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Search Results: 1 - 10 of 14163 matches for " Yuvraj Singh Negi "
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Characterization and Biodegradation Studies for Interpenetrating Polymeric Network (IPN) of Chitosan-Amino Acid Beads  [PDF]
Manjusha Rani, Anuja Agarwal, Yuvraj Singh Negi
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2011, DOI: 10.4236/jbnb.2011.21010
Abstract: The paper describes the synthesis of pH sensitive interpenetrating polymeric network (IPN) beads composed of chi-tosan, glycine, glutamic acid, cross linked with glutaraldehyde and their use for controlled drug release. The drug was loaded into beads by varying their composition such as, amount of crosslinker glutaraldehyde, ratio of chitosan, glycine and glutamic acid. The beads were characterized by fourier transform infrared (FTIR) spectroscopy to confirm the cross linking reaction and drug interaction with crosslinked polymer in beads, Scanning Electron Microscopy (SEM) to understand the surface morphology and Differential scanning calorimetry (DSC) to find out the thermal stability of beads. X-Ray Diffraction (XRD) investigation was carried out to determine the crystalline nature of drug after loading into chitosan-glycine-glutamic acid IPN beads. Results indicated amorphous dispersion of chlorpheniramine maleate (CPM) in the polymeric matrix. The swelling behavior of the beads at different time intervals was monitored in solutions of pH 2.0 and pH 7.4. The release experiments were performed in solutions of pH 2.0 and pH 7.4 at 37oC using chlorpheniramine maleate (CPM) as a model drug. The swelling behavior and release of drug were observed to be dependent on pH, degree of cross linking and their composition. The results indicate that the cross linked IPN beads of chitosan-glycine-glutamic acid might be useful as a vehicle for controlled release of drug. The kinetics of drug release from beads was best fitted by Higuchi’s model in which release rate is largely governed by rate of diffusion through the matrix.
Manjusha Rani,Anuja Agarwal,Yuvraj Singh Negi
BioResources , 2010,
Abstract: Chitosan obtained by alkaline deacetylation of chitin is a non-toxic, biocompatible, and biodegradable natural polymer. Chitosan-based hydrogel polymeric beads have been extensively studied as micro- or nano-particulate carriers in the pharmaceutical and medical fields, where they have shown promise for drug delivery as a result of their controlled and sustained release properties, as well as biocompatibility with tissue and cells. To introduce desired properties and enlarge the scope of the potential applications of chitosan, graft copolymerization with natural or synthetic polymers on it has been carried out, and also, various chitosan derivatives have been utilized to form beads. The desired kinetics, duration, and rate of drug release up to therapeutical level from polymeric beads are limited by specific conditions such as beads material and their composition, bead preparation method, amount of drug loading, drug solubility, and drug polymer interaction. The present review summarizes most of the available reports about compositional and structural effects of chitosan-based hydrogel polymeric beads on swelling, drug loading, and releasing properties. From the studies reviewed it is concluded that chitosan-based hydrogel polymeric beads are promising drug delivery systems.
Modification of Poly(ether ether ketone) Polymer for Fuel Cell Application
Devesh Shukla,Yuvraj Singh Negi,Vijai Kumar
Journal of Applied Chemistry , 2013, DOI: 10.1155/2013/386903
Abstract: Polyelectrolyte membrane (PEM) is an important part of PEM fuel cell. Nafion is a commercially known membrane which gives the satisfactory result in PEM fuel cell operating at low temperature. Present research paper includes functionalization of Poly(ether ether ketone) (PEEK) polymer with phosphonic acid group. The functionalization was done with the help of nickel-based catalyst. Further, the polymer was characterized by the FTIR, EDAX, DSC, TGA, and 1H NMR, and it was found that PEEK polymer was functionalized with phosphonic acid group with good thermal stability in comparison to virgin PEEK. Finally, the thin films of functionalized polymer were prepared by solution casting method, and proton conductivity of film samples was measured by impedance spectra whose value was found satisfactory with good thermal stability in comparison to commercially available Nafion membrane. 1. Introduction PEEK is a semicrystalline aromatic polymer having high melting temperature (335°C) and very low or no solubility in ordinary solvents at room temperature. Sulfuric acid is the common solvent which dissolves and also sulfonates PEEK at room temperature. Dilute solutions at high temperatures can also be obtained in hydrofluoric acid, trifluoromethanesulfonic acid, dichlorotetrafluoroacetone monohydrate, phenol 1,2,4-trichlorobenzene, and benzophenone [1]. Therefore, modification of PEEK is typical to some extent but desired for many applications such as polymer electrolyte membrane fuel cell (PEMFC) where acid functionalized polymer is required. In case of PEEK, functionalization in polymer stage is mostly reported on sulfonation and nitration [2]. Phosphonation of polymer is one of the methods to modify their properties such as proton conductivity, mechanical and thermal stability, and in polymer stage it was reported by various groups. Alexandratos et al. [3] reported the phosphonation of polystyrene using PCl3 which gave the cross-linked polymer. However, Jakoby et al. [4] reported that the highly substituted phosphonic acid derivative of polyphenylsulfone (PPS) was achieved via the Pd-dibenzylideneacetone (dba) complexed catalyst in solvent diphenyl ether. Increase of reaction temperature from 90°C to 120°C also enhanced the substitution level. Bock et al. [5] reported phosphonation of the polysulfones (PSU) using nickel chloride and silylated phosphonates. The route was found less expensive and gave the halogen free product in comparison to palladium-based catalytic route. Lafitte and Jannasch [6] reported a phosphonation of polysulfones via the lithiation of
Pradeep Kumar,Yuvraj Singh Negi,Surendra Pal Singh
BioResources , 2011,
Abstract: Standard handsheets of bleached bagasse and hardwood pulps were prepared with calcium carbonate filler loading by conventional method and by in-situ precipitation. The handsheets were printed with an IGT printability tester. The effect of filler loading by in-situ precipitation on ink transfer, print density, and print-through was studied. For a given amount of ink on the printing disk or on the paper, the print density was greater and the print-through was less for in-situ precipitation of filler when compared with the conventional filler loading.
Pradeep Kumar,Yuvraj Singh Negi,Surendra Pal Singh
BioResources , 2011,
Abstract: A review of the literature reveals potential advantages that papermakers can achieve by placing minerals in the lumens or cell walls of fibers before the pulp is formed into paper. Loading of filler into the fiber lumen by mechanical deposition or within the cell wall by in-situ precipitation has been reported to generally result in a moderate reduction in light scattering coefficient and increased strength properties of laboratory handsheets, as well as in paper manufactured with pilot plant equipment, when compared to conventional addition of filler. However, there are some exceptions to this general observation, where the fiber loading is reported to decrease the tensile strength of paper. Some related effects can be achieved by either precipitating mineral onto fiber surfaces or co-flocculating mineral particles with cellulosic fines. Challenges remain with respect to the implementation of fiber-loading concepts at a commercial scale. Also, there is a need for further research aimed at establishing high-end applications in which it may be an advantage to load cellulosic fiber cell walls or lumens with minerals or other substances.
A Large Celiac Artery Aneurysm  [PDF]
Harinder Singh Bedi, Kamal Negi
World Journal of Cardiovascular Surgery (WJCS) , 2013, DOI: 10.4236/wjcs.2013.33019
Abstract: We report preoperative, intraoperative and postoperative images of a large celiac artery aneurysm.
The “Bedi-IMA Buttress”: Reinforcement of the Bronchial Stump with a Pedicled Internal Mammary Artery Buttress in Diabetic Patients after Lung Resection  [PDF]
Harinder Singh Bedi, Kamal Negi
World Journal of Cardiovascular Surgery (WJCS) , 2014, DOI: 10.4236/wjcs.2014.412032
Abstract: Objective: The development of a bronchopleural fistula is a devastating complication after lung resection. We describe a new method of buttressing the closure of the stump in diabetic patients using a pedicled internal mammary artery buttress flap to avoid a bronchopleural fistula. Methods: An internal mammary pedicled flap was used in 14 diabetic patients of lung resection to cover the bronchial stump. Results: The flap of viable vascularized muscle mass gave an excellent coverage of the bronchial stump. All patients recovered well with no bronchopleural fistula. Conclusions: We recommend this technique as a method of buttressing the bronchial stump in cases of lung resection, as the internal mammary artery is easily available and its use is not associated with any side effects.
Detection, Identification and Characterization of Staphylococci in Street Vend Foods—Characterization of Staphylococcus Isolates  [PDF]
Rohinishree Yadahalli Shrihari, Pradeep Singh Negi
Food and Nutrition Sciences (FNS) , 2011, DOI: 10.4236/fns.2011.24044
Abstract: In the present investigation the diversity of the Staphylococcus species in different street vend food samples was studied. A total of 35 staphylococcal food isolates comprising of various species from 14 different street vend food samples were identified and characterized phenotypically. Staphylococcus aureus was found to be the most prevalent species in these foods. A PCR-RFLP analysis based on 16S rRNA gene was used for identification of Staphylococcus species. Isolates showing distinct RFLP pattern for AluI restriction digestion were selected for nucleotide sequence analysis. Phylogenetic tree constructed using the multiple alignments of 16S rRNA gene sequences of isolates showed a hotspot region of 169 bp and the relationship among species was evaluated by bootstrap values generated in phylogenetic analysis. 16S rRNA gene sequences allowed bacterial identification that was reproducible and more accurate than that obtained by phenotypic testing. 16S rRNA gene sequence analysis would be helpful in timely and correct identification of pathogens.
Cloud Business Intelligence – Is What Business Need Today
Yuvraj Singh Gurjar,Vijay Singh Rathore
International Journal of Recent Technology and Engineering , 2013,
Abstract: The present economic crisis experienced by all the states of the world orients more and more the information technology industry towards efficiency. Organizations are striving to become intelligent and achieve competition advantages through the use of Business Intelligence (BI) solutions. One of the instruments that can bring about the technology requirements of evolving BI solutions is Cloud Computing. The present paper identifies the key factors responsible for evolution of New Business Intelligence on the Cloud, the various models available to port BI solution on Cloud, the primary drivers for Cloud BI, the impact of implementing Cloud BI as well as issues around it.
Electron Monopole Duality in Quantum Hall Effect  [PDF]
Pawan Ku. Joshi, Praveen Singh Bisht, Om Prakash Singh Negi
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2011, DOI: 10.4236/jemaa.2011.31004
Abstract: Starting from the duality between electric and magnetic field, we have made an attempt to discuss the quantum hall effect from the consideration of magnetic monopole in view of electron monopole duality. Starting from the dual dy-namics of electric and magnetic charges, we have reformulated a consistent theory of quantum hall effect in presence of monopole. Speculating the existence of magnetic monopoles in magnetic materials (metals), we have accordingly modi-fied the parameters; like drift velocity, current density, Hamiltonian and eigen values and eigen function for harmonic oscillator; resposible to examine the quantum Hall effect in metals.
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