Allahabad, India

Allahabad University
Allahabad, India

The University of Allahabad, informally known also as Allahabad University is a public central university located in Allahabad, Uttar Pradesh, India. Established on September 23, 1887, it is the fourth oldest University in India. Its origins lie in the Muir Central College, named after Lt. Governor of North-Western Provinces, Sir William Muir in 1876, who suggested the idea of a Central University at Allahabad, which later evolved to the present university. At one point it was called the "Oxford of the East", and on 24 June 2005 its Central University status was restored through the 'University Allahabad Act, 2005', of the Parliament of India. Wikipedia.

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Tiwari V.K.,Allahabad University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We are computing the modifications for the scalar and pseudoscalar meson masses and mixing angles due to the proper accounting of fermionic vacuum fluctuation in the framework of the generalized 2+1 flavor quark meson model and the Polyakov loop augmented quark meson model (PQM). The renormalized contribution of the divergent fermionic vacuum fluctuation at one loop level makes these models effective QCD-like models. It has been explicitly shown that analytical expressions for the model parameters, meson masses, and mixing angles do not depend on any arbitrary renormalization scale. We have investigated how the incorporation of fermionic vacuum fluctuation in quark meson and PQM models qualitatively and quantitatively affects the convergence in the masses of the chiral partners in pseudoscalar (π,η,η′,K) and scalar (σ,a0,f0,κ) meson nonets as the temperature is varied on the reduced temperature scale. Comparison of present results in the quark meson model with vacuum term and the PQM model with vacuum term with the already existing calculations in the bare 2+1 quark meson and PQM models shows that the restoration of chiral symmetry becomes smoother due to the influence of the fermionic vacuum term. We find that the melting of the strange condensate registers a significant increase in the presence of the fermionic vacuum term and its highest melting is found in the PQM model with vacuum term. The role of the UA(1) anomaly in determining the isoscalar masses and mixing angles for the pseudoscalar (η and η′) and scalar (σ and f0) meson complex has also been significantly modified due to the fermionic vacuum correction. In its influence, the interplay of chiral symmetry restoration and the setting up of the UA(1) restoration trends have also been shown to be significantly modified. © 2013 American Physical Society.

Sinha P.,Allahabad University | Pandey A.,Allahabad University
International Journal of Hydrogen Energy | Year: 2011

Hydrogen, the most abundant and lightest element in the universe, has enormous potential as a future energy. High conversion efficiency, recyclability and nonpolluting nature of hydrogen make it the fuel of future. Various microorganisms are explored for producing hydrogen by exploiting variety of biological organic substrates. The target is the genetic improvement of the organism or the biochemical pathway required for biohydrogen production and devising path even better in comparison to the other production methods. The present review discusses different methods of biohydrogen production specifically by the fermentative route, physical factors affecting its production and other aspects for enhancement in the yield of hydrogen production. Metabolic engineering strategies for enhancement in hydrogen production to overcome different limitation have been also summarized. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights.

Som A.,Allahabad University
Briefings in Bioinformatics | Year: 2014

Phylogenetic analysis is used to recover the evolutionary history of species, genes or proteins.Understanding phylogenetic relationships between organisms is a prerequisite of almost any evolutionary study, as contemporary species all share a common history through their ancestry. Moreover, it is important because of its wide applications that include understanding genome organization, epidemiological investigations, predicting protein functions, and deciding the genes to be analyzed in comparative studies. Despite immense progress in recent years, phylogenetic reconstruction involves many challenges that create uncertainty with respect to the true evolutionary relationships of the species or genes analyzed. One of the most notable difficulties is the widespread occurrence of incongruence among methods and also among individual genes or different genomic regions. Presence of widespread incongruence inhibits successful revealing of evolutionary relationships and applications of phylogenetic analysis. In this article, I concisely review the effect of various factors that cause incongruence in molecular phylogenies, the advances in the field that resolved some factors, and explore unresolved factors that cause incongruence along with possible ways for tackling them. © The Author 2014.

Singh R.,Allahabad University | Khare A.,Allahabad University
Information Fusion | Year: 2014

Multimodal medical image fusion is an important task for the retrieval of complementary information from medical images. Shift sensitivity, lack of phase information and poor directionality of real valued wavelet transforms motivated us to use complex wavelet transform for fusion. We have used Daubechies complex wavelet transform (DCxWT) for image fusion which is approximately shift invariant and provides phase information. In the present work, we have proposed a new multimodal medical image fusion using DCxWT at multiple levels which is based on multiresolution principle. The proposed method fuses the complex wavelet coefficients of source images using maximum selection rule. Experiments have been performed over three different sets of multimodal medical images. The proposed fusion method is visually and quantitatively compared with wavelet domain (Dual tree complex wavelet transform (DTCWT), Lifting wavelet transform (LWT), Multiwavelet transform (MWT), Stationary wavelet transform (SWT)) and spatial domain (Principal component analysis (PCA), linear and sharp) image fusion methods. The proposed method is further compared with Contourlet transform (CT) and Nonsubsampled contourlet transform (NSCT) based image fusion methods. For comparison of the proposed method, we have used five fusion metrics, namely entropy, edge strength, standard deviation, fusion factor and fusion symmetry. Comparison results prove that performance of the proposed fusion method is better than any of the above existing fusion methods. Robustness of the proposed method is tested against Gaussian, salt & pepper and speckle noise and the plots of fusion metrics for different noise cases established the superiority of the proposed fusion method. © 2013 Elsevier B.V. All rights reserved.

Sharma B.,Allahabad University
Neurobehavioral HIV Medicine | Year: 2011

Antihuman immunodeficiency virus type 1 (anti-HIV-1) medications have helped millions of HIV-1-infected people lead longer and healthier lives. The goal of HIV-1 treatment is to reduce the number of virions in the body of infected individuals and to prevent rapid destruction of CD4+ T-lymphocyte cells, thus protecting the immune system. Most of the anti-HIV-1 drugs in practice are designed using viral reverse transcriptase (HIV-1RT), protease, and integrase as targets. These drugs that inhibit the activities of HIV-1RT, viral protease, and integrase are therefore known as anti-HIV-1RT, antiprotease, and anti-integrase molecules, respectively. The US Food and Drug Administration has approved 22 anti-HIV-1/acquired immunodeficiency syndrome (AIDS) drugs for clinical use by HIV-1-infected individuals and AIDS patients. Among the drugs, most of the nucleoside analogs (excluding two isomers of 3TC, (-)3TC and (+)3TC, which are shown to be less toxic in cell culture) exhibit clinical complications that pose a threat to chemotherapy. The toxicity of these molecules arises due to their negative impact on the activities of human mitochondrial chromosomal DNA polymerases (α, δ, β, and ε) in general and DNA polymerase γ in particular. Other anti-HIV-1 regimens are also reported to cause toxicity. The range of toxicity extends from mild to life-threatening levels. The prolonged use of zidovudine (3'-azido-3'-deoxythymidine [AZT] or Retrovir), which was first approved in 1987 as a nucleoside analog reverse transcriptase inhibitor, has been reported to cause severe hematologic toxicity, including severe anemia, granulocytopenia, and symptomatic myopathy. Many other drugs that are often used in combination with AZT have similar toxicities. The newer antiretrovirals (ARVs), such as 2',3'-dideoxycytidine, 2',3'-dideoxyinosine, and 2',3'-dideoxy-2',3'-didehydrothymidine, which exhibit analogous mechanisms of action and similar toxicities to AZT, have not been studied extensively. Acyclovir and gancyclovir can cause severe nausea and vomiting. Some of these ARVs when taken during pregnancy may generate teratogenic effects. Similarly, use of antiproteases in highly active ARV therapy causes hepatotoxicity, which poses a severe risk to the patients. In addition, application of fusion inhibitors and anti-integrases induces strong side effects in HIV-1-infected or AIDS patients. The present review illustrates a comprehensive analysis of the existing literature on the toxicity of anti-HIV-1/AIDS drugs, their mechanisms of action, and possible management strategies to combat this problem. © 2011 Sharma, publisher and licensee Dove Medical Press Ltd.

Kumar S.,Allahabad University | Pandey A.K.,Allahabad University
The Scientific World Journal | Year: 2013

There has been increasing interest in the research on flavonoids from plant sources because of their versatile health benefits reported in various epidemiological studies. Since flavonoids are directly associated with human dietary ingredients and health, there is need to evaluate structure and function relationship. The bioavailability, metabolism, and biological activity of flavonoids depend upon the configuration, total number of hydroxyl groups, and substitution of functional groups about their nuclear structure. Fruits and vegetables are the main dietary sources of flavonoids for humans, along with tea and wine. Most recent researches have focused on the health aspects of flavonoids for humans. Many flavonoids are shown to have antioxidative activity, free radical scavenging capacity, coronary heart disease prevention, hepatoprotective, anti-inflammatory, and anticancer activities, while some flavonoids exhibit potential antiviral activities. In plant systems, flavonoids help in combating oxidative stress and act as growth regulators. For pharmaceutical purposes cost-effective bulk production of different types of flavonoids has been made possible with the help of microbial biotechnology. This review highlights the structural features of flavonoids, their beneficial roles in human health, and significance in plants as well as their microbial production. © 2013 Shashank Kumar and Abhay K. Pandey.

Tiwari V.K.,Allahabad University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

The critical end point (CEP) and the critical behavior in its vicinity have been explored in the two-flavor effective chiral models with and without the presence of an effective Polyakov loop potential. The tricritical point (TCP) in the massless chiral limit has been located on the phase diagram in the μ and T plane for the Polyakov loop-extended quark-meson model (PQM) and the pure quark-meson model, which become effective quantum chromodynamics (QCD)-like models due to the proper accounting of fermionic vacuum loop contributions in the effective potential. The proximity of the TCP to the QCD critical end point (CEP) has been quantified in the phase diagram. The critical region around the CEP has been obtained in both the presence and absence of fermionic vacuum-loop contributions in the effective potentials of the PQM and quark-meson models. The contours of appropriately normalized constant quark number susceptibility and scalar susceptibility have been plotted around the CEP in different model scenarios. These contours determine the shape of the critical region and facilitate comparisons between different models such that the influence of the fermionic vacuum term and the Polyakov loop potential on the critical behavior around the CEP can be ascertained in qualitative as well as quantitative terms. Critical exponents resulting from the divergence of quark number susceptibility at the CEP have been calculated and compared with those in different model scenarios. The possible influence of the TCP on the critical behavior around the CEP has also been discussed. The temperature variation of σ and π meson masses at μ=0, μ=μ CEP, and μ>μ CEP has been shown and compared with that seen in different model scenarios and the emerging mass degeneration trend in the σ and π meson mass variations has been inferred as the chiral-symmetry restoration takes place at higher temperatures. © 2012 American Physical Society.

Gupta U.S.,Allahabad University | Tiwari V.K.,Allahabad University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We have considered the contribution of fermionic vacuum loop in the effective potential of Polyakov loop extended quark-meson model (PQM) for the two-quark flavor case and explored the phase structure and thermodynamics of the resulting PQMVT model (Polyakov-quark-meson model with vacuum term) in detail at nonzero as well as zero chemical potential. The temperature variations of order parameters and their derivatives have been calculated and the phase diagram together with the location of critical end point (CEP) has been obtained in μ, and T plane in both the models PQMVT and PQM. The PQMVT model analysis has been compared with the calculations in PQM model in order to bring out the effect of fermionic vacuum term on the physical observables. The sensitivity of the phase structure and location of the CEP to the choice of Polyakov loop potential and sigma meson mass value has also been explored in the PQMVT model. We notice that the CEP which is located near the temperature axis at (μ=81MeV, T=167MeV) in the PQM model gets shifted close to the chemical potential axis at (μ CEP=294.7, T CEP=84.0MeV) in the PQMVT model calculations of the phase diagram. Since it emerges from a background of second-order transition in the chiral limit of massless quarks, the crossover occurring at μ=0 in PQMVT model for the realistic case of explicitly broken chiral symmetry, has been identified as quite a soft and smooth transition. We have presented and compared the results for temperature variations of thermodynamic observables at zero and different nonzero quark chemical potentials. It is noticed that the presence of fermionic vacuum term in the effective potential leads to a smoother and slower temperature variation of thermodynamic quantities. © 2012 American Physical Society.

Singh P.K.,Allahabad University
Journal of Agricultural and Food Chemistry | Year: 2012

Reaction of potassium 1H-1,2,4-triazole-3-selenolate (I) with acetylated ribose/deoxyribose (IIa,b) in the presence of montmorillonite K 10 as a solid adsorbent furnished potassium 1-acetylated ribosyl/deoxyribosyl-1H-1,2,4- triazole-3-selenolate (IIIa,b) with excellent yield under microwave irradiation in solvent-free conditions. This eliminates a series of complex isolation procedures and often minimizes the use of a large amount of expensive, toxic, and hazardous solvents after each step. This procedure reduces reaction time and cost and enhances yield. Reaction of compound (IIIa,b) with substituted/unsubstituted aryl diazonium chloride (IVa-e) at 0-5 °C gave pure 3-(substituted/unsubstituted phenyl selanyl)-1-acetylribosyl/deoxyribosyl- 1H-1,2,4-triazole (Va-j). Oxidation of compound (Va-j) with oxone followed by alkaline hydrolysis furnished quantitatively and analytically pure 3-(substituted/unsubstituted phenylselenonyl)-1-ribosyl/deoxyribosyl-1H-1,2,4- triazole (VIIa-j). Compounds VIa-j and VIIa-j were evaluated in vitro for their fungitoxicities against Fusarium oxysporum and Penicillium citrinum. All the compounds were found to be antifungal active. Some of the compounds displayed activities comparable with that of the commercial fungicide Dithane M-45 and griseofulvin. Structure-activity relationships for the screened compounds were discussed. The fact that both of these fungi have developed resistance to several fungicide groups made them optimal candidates as target organisms for ongoing research about the potential application of 1,2,4-triazole and analogue compounds as reduced-risk fungicides. © 2012 American Chemical Society.

Sharma B.,Allahabad University
Current HIV Research | Year: 2014

Oxidative stress, defined as the imbalance between the oxidant and antioxidant systems, is thought to be associated with the progression of human immunodeficiency virus (HIV) infection. It has been observed that perturbations in antioxidant defense systems, and consequently redox imbalance, are present in many tissues of HIV-infected patients. Existing evidences suggest that oxidative stress may contribute to different stages of viral life cycle including viral replication and its consequences such as inflammatory response and decreased immune cell proliferation. The level of production of free radical species in HIV-1 infected individuals receiving antiretrovirals (ART) including highly active antiretroviral therapy (HAART) was reported to be higher than those who harbor HIV-1 infection without receiving any treatment or normal and healthy subjects. These observations suggest that the HIV-1 infection alone or in combination with introduction of ARV/HAART may induce oxidative stress and further augment HIV-1 pathogenesis. HIV-1 infection and the treatment with antiretrovirals have been found to cause antioxidant enzyme dysfunction in monocytes and central spinal fluid (CSF) leading to cognitive impairment in women. However, the exogenous application of some natural plant products or recent synthetic antioxidants might be useful in scavenging the free radicals. It is expected that their application as an additional strategy may facilitate ARV therapy or HAART for the effective treatment of HIV-1 infected persons or AIDS patients. This review offers a perspective on the current account of oxidative stress in HIV-1 infected individuals and its possible amelioration using suitable antioxidants, plant products and herbal preparations. © 2014 Bentham Science Publisher.

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