A novel method for the preparation of silver/chitosan-O-methoxy polyethylene glycol core shell nanoparticles

Journal of Catalysis 246 (2007) 362–369 www.elsevier.com/locate/jcat A novel method for the synthesis of titania nanotubes using sonoelectrochemical method and its application for photoelectrochemical splitting of water S.K. Mohapatra, M. Misra ∗ , V.K. Mahajan, K.S. Raja Materials Science and Metallurgical Engineering, MS 388, University of Nevada, Reno, NV 89557, USA Received 2 October 2006; revised 18 December 2006; accepted 27 December 2006 Available online 25 January 2007 Abstract This new method describes the application of sonoelectrochemistry to quickly synthesize well-ordered and robust titanium dioxide (TiO 2 ) nanotubular arrays. Self-ordered arrays of TiO 2 nanotubes of 30–100 m in diameter and 300–1000 nm in length can be rapidly synthesized under an applied potential of 5–20 V. The rate of formation of the TiO 2 nanotubes by the sonoelectrochemical method is found to be almost twice as fast as the magnetic stirring method. It also demonstrates that high-quality nanotubes can be prepared using high viscous solvents like ethylene glycol under ultrasonic treatment. The TiO 2 nanotubes prepared in the organic electrolytes (ethylene glycol) are then annealed under H 2 atmosphere to give TiO 2−x C x types material having a band gap of around 2.0 eV. This process is found to be highly efficient for incorporating carbon into TiO 2 nanotubes. Various characterization techniques (viz., FESEM, GXRD, XPS, and DRUV–vis) are used to study the morphology, phase, band gap, and doping of the nanotubes. The photoelectrocatalytic activity of these materials to generate H 2 by water splitting is found to be promising at 0.2 V vs Ag/AgCl. © 2007 Elsevier Inc. All rights reserved. Keywords: TiO 2 nanotubes; Sonoelectrochemistry; Photoelectrocatalysis; Water splitting 1. Introduction Titania (TiO 2 ) is well known as a semiconductor with photo- catalytic activities and has great potential in many areas, includ- ing environmental purification, gas sensors, photovoltaics, im- mobilization of biomolecules, and generation of hydrogen gas [1–12]. Over the past several years, preparation of TiO 2 nan- otubes by the anodization process has caught the attention of the scientific community due to its one-dimensional nature, ease of handling, and simple preparation. Over the years, several electrolytic combinations have been used for the anodization of titanium [13–18]. The anodization of titanium using phos- phoric acid and sodium fluoride or hydrofluoric acid has also recently been reported [19]. However, the reported titania nan- otubes are not well ordered, and it takes several hours to make * Corresponding author. E-mail address: misra@unr.edu (M. Misra). micron-length nanotubes in a high-pH electrolyte. This pa- per presents a novel sonoelectrochemical technique to anodize titania—anodization under irradiation of ultrasonic waves— which quickly leads to the synthesis of well-ordered titania nan- otubes. The anodization approach builds self-organized titania nanotubular arrays of controllable tube diameter, good unifor- mity, and conformability over large areas. Sonochemistry is widely used for catalysis, electrochem- istry, food technology, synthesis of nanomaterials, and water purification, and other applications [20]. Sonochemistry works through generation and subsequent destruction of cavitation bubbles. Collapse of a cavitation bubble on or near to a solid surface generates Appl Nanosci (2014) 4:113–119 DOI 10.1007/s13204-012-0180-y ORIGINAL ARTICLE A novel green one-step synthesis of silver nanoparticles using chitosan: catalytic activity and antimicrobial studies Maragoni Venkatesham • Dasari Ayodhya Alle Madhusudhan • Nagati Veera Babu • Guttena Veerabhadram • Received: 19 October 2012 / Accepted: 22 November 2012 / Published online: 16 December 2012 Ó The Author(s) 2012 This article is published with open access at Springerlink.com Abstract Stable silver nanoparticles were synthesized using chitosan acting as both reducing and stabilizing agent without using any toxic chemicals This reaction was carried out in an autoclave at a pressure of 15 psi and 120 °C temperature by varying the time The influence of different parameters such as time, change of concentration of silver nitrate and concentration of chitosan on the formation of silver nanoparticles were studied The synthesized silver nanoparticles were characterized by UV–visible spectroscopy, Fourier transform infrared, X-ray diffraction and transmission electron microscopy The results of catalytic reduction of 4-nitrophenol by sodium borohydride in the presence of green synthesized silver nanoparticles were presented The antimicrobial activity of silver nanoparticles was tested against Escherichia coli and Micrococcus luteus and was found to be possessing inhibiting property Keywords Green synthesis Á Chitosan Á Autoclave Á Nanosilver Á Catalysis and antimicrobial activity Introduction Metallic nanoparticles have been widely studied in recent years because of their potential use as catalysts (Chimentao et al 2004; Gong and Mullins 2009; Campelo et al 2009; Li et al 2010) Silver nanoparticles are of particular M Venkatesham Á D Ayodhya Á A Madhusudhan Á G Veerabhadram (&) Department of Chemistry, Osmania University, Hyderabad 500007, India e-mail: gvbhadram@gmail.com N Veera Babu Department of Biochemistry, Osmania University, Hyderabad 500007, India interesting due to their role as substrates in the studies of catalysis (Tsujino and Matsumura 2005; Shimizu et al 2010), surface enhancement, Raman spectroscopy (Debarre et al 2004; Terekhov et al 2011) and in the biomedical field (Xu et al 2006; Liu et al 2010; Krishna Rao et al 2012) Because of their vast applications in various fields, many techniques of synthesizing silver nanoparticles have been investigated and some of them are: chemical reduction (Bhui and Misra 2012), electrochemical reduction (Starowicz et al 2006; Hosseini and Momeni 2010), photochemical reduction (Kutsenko and Granchak 2009), microemulsion (Zhang et al 2011), gamma-ray irradiation (Huang et al 2009; Rao et al 2010), UV irradiation (Spadaro et al 2010), ultrasonic method (Byeon and Kim 2012), microwave method (Nadagouda et al 2011), etc Different varieties of stabilizers have been used in silver nanoparticles preparation, as mentioned above, to achieve the best control of size, distribution, shape, stability and solubility of silver nanoparticles The most commonly used stabilizers are polyvinyl pyrrolidone (PVP) (Link et al 1999; Tan et al 2003), polyvinyl alcohol (PVA) (Abdul kareem and Anu kaliani 2011), polyaniline (Bouazza et al 2009) and polyethylene glycol (PEG) (Tan et al 2003) Natural polymers have also been used in the preparation of nanosilver because they are nontoxic and biocompatible Starch (Hu et al 2008) and chitosan (Hettiarachchi and Wickramarachchi 2011) have been used as stabilizers for the preparation of metal nanoparticles Many of the nanoparticle synthesis methods, however, involve use of hazardous chemicals, low material conversions and high energy requirements Over past decade, keen interest has been evinced in green synthesis Green synthesis is costeffective, environment friendly, easily scaled up for largescale synthesis and also there is no need to use toxic chemicals 123 114 Appl Nanosci (2014) 4:113–119 Chitosan is a biodegradable polysaccharide copolymer of N-acetyl-D-glucosamine and D-glucosamine, obtained by the alkaline deacetylation of chitin (Onishi and Machida 1999) It is considered as a nontoxic, biodegradable, biocompatible and environmental-friendly material with many superior properties (Jigar and Sinha 2007) It is the second most plentiful natural biopolymer and is relatively cheap (Ma et al 2008) In this paper, we report the green synthesis of silver nanoparticles using chitosan as both reducing and stabilizing agent and without using any toxic chemicals This reaction is carried out in an autoclave at a pressure of 15 psi and at 120 °C temperature by varying the time The influence of different parameters such as time, change of concentration of silver nitrate and concentration of chitosan on the formation of silver nanoparticles was studied In recent days, nitro aromatic compounds are widely used in chemical industries These are xenobiotics, used in manufacturing of pesticides, dyes, plasticizers, fungicides and explosives These anthropogenic compounds ...Journal of Applied Chemical Research, 7, 4, 39-49 (2013) Journal of Applied Chemical Research www.jacr.kiau.ac.ir A Novel Method for the Synthesis of CaO Nanoparticle for the Decomposition of Sulfurous Pollutant Meysam Sadeghi *1 , Mir Hassan Husseini 2 1,2 Department of Chemistry, Faculty of Sciences, Imam Hussein Comprehensive University, Tehran, Iran. 2 Nano Center Research, Imam Hussein Comprehensive University, Tehran, Iran. Received 03 Jun. 2013; Final version received 09 Aug. 2013 Abstract In this research, CaO (calcium oxide) nanoparticles were synthesized by Co-Precipitation method in the absence and presence of Polyvinylpyrrolidone (PVP) via using calcium (II) nitrate. The Polyvinylpyrrolidone (PVP) was used as a capping agent to control the agglomeration of the nanoparticles. The synthesized samples were characterized via SEM, XRD and FTIR techniques. The average sizes of nanoparticles were determined by XRD data and Scherer equation. The decomposition reactions of 2-chloroethyl phenyl sulde (2-CEPS) as a sulfurous pollutant has been investigated on the CaO nanoparticles (NPs)/ Polyvinylpyrrolidone (PVP) surface at ambient temperature and monitored via using gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and FTIR spectrum. The GC analysis results revealed that 75% and 100% of 2-CEPS was found to be decomposed (adsorbed/destructed) in isopropanol and heptane solvents with weight ratio of 1:40(2-CEPS: CaO) after 12 h, respectively. On the other hand, these values for the weight ratios of 1:10, 1:20 and 1:30 were lower. The hydrolysis and elimination products; i.e. hydroxyl ethyl phenyl sulde (HEPS) and phenyl vinyl sulde (PVS) were identied by GC-MS respectively. Keywords: CaO (calcium oxide) nanoparticles, Co-Precipitation, Polyvinylpyrrolidone (PVP), 2-CEPS, Decomposition, Adsorbed/destructed. * Corresponding author: Meysam Sadeghi, Department of Chemistry, Faculty of Sciences, Imam Hussein Comprehensive University, Tehran, Iran. Email: meysamsadeghi45@yahoo.com, Tel +9809375117746, Fax 02177104930. Introduction The 2-chloroethyl phenyl sulde (2-CEPS) is for the class of compounds containing sulfurous pollutant with the highly toxic that used such as pesticides, poses inevitable threat to persons who make contact; thereby causing M. Sadeghi et al., J. Appl. Chem. Res., 7, 4, 39-49 (2013) 40 health hazards [1-6]. The different methods are for decomposition and elimination of these compounds [7-9]. A series of materials including, bleach, potassium per sulfate, ozone, sodium per borate were used as active adsorbents along with surfactants in micro- emulsions for detoxication of pesticides [1]. Certain disadvantages exist with the use of these adsorbents such as environmental contaminates. In recent years, nanocrystalline inorganic metal oxides as solid reactive catalyst sorbents instead of liquid adsorption media were investigated [10 14]. Strong adsorbs ability and enhanced reactivity towards the toxicants makes them the potential materials for the decomposition applications. These intriguing properties within the above materials are expected to be aroused owing to the high surface area due to smaller particle size and the reactive sites tailored in the form of edge and corner defects, unusual lattice planes, etc. Most likely, these active sites react in a stoichiometric fashion, thereby rendering the adsorbed toxic agents to non-toxic ones and Jähn et al. Journal of Orthopaedic Surgery and Research 2010, 5:32 http://www.josr-online.com/content/5/1/32 Open Access TECHNICAL NOTE BioMed Central © 2010 Jähn et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons At- tribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Technical Note A rapid method for the generation of uniform acellular bone explants: a technical note Katharina Jähn 1,2 , Volker Braunstein 3 , Pamela I Furlong 1 , Angharad E Simpson 1 , R Geoff Richards 1,2 and Martin J Stoddart* 1 Abstract Background: Bone graft studies lack standardized controls. We aim to present a quick and reliable method for the intra-operative generation of acellular bone explants. Methods: Therefore, ovine cancellous bone explants from the iliac crest were prepared and used to test several methods for the induction of cell death. Over night heat inactivation was used as positive treatment control, methods to be investigated included UV light, or X- ray exposure, incubation in a hypotonic solution (salt-free water) and a short cycle of repeated freezing and thawing. Results: Viability of treated and 2 days cultured bone explants was investigated by lactate dehydrogenase assay. Non- treated cultured control explants maintained around 50% osteocyte viability, while osteocyte survival after the positive treatment control was abolished. The most dramatic loss in cell viability, together with a low standard deviation, was a repeated cycle of freezing and thawing. Conclusions: To summarize, we present a freeze-thaw method for the creation of acellular bone explants, which is easy to perform, not time-consuming and provides consistent results. Background Large bone defects remain a clinical challenge and the development of novel therapies requires adequate con- trols. The use of acellular bone explants within bone graft studies is of crucial importance [1]. Results of trans- planted bone material can not be interpreted correctly without the presence of a bone matrix control which does not contain viable cells. It is well known that the success of bone grafts is determined by three factors - osteoin- duction, osteoconductivity and osteogenesis [1]. The concept of osteoinduction involves mitogenesis of undif- ferentiated host mesenchymal stem cells towards the for- mation of osteoprogenitors by i.e. molecules of the TGFβ family which are stored in huge amounts within bone matrix [2]. Osteoconductivity is achieved when the implanted bone is used by the host cells as scaffold for the formation of new bone. An acellular bone explant control aids to evaluate the effects of active bone cells (osteogen- esis) versus the effect of the bone matrix alone (osteoin- duction and osteoconductivity) during bone transplantation studies. Unfortunately, a reliable control with a uniformly diminished cell survival is not standard- ized yet. Acellular bone grafts are often prepared using γ-irradi- ation or ethylene oxide sterilization of allogenic bone explant material [3]. Yet, both methods have been shown to reduce the mechanical properties of R74 Introduction The pathology of rheumatoid arthritis (RA) is characterized by the infiltration of several inflammatory cells into both the pannus and the joint fluid, and by subsequent tissue destruction. Chemokines, as well as other inflammatory mediators, appear to play key roles in the pathogenesis of RA, and the co-ordinated production of chemokines and proinflammatory cytokines is probably important in the orchestration of the inflammatory responses observed in patients with RA [1–4]. Chemokines belong to a gene superfamily of chemotactic cytokines that share substantial homology with four con- served cysteine amino acid residues [5–7]. The CXC family of chemokines (e.g. interleukin-8, growth-related oncogene, and epithelial cell-derived neutrophil attractant-78), in which the first two cysteines are sepa- rated by another amino acid residue, is chemotactic for neutrophils and T cells. The CC chemokine family (e.g. macrophage inflammatory protein-1, macrophage chemoattractant protein-1, and RANTES [regulated upon activation, normal T-cell expressed and secreted]), in which the first two cysteine residues are juxtaposed, is chemotactic for monocytes and subpopulations of T cells. IFN-γ inducible protein-10 (IP-10), a member of the CXC chemokine family, is expressed and secreted by mono- cytes, fibroblasts, and endothelial cells after stimulation with IFN-γ [5,8], and has important roles in the migration of FLS = fibroblast-like synoviocyte; ICAM = intercellular adhesion molecule; IFN = interferon; IP-10 = IFN-γ inducible protein-10; OA = osteoarthritis; PMN = polymorphonuclear neutrophil; PCR = polymerase chain reaction; RA = rheumatoid arthritis; RT = reverse transcription; SF = synovial fluid; Th = T-helper (cell); TNF = tumor necrosis factor. Arthritis Research & Therapy Vol 5 No 2 Hanaoka et al. Research article A novel mechanism for the regulation of IFN- γγ inducible protein-10 expression in rheumatoid arthritis Ryosuke Hanaoka 1 , Tsuyoshi Kasama 1 , Mizuho Muramatsu 1 , Nobuyuki Yajima 1 , Fumitaka Shiozawa 1 , Yusuke Miwa 1 , Masao Negishi 1 , Hirotsugu Ide 1 , Hideyo Miyaoka 2 , Hitoshi Uchida 3 and Mitsuru Adachi 1 1 Division of Rheumatology and Clinical Immunology, First Department of Internal Medicine, Showa University School of Medicine, Tokyo, Japan 2 Department of Orthopedics, Showa University School of Medicine, Tokyo, Japan 3 Department of Orthopedics, Furukawabashi Hospital, Tokyo, Japan Corresponding author: Tsuyoshi Kasama (e-mail: tkasama@med.showa-u.ac.jp) Received: 22 August 2002 Revisions received: 7 November 2002 Accepted: 12 November 2002 Published: 6 January 2003 Arthritis Res Ther 2003, 5:R74-R81 (DOI 10.1186/ar616) © 2003 Hanaoka et al., licensee BioMed Central Ltd (Print ISSN 1478-6354; Online ISSN 1478-6362). This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any non-commercial purpose, provided this notice is preserved along with the article's original URL. Abstract Chemokines play an essential role in the progression of rheumatoid arthritis (RA). In the present study we examined the expression and regulatory mechanisms of IFN-γ inducible protein (IP)-10 in RA synovitis. RA synovial fluid contained greater amounts of IP-10 than did synovial fluid from patients with osteoarthritis. Immunolocalization analysis indicated that IP-10 was associated mainly with infiltrating macrophage-like cells, and fibroblast-like cells in the RA synovium. The interaction of activated leukocytes with fibroblast-like synoviocytes resulted in marked increases in IP-10 expression and secretion. Moreover, induction of IP-10 was mediated via specific adhesion molecules, as indicated by the finding that both anti-integrin (CD11b and CD18) and intercellular adhesion molecule-1 antibodies significantly inhibited IP-10 induction. These results suggest that IP-10 expression within inflamed joints appears to be regulated not only by inflammatory The University of Toledo The University of Toledo Digital Repository Theses and Dissertations 2013 A novel algorithm for the reconstruction of an entrance beam fluence from treatment exit patient portal dosimetry images Nicholas Niven Sperling The University of Toledo Follow this and additional works at: http://utdr.utoledo.edu/theses-dissertations Recommended Citation Sperling, Nicholas Niven, "A novel algorithm for the reconstruction of an entrance beam fluence from treatment exit patient portal dosimetry images" (2013) Theses and Dissertations Paper 214 This Dissertation is brought to you for free and open access by The University of Toledo Digital Repository It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of The University of Toledo Digital Repository For more information, please see the repository's About page A Dissertation entitled A Novel Algorithm for the Reconstruction of an Entrance Beam Fluence from Treatment Exit Patient Portal Dosimetry Images by Nicholas Niven Sperling Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Physics Dr E Ishmael Parsai, Committee Chair Dr Patricia R Komuniecki, Dean College of Graduate Studies The University of Toledo December 2013 Copyright 2013, Nicholas Niven Sperling This document is copyrighted material Under copyright law, no parts of this document may be reproduced without the expressed permission of the author An Abstract of A Novel Algorithm for the Reconstruction of an Entrance Beam Fluence from Treatment Exit Patient Portal Dosimetry Images by Nicholas N Sperling Submitted to the Graduate Faculty as partial fulfillment of the requirements for the Doctor of Philosophy Degree in Physics The problem of determining the in vivo dosimetry for patients undergoing radiation treatment has been an area of interest since the development of the field Most methods which have found clinical acceptance work by use of a proxy dosimeter, e.g.: glass rods, using radiophotoluminescence; thermoluminescent dosimeters (TLD), typically CaF or LiF; Metal Oxide Silicon Field Effect Transistor (MOSFET) dosimeters, using threshold voltage shift; Optically Stimulated Luminescent Dosimeters (OSLD), composed of Carbon doped Aluminum Dioxide crystals; RadioChromic film, using leuko-dye polymers; Silicon Diode dosimeters, typically p-type; and ion chambers More recent methods employ Electronic Portal Image Devices (EPID), or dosimeter arrays, for entrance or exit beam fluence determination The difficulty with the proxy in vivo dosimetery methods is the requirement that they be placed at the particular location where the dose is to be determined This precludes measurements across the entire patient volume These methods are best suited where the dose at a particular location is required The more recent methods of in vivo dosimetry make use of detector arrays and reconstruction techniques to determine dose throughout the patient volume One method uses an array of ion chambers located upstream of the patient This requires a special iii hardware device and places an additional attenuator in the beam path, which may not be desirable A final approach is to use the existing EPID, which is part of most modern linear accelerators, to image the patient using the treatment beam Methods exist to deconvolve the detector function of the EPID using a series of weighted exponentials (1) Additionally, this method has been extended to determine in vivo dosimetry The method developed here employs the use of EPID images and an iterative deconvolution algorithm to reconstruct the impinging primary beam fluence on the patient This primary fluence may then be employed to determine dose through the entire patient volume The method requires patient specific information, including a CT for deconvolution/dose reconstruction With the large-scale adoption of Cone Beam CT (CBCT) systems on modern linear accelerators, a ... (Panalytical B.V., Netherlands) operating at 40 kV and a current of 30 mA at a scan rate of 0.388 min-1 The size distribution and crystallinity of the silver nanoparticles stabilized in chitosan... range of 410–430 nm, a typical plasmon resonance band of silver nanoparticles There are no peaks located around 335 and 560 nm, indicating the absence of nanoparticle aggregation The reduction was... due to the formation of the 4-nitrophenolate ion (Pradhan et al 2001) The anionic silver species remain stable for weeks in the absence of any other reagent After adding nanoparticles stabilized