a shift of GO band to a higher wavelength which is due to the reduction of sp3 sites. The results of TEM also confirm the smaller Ag nanoparticle (about 18 nm) which uniformly decorated on rGO nanosheets by sonochemical method than classical method. The experimental data suggest that among the synthesized nanocomposites, rGO-Ag-U exhibited better catalytic activity (kapp = 1.18 min-1) towards the reduction of 4-Nitrophenol to 4-Aminophenol in the presence of sodium borohydride (NaBH4).

9.
Ultrason Sonochem ; 44: 380-389, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29680624

RESUMEN

Considering the current interest in the preparation of modified surfaces with fixed nanostructures, in this research, the hot water treatment was chosen as a simple and efficient procedure for the direct growth of ZnO nanostructures (ZnO NSs) on the metallic surface. To improve the method and reduce the cost of experiments, the commercial galvanized steel (steel containing a thin layer of zinc) was used as the base substrate. The use of the galvanized steel as an inexpensive and available metal surface has advantages compared to the pure Zn foil (used in other researches). In addition, in the present work, the effective pretreatment of the base substrate surface by applying the chemical etching under the low intensity ultrasonic irradiation facilitated the reaction progress (Zn → ZnO) in a shorter time and relatively low temperature in comparison to many reports. To find the effect of acoustic energy on the final ZnO morphology, the hot water treatment was carried out under conventional and sonochemical conditions. Finally, as a practical application, resulting surfaces were coated with electroless Ni-P deposits and the effect of as-grown ZnO NSs (as the sublayer) on improvement in the corrosion protection of binary Ni-P deposits was evaluated by the electrochemical method.

10.
Ultrason Sonochem ; 41: 492-502, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29137780

RESUMEN

The several types of sonication methods were applied to access the different morphologies of ZnO nanostructures on the surface of mild steel. To achieve this goal, a sonictor equipped with the probe extender was used as a high intensity ultrasonic apparatus for direct sonication. Furthermore, an ultrasonic bath (low intensity) and a cup-horn system (high intensity) were applied for indirect sonication. To find the effect of the acoustic waves on the ZnO morphology, the micrographs of obtained surfaces were compared to the sample prepared by the conventional method using scanning electron microscopy (SEM). In this work, the beneficial effects of sonication were subjected on the breaking down the agglomerates to smaller size particles, metal surface activation, and on the facile approach to nanostructures synthesis. The influence of the resulting ZnO structures over the corrosion protection of the electroless Ni-P alloy coatings was evaluated by the potentiodynamic polarization technique (Tafel extrapolation).

11.
Ultrason Sonochem ; 38: 234-245, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28633823

RESUMEN

C-N-S-tri doped TiO2 anatase phase was synthesized using a facile, effective and novel sonochemical method at low frequency (20kHz) and at room temperature. Titanium butoxide as the titanium precursor and thiourea as the dopant source were used in the synthesis of the photo-catalyst. The effects of important parameters such as thiourea/Ti molar ratio, ultrasound intensity, sonication time and temperature were studied on the synthesis of tri-doped TiO2. The XPS results confirmed the presence of N, S, and C in the photo-catalyst. The photo-catalytic efficiency of the synthesized catalyst was studied toward the removal of Diclofenac as a model pharmaceutical organic pollutant. The results confirmed that the photo-catalyst synthesized with narrower band gap energy, shorter sonication time and higher ultrasound intensity leads to a rapid removal of Diclofenac. The effect of operational variables on the photo-catalytic activity of C-N-S tri doped TiO2 nanoparticles was studied and optimized using the Taguchi method as a statistical technique. Additionally, the degradation process followed the pseudo-first-order kinetics model and the highest apparent rate constant of 0.0632min-1 achieved in 90min. Chemical oxygen demand (COD) analysis confirmed that the mineralization took place completely (100%) under the optimized conditions in 180min. Different scavengers were applied during the degradation process and active species such as OH and O2- had key roles in the photo-catalytic process.

12.
J Colloid Interface Sci ; 463: 37-45, 2016 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-26513735

RESUMEN

Fabrication of suitable roughness is a fundamental step for acquiring superhydrophobic surfaces. For this purpose, a deposition of ZnO nanoparticles on Al surface was carried out by simple immersion and ultrasound approaches. Then, surface energy reduction was performed using stearic acid (STA) ethanol solution for both methods. The results demonstrated that ultrasound would lead to more stable superhydrophobic Al surfaces (STA-ZnO-Al-U) in comparison with simple immersion method (STA-ZnO-Al-I). Besides, etching in HCl solution in another sample was carried out before ZnO deposition for acquiring more mechanically stable superhydrophobic surface. The potentiodynamic measurements demonstrate that etching in HCl solution under ultrasound leads to superhydrophobic surface (STA-ZnO-Al(E)-U). This sample shows remarkable decrease in corrosion current density (icorr) and long-term stability improvement versus immersion in NaCl solution (3.5%) in comparison with the sample prepared without etching (STA-ZnO-Al-U). Scanning electron micrograph (SEM) and energy-dispersive X-ray spectroscopy (EDX) confirmed a more condense and further particle deposition on Al substrate when ultrasound was applied in the system. The crystallite evaluation of deposited ZnO nanoparticles was carried out using X-ray diffractometer (XRD). Finally, for STA grafting verification on Al surface, Fourier transform infrared in conjunction with attenuated total reflection (FTIR-ATR) was used as a proper technique.

13.
J Colloid Interface Sci ; 464: 291-300, 2016 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-26658358

RESUMEN

High agglomeration of the nanoparticles and low volume fraction of nanosized inert particles within the nanocomposite thin films are found as the practical problems. In our previous work, silica coated ZnO nanoparticles (ZnO@SiO2 NPs) were synthesized to prevent dissolution of the ZnO nanoparticles (ZnO NPs) in the electrolytic Ni bath. The high agglomeration of these core-shell particles led to an unequal particle distribution in the deposit matrix. In this work, we aimed to prepare a highly homogeneous nanocomposite coating by stabilizing the nanoparticles in the medium. Adding the buffering agents, including phosphoric and boric acids to the medium, disclosed their new aspect of these inorganic acids in the prevention of particle agglomeration. The corrosion study of the resulting well-dispersed Ni-P/Zn@SiO2 nanocomposite coating confirmed a significant increase in anticorrosion performance. This increase was about 2.3 times compared to the previously prepared coating. Moreover, the probable mechanisms of phosphoric and boric acids in particle stability through the steric or/and electrostatic repulsion at the interfaces between the colloidal nanoparticles (ZnO@SiO2 NPs) and the electrolyte solution were investigated in detail.

14.
Clin Nutr Res ; 4(4): 225-34, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26566517

RESUMEN

Recent studies suggest that inclusion of soy product in the diet may have favorable effects on relief of cardiovascular diseases (CVDs) and risk factors. These effects might be associated with the presence of specific polymorphism in gene. The aim of this study was to examine the effects of consumption of soy flour fortified bread on cardiovascular risk factors in overweight and obese women according to APOE genotype. In a randomized cross-over clinical trial 30 overweight and obese women received a mild weight loss diet and assigned to a regular diet and a soy bread diet, each for 6 weeks and a washout period for 20 days. Subjects in the soy bread diet were asked to replace 120 grams of their daily usual bread intake with equal amount of soy bread. No significant effects of soy bread on serum lipid, systolic blood pressure and anthropometric indices were observed compared to the regular diet (p > 0.05). For diastolic blood pressure (DBP), comparison of mean differences between two groups showed a marginally significant effect of soy bread (p = 0.06). Compared to regular diet, soy bread had a significant effect on DBP in E2 genotype group (ε2/ε2) (p = 0.03). Having ε2 allele may influences responses of CVD risk factor to soy bread consumption. However more nutrigenetic studies are required.

15.
Ultrason Sonochem ; 27: 466-473, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26186868

RESUMEN

In the present study, the sono-synthesis of ZnO nanoparticles (NPs) was performed by simple, low-cost, and the environmentally friendly method. The synthesis of zinc oxide as an antibacterial agent was performed by an ultrasonic bath (low intensity) for the indirect sonication and a horn system (high intensity) for the direct sonication. The samples synthesized by these two kinds of sonication were compared with each other. Crystallographic structures and the morphologies of the resultant powders were determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD patterns showed that both ZnO samples were crystallized in their pure phase. The TEM images confirmed that the morphologies of the products were completely different from each other. Based on the obtained analysis, the probable growth mechanisms were proposed for crystallization of both samples. The antibacterial activity of the synthesized species was evaluated by the colony count method against Escherichia coli O157:H7. Moreover, the optical behavior of the samples was studied by UV-vis spectroscopy and the variation of the ZnO band gap was compared.


Asunto(s)
Antibacterianos/química , Antibacterianos/farmacología , Nanopartículas/química , Fenómenos Ópticos , Sonicación , Óxido de Zinc/química , Óxido de Zinc/farmacología , Escherichia coli/efectos de los fármacos , Pruebas de Sensibilidad Microbiana
16.
J Colloid Interface Sci ; 455: 110-6, 2015 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-26057943

RESUMEN

The pure phase of the ZnO nanoparticles (NPs) as anticorrosive pigments was synthesized by the sonication method. The surfaces of the sono-synthesized nanoparticles were covered with the protective silica layer. The durability of the coated and uncoated ZnO NPs in the used electrolytic Ni bath was determined by flame atomic absorption spectrometry. In the present research the multicomponent Ni bath as the complex medium was replaced by the simple one. The used nickel-plating bath was just composed of the Ni salts (as the sources of the Ni(2+) ions) to better clarify the influence of the presence of the ZnO@SiO2 core-shell NPs on the stability of the medium. The effect of ZnO@SiO2 NPs incorporation on the morphology of the solid electroformed Ni deposit was studied by scanning electron microscopy (SEM). Furthermore, the influence of the co-deposited particles in the Ni matrix on the corrosion resistance of the Ni coating was evaluated by the electrochemical methods including linear polarization resistance (LPR) and Tafel extrapolation.

17.
J Mol Graph Model ; 59: 21-30, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25889015

RESUMEN

Despite extensive studies of the amino-functionalized silica surfaces, a comprehensive investigation of the effects of configuration and hydrolysis of 3-aminopropyltriethoxysilan (APTES) molecules attached on silica has not been studied yet. Therefore, the methods of quantum mechanics were used for the study of configuration and hydrolysis forms of APTES molecules attached on the surface. For this purpose, five different categories based on the number of hydrolyzed ethoxy groups including 16 configurations were designed and analyzed by the density functional theory (DFT) method. The steric hindrance as an effective factor on the stability order was extracted from structural analysis. Other impressive parameters such as the effects of hydrogen bond and electron delocalization energy were obtained by using the atoms in molecules (AIM) and natural bond orbitals (NBO) theories. Consequently, it was found that the stability of configurations was attributed to steric effects, hydrogen bond numbers and electron delocalization energy. The maximum stability was achieved when at least two of these parameters cooperate with each other.


Asunto(s)
Dióxido de Silicio/química , Electrones , Enlace de Hidrógeno , Hidrólisis , Modelos Moleculares , Propilaminas , Teoría Cuántica , Silanos/química , Electricidad Estática
18.
Environ Sci Pollut Res Int ; 22(14): 10733-43, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25752639

RESUMEN

Rapid development of nanotechnology in recent years has raised concerns about nanoparticle (NPs) release into the environment and its adverse effects on living organisms. The present study is the first comprehensive report on the anatomical and ultrastructural changes of a variety of cells after long-term exposure of plant to NPs or bulk material particles (BPs). Light and electron microscopy revealed some anatomical and ultrastructural modifications of the different types of cell in the root and leaf, induced by both types of treatment. Zinc oxide (ZnO) BPs-induced modifications were surprisingly more than those induced by ZnO NPs. The modifications induced by ZnO BPs or ZnO NPs were almost similar to those induced by excess Zn. Zn content of the root and leaf of both ZnO NPs- and ZnO BPs-treated plants was severely increased, where the increase was greater in the plants treated with ZnO BPs. Overall, these results indicate that the modifications induced by ZnO particles can be attributed, at least partly, to the Zn(2+) dissolution by ZnO particles rather than their absorption by root and their subsequent effects.


Asunto(s)
Brassica napus/ultraestructura , Brassica rapa/ultraestructura , Nanopartículas/toxicidad , Contaminantes del Suelo/toxicidad , Óxido de Zinc/toxicidad , Brassica napus/efectos de los fármacos , Brassica napus/crecimiento & desarrollo , Brassica napus/metabolismo , Brassica rapa/efectos de los fármacos , Brassica rapa/crecimiento & desarrollo , Brassica rapa/metabolismo , Nanopartículas/química , Tamaño de la Partícula , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/metabolismo , Hojas de la Planta/ultraestructura , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/metabolismo , Raíces de Plantas/ultraestructura , Contaminantes del Suelo/química , Contaminantes del Suelo/metabolismo , Óxido de Zinc/química , Óxido de Zinc/metabolismo
19.
Ultrason Sonochem ; 20(6): 1419-27, 2013 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23618850

RESUMEN

La0.7Sr0.3MnO3 (LSMO) nanoparticles with a perovskite structure were prepared by a combination of ultrasound and co-precipitation method. The synthesized catalyst was characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy. The catalytic performance of the catalyst was evaluated for the degradation of 4-chlorophenol in the presence and in the absence of ultrasound. The degradation has been studied at different temperatures, pH, catalyst dosage, and initial concentration of 4-chlorophenol. The results have shown that the degradation efficiency was higher in the presence of ultrasound than its absence under the mild conditions. More than 88% decrease in the concentration and 85% decrease in the TOC for 4-chlorophenol could be achieved in a short time of sonication with respect to the conventional method. This behavior could be attributed to the cavitation process which followed by a high mass transfer on the catalyst with high surface area. These conditions led to facilitate the removal of pollutant from aqueous solution. The results also indicated that the catalyst without recalcination can be used successfully up to five consecutive cycles without any significant loss in activity in the presence and in the absence of ultrasound. In addition, the most important is the magnetic property of the nanoparticles which separated easily from aqueous solution by an external magnetic field.


Asunto(s)
Clorofenoles/química , Lantano/química , Compuestos de Manganeso/química , Nanoestructuras/química , Óxidos/química , Estroncio/química , Catálisis , Concentración de Iones de Hidrógeno , Fenómenos Magnéticos , Temperatura , Ultrasonido
20.
Ultrason Sonochem ; 19(5): 1070-8, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22365027

RESUMEN

A core-shell nanocomposite (CdS/TiO(2)) was synthesized at relatively low temperature (70°C) with small particle sizes (~11 nm). First, CdS nanoparticles were prepared by a combination of ultrasound and new micro-emulsion (O/W) without surfactant. Then the synthesized CdS was easily combined with TiO(2) under sonication. The formation of uniform surface layer of TiO(2) with depths of 0.75-1.1 nm on the CdS led to an increase of particle size. Ultrasonic irradiation can control the hydrolysis and condensation of titanium tetra-isopropoxide (TTIP) and the formation of TiO(2) shell around the CdS core. This technique avoids some of the problems that exist in conventional microemulsion synthesis such as the presence of different additives and calcinations. It was found that nanocomposite particles extend the optical absorption spectrum into the visible region in comparison with pure TiO(2) and pure CdS. In addition, a larger depth of TiO(2) led to a red-shift of the absorption band in nanocomposite. The characterization of nanocomposites has been studied by HRTEM, TEM, XRD, EDAX, BET and, UV-vis.

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