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: Control theory & CMOS. The organization has 1138 authors who have published 1381 publications receiving 7798 citations.

Development of innovative lightweight slurry in oil well-cementing operations

Abstract: The innovative lightweight slurry 85 lb/ft3 (pounds per cubic foot) was prepared using three blended materials with a combination of 20% micro silica, 44% cenosphere and class-g cement, a special hydraulic binding material to forms strong bonding energy due to a combination of moderate sulphate-resistant and high sulphate-resistant. Cementing laboratory tests were carried out in the mix with this blended cement and some additives to control fluid loss increase the bonding energy and delay the cement setting time. After added this blended cement, the mechanism of the slurry was optimized the particle size distribution to maximum solids content, less water wasted in the void, the solid volume fraction increased to 50.2%. The blended composition shows fine nature and high reactivity as a pozzolanic material to improve slurry stability. Also, concluded that the high solid content increased in the slurry to enhance comprehensive strength, mechanical durability, permeability and required thickening time for low-density 85 pcf lead slurry. Pilot test results presented good compressive strength and thickening time at low temperatures.

Ethno-botanical survey of Palamalai Hills, Mettur Taluk, Eastern Ghats, India

Abstract: Ethnobotanical survey of Palamali hills, a part of Eastern Ghats was carried out for reporting the preliminary traditional knowledge from the inhabitant tribal community. Through the survey, we identified 18 plants which possess medicinal properties. This report is a preliminary checklist and will be helpful for people in identifying potential bioresource and initiating conservatory measures. The present investigation showed that, the tribes of Palamalai Hills of Mettur Taluk, Eastern Ghats, India possess rich knowledge of the medicinal plants and their utilization. There is a need of scientific awareness for prevention of most of the diseases and the cultivation of above medicinal plants for both the utilization and the conservation of natural resources.

Late Quaternary sediments on the carbonate platform off western India: Analogues of ancient platform carbonates

Abstract: The Late Quaternary carbonate sediments and sedimentary rocks from the platform off western India were reviewed for their genesis and relationship with their ancient counter parts. Sub-marine cemented and vadose diagenetic limestones were recovered at different locations on the platform and, neomorphic limestones and caliche pisolites were recovered on the continental shelf south of the platform. Dolomites on the platform were primary and formed by microbial processes under hypersaline, sulphate-reducing conditions during the lowered sea levels. Aragonite ooids were formed from the mineralization of microbial filaments that enveloped their cortex portions. Phosphorites were found in organic-rich, aragonite muds on the continental slope adjacent to the platform and formed from the microbial mineralization of organic matter and replacement of carbonate by apatite during early diagenesis. Microbial processes thus played an important role in the formation of dolomites, ooids and phosphorites reported here and those in ancient deposits. Halimeda bioherms on the platform were grown luxuriantly from the nutrients brought by upwelling currents during the Late Pleistocene–Early Holocene sea level transgression and are similar to the Holocene–Recent deposits in the Indo-Pacific region. Lime muds were bio-detrital and formed primarily from the disintegration of Halimeda bioherms and carbonate skeletal on the platform and then exported to the slope. They resemble fine-grained limestones abundantly reported in ancient platforms. Thus, the different carbonate components on the platform are genetically related to their ancient ones and serve as Late Quaternary analogues for the ancient platform carbonates.

Evolution of Synonymous Codon Usage in the Mitogenomes of Certain Species of Bilaterian Lineage with Special Reference to Chaetognatha.

Abstract: Chaetognatha is a minor phylum, comprising transparent marine invertebrates varying in size from 0.5 to 12 cm. The exact phylogenetic position of Chaetognatha in Metazoa has not been deciphered as some embryological characteristics place chaetognaths among deuterostomes and some morphological characteristics place these among protostomes. In this study, the major factors that drive synonymous codon usage bias (SCUB) in the mitogenomes of representative species of Chaetognatha and chosen species of other closely related phyla were analyzed. Spearman's rank correlation analyses of nucleotide contents suggested that mutational pressure and selection were acting in all examined mitogenomes but with varying intensities. The quantification of SCUB using effective number of codons vs. GC composition at the third codon position (GC3) plot suggested that mutational pressure due to GC compositional constraints might be one of the major influencing forces driving the SCUB in all chaetognaths except Sagitta enflata. However, neutrality plots revealed no significant correlation between GC3 and cumulative GC content at first and second codon positions (GC12) in all other species, except in Daphnia pulex. The parity rule 2 bias plot showed that significant compositional differences existed between C and G, as well as between A and T, contents in most of the protein-coding genes (PCGs) and, comparatively, A and T contents were used more proportionally than C and G contents in all chosen mitogenomes. Chi-square analysis revealed the presence of putative optimal codons in all species, except in S. enflata. The correspondence analysis identified that mutational pressure and selection act on the mitogenomes of the selected chaetognaths and other phyla with varying intensities. The cluster analysis based on relative synonymous codon usage (RSCU) values revealed that RSCU variations in the PCGs of mitogenomes of chaetognaths are more comparable with those of protostomes. Apart from mutational pressure and selection, certain unknown selective forces might be acting on the PCGs in the analyzed mitogenomes as the phenomenon of SCUB could not be explained by mutational pressure, by selection, or by both.

Current Perspectives on the Novel Structures and Antioxidant Properties of Mangrove Endophytic Fungal Exopolysaccharides

Abstract: Mangrove ecosystems are inhabited by diverse fungal endophytic communities, one of nature’s treasures of the marine biotope. Mangrove fungi comprise mostly marine fungi, and the small group of terrestrial fungi can be classified into saprophytic, parasitic, and symbiotic fungi. Fungi produce high-molecular-weight exopolysaccharides (EPSs) during their metabolic process, which plays a main role in biofilm formation and in the localization of biogeochemical processes within aggregates and sediments. In recent years, marine microbial EPSs gained momentum particularly those originating from mangrove fungi due to a specific marine environment. Mangrove fungal EPSs with unique chemical composition, diversity of structures, and properties were reportedly suitable for biotechnological applications, viz. as natural antioxidants, anticancer drugs, biosorbents, and antimicrobial agents. Knowledge of the structural characterization of EPSs could be essential to understanding the structure–function relationship of molecules. This review emphasizes the diversity of mangrove fungi and the composition, structure, and antioxidant potential of mangrove fungal EPSs.