Patterns of Allozymic Variation and Alcohol Tolerance in Indian Populations of Drosophila Bipectinata

, Ravi,Manju Sharma,Sharma, Suman 한국유전학회 1994 Genes & Genomics Vol.16 No.4

Six Indian geographical populations of D. bipectinata were analysed electrophoretically for allozymic variation at nine loci as well as for ethanol tolerance potential. Allelic frequency changes at Adh, Odh and Est-5 loci correlated significantly with increase in latitude. On the basis of F_(ST) values, Adh, Odh, Mdh and α-Gpdh loci depicted modest amounts of genetic differentiation. Thus, the occurrence of significant genotypic as well as allelic frequency heterogeneity, genic differentiation and clinal variation at polymorphic loci suggest evidence of natural selection maintaining such genic differentiation in D. bipectinata populations from the Indian sub-continent. The Indian populations of D. bipectinata revealed genetic differentiation in term of ethanol indices such as LT_(50) hrs(72 to 96 hrs), adult ethanol threshold concentration(2.5 to 4.0'%), LC_(50) thanol concentration(2.7 to 4.2%). The parallel occurrence of latitudinal variation at Adh locus as well as ethanol tolerance in Indian geographical populations of D. bipectinata could be maintained by balancing natural selection varying spatially along the north south axis of the Indian sub-continent.

Autologous Conditioned Serum as a Novel Alternative Option in the Treatment of Unilateral Lumbar Radiculopathy: A Prospective Study

Ravi Kumar H. S.,Vijay G Goni,Batra Y. K. 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.6

Study Design: The study was conducted on patients who received autologous conditioned serum (ACS) as a line of treatment at the Orthopedics outpatient department of Post Graduate Institute of Medical Education and Research (PGIMER, Chandigarh) from January 2011 to June 2012. Of the 1,224 patients, 20 males or females were included in the study based on the inclusion and exclusion criteria. The institutional board of PGIMER approved the study before it was initiated. Purpose: To study the efficacy of ACS in the treatment of unilateral lumbar radiculopathy. Overview of Literature: Interleukin (IL)-1 appears to be of special importance among the cytokines identified in orthopedic diseases. ACS contains high concentrations of IL-1 receptor antagonist, antagonist to IL-1 in that is a biochemical ‘sensitizer’ of nerve roots in radiculopathy. Methods: We included 20 patients with unilateral lumbar radiculopathy after obtaining informed consent. We prepared ACS as described by Meijer et al. Under bi-planar fluoroscopic imaging in anterior-posterior and lateral views, ACS was administered via epidural perineural technique. Patients in both groups were evaluated by quadruple visual analogue scale, straight leg raising test, revised Oswestry disability index, and 12-Item Short Form of Health Survey before and after epidural injections at 3 weeks, 3 months, and 6 months. Results: There was a statistically significant change in all parameters from pre-injection to first, second, and third follow-up (p <0.001). Conclusions: ACS can modify the disease course in addition to reducing pain, disability and improving general health.

Characterization of green ceramic-aluminum composites developed from waste recycling

Ravi Kumar Singh,Ali Algahtani,Tawfiq Al-Mughanam,Intezar Mahdi,Vineet Tirth 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.3

Green composites were prepared by recycling waste Aluminum and ceramic debris of marble and granite stones obtainedduring stone cutting at building construction sites. The composites were developed using the most economical stir castingprocess under ambient conditions with five weight percent of white marble powder and black granite powders. Themicrostructure characterization was done with my optical and SEM micrography as well as XRD. The microstructure showsfair particle distribution and improved hardness by 22-25% than the base matrix. The tensile strength and elastic modulusalso improved. The density remained stagnant due to porosity. A decline in elongation and impact strength was observed. Thestudy recommends using waste Aluminum and waste ceramic powders to develop green composites for non-critical industrialapplications such as structures, furniture, stationary machine parts, and automobile chassis.

Design and Synthesis of New Amides and Thioamides Derived from 3,4-Ethylenedioxythiophene as Potential Anticonvulsants

Ravi Kulandasamy,Airody Vasudeva Adhikari,James P. Stables 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.11

Five new series of 3,4-ethylenedioxythiophene derivatives carrying important pharamacophores, viz., amide, ester,ether and active secondary aryl moieties have been designed and synthesized through multistep reactions starting from thiodiglycolic ester and diethyl oxalate. They have been characterized by elemental and spectral data. All the target compounds have been screened for their anticonvulsant activity at three different models viz. maximal electroshock (MES), subcutaneous metrazole (scMET), and 6 Hz screen and evaluated for their neurotoxicity in rotorod model. Compound 6a emerged as lead with no neurotoxicity. All the five series of compounds are safe in the toxicity studies at the maximum dose of 300 mg/kg of body weight. Amongst the tested compounds, the ester pharmacophore with thioamide fragment has showed better activity than the other analogs.

Efficient Copper Bromide Catalyzed Chemoselective Thioacetalization of Carbonyl Compounds: Selectivity and Scope1

Ravi Varala,Sreelatha Nuvula,Srinivas R. Adapa* 대한화학회 2006 Bulletin of the Korean Chemical Society Vol.27 No.7

EDTA-functionalized KCC-1 and KIT-6 mesoporous silicas for Nd³⁺ ion recovery from aqueous solutions

Ravi, Seenu,Zhang, Siqian,Lee, Yu-Ri,Kang, Kyoung-Ku,Kim, Ji-Man,Ahn, Ji-Whan,Ahn, Wha-Seung Elsevier 2018 Journal of industrial and engineering chemistry Vol.67 No.-

<P><B>Abstract</B></P> <P>Ethylenediaminetetraacetic acid (EDTA)-functionalized KIT-6 and KCC-1 mesoporous silicas were prepared via post-synthesis grafting and examined for their ability to promote the recovery of rare earth metal ions such as Nd<SUP>3+</SUP> from an aqueous medium. The obtained adsorption isotherms were fitted to the Langmuir model, which gave a maximum adsorption of Nd<SUP>3+</SUP> ions of 109.8 and 96.5mg/g for KIT-6-EDTA and KCC-1-EDTA, respectively, at 25°C and pH 6. The adsorption kinetic profile of KIT-6 was faster than KCC-1. KIT-6 was also proved to be more stable against desorption under acidic regeneration conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ethylenediaminetetraacetic acid (EDTA) grafted KIT-6 and KCC-1 was prepared. </LI> <LI> KIT-6-EDTA showed high adsorption capacities for Nd<SUP>3+</SUP> ions in water. </LI> <LI> Adsorption equilibrium, isotherm, and kinetics were investigated. </LI> <LI> KIT-6-EDTA reused for 5 cycles without deterioration in adsorption capacities. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

On solutions of a generalized neutral logistic differential equation

Ravi P. Agarwal,J´ozef Bana´s,Reza Mollapourasl,T. Gnana Bhaskar 장전수학회 2010 Advanced Studies in Contemporary Mathematics Vol.20 No.2

We study a generalized neutral logistic differential equation with deviating argument. Using the classical Banach contraction principle on an equivalent nonlinear functional integral equation we establish the existence of a unique solution in a certain function space. A few examples along with a numerical solutions are presented.

Cycloaddition of CO₂ and epoxides over a porous covalent triazine-based polymer incorporated with Fe₃O₄

Ravi, Seenu,Puthiaraj, Pillaiyar,Park, Dong-Wha,Ahn, Wha-Seung The Royal Society of Chemistry 2018 New journal of chemistry Vol.42 No.15

<P>A highly porous quaterphenyl-containing covalent triazine polymer (QP-CTP) incorporated with iron oxide nanoparticles (Fe3O4@QP-CTP) was synthesized and applied as a catalyst for the cycloaddition of CO2 and epoxides under mild conditions. The synthesized materials were characterized using X-ray powder diffraction, N2 adsorption-desorption isotherm, X-ray photoelectron spectroscopy, transmission electron microscopy, and elemental analysis. The Fe3O4@QP-CTP composite in the presence of tetrabutylammonium bromide showed 95% conversion of epoxides with high selectivity to cyclic carbonates at 50 °C, 0.1 MPa CO2 in 12 h. The reaction kinetics was further improved upon increasing the temperature to 80 °C. The catalyst was easily recovered using a magnet, and its stability was confirmed using a recycle test, which showed that the catalyst could be re-used for a minimum of eight consecutive runs without a noticeable decline in catalytic activity. A plausible mechanistic pathway of the cycloaddition reaction over Fe3O4@QP-CTP was also proposed.</P>

Porous Covalent Organic Polymers Comprising a Phosphite Skeleton for Aqueous Nd(III) Capture

Ravi, Seenu,Puthiaraj, Pillaiyar,Yu, Kwangsun,Ahn, Wha-Seung American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.12

<P>In order to meet the ever-increasing industrial demand for rare-earth elements (REEs), it is desirable to separate and recycle them at low concentrations from various sources including industrial and urban wastes. Here, we introduced phosphorus binding sites on the hydrophobic surface of a robust and high-surface area porous polymer backbone for environmentally benign and selective recovery of REEs via adsorption. For this purpose, two porous covalent organic polymer (COP) materials incorporated with in-built phosphite functionality (P-COP-1 and P-COP-2) were synthesized and applied for the adsorptive separation of Nd(III) ions from aqueous solution. A strategy to develop a series of P-COPs via a simple Friedel-Crafts reaction was introduced, and their application to the selective adsorption of REEs was explored for the first time. The newly synthesized P-COPs were amorphous and/or weakly crystalline and showed excellent chemical stability and large specific surface area with sufficient mesoporosity for enhanced diffusion of REE ions. P-COP-1 exhibited an exceptionally high Nd(III) adsorption capacity of 321.0 mg/g, corresponding to the stoichiometric ratio of P/Nd(III) = 1:0.7 and high selectivity of >86% over other competing transition and alkaline earth metal ions, whereas P-COP-2 gave a Nd(III) adsorption capacity of 175.6 mg/g at 25 °C and pH 5. Moreover, P-COP-1 showed a distribution coefficient value of 5.45 × 10<SUP>5</SUP> mL/g, which is superior to other benchmark adsorbent materials reported so far. Finally, the P-COPs were reusable for a minimum of 10 cycles without deterioration in adsorption capacities.</P> [FIG OMISSION]</BR>

Study of Dark-Conductivity and Photoconductivity of ZnO Nano Structures Synthesized by Thermal Decomposition of Zinc Oxalate

Ravi Shankar,Rajneesh K Srivastava,S.G. Prakash 대한금속·재료학회 2013 ELECTRONIC MATERIALS LETTERS Vol.9 No.5

In the present work, zinc oxalate [ZnC2O4·2H2O] was used as precursor to prepare zinc oxide nano structures by thermal decomposition. Its photoconductivity and dark-conductivity properties have been studied in air as well as in vacuum. Voltage dependence of photocurrent and dark-current has been observed at room temperature in air under UV-vis illumination and is found as superlinear in nature. Rise and decay curve in air exhibits anomalous behavior wherein the photocurrent decreases even during steady illumination. In vacuum,the rise of photocurrent becomes slow and prolonged.