Vignan University

About: Vignan University is a education organization based out in Guntur, Andhra Pradesh, India. It is known for research contribution in the topics: Computer science & Control theory. The organization has 1138 authors who have published 1381 publications receiving 7798 citations.

Experimental evidences of methanolic extraction of Cressa cretica Linn. on alloxan induced hyperglycemic Wistar rats

Abstract: Summary In the present study, the physico-metabolic parameters measured were: serum insulin, serum lipid profile, serum biomarker enzymes and anti-oxidant enzymes, total cholesterol, HDL cholesterol, triglycerides, LDL cholesterol, VLDL cholesterol, total proteins, alanine transaminase (ALT), aspartate transaminase (AST), creatinine, insulin assay (RIA), for in vivo anti-oxidant activity of MECC was measured in liver tissue homogenate (LTH) by malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD) enzymes and histopathological examination of pancreas were also observed. Previously, the methonolic extract of Cressa cretica Linn. effect on alloxan induced hyperglycemic Wistar rats was proved by taking the parameters like body weight, blood glucose, glycogen content in liver and muscle. Oral administration of MECC (200 mg/kg, 400 mg/kg) for 28 days exhibited a significant reduction in blood glucose, serum ALT, AST, CR, lipid profile and hepatic MDA levels. The improvement of hepatic enzymes such as GSH, serum TP, HDL, insulin levels were also observed. The results of this work also suggest that MECC may possess anti-hyperglycemic and anti-oxidant property.

Heat Transfer to Peristaltic Transport in a Vertical Porous Tube

Abstract: Peristaltic transport of a Newtonian fluid, with heat transfer, in a vertical porous axisymmetric tube under long-wavelength approximation is considered. Closed-form solution is obtained as an asymptotic expansion in terms of porosity and free convection parameters. Expressions, for velocity, temperature, coefficient of heat transfer and pressure–flow relationship at the boundary wall of the tube, are derived. It is observed that pressure drop increases as amplitude ratio increases. Further, it has been observed that for some specific values of different parameters under consideration, the mean flux significantly increases by about 8–10% as Grashof number increases from 1 to 2. This relates to optimization of heat transfer in certain processes.

Expression, purification, and characterization of pyruvate kinase from Mycobacterium tuberculosis: A key allosteric regulatory enzyme.

Abstract: Background: The current research aims to isolate pyruvate kinase (Pyk) gene from Mycobacterium tuberculosis and expression of the gene (Rv1617) to obtain a purified enzyme. The enzyme activity and secondary structural features were assessed through biochemical assays and circular dichroism (CD) spectroscopy, respectively. Methods: The Pyk-encoding gene from the complete genome of M. tuberculosis was cloned, sequenced, and expressed in Escherichia coli BL21 (DE3). The enzyme was purified by nickel-nitrilotriacetic acid affinity chromatography and enzyme activity was determined by a lactose dehydrogenase-coupled assay system. Further, far ultraviolet CD spectra of the enzyme and the substrate bound enzyme were analyzed using a Jasco J712 spectrophotometer. Results: A single protein with an approximate molecular mass of 54 kDa was purified and a specific activity of 5.31 units/mg was determined from purified M. tuberculosis Pyk. The activity of the enzyme indicating a protein is defined by separate domain for each catalytic function. The secondary structure analysis of CD spectra of the recombinant Pyk has revealed a content of 17% α-helix, 34% β-sheet, and 49% turns in the enzyme. Conclusion: The growing evidence has impacted M. tuberculosis central carbon metabolism as a key determinant of the survival and pathogenicity in the host. The purified Pyk was observed to have increased enzyme activity in all steps of purification. Retention of Pyk activity indicates a possible catalytic role for the lower part of the glycolytic pathway. The overall results of the spectra obtained from the CD suggest that the substrate phosphoenolpyruvate and adenosine diphosphate binding to the enzyme can cause conformational changes resulting in the exposure or shielding of residues susceptible to modification.

Multi-Layered Security Model for Hadoop Environment: Security Model for Hadoop

Abstract: In this article, a novel security model for the Hadoop environment has been developed to enhance security credentials of handheld systems. The proposed system deals with enabling Hadoop security in terms of a dataset and a user which is willing to access the content inside the Hadoop system. It deals with security in terms of three different features: encryption, confidentiality and authentication. The significance of the proposed model is it provides protection against malicious intent which allows only valid content into the Big data system; it enables authenticated users and people to enter into the system and make the dataset more secure; and if authentication is enhanced, then authorization can be easily gained in the Hadoop system which provides access control and access rights to resource which the user is willing to perform its function or operation. This model is implemented, and the performance has been validated using existing security variants. KEywoRdS Big Data, Cryptography Model, Hadoop, Security