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Annealing effects on the structural and optical properties of ZnO nanoparticles with PVA and CA as chelating agents

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Journal of Advanced Ceramics 2015年第2期4卷 123-129页

作者： A.N.MALLIKA A.ramachandra reddy K.Venugopal reddy Department of Physics Materials Science LaboratoryNational Institute of TechnologyWarangal-506004TelanganaIndia

The effects of annealing temperatures and chelating agents on the structural and optical properties of ZnO nanoparticles were *** average particle size of ZnO nanoparticles increased with increase of annealing *** decrease of the full width at half maximum(FWHM)with increasing annealing temperatures inferred increase of particle/grain *** grain sizes were also observed to be increased with increase of annealing *** the absorption spectra of the samples,the absorption was red-shifted and the energy band gap was blue-shifted with increase of annealing temperatures.A sharp UV emission peak was observed and the intensity of this peak increased with annealing temperatures corresponding to the high crystallinity in the *** high annealing temperature of 700℃,ZnO exhibited a less intense deep level *** negligible deep level emission was attributed to the oxygen vacancies created at higher annealing temperatures.

关键词： ZnO nanostructures citric acid(CA) polyvinyl alcohol(PVA) chelating agents scanning electron microscopy(SEM) optical properties

Synthesis and optical characterization of porous ZnO

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Journal of Advanced Ceramics 2013年第3期2卷 260-265页

作者： K.SOWRI BABU A.ramachandra reddy Ch.SUJATHA K.VENUGOPAL reddy A.N.MALLIKA Department of Physics National Institute of Technology WarangalWarangal-506004Andhra PradeshIndia

In this paper,a simple and cheap method to prepare porous ZnO by using zinc nitrate,ethanol and triethanolamine(TEA)is *** as-prepared sample consisted of nano and micro *** sample was calcined at 300℃,400℃and 500℃with different heating *** 500℃,the nano pores disappeared but the sample maintained its micro *** emission scanning electron microscopy(FE-SEM)pictures confirmed that the size and growth of ZnO nanoparticles depended on the heating *** infrared(IR)absorption peak of Zn-O stretching vibration positioned at 457 cm^(-1)was split into two peaks centered at 518 cm^(-1)and 682 cm^(-1)with the change of *** results confirmed that Fourier transform infrared(FT-IR)spectrum was sensitive to variations in particle size,shape and *** photoluminescence(PL)spectrum of porous ZnO contained five emission peaks at 397 nm,437 nm,466 nm,492 nm and 527 *** intensity enhanced monotonously with increase of temperature and the change was rapid between temperatures of 300℃and 500℃.This was due to the elimination of organic species and improvement in the crystallanity of the sample at 500℃.

关键词： semiconductors porous ZnO optical properties

Solid-liquid extraction of Gd(Ⅲ) and separation possibilities of rare earths from phosphoric acid solutions using Tulsion CH-93 and Tulsion CH-90 resins

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Journal of Rare Earths 2012年第12期30卷 1270-1275页

作者： S.Radhika V.Nagaraju B.Nagaphani Kumar M.Lakshmi Kantam B.ramachandra reddy Inorganic Chemistry Division Indian Institute of Chemical Technology(IICT) Rubamin Limited Halol-389 350India

Solid-liquid extraction of gadolinium was investigated from phosphoric acid medium using commercial amino phosphonic acid resin, Tulsion CH-93. The experimental conditions studied included equilibration time, acid concentration, mass of the resin, metal concentration, loading and elution. The percent extraction of Gd（Ⅲ） was studied as a function of phosphoric acid （0.05-3 mol/L） using Tulsion CH-93 resin. The corresponding lgD vs. equilibrium pH plot gave straight line with a slope of 1.8. The percent extraction decreased with acid co centration increasing, conforming ion exchange mechanism. Under observed experimental conditions the loading capacity of Tulsion CH-93 for gadolinium was 10.6 mg/g. Among several eluants screened, the quantitative elution of Gd（III） from loaded Tulsion CH-93 was obtained with ammonium oxalate （0.15 mol/L）. The extraction behavior of commonly associated metals with gadolinium was studied as a function of phosphoric acid concentration. Tulsion CH-93 resin showed selective extraction towards heavy rare earths （Lu and Yb） which could be separated from other rare earths at 3 mol/L H3PO4, similar to wet phosphoric acid （3-5 mol/L）. On the other hand Gd（Ⅲ） and other rare earths were studied with chelating resin Tulsion CH-90. Light rare earths were highly extracted and these could be separated from heavy rare earths and Gd.

关键词： gadolinium phosphoric acid Tulsion CH-93 Tulsion CH-90 separation factors rare earths

Chemical composition, antibacterial and antifungal activities of Saudi Arabian Mentha longifolia L. essential oil

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Journal of Coastal Life Medicine 2017年第10期5卷 441-446页

作者： Nagarjuna reddy Desam Abdul Jabbar Al-Rajab Mukul Sharma Mary Moses Mylabathula ramachandra reddy Gowkanapalli Albratty Mohammed Center for Environmental Research and Studies Jazan UniversityJazanSaudi Arabia Department of Biotechnology College of ScienceKrishna UniversityMachilipatnamA.P.India Department of Polymer science and Technology College of ScienceAnatapuramA.P.India Department of Pharmaceutical Chemistry Faculty of PharmacyJazan UniversityJazanSaudi Arabia

Objective: To investigate the chemical composition, in vitro antibacterial and antifungal activity of Mentha longifolia L. essential oils using aqueous extract. Methods: Mentha longifolia L. essential oils were extracted using hydrodistillation with Clevenger apparatus for 3 h and the yield of the essential oil was calculated. Essential oils were qualitatively and quantitatively analyzed with gas chromatography and gas chromatography-mass spectrometer. For these essential oils, antibacterial and antifungal activity against human pathogens were evaluated. Results: Nineteen chemical constituents representing 99.72% of the essential oil were found, comprising menthone (39.55%), isopulegone (30.49%), eucalyptol (10.38%), and α-terpineol (3.15%);these were major components, and others were minor components. The essential oil showed strong antibacterial activity against Staphylococcus aureus [(35.24 ± 0.13) mm], Enterococcus faecalis [(32.12 ± 0.12) mm] and Bacillus cereus [(30.06 ± 0.04) mm], as well as antifungal activity against Aspergillus flavus [(38.02 ± 0.06) mm], Alternaria alternaria [(35.26 ± 0.12) mm], and Penicillum spp ((34.14 ± 0.02) mm)Conclusions: It seems that the essential oils derived from the Mentha longifolia L. species could be used as a natural source of antimicrobial agents.

关键词： Chemical composition Essential oil Antibacterial Antifungal Mentha longifolia L. Menthone Isopulegone Eucalyptol

New Method of Palladium Metal Trapping through Resins in Antiviral Drug: Valacyclovir HCl

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International Journal of Organic Chemistry 2013年第4期3卷 251-255页

作者： Keshava Navin Kumar reddy Murugulla Adharvana Chari Mayur D. Khunt V. V. N. K. V. Prasada Raju Bojja ramachandra reddy Vurimidi Himabindu Ghanta Mahesh reddy Department of Chemistry Institute of Science and Technology J. N. T. University Kukatpally Hyderabad India Dr. MACS Bio-Pharma Pvt. Ltd. Western Hills Kukatpally Hyderabad India Research and Development Integrated Product Development Innovation Plaza Dr. Reddy’s Laboratories Ltd. Bachupally Quthubullapur India

This process describes a novel technique for effective trapping of “Pd” metal through resins during the process development of L-valine, 2-[(2-amino-1,6-dihydro-6-oxo-9H-purin-9-yl) methoxy] ethyl ester, and mono hydrochloride known as a Valacyclovir hydrochloride (1). This technique is suitable for large-scale production of 1 and it is described here Pd metal trapping by using different resins.

关键词： Valacyclovir Hydrochloride Antiviral Drug N-Phthalimide-L-Valine Ester Monomethylamine Commercially Scalable Process Less Cycle Time

Bio-Synthesis of Silver Nanoparticles from Leaf Extract of <em>Pongamia pinnata</em>as an Effective Larvicide on Dengue Vector <em>Aedes albopictus</em>(Skuse) (Diptera: Culicidae)

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Advances in Entomology 2014年第2期2卷 93-101页

作者： Bannoth reddya Naik G. Swarna Gowreeswari Yuvo Singh R. Satyavathi S. S. Daravath P. ramachandra reddy Department of Botany Osmania University Hyderabad India Department of Zoology Division of Medical Entomology University College of Science Osmania University Hyderabad India School of Physics Hyderabad Central University Hyderabad India

The frequent cases of dengue incidences are leading cause of illness and death in urban areas and Aedes albopictus (Skuse) is a primary vector for Dengue transmission in India. Synthesis of leaf mediated silver nanoparticles especially with Pongamia pinnata is a potential substitute for the existing organophosphorus insecticides like Tenophos, malathion and fenthion etc., for mosquito control programme. The nanoparticles were characterized by UV-visible absorption spectrum, X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) and Transmission Electron Microscopy (TEM). Analysis of TEM showed that the synthesized silver nanoparticles are in spherical shape with average size of 20 nm. Further the XRD analysis confirms the nano-crystalline phase of silver with face centred cubic (FCC) crystal structure. GC-MS analysis elucidated the presence of two active ingredients, such as 9-Octadecenoic acid (Z) and n-hexadecanoic acid, which are the prominent substances considered as larvicide. Larvae were exposed to varying concentrations of plant extracts and synthesized silver nanoparticles for 24 hours. From the results, it is found that plant extracts showed moderate larvicidal effects but, the synthesized silver nanoparticles had found to be toxic to larvae at LC50 (0.25 ppm) and LC90 (1 ppm).

关键词： Pongamia pinnata Aedes albopictus Silver Nanoparticle Dengue 9-Octadecenoic Acid (Z)

Forestry Interventions and Groundwater Recharge, Sediment Control and Carbon Sequestration in the Krishna River Basin

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Open Journal of Forestry 2023年第4期13卷 368-395页

作者： Humachadakatte ramachandra swamy Prabuddha Madan Prasad Singh Prathima Purushotham Baragur Neelappa Divakara Tattekere Nanjappa Manohara Basavarajaiah Shivamma Chandrashekar Namasivayam Ravi Nimmala Mohan reddy Ombir Singh Institute of Wood Science and Technology Bengaluru India AgriCapita Innotech Private Limited Bhopal India Forest Research Institute Dehradun India

It is a known fact that human activities have a significant impact on global rivers, making the task of rehabilitating them to their former natural state or a more semi-natural state quite challenging. The ongoing initiative called “Rejuvenation of Krishna River through Forestry Interventions” aims to contribute to the overall river rejuvenation program in the country. In this context, the effects of forestry interventions on the Krishna River will be evaluated based on water quantity, water quality, and the potential for carbon sequestration through plantation efforts. To assess the outcomes of this study, various methodologies such as Soil Conservation Service Curve Number (SCS-CN), Central Ground Water Board (CGWB) and Intergovernmental Panel on Climate Change (IPCC) have been utilized to estimate water savings, reduction in sedimentation, and carbon sequestration potential within the Krishna basin. The projected results indicate that the implementation of forestry plantations and soil and moisture conservation measures in the Krishna River rejuvenation program could lead to significant improvements. Specifically, the interventions are expected to enhance water recharge by 400.49 million cubic meters per year, reduce sedimentation load by 869.22 cubic meters per year, and increase carbon sequestration by 3.91 lakh metric tonnes per year or 14.34 lakh metric tonnes of CO2 equivalent. By incorporating forestry interventions into the Krishna riverscape, it is anticipated that the quality and quantity of water flowing through the river will be positively impacted. These interventions will enhance water infiltration, mitigate soil erosion, and contribute to an improved vegetation cover, thereby conserving biodiversity. Moreover, they offer additional intangible benefits such as addressing climate change concerns through enhanced carbon sequestration potential along the entire stretch of riverine areas.

关键词： Forestry Interventions Krishna River Basin Sediment Control Water Recharge Carbon Sequestration