Publications by authors named "Sreenivasulu G"

An efficient dual gold-catalyzed regioselective synthesis of benzofulvenes has been developed from substituted allyloxy 1,5-diynes 5- cyclization. In this intramolecular organic transformation a new C-C bond formation occurs and moderate to very good yields are obtained in one pot.

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An efficient synthetic method was developed to access isoquinoline-derived diene esters from enynones and isoquinoline--oxides in an atom-economic manner. The isoquinoline-substituted diene esters were obtained in moderate to excellent yields via [3 + 2]-cycloaddition and isoxazole ring opening followed by a [1,5]-sigmatropic rearrangement reaction, which resulted in one C-C and two C-O bond formations. Further, quinolin-2(1)-ylidene-substituted 1,5-diones were achieved by reaction of enynones with quinoline--oxides in very good to high yields.

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COVID-19 has sparked a global pandemic, with a variety of inflamed instances and deaths increasing on an everyday basis. Researchers are actively increasing and improving distinct mathematical and ML algorithms to forecast the infection. The prediction and detection of the Omicron variant of COVID-19 brought new issues for the health fraternity due to its ubiquity in human beings.

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The Dead Sea (DS) sediment samples from two different sites on the west coast were analyzed. The objective is to document sediment characterization in order to study the interrelation existing among ingredients. The analyses show that Fe, Mg and Zn are the most significant trace elements found in the Sediment.

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An efficient intramolecular cyclization reaction was developed to achieve indenone derivatives. The substituted 1,5-diyenes were converted to the corresponding indenones via a gold-catalyzed organic transformation, and moderate to excellent yields of the title molecules were obtained via formation of two C=O and one C-C bonds under mild reaction conditions in one pot.

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AC1497 is an effective dual inhibitor of malate dehydrogenase 1 and 2 targeting cancer metabolism. However, its poor aqueous solubility results in low bioavailability, limiting its clinical development. This study was conducted to develop an effective self-nanoemulsifying drug delivery system (SNEDDS) of AC1497 to improve its oral absorption.

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An efficient gold-catalyzed formation of indenylidene-derived 1H-isochromene-4-carbaldehydes from substituted 1,5,10-triyne-O-silanes was developed under mild reaction conditions. In this reaction, gold-catalyzed selective oxidation, 1,2-migration, nucleophilic addition and then 5-endo-dig cyclization took place regioselectively. The indenylidene-derived isochromene-4-carbaldehydes were synthesized in moderate to very good yields via the formation of new C-C and C-O bonds in one pot.

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This report is on studies directed at the nature of magneto-electric (ME) coupling by ferromagnetic resonance (FMR) under an electric field in a coaxial nanofiber of nickel ferrite (NFO) and lead zirconate titanate (PZT). Fibers with ferrite cores and PZT shells were prepared by electrospinning. The core-shell structure of annealed fibers was confirmed by electron- and scanning probe microscopy.

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The benthic foraminiferal diversity index was computed from Beypore estuary sediments. The abundance and diversity of Quinqueloculina lata, Textularia agglutinans, Haplophagmoides canariensis, and Quinqueloculina stelligera were dominated by stress-tolerant taxa such as Ammonia tepida, A.parkinsoniana, Nonion grateloupi, and N.

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Ferrite-ferroelectric core-shell nanoparticles were prepared by deoxyribonucleic acid (DNA) assisted self-assembly and the strained mediated magneto-electric (ME) interactions between the ferroic phases were studied. The nanoparticle type and size were varied and the DNA linker sequence was also varied. Two kinds of particles, one with 600 nm barium titanate (BTO) core and 200 nm nickel ferrite (NFO) shell and another with 200 nm BTO core and 50 nm nickel cobalt ferrite (NCFO) shell were prepared.

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X-ray diffraction (XRD), Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS), and Fourier Transform Infrared Spectroscopy (FT-IR), were applied to analyze the organic matrix of two . The are mineral structure and calcium carbonate crystallized as aragonite. The FT-IR spectra showed Alkyl Halide, Alkanes, Alcohols, Amides, Aromatic, and Hydroxyl groups in the organic matrix of the whole (organic and mineral) Molluscan shells.

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Ferromagnetic-ferroelectric nanocomposites are of interest for realizing strong strain-mediated coupling between electric and magnetic subsystems due to a high surface area-to-volume ratio. This report is on the synthesis of nickel ferrite (NFO)-barium titanate (BTO) core-shell nanofibers, magnetic field assisted assembly into superstructures, and studies on magneto-electric (ME) interactions. Electrospinning techniques were used to prepare coaxial fibers of 0.

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Pulicat Lake is one of the major wetlands in India. It is the second largest brackish water lagoon in India next to Chilika Lake in Orissa state. Pulicat Lake sits beside the Bay of Bengal so, the study on the mouth is vital.

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Fourier Transform Infrared Spectroscopy (FTIR) was used to study the variations in organic matters of benthic foraminifera from four samples collected from beach environments from brackish environments along Tupilipalem coast (South east coast of India). Common absorption bands were observed as peaks in the range of 3600-3400 cm, 3000-2850 cm, 1750-1740 cm, 1640-1600 cm, 1450-1350 cm, 885-870 cm and 725-675 cm in all the shells of . The FTIR spectrum of station-1 represents the presence of alkanes (CH) and alkyl halide (C-F stretching) with absorptions at the range 1385-1255 and 1350-1150 cm were observed and ether (C-O stretching) absorption band was observed at stations 1 and 3 with wavenumber of 1115 cm and 1117 cm respectively.

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A total of 112 bottom water and sediment samples collected at fixed stations in pre-monsoon and post-monsoon from four estuaries (Pennar, Uppateru, Swarnamukhi, and Kalangi) showed foraminiferal test abnormalities in heavy metal concentrations (Co, Cr, Cu, Fe, Mn, Ni, and Pb). Low diversity of fauna was due to the predominance of a limited number of opportunistic species capable of achieving high densities in adverse environmental conditions and the reduction in the number of species intolerant of such conditions. In this study, classification of 54 common species according to their distribution is presented.

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Multiferroic composites with ferromagnetic and ferroelectric phases have been studied in recent years for use as sensors of AC and DC magnetic fields. Their operation is based on magneto-electric (ME) coupling between the electric and magnetic subsystems and is mediated by mechanical strain. Such sensors for AC magnetic fields require a bias magnetic field to achieve pT-sensitivity.

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In fish, oocyte meiotic maturation is regulated by 17α, 20β-dihydroxy-progesterone through cAMP. To study the role of cAMP response element binding protein (CREB) in meiotic maturation, we cloned and characterized the expression pattern of CREBs from two fish models, the Nile tilapia and catfish. In the Nile tilapia three different CREBs were identified where in CREB1 was found in many tissues including gonads with abundant expression in testis.

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Multifunctional materials have attracted many interests from both fundamental and practical aspects, such as field-effect transistor, electric protection, transducers and biosensor. Here we demonstrated the first superior hydrophobic piezoelectric surface based on the polymer blend of polyvinylidene fluoride (PVDF)-polyacrilonitrile (PAN) assisted with functionalized multiwalled nanotubes (MWNTs), by a modified electrospinning method. Typically the β-phase polyvinylidene fluoride (PVDF) was considered as the excellent piezoelectric and pyroelectric materials.

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Thyroid hormones play crucial role in several biological processes including reproduction. Disruption of normal thyroid status by environmental contaminants can cause severe impairment in reproductive functions. In our previous study, we reported down-regulation of a protein in seminal vesicular fluid of air-breathing catfish, Clarias gariepinus during experimentally induced hyperthyroidism.

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Teleostean 20β-hydroxysteroid dehydrogenase (20β-HSD) is involved in final oocyte maturation and steroid hormone metabolism. It has structural and functional similarities to mammalian carbonyl reductases that are involved in the metabolism of endogenous carbonyl and xenobiotic compounds. To understand the transcriptional regulation of 20β-HSD, here we report the cloning of 20β-HSD promoter from two fish species, rainbow trout and air-breathing catfish.

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The maturation inducing hormone, 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-DP) is required for the meiotic maturation and is produced from the precursor 17α-hydroxyprogesterone by the enzyme 20β-hydroxysteroid dehydrogenase (20β-HSD) in several teleosts. Central role of 20β-HSD in ovarian cycle and final oocyte maturation is well studied when compared to spermatogenesis. In the present study, we investigated the localization and expression of 20β-HSD in testicular cycle and gonadotropin induced sperm maturation.

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A new synthesis route with high energy ball milling and microwave sintering is used to obtain nanocrystalline BiFeO3 with improved dielectric and magnetic properties. Electrical and magnetic properties are compared with a conventionally sintered microcrystalline BiFeO3. It is found that the dielectric constant is increased more than one order of magnitude, electrical resistivity by six orders of magnitude and remnant polarization value is increased by 4-5 times for nanocrystalline BiFeO3 in comparison to conventionally sintered microcrystalline BiFeO3.

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Cytochrome P450 17alpha-hydroxylase/c17-20 lyase (P450c17) is regarded as one of the key enzymes involved in the steroidogenic shift that occurs prior to oocyte maturation in teleosts. Role of P450c17 in the shift in steroidogenesis during oocyte maturation is a contentious issue even after identification of a novel type of P450c17 that lacks lyase activity. To understand the role of P450c17 in steroidogenic shift explicitly, a full length cDNA encoding p450c17 from ovary of air-breathing catfish, Clarias gariepinus was cloned.

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Complementary DNAs encoding steroidogenic acute regulatory protein (StAR) have been isolated from different fish species, yet the relevance of StAR during gonadal cycle and more importantly in final oocyte maturation has not been assessed so far. A cDNA encoding StAR was isolated from the ovarian follicles of air-breathing catfish, Clarias gariepinus. Catfish StAR exhibited 55 to 72% identity at nucleotide level with other vertebrate orthologs.

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20beta-hydroxysteroid dehydrogenase (20beta-HSD) synthesizes 17alpha,20beta-dihdroxy-4-pregnen-3-one, the steroid required for resumption of prophase-I arrested oocytes in teleosts. Though 20beta-HSD cDNAs have been cloned from few fish species, its role in final oocyte maturation (FOM) is still questionable. To study the role of 20beta-HSD in FOM more explicitly, we cloned and characterized 20beta-HSD from ovary of air-breathing catfish, Clarias gariepinus.

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