Spray deposition and characterization of nanostructured Li doped NiO thin films for application in dye-sensitized solar cells

Transparent conducting Li (0-5?wt%) doped NiO thin films with preferential growth along the (111) plane were deposited onto glass substrates by pyrolytic decomposition of nickel nitrate and lithium chloride precursors at 500?°C in air. The effect of Li concentration on the structural, optical and transport properties of NiO thin films was studied by x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), spectral transmittance, photoluminescence and linear four-probe resistivity. Activation energies as a function of Li concentration were deduced from the temperature dependent resistivity data measured in the range 300-448?K. The figure of merit was deduced by combining the spectral transmittance and sheet resistance values. The variation in properties of NiO thin film due to Li doping are discussed based on the above results. A dye-sensitized solar cell has also been fabricated for the optimized Li doped NiO thin film and the results are presented.     

GA Optimized HMM Error Model for OFDM

Finite-state HMM error models are an established powerful tool for capturing temporal characteristics of fading channels. They make network simulations much more practical and fast while developing and testing higher layer wireless system protocols and designing interleaving and FEC schemes. This paper has introduced two new Genetic Algorithm (GA) based approaches, namely, GA-S and GA-B as an alternative to HMM error models, for the accurate learning of error statistics of autocorrelation function (ACF) and error-run distributions. Validity comparisons of fit obtained show that the GA method is better than both the conventional Baum–Welch algorithm (BWA) and Semi-hidden Markov model (SHMM) methods, even when the target sequences are as short as 1000 in length. The independent elements of the [A] and [B] parameters of BWA used as chromosomes of the population space are used for error generation within the Genetic Algorithm. Mean square error of statistical properties of the error sequences is used to determine fitness of the chromosomes unlike other works using average log-likelihood ratio. Applicability has been tested by numerical simulations using error sequences of different lengths as well as target sequences of fixed length from an OFDM transceiver system under different fading rates. A T _s spaced time-delay model of the propagation channel with a fixed power delay profile has been used. For slow faded channels or when long sequences of error free intervals poses difficulties for BWA training, the GA method proves to be an excellent alternative for fast and accurate modeling of the error bursts. Unlike the computationally cumbersome BWA or the simplified SHMM approach, the GA model is capable of arriving at desired levels of accuracy with two to three states, in contrast to the Markov models needing a much higher number of states.

     

Harmine-loaded galactosylated pluronic F68-gelucire 44/14 mixed micelles for liver targeting

Harmine (HM), a phytoconstituent has wide range of pharmacological activities including antimicrobial, antifungal, antioxidative, and anticancer. HM has shown promising anticancer activity against liver cancer cells. However, poor aqueous solubility, multidrug pump P-gp efflux, extensive in vivo metabolism, and rapid elimination due to glucuronidation/sulfation limit clinical utility of HM. In order to overcome the drawbacks of HM, the current work reports preparation of HM-loaded galactosylated pluronic F-68 (PF68)-Gelucire^® 44/14 (GL44) mixed micelles (HM-MM). 3² factorial design was used to investigate the effect of formulation variables on formation HM-loaded mixed micelles. Solvent evaporation method was used for preparation of HM-MM. The optimized HM-MM was evaluated for size, percent drug entrapped (EE), in vitro HM release, oral bioavailability, and biodistribution in rats. HM-MM with an average size 277.5?±?3.24?nm had an EE of 86.5?±?1.51% w/w. HM-MM released HM in a controlled manner. Additionally, HM-MM showed significant enhancement in oral bioavailability (around six-folds) of HM when compared to HM alone. Further, HM-MM showed around sevenfold higher amount of HM in the liver when compared to HM alone revealing efficient drug targeting capability. Such significant improvement in oral bioavailability of HM when formulated into mixed micelles could be attributed to solubilization of hydrophobic HM into micellar core along with P-gp inhibition effect of both galactosylated PF68 and GL44. Thus, the present work highlights galactosylated PF68 and GL44 mixed micelles as an efficient carrier system having drug targeting capability and potential to enhance bioavailability of BCS class II drugs.     

Social and institutional factors in adjustment to traumatic brain injury.

ABSTRACT. A longitudinal case study of a working-class heterosexual White man who sustained a traumatic brain injury in a motor vehicle accident is used to delineate social and institutional factors that play a role in adjustment to brain injury. Data gathered from multiple sources (e.g., medical records, neuropsychological assessment, participant observation, and interviews) and sustained contact with the participant and his family over a 10-month time span reveal a complex and multidetermined view of the adjustment process. The case illustrates the critical need for an advocate, a requirement that becomes particularly acute when cognitive disabilities interfere with a person's ability to function effectively on his or her own. The factors that people with brain injuries and advocates must face include shifting of responsibilities, time, paperwork, negotiation of finances, and issues related to class and disability status. Moving beyond the individual focus on deficits and impairments to looking at the institutional, social, and cultural factors that influence the adjustment process will give clinicians and researchers a broader context for understanding brain injury and helping patients adjust. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dopant induced RTFM and enhancement of fluorescence efficiencies in spintronic ZnS:Ni nanoparticles

Diluted magnetic semiconducting (DMS) ZnS:Ni (Ni=0, 1, 3 and 5 at%) nanoparticles were synthesized by the refluxing technique at 80 °C. X-ray diffraction studies showed that undoped ZnS and Ni doped ZnS nanoparticles exhibited the expected zinc blende structure. X-ray photoelectron spectroscopy results revealed that the Ni ions existed in a +2 state in these nanoparticles. Reflectance measurements showed a decrease in band gap with increasing Ni concentration. Room temperature photoluminescence (PL) studies indicated that all the samples exhibited broad and asymmetric PL peaks covering a wide visible range. Gaussian fitting of PL data resulted in three deconvoluted peaks corresponding to blue and green emissions. Dramatic enhancement in fluorescence efficiency was observed in the doped ZnS nanoparticles indicating their possible applications in photoluminescent devices. Magnetic studies revealed that all the doped samples exhibited carrier mediated ferromagnetism at room temperature. Saturation magnetization (M_s) increased with increasing Ni content reaching a maximum for 3 at% Ni and decreased for samples of 5 at% Ni.     

Performance Evaluation of Relay Assisted Wireless Powered Network over Fluctuating Two Ray Fading Channel with Diversity Reception

Recently wireless powered networks have emerged as cutting-edge technology for addressing the power constraint issue of wireless devices (WD’s). This technology enables wireless nodes to harness power from the ambient radio frequency (RF) signal thus enhances the energy efficiency of the communication network and also improves the network longevity. The underlying principle of energy harvesting (EH) by wireless power transfer (WPT) has implications on system performance due to link distance and channel fading. To address the impact of channel fading on energy constraints WD’s this work explores the maximal ratio combining (MRC) diversity at the receiver node for the presented simultaneous wireless information and power transfer (SWIPT) model considering the energy constraint unmanned aerial vehicle (UAV) mounted amplify and forward (AF) relay. Assuming fluctuating two ray (FTR) fading scenario a novel analytical expression for the outage probability (OP) and symbol error rate (SER) for the presented system has been derived. As the FTR fading channel provides a generalized fading model and can significantly model millimeter wave band signals. Based on derived performance metrics this paper investigates the impact of variation on node positioning and EH time allocation factor on system outage probability (OP) and symbol error rate (SER) performance. Finally, the derived expression has been validated by comparing the results obtained from the Monte Carlo simulation.

     

Wireless powered communication network optimization using PSO-CS algorithm

Wireless Networks - Wireless powered communication network (WPCN) is a promising technique to resolve the power constraint issue faced by wireless nodes at the same time it also provides green and...     

Spray deposited Nb2O5 thin film electrodes for fabrication of dye sensitized solar cells

Nb₂O₅ thin film electrodes have been deposited on indium tin oxide substrates by spray pyrolysis technique. XRD analysis reveals tetragonal phase of the film. Reticulated micro-fibrous surface morphology has been observed by scanning electron microscopy and atomic force microscopy indicates closely packed crystallites. Film thickness found using a stylus profilometer is around 26 nm. Transmittance spectra show the film to be 70–80% transparent in the visible region. Direct, indirect band gap and phonon energy are also estimated. Cyclic voltammetry measurement indicate distinct anodic peak during negative potential of the scan due to Li extraction. A reversible colour change from transparent to grey has been observed. The photo-electrochemical characteristic of the dye sensitized solar cell is studied by recording the I-V characteristics of the unsealed type cell under illumination of 40 mW/cm² using a solar simulator.     

Structural characteristics,fluorescence quenching,and antioxidant activity of the arabinogalactan protein-rich fraction from senna (<Emphasis Type="Italic">Cassia angustifolia</Emphasis>) leaves

Senna (Cassia angustifolia) is widely used in Indian folk medicine for the prevention of various disorders. Herein, we have demonstrated that water extracted arabinogalactan protein (AGP) rich fraction possesses strong antioxidative activity. The AGP rich fraction was analyzed using chemical, chromatographic, and spectroscopic methods. Effect of water extracted polymers on bovine serum albumin spectrum was determined using excitation wavelength of 282 nm. The antioxidant capacity of this fraction was studied by ferric reducing antioxidant power (FRAP) and DPPH radical assays. This polymeric fraction, ≥88% of which gets precipitated with Yariv reagent, consisted mainly of (1→5)-/(1→3,5)-linked α-arabinosyl, (1→3)-/(1→3,6)-linked-galactosyl residues and terminal arabinofuranosyl residues. Its in vitro antioxidant capacity is comparable to that of standard antioxidants. Fluorescence quenching studies furnishes evidence for the interaction of the arabinogalactan protein with bovine serum albumin.