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1.
J Assoc Physicians India ; 72(3): 47-50, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38736117

RESUMEN

BACKGROUND: Gestational hypertension carries a high-risk for adverse maternal and fetal outcomes, and it can also develop into preeclampsia. A relative decrease in parasympathetic and increase in sympathetic activity has been seen in normal pregnancy which returns to baseline after delivery. The present study aimed to detect any abnormality in sympathetic neurofunction in gestational hypertension and to identify its possible association with the development of preeclampsia/eclampsia. METHODS: A prospective, observational study was carried out among gestational hypertensive patients between 24 and 26 weeks of gestation, who were sent to clinical pharmacology clinics for autonomic neurofunction testing, along with their 24-hour urinary protein testing reports. Preisometric handgrip (IHG) and post-IHG differences in diastolic blood pressure (DBP) were noted. The association between Δ DBP and the development of eclampsia/preeclampsia was probed. RESULTS: A total of 52 pregnancy-induced hypertension (PIH) participants, both multigravida (n = 15) and primigravida (n = 37) were included in one arm (PIH arm), and 52 matched (age and gravida) pregnant women, those do not have PIH included in another arm for comparative analysis. On comparing the PIH arm and normal arm, prehand grip DBP (p ≤ 0.0001), posthand grip DBP, and Δ DBP were significantly higher in the PIH arm. Correlation between Δ DBP and 24 hours' proteinuria was observed in the PIH arm, with a significant positive correlation. CONCLUSION: A high-rise in DBP post-IHG exercise is associated with gestational hypertensive mothers and this rise is strongly correlated with the development of preeclampsia and eclampsia, which suggests that addressing sympathetic hyperactivity could be a potential area to target therapeutics while managing gestational hypertension.


Asunto(s)
Eclampsia , Hipertensión Inducida en el Embarazo , Preeclampsia , Sistema Nervioso Simpático , Humanos , Embarazo , Femenino , Preeclampsia/fisiopatología , Preeclampsia/diagnóstico , Hipertensión Inducida en el Embarazo/fisiopatología , Adulto , Estudios Prospectivos , Sistema Nervioso Simpático/fisiopatología , Eclampsia/fisiopatología , Fuerza de la Mano/fisiología , Presión Sanguínea/fisiología , Adulto Joven
2.
Dalton Trans ; 52(42): 15360-15364, 2023 Oct 31.
Artículo en Inglés | MEDLINE | ID: mdl-37740280

RESUMEN

Herein, we demonstrate the construction of a 1D/2D heterostructure of cobalt phthalocyanine (CoPc)-carbon nitride (C3N4) for electrochemical N2 reduction to NH3. Improved performance originates from the higher exposure of active surface sites. The electrochemical NRR performance showed an NH3 formation rate of 423.8 µg h-1 mgcat-1, a high faradaic efficiency (FE) of 33%, and stability for 20 h. This study provides a new strategy for designing a highly efficient 1D/2D electrocatalytic system for ammonia synthesis.

5.
Diabetes Metab Syndr ; 17(1): 102703, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36634469

RESUMEN

AIM: This systematic review and meta-analysis was conducted to evaluate the efficacy and safety of lobeglitazone as compared to the standard of care (SOC) in patients with type 2 diabetes mellitus (T2DM). METHODS: Databases were searched for relevant randomized controlled trials. The primary outcome was the comparison of the glycated hemoglobin (HbA1C) level after 24 weeks. Pooled mean differences and odds ratios were calculated using random-effects models. RESULTS: Of 267 studies that were screened, four were included. Treatment with adjunct lobeglitazone showed a reduction in the HbA1C level [mean difference: -0.23% (95% CI: -0.62 to 0.16); p = 0.24; i2: 87%; moderate GRADE (Grading of Recommendations Assessment, Development and. Evaluation) of evidence], fasting blood glucose level [mean difference: -7.12 mg/dl (95% CI: -20.09 to 5.85); p = 0.28; i2: 87%; moderate GRADE of evidence], and lipid profile as compared to those following treatment with the SOC; however, the changes were not statistically significant. The risk of hypoglycemia was significantly lower [odds ratio: 0.24 (95% CI: 0.08 to 0.70); p < 0.05; i2: 0%; moderate GRADE of evidence] without any significant difference in the risk of drug-related adverse events [odds ratio: 1.59 (95% CI: 0.87 to 2.93); p = 0.13; i2: 0%; moderate GRADE of evidence] following treatment with lobeglitazone as compared to those following treatment with the SOC. CONCLUSION: Treatment with adjunct lobeglitazone showed changes in the blood glycemic status and lipid profile similar to SOC in patients with T2DM, and the results were not statistically significant. Lobeglitazone was well tolerated; its safety profile was comparable to SOC.


Asunto(s)
Diabetes Mellitus Tipo 2 , Hipoglucemiantes , Tiazolidinedionas , Humanos , Glucemia , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Hemoglobina Glucada , Hipoglucemiantes/uso terapéutico , Lípidos , Nivel de Atención , Tiazolidinedionas/uso terapéutico
6.
Geriatrics (Basel) ; 7(6)2022 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-36547272

RESUMEN

We assessed the association between polypharmacy and cardiovascular autonomic function among community-dwelling elderly patients having chronic diseases. Three hundred and twenty-one patients from an urban municipality area of Kolkata, India were studied in August 2022. The anticholinergic burden and cardiac autonomic function (Valsalva ratio, orthostatic hypotension, change in diastolic blood pressure after an isometric exercise, and heart rate variability during expiration and inspiration) were evaluated. Binary logistic regression analysis was performed to find out the association of polypharmacy and total anticholinergic burden with cardiac autonomic neuropathy. A total of 305 patients (age, 68.9 ± 3.4; 65.9% male) were included. Of these patients, 81 (26.6%) were on polypharmacy. Out of these 81 patients, 42 patients were on ninety-eight potential inappropriate medications. The anticholinergic burden and the proportion of patients with cardiac autonomic neuropathy were significantly higher among patients who were on polypharmacy than those who were not (8.1 ± 2.3 vs. 2.3 ± 0.9; p = 0.03 and 56.8% vs. 44.6%; p = 0.01). The presence of polypharmacy and a total anticholinergic burden of > 3 was significantly associated with cardiac autonomic neuropathy (aOR, 2.66; 95% CI, 0.91−3.98 and aOR, 2.51; 95% CI, 0.99−3.52, respectively). Thus, polypharmacy was significantly associated with cardiac autonomic neuropathy among community-dwelling elderly patients.

8.
Dalton Trans ; 51(34): 12904-12914, 2022 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-35946840

RESUMEN

The synthesis of nickel selenide nanostructures under ambient conditions remains fascinating, aesthetically beautiful, and energy efficient, as most reported methods involve high-temperature techniques. In this work, we have reported the wet chemical synthesis of NiSe2 nanostructures at room temperature. The approach starts with nickel nanowires (NiNW) and selenous acid as active ingredients. Upon the incubation of NiNW in selenous acid, zero-valent metallic nickel gradually oxidised with the successive deposition of nano-selenium, a reductive product, over the pristine NiNW surface. This thermodynamically controlled galvanic replacement reaction (GRR) is favourably governed by the reduction potential values of the Ni2+/Ni and SeO32-/Se redox couples. Moreover, the selenium nanoparticles over the NiNW surface and the oxidized Ni2+ underneath then interplay during inward and outward diffusion. The different diffusivities of the elements/ions cause the generation of void interiors, thus resulting in tubular nanostructures. Therefore, both the GRR and nanoscale Kirkendall effect jointly remain engaged, resulting in the formation of hollow NiSe2 nanotubular structures. Then, we ably exploit this heterogeneous chalcogenide nanostructure material as an artificial enzyme for peroxidase mimics. This provides a method for the naked-eye detection of peroxide in solution. The peroxidase activity was selectively restrained in the presence of glutathione. Hence, a colourimetric assay was simultaneously developed for the selective detection of this biothiol. The intrinsic nanozyme activity of the substrate is hitherto unknown and can, hence, be explored further with other nanostructured nickel selenide materials.


Asunto(s)
Níquel , Peroxidasa , Catálisis , Níquel/química , Ácido Selenioso , Temperatura
9.
Artículo en Inglés | MEDLINE | ID: mdl-30422758

RESUMEN

Azo linked salicyldehyde and a new 2-hydroxy acetophenone based ligands (HL1 and HL2) with their copper(II) complexes [Cu(L1)2] (1) and [Cu(L2)2] (2) were synthesized and characterized by spectroscopic methods such as 1H, 13C NMR, UV-Vis spectroscopy and elemental analyses. Calculation based on Density Functional Theory (DFT), have been performed to obtain optimized structures. Binding studies of these copper (II) complexes with calf thymus DNA (ct-DNA) and torula yeast RNA (t-RNA) were analyzed by absorption spectra, emission spectra and Viscosity studies and Molecular Docking techniques. The absorption spectral study indicated that the copper(II) complexes of 1 and 2 had intrinsic binding constants with DNA or RNA in the range of 7.6 ± 0.2 × 103 M-1 or 6.5 ± 0.3 × 103M-1 and 5.7 ± 0.4 × 104 M-1 or 1.8 ± 0.5 × 103 M-1 respectively. The synthesized compounds and nucleic acids were simulated by molecular docking to explore more details mode of interaction of the complexes and their orientations in the active site of the receptor.


Asunto(s)
Complejos de Coordinación/química , Complejos de Coordinación/metabolismo , Cobre/química , ADN/metabolismo , Unión Competitiva , Complejos de Coordinación/síntesis química , ADN/química , Teoría Funcional de la Densidad , Ligandos , Espectroscopía de Resonancia Magnética , Simulación del Acoplamiento Molecular , Estructura Molecular , ARN/química , ARN/metabolismo , Espectrometría de Fluorescencia , Espectrofotometría Ultravioleta , Espectroscopía Infrarroja por Transformada de Fourier , Viscosidad
10.
Spectrochim Acta A Mol Biomol Spectrosc ; 169: 108-15, 2016 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-27344521

RESUMEN

A pH dependent normal Raman scattering (NRS) and surface enhanced Raman scattering (SERS) spectral patterns of citrazinic acid (CZA), a biologically important molecule, have been investigated. The acid, with different pKa values (~4 and ~11) for the two different functional groups (-COOH and -OH groups), shows interesting range of color changes (yellow at pH~14 and brown at pH~2) with the variation in solution pH. Thus, depending upon the pH of the medium, CZA molecule can exist in various protonated and/or deprotonated forms. Here we have prescribed the existence different possible forms of CZA at different pH (Forms "C", "H" and "Dprot" at pH~14 and Forms "A", "D", and "P" at pH~2 respectively). The NRS spectra of these solutions and their respective SERS spectra over gold nanoparticles were recorded. The spectra clearly differ in their spectral profiles. For example the SERS spectra recorded with the CZA solution at pH~2 shows blue shift for different bands compared to its NRS window e.g. 406 to 450cm(-1), 616 to 632cm(-1), 1332 to 1343cm(-1) etc. Again, the most enhanced peak at ~1548cm(-1) in NRS while in the SERS window this appears at ~1580cm(-1). Similar observation was also made for CZA at pH~14. For example, the 423cm(-1) band in the NRS profile experience a blue shift and appears at ~447cm(-1) in the SERS spectrum as well as other bands at ~850, ~1067 and ~1214cm(-1) in the SERS window are markedly enhanced. It is also worth noting that the SERS spectra at the different pH also differ from each other. These spectral differences indicate the existence of various adsorptive forms of the CZA molecule depending upon the pH of the solution. Therefore based on the experimental findings we propose different possible molecular forms of CZA at different pH (acidic and alkaline) conditions. For example forms 'A', 'D' and 'P' existing in acidic pH (pH~2) and three other deprotonated forms 'C', 'H' and 'Dprot' in alkaline pH (pH~14). The DFT calculations for these prescribed model systems were also carried out to have a plausible understanding of their equilibrium geometries and the vibrational wavenumbers. An idea about the molecular orientation of the adsorbate over nanocolloidal gold substrate is also documented.

11.
Dalton Trans ; 44(1): 193-201, 2015 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-25369862

RESUMEN

We report an environmentally friendly synthetic strategy to fabricate reduced graphene oxide (rGO)-based ternary nanocomposites, in which glutathione (GSH) acts both as a reducing agent for graphene oxide and sulfur donor for CdS synthesis under modified hydrothermal (MHT) conditions. The report becomes interesting as pH variation evolves two distinctly different semiconducting nanocrystals of anatase/rutile TiO2 and hexagonal yellow/cubic red CdS, and their packaging makes them suitable photocatalysts for dye degradation. Herein, a titanium peroxo compound, obtained from commercial TiO2, is hydrolyzed to TiO2 nanostructures without any additives. The yellow colored CdS-TiO2-rGO (YCTG), one of the ternary photocatalysts, shows maximum efficiency compared to the corresponding red ternary CdS-TiO2-rGO or binary photocatalysts (CdS-rGO, TiO2-rGO and CdS-TiO2) for dye degradation under visible light irradiation. Systematic characterizations reveal that TiO2 presents at the interface of rGO and CdS in YCTG and thus makes a barrier that inhibits the direct interaction between rGO and CdS. This leads to a relatively higher bandgap value for CdS in YCTG (2.15 eV vs. 2.04 eV for CdS-rGO) but with better photocatalytic activity simply by diminishing the possibility of the charge-recombination process. In the present situation, rGO in the YCTG also supports faster dye degradation through higher dye adsorption and rapid internal electron transfer (CdS→TiO2→rGO) in the YCTG nanocomposite. Thus, a simple aqueous phase and a greener synthetic procedure results in a low-cost, highly effective visible light-responsive material for environmental application.


Asunto(s)
Compuestos de Cadmio/química , Glutatión/química , Grafito/química , Nanocompuestos/química , Óxidos/química , Sulfuros/química , Titanio/química , Catálisis , Colorantes/química , Conductividad Eléctrica , Luz , Modelos Moleculares , Nanocompuestos/ultraestructura , Oxidación-Reducción , Fotólisis , Sustancias Reductoras/química
12.
Langmuir ; 30(26): 7833-41, 2014 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-24926619

RESUMEN

Herein, we report a new strategy to remove toxic Cr(VI) ion from aqueous solution using metal-organic hybrid gel as sorbent. The gel could be easily synthesized from the commercially available organic ligand 2-mercaptobenzimidazole (2-MBIm) and copper(II) chloride in alcoholic medium. The synthesis involves one-electron reduction of Cu(II) to Cu(I) by 2-MBIm, and then gel formation is triggered through Cu(I)-ligand coordination and extensive hydrogen-bonding interactions involving the "-NH" protons (of 2-MBIm ligand), solvent molecules, and chloride ions. The gel shows entangled network morphology. Different microanalytical techniques (FTIR, powder XRD, FESEM, TEM, rheology etc.) have been employed for complete characterizations of the gel sample. Both Cu(I) (in situ formed) and Cl(-) ions trigger the gel formation as demonstrated from systematic chemical analyses. The gel also exhibits its stimuli-responsive behavior toward different interfering chemical parameters (pH, selective metal ions and anions, selective complexing agents, etc.). Finally the gel shows its redox-responsive nature owing to the distinguished presence of Cu(I) metal centers throughout its structural backbone. And this indeed helps in the effective removal of Cr(VI) ions from aqueous solution. Reduction of Cr(VI) to Cr(III) ions and its subsequent sorption take place in the gel matrix. The reductive removal of Cr(VI) has been quantitatively interpreted through a set of different kinetic measurements/models, and the removal capacity of the gel matrix has been observed to be ∼331 mg g(-1) at pH ∼ 2.7, which is admirably higher than the commonly used adsorbents. However, the capacity decreases with the increase in pH of the solution. The overall removal mechanism has been clearly demonstrated. Again, the gel could also be recycled. Thus, the low-cost and large-scale fabrication of the redox-active metallogel makes it an efficient matrix for the toxic ion removal and hence indicates the high promise of this new generation hybrid material for environmental pollution abatement.


Asunto(s)
Cromo/química , Cobre/química , Adsorción , Oxidación-Reducción , Espectroscopía Infrarroja por Transformada de Fourier , Contaminantes Químicos del Agua/química
13.
ACS Appl Mater Interfaces ; 6(12): 9134-43, 2014 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-24873275

RESUMEN

The importance of an interfacial reaction to obtain mesoporous leafy nanostructures of gold and palladium has been reported. A new synthetic strategy involving 1,4-dihydropyridine ester (DHPE) as a potential reducing agent performs exceptionally well for the desired morphologies of both the noble metals at room temperature. The DHPE in turn transforms into its oxidized aromatic form. The as-synthesized gold leaves exhibit high surface-enhanced Raman scattering activity with rhodamine 6G (R6G) due to their hyperbranched structure. It is worthwhile that as-synthesized porous architectures of palladium support the room-temperature hydrogenation of 4-nitrophenol (4-NP) by hydrazine hydrate (N2H4·H2O), reported for the first time. Furthermore, MPL exhibits exceptionally good catalytic activity toward electrooxidation of formic acid. Therefore, an aromaticity driven synthetic technique achieves a rationale to design leafy nanostructures of noble metals from the liquid-liquid interface for multifaceted applications.

14.
ACS Appl Mater Interfaces ; 6(9): 6308-16, 2014 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-24749894

RESUMEN

Thiourea (TU), a commercially available laboratory chemical, has been discovered to introduce metallogelation when reacted with copper(II) chloride in aqueous medium. The chemistry involves the reduction of Cu(II) to Cu(I) with concomitant oxidation of thiourea to dithiobisformamidinium dichloride. The gel formation is triggered through metal-ligand complexation, i.e., Cu(I)-TU coordination and extensive hydrogen bonding interactions involving thiourea, the disulfide product, water, and chloride ions. Entangled network morphology of the gel selectively develops in water, maybe for its superior hydrogen-bonding ability, as accounted from Kamlet-Taft solvent parameters. Complete and systematic chemical analyses demonstrate the importance of both Cu(I) and chloride ions as the key ingredients in the metal-organic coordination gel framework. The gel is highly fluorescent. Again, exclusive presence of Cu(I) metal centers in the gel structure makes the gel redox-responsive and therefore it shows reversible gel-sol phase transition. However, the reversibility does not cause any morphological change in the gel phase. The gel practically exhibits its multiresponsive nature and therefore the influences of different probable interfering parameters (pH, selective metal ions and anions, selective complexing agents, etc.) have been studied mechanistically and the results might be promising for different applications. Finally, the gel material shows a highly selective visual response to a commonly used nitroexplosive, picric acid among a set of 19 congeners and the preferred selectivity has been mechanistically interpreted with density functional theory-based calculations.

15.
J Mater Chem B ; 2(36): 6097-6105, 2014 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-32261862

RESUMEN

Mesoporous nickel oxide nanoflowers (NiO NFs) can be easily synthesized by a two-step synthetic procedure based on modified hydrothermal (MHT) treatment of nickel acetate and ethanol amine in water followed by thermal decomposition at 350 °C for 4 h. After thermal treatment, the porosity is increased by 18% with retention of parental nickel hydroxide size. In this study, for the first time, a new catalytic application of NiO NFs has been revealed in terms of peroxidase-like activity where colorless 3,3',5,5' tetramethylbenzidine (TMB) is oxidized to blue color product in the presence of H2O2 at room temperature. Comparative study confirms that mesoporous NiO NFs exhibit superior catalytic activity to the parent analogues, i.e. Ni(OH)2 or bulk NiO. This intrinsic peroxidase-like activity from an easily synthesized inorganic nanomaterial provides an alternative to horseradish peroxidase (HRP) enzyme. The lower Michaelis constant (Km) value indicates that the catalyst NiO NFs bind efficiently to the test substrate, i.e. TMB. Interestingly, the NiO NFs-catalyzed TMB oxidation, i.e. blue color formation, has been found to be selectively and successively inhibited by a variable amount of cysteine among a set of 21 congeners. Thus our adopted simple, low-cost and novel colorimetric assay stands to be a highly efficient approach for selective detection of cysteine with a limit of detection (LOD) value of ∼1.1 µM using a simple UV-vis spectrophotometer. The proposed method also exhibits outstanding selectivity and accuracy for N-acetyl cysteine (an analogue of cysteine) estimation in real pharmaceutical samples.

16.
ACS Appl Mater Interfaces ; 5(17): 8724-32, 2013 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-23947790

RESUMEN

Herein, a simple wet-chemical pathway has been demonstrated for the synthesis of silver nanoparticle conjugated reduced graphene oxide nanosheets where dimethylformamide (DMF) is judiciously employed as an efficient reducing agent. Altogether, DMF reduces both silver nitrate (AgNO3) and graphene oxide (GO) in the reaction mixture. Additionally, the presence of polyvinylpyrolidone (PVP) assists the nanophasic growth and homogeneous distribution of the plasmonic nanoparticle Ag(0). Reduction of graphene oxide and the presence of aggregated Ag NPs on reduced graphene oxide (rGO) nanosheets are confirmed from various spectroscopic techniques. Finally, the composite material has been exploited as an intriguing platform for surface enhanced Raman scattering (SERS) based selective detection of uranyl (UO2(2+)) ion. The limit of detection has been achieved to be as low as 10 nM. Here the normal Raman spectral (NRS) band of uranyl acetate (UAc) at 838 cm(-1) shifts to 714 and 730 cm(-1) as SERS bands for pH 5.0 and 12.0, respectively. This distinguished Raman shift of the symmetric stretching mode for UO2(2+) ion is indicative of pronounced charge transfer (CT) effect. This CT effect even supports the higher sensitivity of the protocol toward UO2(2+) over other tested oxo-ions. It is anticipated that rGO nanosheets furnish a convenient compartment to favor the interaction between Ag NPs and UO2(2+) ion through proximity induced adsorption even at low concentration.


Asunto(s)
Grafito/química , Nanoestructuras/química , Plata/química , Espectrometría Raman , Compuestos de Uranio/análisis , Dimetilformamida/química , Concentración de Iones de Hidrógeno , Iones/química , Nanopartículas del Metal/química , Oxidación-Reducción , Óxidos/química , Povidona/química
17.
J Colloid Interface Sci ; 398: 13-21, 2013 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-23473571

RESUMEN

The article reports a simple photoactivation technique for the synthesis of chain like assembly of spherical Au nanocrystals using a nontoxic biochemical, ß-cyclodextrin under ~365 nm UV-light irradiation. Under UV irradiation, ß-cyclodextrin acts as a reducing as well as capping agent and eventually becomes a stabilizing linker for Au nanoparticles. The UV-visible spectroscopy, transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), and X-ray photoelectron spectroscopic techniques are employed to systematically characterize the Au nanochains. Additionally, it is shown that the Au nanocrystals act as an effective catalyst for the reduction in nitrobenzene to aniline and methylene blue to leuco methylene blue in presence of suitable reducing agent. The catalytic reduction reactions and kinetic parameters are evaluated from UV-visible spectroscopy.

18.
Environ Sci Technol ; 47(5): 2339-45, 2013 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-23409805

RESUMEN

Phase pure spherical Sn-SnO2 nanoparticles (∼ 50 nm) in gram level have been synthesized from well-defined SnO microplates (∼ 2.0 µm) using focused solar irradiation. The first step of the reaction involves simple stirring of a strong NaOH solution with fine SnCl2·2H2O powder. Precipitated blue black microplates of SnO are finally transformed into high band gap Sn-SnO2 nanoparticles with sunlight. During the solid-state photodecomposition of microplates, spherical SnO2 nanoparticles along with tiny Sn(0) particles are evolved simultaneously. Tiny Sn(0) particles, improved surface area, stability toward adverse environmental conditions, and inherited negative surface charge electrostatically stabilize the Sn-SnO2 particle rendering it excellent water dispersible. The presence of Sn(0) nanoparticles in spherical SnO2 nanoparticles improves the charge (electrons and holes) separation efficiency. Then, the as-prepared particles selectively invite cationic dye molecules to the particle surface due to negative surface charge and degrade the dyes at a faster rate under UV light.


Asunto(s)
Colorantes/química , Nanopartículas del Metal/química , Luz Solar , Compuestos de Estaño/síntesis química , Agua/química , Procesos Fotoquímicos , Rayos Ultravioleta
19.
Chemistry ; 18(20): 6335-42, 2012 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-22473800

RESUMEN

In the present study, surface-enhanced Raman spectra of a bifunctional Raman reporter, 2-mercaptobenzimidazole, has been found to be responsive exclusively towards Cu(2+) ions while the reporter remains anchored on the Au nanoparticle surface. Thus a specific Cu(2+)-ion-detection protocol emerges. The simplicity, sensitivity, and reproducibility of the method allow routine and quantitative detection of Cu(2+) ions. An interference study involving a wide number of other metal ions shows the procedure to be uniquely selective and analytically rigorous. A theoretical study was carried out to corroborate the experimental results. Finally, the method is promising for real-time assessment of Cu(2+) ions in aqueous samples and also has the ability to discriminate Cu(I) and Cu(II) ions in solution.


Asunto(s)
Bencimidazoles/química , Cobre/análisis , Nanopartículas/química , Espectrometría Raman/métodos , Oro/química , Estructura Molecular , Soluciones/química , Estados Unidos , United States Environmental Protection Agency , Agua
20.
Langmuir ; 27(18): 11629-35, 2011 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-21809875

RESUMEN

Unique packaging of Ag(2)O on the surface of polycrystalline AgCl allows fabrication of a new useful, superhydrophobic composite material. This pure inorganic material with surface porosity of submicrometer aperture size fabricates air pockets, which make the composite material superhydrophobic. The new material behaves like lotus leaves, butterfly wings, or water strider's leg in relation to superhydrophobicity. Visible light induces photoreduction of solid Ag(2)O surface layer and generates Ag(0), making the composite surface superhydrophilic. Reoxidation of Ag(0) on the composite surface gives back the hydrophobicity that represents the redox-switchable wetting property of the material.

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