Quantitative Analysis of Photo-Thermal Stability of CdSe/CdS Core-Shell Nanocrystals

We report here investigations on the instability in luminescence of bare (TOPO-stabilized) and CdS- capped CdSe particles under infrared radiation. During photo-thermal annealing the formation of oxide layers on the surfaces of the particles create defect states. Consequently there is a reduction in particle size. These two effects control the light output from the samples. We make a quantitative comparison of the stability of bare CdSe and core-shell type CdSe-CdS particles under photo-annealing. Using diffusion theory, we show that the volume of the oxide layer, adhered to the crystallites, play a dominant role in controlling the luminosity of the particles.Comment: 10 pages, 4 figure

Assessing water resources sustainability in Middle East and North Africa

Abstract. The Middle East and North Africa (MENA) areas are the driest regions with the most water rare districts on the planet, with a territorial yearly normal of 1,200 cubic meters for every individual (world normal is near 7,000). And also, population and poverty are increasing at an alarming rate, increasing the demand for food, water assets are ending up progressively rare, desertification is a general natural issue, Desalination is an abuse of water assets in the Middle East. The shortages of water are compounded by the degradation of the quality of water. Over-abstraction of groundwater is always meet with high water stress. While farming and the countryside economy are imperative components in the MENA nations, the general commitment of farming to by and large GDP in most nations is low and has been declining. Raising water efficiency in light of the new evapotranspiration (ET) water the board worldview requests something other than changes in water system innovation. It requires coordinated consideration for improving specialized, agronomic, and the executives’ measures. Water User Associations (WUAs) incredibly encourage the usage of coordinated measures. Utilizing satellite remote detecting advances, organizers, and arrangement producers can make progressively powerful choices to guarantee a steady supply of water for sustenance and the earth

Gender and informal sector analysis in India: Economy wide approaches

The main purpose of this paper is to look at the incorporation of gender and the informal sector within a general equilibrium framework for India. Moreover, we clarify some important links between a gender aware informal sector based social accounting matrix (SAM) and general equilibrium models such as the computable general equilibrium (CGE) models including as a special case the fixed price multiplier (FPM) models. In particular, economy wide modelling of gender and the informal sector is facilitated by the use of national level data and constructing the base data set as an SAM. Another important strategy is to conceptualize the economy within gender structures, entailing the recognition of gender relations as an intervening variable in all economic activities

Spectrophotometric estimation of nitro tyrosine by azo-coupling reaction

3-Nitrotyrosine has been identified using techniques like immunohistochemistry, HPLC, GCMS to demonstrate as a relevant biomarker in various disorders such as neurological, cardiovascular and others. Estimation of 3-NT by spectrophotometric method has been performed to measure 3-NT over decades. However none of the above methods have been translated to diagnose the diseases, but pathological conditions. Therefore here is an attempt to develop a method to be employed as a diagnostic tool. Current work is focussed on including preparation of 3-NT and further to derivatives using β-Napthol to yield diazotised product. All these intermediates of diazotized products have been characterized by ESI MS and the final colored dye was measured spectrophotometrically which exhibits λ max at 551 nm. The dye has been measured and compared with the direct measurement of 3-NT. The sensitivity of measurement of 3-NT increases by 10 fold, by and large we can estimate 20 μM concentration of 3-NT

A non-destructive analytic tool for nanostructured materials : Raman and photoluminescence spectroscopy

Modern materials science requires efficient processing and characterization techniques for low dimensional systems. Raman spectroscopy is an important non-destructive tool, which provides enormous information on these materials. This understanding is not only interesting in its own right from a physicist's point of view, but can also be of considerable importance in optoelectronics and device applications of these materials in nanotechnology. The commercial Raman spectrometers are quite expensive. In this article, we have presented a relatively less expensive set-up with home-built collection optics attachment. The details of the instrumentation have been described. Studies on four classes of nanostructures - Ge nanoparticles, porous silicon (nanowire), carbon nanotubes and 2D InGaAs quantum layers, demonstrate that this unit can be of use in teaching and research on nanomaterials.Comment: 32 pages, 13 figure

Raman and photoluminescence studies on thermally annealed porous silicon

We report Raman and Photoluminescence (PL) studies of porous silicon (PS) as a function of isochronal thermal annealing from room temperature to 900°C. The PL peak position and intensity show nonmonotonic variation with increasing temperature. The PL intensity first increases upto 100°C, then decreases till 550°C and recovers its intensity at 700 °C before it completely disappears at 800 °C. The red shifted asymmetric Raman line shape can be fitted by phonon confinement model along with the disordered silicon component. Our results clearly indicate that the origin of visible PL can be better explained by a new hybrid model which incorporates both nanostructures for quantum confinement and silicon complexes (such as SiHx and siloxene) and defects at Si/SiO2 interfaces as luminescent centres

Electron and Phonon Confinement and New Surface Phonon Modes in CdSe-CdS Core-Shell Nanocrystals

Optical and vibrational properties of bare and CdS shelled CdSe nanocrystalline particles are investigated. To confirm the formation of such nanocrystals in our samples we estimate their average particle sizes and size distributions using TEM measurements. From the line profile analysis of the images the core-shell structure in the particles has been confirmed. The blue shift in optical absorption spectra, analyzed using theoretical estimates based on the effective bond order model, establishes the electron confinement in the nanoparticles. Unique characteristics of the nanocrystals (which are absent in the corresponding bulk material), such as confinement of optical phonons and the appearance of surface phonons, are then discussed. Making use of the dielectric response function model we are able to match the experimental and theoretical values of the frequencies of the surface phonons. We believe that our studies using optical probes provide further evidence on the existence of core-shell structures in CdSe-CdS type materials.Comment: 19 pages 8 figure

A systematic literature review on cyberstalking. An analysis of past achievements and future promises

Individuals’ excessive use of technology-enabled communication platforms, such as social media, has led to scholarly recognition of rising incidences of cyberstalking. Despite considerable studies directed at its examination, the current research on cyberstalking is limited by a lack of clarity on its characterization and prevalence, coupled with a fragmented research focus. To address this limitation, a Systematic Literature Review (SLR) on cyberstalking has been undertaken. Rigorous protocols were applied to identify 49 empirical studies via Scopus and Web of Science, based on specific keywords and article selection criteria. Findings reveal four emergent research themes on characteristics and roles of cyberstalkers, victims, parents, social media, and online service providers, as well as reporting, coping, and prevention strategies discussed in prior studies. Findings imply the need for temporal and cross-cultural validation of measurement scales and prior results by developing sophisticated, theoretically-grounded frameworks. Based on study findings, a research framework is proposed to assist researchers in future examinations of under-investigated associations and constructs. Implications arise for studying potential pre-emptive factors to address cyberstalking at a societal level by disseminating appropriate information to the general public. There is a need to develop stringent legislation and to induce service providers' active participation to prevent cyberstalking.publishedVersio

Single cell preparations of Mycobacterium tuberculosis damage the mycobacterial envelope and disrupt macrophage interactions

For decades, investigators have studied the interaction o

A systematic literature review on cyberstalking. An analysis of past achievements and future promises

Individuals’ excessive use of technology-enabled communication platforms, such as social media, has led to scholarly recognition of rising incidences of cyberstalking. Despite considerable studies directed at its examination, the current research on cyberstalking is limited by a lack of clarity on its characterization and prevalence, coupled with a fragmented research focus. To address this limitation, a Systematic Literature Review (SLR) on cyberstalking has been undertaken. Rigorous protocols were applied to identify 49 empirical studies via Scopus and Web of Science, based on specific keywords and article selection criteria. Findings reveal four emergent research themes on characteristics and roles of cyberstalkers, victims, parents, social media, and online service providers, as well as reporting, coping, and prevention strategies discussed in prior studies. Findings imply the need for temporal and cross-cultural validation of measurement scales and prior results by developing sophisticated, theoretically-grounded frameworks. Based on study findings, a research framework is proposed to assist researchers in future examinations of under-investigated associations and constructs. Implications arise for studying potential pre-emptive factors to address cyberstalking at a societal level by disseminating appropriate information to the general public. There is a need to develop stringent legislation and to induce service providers' active participation to prevent cyberstalking.</p