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American Journal of Analytical Chemistry 2024年第3期15卷 119-133页

作者： Anwar Sulaiman k. ramakrishna reddy Vundavilli Jagadeesh k.mar Hemant k.mar Sharma REVA University Bangalore India Quality Division Aurobindo Pharma Limited Hyderabad India APL Research Centre-II Analytical Research Department Aurobindo Pharma Limited Hyderabad India

Potential mutagenic impurities in Active Pharmaceutical Ingredient, Meropenem Trihydrate were assessed and a novel analytical method for their quantification was developed and validated. This Liquid Chromatographic method using High Resolution Mass Spectrometer (LC-HRMS) technique is proved to be suitable for simultaneous quantification of all ten identified impurities with required specificity, sensitivity, resolution, precision, accuracy, and other method characteristics as per ICH Guidelines. The acceptable limit of less than 2.9 μg/g was considered for evaluations, based on drug substance dosage and duration of treatment. The method stands most sensitive with a Limit of Detection of 0.35 μg/g, considering the challenge full acceptance criteria as per current regulatory standards.

关键词： Mutagenic Impurities LC-HRMS Meropenem Trihydrate Method Validation

Facile one-step hydrothermal route to MSe/Mo_(3)Se_(4)(M:Zn,Mn,and Ni)-based electrode materials for ultralong-life hybrid supercapacitors

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Journal of Materials Science & Technology 2023年第25期156卷 230-240页

作者： B.N.Vamsi k.ishna Obula reddy Ank.napalli Ayyaluri ramakrishna reddy Jae Su Yu Department of Electronics and Information Convergence Engineering Institute for Wearable Convergence ElectronicsKyung Hee UniversityYongin-siGyeonggi-do 17104Republic of Korea

Transition metal selenides have attracted great interest in electrochemical energy storage applications because of their good electrochemical activity and conductivity ***,we reported the metal molybdenum selenide(M Se/Mo_(3)Se_(4)(M:Zn,Mn,and Ni))electrode materials on their morphological and electrochemical properties by varying the metal ions via a facile hydrothermal *** effects of the structural,morphological,and surface area properties of the prepared powder materials on their electrochemical performance were *** to the hierarchical porous and unique interconnected structure,the nick.l molybdenum selenide nanosheet spheres(NMS NSSs)-based electrode material delivered an excellent specific capacity value of 252 mAh g^(-1) at a current density of 1 Ag^(-1).Moreover,the optimized NMS NSSs electrode exhibited outstanding cycling stability with a capacity retention of 80%and a corresponding coulombic efficiency of 99%after 80,000 ***,a pouch-type hybrid supercapacitor(HSC)device was assembled using NMS NSSs material as a positive electrode and activated carbon as a negative electrode in 1 M aqueous k.H ***,the assembled HSC device exhibited superior energy and power density values as well as magnificent cycling *** real-time practical applications,light-emitting diodes and a digital display were powered using two series-connected HSC ***,the obtained tremendous results strongly suggest that the NiSe/Mo_(3)Se_(4) NSSs-based materials could be a promising electrode for ultralong-life energy storage applications.

关键词： Nick.l selenides Molybdenum selenides Nanosheet spheres Ultralong-life cycling stability

Spectral change and far-red emission of Mn^(2+)ions co-doped NaSrB_(5)O_(9):Dy^(3+)luminescence material for plant growth LEDs

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Journal of Rare Earths 2022年第2期40卷 218-225,I0002页

作者： k.Munirathnam k.duru Mallik.rjuna R.Vijaya P.C.Nagajyothi k.ramakrishna reddy M.Srinivas Department of Physics School of Applied SciencesREVA UniversityBengaluru560064India Department for Management of Science and Technology Development Ton Due Thang UniversityHo Chi Minh CityVietnam Faculty of Applied Sciences Ton Due Thang UniversityHo Chi Minh CityVietnam Department of Physics Visvodaya Government Degree CollegeVenkatagiri524132India School of Mechanical Engineering Yeungnam UniversityGyeongsan33541South Korea Department of Chemistry School of Applied SciencesREVA UniversityBengaluru560064India

Due to the characteristic emission of phosphors,phosphor-converted LEDs have been employed to provide the requisite light sources for indoor plant growth in the optical agricultural ***,we prepared a series of Mn^(2+)co-doped NaSrB5 O9:Dy^(3+)phosphors via a solid-state reaction *** phosphors have significant three-band emissions at 467 nm(blue region),606 nm(orange region),and765 nm(far-red region),ascribed to the^(4)F_(9/2)-^(6)H_(15/2)and 4 F9/2-6 H13/2 transitions of the Dy^(3+)ions and the^(4)T_(1g)(G)-^(6)A_(1g)(S)spin-forbidden transition of the Mn^(2+)ions,respectively,when excited by light of 376 nm(near-UV region).The co-dopant in the host material facilitates tunable photoluminescence(PL)due to energy transfer from the Dy^(3+)ions to the Mn^(2+)*** three emission peak. from the prepared phosphors well match with the absorption spectra of the photosynthesis pigments of plants,chlorophyll and phytochrome,which can absorb blue(400-500 nm),orange-red(550-700 nm),and infrared(IR)radiation,indicating that these phosphors have potential applications in the fabrication of plant-growth *** to the PL studies,the structure of the phosphors was determined by X-ray diffraction,refined by Rietveld method and chemically quantified by X-ray photoelectron spectroscopy.

关键词： Phosphors Refinement X-ray photoelectron spectroscopy Energy transfer Plant growth LEDs Rare earths

Synthesis and Characterization of C-TiO_2/FeTiO_3 and CQD/C-TiO_2/FeTiO_3 Photocatalysts with Enhanced Photocatalytic Activities Under Sunlight Irradiation

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Acta Metallurgica Sinica(English Letters) 2016年第1期29卷 17-27页

作者： ramakrishna Dadigala Bhagavanth reddy Gangapuram Rajk.mar Bandi Ayodhya Dasari Veerabhadram Guttena Department of Chemistry Osmania University

Sunlight-driven C-TiO2/FeTiO3 composites were synthesized with different weight fractions of FeTiO3. The as-prepared samples were characterized by UV-Visible diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, energy-dis- persive X-ray spectroscopy, and photoluminescence. Under sunlight irradiation, the C-TiO2/FeTiO3 photocatalysts degraded methyl orange （MO） efficiently and displayed much higher photocatalytic activity than that of pure FeTiO3 or carbon-doped titanium dioxide （C-TiO2）, and the C-TiOE/FeTiO3 photocatalyst with 10 wt% of FeTiO3 exhibited the highest photocatalytic activity. The enhancement of photocatalytic activity was mainly ascribed to the formation of a heterojunction between C-TiO2 and FeTiO3, which facilitated the transfer and separation of photogenerated electron-hole pairs. The quenching effects of different scavengers demonstrated that the reactive superoxide radicals （02-） and hydroxyl radicals （OH） played a major role in the MO degradation. The possible photocatalytic mechanism is discussed on the basis of the band structures of C-TiO2 and FeTiO3. To further enhance the photocatalytic efficiency, double-heterojunctioned CQD/C-TiO2/FeTiO3 composite was prepared by loading carbon quantum dots onto the C-TiO2/FeTiO3 surface.

关键词： C-TiO2 FeTiO3 CQD Composites Sunlight photocatalytic activity

Novel functional association of rat testicular membrane-associated cytosolic glutathione S transferases and cyclooxygenase in vitro

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Asian Journal of Andrology 2005年第2期7卷 171-178,页

作者： S.Neeraja B.ramakrishna A.S.Sreenath G.V.reddy P.R.k.reddy P.Reddanna Department of Animal Sciences School of Life SciencesUniversity of HyderabadHyderabad 500046India

Aim:To analyze the role of cytosolic glutathione S-transferases (cGSTs) and membrane-associated cytosolic GSTs (macGSTs) in prostaglandin biosynthesis and to evaluate the possible interaction between glutathione S-transferases (GSTs) and cyclooxygenase (COX) in ***:SDS-PAGE analysis was undertak.n for characterization of GSTs,thin layer chromatography (TLC) to monitor the effect of GSTs on prostaglandin biosynthesis from arachi- donic acid (AA) and spectrophotometric assays were done for measuring activity levels of COX and ***: SDS-PAGE analysis indicates that macGSTs have molecular weights in the range of 25-28 *** a coupled assay involving GSTs,arachidonic acid and cyclooxygenase-1,rat testicular macGSTs produced prostaglandin E2 and F2~, while the cGSTs caused the generation of prostaglandin D2,E2 and F_(2α).In vitro interaction studies on GSTs and COX at the protein level have shown dose-dependent inhibition of COX activity by macGSTs and vice *** effect, however,is not seen with *** inhibitory effect of COX on macGST activity was relieved with increasing concentrations of reduced glutathione (GSH) but not with 1-chloro 2,4-dinitrobenzene (CDNB).The inhibition of COX by macGSTs,on the other hand,was potentiated by ***:We isolated and purified macGSTs and cGSTs from rat testis and analyzed their involvement in prostaglandin *** studies reveal a revers- ible functional interaction between macGSTs and COX in vitro,with possible interactions between them at the GSH binding site of macGSTs.

关键词： glutathione S-transferase cyclooxygenase arachidonic acid glutathione prostaglandins

Metal Organic Framework.Derived Zirconia-Carbon Nanoporous Mat for Integrated Strain Sensor Powered by Solid‑State Supercapacitor

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Advanced Fiber Materials 2023年第4期5卷 1404-1416页

作者： Brindha Ramasubramanian Vundrala Sumedha reddy Ye Zhen Seeram ramakrishna Vijila Chellappan Department of Mechanical Engineering Center for Nanofibers and NanotechnologyNational University of SingaporeSingapore 117574Singapore Institute of Materials Research and Engineering(IMRE) Agency for ScienceTechnology and Research(A*STAR)#08‑032 Fusionopolis WayInnovisSingapore 138634Singapore

Flexible electronics are essential for the rapid development of human-machine interface technology,encompassing sensors and energy storage ***-state supercapacitors with 1D nanofiber electrodes are critical for enhancing ion *** this study,a flexible supercapacitor integrated with a strain sensor was designed using a polyvinyl alcohol/polymethyl methacrylate(PVA/PMMA)-based electrolyte and a metal-organic framework.MOF)-derived Zr-nanoporous carbon mat(Zr-NPC).The sensor showed remark.ble sensitivity over a broad strain range,enabling reliable and precise detection of mechanical *** supercapacitor with Zr-NPC@PVDF electrode also demonstrated a specific capacitance of 286 mF cm^(-2) at 0.5 mA cm^(-2),maintaining high flexibility and mechanical *** fabricated supercapacitor maintained around 81%charge retention after 10,000 ***,the self-powered integrated model was directly connected to the human body to detect physical motion,accentuating its potential for widespread applications in wearable technology.

关键词： Supercapacitor Piezoresistive sensor Porosity Nanocarbon

Investigations on Heat Transfer Enhancement in Pool Boiling with Water-CuO Nano-Fluids

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Journal of Thermal Science 2012年第2期21卷 179-183页

作者： ramakrishna N. Hegde Dr. Shrik.ntha S. Rao R. P. reddy Research Scholar National Institute of Technology Surathkal/ Department of Mechanical Engineering M S R I T Bangalore 560054 Assistant Professor Department of Mechanical Engineering National Institute of Technology Surathkal Reva Institute of Technology Yelahanka Bangalore 560064

The main focus of the present work.is to investigate Critical Heat Flux (CHF) enhancement using CuO nanofluid relative to CHF of pure water. To estimate the effect of nanoparticles on the CHF, pool boiling CHF values were measured for various volume concentrations of CuO nanofluid and compared with pure water. CHF enhancement of 130% was recorded at 0.2 % by volume of CuO nano-fluids. Surface roughness of the heater surface exposed to three measured heating cycles indicated surface modifications at different volume concentrations of nanofluid. SEM image of the heater surface revealed porous layer build up, which is thought to be the reason for CHF enhancement.

关键词： Nanofluid pool boiling CHF enhancement nano-particle.

Efficacy of low dose peginterferon alpha-2b with ribavirin on chronic hepatitis C

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World Journal of Gastroenterology 2006年第34期12卷 5554-5556页

作者： Rajesh Gupta CH ramakrishna Sandeep Lak.tak.a Manu Tandan Rupa Banerjee D Nageshwar reddy Department of Medical Gastroenterology and Hepatology Asian Institute of Gas-troenterology Somajiguda 63661 Hyderabad India

AIM: To assess the effi cacy of peginterferon alpha 2b at doses of 50 μg week.y and 80 μg week.y (based on body weight) plus ribavirin in HCV genotype 2 and genotype 3 chronic hepatitis C patients. METHODS: During the study period of Jan 2002 to Dec 2003, all patients diagnosed as chronic hepatitis C or HCV related compensated cirrhosis were treated with peginterferon alpha 2b 50 μg S/C week.y (body weight k.) or 80 μg S/C week.y (body weight > 60 k.) plus ribavirin 800 mg/d for 24 wk. RESULTS: Overall 28 patients, 14 patients in each group (based on body weight) were treated during the period. Out of 28 patients, 75% were genotype 3, 18% were genotype 2 and 7% were genotype 1. The mean dose of peginterferon alpha 2b was 0.91 μg/k. in group 1 and 1.23 μg/k. in group 2 respectively. The end of treatment and sustained virologic response rates were 82% and 78% respectively. Serious adverse effects were seen in 3.5% patients. CONCLUSION: Low dose peginterferon alpha 2b in combination with ribavirin for 24 wk.is effective in HCV genotype 2 and 3 chronic hepatitis C patients.

关键词： Chronic hepatitis C Peginterferon alpha 2b Ribavirin

Mantle heterogeneity,plume-lithosphere interaction at rift controlled ocean-continent transition zone:Evidence from trace-PGE geochemistry of Vempalle flows,Cuddapah Basin,India

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Geoscience Frontiers 2018年第6期9卷 1809-1827页

作者： Th.Dhanak.mar Singh C.Manik.amba k.S.V.Subramanyam Sohini Ganguly Arubam C.k.elen N.ramakrishna reddy CSIR-National Geophysical Research Institute(Council of Scientific and Industrial Research) Uppal RoadHyderabad 500007India Goa University Taleigao PlateauGoa 403206India Department of Geology Loyola CollegePulivendlaCuddapahAndhra PradeshIndia

This study reports major, trace, rare earth and platinum group element compositions of lava flows from the Vempalle Formation of Cuddapah Basin through an integrated petrological and geochemical approach to address mantle conditions, magma generation processes and tectonic regimes involved in their formation. Six flows have been identified on the basis of morphological features and systematic three-tier arrangement of vesicular-entablature-colonnade zones. Petrographically, the studied flows are porphyritic basalts with plagioclase and clinopyroxene representing dominant phenocrystal *** and trace element characteristics reflect moderate magmatic differentiation and fractional crystallization of tholeiitic magmas. Chondrite-normalized REE patterns corroborate pronounced LREE/HREE fractionation with LREE enrichment over MREE and HREE. Primitive mantle normalized trace element abundances are mark.d by LILE-LREE enrichment with relative HFSE depletion collectively conforming to intraplate magmatism with contributions from sub-continental lithospheric mantle(SCLM) and extensive melt-crust interaction. PGE compositions of Vempalle lavas attest to early sulphur-saturated nature of magmas with pronounced sulphide fractionation, while PPGE enrichment over IPGE and higher Pd/Ir ratios accord to the role of a metasomatized lithospheric mantle in the genesis of the lava flows. HFSEREE-PGE systematics invok. heterogeneous mantle sources comprising depleted asthenospheric MORB type components combined with plume type melts. HFSE-REE variations account for polybaric melting at variable depths ranging from garnet to spinel lherzolite compositional domains of mantle. Intraplate tectonic setting for the Vempalle flows with P-MORB affinity is further substantiated by(i) their origin from a rising mantle plume trapping depleted asthenospheric MORB mantle during ascent,(ii) interaction between plume-derived melts and SCLM,(iii) their rift-controlled intrabasinal emplacement th

关键词： Cuddapah basin Vempalle lava flows Sulphide fractionation Partial melting Plume-lithosphere Intraplate rifting

Determination of genotoxic alk.l methane sulfonates and alk.l paratoluene sulfonates in lamivudine using hyphenated techniques

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Journal of Pharmaceutical Analysis 2012年第4期2卷 314-318页

作者： N.V.V.S.S.Raman A.V.S.S.Prasad k.Ratnak.r reddy k.ramakrishna Hetero Drugs Ltd.(R&D) GITAM Institute of Science GITAM University

Two highly sensitive methods for the determination of genotoxic alk.l methane sulfonates (AMSs) and alk.l paratoluene sulfonates (APTSs) in lamivudine using hyphenated techniques have been presented. AMSs were determined by GC-MS method using GSBPINOWAX (30 m 0.25 mm 0.25 mm) column. Temperature program was set by maintaining at 100 1C initially for 3 min, then rised to 220 1C at the rate of 15 1C/min and maintained at 220 1C for 16 min. N,N-dimethyl formamide was used as diluent. APTSs were determined by LC-MS using Zorbax, Rx C8, 250 mm 4.6 mm, 5 mm column as stationary phase. 0.01 M ammonium acetate is used as buffer. The mixture of buffer and methanol in 75:25 (v/v) ratio was used as mobile phase A and mixture of buffer and methanol in 5:95 (v/v) ratio was used as mobile phase B. The gradient program (T/%B) was set as 0/28, 16/50, 17/100, 23/100, 27/28 and 40/28. Both the methods were validated as per International Conference on Harmonization guidelines. Limit of quantitation was found 1.5 mg/mL for AMSs and was in the range of 1.0-1.5 mg/mL for APTSs.

关键词： Genotoxins Alk.l methane sulfonates Alk.l paratoluene sulfonates Lamivudine Hyphenated techniques