Proddatūr, India
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Rao K.M.,Yeungnam University | Kumar A.,Yeungnam University | Krishna Rao K.S.V.,Yogivemana University | Haider A.,Yeungnam University | Han S.S.,Yeungnam University
Journal of Polymers and the Environment | Year: 2017

In this article, biodegradable tragacanth gum (TG) biopolymer based silver nanocomposite hydrogels (SNCHs) were prepared with acrylamide as monomer using a simple redox polymerization method. TG acts as stabilizer to produce uniform and large silver nanoparticles (Ag-NPs) in presence of Terminalia chebula (TC) leaf extract in the hydrogel network. Forier transform infrared spectroscopy demonstrated the structural units of functional groups of polymeric backbone of the hydrogels. The formation of Ag-NPs in TG based hydrogels was confirmed by UV–Vis spectra. The morphology of homogeneously dispersed Ag-NPs throughout hydrogel networks was confirmed by scanning electron microscopy. TEM analysis indicates that Ag-NPs with average diameters of around 5 nm formed within the hydrogel networks. The evaluation of antibacterial activity of Ag-NPs performed against gram-negative Escherichia coli and gram-positive Bacillus subtilis bacteria and obtained results proved that these newly developed hydrogels have great potential for use in wound healing as well as water purification applications. © 2017 Springer Science+Business Media New York

Reddy N.B.P.,Minor Irrigation | Reddy M.R.,Yogivemana University
ISH Journal of Hydraulic Engineering | Year: 2015

The effect of convergent angle on the non-uniform flow through porous media was studied in a converging permeameter. The scope of the present paper is to present the relationship between Hydraulic Gradient (I) and Froude Number (FK 2) for flow through porous media with converging boundaries, using intrinsic permeability (K) as characteristic length, and to also show pictorically the relation between linear parameter, a, and non-linear parameter, b, in terms of Media Constant (CW). In the present case, McCorquodale data of size 1.66 cm was used as media, to develop theoretical curves using friction factor (FK) and Reynolds number (RK) relationship, and verified with the help of existing experimental data of different convergent angles. © 2014 Indian Society for Hydraulics.

Rao K.M.,S K University | Mallikarjuna B.,S K University | Krishna Rao K.S.V.,Yogivemana University | Sudhakar K.,k-Technology | And 2 more authors.
International Journal of Polymeric Materials and Polymeric Biomaterials | Year: 2013

Hydrogels were prepared from 2-hydroxy ethyl methacrylate and acrylamidoglycolic acid using N,N-methylene bis acrylamide as a crosslinking agent in presence of potassium persulfate initiator. The average molecular mass between crosslinks (Mc) and polymer-solvent interaction parameter of hydrogels were determined from equilibrium swelling values. Fourier transform infrared spectroscopy of hydrogels shows the confirmation of the formation of co-polymeric hydrogels. Scanning electron microscopy of hydrogels shows the porous network structure. Differential scanning calorimetry and X-ray diffraction were performed to understand the crystalline nature of hydrogel and drug after encapsulation in to hydrogels. In vitro release studies indicated the release of 5-Fluorouracil for more than 12 h. Copyright © 2013 Taylor & Francis Group, LLC.

Kumar A.A.,Yogivemana University | Reddy V.R.,Sri Venkateswara University | Janardhanam V.,Chonbuk National University | Seo M.-W.,Chonbuk National University | And 3 more authors.
Journal of the Electrochemical Society | Year: 2012

We investigated the electrical properties and reverse leakage mechanisms of Pt/n-Ge Schottky contacts with copper phthalocyanine (CuPc) as an interlayer. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the Schottky contacts were used to evaluate Schottky barrier parameters such as ideality factor, barrier height, and series resistance. The barrier heights and ideality factors measured from the forward bias I-V characteristics were found to be 0.50 eV and 1.06 for Pt/n-Ge Schottky contact, and 0.58 eV and 1.31 for Pt/CuPc/n-Ge Schottky contact, respectively. Cheung method was used to measure the series resistances of the Schottky contacts, and the consistency was checked using the Norde method. The reverse leakage conduction mechanism of the Schottky contacts was investigated. Pt/CuPc/n-Ge Schottky contacts showed a transition from Schottky emission to Poole-Frenkel emission at a higher bias range. This could be associated with the high density of structural defects or traps associated with the organic material. © 2011 The Electrochemical Society.

Suresh Babu E.,Koneru Lakshmaiah College of Engineering | Naga Raju C.,Yogivemana University | Krishna Prasad M.H.M.,Andhra University
International Journal of Network Security | Year: 2016

DNA Cryptography is a new cryptographic paradigm from hastily growing bio molecular computation, as its computational power will determine next generation computing. As technology is growing much faster, data protection is getting more important and it is necessary to design the unbreakable encryption technology to protect the information. In this paper, we proposed a biotic DNA based secret key cryptographic mechanism, seeing as DNA computing had made great strides in ultra-compact information storage, vast parallelism, and exceptional energy efficiency. This Biotic Pseudo DNA cryptography method is based upon the genetic information on biological systems. This method makes use of splicing system to improve security, random multiple key sequence to increase the degree of diffusion and confusion which makes resulting cipher texts difficult to decipher and makes to realize a perfect secrecy system. The formal and experimental analysis not only shows that this method is powerful against brute force attack and chosen cipher text attacks, but also it is very efficient in storage, computation as well as transmission.

Madhusudana Rao K.,Sri Krishnadevaraya University | Krishna Rao K.S.V.,Yogivemana University | Sudhakar P.,Sri Krishnadevaraya University | Chowdoji Rao K.,Sri Krishnadevaraya University | Subha M.C.S.,Sri Krishnadevaraya University
Journal of Applied Pharmaceutical Science | Year: 2013

Biodegradable sodium alginate-g-poly (vinyl caprolactam) synthesized by graft copolymerization of N-vinyl caprolactam (VCL) on to sodium alginate (NaAlg) via free radical initiation mechanism using a redox initiation system. Grafting (%), efficiency (%), and conversion (%) were all found to depend on the content of potassium persulfate (KPS), VCL reaction temperature and time. The maximum % of grafting was ascertained to be 251 at the optimum conditions of 65 oC reaction temperature, 180 min of reaction time, 1.1098X10-3 mol of KPS and 7.1844X10-3 mol of VCL. Evidence of graft copolymerization was obtained by fouriertransform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Further, graft copolymer was used for preparation of microgels (MGs) using Ca+2 as a crosslinking agent. SEM results showed that the MGs are spherical in structure with smooth surface. The effects of pH and temperature on the swelling behaviour of MGs were studied and ascertained that they were sensitive to both pH and temperature. 5-FU drug was successfully loaded in to these MGs and encapsulation efficiency was found 84%. The release of 5-FU was systematically investigated as a function of temperature, pH, amount of crosslinker and % of drug loading concentration. The results indicate that the responsive MGs have the potential to be used as an effective pH and temperature controlled delivery of 5-FU for more than 12 h. © 2013 K. Madhusudana Rao et al.

Madhusudana Rao K.,Pusan National University | Krishna Rao K.S.,Yogivemana University | Ramanjaneyulu G.,Sri Krishnadevaraya University | Ha C.-S.,Pusan National University
International journal of pharmaceutics | Year: 2015

Interpenetrating polymeric network nanogels (IPN-NGs) composed of natural gelatin biological protein macromolecules and poly(acrylamidoglycolic acid) were produced by simple free radical emulsion polymerization. The developed IPN-NGs were characterized by Fourier-transform infra-red spectroscopy to confirm the formation of NGs. The hydrophobic curcumin drug was loaded successfully into these NGs using an in-situ method. The curcumin-encapsulated NGs were well dispersed in aqueous solutions and showed good bioavailability. Curcumin was dispersed molecularly in the IPN-NGs, which was confirmed by differential scanning calorimetry and X-ray diffraction. The NGs exhibited pH sensitive properties according to dynamic light scattering and the zeta size potentials. Transmission electron microscopy revealed the NGs to be spherical, approximately 100nm in size. The encapsulation efficiency of these IPN-NGs drug formulations ranged from 42 to 48%. In addition, the release of curcumin from the NGs was examined in phosphate buffer medium. The cytotoxicity of the IPN-NGs was studied using in vitro cultures of fibroblasts and a colorectal cancer cell line. The results suggest that the newly developed pH sensitive gelatin-poly(acrylamidoglycolic acid)-curcumin NGs can be applied for colorectal cancer drug delivery applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Chandra Sekhar E.,Acharya Nagarjuna University | Krishna Rao K.S.V.,Yogivemana University | Ramesh Raju R.,Acharya Nagarjuna University
Journal of Applied Pharmaceutical Science | Year: 2011

Chitosan and guargum-gt-acrylamide (CH-GG-g-AAm) semi interpenetrating microspheres (semi IPNMs) were prepared by water-in-oil (w/o) emulsion cross linking method using glutaraldehyde as a crosslinker. 5-fluorouracil (5-FU) is an anticancer drug was successfully loaded in these semi IPNMs. X-ray diffraction (XRD) and differential scanning calorimetric (DSC) examined the crystalline nature of drug after encapsulation into semi IPNMs. Scanning electron microscopy (SEM) shows the formation of semi IPNMs is spherical with size around 200 ??m. The encapsulation efficiency of 5-FU was achieved 58%. In-vitro release studies were performed basic (pH 7.4) buffer medium. The release patterns depend on graft polymer composition, effect of cross linker and drug content in the polymer matrices. In vitro release studies indicated the release of 5- FU more than 12 hours.

Reddy V.R.,Sri Venkateswara University | Reddy M.S.P.,Sri Venkateswara University | Lakshmi B.P.,Sri Venkateswara University | Kumar A.A.,Yogivemana University
Journal of Alloys and Compounds | Year: 2011

In the present work, we have investigated the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of Au/SiO2/n-GaN metal-insulator-semiconductor (MIS) Schottky diode and compared with Au/n-GaN metal-semiconductor (MS) Schottky diode. Calculations showed that the Schottky barrier height and ideality factor of the MS Schottky diode is 0.79 eV (I-V), 0.87 eV (C-V) and 1.45, respectively. It is observed that the Schottky barrier height increases to 0.86 eV (I-V), 0.99 eV (C-V) and ideality factor deceases to 1.3 for MIS diode. For the MS diode, the calculated doping concentration is 4.17 × 1017 cm-3. However, in the case of the MIS Schottky diode, the decrease in doping concentration is observed and the respective value is 2.08 × 1017 cm-3. The obtained carrier concentration of the MIS diode is reduced about 50% when compared to the MS diode. The interface state density as determined by Terman's method is found to be 3.79 × 1012 and 3.41 × 1010 cm -2 eV-1 for the MS and MIS Schottky diodes, respectively. The calculated interface densities are 2.47 × 1011 cm -2 eV-1, 3.35 × 1011 cm-2 eV-1 and 3.5 × 1011 cm-2 eV-1 for the sweep rates of 300, 450 and 600 mV/s from MOS C-V measurements for the MIS Schottky diode. The interface state density calculated from Terman's method is found to be increased with sweep rate. From the C-V measurement, it is noted that the decrease in the carrier concentration in MIS diodes as compared to MS diode may be due to the presence of oxide interfacial layer. DLTS measurements have also been performed on MIS Schottky diode and discussed. © 2011 Elsevier B.V. All rights reserved.

Ashok Kumar A.,Yogivemana University | Dasaradha Rao L.,Sri Venkateswara University | Rajagopal Reddy V.,Sri Venkateswara University | Choi C.-J.,Chonbuk National University
Current Applied Physics | Year: 2013

We report on the temperature-dependent electrical characteristics of Er/p-InP Schottky barrier diodes. The current-voltage (I-V) and capacitance-voltage (C-V) measurements have been carried out in the temperature range of 300-400 K. Using thermionic emission (TE) theory, the zero-bias barrier height (Φbo) and ideality factor (n) are estimated from I-V characteristics. It is observed that there is a decrease in n and an increase in the Φbo with an increase in temperature. The barrier height inhomogenity at the metal/semiconductor (MS) interface resulted in Gaussian distribution of Φbo and n. The laterally homogeneous Schottky barrier height value of approximately 1.008 eV for the Er/p-InP Schottky barrier diodes is extracted from the linear relationship between the experimental zero-bias barrier heights and ideality factors. The series resistance (R s) is calculated by Chenug's method and it is found that it increases with the decrease in temperature. The reverse-bias leakage current mechanism of Er/p-InP Schottky diode is investigated. Both Poole-Frenkel and Schottky emissions are described and discussed. Furthermore, capacitance-voltage (C-V) measurements of the Er/p-InP Schottky contacts are also carried out at room temperature in dark at different frequencies of 10, 100 and 1000 kHz. Using Terman's method, the interface state density is calculated for Er/p-InP Schottky diode at different temperatures. © 2013 Elsevier B.V. All rights reserved.

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