Showing papers by "Gaurav Sharma published in 2013"

Status of Foot-and-mouth Disease in India

Abstract: Foot-and-mouth disease (FMD) is endemic in India and causes severe economic loss. Status of FMD in the country for five fiscal years is presented. Outbreaks were more in number in 2007-2008 than 2010-2011. Three serotypes of FMD virus (O, A and Asia1) are prevalent. Serotype O was responsible for 80% of the confirmed outbreaks/cases, whereas Asia1 and A caused 12% and 8%, respectively. Geographical region-wise assessment indicated varying prevalence rate in different regions viz; 43% in Eastern region, 31.5% in Southern region, 11.6% in North-eastern region, 5% Central region, 4.4% Western region and 4% in Northern region. Highest number of outbreaks/cases was recorded in the month of September and lowest in June. Emergence and re-emergence of different genotypes/lineages within the serotypes were evident in real-time investigation carried out from time to time. Continues antigenic divergence in serotype A resulted in change in the vaccine strain in 2009. As on date, all genetic diversity within the serotypes is well tolerated by the vaccine strains. Unrestricted animal movements in the country play a major role in the spread of FMD.

Enhancement of power conversion efficiency of dye-sensitized solar cells by co-sensitization of zinc-porphyrin and thiocyanate-free ruthenium(II)-terpyridine dyes and graphene modified TiO2 photoanode

Abstract: A combination of a meso substituted zinc-porphyrin with two pyridyl groups and two benzoate groups at cis positions to each other (POR) with a mononuclear ruthenium(II) complex containing a 2,6-bis(1-methylbenzimidazol-2-yl)pyridine ligand and a carboxylic acid functionalized terpyridine ligand (SPS-G3) has been used as co-sensitizing system for the fabrication of dye-sensitized solar cells (DSSCs). The POR/SPS-G3 co-sensitized solar cell with a TiO2 photoanode displays enhanced short circuit current, open circuit voltage, and fill factor values (Jsc = 16.18 mA cm−2, Voc = 0.64 V, FF = 0.71, respectively), resulting in an overall power conversion efficiency (PCE) of 7.35%, which is superior to that for the DSSCs based on the individual dyes POR and SPS-G3. This is attributed to the improved light harvesting efficiency of the POR/SPS-G3 co-sensitizing system, which is evidenced by the incident photon-to-current efficiency (IPCE) spectrum of the co-sensitized solar cell. Further improvement of the PCE value of the co-sensitized solar cell (up to 8.15%) has been achieved by using a graphene modified TiO2 (G-TiO2) photoanode, instead of a pure TiO2 photoanode. Based on dark current measurements and electrochemical impedance spectra (EIS), the increased PCE value of the solar cell with the G-TiO2 photoanode can be attributed to suppression of charge recombination at the photoanode/dye/electrolyte interface and enhancement of electron transport in the photoanode. These results are in accordance with the longer electron lifetime exhibited by the G-TiO2 photoanode.

Cosensitization of dye sensitized solar cells with a thiocyanate free Ru dye and a metal free dye containing thienylfluorene conjugation

Abstract: A stepwise approach has been applied for the cosensitization of a thiocyanate free Ru sensitizer (SPS-01) with a metal free dye containing thienylfluorene conjugation (JD1) for dye sensitized solar cells (DSSCs). The cosensitized SPS-01 + JD1 based DSSC showed a significant enhancement in both the open circuit voltage (Voc) and the short circuit current (Jsc) relative to the individual single dye based DSSCs. The DSSC based on the SPS-01 + JD1 system yielded a Jsc of 15.38 mA cm−2, a Voc of 0.72 V, a fill factor (FF) of 0.76 and a power conversion efficiency (PCE) of 8.30%. This performance was superior to that of the DSSCs sensitized with the individual dyes SPS-01 (PCE = 5.98%) or JD1 (PCE = 4.76%) fabricated under the same conditions. Results show that the JD1 dye effectively overcomes the competitive light absorption by I3−/I− and also prevents dye aggregation and reduces the charge recombination. To understand the effects of the charge recombination of the injected electrons with I3− in the electrolyte, the dark current–voltage characteristics and electrochemical impedance spectra of the DSSCs sensitized with the SPS-01 and SPS-01+JD1 systems were measured. It was observed that the recombination of the electrons in the conduction band with I3− in the electrolyte in the DSSC sensitized with SPS-01 +JD1 was significantly reduced relative to the DSSC based on SPS-01.

A new porphyrin bearing a pyridinylethynyl group as sensitizer for dye sensitized solar cells

Abstract: A novel porphyrin dye extended at one meso -position via an pyridinylethynyl group acting as anchoring group and three phenyl COOMe groups was synthesized and used as sensitizer for the fabrication of dye sensitized solar cells (DSSCs). The overall power conversion efficiencies (PCE) of DSSCs based on this porphyrin dye as sensitizer with and without CDCA coadsorbant are 3.36% and 4.56%, respectively. To improve the PCE of DSSC, we have incorporated Ag nanoparticles into the nano-porous TiO 2 photoanode i.e. FTO/TiO 2 /Ag-NPs and found a enhancement up to 5.66%. The improved photovoltaic performance of the DSSCs with modified photoanode is attributed to the (i) the increased light harvesting efficiency due to the plasmon enhanced optical absorption induced by Ag nanoparticles, (ii) reduced back recombination process at TiO 2 /dye/electrolyte interface, (iii) improved electron lifetime, and (iv) formation of Schottky barrier at TiO 2 /NPs-Ag.

Per-Colorant-Channel Color Barcodes for Mobile Applications: An Interference Cancellation Framework

Abstract: We propose a color barcode framework for mobile phone applications by exploiting the spectral diversity afforded by the cyan (C), magenta (M), and yellow (Y) print colorant channels commonly used for color printing and the complementary red (R), green (G), and blue (B) channels, respectively, used for capturing color images. Specifically, we exploit this spectral diversity to realize a three-fold increase in the data rate by encoding independent data in the C, M, and Y print colorant channels and decoding the data from the complementary R, G, and B channels captured via a mobile phone camera. To mitigate the effect of cross-channel interference among the print-colorant and capture color channels, we develop an algorithm for interference cancellation based on a physically-motivated mathematical model for the print and capture processes. To estimate the model parameters required for cross-channel interference cancellation, we propose two alternative methodologies: a pilot block approach that uses suitable selections of colors for the synchronization blocks and an expectation maximization approach that estimates the parameters from regions encoding the data itself. We evaluate the performance of the proposed framework using specific implementations of the framework for two of the most commonly used barcodes in mobile applications, QR and Aztec codes. Experimental results show that the proposed framework successfully overcomes the impact of the color interference, providing a low bit error rate and a high decoding rate for each of the colorant channels when used with a corresponding error correction scheme.

Microwave induced KOH activation of guava peel carbon as an adsorbent for congo red dye removal from aqueous phase

Abstract: The adsorption capacity of activated carbon prepared from guava fruit peel waste has been studied for congo dye. The activation process is carried out under microwave radiations in the presence of KOH. The guava peel based activated carbon (GPAC) and unactivated carbon (GPUC) have been characterized using Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction. The comparative adsorption behavior of GPAC, GPUC and commercially activated carbon (CAC) has been studied for the congo red dye removal using batch adsorption experiments. The non-linear Langmuir and Frendulich isotherm models are used to stimulate the equilibrium data. The equilibrium data is represented by the Langmuir isotherm model. The kinetic model shows that pseudo second order kinetics has best fit to the experimental data (R 2 >0.90). Thermodynamic studies conclude that adsorption process is spontaneous and endothermic in nature. GPAC has emerged as efficient adsorbent for congo dye as compared to GPUC and CAC. Further, desorption studies show that 35.74 % of metal ions can be recovered by desorption in first cycle and adsorbent can be reused.

Clinical Implications of Referral Bias in the Diagnostic Performance of Exercise Testing for Coronary Artery Disease

Abstract: Background Exercise testing with echocardiography or myocardial perfusion imaging is widely used to risk-stratify patients with suspected coronary artery disease. However, reports of diagnostic performance rarely adjust for referral bias, and this practice may adversely influence patient care. Therefore, we evaluated the potential impact of referral bias on diagnostic effectiveness and clinical decision-making. Methods and Results Searching PubMed and EMBASE (1990–2012), 2 investigators independently evaluated eligibility and abstracted data on study characteristics and referral patterns. Diagnostic performance reported in 4 previously published meta-analyses of exercise echocardiography and myocardial perfusion imaging was adjusted using pooled referral rates and Bayesian methods. Twenty-one studies reported referral patterns in 49 006 patients (mean age 60.7 years, 39.6% women, and 0.8% prior history of myocardial infarction). Catheterization referral rates after normal and abnormal exercise tests were 4.0% (95% CI, 2.9% to 5.0%) and 42.5% (36.2% to 48.9%), respectively, with odds ratio for referral after an abnormal test of 14.6 (10.7 to 19.9). After adjustment for referral, exercise echocardiography sensitivity fell from 84% (80% to 89%) to 34% (27% to 41%), and specificity rose from 77% (69% to 86%) to 99% (99% to 100%). Similarly, exercise myocardial perfusion imaging sensitivity fell from 85% (81% to 88%) to 38% (31% to 44%), and specificity rose from 69% (61% to 78%) to 99% (99% to 100%). Summary receiver operating curve analysis demonstrated only modest changes in overall discriminatory power but adjusting for referral increased positive-predictive value and reduced negative-predictive value. Conclusions Exercise echocardiography and myocardial perfusion imaging are considerably less sensitive and more specific for coronary artery disease after adjustment for referral. Given these findings, future work should assess the comparative ability of these and other tests to rule-in versus rule-out coronary artery disease.

Biomedical applications of nano-antioxidant

Abstract: For centuries now, antioxidants have been known to provide better health by neutralizing the free radicals which are continuously produced in the human body. In normal circumstances, self-antioxidant defense system of the human body is capable of quantitatively managing the free radicals. However, in certain cases, which are at the threshold of developing diseases like diabetes and Alzheimer's, the human body calls for an external source of antioxidants. Since orally delivered antioxidants are easily destroyed by acids and enzymes present in the human system, only a small portion of what is consumed actually gets absorbed. Hence, there is a recognized and urgent need to develop effective methods for efficiently delivering antioxidants to the required sites. This chapter provides an in-depth overview and analysis of two such methods and processes-nano-encapsulation and nano-dendrimers. Among the various nanoscale delivery mechanisms, nano-encapsulation has emerged as a key and efficient delivery process. Designed as a spongelike polymer, nano-encapsulated antioxidants provide a protective vehicle which keeps antioxidants from being destroyed in the human gut and ensures their better absorption in the digestive tract. In fact, the nano-capsules bind themselves to the intestinal walls and pour antioxidants directly into the intestinal cells, which allow them to be absorbed directly into the blood stream. Another distinguished and popular mode for delivering antioxidants is that of nano-polymers known as dendrimers. Dendrimers involve multiple branches and sub-branches of atoms radiating out from a central core. Dendrimers afford a high level of control over their architectural design, including their size, shape, branching length or density, and surface functionality. Such flexibility makes these nanostructures ideal carriers in biomedical applications such as drug delivery, gene transfection, and imaging. Antioxidant dendrimers, made out of numerous units of antioxidants connected with each other in a branched fashion, provide numerous possible sites to couple with an active species and have enhanced free radicals scavenging potency. These dendrimer chains are biocompatible, biodegradable with nontoxic degradation products, and well suited for targeted drug delivery and other biomedical applications. Recent successes in simplifying and optimizing the synthesis of dendrimers, such as the "lego" and "click" approaches, provide a large variety of structures while at the same time reducing the cost of their production. The use of these highly branched, nanometer-sized, polymeric materials as nano-antioxidants for prevention and treatment of human diseases, associated with oxidative stress, is of immense public health relevance globally.

Classification of Symmetric Key Management Schemes for Wireless Sensor Networks

Abstract: WSN is the collection of thousands of tiny sensor nodes, which have the capability of sensing, computing and transmitting the information in the network. Due to the low circuit design, it has some resource constraints but efficient to carry the information through wireless communication. But the exchange of information in a secure manner is critical in WSN. There are many techniques developed in recent years for the security purposes, one of the area is the key management. Key management is the challenging issue in sensor networks. In this paper we present the key management techniques for wireless sensor networks and classification has been presented based on the encryption techniques.

Application of solution processable squaraine dyes as electron donors for organic bulk-heterojunction solar cells.

Abstract: New low bandgap small molecules based on a squaraine (SQ) chromophore, bis[4-(2,6-di-tert-butyl)vinylpyrylium]squaraine (TBU-SQ), bis[2,6-di-tert-butyl-4-(prop-1-en-2-yl)pyrylium]squaraine (MeTBU-SQ) and bis[4-(but-1-en-2-yl)-2,6-di-tert-butylpyrylium]squaraine (EtTBU-SQ), were synthesized and used as electron donors along with PC70BM for their application in solution processed organic bulk-heterojunction (OBHJ) solar cell (SC). The long wavelength of these SQ dyes are located in between 650–750 nm in thin films and the optical bandgaps are about 1.64, 1.52 and 1.48 eV, respectively. The electrochemical properties of these SQ dyes indicate that they are well suited for the fabrication of OBHJSCs as electron donors along with fullerene derivatives as electron acceptors. The OBHJ photovoltaic (PV) devices fabricated with the blend of TBU-SQ:PC70BM, MeTBU-SQ:PC70BM and EtTBU-SQ:PC70BM cast from chloroform (CF) solvent exhibited a power conversion efficiency (PCE) of 1.71%, 2.15%, and 1.89%, respectively. The PCE of the OBHJSCs based on MeTBU-SQ:PC70BM blends cast from DIO–THF (DIO = 1,8-diiodooctane) additive solvent and cast from DIO–THF with subsequent thermal annealing have been further improved up to 2.73% and 3.14%, respectively. This enhancement in the PCE is attributed to the improvement in the crystalline nature of the blend and more balanced charge transport resulting from the higher hole mobility. All these results have been supported by the quantum chemical calculations.

2,6-Bis(1-methylbenzimidazol-2-yl)pyridine: a new ancillary ligand for efficient thiocyanate-free ruthenium sensitizer in dye-sensitized solar cell applications.

Abstract: We have designed and synthesized a new thiocyante-free ruthenium complex containing 2,6-bis(1-methylbenzimidazol-2-yl)pyridine, coded as SPS-G3, and it has been used as an efficient photosensitizer for dye-sensitized solar cells (DSSCs). Upon sensitization of SPS-G3 on nanocrystalline TiO2 film, the DSSC test cell yielded a large short-circuit photocurrent (16.15 mA cm–2), an open circuit voltage of 0.52 V, and a fill factor (FF) of 0.72, resulting in an overall power conversion efficiency (PCE) of 6.04% under simulated AM 1.5 solar irradiation (100 mW cm–2). DSSCs were prepared by adding various concentrations of multiwall carbon nanotubes (MWCNTs) (up to 0.5 wt %) into the TiO2 nanoparticles. Optimization of MWCNT concentration (0.3 wt %) lead to PCE values as high as 7.76%, while the test cells employing pure TiO2 photoanode obtained an efficiency of 6.04%. The results indicate that the PCE of MWCNTs/TiO2 composite DSSCs are dependent on the quantity of MWCNTs loading on the photoanodes. A small amount...

Diarylmethanofullerene: Efficient Polymer Solar Cells with Low-Band- Gap Copolymer

Abstract: The photovoltaic performance of the polymer bulk heterojunction solar cells based on the low-band-gap D–A copolymer P as donor and modified fullerene (modi-PC60BM) as acceptor was in. We have achieved power conversion efficiency (PCE) of ∼2.35% for a polymer solar cell with modi-PC60BM as an electron acceptor in bulk heterojunction active layer, which is higher than that for PC60BM counterpart (1.50%). The increase in the PCE has been attributed to the increase in absorption in visible and higher LUMO level of modi-PC60BM, resulting in enhancement in Jsc and Voc, respectively. In the device fabrications, we studied the effect of the solvent additive and modified PEDOT:PSS as a hole transport layer. The PCE of the polymer solar cell was improved up to 3.63% when the P:modi-PC60BM active layer was processed with the addition of CN as an additive in the THF solution (CN/THF), which is mainly attributed to more balanced charge transport due to the increased crystallinity of P in the blend. The PCE of polymer ...

Hypoglycemic and Hepatoprotective Effects of Processed Aloe vera Gel in a Mice Model of Alloxan Induced Diabetes Mellitus

Abstract: Diabetes mellitus is a heterogeneous disease characterized by altered cellular metabolism. So many traditional herbs are being used by diabetic patients to control this disease. The aim of this study was to investigate the effects of aqueous extract of aloe vera leaves on hypoglycemic activity and hepatoprotective effects after alloxan injection in Swiss albino mice. In this study, aqueous leaf extract of aloe vera was carried out. Diabetes was induced in mice by alloxan monohydrate at dose of 150 mg/kg body weight injected intraperitoneally. Also alloxanized induced mice were administered with 300 and 500 mg/kg body weight orally daily of extract for a period of 21 days. At the end of the administration period, the mice were anaesthesized and dissect for the collection of blood and liver tissues. In diabetic mice, the SGOT, SGPT and bilirubin level as well as serum glucose levels were significantly increased (p<0.05) in comparison with the control groups. Diabetic mice group treated by extract at the dose of 300 and 500 mg/kg body weight orally significantly (p<0.05) reduced and normalised these biochemical parameters compared with alloxan induced diabetic group. Histopathological study also did show adverse alternation in the morphological architecture of the liver tissue. The results suggested that aqueous extract of aloe vera leaves possesses protective effect against alloxan induced diabetic mice.

Sensitivity Modulation of Surface Plasmon Resonance Sensor Configurations in Optical Fiber Waveguide

Abstract: The re∞ectivity of three layer and four layer optical flber based surface plasmon resonance sensors having silica material substrate and chalcogenide material substrate is plotted and studied. Using the transfer matrix method, the re∞ection coe-cient for p- polarized incident lights at various wavelengths is obtained. It is observed that the sensitivity, detection accuracy and quality parameters of the sensor having silica substrates are much larger than the chalcogenide substrates. These parameters can also be increased by introducing an additional thin layer of silica/chalcogenide material on the metallic surface. Also, these sensor parameters are highly afiected by the thickness of the additional thin layer.

Ion-dipole induced interaction between cationic gemini/TTAB and nonionic (Tween) surfactants: interfacial and microstructural phenomena

Abstract: The present work is focused at studying the interactions between alkanediyl-α, ω-bis(tetradecyldimethylammonium) dibromide type cationic gemini surfactants, 14-s-14 (s = 4, 5, and 6) and conventional nonionic Tweens (Tween 20, Tween 40, Tween 60, and Tween 80) and to attain a comparison with their monomeric counterpart tetradecyltrimethylammonium bromide (TTAB). The critical micelle concentrations (cmc) of mixtures of varying compositions have been evaluated using surface tension measurements. The molecular interaction parameters (β) at the monolayer air–water interface and in bulk, standard free energy of micellization (ΔG°mic), excess free energy of mixing (ΔG°ex), Gibbs energy of adsorption (ΔG°ad), and activity coefficients for the constituents in the mixtures (fi) were evaluated by employing the Clint, Rubingh, and Rosen approaches. All the parameters indicate synergism in the systems and effective involvement of the nonionic (Tween) component in the mixtures. Micelle aggregation numbers (Nagg), obtained using steady-state fluorescence quenching technique, also indicate enrichment of mixed micelles with Tweens. The micropolarity, dielectric constant and Stern–Volmer binding constants (Ksv) of the mixed systems have also been evaluated from the fluorescence data. Three-dimensional fluorescence spectroscopy has also been performed for better understanding of the quenching experiments.

Stature estimation from the dimensions of foot in males

Abstract: Stature estimation is a commonly used parameter in identification searched by medico-legal experts and forensic anthropologists. Examination of footprints provides important evidence in a crime scene investigation and helps in estimation of stature of a criminal. The present study examines the relationship between stature and foot dimensions among a diverse population group. To estimate stature; measurements of foot length (FL), foot breadth (FB) were used in this study. Measurements were obtained from 250 volunteers. The best correlation value were detected in foot dimensions as FL variable for males r=0.575. Lengths measurements belong to foot dimensions were more useful parameters than breadth measurements of those in stature estimation.

Profile of Medico-legal Cases in Casualty of a Rural Medical College of Haryana

Abstract: Apex court of our country has made saving life of patient in emergency supreme duty of doctor. However, medico-legal cases mandates exhaustive documentation mandatory after the treatment is over. Medico legal cases are handled in casualty by first Contact doctor. Contact doctor is generally a MBBS doctor and he seeks many expert opinions in a single report. So, the case then has to go to different departments for expert opinion. Present study was conducted in Bhagat Phool Singh Govt. Medical College for Women (BPS GMC), Khanpur Kalan, Sonepat from 1st September 2011 to 1st November 2012. In this study predominant sex was male and age group was 20–40 years. Bulk of the cases in the study was road side accidents and poisoning. In all the cases the contact doctors sought expert. Profiling helps in knowing the burden of medico-legal cases on different departments.

An Improved Forward Secure Elliptic Curve Signcryption Key Management Scheme for Wireless Sensor Networks

Abstract: The concept of forward secrecy is extended to wireless sensor networks where it is frequent that nodes run out of energy and new nodes join the network However it should not be able to retrieve the previous session key or some crucial information In 2011 Hagras et al proposed a key management scheme for heterogeneous wireless sensor networks, which satisfies confidentiality, authentication, integrity and unforgetability but lacks forward secrecy In this paper, the shortcomings of the victim scheme has been extricated and repaired with the help of Elliptic Curve Discrete logarithm problem (ECDLP) An elliptic curve based signcryption key management scheme has been proposed which includes forward secrecy

A Novel Approach for Efficient SVM Classification with Histogram Intersection Kernel.

Abstract: The kernel trick - commonly used in machine learning and computer vision - enables learning of non-linear decision functions without having to explicitly map the original data to a high dimensional space. However, at test time, it requires evaluating the kernel with each one of the support vectors, which is time consuming. In this paper, we propose a novel approach for learning non-linear SVM corresponding to the histogram intersection kernel without using the kernel trick. We formulate the exact non-linear problem in the original space and show how to perform classification directly in this space. The learnt classifier incorporates non-linearity while maintaining O(d) testing complexity (for d-dimensional input space), compared to O(d Nsv) when using the kernel trick. We show that the SVM problem with histogram intersection kernel is quasi-convex in input space and outline an iterative algorithm to solve it. The proposed approach has been validated in experiments where it is compared with other linear SVM-based methods, showing that the proposed method achieves similar or better performance at lower computational and memory costs.

Formulation and Characterization of Drug Loaded Niosomal Gel for Anti-Inflammatory Activity

Abstract: The main aim of the present research was to encapsulate mefenamic acid in niosomes andincorporate the prepared niosomes in the carbopol gel base for sustained therapeutic action. Mefenamic acid loaded niosomes were prepared by thin film hydration technique and evaluated for entrapment efficiency, vesicular size and zeta potential. The entrapment efficiency of the prepared niosomes was found to increase with decreasing the HLB values of surfactants and vesicle size was found to increase with increasing the cholesterol concentration. Niosomal vesicles with good entrapment efficiencies were incorporated in carbopol gel base to form the niosomal gel. The prepared niosomal gel was evaluated for pH, viscosity, spreadability, extrudability and skin permeation study across the rat skin. The results of permeation study revealed that the gel formulated with span 60 niosomes sustained the drug release for 12h. Further the in vivo study showed the good inhibition of inflammation by the gel prepared with span 60 niosomes. Keywords—Mefenamic acid, niosomal gel, nonionic surfactants, sustained release.

On the Security of Certificateless Signature Schemes

Abstract: Wireless Sensor Network (WSN) has proved its presence in various real time applications and hence the security of such embedded devices is a vital issue. Certificateless cryptography is one of the recent paradigms to provide security. Certificateless public key cryptography (CL-PKC) deals effectively with the twin issues of certificate management in traditional public key cryptography and key escrow problem in identity-based cryptography. CL-PKC has attracted special attention in the field of information security as it has opened new avenues for improvement in the present security architecture. Recently, Tsai et al. proposed an improved certificateless signature scheme without pairing and claimed that their new construction is secure against different kinds of attacks. In this paper, we present a security analysis of their scheme and our results show that scheme does not have resistance against malicious-KGC attack. In addition, we have found some security flaws in the certificateless signature scheme of Fan et al. and proved the scheme vulnerable to Strong Type I attack.