Ultrasmall Plasmonic Nanoparticles Decorated Hierarchical Mesoporous TiO2 as an Efficient Photocatalyst for Photocatalytic Degradation of Textile Dyes.

Hierarchical mesoporous TiO2 was synthesized via a solvothermal technique. The sonochemical method was adopted to decorate plasmonic nanoparticles (NPs) (Ag, Au) on the pores of mesoporous TiO2. The crystallinity, structure, and morphology were determined to understand the physicochemical nature of the nanocomposites. The catalytic efficiency of the plasmonic nanocatalysts was tested for the azo dyes (congo red, methyl orange, acid orange 10, and remazol red) under solar and visible light irradiations. The generation of hydroxyl radicals was also studied using terephthalic acid as a probe molecule. An attempt was made to understand the influence of size, work function and Fermi level of the metal NPs toward the efficiency of the photocatalyst. The efficiency of the nanocomposites was found to be in the order of P25 < mesoporous TiO2 < mesoporous Ag-TiO2 < mesoporous Au-TiO2 nanospheres under both direct solar light and visible light irradiation. The results indicated that the adsorption of dye, anatase phase, and surface plasmon resonance of NPs favored the effective degradation of dyes in aqueous solution. Further, the efficiency of the catalyst was also tested for xanthene (rose bengal), rhodamine (rhodamine B, rhodamine 6G), and thiazine (methylene blue) dyes. Both TiO2 and NPs (Ag & Au) possess a huge potential as an eco-friendly photocatalyst for wastewater treatment.

µ-(2,6-Bis{[3-(di-methyl-amino)-prop-yl]imino-meth-yl}-4-methyl-phenolato)-µ-hydroxido-bis-[(thio-cyanato-κN)copper(II)].

In the title compound, [Cu2(C19H31N4O)(OH)(NCS)2], the mol-ecular structure of the dinuclear complex reveals two penta-coordinated Cu(II) ions, which are bridged by the phenolate O atom of the ligand and by an exogenous hydroxide ion. The bridging atoms occupy equatorial positions in the coordination sphere of the metal atoms and complete the equatorial coordination planes with two ligand N atoms, the apical positions being occupied by thio-cyanate N atoms. The crystal structure also features π-π stacking inter-actions involving the benzene rings with a centroid-centroid distance of 3.764 (4)Å. The crystal studied was a non-merohedral twin, with a refined BASF value of 0.203 (2).

Nutrition transition in a middle-income country: 22-year trends in the Seychelles.

BACKGROUND/OBJECTIVES: There is little objective information regarding nutrition transition in African countries. We assessed trends in nutrition patterns in the Seychelles between 1989 and 2011. SUBJECTS/METHODS: Population-based samples were obtained in 1989, 1994 and 2011 and participants aged 25-44 are considered in this study (n=493, 599 and 471, respectively). Similar, although not identical, food frequency questionnaires (FFQs) were used in each survey and the variables were collapsed into homogenous categories for the purpose of this study. RESULTS: Between 1989 and 2011, consumption frequency of fish (5+/week) decreased from 93 to 74%, whereas the following increased: meat (5+/week) 25 to 51%, fruits (1+/week) 48 to 94%, salty snacks (1+/week) 22 to 64% and sweet snacks (1+/week) 38 to 67% (P<0.001 for all). Consumption frequency decreased for home-brewed alcoholic drinks (1+/week) 16 to 1%, but increased for wine (1+/week) 5 to 33% (both P<0.001). Between 2004 and 2011, consumption frequency decreased for rice (2/day) 62 to 57% and tea (1+/day) 72 to 68%, increased for poultry (1+/week) 86 to 96% (all P<0.01), and did not change for vegetables (70.3 to 69.8%, P=0.65). CONCLUSIONS: Seychelles is experiencing nutrition transition characterized by a decreased consumption frequency of traditional staple foods (fish, polished rice), beverages (tea) and of inexpensive home brews, and increased consumption frequency of meat, poultry and snacks. Food patterns also became more varied along with a broader availability of products in the 22-year interval. The health impact of these changes should be further studied.

Enhanced catalytic activity of zeolite encapsulated Fe(III)-Schiff-base complexes for oxidative coupling of 2-napthol.

Iron(III) Schiff-base complexes of general formula [Fe(L)(2)Cl]·2H(2)O, where L = N,N-bis(salicylidene)ethylenediamine and N,N-disalicylidene-1,2-phenylenediamine have been encapsulated within various alkali exchanged zeolites viz. LiY, NaY, and KY by flexible ligand method. The encapsulated complexes are characterized by EDX, scanning electron microscopy (SEM), powder X-ray diffraction (XRD), FT-IR, UV-vis, diffuse reflectance spectroscopy (DRS), electron spin resonance spectroscopy (ESR) and cyclic voltammetry studies. The diffuse reflectance UV-vis spectra of encapsulated complexes show a dramatic red shift of the charge transfer band with increasing electropositivity of the exchangeable cations. The electrochemical analysis predicts the shifting of the reduction potential toward negative values with increasing size of the alkali exchanged cations. The zeolite encapsulated Schiff-base complexes of iron are found to be catalytically active toward the oxidative coupling of 2-napthol. Metal complexes incorporated in potassium exchanged zeolite-Y are found to be more effective for catalytic conversion of 2-naphthol to binaphthol and induces higher selectivity toward the R-conformation. The catalytic conversion of 2-napthol to BINOL is found to depend on the reduction potential of the catalyst, with a more negative reduction potential being better for the catalytic conversion. Density functional calculation is being carried out on both the neat Fe-Salen and Fe-Salophen complexes and those encapsulated in NaY zeolite to investigate change in structural parameters, energies of the HOMO and LUMO, and global hardness and softness. Fukui functions, as local descriptors, are used to analyze the hard-hard interaction at a particular site of the complexes.

Impact of different adiposity measures on the relation between serum uric acid and blood pressure in young adults.

Serum uric acid (SUA) concentration is independently associated with blood pressure (BP) in adults. We examined this association in young adults at an age where anti-hypertension treatment, other potential confounding factors and co-morbidity are unlikely to occur. We assessed BP, anthropometric variables including weight, height, waist circumference (WC), body fat percent (using bioimpedance), lifestyle behaviors, SUA and blood lipids in 549 participants aged 19-20 years from a population-based cohort study (Seychelles Child Development Study). Mean (s.d.) SUA was higher in males than females, 0.33 (0.08) and 0.24 (0.07) mmol l(-1), respectively. Body mass index (BMI) was higher in females than males but BP was markedly higher in males than in females. SUA was associated with both systolic and diastolic BP. However, the magnitude of the linear regression coefficients relating BP and SUA decreased by up to 50% upon adjustment for BMI, WC or body fat percent. The association between SUA and BP was not altered upon further adjustment for alcohol intake, smoking, triglycerides or renal function. In fully adjusted models, SUA remained associated with BP (P<0.05) in females. In conclusion, adiposity substantially decreased the association between SUA and BP in young adults, and BP was independently associated with SUA in females. These findings suggest a role of adiposity in the link between hyperuricemia and hypertension.

Microemulsion synthesis and electrocatalytic properties of carbon-supported Pd-Co-Au alloy nanoparticles.

Carbon-supported Pd and Pd-Co-Au alloy electrocatalysts are prepared by water-in-oil microemulsion technique using water as aqueous phase, non-ionic Triton-X-100 as surfactant, and cyclohexane as oil phase. The materials are characterized using XRD, TEM, and EDX. Face-centered cubic structure of Pd and presence of respective elements with controllable composition is evident from the analysis of XRD and EDX. The role of alloying elements on the redox behavior as well as catalytic activity of Pd is studied by cyclic voltammetry and ultraviolet photoelectron spectroscopy. Electrochemical measurements performed by rotating disk electrode voltammetry indicate the good ORR activity of Pd-Co-Au/C compared to Pd/C.

Biosynthesis of silver nanoparticles using citrus sinensis peel extract and its antibacterial activity.

Biosynthesis of silver nanoparticles (AgNPs) was achieved by a novel, simple green chemistry procedure using citrus sinensis peel extract as a reducing and a capping agent. The effect of temperature on the synthesis of silver nanoparticles was carried out at room temperature (25°C) and 60°C. The successful formation of silver nanoparticles has been confirmed by UV-vis, FTIR, XRD, EDAX, FESEM and TEM analysis and their antibacterial activity against Escherichia coli, Pseudomonas aeruginosa (gram-negative), and Staphylococcus aureus (gram-positive) has been studied. The results suggest that the synthesized AgNPs act as an effective antibacterial agent.

Synthesis of different architectures like stars, multipods, ellipsoids and spikes of zinc oxide by surfactantless precipitation.

Zinc oxide with different morphologies like stars, multipods, ellipsoids and spikes was synthesized using zinc nitrate and sodium hydroxide in the absence of surfactants. Seed mediation was found to be essential for the formation of ZnO nanospikes. Synthesized ZnO samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), UV-visible diffuse reflectance spectroscopy (UV-vis-DRS) and energy dispersive analysis by X-rays (EDAX) techniques. The predominant c-axis growth of hexagonal lattice was observed in ZnO anisotropic particles. TEM analysis revealed the formation of two types of ZnO ellipsoid particles. Concentration of the reactants was found to have a role in controlling the morphology of the resulting ZnO. Mechanism of formation of varying morphologies of ZnO particles has been proposed.

Fabrication of Worm-Like Nanorods and Ultrafine Nanospheres of Silver Via Solid-State Photochemical Decomposition.

Worm-like nanorods and nanospheres of silver have been synthesized by photochemical decomposition of silver oxalate in water by UV irradiation in the presence of CTAB and PVP, respectively. No external seeds have been employed for the synthesis of Ag nanorods. The synthesized Ag colloids have been characterized by UV-visible spectra, powder XRD, HRTEM, and selected area electron diffraction (SAED). Ag nanospheres of average size around 2 nm have been obtained in the presence of PVP. XRD and TEM analyses revealed that top and basal planes of nanorods are bound with {111} facets. Williamson-Hall plot has revealed the presence of defects in the Ag nanospheres and nanorods. Formation of defective Ag nanocrystals is attributed to the heating effect of UV-visible irradiation.

Single-step synthesis and structural study of mesoporous sulfated titania nanopowder by a controlled hydrolysis process.

An environmentally benign route for the single-step synthesis of mesoporous sulfated titania is described by a seeding method using titanium oxysulfate as the titania source. The hydrolysis was performed in the presence of NaOH and seed under constant-volume conditions around 98 degrees C. The XPS and DRIFT spectra show the existence of a bridged bidentate sulfate complex on the surface of titania. The elimination of sulfur on heat treatment showed a characteristic change in mesoporosity, specific surface area, and crystallinity of the material. The transformation of sulfated titania to anatase was incomplete at 900 degrees C, showing a delay in crystallization due to the presence of sulfur. Studies on the thermal stability of the sulfated titania showed that the material obtained can be used for various applications at temperatures below 300 degrees C. The ammonia-TPD and catalytic performance studies of the sulfated titania samples showed the presence of strong acid sites.

A Rapid Synthesis of Oriented Palladium Nanoparticles by UV Irradiation.

Palladium nanoparticles of average size around 8 nm have been synthesized rapidly by UV irradiation of mixture of palladium chloride and potassium oxalate solutions. A rod-shaped palladium oxalate complex has been observed as an intermediate. In the absence of potassium oxalate, no Pd nanoparticles have been observed. The synthesized Pd nanoparticles have been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), selective area electron diffraction and energy dispersive analysis by X-rays (EDAX) analyses. XRD analysis indicates the preferential orientation of catalytically active {111} planes in Pd nanoparticles. A plausible mechanism has been proposed for the formation of anisotropic Pd nanoparticles.

Microwave-assisted rapid synthesis of anisotropic Ag nanoparticles by solid state transformation.

Anisotropic silver nanoparticles (NPs) have been synthesized rapidly using microwave irradiation by the decomposition of silver oxalate in a glycol medium using polyvinyl pyrolidone (PVP) as the capping agent. The obtained Ag nanoparticles have been characterized by UV-visible spectroscopy, powder x-ray diffraction (XRD), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) studies. Anisotropic Ag nanoparticles of average size around 30 nm have been observed in the case of microwave irradiation for 75 s whereas spherical particles of a size around 5-6 nm are formed for 60 s of irradiation. The texture coefficient and particle size calculated from XRD patterns of anisotropic nanoparticles reveal the preferential orientation of (111) facets in the Ag sample. Ethylene glycol is found to be a more suitable medium than diethylene glycol. A plausible mechanism has been proposed for the formation of anisotropic Ag nanoparticles from silver oxalate.

Electro-oxidation of methanol on TiO2 nanotube supported platinum electrodes.

TiO2 nanotubes have been synthesized using anodic alumina membrane as template. Highly dispersed platinum nanoparticles have been supported on the TiO2 nanotube. The supported system has been characterized by electron microscopy and electrochemical analysis. SEM image shows that the nanotubes are well aligned and the TEM image shows that the Pt particles are uniformly distributed over the TiO2 nanotube support. A homogeneous structure in the composite nanomaterials is indicated by XRD analysis. The electrocatalytic activity of the platinum catalyst supported on TiO2 nanotubes for methanol oxidation is found to be better than that of the standard commercial E-TEK catalyst.

Thermal decomposition as route for silver nanoparticles.

Single crystalline silver nanoparticles have been synthesized by thermal decomposition of silver oxalate in water and in ethylene glycol. Polyvinyl alcohol (PVA) was employed as a capping agent. The particles were spherical in shape with size below 10 nm. The chemical reduction of silver oxalate by PVA was also observed. Increase of the polymer concentration led to a decrease in the size of Ag particles. Ag nanoparticle was not formed in the absence of PVA. Antibacterial activity of the Ag colloid was studied by disc diffusion method.

Diagnostic plots for assessing the frailty distribution in multivariate survival data.

In biomedical studies, frailty models are commonly used in analyzing multivariate survival data, where the objective of the study is to estimate both the covariate effect and the dependence between the multivariate survival times. However, inference based on these models are dependent on the distributional assumption of frailty. We propose a diagnostic plot for assessing the frailty assumption. The proposed method is based on the cross-ratio function and the diagnostic plot suggested by Oakes (1989). We use kernel regression smoothing with bandwidth choice by cross-validation, to obtain the proposed plot. The resulting plot is capable of differentiating between the gamma and positive stable frailty models when strong association is present. We illustrate the feasibility of our method using simulation studies under known frailty distributions. The approach is applied to data on blindness for each eye of diabetic patients with adult onset diabetes and a reasonable fit to the gamma frailty model is found.

Endothelial cells enhance spontaneous metastasis of human lung carcinoma cells in athymic mice.

The process of adhesion to endothelial cells is an important step in the progression to metastatic disease. The use of human neoplastic cell lines (now increasingly used in the study of the mechanisms of metastasis) in studying interactions with normal endothelial cells is therefore pertinent. In this report, the enhanced ability of a metastatic variant, MV522, of a human lung carcinoma cell line to adhere to endothelial cell monolayers is demonstrated. The ability to spontaneously metastasize from subcutaneous sites in athymic mice, of in vitro selected endothelial adhesive subpopulations of MV522 is also shown.