Simple non-basic solution route for the preparation of zinc oxide hollow spheres

Despite considerable efforts undertaken in a rapidly developing area of materials research, controlled synthesis of nanostructured ZnO is still a matter of intensive research. Herein, we report a facile base free approach for the fabrication of nanostructured ZnO hollow spheres. In the synthesis, ethylene glycol has been introduced as solvent and crystal-growth modifier and zinc acetate has been used as zinc precursor and also a source of soft template. ZnO nanoparticles of diameter â¼25 nm are assembled into highly regular hollow spheres. The powder X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive X-ray spectroscopy (EDS), photoluminescence (PL) and UV-visible spectroscopy have been used to characterize the crystal structure, morphology, composition and optical properties. Powder XRD pattern of ZnO confirms the formation of the wurtzite structure. Presence of oxygen deficiency in the prepared ZnO product is revealed by Raman and EDS studies. Strong emission at 422 nm with three weak emissions at 400, 484 and 529 nm were observed by PL spectrum. The growth mechanism for the formation of ZnO hollow spheres has been discussed on the basis of the growth model for the polar ZnO crystals. © 2012 Elsevier B.V

Flowering and fruit set in vanilla (Vanilla planifolia Andr.)

Cultivation of vanilla (Vanilla planifolia Andr.) is becoming increasingly popular in recent years in the hill zone of Karnataka, India. &nbsp

Comparison of the photocatalytic degradation of trypan blue by undoped and silver-doped zinc oxide nanoparticles

Zinc oxide (ZnO) and silver doped zinc oxide (ZnO:Ag) nanoparticles were prepared using nitrates of zinc and silver as oxidizers and ethylene diaminetetraacetic acid (EDTA) as a fuel via low-temperature combustion synthesis (LCS) at 500 degrees C. X-ray diffraction (XRD) pattern indicates the presence of silver in the hexagonal wurtzite structure of ZnO. Fourier transform infrared (FTIR) spectrum indicates the presence of Ag-Zn-O stretching vibration at 510 cm(-1). Transmission electron microscopy (TEM) images shows that the average particle size of ZnO and ZnO:Ag nanoparticles were found to be 58 nm and 52 nm, respectively. X-ray photoelectron spectroscopy (XPS) data clearly indicates the presence of Ag in ZnO crystal lattice. The above characterization techniques indicate that the incorporation of silver affects the structural and optical properties of ZnO nanoparticles. ZnO:Ag nanoparticles exhibited 3% higher photocatalytic efficiency than pure ZnO nanoparticles. ZnO:Ag nanoparticles show better photocatalytic activity for the degradation of trypan blue (TrB) compared to undoped ZnO nanoparticles. (C) 2014 Elsevier Ltd. All rights reserved

Global Perspectives on Task Shifting and Task Sharing in Neurosurgery.

BACKGROUND: Neurosurgical task shifting and task sharing (TS/S), delegating clinical care to non-neurosurgeons, is ongoing in many hospital systems in which neurosurgeons are scarce. Although TS/S can increase access to treatment, it remains highly controversial. This survey investigated perceptions of neurosurgical TS/S to elucidate whether it is a permissible temporary solution to the global workforce deficit. METHODS: The survey was distributed to a convenience sample of individuals providing neurosurgical care. A digital survey link was distributed through electronic mailing lists of continental neurosurgical societies and various collectives, conference announcements, and social media platforms (July 2018-January 2019). Data were analyzed by descriptive statistics and univariate regression of Likert Scale scores. RESULTS: Survey respondents represented 105 of 194 World Health Organization member countries (54.1%; 391 respondents, 162 from high-income countries and 229 from low- and middle-income countries [LMICs]). The most agreed on statement was that task sharing is preferred to task shifting. There was broad consensus that both task shifting and task sharing should require competency-based evaluation, standardized training endorsed by governing organizations, and maintenance of certification. When perspectives were stratified by income class, LMICs were significantly more likely to agree that task shifting is professionally disruptive to traditional training, task sharing should be a priority where human resources are scarce, and to call for additional TS/S regulation, such as certification and formal consultation with a neurosurgeon (in person or electronic/telemedicine). CONCLUSIONS: Both LMIC and high-income countries agreed that task sharing should be prioritized over task shifting and that additional recommendations and regulations could enhance care. These data invite future discussions on policy and training programs

Plant Growth-Promoting Microbes from Herbal Vermicompost

Overreliance on chemical pesticides and fertilizers has resulted in problems including safety risks, outbreaks of secondary pests normally held in check by natural enemies, insecticide resistance, environmental contamination, and decrease in biodiversity. The increasing costs and negative effects of pesticides and fertilizers necessitate the idea of biological options of crop protection and production. This includes the use of animal manure, crop residues, microbial inoculum, and composts. They provide natural nutrition, reduce the use of inorganic fertilizers, develop biodiversity, increase soil biological activity, maintain soil physical properties, and improve environmental health

Electrochemical Generation of Zn2SnO4 Photocatalyst for Degradation of Methylene Blue

In this paper, a simple two-step hybrid electrochemical-thermal route was developed for the synthesis of cubic shaped Zn2SnO4 (ZTO) nanoparticles using aqueous sodium bicarbonate (NaHCO3) and sodium stannate (Na2SnO3) as an electrolyte. The sacrificial Zinc metal was used as both anode and cathode in an undivided cell under galvanostatic mode at room temperature. The bath concentration and current density were respectively varied from 30 to 120 mmol and 0.05 to 1.5 A/dm2 . The electrochemically generated precursor was calcined for an hour at different range of temperatures from 60 to 500°C. The crystallite sizes in the range of 24-53 nm were calculated based on the Debye-Scherrer equation. Scanning electron microscopy results reveal that all the particles have cubic morphology with a diameter of 40- 50 nm. The as-prepared ZTO nanoparticles showed higher catalytic activity towards the degradation of methylene blue (MB) dye, and the 90% degradation was found for the sample calcined at 500 °C, which is greater than that of commercial TiO2-P25 photocatalysts. Theseresults indicate that the ZTO nanoparticles may be employed to remove dyes from waste water

Extractive spectrophotometric determination of molybdenum(V) in molybdenum steels

An extraction spectrophotometric method has been developed for the determination of traces of molybdenum present in molybdenum steels which is based on the extraction of the orange-red molybdenum-thiocyanate-acetonethiosemicarbazone complex into chloroform from hydrochloric acid medium. The complex has an absorption maximum at 472 nm with a molar absorptivity of 1.9 × 104 liters mol−1 cm−1. Beer's law is valid over the concentration range 0.1–9.5 ppm of molybdenum with an optimum concentration range of 0.4–9 ppm. The equilibrium shift method indicates 1:4:2 composition for molybdenumthiocyanate-acetonethiosemicarbazone complex. The effect of acidity, reagent concentrations, temperature, and interferences from various ions are reported

Structural features of biologically active coordination compounds of vanillinsemicarbazone

Complexes of vanillinsemicarbazone (VSC) with MnII, FeII, CoII, NiII, CuII, ZnII, CdII and HgII have been prepared and characterised by elemental analyses, molar conductance, magnetic susceptibility and spectral data. Probable structures for the complexes are suggested on the basis of their physico-chemical properties. The fungitoxicity of VSC and the isolated complexes have been tested on pathogenic fungi. © 1985 VCH Verlagsgesellschaft mbH