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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.

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

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. Source

Som A.,Allahabad University
Briefings in Bioinformatics

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. Source

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

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. Source

Sharma B.,Allahabad University
Neurobehavioral HIV Medicine

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. Source

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. Source

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