A versatile characterization of poly(N-isopropylacrylamide-co-N,N'-methylene-bis-acrylamide hydrogels for composition, mechanical strength, and rheology

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J. Kovacs

2013-01-01

Full Text Available Poly(N-isopropylacrylamide-co-N,N'-methylene-bisacrylamide (P(NIPAAm-co-MBA hydrogels were prepared in water using redox initiator. The copolymer composition at high conversion (> 95% was determined indirectly by HPLC (high performance liquid chromatography analysis of the leaching water and directly by solid state 13C CP MAS NMR (cross polarization magic angle spinning nuclear magnetic resonance spectroscopy of the dried gels, and was found to be close to that of the feed. The effect of cross-linker (MBA content in the copolymer was investigated in the concentration range of 1.1–9.1 mol% (R:90–10; R = mol NIPAAm/mol MBA on the rheological behaviour and mechanical strength of the hydrogels. Both storage and loss modulus decreased with decreasing cross-linker content as revealed by dynamic rheometry. Gels R70 and R90 with very low cross-linker content (1.2–1.5 mol% MBA have a very loose network structure, which is significantly different from those with higher cross-linker content manifesting in higher difference in storage modulus. The temperature dependence of the damping factor served the most accurate determination of the volume phase transition temperature, which was not affected by the cross-link density in the investigated range of MBA concentration. Gel R10 with highest cross-linker content (9.1 mol% MBA behaves anomalously due to heterogeneity and the hindered conformation of the side chains of PNIPAAm.

Estructura cristalina del N-isopropil-2-ciano-3(5'-nitrofurilacrilamida Crystal structure of N-isopropyl-2-cyano-3(5'-nitrofurylacrylamide

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Ramón Pomés Hernandéz

1997-12-01

Full Text Available C11H11N3O4 , Mr = 249.23, triclinic, , a = 5.453(1, b = 22.873(5, c = 4.893(1 Å, a = 94.47(3, b = 96.36(3, g = 86.27(3º, V = 603.7(8ų,Z = 2, Dx = 1.371 Mg/m-3,l(Cu Ka1 = 1.54178Å, m = 0.86mm-1, room temperature. The crystal structure of N-isopropyl-2-cyano-3(5'-nitrofuryl - acrylamide has been determined by Direct Methods and refined to R = 0.086 for 797 observed reflections. The molecules in the crystal are packed at normal van der Waals forces and by an hydrogen bond between N1-H1...02i (N1...02i: 2.910(1Å, with i=x,y,z+1.

Drug delivery system prepared by ionizing radiation of the N,N-dimethyl acrylamide with acryloyloxy-acetanilide copolymerization

International Nuclear Information System (INIS)

Martellini, Flavia; Higa, Olga Z.; Queiroz, Alvaro A.A. de; Rodighiero, Paolo

1995-01-01

Radiation induced polymerization has been used in biomaterials used in systems which such as drug delivery (DDS). This work describes the copolymerization of the monomers by gamma rays N,N-dimethyl acrylamide (DMAA) and acryloyloxy-acetanilide (AOA) for the immobilization of paracetamol, an analgesic and anti thermic drug. Dimethylformamide solutions were used in two concentrations of DMAA and AOA (F DMAA/AOA = 0,85/015 and 0,70/0,30, where F = molar fraction in the monomer feed). The samples were irradiated in the dose range of 30-800 Gy. The copolymer poly(DMAA-co-AOA) characterization was carried out by FTIR and 1 HRMN. The hydrolysis was studied considering the formation of sodium salts of 4-hydroxy acetanilide at different times of treatment using colorimetric assay. (author). 6 refs., 5 figs

Semi-interpenetrating networks based on POLY(N-isopropyl acrilamide and POLY(N-vinylpyrrolidone

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Žugić Dragana

2007-01-01

Full Text Available Three series of semi-interpenetrating polymer networks based on cross-linked poly(N-isopropylacrylamide, PNIPA, and 1, 2 and 3 wt% of linear poly(N-vinylpyrrolidone, PVP, were synthesized in order to improve the mechanical properties of PNIPA gels. The effect of the incorporation of the linear PVP polymer into the temperature responsive networks on the phase transition temperature, swelling behavior and mechanical properties was studied. Polymer networks with four different crosslinking densities were prepared with various molar ratios (25/1 to 100/1 of the monomer (N-isopropylacrylamide to the cross linker (N,N'-methylene-bisacrylamide. The hydrogels were characterized by determination of the equilibrium degree of swelling at 25 °C, the dynamic shear modulus and the effective crosslinking density, as well as the ultimate hydrogel properties, such as the tensile strength and elongation at break. Furthermore, the deswelling kinetics of the hydrogels was also studied by measuring their water retention capacity. The inclusion of the linear hydrophilic PVP in the PNIPA networks increased the equilibrium degree of swelling, the highest values of which were obtained for samples with 2 and 3 wt% of PVP and the NIPA/MBA molar ratio of 75/1 and 100/1. The highest reinforcement effect, evaluated from the ratio of G'red(semi-IPN to G'red(PNIPA, was obtained by incorporation of 2 wt% PVP. The tensile strength of the semi-IPNs reinforced with linear PVP was higher than that of the PNIPA networks. The elongation at break of these semi-IPNs varied between 22 and 55%, which are 22^11% larger than those for single PNIPA networks. The tensile measurements confirmed that the presence of 2 wt% of the linear polymer significantly reinforced the PNIPA network.

Poly(n-isopropylacrylamide)-based hydrogel coatings on magnetite nanoparticles via atom transfer radical polymerization

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Frimpong, Reynolds A; Hilt, J Zach [Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States)], E-mail: hilt@engr.uky.edu

2008-04-30

Core magnetite (Fe{sub 3}O{sub 4}) nanoparticles have been functionalized with a model intelligent hydrogel system based on the temperature responsive polymer poly(n-isopropyl acrylamide) (PNIPAAm) to obtain magnetically responsive core-shell nanocomposites. Fe{sub 3}O{sub 4} nanoparticles were obtained from a one-pot co-precipitation method which provided either oleic acid (hydrophobic) or citric acid (hydrophilic) coated nanoparticles. Subsequent ligand exchange of these coatings with various bromine alkyl halides and a bromo silane provided initiating sites for functionalization with NIPAAm using atom transfer radical polymerization (ATRP). The bromine alkyl halides that were used were 2-bromo-2-methyl propionic acid (BMPA) and 2-bromopropionyl bromide (BPB). The bromo silane that was used was 3-bromopropyl trimethoxysilane (BPTS). The intelligent polymeric shell consists of NIPAAm crosslinked with poly(ethylene glycol) 400 dimethacrylate (PEG400DMA). Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) were used to confirm the presence of the polymeric shell. Dynamic light scattering (DLS) was used to characterize the nanocomposites for particle size changes with temperature. Their magnetic and temperature responsiveness show great promise for further biomedical applications. This platform for functionalizing magnetic nanoparticles with intelligent hydrogels promises to impact a wide range of medical and biological applications of magnetic nanoparticles.

Poly(n-isopropylacrylamide)-based hydrogel coatings on magnetite nanoparticles via atom transfer radical polymerization

International Nuclear Information System (INIS)

Frimpong, Reynolds A; Hilt, J Zach

2008-01-01

Core magnetite (Fe 3 O 4 ) nanoparticles have been functionalized with a model intelligent hydrogel system based on the temperature responsive polymer poly(n-isopropyl acrylamide) (PNIPAAm) to obtain magnetically responsive core-shell nanocomposites. Fe 3 O 4 nanoparticles were obtained from a one-pot co-precipitation method which provided either oleic acid (hydrophobic) or citric acid (hydrophilic) coated nanoparticles. Subsequent ligand exchange of these coatings with various bromine alkyl halides and a bromo silane provided initiating sites for functionalization with NIPAAm using atom transfer radical polymerization (ATRP). The bromine alkyl halides that were used were 2-bromo-2-methyl propionic acid (BMPA) and 2-bromopropionyl bromide (BPB). The bromo silane that was used was 3-bromopropyl trimethoxysilane (BPTS). The intelligent polymeric shell consists of NIPAAm crosslinked with poly(ethylene glycol) 400 dimethacrylate (PEG400DMA). Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) were used to confirm the presence of the polymeric shell. Dynamic light scattering (DLS) was used to characterize the nanocomposites for particle size changes with temperature. Their magnetic and temperature responsiveness show great promise for further biomedical applications. This platform for functionalizing magnetic nanoparticles with intelligent hydrogels promises to impact a wide range of medical and biological applications of magnetic nanoparticles

Synthesis and toxicity of poly (2-hydroxyethyl methacrylate-co-acrylamide) hydrogels obtained by gamma photon irradiation

International Nuclear Information System (INIS)

Rapado, Manuel; Vernhes, Marioly; Peniche, Carlos

2016-01-01

In this paper is reported the obtaining of hydrogels from poly hydroxyethyl methacrylate-co-acrylamide, by simultaneous crosslinking copolymerization from corresponding monomers by gamma photon irradiation. The composition of network chains in the copolymer was estimated from elemental analysis and infrared spectroscopy. Additionally, the toxicity of these materials was tested finding the free acrylamide and biological assay SOS in bacteria. The extracts of washed matrices of copolymers showed low level of free acrylamide. Moreover, they were non toxic on the E. coli cells tested at any time. (author)

Design and synthesis study of the thermo-sensitive poly (N-vinylpyrrolidone-b- N, N-diethylacrylamide).

Science.gov (United States)

Zhang, Xiayun; Yang, Zhongduo; Xie, Dengmin; Liu, Donglei; Chen, Zhenbin; Li, Ke; Li, Zhizhong; Tichnell, Brandon; Liu, Zhen

2018-01-01

The reversible addition fragmentation chain transfer (RAFT) polymerization method was adopted here to prepare a series of thermo-sensitive copolymers, poly (N,N-diethyl- acrylamide-b-N-vinylpyrrolidone). Their structures, molecular weight distribution and temperature sensitivity performances were characterized by the nuclear magnetic resonance ( 1 HNMR), the gel permeation chromatography (GPC) and the fluorescence spectrophotometer, respectively. It has been identified that the synthesis reaction of the block copolymer was living polymerization. The thermo-sensitivity study suggested that N-vinylpyrrolidone (NVP), played a key role on the lower critical solution temperature (LCST) performance.

VRPI Thermoresponsive Reversibly Attachable Patch for Temporary Intervention in Ocular Trauma

Science.gov (United States)

2015-11-01

closure for the eye. The enabling technology is a thermo-reversible adhesive ( poly n-isopropyl acrylamide), PNIPAM, which is adhesive to tissues at body...trauma; sclera; hydrogel; PNIPAM; thermo-responsive polymer; open globe; critical care; combat casualty care; poly -n-isopropyl acrylamide. 3...visible or observable signs of discomfort, pain or distress were observed in the treatment group animals after the placement procedure. The afternoon

Nanoclay filled hydrogels of poly (2-hydroxyethyl methacrylate-co-acrylamide) copolymers prepared by gamma radiation

International Nuclear Information System (INIS)

Rapado Paneque, M.; Matos Cause, W.; Barreras Gonzalez, G.; Griffith Perez, J.; Amalvy, J. I.; Van Espen, P.; Peniche, C.

2011-01-01

Hydrogels are polymers characterized by their ability to absorb a considerable amount of water. Hydrogels consist of polymer molecules physically or chemically crosslinked, forming a molecular network, so that in water they swell to an equilibrium value, preserving their shape [1]. The aim of this work was to prepare by gamma radiation poly (2-hydroxyethyl methacrylate-co-acrylamide) hydrogels, p(HEMA-co-AAm), doped with Nanoclay (laponite XLG). (Author)

Selective adsorption of Pb (II) ions by amylopectin-g-poly (acrylamide-co-acrylic acid): A bio-degradable graft copolymer.

Science.gov (United States)

Sasmal, Dinabandhu; Maity, Jayanta; Kolya, Haradhan; Tripathy, Tridib

2017-04-01

Amylopectin-g-poly (acrylamide-co-acrylic acid) [AP-g-poly (AM-co-AA)] was synthesised in water medium by using potassium perdisulphate as an initiator. The graft copolymer was characterized by molecular weight determination by size exclusion chromatography (SEC), fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscope (SEM) studies, thermal analysis, measurement of neutralisation equivalent and biodegradation studies. The graft copolymer was used for Pb (II) ion removal from aqueous solution. The Pb (II) ion removal capacity of the graft copolymer was also compared with another laboratory developed graft copolymer Amylopectin-g-poly (acrylamide) (AP-g-PAM). Both the graft copolymers were also used for the competitive metal ions removal with Pb (II)/Cd (II), Pb (II)/Zn (II), Pb (II)/Ni (II), Pb (II)/Cu (II) pairs separately under similar conditions. AP-g-poly (AM-co-AA) showed better Pb (II) ion adsorbing power over AP-g-PAM and also much selective towards Pb (II) ions. The adsorption follows a second order rate equation and Langmuir isotherm model. Copyright © 2017 Elsevier B.V. All rights reserved.

Drug delivery system prepared by ionizing radiation of the N,N-dimethyl acrylamide with acryloyloxy-acetanilide copolymerization; Sistema de liberacao de droga obtido via radiacao ionizante pela copolimerizacao do N,N-dimetilacrilamida com 4-acriloiloxiacetanilida

Energy Technology Data Exchange (ETDEWEB)

Martellini, Flavia; Higa, Olga Z. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Queiroz, Alvaro A.A. de [Escola Federal de Engenharia de Itajuba, MG (Brazil); Rodighiero, Paolo [Universidade de Padova (Italy). Inst. de Ciencias Farmaceuticas

1995-12-31

Radiation induced polymerization has been used in biomaterials used in systems which such as drug delivery (DDS). This work describes the copolymerization of the monomers by gamma rays N,N-dimethyl acrylamide (DMAA) and acryloyloxy-acetanilide (AOA) for the immobilization of paracetamol, an analgesic and anti thermic drug. Dimethylformamide solutions were used in two concentrations of DMAA and AOA (F{sub DMAA/AOA} = 0,85/015 and 0,70/0,30, where F = molar fraction in the monomer feed). The samples were irradiated in the dose range of 30-800 Gy. The copolymer poly(DMAA-co-AOA) characterization was carried out by FTIR and {sup 1}HRMN. The hydrolysis was studied considering the formation of sodium salts of 4-hydroxy acetanilide at different times of treatment using colorimetric assay. (author). 6 refs., 5 figs.

Synthesis and characterization of cds-p (nipam-co-maa) hybrid micro gels

International Nuclear Information System (INIS)

Khan, M.S.; Khan, G.T.; Khan, A.

2014-01-01

Copolymer containing both pH and thermo sensitive properties are very much interesting due to their broad nature to various stimuli. Further, the incorporation of inorganic nanoparticles into stimuli responsive copolymers enhances their utility in different applied nature properties. In the present work such an attempt is made to synthesize copolymer of N-isopropyl acrylamide (NIPAM) and Methacrylic acid (MAA) with CdS nanoparticles. The copolymer of N-isopropyl acrylamide (NIPAM) and Methacrylic acid (MAA) was prepared through emulsion polymerization technique with various compositions and characterized by Fourier transform infrared spectroscopy (FTIR). The microspheres thus prepared were employed as micro-reactors for the deposition of semiconductor cadmium sulfide (CdS) nanoparticles. The obtained composite was characterized using optical, structural and thermal techniques. The micro gels were found to be stable up to 200 degree C. The crystal structure and grain size of Cadmium sulfide-poly (isopropylacrylamide-co-methacrylic acid) (CdS-P(NIPAM-co-MAA)) hybrid micro gels was studied by using X - ray Diffraction. UV Visible spectroscopy and photoluminescence spectroscopy was engaged to get the optical properties of the samples. It was found that the synthesized nanoparticles have a blue shift (higher energy) at about 360 nm which may be due to the typical quantum confinement effects. (author)

Radiation induced graft copolymerization of acrylamide onto poly (3-hydroxybutyrate)

International Nuclear Information System (INIS)

Gonzalez Torres, Maykel; Rapado Paneque, Manuel; Paredes Zaldivar, Mayte; Altanes Valentin, Sonia; Barrera Gonzalez, Gisela

2008-01-01

The graft copolymer poly (3-hydroxybutyrate)-g- polyacrylamide [P (HB-g-AAm)] was synthesized by radiation induced graft copolymerization of acrylamide onto poly (3-hydroxybutyrate). The study was conducted by the simultaneous irradiation method. The structure of [P (HB-g-AAm)] was identified by Fourier Transform Infrared (FTIR) spectroscopy. Thermal behavior of the graft copolymer was also studied by Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). From the results it was found that FTIR studies showed new signals (stretching -N-H) as strong evidence of grafting. The grafting degree was found to be 10 % and the thermodynamic parameter obtained from the DSC thermogram of plain PHB and the graft copolymer varied showing decrease in the material crystallinity and increase in the glass transition temperature. These results demonstrate that the radiation induced graft copolymerization reaction of acrylamide onto PHB was successively achieved. (Author)

Investigation of Complexation of Linear Poly(N-vinyl-2-pyrrolidone) with Poly(methacrylic acid-co-methyl methacrylate) Gel

OpenAIRE

Liu, Guoqin; Yan, Guojin; Zou, Wenjun; Li, Zhengxin

2011-01-01

The contraction of poly(methacrylic acid-co-methyl methacrylate) (P(MAA-co-MMA)) gel induced by complexation with linear poly(N-vinyl-2-pyrrolidone) (PVP) is quite different from that of poly(acrylic acid) (PAA) or poly(methacrylic acid) (PMAA) gel. It was found that the concentration of PVP has a strong effect on the complexation with P(MAA-co-MMA) gel. When PVP was introduced into the P(MAA-co-MMA) network, its dynamic mechanic properties vary greatly between complexed and uncomplexed netwo...

Synthesis, characterization and application of poly(acrylamide-co-methylenbisacrylamide) nanocomposite as a colorimetric chemosensor for visual detection of trace levels of Hg and Pb ions

Energy Technology Data Exchange (ETDEWEB)

Sedghi, Roya, E-mail: r_sedghi@sbu.ac.ir; Heidari, Bahareh; Behbahani, Mohammad

2015-03-21

Highlights: • Poly(acrylamide-co-methylenbisacrylamide) nanocomposite. • Colorimetric chemosensor. • Determination of trace levels of Hg and Pb ions. • Environmental samples. - Abstract: In this study, a new colorimetric chemosensor based on TiO{sub 2}/poly(acrylamide-co-methylenbisacrylamide) nanocomposites was designed for determination of mercury and lead ions at trace levels in environmental samples. The removal and preconcentration of lead and mercury ions on the sorbent was achieved due to sharing an electron pair of N and O groups of polymer chains with the mentioned heavy metal ions. The hydrogel sensor was designed by surface modification of a synthesized TiO{sub 2} nanoparticles using methacryloxypropyltrimethoxysilan (MAPTMS), which provided a reactive C=C bond that polymerized the acrylamide and methylenbisacrylamide. The sorbent was characterized using X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), EDS analysis and Fourier transform in frared (FT-IR) spectrometer. This nanostructured composite with polymer shell was developed as a sensitive and selective sorbent for adsorption of mercury and lead ions from aqueous solution at optimized condition. This method involves two-steps: (1) preconcentration of mercury and lead ions by the synthesized sorbent and (2) its selective monitoring of the target ions by complexation with dithizone (DZ). The color of the sorbent in the absence and presence of mercury and lead ions shifts from white to violet and red, respectively. The detection limit of the synthesized nanochemosensor for mercury and lead ions was 1 and 10 μg L{sup −1}, respectively. The method was successfully applied for trace detection of mercury and lead ions in tap, river, and sea water samples.

Investigation of Complexation of Linear Poly(N-vinyl-2-pyrrolidone with Poly(methacrylic acid-co-methyl methacrylate Gel

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Guoqin Liu

2011-01-01

Full Text Available The contraction of poly(methacrylic acid-co-methyl methacrylate (P(MAA-co-MMA gel induced by complexation with linear poly(N-vinyl-2-pyrrolidone (PVP is quite different from that of poly(acrylic acid (PAA or poly(methacrylic acid (PMAA gel. It was found that the concentration of PVP has a strong effect on the complexation with P(MAA-co-MMA gel. When PVP was introduced into the P(MAA-co-MMA network, its dynamic mechanic properties vary greatly between complexed and uncomplexed networks. It had the following results: (1 the higher modulus ratio; (2 a slight contraction of gel.

Dependence of crystallinity degree with induced grafting by gamma radiation of N,N'-dimethyl acrylamide

International Nuclear Information System (INIS)

Queiroz, A.A.A.; Higa, O.Z.; Barrak, E.R.; Giolito, I.

1991-01-01

N,N' -dimethyl acrylamide (DMAA) graft copolymerization onto polyethylene films was carried out, using a organic solvent as a reaction medium and gamma rays from a 60 Co source for surface activation. Thermal analysis revealed the crystallinity and the grafting inversely proportional. The DSC curves fusion peaks decreased with grafting rate increase, the peak almost disappearing in the curve of PE 440% grafted. It was concluded that the graft occurs not only on the surface but also in the substrate bulk, being the PE absorption of DMAA an important factor for build up of grafted mass. (author)

Mechanical properties of poly(N-isopropylacrylamide-Co-itaconic acid) hydrogels

International Nuclear Information System (INIS)

Valderruten, N. E.; Quintana, J. R.; Katime, I.

2001-01-01

It is well known that polymers of N-isopropylacrylamide (NIPA) show lower critical solution temperature (LCST) behavior in water and its gels have a volume phase transition at about 34 degree centigree in water. In this study, we reported the polymerization of NIPA in the presence of N,N methylenebisacrylamide (BIS). Poly(N-isopropylacrylamide) and poly(N-isopropylacrylamide-co-itaconic acid) hydrogels were obtained by swelling the resultant solid xerogels to equilibrium in water. The effects of monomer composition and concentration of added cross-linking agent on the swelling behavior and mechanical properties of these hydrogels at 22 and 37 degree centigree were investigated, the latter involving measurements of shear in a DMTA system. The storage moduli at 22 degree centigree lay within the range 9.08-5.08 KPa. At a fixed BIS concentration, an increase from 22 to 37 degree centigree resulted in an increase in the shear moduli and the effective crosslinking density (v e ) and a decrease in the interaction parameter hydrogel/water, χ. (Author) 6 refs

Swelling properties of cassava starch grafted with poly (potassium acrylate-co-acrylamide) superabsorbent hydrogel prepared by ionizing radiation

Science.gov (United States)

Barleany, Dhena Ria; Ulfiyani, Fida; Istiqomah, Shafina; Heriyanto, Heri; Rahmayetty, Erizal

2015-12-01

Natural and synthetic hydrophylic polymers can be phisically or chemically cross-linked in order to produce hydrogels. Starch based hydrogels grafted with copolymers from acrylic acid or acrylamide have become very popular for water absorbent application. Superabsorbent hydrogels made from Cassava starch grafted with poly (potassium acrylate-co-acrylamide) were prepared by using of ϒ-irradiation method. Various important parameters such as irradiation doses, monomer to Cassava starch ratio and acrylamide content were investigated. The addition of 7,5 % w w-1 acrylamide into the reaction mixture generated a starch graft copolymer with a water absorption in distilled water as high as 460 g g-1 of its dried weight. The effectivity of hydrogel as superabsorbent for aqueous solutions of NaCl and urea was evaluated. The obtained hydrogel showed the maximum absorptions of 317 g g-1 and 523 g g-1 for NaCl and urea solution, respectively (relative to its own dry weight). The structure of the graft copolymer was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM).

Swellable molecularly imprinted polyN-(N-propyl)acrylamide particles for detection of emerging organic contaminants using surface plasmon resonance spectroscopy.

Science.gov (United States)

Lavine, Barry K; Westover, David J; Kaval, Necati; Mirjankar, Nikhil; Oxenford, Leah; Mwangi, George K

2007-05-15

Lightly crosslinked theophylline imprinted polyN-(N-propyl)acrylamide particles (ca. 300nm in diameter) that are designed to swell and shrink as a function of analyte concentration in aqueous media were spin coated onto a gold surface. The nanospheres responded selectively to the targeted analyte due to molecular imprinting. Chemical sensing was based on changes in the refractive index of the imprinted particles that accompanied swelling due to binding of the targeted analyte, which was detected using surface plasmon resonance (SPR) spectroscopy. Because swelling leads to an increase in the percentage of water in the polymer, the refractive index of the polymer nanospheres decreased as the particles swelled. In the presence of aqueous theophylline at concentrations as low as 10(-6)M, particle swelling is both pronounced and readily detectable. The full scale response of the imprinted particles to template occurs in less than 10min. Swelling is also reversible and independent of the ionic strength of the solution in contact with the polymer. Replicate precision is less than 10(-4) RI units. By comparison, there is no response to caffeine which is similar in structure to theophylline at concentrations as high as 1x10(-2)M. Changes in the refractive index of the imprinted polymer particles, as low as 10(-4) RI units could be readily detected. A unique aspect of the prepared particles is the use of light crosslinking rather than heavy crosslinking. This is a significant development as it indicates that heavy crosslinking is not entirely necessary for selectivity in molecular imprinting with polyacrylamides.

Studies on chemically crosslinkable carboxy terminated-poly(propylene fumarate-co-ethylene glycol)-acrylamide hydrogel as an injectable biomaterial

International Nuclear Information System (INIS)

Kallukalam, B C; Jayabalan, M; Sankar, V

2009-01-01

Carboxy terminated-poly(propylene fumarate)-co-ethylene glycol) (CT-PPF-co-PEG) was prepared and set into crosslinked hydrogel material with acrylamide. The setting studies reveal that this copolymer system can be used as an injectable material. The hydrogel material exhibits a higher degree of swelling, good mechanical strength and flexibility. The hydrogel favours adhesion of L929 fibroblast cells without proliferation on the surface. However, cardiac fibroblast cells (isolated from new born rat (Wistar) hearts) adhere and proliferate on the hydrogel due to the formation of synergistic hydrophilic-hydrophobic surface-by-surface reorganization.

Studies on chemically crosslinkable carboxy terminated-poly(propylene fumarate-co-ethylene glycol)-acrylamide hydrogel as an injectable biomaterial

Energy Technology Data Exchange (ETDEWEB)

Kallukalam, B C; Jayabalan, M [Polymer Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695 012 (India); Sankar, V, E-mail: muthujayabalan@rediffmail.co [Division of Cellular and Molecular Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695 012 (India)

2009-02-15

Carboxy terminated-poly(propylene fumarate)-co-ethylene glycol) (CT-PPF-co-PEG) was prepared and set into crosslinked hydrogel material with acrylamide. The setting studies reveal that this copolymer system can be used as an injectable material. The hydrogel material exhibits a higher degree of swelling, good mechanical strength and flexibility. The hydrogel favours adhesion of L929 fibroblast cells without proliferation on the surface. However, cardiac fibroblast cells (isolated from new born rat (Wistar) hearts) adhere and proliferate on the hydrogel due to the formation of synergistic hydrophilic-hydrophobic surface-by-surface reorganization.

Swelling properties of cassava starch grafted with poly (potassium acrylate-co-acrylamide) superabsorbent hydrogel prepared by ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

Barleany, Dhena Ria, E-mail: dbarleany@yahoo.com; Ulfiyani, Fida; Istiqomah, Shafina; Rahmayetty [Department of Chemical Engineering, University of Sultan Ageng Tirtayasa, Cilegon, Banten (Indonesia); Heriyanto, Heri; Erizal [Centre for Application of Isotopes and Radiation, Jakarta (Indonesia)

2015-12-29

Natural and synthetic hydrophylic polymers can be phisically or chemically cross-linked in order to produce hydrogels. Starch based hydrogels grafted with copolymers from acrylic acid or acrylamide have become very popular for water absorbent application. Superabsorbent hydrogels made from Cassava starch grafted with poly (potassium acrylate-co-acrylamide) were prepared by using of ϒ-irradiation method. Various important parameters such as irradiation doses, monomer to Cassava starch ratio and acrylamide content were investigated. The addition of 7,5 % w w{sup −1} acrylamide into the reaction mixture generated a starch graft copolymer with a water absorption in distilled water as high as 460 g g{sup −1} of its dried weight. The effectivity of hydrogel as superabsorbent for aqueous solutions of NaCl and urea was evaluated. The obtained hydrogel showed the maximum absorptions of 317 g g{sup −1} and 523 g g{sup −1} for NaCl and urea solution, respectively (relative to its own dry weight). The structure of the graft copolymer was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM)

Adsorção de poli(acrilamida-b-N,N-dihexilacrilamida sobre arenito: determinação das condições para se atingir o equilíbrio real Poly(acrylamide-b-N,N-dihexylacrylamide adsorption on sandstone: determination of the conditions to reach the real equilibrium

Directory of Open Access Journals (Sweden)

Ana Maria S. Maia

2007-03-01

Full Text Available Durante as últimas décadas, o interesse em polímeros anfifílicos tem aumentado continuamente. Neste trabalho, o comportamento do copolímero hidrofílico/hidrofóbico poli(acrilamida-b-N,N-dihexilacrilamida (PADHA na interface sólido/líquido foi estudado para se quantificar a adsorção quando o equilíbrio do sistema é atingido. Na interface água/arenito, a isoterma de adsorção para a PADHA mostrou uma forma incomum, caracterizada pela ausência de uma região de patamar e um aumento contínuo na quantidade adsorvida com a concentração polimérica. Esta forma de adsorção particular poderia ser explicada pela formação de múltiplas camadas devido a associações hidrofóbicas, através das quais as camadas adsorvidas seriam formadas, em parte, por algumas cadeias que não estão diretamente em contato com a superfície sólida.During the last few decades, interest in amphiphilic polymers has increased steadily. In this work, the behavior of the hydrophilic/hydrophobic copolymer poly(acrylamide-b-N,N-dihexylacrylamide (PADHA at a solid/liquid interface has been studied to quantify adsorption at equilibrium. At the water/sandstone interface, the adsorption isotherm for PADHA show an unusual profile, characterized by the absence of a "plateau" region and a monotonic increase in the adsorbed amount with polymer concentration in the bulk. This particular adsorption profile could be explained by the formation of multiple layers caused by hydrophobic associations, the adsorbed layers being partly formed by chains that are not directly in contact with the surface.

The Synthesis of Backbone Thermo and pH Responsive Hyperbranched Poly(Bis(N,N-Propyl Acryl Amides by RAFT

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Shijiao Zhou

2016-04-01

Full Text Available Hyperbranched poly(methylene-bis-acrylamide, poly(bis(N,N-propyl acryl amide (HPNPAM and poly(bis(N,N-butyl acryl amide were synthesized by reversible addition-fragmentation chain transfer polymerization. HPNPAMs showed lower critical solution temperature (LCST due to an appropriate ratio between hydrophilic and hydrophobic groups. The effects of reaction conditions on polymerization were investigated in detail. The structure of HPNPAM was characterized by 1H NMR, FT-IR, Muti detector-size exclusion chromatography (MDSEC and Ultravioletvisble (UV-Vis. The α value reached 0.20 and DB was 90%, indicating HPNPAMs with compact topology structure were successfully prepared. LCSTs were tuned by Mw and the pH value of the solution. The change of molecular size was assayed by dynamic light scattering and scanning electron microscope. These results indicated that the stable uniform nanomicelles were destroyed and macromolecules aggregated together, forming large particles as temperature exceeded LCST. In addition, after the cells were incubated for 24 h, the cell viability reached 80%, which confirmed this new dual responsive HPNPAM had low cytotoxicity.

A facile metal-free "grafting-from" route from acrylamide-based substrate toward complex macromolecular combs

KAUST Repository

Zhao, Junpeng

2013-01-01

High-molecular-weight poly(N,N-dimethylacrylamide-co-acrylamide) was used as a model functional substrate to investigate phosphazene base (t-BuP 4)-promoted metal-free anionic graft polymerization utilizing primary amide moieties as initiating sites. The (co)polymerization of epoxides was proven to be effective, leading to macromolecular combs with side chains being single- or double-graft homopolymer, block copolymer and statistical copolymer. © 2013 The Royal Society of Chemistry.

Thermo-sensitive and swelling properties of cellouronic acid sodium/poly (acrylamide-co-diallyldimethylammonium chloride) semi-IPN.

Science.gov (United States)

Zhang, Heng; Gao, Xin; Chen, Keli; Li, Hui; Peng, Lincai

2018-02-01

In current study, cellouronic acid sodium (CAS), obtained from bagasse pith, has been introduced into poly(acrylamide-co-diallyldimethylammonium chloride) (poly(AM-co-DAC)) network to form novel thermo-sensitive semi-IPNs. The structure and morphology of the hydrogels were proved by Fourier transformation infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The effects of CAS content, initiator charge, cross-linker dosage and swelling-medium property on the thermo-responsive water absorptivity were investigated in detail. The results elucidated that the prepared gels exhibited a thermo-sensibility with an upper critical solution temperature (UCST) and a high water-absorbency. And the values of UCST and equilibrium swelling ratio largely depended on the inner structure of the semi-IPNs and the external solvent property. It was also revealed that the swelling process conformed to the Schott's pseudo second order model and diffusion type was non-Fickian diffusion. The value of activation energy for this polyelectrolyte was found to be 8.74kJ/mol. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enhanced protein retention on poly(caprolactone) via surface initiated polymerization of acrylamide

International Nuclear Information System (INIS)

Ma, Yuhao; Cai, Mengtan; He, Liu; Luo, Xianglin

2016-01-01

Graphical abstract: - Highlights: • Dense package of poly(acrylamide) on poly(caprolactone) surface was achieved by surface-initiated atom transfer radical polymerization. • Poly(acrylamide) grafted surface exhibited high protein retention ability. • Loaded protein was resistant to detachment and maintained its structure without denaturation. - Abstract: To enhance the biocompatibility or extend the biomedical application of poly(caprolactone) (PCL), protein retention on PCL surface is often required. In this study, poly(acrylamide) (PAAm) brushes were grown from PCL surface via surface-initiated atom transfer radical polymerization (SI-ATRP) and served as a protein-capturing platform. Grafted PAAm was densely packed on surface and exhibited superior protein retention ability. Captured protein was found to be resistant to washing under detergent environment. Furthermore, protein structure after being captured was investigated by circular dichroism (CD) spectroscopy, and the CD spectra verified that secondary structure of captured proteins was maintained, indicating no denaturation of protein happened for retention process.

PREPARATION AND CATALYTIC ACTIVITY FOR ISOPROPYL BENZENE CRACKING OF Co, Mo AND Co/Mo-Al2O3-PILLARED MONTMORILLONITE CATALYSTS

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Hasanudin Hasanudin

2010-06-01

Full Text Available It has been prepared Co, Mo and Co/Mo-Al2O3-pillared montmorillonite catalysts using montmorillonite clay  as raw material. The structure and porosity of the catalysts were determined using N2 adsorption-desorption and FT-IR spectroscopy analysis methods. Isopropyl benzene cracking using these catalysts were used to test the catalytic activity and performance of Co, Mo and Co/Mo-Al2O3-pillared montmorillonites.  Characterization results showed that pillarization resulted in the increase of the total pore volume and specific surface area of the clay. Meanwhile, transition metals (Co, Mo and Co/Mo loaded on Al2O3-pillared monmorillonites could increase the catalytic activity of the catalysts for isopropyl benzene cracking significantly.   Keywords: pillared monmorillonite, isopropyl benzene  and cracking catalyst

Preparation and Investigation of Poly (N-isopropylacrylamide-acrylamide Membranes in Temperature Responsive Drug Delivery

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Elham Khodaverdi

2010-06-01

Full Text Available Objective(sPhysiological changes in the body may be utilized as potential triggers for controlled drug delivery. Based on these mechanisms, stimulus–responsive drug delivery has been developed.Materials and MethodsIn this study, a kind of poly (N-isopropylacrylamide-acrylamide membrane was prepared by radical copolymerization. Changes in swelling ratios and diameters of the membrane were investigated in terms of temperature. On-off regulation of drug permeation through the membrane was then studied at temperatures below and above the phase transition temperature of the membrane. Two drugs, vitamin B12 and acetaminophen were chosen as models of high and low molecular weights here, respectively. ResultsIt was indicated that at temperatures below the phase transition temperature of the membrane, copolymer was in a swollen state. Above the phase transition temperature, water was partially expelled from the functional groups of the copolymer. Permeation of high molecular weight drug models such as vitamin B12 was shown to be much more distinct at temperatures below the phase transition temperature when the copolymer was in a swollen state. At higher temperatures when the copolymer was shrunken, drug permeation through the membrane was substantially decreased. However for acetaminophen, such a big change in drug permeation around the phase transition temperature of the membrane was not observed. ConclusionAccording to the pore mechanism of drug transport through hydrogels, permeability of solutes decreased with increasing molecular size. As a result, the relative permeability, around the phase transition temperature of the copolymer, was higher for solutes of high molecular weight.

Temperature and Recognition Dual Responsive Poly(N-Isopropylacrylamide) and Poly(N,N-Dimethylacrylamide) with Adamantyl Side Group.

Science.gov (United States)

Dong, Qiujing; Luo, Chunhua; Li, Na; Chi, Jiaxiang; Zhang, Qingqing

2018-03-22

A series of copolymers with an adamantyl side group (poly(NIPAM-co-AdMA) and poly(DMAM-co-AdMA)) were prepared by radical copolymerization of N -isopropylacrylamide (NIPAM) and N , N -dimethylacrylamide (DMAM) with a 2-methyl-2-adamantylmethacrylate (AdMA) monomer. The structure and composition of the as-synthesized copolymers were characterized by Fourier transform infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (¹H NMR) spectroscopy, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), and elemental analysis. Temperature and recognition dual responsivity of the copolymers was investigated by cloud point (T cp ) and dynamic light scattering (DLS), respectively. The results show that the as-synthesized copolymers are a kind of temperature-responsive polymer with a lower critical solution temperature (LCST). T cp was approximately consistent with the critical temperature of intermolecular copolymer association (T ass ) from DLS. For these copolymers, T cp decreases with increasing content of AdMA unit in the copolymers. After the addition of β-cyclodextrins (β-CD), T cp increases, and the increment of T cp values gradually became large with increasing content of AdMA in the copolymers. It is host-guest molecular recognition of β-CD and adamantyl groups that endows the as-synthesized copolymers with recognition-tunable thermosensitivity.

NOVEL SUPERABSORBENT HYDROGEL COMPOSITE BASED ON POLY(ACRYLAMIDE-CO-ACRYLATE/NONTRONITE: CHARACTERIZATION AND SWELLING PERFORMANCE

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Renan C. F. Leitão

2015-03-01

Full Text Available A novel superabsorbent hydrogel (SH composite based on a poly(acrylamide-co-acrylate matrix filled with nontronite (NONT, a Fe(III-rich member of the smectite group of clay minerals, is described in this manuscript. A variety of techniques, including FTIR, XRD, TGA, and SEM/EDX, were utilized to characterize this original composite. Experimental data confirmed the SH composite formation and suggested NONT was completely dispersed in the polymeric matrix. Additionally, NONT improved the water uptake capacity of the final material, which exhibited fast absorption, low sensitivity to the presence of salt, high water retention and a pH sensitive properties. These preliminary data showed that the original SH composite prepared here possesses highly attractive properties for applications in areas such as the agriculture field, particularly as a soil conditioner.

Investigation of nanocomposites made with poly(methacrylic acid-co-methyl methacrylate/poly(N-vinyl-2-pyrrolidone/multi-walled carbon nanotubes

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Liu Guoqin

2014-01-01

Full Text Available Poly(methacrylic acid-co-methyl methacrylate (P(MAA-co-MMA was prepared in the presence of poly(N-vinyl-2-pyrrolidone (PVP and multiwalled carbon nanotubes (MWNTs via ultrasonic assisted solution free radical polymerization, i.e., P(MAA-co-MMA/PVP/MWNTs nanocomposites. The morphology, glassy-state storage modulus, thermal behavior and swelling characteristics of P(MAA-co-MMA/PVP/MWNTs nanocomposites were investigated. Scanning electron micrographs (SEM revealed that MWNTs at low concentration could be uniformly dispersed into P(MAA-co-MMA/PVP blends. With increasing MWNTs weight fraction, the average glassy-state modulus, glass transition temperatures and decomposition temperature of the nanocomposites increased, but their swelling characteristics decreased.

Investigation of nanocomposites made with poly(methacrylic acid-co-methyl methacrylate)/poly(N-vinyl-2-pyrrolidone)/multi-walled carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Guoqin, Liu; Wei, Miao [College of Material Science and Engineering, Henan University of Technology (China); Lin-Jian, Shangguan, E-mail: mikepolymer@126.com [School of Mechanical Engineering, North China University of Water Conservancy and Electric Power (China)

2014-06-01

Poly(methacrylic acid-co-methyl methacrylate) (P(MAA-co-MMA)) was prepared in the presence of poly(N-vinyl-2-pyrrolidone) (PVP) and multi-walled carbon nanotubes (MWNTs) via ultrasonic assisted solution free radical polymerization, i.e., P(MAA-co-MMA)/PVP/MWNTs nanocomposites. The morphology, glassy-state storage modulus, thermal behavior and swelling characteristics of P(MAA-co-MMA)/PVP/MWNTs nanocomposites were investigated. Scanning electron micrographs (SEM) revealed that MWNTs at low concentration could be uniformly dispersed into P(MAA-co-MMA)/PVP blends. With increasing MWNTs weight fraction, the average glassy-state modulus, glass transition temperatures and decomposition temperature of the nanocomposites increased, but their swelling characteristics decreased. (author)

Thermoresponsive polymers as promising new materials for local radiotherapy

Czech Academy of Sciences Publication Activity Database

Hrubý, Martin; Šubr, Vladimír; Kučka, J.; Kozempel, J.; Lebeda, Ondřej; Sikora, Antonín

2005-01-01

Roč. 63, č. 4 (2005), s. 423-431 ISSN 0969-8043 R&D Projects: GA AV ČR KJB4050408 Keywords : thermoresponsive * polymer * poly(N-isopropyl acrylamide) Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.757, year: 2005

Brain perfusion image using N-isopropyl-p-[123I] iodoamphetamine

International Nuclear Information System (INIS)

Matsuda, Hiroshi; Seki, Hiroyasu; Ishida, Hiroko

1984-01-01

In brain perfusion images using N-Isopropyl-p-[ 123 I] Iodoamphetamine and rotating gamma camera emission computed tomography, brain maps showing laterality indices (LI) were made for the purpose of detecting ineterhemispheric differences. Left (L) and right (R) leteral images were made by adding sagittal section images in each hemisphere, respectively. LI was calculated as follows. LI=100(1+(R-L)/(R+L)). The normal ranges (mean+-2 s.d.) of the indices determined by those obtained in five normal right-handed subjects were 103+-4 and 103+-10 for brain mean and each pixel, respectively. Out of 25 measurements in 22 righthanded patients with cerebrovascular accidents, brain mean LI beyond the normal limits and areas showing abnormal regional LI were observed in 5 (20%) and 21 (84%) measurements, respectively. On the other hand, X-ray CT showed low density areas in only 12 (48%). These brain maps were clinically useful for detecting and quantifying interhemispheric differences in brain perfusion images with N-Isopropyl-p-[ 123 I] Iodoamphetamine. (author)

Propiedades mecánicas de hidrogeles de poli(N-sopropilacrilamida-Co-ácido itacónico

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Valdeturren, N. E.

2001-04-01

Full Text Available It is well known that polymers of N-isopropylacrylamide (NIPA show lower critical solution temperature (LCST behavior in water and its gels have a volume phase transition at about 34 °C in water. In this study, we reported the polimerization of NIPA in the presence of N,N'-methylenebisacrylamide (BIS. Poly(N-isopropylacrylamide and poly(N-isopropylacrylamide-co-itaconic acid hydrogels were obtained by swelling the resultant solid xerogels to equilibrium in water. The effects of monomer composition and concentration of added cross-linking agent on the swelling behavior and mechanical properties of these hydrogels at 22 and 37 °C were investigated, the latter involving measurements of shear in a DMTA system. The storage moduli at 22 °C lay within the range 9.08-5.08 KPa. At a fixed BIS concentration, an increase from 22 to 37 °C resulted in an increase in the shear moduli and the effective crosslinking density (ν_e and a decrease in the interaction parameter hydrogel/water, χ.

Los hidrogeles de N-isopropilacrilamida (NIPA son matrices orgánicas termosensibles que sufren una transición de fase en volumen en agua a su temperatura crítica consoluta inferior (LCST, que está alrededor de 34 °C. En este trabajo presentamos la polimerización de NIPA utilizando como entrecruzante N,N'-metilenbisacrilamida (BIS . Los hidrogeles de poli(N-isopropilacrilamida y poli(N-isopropilacrilamida-co-ácido itacónico se obtuvieron hinchando hasta el equilibrio los xerogeles resultantes. Se evaluaron los efectos de la composición de comonómeros y la concentración de agente entrecruzante sobre el comportamiento de hinchamiento y las propiedades mecánicas de estos hidrogeles a 22 y 37 °C. Las medidas mecánicas se hicieron en un DMTA. El módulo de almacenamiento a 22 °C presentó valores comprendidos entre 9,08 y 5,08 KPa. A una concentración constante de BIS, un incremento en la temperatura de 22 a 37 °C ocasionó un aumento del m

Synthesis of Poly(N-vinyl-2-pyrrolidone-co-methyl methacrylate by Maghnite-H+ a Non-toxic Catalyst

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Mohamed Benadda

2014-10-01

Full Text Available In the present work poly (N-vinyl-2-pyrrolidone-co-methyl methacrylate copolymers were prepared successfully and cleanly by a one step process via cationic copolymerization of N-vinyl-2-pyrrolidone (NVP with methyl methacrylate (MMA, in heterogeneous phase using “Maghnite-H+” (Mag-H+ as catalyst in bulk, Maghnite is a montmorillonite sheet silicate clay exchanged with protons to produce Maghnite-H+. Temperature is varied between 20 and 80 °C. The effects of reaction temperature, amount of Mag-H+ on the yield and the intrinsic viscosity (η were investigated. A typical reaction product of poly (NVP-co- MMA was analyzed by infra red spectroscopy (FTIR and 1H-NMR, 13C-NMR spectroscopy as well as by viscosimetry. © 2014 BCREC UNDIP. All rights reservedReceived: 24th November 2013; Revised: 30th June 2014; Accepted: 8th July 2014How to Cite: Benadda, M., Ferrahi, M.I., Belbachir, M. (2014. Synthesis of Poly(N-vinyl-2-pyrrolidone-co-methyl methacrylate by Maghnite-H+ a Non-toxic Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (3: 201-206. (doi: 10.9767/bcrec.9.3.5743.201-206Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.3.5743.201-206

New membranes obtained by grafted irradiated PVDF foils

Energy Technology Data Exchange (ETDEWEB)

Mazzei, R. [Unidad de Actividades Tecnologicas y Agropecuarias, Laboratorio de Polimeros, Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Universidad Tecnologica Nacional Facultad Regional, Buenos Aires (Argentina); Garcia Bermudez, G. [Gerencia de Investigacion y Aplicaciones, Laboratorio Tandar, Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Universidad Nacional de General San Martin, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); Camporotondi, D.E., E-mail: camporotondi@cae.cnea.gov.ar [Unidad de Actividades Tecnologicas y Agropecuarias, Laboratorio de Polimeros, Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Arbeitman, C. [Gerencia de Investigacion y Aplicaciones, Laboratorio Tandar, Comision Nacional de Energia Atomica, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires (Argentina); and others

2012-09-15

The present work describes a new method to produce membranes of poly(Acrylic-acid-Xmonomer) using the grafting procedure. PVDF foils irradiated with Ar{sup +} beam with energies between 30 and 150 keV were employed as substratum. Different combinations of monomers in water solutions were used: acrylic acid (AAc); acrylic acid-glycidyl methacrylate (AAc-GMA); acrylic acid-styrene (AAc-S), acrylic acid-N-isopropyl acrylamide (AAc-NIPAAm) and acrylic acid-N-isopropyl acrylamide-glycidyl methacrylate (AAc-NIPAAm-GMA). A large percentage of grafting results for specific values of: ion fluence and energy, AAc and sulfuric acid concentration, and different substrata PVDF polymorphous (alpha or beta). At a particular time of the grafting process, the poly(AAc-Xmonomer) membranes detach from the substratum and continue their grafting in the solution. This method is useful to produce increased replicated membranes of the irradiated original surface.

Thallium-201 diethyldithiocarbamate: an alternative to iodine-123 N-isopropyl-p-iodoamphetamine

NARCIS (Netherlands)

de Bruine, J. F.; van Royen, E. A.; Vyth, A.; de Jong, J. M.; van der Schoot, J. B.

1985-01-01

The study of cerebral blood flow by single photon emission computed tomography (SPECT) requires lipophilic radiopharmaceuticals. The high cost and limited availability of N-isopropyl-p-[I-123]-iodoamphetamine ( [123I]IMP) led us to search for alternatives. Following our recent development of

Gamma radiation-induced preparation of some acrylamide polymers for treatment of waste water

International Nuclear Information System (INIS)

Siyam, T.; Hanna, E.

1992-01-01

Water-soluble acrylamide copolymers such as: poly (acrylamide-co-sodium) [P(AM-CO-AA Na)], (acrylamide-CO-diallylethylamine-hydrochloride) [P(AM-CO-DAEA-H Cl)] and poly (acrylamide-sodium acrylate-diallylethylamine-hydrochloride) [P(AM-AANa-DAEA-H Cl)] were prepared by gamma radiation-initiated polymerization of the corresponding co monomer or termonomer solutions. The prepared copolymers were used in the treatment of water (metal sulphate solutions). It was found that the polymer efficiency increases with increasing the PH-value and the polymer concentration. The efficiency of the different polymers compared in what concerns elimination of Cu++ and Mg++. The polymer dosage depends on the hydration sheath of the cation. The mechanism for interaction of each polymeric chains with the ions of waste water was also discussed. 3 figs, 1 tab

Utilization of wheat straw for the preparation of coated controlled-release fertilizer with the function of water retention.

Science.gov (United States)

Xie, Lihua; Liu, Mingzhu; Ni, Boli; Wang, Yanfang

2012-07-18

With the aim of improving fertilizer use efficiency and minimizing the negative impact on the environment, a new coated controlled-release fertilizer with the function of water retention was prepared. A novel low water solubility macromolecular fertilizer, poly(dimethylourea phosphate) (PDUP), was "designed" and formulated from N,N'-dimethylolurea (DMU) and potassium dihydrogen phosphate. Simultaneously, an eco-friendly superabsorbent composite based on wheat straw (WS), acrylic acid (AA), 2-acryloylamino-2-methyl-1-propanesulfonic acid (AMPS), and N-hydroxymethyl acrylamide (NHMAAm) was synthesized and used as the coating to control the release of nutrient. The nitrogen release profile and water retention capacity of the product were also investigated. The degradation of the coating material in soil solution was studied. Meanwhile, the impact of the content of N-hydroxymethyl acrylamide on the degradation extent was examined. The experimental data showed that the product with good water retention and controlled-release capacities, being economical and eco-friendly, could be promising for applications in agriculture and horticulture.

Synthesis and characterization of super absorbent poly (acrylamide-co-potassium acrylate) hydrogels by radiation technique

International Nuclear Information System (INIS)

Erizal

2010-01-01

A series of super absorbent hydrogels were prepared from acrylamide (AAm) and potassium acrylate (KA) by gamma irradiation technique at room temperature. The solution containing potassium acrylate 15% and different concentrations of AAm (10-16%) were irradiated by gamma rays (20-40 kGy). The hydrogels produced by irradiation were characterized by fourier transform infra red spectroscopy (FT-IR). The gel fraction, kinetics of swelling and the equilibrium degree of swelling (EDS) were studied. Under irradiation dose of 20 kGy and concentration of AAM 10 %), poly(AAm-co-KA) hydrogel with high gel fraction (99.08%) and very high EDS (420 g/g) were obtained. The capacity of hydrogel to adsorb metal ion Cu 2+ and Fe 3+ were investigated. It is shown than 10 minutes the hydrogel could adsorb Cu 2+ ion up to 95 %, and Fe 3+ ion up to 55 % in 80 minutes. This hydrogel has a potential to be used for soil conditioning and ion metal absorbent. (author)

A novel poly(acrylic acid-co-acrylamide)/diatomite composite flocculant with outstanding flocculation performance.

Science.gov (United States)

Xu, Kun; Liu, Yao; Wang, Yang; Tan, Ying; Liang, Xuecheng; Lu, Cuige; Wang, Haiwei; Liu, Xiusheng; Wang, Pixin

2015-01-01

Series of anionic flocculants with outstanding flocculation performance, poly(acrylic acid-co-acrylamide)/diatomite composite flocculants (PAAD) were successfully prepared through aqueous solution copolymerization and applied to flocculate from oil-field fracturing waste-water. The structure of PAAD was characterized by Fourier transform infra-red spectroscopy, (13)C nuclear magnetic resonance and X-ray diffraction tests, and its properties were systematically evaluated by viscometer, thermogravimetry analysis and flocculation measurements. Furthermore, the influences of various reaction parameters on the apparent viscosity of flocculant solution were studied, and the optimum synthesis condition was determined. The novel composite flocculants exhibited outstanding flocculation properties. Specifically, the dosage of composite flocculants that could make the transmittance of treated wastewater exceed 90% was only approximately 12-35 ppm, which was far lower than that of conventional flocculants. Meanwhile, the settling time was lower than 5 s, which was similar to that of conventional flocculants. This was because PAAD flocculants had a higher absorption capacity, and larger chain extending space than conventional linear flocculants, which could refrain from the entanglement of linear polymer chains and significantly improve flocculation capacity.

A convenient method for 14C-labeling of 2-methylthio-1-[4-N-α-ethoxycarbonylbenzyl)-amino-benzyl] -5-hydroxymethyl-2-[14C]-1H-imidazole and 1-[4-N-α-ethoxy-carbonylbenzyl)-aminobenzyl]-5-hydroxymethyl-2-[14C] -1H-imidazole as potential antihypertensives

International Nuclear Information System (INIS)

Nader Saemian; Gholamhossein Shirvani; Mohsen Javaheri; Sayed Sajad Oliyaee

2012-01-01

The key synthetic intermediate, (2-mercapto-1-(4-nitrobenzyl)-1H-imidazol-5-yl)methanol-[2- 14 C], has been synthesized by using one pot procedure from potassium[ 14 C]-thiocyanate. It was converted to two nonpeptide angiotensin II receptor antagonists, 2-methylthio-1-[4-N-α-ethoxycarbonyl benzyl)-aminobenzyl]-5-hydroxymethyl-1H-imidazole-[2- 14 C] and 1-[4-N-α-ethoxy-carbonylbenzyl)-aminobenzyl] -5-hydroxymethyl-1H-imidazole-[2- 14 C] via a 3-step sequence synthetic pathway. (author)

Magnetic hollow poly(N-isopropylacrylamide-co-N,N'-methylenebisacrylamide-co-glycidyl acrylate) particles prepared by inverse emulsion polymerization

Czech Academy of Sciences Publication Activity Database

Macková, Hana; Horák, Daniel; Petrovský, Eduard; Kovářová, Jana

2013-01-01

Roč. 291, č. 1 (2013), s. 205-213 ISSN 0303-402X R&D Projects: GA ČR GAP503/10/0664; GA AV ČR(CZ) KAN401220801 EU Projects: European Commission(XE) 259796 - DIATOOLS Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z30120515 Keywords : magnetic * poly(N-isopropylacrylamide) * particles Subject RIV: EE - Microbiology, Virology Impact factor: 2.410, year: 2013

Novel 3D porous semi-IPN hydrogel scaffolds of silk sericin and poly(N-hydroxyethyl acrylamide for dermal reconstruction

Directory of Open Access Journals (Sweden)

S. Ross

2017-09-01

Full Text Available In this work, a novel semi-interpenetrating polymer network (semi-IPN hydrogel scaffold based on silk sericin (SS and poly(N-hydroxyethyl acrylamide (PHEA was successfully fabricated via conventional free-radical polymerization. The porous structure of the scaffolds was introduced using a lyophilization technique and the effect of cross-linker (XL on morphology, gelation time and physical properties of hydrogel scaffold was first studied. The results show that using low cross-linker content (0.125, 0.25 and 0.5 wt% XL produced flexible scaffolds and appropriate gelation times for fabricating the scaffold. Therefore, the polymerization system with a constant percentage of XL at 0.5 wt% was chosen to study further the effect of SS on the physical properties and cell culture of the scaffolds. It was observed that the hydrogel scaffold of PHEA without SS (PHEA/SS-0 had no cell proliferation, whereas hydrogel scaffolds with SS enhanced cell viability when compared to the positive control. The sample of PHEA/SS at 1.25 wt% of SS and 0.5 wt% of cross-linker was the most suitable for HFF-1 cells to migrate and cell proliferation due to possessing a connective porous structure, along with silk sericin. The results proved that this novel porous semi-IPN hydrogel has the potential to be used as dermal reconstruction scaffold.

Metabolic lung scanning with N-isopropyl-I-123-p-iodoamphetamine

International Nuclear Information System (INIS)

Touya, J.; Akber, S.F.; Rashimian, J.; Bennett, L.R.

1982-01-01

The mechanisms of uptake of N-Isopropyl-I-123-p-Iodoamphetamine (IMP) in the lung was studied in dogs. It has been concluded that this amine is taken in low specificity - high capacity endothelial receptors. Competitive effect of propranolol guanethidine, amphetamine and ketanine for the binding sites of IMP in the pulmonary endothelial cells was observed. These results show that IMP can be an agent for nonparticulate lung perfusion scans as well as for metabolic lung scans

Synthesis of a pH- and Thermo- Responsive Binary Copolymer Poly(N-vinylimidazole-co-N-vinylcaprolactam Grafted onto Silicone Films

Directory of Open Access Journals (Sweden)

Ángela Obando-Mora

2015-10-01

Full Text Available This work focuses on the effects of gamma-ray irradiation conditions on the stimuli-responsiveness of silicone rubber (SR substrates grafted with N-vinylcaprolactam (NVCL and N-vinylimidazole (NVIM, modified by the simultaneously polymerization and grafting method, which is expected to result in valuable new applications in the near future. The modification of silicone rubber was carried out via γ-ray radiation in order to graft a binary copolymer, poly(N-vinylimidazole-co-N-vinylcaprolactam, by the pre-irradiation method, to obtain pH- and thermo-responsive materials. The grafting yield was found to be directly proportional to the dose and monomers concentration. The biomaterials were characterized by using Fourier-transform infrared attenuated total reflection (FTIR-ATR, differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, and swelling; and their stimuli behavior was evaluated by lower critical solution temperature (LCST and pH critical studies.

Synthesis of N-isopropyl p-[123I]iodoamphetamine via organoborane chemistry

International Nuclear Information System (INIS)

Kabalka, G.W.; Varma, R.S.; Gai, Y.

1990-01-01

Iodine-123 labeled amphetamines have proven to be excellent cerebral perfusion tracers. The radioiodination of aromatic amines is generally achieved via high temperature substitution reactions which are prone to side reactions. The authors report that N-isopropyl p-[ 123 I]iodoamphetamine, and other iodophenylamines, are readily synthesized from the corresponding air stable, boronic acids. The reaction is based on the no-carrier-added radioiodination sequence developed in their laboratory

Synthesis, Structures and Properties of Cobalt Thiocyanate Coordination Compounds with 4-(hydroxymethyl)pyridine as Co-ligand

OpenAIRE

Stefan Suckert; Luzia S. Germann; Robert E. Dinnebier; Julia Werner; Christian Näther

2016-01-01

Reaction of Co(NCS)2 with 4-(hydroxymethyl)pyridine (hmpy) leads to the formation of six new coordination compounds with the composition [Co(NCS)2(hmpy))4] (1), [Co(NCS)2(hmpy)4] × H2O (1-H2O), [Co(NCS)2(hmpy)2(EtOH)2] (2), [Co(NCS)2(hmpy)2(H2O)2] (3), [Co(NCS)2(hmpy)2]n∙4 H2O (4) and [Co(NCS)2(hmpy)2]n (5). They were characterized by single crystal and powder X-ray diffraction experiments, thermal and elemental analysis, IR and magnetic measurements. Compound 1 and 1-H2O form discrete comple...

A novel polymer of Al2(SO43-poly(acrylamide-co-2-acrylamido-2-methyl-1-propanesulfonate ionic hybrid prepared by dispersion polymerization

Directory of Open Access Journals (Sweden)

2010-03-01

Full Text Available A novel polymer Al2(SO43-poly(acrylamide-co-2-acrylamido-2-methyl-1-propanesulfonate (Al2(SO43-P(AM/AMPS had been synthesized by dispersion polymerization in an aqueous solution of ammonium sulfate and aluminum sulfate, using poly(2-acrylamido-2-methyl-1-propanesulfonate P(AMPS as stabilizer, acrylamide (AM and 2-acrylamido-2-methyl-1-propanesulfonate (AMPS as monomers, poly(2-acrylamido-2-methyl-1-propanesulfonate (PAMPS as stabilizer and [2-(2-imidazdino-2-ylpropane]dihydrochloride (VA-044 as initiator. The average particle size of polymer dispersion ranged from 0.2 to 0.3 µm, the molecular weight was from 4.3•106 to 5.7•106 g•mol-1. The polymer was characterized by infrared (IR spectroscopy, thermogravimetry (TGA and transmission electron microscopy (TEM. The swelling property of the dispersion polymer was studied by particle size distribution. When the polymer dispersion was diluted with deionized water, particle sizes decreased several times. When the polymer dispersion was diluted with salt water, the particle size increased with increasing concentration of salt. The effects of Al2(SO43 and stabilizer on the particle size and the relative molecular weight of the polymer were investigated, respectively. The optimum conditions for the stable Al2(SO43-P(AM/AMPS dispersion were that the concentration of Al2(SO43 was 1.12 wt%, the concentration of PAMPS stabilizer was 3 wt% and the concentration of initiator was 0.2 mol•l-1 and the monomers concentration was 14 wt%.

Superabsorbent nanocomposite synthesis of cellulose from rice husk grafted poly(acrylate acid-co-acrylamide)/bentonite

Science.gov (United States)

Helmiyati; Abbas, G. H.; Kurniawan, S.

2017-04-01

Superabsorbent nanocomposite synthesis of cellulose rice husk as the backbone with free radical polymerization method in copolymerization grafted with acrylic acid and acrylamide monomer. The cellulose was isolated from rice husk with mixture of toluene and ethanol and then hemicellulose and lignin were removed by using potassium hydroxide 4% and hydrogen peroxide 2%. The obtained cellulose rendement was 37.85%. The functional group of lignin analyzed by FTIR spectra was disappeared at wavenumber 1724 cm-1. Crystal size of the obtained isolated cellulose analyzed by XRD diffraction pattern was 34.6 nm, indicated the nanocrystal structure. Copolymerization was performed at temperature of 70°C with flow nitrogen gas. Initiator and crosslinking agent used were potassium persulfate and N‧N-methylene-bis-acrylamide. The swelling capacity of water and urea showed the results was quite satisfactory, the maximum swelling capacity in urea and water were 611.700 g/g and 451.303 g/g, respectively, and can be applied in agriculture to absorb water and urea fertilizer.

Poly(vinyl-alcohol)/poly(ethylene-glycol)/poly(ethylene-imine) blend membranes - structure and CO2 facilitated transport

International Nuclear Information System (INIS)

Ben Hamouda, S.; Quang, Trong Nguyen; Langevin, D.; Sadok, Roudeslic

2010-01-01

Poly(vinyl-alcohol) (PVA)/poly(ethylene-imine) (PEI)/poly(ethylene-glycol) (PEG) blend membranes were prepared by solution casting followed by solvent evaporation. The effects of the blend polymer composition on the membrane structure and CO 2 /N 2 permeation characteristics were investigated. IR spectroscopy evidenced strong hydrogen bonding interactions between amorphous PVA and PEI, and weaker interactions between PVA and PEG. DSC studies showed that PVA crystallization was partially inhibited by the interactions between amorphous PVA and PEI blend, in which PEG separated into nodules. The CO 2 permeability decreased with an increase in CO 2 partial pressure in feed gas, while the N 2 permeability remained constant. This result indicated that only CO 2 was transported by the facilitated transport mechanism. The CO 2 and N 2 permeabilities increased monotonically with the PEI content in the blend membranes, whereas the ideal selectivity of CO 2 to N 2 transport showed a maximum. When CO 2 is humidified, its permeability through the blend membranes is much higher than that of dry CO 2 , but the change in permeability due to the presence of humidity is reversible. (authors)

Photocrosslinkable Star Polymers via RAFT-Copolymerizations with N-Ethylacrylate-3,4-dimethylmaleimide

Directory of Open Access Journals (Sweden)

Philipp Vana

2013-06-01

Full Text Available This paper describes the Z-RAFT-star copolymerization of n-butyl acrylate (BA and N-isopropyl acrylamide (NIPAm, respectively, with N-ethylacrylate-3,4-dimethylmaleimide (1.1, a monomer carrying a UV-reactive unit that undergoes photocrosslinking. Addition of 1.1 slows down the polymerization rate both for BA and for NIPAm polymerization. Double star formation due to radical attack to the 3,4-dimethylmaleimide moiety was found in the case of BA. Dead polymer formation, presumably due to aminolysis as side-reaction, was pronounced in the NIPAm system. These two effects broadened the molar mass distributions, but did not impede the formation of functional star polymers. The composition of the copolymers as well as the reactivity ratios for the applied comonomers were determined via NMR spectroscopy (BA-co-1.1 r1.1 = 2.24 rBA = 0.95; NIPAm-co-1.1 r1.1 = 0.96 rNIPAm = 0.05. In both cases, the comonomer is consumed preferably in the beginning of the polymerization, thus forming gradient copolymer stars with the UV-reactive units being located in the outer sphere.

Poly(styrene-co-N-methacryloyl-l-phenylalanine methyl ester)-functionalized magnetic nanoparticles as sorbents for the analysis of sodium benzoate in beverages.

Science.gov (United States)

Ji, Shilei; Li, Nan; Qi, Li; Wang, Minglin

2017-01-01

In this study, poly(styrene-co-N-methacryloyl-l-phenylalanine methyl ester)-functionalized magnetic nanoparticles were constructed and used as magnetic solid-phase extraction sorbents for analysis of food preservatives in beverages. To prepare the poly(amino acid)-based sorbents, N-methacryloyl-l-phenylalanine methyl ester, and styrene served as the functional monomers and modified onto the magnetic nanoparticles via free radical polymerization. Interestingly, compared with propylparaben and potassium sorbate, the proposed poly(amino acid)-based sorbents showed a good selectivity to sodium benzoate. The adsorption capacity of the sorbents to sodium benzoate was 6.08 ± 0.31 mg/g. Moreover, the fast adsorption equilibrium could be reached within 5 min. Further, the resultant poly(amino acid)-based sorbents were applied in the analysis of sodium benzoate in real beverage samples. The results proved that the proposed magnetic solid-phase extraction sorbents have a great potential for the analysis of preservatives in food samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of thermosensitive poly(n-isopropylacrylamide-co-((2-dimethylamino) ethyl methacrylate))-based nanoparticles for controlled drug release

Energy Technology Data Exchange (ETDEWEB)

Peng, Cheng-Liang; Luo, Tsai-Yueh; Lin, Wuu-Jyh [Isotope Application Division, Institute of Nuclear Energy Research, PO Box 3-27, Longtan Taoyuan 325, Taiwan (China); Tsai, Han-Min; Yang, Shu-Jyuan; Lin, Chia-Fu; Shieh, Ming-Jium, E-mail: soloman@ntu.edu.tw [Institute of Biomedical Engineering, College of Medicine and College of Engineering, National Taiwan University, No 1, Section 1, Jen-Ai Road, Taipei 10051, Taiwan (China)

2011-07-01

Thermosensitive nanoparticles based on poly(N-isopropylacrylamide-co-((2-dimethylamino)ethylmethacrylate)) (poly(NIPA-co-DMAEMA)) copolymers were successfully fabricated by free radical polymerization. The lower critical solution temperature (LCST) of the synthesized nanoparticles was 41 deg. C and a temperature above which would cause the nanoparticles to undergo a volume phase transition from 140 to 100 nm, which could result in the expulsion of encapsulated drugs. Therefore, we used the poly(NIPA-co-DMAEMA) nanoparticles as a carrier for the controlled release of a hydrophobic anticancer agent, 7-ethyl-10-hydroxy-camptothecin (SN-38). The encapsulation efficiency and loading content of SN-38-loaded nanoparticles at an SN-38/poly(NIPA-co-DMAEMA) ratio of 1/10 (D/P = 1/10) were about 80% and 6.293%, respectively. Moreover, the release profile of SN-38-loaded nanoparticles revealed that the release rate at 42 deg. C (above LCST) was higher than that at 37 deg. C (below LCST), which demonstrated that the release of SN-38 could be controlled by increasing the temperature. The cytotoxicity of the SN-38-loaded poly(NIPA-co-DMAEMA) nanoparticles was investigated in human colon cancer cells (HT-29) to compare with the treatment of an anticancer drug, Irinotecan (CPT-11). The antitumor efficacy evaluated in a C26 murine colon tumor model showed that the SN-38-loaded nanoparticles in combination with hyperthermia therapy efficiently suppressed tumor growth. The results indicate that these thermo-responsive nanoparticles are potential carriers for controlled drug delivery.

Separación, purificación y caracterización de poli-hidroxibutirato

OpenAIRE

Grisel María Ortega-Arias-Carbajal; Antonio Bell-García

2014-01-01

La problemática generada por el uso indiscriminado de plásticos sintéticos y su persistencia en el ambiente ha estimulado la investigación para el desarrollo de nuevos materiales y procesos de produc- ción que permitan generar plásticos que presenten propiedades similares pero que tengan un período de degradación más corto. Entre estos materiales se encuentran los poli-hidroxialcanoatos, que constituyen polímeros biodegradables, siendo el poli- ß -hidroxibutirato, su forma más simple. El pres...

EUV lithographic radiation grafting of thermo-responsive hydrogel nanostructures

International Nuclear Information System (INIS)

Farquet, Patrick; Padeste, Celestino; Solak, Harun H.; Guersel, Selmiye Alkan; Scherer, Guenther G.; Wokaun, Alexander

2007-01-01

Nanostructures of the thermoresponsive poly(N-isopropyl acrylamide) (PNIPAAm) and of PNIPAAm-block-poly(acrylic acid) copolymers were produced on poly(tetrafluoroethylene-co-ethyelene) (ETFE) films using extreme ultraviolet (EUV) lithographic exposure with subsequent graft-polymerization. The phase transition of PNIPAAm nanostructures at the low critical solution temperature (LCST) at 32 deg. C was imaged by atomic force microscopy (AFM) phase contrast measurements in pure water. Results show a higher phase contrast for samples measured below the LCST temperature than for samples above the LCST, proving that the soft PNIPAAm hydrogel transforms into a much more compact conformation above the LCST. EUV lithographic exposures were combined with the reversible addition-fragment chain transfer (RAFT)-mediated polymerization using cyanoisopropyl dithiobenzoate (CPDB) as chain transfer agent to synthesize PNIPAAm block-copolymer nanostructures

Analysis of poly(styrene-co-methyl acrylate) and poly(styrene-co-butyl acrylate) by high-performance liquid chromatography

NARCIS (Netherlands)

Sparidans, R.W.; Claessens, H.A.; van Doremaele, G.H.J.; Herk, van A.M.

1990-01-01

Poly(styrene—co-methyl acrylate) and poly(styrene—co-butyl acrylate) were separated according to their chemical composition by gradient elution. The chromatographic separation on silica was optimized for a gradient ranging from n-heptane as a non-solvent to dichloromethane containing a small amount

Laser-ignited frontal polymerization of shape-controllable poly(VI-co-AM) hydrogels based on 3D templates toward adsorption of heavy metal ions

Science.gov (United States)

Fan, Suzhen; Liu, Sisi; Wang, Xiao-Qiao; Wang, Cai-Feng; Chen, Su

2016-06-01

Given the increasing heavy metal pollution issue, fast preparation of polymeric hydrogels with excellent adsorption property toward heavy metal ions is very attractive. In this work, a series of poly( N-vinylimidazole-co-acrylamide) (poly(VI-co-AM)) hydrogels were synthesized via laser-ignited frontal polymerization (LIFP) for the first time. The dependence of frontal velocity and temperature on two factors monomer ratios and initiator concentrations was systematically investigated. Poly(VI-co-AM) hydrogels with any self-supporting shapes can be synthesized by a one-step LIFP in seconds through the application of 3D templates. These shape-persistent hydrogels are pH-responsive and exhibit excellent adsorption/desorption characteristics toward Mn(II), Zn(II), Cd(II), Ni(II), Cu(II) and Co(II) ions, and the adsorption conformed to the pseudo-second-order kinetic model. The reusability of the hydrogels toward mental ions adsorption was further researched, which suggested that the hydrogels can be reused without serious decrease in adsorption capacity. This work might open a promising strategy to facilely prepare shape-controllable hydrogels and expand the application of LIFP.

Validation of two fluoro-analogues of N,N-dimethyl-2-(2'-amino-4'-hydroxymethyl-phenylthio)benzylamine as serotonin transporter imaging agents using microPET

Energy Technology Data Exchange (ETDEWEB)

Jarkas, Nachwa; Voll, Ronald J.; Williams, Larry [Department of Radiology, Emory CSI, WWHC, Atlanta, GA 30329 (United States); Goodman, Mark M., E-mail: mgoodma@emory.ed [Department of Radiology, Emory CSI, WWHC, Atlanta, GA 30329 (United States)

2010-07-15

Introduction: Carbon-11 (C-11) N,N-dimethyl-2-(2'-amino-4'-hydroxymethyl-phenylthio)benzylamine ([{sup 11}C]HOMADAM) has been reported as highly specific and selective positron emission tomography (PET) radiotracer showing fast kinetics for the human brain serotonin transporter (SERT). In our continued effort to develop appropriate PET SERT radioligand that can be labeled with either C-11 or fluorine-18 (F-18), two new C-11 labeled analogues of HOMADAM, [{sup 11}C]-N,N-dimethyl-2-(2'-amino-5'-fluoro-4'-hydroxymethyl-phenylthio) benzylamine ([{sup 11}C]-(2)) and [{sup 11}C]-N,N-dimethyl-2-(2'-amino-4-fluoro-4'-hydroxymethyl-phenylthio) benzylamine ([{sup 11}C]-(3)) have been synthesized and evaluated along the previously reported [{sup 11}C]-N,N-dimethyl-2-(2'-amino-5-fluoro-4'-hydroxymethyl-phenylthio) benzylamine ([{sup 11}C]-(1)). Methods: The in vitro competitive binding assays were performed in cells transfected with human SERT (hSERT), human dopamine transporter (hDAT), and human norepinephrine transporter (hNET). [{sup 11}C]-(2) and [{sup 11}C]-(3) were prepared by methylation of their monomethylbenzylamine precursors 13 and 22 with cyclotron produced [{sup 11}C]iodomethane ([{sup 11}C]CH{sub 3}I), respectively. Uptake and kinetics of [{sup 11}C]-(2) and [{sup 11}C]-(3) in the brain regions of interest were determined in anesthetized rhesus monkeys using Concorde microPET P4. Results: 2 and 3 displayed moderate and high affinity for the SERT with Kis (SERT) = 5.45 and 1.10 nM (vs [{sup 3}H]citalopram), respectively. After High Performance Liquid Chromatography (HPLC) purification, [{sup 11}C]-(2) and [{sup 11}C]-(3) were obtained in 23 and 9% radiochemical yield (RCY) and log Ps{sub 7.4} of 1.77 and 1.91, respectively. The microPET images of [{sup 11}C]-(2) and [{sup 11}C]-(3) showed clear localization in the monkey brain regions rich in SERT with midbrain to cerebellum ratios of 1.75 and 3.86 at 85 min post

Quantum mechanics/molecular mechanics modeling of covalent addition between EGFR-cysteine 797 and N-(4-anilinoquinazolin-6-yl) acrylamide.

Science.gov (United States)

Capoferri, Luigi; Lodola, Alessio; Rivara, Silvia; Mor, Marco

2015-03-23

Irreversible epidermal growth factor receptor (EGFR) inhibitors can circumvent resistance to first-generation ATP-competitive inhibitors in the treatment of nonsmall-cell lung cancer. They covalently bind a noncatalytic cysteine (Cys797) at the surface of EGFR active site by an acrylamide warhead. Herein, we used a hybrid quantum mechanics/molecular mechanics (QM/MM) potential in combination with umbrella sampling in the path-collective variable space to investigate the mechanism of alkylation of Cys797 by the prototypical covalent inhibitor N-(4-anilinoquinazolin-6-yl) acrylamide. Calculations show that Cys797 reacts with the acrylamide group of the inhibitor through a direct addition mechanism, with Asp800 acting as a general base/general acid in distinct steps of the reaction. The obtained reaction free energy is negative (ΔA = -12 kcal/mol) consistent with the spontaneous and irreversible alkylation of Cys797 by N-(4-anilinoquinazolin-6-yl) acrylamide. Our calculations identify desolvation of Cys797 thiolate anion as a key step of the alkylation process, indicating that changes in the intrinsic reactivity of the acrylamide would have only a minor impact on the inhibitor potency.

Thermo-responsive polymer-functionalized mesoporous carbon for controlled drug release

Energy Technology Data Exchange (ETDEWEB)

Zhu Shenmin, E-mail: smzhu@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Chen Chenxin [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Chen Zhixin [Faculty of Engineering, University of Wollongong, Wollongong, NSW 2522 (Australia); Liu Xinye; Li Yao; Shi Yang; Zhang Di [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

2011-03-15

Research highlights: {yields} A responsive drug delivery system based on poly(N-isopropyl acrylamide) (PNIPAM) functionalized ordered mesoporous carbon (CMK-3) is developed. {yields} A combination of surface modification of CMK-3 and in situ internal polymerization of PNIPAM was used. {yields} The system exhibited a pronounced transition at around 20-25 deg. C. - Abstract: A novel responsive drug delivery system based on poly(N-isopropyl acrylamide) (PNIPAM) functionalized ordered mesoporous carbon (CMK-3) is developed. The polymer-functionalized CMK-3 was obtained by a combination of simple surface modification of CMK-3 and in situ internal polymerization of PNIPAM. The formation of the PNIPAM inside the CMK-3 was confirmed by thermal gravimetric analysis, Fourier transform-infrared spectroscopy, scanning and transmission electron microscopy and N{sub 2} adsorption/desorption measurements. Controlled drug release tests through the porous network of the PNIPAM functionalized CMK-3 were carried out by measuring the uptake and release of ibuprofen in vitro. The release profiles exhibited a pronounced transition at around 20-25 deg. C. This thermo-sensitive release property of this delivery system was further confirmed by temperature-variable hydrogen nuclear magnetic resonance analysis. The internal PNIPAM layers acted as a storage gate as well as a release switch in response to the stimuli of environment.

Synthesis and Characterization of Poly (ether imide)s Containing Phthalazinone and Isopropyl Moieties

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

A novel poly(ether imide)s containing phthalazinone and isopropyl moieties derived from 2-(4-aminophenyl)-4-[4-(4-aminophenoxy)phenyl]-phthalazin-l-one and bisphenol-A diphthalic anhydride was synthesized by one-step solution condensation polymerization in m-cresol. The polymer was characterized by FTIR, NMR, molecular weights, glass transition temperature,thermal degradation temperature and WAXD.

New membranes obtained by grafted irradiated PVDF foils

International Nuclear Information System (INIS)

Mazzei, R.; García Bermúdez, G.; Camporotondi, D.E.; Arbeitman, C.

2012-01-01

The present work describes a new method to produce membranes of poly(Acrylic-acid-Xmonomer) using the grafting procedure. PVDF foils irradiated with Ar + beam with energies between 30 and 150 keV were employed as substratum. Different combinations of monomers in water solutions were used: acrylic acid (AAc); acrylic acid–glycidyl methacrylate (AAc–GMA); acrylic acid–styrene (AAc–S), acrylic acid-N-isopropyl acrylamide (AAc–NIPAAm) and acrylic acid-N-isopropyl acrylamide–glycidyl methacrylate (AAc-NIPAAm–GMA). A large percentage of grafting results for specific values of: ion fluence and energy, AAc and sulfuric acid concentration, and different substrata PVDF polymorphous (alpha or beta). At a particular time of the grafting process, the poly(AAc-Xmonomer) membranes detach from the substratum and continue their grafting in the solution. This method is useful to produce increased replicated membranes of the irradiated original surface.

Brain perfusion image using N-isopropyl-p-(/sup 123/I) iodoamphetamine. Detection of interhemispheric difference

Energy Technology Data Exchange (ETDEWEB)

Matsuda, Hiroshi; Seki, Hiroyasu; Ishida, Hiroko

1984-12-01

In brain perfusion images using N-isopropyl-p-(/sup 123/I)iodoamphetamine and rotating gamma camera emission computed tomography, brain maps showing laterality indices (LI) were made for the purpose of detecting intrahemispheric differences. Left (L) and right (R) leteral images were made by adding sagittal section images in each hemisphere, respectively. LI was calculated as follows. LI=100(1 + (R-L)/(R + L)). The normal ranges (mean +- 2 s.d.) of the indices determined by those obtained in five normal right-handed subjects were 103 +- 4 and 103 +- 10 for brain mean and each pixel, respectively. Out of 25 measurements in 22 right-handed patients with cerebrovascular accidents, brain mean LI beyond the normal limits and areas showing abnormal regional LI were observed in 5 (20%) and 21 (84%) measurements, respectively. On the other hand, X-ray CT showed low density areas in only 12 (48%). These brain maps were clinically useful for detecting and quantifying interhemispheric differences in brain perfusion images with N-isopropyl-p-(/sup 123/I)iodoamphetamine. (author). Contains 48 refs.

Triazine containing N-rich microporous organic polymers for CO2 capture and unprecedented CO2/N2 selectivity

International Nuclear Information System (INIS)

Bhunia, Subhajit; Bhanja, Piyali; Das, Sabuj Kanti; Sen, Tapas; Bhaumik, Asim

2017-01-01

Targeted synthesis of microporous adsorbents for CO 2 capture and storage is very challenging in the context of remediation from green house gases. Herein we report two novel N-rich microporous networks SB-TRZ-CRZ and SB-TRZ-TPA by extensive incorporation of triazine containing tripodal moiety in the porous polymer framework. These materials showed excellent CO 2 storage capacities: SB-TRZ-CRZ displayed the CO 2 uptake capacity of 25.5 wt% upto 1 bar at 273 K and SB-TRZ-TPA gave that of 16 wt% under identical conditions. The substantial dipole quadruple interaction between network (polar triazine) and CO 2 boosts the selectivity for CO 2 /N 2 . SB-TRZ-CRZ has this CO 2 /N 2 selectivity ratio of 377, whereas for SB-TRZ-TPA it was 97. Compared to other porous polymers, these materials are very cost effective, scalable and very promising material for clean energy application and environmental issues. - Graphical abstract: We report two novel N-rich microporous polymeric materials by doping of triazine containing tripodal dopant in the organic framework. These materials showed excellent CO 2 storage capacities as high as 25.5 wt% under 1 bar pressure with exceptional CO 2 /N 2 selectivity of 377. - Highlights: • Triazine containing trimodal moiety incorporated in polycarbazolic and poly triphenylamine networks. • N-rich crosslinked polymers with high BET surface area and 1.5–1.7 nm size large micropores. • CO 2 uptake capacity of 25.5 wt% upto 1 bar at 273 K. • These crosslinked porous polymers showed exceptional CO 2 /N 2 selectivity.

Synthesis and characterization of biodegradable poly (ethylene glycol) and poly (caprolactone diol) end capped poly (propylene fumarate) cross linked amphiphilic hydrogel as tissue engineering scaffold material.

Science.gov (United States)

Krishna, Lekshmi; Jayabalan, Muthu

2009-12-01

Biodegradable poly (caprolactone diol-co-propylene fumarate-co-ethylene glycol) amphiphilic polymer with poly (ethylene glycol) and poly (caprolactone diol) chain ends (PCL-PPF-PEG) was prepared. PCL-PPF-PEG undergoes fast setting with acrylamide (aqueous solution) by free radical polymerization and produces a crosslinked hydrogel. The cross linked and freeze-dried amphiphilic material has porous and interconnected network. It undergoes higher degree of swelling and water absorption to form hydrogel with hydrophilic and hydrophobic domains at the surface and appreciable tensile strength. The present hydrogel is compatible with L929 fibroblast cells. PCL-PPF-PEG/acrylamide hydrogel is a candidate scaffold material for tissue engineering applications.

Study of poly (acrylamide-co-2-acrylamido-2-methylpropane sulfonic acid) hydrogel using gamma radiation initiation

International Nuclear Information System (INIS)

Zhang, C.; Easteal, A.J.

1998-01-01

Full text: Poly (acrylamide-co-2-acrylamido-2-methylpropane sulfonic acid ) (PAAM-co-AMPS) polyelectrolyte hydrogels were formed by using γ-radiation to initiate polymerization and cross-linking. The dependence of chain growth and cross-linking of liquid-like gel on absorbed dose was observed by viscosity measurement. It was found that the viscosity of liquid-like gel increased non-linearly with increasing radiation dose. Crosslinking took place at about 2,300 Gy. It was noted that an ageing effect occurred, such that the viscosity of liquid-like gels decreased significantly on standing. X-ray diffraction revealed that after dehydration the dried gels were amorphous, suggesting that radiation polymerization occurs by random initiation and propagation. Differential scanning calorimetry (DSC) indicated a clear distinction between the thermal behaviour of the homopolymer gels formed by irradiation, and the behaviour of the copolymer gels. PAAM-co-AMPS gels have enhanced thermal stability in comparison to PAAM and PAMPS. The melting points of water in the gels initially increase with increasing dose, and decrease slightly at very high radiation dose. Those trends can be explained by the variation in the numbers of solute molecules or ions in the gels with absorbed dose. Melting points of water in gels can be used for observation of the polymerization process associated with irradiation. Copolymer composition (expressed by either f 1 (AAM molal fraction ) or f 2 (AMPS molal fraction) ) associated with radiation dose was determined by both elemental analysis and FTIR. Both methods show that f 1 increases to a maximum with increasing dose, and subsequently decreases. It is concluded that PAAM-co-AMPS hydrogels were synthesised successfully by gamma radiation initiation, and that copolymer compositions are dependent on radiation dose

Temperature-induced phase transition in hydrogels of interpenetrating networks poly(N-isopropylmethacrylamide)/poly(N-isopropylacrylamide)

Czech Academy of Sciences Publication Activity Database

Šťastná, J.; Hanyková, L.; Sedláková, Zdeňka; Valentová, H.; Spěváček, Jiří

2013-01-01

Roč. 291, č. 10 (2013), s. 2409-2417 ISSN 0303-402X R&D Projects: GA ČR GA202/09/1281 Institutional support: RVO:61389013 Keywords : temperature-induced volume phase transition * poly (N-isopropylmethacrylamide) poly (Nisopropylacrylamide) interpenetrating network * 1H NMR spectroscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.410, year: 2013

Magnetocaloric effect in magnetothermally-responsive nanocarriers for hyperthermia-triggered drug release

International Nuclear Information System (INIS)

Li Jianbo; Qu Yang; Ren Jie; Yuan Weizhong; Shi Donglu

2012-01-01

The magnetocaloric effects and lower critical solution temperature (LCST) were investigated in a magnetothermally-responsive nanocarrier for magnetothermal drug release under alternating magnetic field (AMF). The Mn 0.2 Zn 0.8 Fe 2 O 4 nanoparticles with low T c were dispersed in a polymeric matrix consisting of N-Isopropyl acrylamide (NIPAAm) and N-hydroxymethyl acrylamide (HMAAm). The magnetocaloric effects and LCST of the nanocarriers were characterized by using high-resolution electron transmission microscopy, thermogravimetric analyses, and vibrating sample magnetometer. The maximum self-heating temperature of 42.9 °C was achieved by optimizing the Mn 0.2 Zn 0.8 Fe 2 O 4 concentration in the polymer matrix. By adjusting the NIPAAm to HMAAm ratio, the LCST was controlled at an ideal level of 40.1 °C for efficient thermosensitive drug delivery. Magnetothermally responsive drug release of Doxorubicin, an anticancer drug, was significantly enhanced by application of an external AMF on the nanocarriers. The cytotoxicity experimental results in vitro show good biocompatibility and efficient therapeutic effects in cancer treatment. (paper)

Activismo, política y subversión en la literatura niuyorriqueña: del programa poético-político de Miguel Algarín a la poética menor de Tato Laviera

OpenAIRE

Alejo López

2014-01-01

Este trabajo se propone dar cuenta de la relación entre poesía y política desarrollada por la tradición literaria niuyorriqueña. A partir de un análisis comparativo de las diversas modulaciones a través de las cuales esta relación fundamental se configuró en la obra de un corpus de autores emblemáticos de la primera generación niuyorriqueña, intentaremos demostrar cómo esta relación entre poesía y política oscila entre una modulación agonística de carácter contestatario y o...

N-isopropyl I-123 p-iodoamphetamine (IMP) brain SPECT in Alzheimer's disease

Energy Technology Data Exchange (ETDEWEB)

Momose, Toshimitsu; Nishikawa, Junichi; Kosaka, Noboru; Ohtake, Tohru; Watanabe, Toshiaki; Yoshikawa, Kohki; Iio, Masahiro [Tokyo Univ. (Japan). Faculty of Medicine

1989-09-01

Eighteen patients with Alzheimer's disease (AD), 5 patients with Pick disease (PD), 6 patients with other types of degenerative dementia (O) and 12 age-matched normal control subjects (N) were studied using N-isopropyl p-(I-123)iodoamphetamine (I-123 IMP) with SPECT. Regional to cerebellar activity (R/CE) ratio and frontal to parietal (F/R) activity ratio were evaluated in each case. I-123 IMP-SPECT revealed focal abnormality in all cases in AD, PD, O group, while XCT and/or MRI were normal or showed cerebral atrophy without focal abnormal density or intensity. In AD group, R/CE ratio in all the regions except for bilateral Rolandic area and left primary visual cortex were significantly lower (p<0.05 or p<0.01) than that in N group, and F/P ratio were significantly higher (p<0.01) than that in P and O group. In conclusion, I-123 IMP-SPECT is useful to detect focal perfusion abnormality in dementia and may be of value in differentiating Alzheimer's disease from dementia of non-Alzheimer type. (author).

N-isopropyl I-123 p-iodoamphetamine (IMP) brain SPECT in Alzheimer's disease

International Nuclear Information System (INIS)

Momose, Toshimitsu; Nishikawa, Junichi; Kosaka, Noboru; Ohtake, Tohru; Watanabe, Toshiaki; Yoshikawa, Kohki; Iio, Masahiro

1989-01-01

Eighteen patients with Alzheimer's disease (AD), 5 patients with Pick disease (PD), 6 patients with other types of degenerative dementia (O) and 12 age-matched normal control subjects (N) were studied using N-isopropyl p-[I-123]iodoamphetamine (I-123 IMP) with SPECT. Regional to cerebellar activity (R/CE) ratio and frontal to parietal (F/R) activity ratio were evaluated in each case. I-123 IMP-SPECT revealed focal abnormality in all cases in AD, PD, O group, while XCT and/or MRI were normal or showed cerebral atrophy without focal abnormal density or intensity. In AD group, R/CE ratio in all the regions except for bilateral Rolandic area and left primary visual cortex were significantly lower (p<0.05 or p<0.01) than that in N group, and F/P ratio were significantly higher (p<0.01) than that in P and O group. In conclusion, I-123 IMP-SPECT is useful to detect focal perfusion abnormality in dementia and may be of value in differentiating Alzheimer's disease from dementia of non-Alzheimer type. (author)

SPECT brain imaging with N-isopropyl [123I]-p-iodoamphetamine

International Nuclear Information System (INIS)

Holman, B.L.; Hill, T.C.; Magistretti, P.L.

1985-01-01

N-isopropyl-[ 123 I]-p-iodoamphetamine is a lipophilic tracer that passes readily across the blood-brain barrier and is retained long enough to permit planar and tomographic imaging. Its distribution in the brain is proportional to blood flow, and its brain concentration remains unchanged between 30 min and 1 hr after intravenous injection. Tomographic imaging demonstrates increased activity in the gray matter, basal ganglia, and thalamus as would be expected with a cerebral perfusion tracer. In patients with acute cerebral infarction, decreased perfusion occurs immediately with the onset of symptoms. The technique also has utility in epilepsy in defining the abnormal focus in patients with medically intractable temporal-lobe epilepsy. This technique should prove to be a routine nuclear medicine procedure for the evaluation of cerebral perfusion

Síntesis y almacenamiento de carga de la nueva aleación polipirrol/poli(ácido maleico-olefina

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D´eramo, F.

2000-06-01

Full Text Available The influence that the electrosynthesis conditions of the polypyrrole/poly(maleic acid-co-olefin blend have on the charge storage ability (amount of electrical charge stored (mC per unit mass (mg of electrogenerated polymer has been analysed. This is the initial step for the optimisation, pyrrole and poly (maleic acid-co-olefin concentrations and the polymerisation temperature have been the studied parameters. Optimising these ones, we could obtain materials with average storage charge of 120mc.mg-1.

Se ha analizado la influencia de diversas variables de síntesis sobre la capacidad de almacenamiento de carga (mC de carga almacenada / mg de polímero electrogenerado de aleaciones poliméricas de polipirrol/poli(ácido maléico-co-olefina, como paso inicial para la optimación de este material para su aplicación en baterías todo orgánicas. Las variables de estudio han sido: el potencial y el tiempo de polimerización, las concentraciones de pirrol y poli(ácido maléico-co-olefina y la temperatura de la solución de polimerización. Optimando estos parámetros se ha logrado sintetizar materiales con una capacidad promedio de almacenamiento de carga de 120 mC. mg-1.

Toxicology and carcinogenesis studies of acrylamide (CASRN 79-06-1) in F344/N rats and B6C3F1 mice (feed and drinking water studies).

Science.gov (United States)

2012-07-01

Acrylamide, a water-soluble α,β-unsaturated amide, is a contaminant in baked and fried starchy foods, including french fries, potato chips, and bread, as a result of Maillard reactions involving asparagine and reducing sugars. Additional sources of acrylamide exposure include cigarettes, laboratory procedures involving polyacrylamide gels, and various occupations (e.g, monomer production and polymerization processes). Acrylamide is carcinogenic in experimental animals. To obtain data for developing quantitative risk assessments for dietary exposures to acrylamide, the Food and Drug Administration nominated acrylamide for an in-depth toxicological evaluation by the National Toxicology Program. As part of this evaluation, male and female B6C3F1/Nctr (C57BL/6N x C3H/HeN MTV-) mice and male and female F344/N Nctr rats were exposed to acrylamide (at least 99.4% pure) in drinking water for 2 years. 2-WEEK STUDY IN RATS: Groups of four male and four female F344/N rats were administered 0, 0.14, 0.35, 0.70, 1.41, 3.52, or 7.03 mM acrylamide in the drinking water (0, 10, 25, 50, 100, 250, or 500 ppm acrylamide) or 0.0, 7.4, 18.5, 37, 74, 185, or 370 mg acrylamide per kg diet for 14 days. One male rat administered 7.03 mM acrylamide in the drinking water died on day 14. Male and female rats receiving 7.03 mM acrylamide weighed 56% and 64% of controls, respectively. Male and female rats fed 370 mg acrylamide per kg diet weighed 74% and 83% of controls, respectively. Female rats receiving 3.52 mM acrylamide in drinking water and male rats fed 185 mg acrylamide per kg diet weighed 85% and 89% of controls, respectively. Rats receiving 7.03 mM acrylamide in drinking water or 370 mg acrylamide per kg diet exhibited hind-leg paralysis on day 14. Mild to moderate dilatation of the urinary bladder was observed in all rats given 370 mg acrylamide per kg diet, and in three of four male rats and all four female rats given 7.03 mM acrylamide in drinking water, and in one of four male

Poly(N-isopropylacrylamide-co-methacrylic acid microgel stabilized copper nanoparticles for catalytic reduction of nitrobenzene

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Farooqi Zahoor H.

2015-09-01

Full Text Available Poly(N-isopropylacrylamide-co-methacrylic acid microgels [p(NIPAM-co-MAAc] were synthesized by precipitation polymerization of N-isopropylacrylamide and methacrylic acid in aqueous medium. These microgels were characterized by dynamic light scattering and Fourier transform infrared spectroscopy. These microgels were used as micro-reactors for in situ synthesis of copper nanoparticles using sodium borohydride (NaBH4 as reducing agent. The hybrid microgels were used as catalysts for the reduction of nitrobenzene in aqueous media. The reaction was performed with different concentrations of cat­alyst and reducing agent. A linear relationship was found between apparent rate constant (kapp and amount of catalyst. When the amount of catalyst was increased from 0.13 to 0.76 mg/mL then kapp was increased from 0.03 to 0.14 min-1. Activation parameters were also determined by performing reaction at two different temperatures. The catalytic process has been discussed in terms of energy of activation, enthalpy of activation and entropy of activation. The synthesized particles were found to be stable even after 14 weeks and showed catalytic activity for the reduction of nitrobenzene.

Globalización de la política pública: mediación neoliberal en Colombia, política económica, 1990-2006

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Adolfo Rodríguez Bernal

2007-01-01

Full Text Available La transnacionalización de la política pública en la década de los 80, es resultado de tres cambios notables operados en el orden mundial: reconfiguración del escenario global, en lo conflictual geográfico y económico, reordenamiento en el modelo de mercado y transformación en el ciclo de política pública. Estos cambios están asociados a la caracterización del espacio geográfico económico, desigual y desequilibrado; a la construcción del nuevo referencial del mercado en la reorientación de la acción pública y al cambio en la expansión del ciclo de política pública en el escenario mundial. El modelo global de mercado, en su proyección transnacional, ha servido de directriz a la mediación de la política económica de los gobiernos neoliberales en Colombia, 1990-2006, en el proceso de su adopción, adaptación y ajuste con el fin de garantizar su ejecución e implementación. La aceptación obligada o la imposición “negociada” de la política económica nacional pasa por la adopción de política financiera, condicionada por el endeudamiento externo; la adaptación de la transferencia de tecnología como política productiva; y, la cesión del mercado interior a las ETN. Las tendencias observadas, fundamentan la nueva estructura de mercado con capacidad explicativa de sus resultados, en escenarios financieros, productivos y comerciales. Las consecuencias para Colombia se traducen en crecimiento del endeudamiento financiero, acelerada desindustrialización del país y reducción del mercado ante las transnacionales. En esta situación, todo proyecto nacional resulta utópico por la pérdida de soberanía económica para la industrialización, para el manejo y control de los recursos naturales y para garantizar la seguridad alimentaria y espacios del mercado necesarios a su avance.

Radiation preparation of drug carriers based on poly(N-isopropylacrylamide) hydrogels, their loading capacities and controlled release rates for dexamethasone and tegafur

International Nuclear Information System (INIS)

Hoang Dang Sang; Nguyen Van Binh; Tran Bang Diep; Nguyen Thi Thom; Hoang Phuong Thao; Pham Duy Duong; Tran Minh Quynh

2015-01-01

Thermo-sensitive hydrogels have great potential in some applications. In order to use as the drug delivery systems, the hydrogels should be biocompatibility. New polymers with more biocompatibility and better biodegradability, and environmental friendly crosslinking agents would be necessary for the successful drug carriers. Poly (N-isopropylacrylamide-co-dimethylacrylamide) based hydrogels have been prepared from the admixture solutions of N-isopropylacrylamide (NIPA) and N,N’-dimethyl acrylamide (DMA) by radiation copolymerization and crosslinking at radiation dose of 20 kGy as reported in our previous study. Water swelling behaviour of the resulting hydrogels were much depended on their nature such as initial ratio of NIPA and DMA. The drug-loaded hydrogels were prepared by merging hydrogel in the solutions containing corresponding drugs. Loading capacity of the hydrogels were about 48.6 and 95.7 mg per g dried hydrogel for dexamethasone and tegafur. The release studies showed that the presence of ions in simulated body fluid and temperature of the solution much affecting to in vitro release behaviors of hydrogels for dexamethasone and tegafur. The release rates were fast for both drug models. The result also revealed that these drug carriers were biocompatibility without skin irritation, suggested the drug-loaded hydrogels may be used as controlled release drug delivery systems. (author)

CO2-selective PEO–PBT (PolyActive™)/graphene oxide composite membranes

KAUST Repository

Karunakaran, Madhavan; Shevate, Rahul; Kumar, Mahendra; Peinemann, Klaus-Viktor

2015-01-01

CO2-selective graphene oxide (GO) nano-composite membranes were prepared for the first time by embedding GO into a commercially available poly(ethylene oxide)–poly(butylene terephthalate) (PEO–PBT) copolymer (PolyActive™). The as-prepared GO membrane shows high CO2 permeability (143 Barrer) and CO2/N2 selectivity (α = 73).

CO2-selective PEO–PBT (PolyActive™)/graphene oxide composite membranes

KAUST Repository

Karunakaran, Madhavan

2015-07-31

CO2-selective graphene oxide (GO) nano-composite membranes were prepared for the first time by embedding GO into a commercially available poly(ethylene oxide)–poly(butylene terephthalate) (PEO–PBT) copolymer (PolyActive™). The as-prepared GO membrane shows high CO2 permeability (143 Barrer) and CO2/N2 selectivity (α = 73).

Complexation of anionic copolymers of acrylamide and N-(2-hydroxypropyl)methacrylamide with aminoglycoside antibiotics

Science.gov (United States)

Solovskii, M. V.; Tarabukina, E. B.; Amirova, A. I.; Zakharova, N. V.; Smirnova, M. Yu.; Gavrilova, I. I.

2014-03-01

The complexation of aminoglycoside antibiotics neomycin, gentamicin, kanamycin, and amikacin in the form of free bases with carboxyl- and sulfo-containing copolymers of acrylamide and N-(2-hydroxypropyl)methacrylamide (HPMA) in water and water-salt solutions is studied by means of viscometry, equilibrium dialysis, potentiometric titration, and molecular hydrodynamics. Factors influencing the stability of formed copolymer-antibiotic complexes and determinations of their toxicity are established.

Poly(N-isopropylacrylamide)–poly(ferrocenylsilane) dual-responsive hydrogels: synthesis, characterization and antimicrobial applications

NARCIS (Netherlands)

Sui, Xiaofeng; Feng, Xueling; Di Luca, Andrea; van Blitterswijk, Clemens; Moroni, Lorenzo; Hempenius, Mark A.; Vancso, Gyula J.

2013-01-01

Novel hydrogels composed of thermo-responsive poly(N-isopropylacrylamide) (PNIPAM) and redox-responsive poly(ferrocenylsilane) (PFS) macromolecules were formed by photopolymerization. PFS chains bearing acrylate side groups were copolymerized with NIPAM and N,N′-methylenebisacrylamide in

Triazine containing N-rich microporous organic polymers for CO{sub 2} capture and unprecedented CO{sub 2}/N{sub 2} selectivity

Energy Technology Data Exchange (ETDEWEB)

Bhunia, Subhajit; Bhanja, Piyali; Das, Sabuj Kanti [Department of Material Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Sen, Tapas [Nanobiomaterials Research Group, Centre for Materials Science, School of Physical Sciences and Computing, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Bhaumik, Asim, E-mail: msab@iacs.res.in [Department of Material Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India)

2017-03-15

Targeted synthesis of microporous adsorbents for CO{sub 2} capture and storage is very challenging in the context of remediation from green house gases. Herein we report two novel N-rich microporous networks SB-TRZ-CRZ and SB-TRZ-TPA by extensive incorporation of triazine containing tripodal moiety in the porous polymer framework. These materials showed excellent CO{sub 2} storage capacities: SB-TRZ-CRZ displayed the CO{sub 2} uptake capacity of 25.5 wt% upto 1 bar at 273 K and SB-TRZ-TPA gave that of 16 wt% under identical conditions. The substantial dipole quadruple interaction between network (polar triazine) and CO{sub 2} boosts the selectivity for CO{sub 2}/N{sub 2}. SB-TRZ-CRZ has this CO{sub 2}/N{sub 2} selectivity ratio of 377, whereas for SB-TRZ-TPA it was 97. Compared to other porous polymers, these materials are very cost effective, scalable and very promising material for clean energy application and environmental issues. - Graphical abstract: We report two novel N-rich microporous polymeric materials by doping of triazine containing tripodal dopant in the organic framework. These materials showed excellent CO{sub 2} storage capacities as high as 25.5 wt% under 1 bar pressure with exceptional CO{sub 2}/N{sub 2} selectivity of 377. - Highlights: • Triazine containing trimodal moiety incorporated in polycarbazolic and poly triphenylamine networks. • N-rich crosslinked polymers with high BET surface area and 1.5–1.7 nm size large micropores. • CO{sub 2} uptake capacity of 25.5 wt% upto 1 bar at 273 K. • These crosslinked porous polymers showed exceptional CO{sub 2}/N{sub 2} selectivity.

Activismo, política y subversión en la literatura niuyorriqueña: del programa poético-político de Miguel Algarín a la poética menor de Tato Laviera

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Alejo López

2014-01-01

Full Text Available Este trabajo se propone dar cuenta de la relación entre poesía y política desarrollada por la tradición literaria niuyorriqueña. A partir de un análisis comparativo de las diversas modulaciones a través de las cuales esta relación fundamental se configuró en la obra de un corpus de autores emblemáticos de la primera generación niuyorriqueña, intentaremos demostrar cómo esta relación entre poesía y política oscila entre una modulación agonística de carácter contestatario y otra que sostiene su politicidad a través de la configuración de una literatura menor en su sentido deleuzeano. La poesía niuyorriqueña es definida por sus fundadores (Algarín, Esteves como “una afirmación de lucha política” , entendida esta como la oposición confrontativa contra las fuerzas sociales que recluyen a la comunidad a una posición marginal. Sin embargo figuras como las de Víctor Hernández Cruz o Tato Laviera pre- sentan una modulación diferente de esta articulación agonística entre literatura y política, especialmente Laviera, en cuya obra no encontramos una articulación entre poesía y política en tanto praxis diferenciadas, sino que ambas se hallan integradas en un mismo nivel a través de la configuración de una lengua y una identidad inasimilables e indómitas, en tanto instru- mentos de resistencia frente a los sistemas de asimilación y marginalización, lo que deviene, finalmente, en la constitución de una “literatura menor” , un tipo de literatura cuya potencia política surge del trabajo contrahegemónico de una lengua menor dentro de otra mayor.

Synthesis, labelling and biodistribution of N-isopropyl 131I-p-iodoamhetamine (131IAMP)

International Nuclear Information System (INIS)

Godoy, N.; Reveco, P.; Mena, P.; Gil, M.C.

1986-01-01

It is possible to synthesize N-isopropyl-p-iodoamphetamine (IAMP) through differents schemes, being the most feasible the iodination of phenylacetic acid. The labelling of this compound with radioidine, by isotope exchange in presence or absence of Cu (II) as catalyst, presents less activity concentration in brain than using Cu (II) with an excess of ascorbic acid as reducing agent of Cu (II). The use of ascorbic acid in excess allow the formation of Cu (I) in-situ, which may form an Ar-Cu-I complex, favouring the isotope nucleophilic substitution reaction, obtaining 131 IAMP higher radiochemical purity and better cerebral uptake. (Author)

Synergetic effect of green tea on polymer gel dosimeter and determination of optimal wavelength to choose light source for optical computed tomography

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Sathiya Raj

2016-03-01

Full Text Available Purpose: The ultimate aim of this study is to observe the effect of Green tea as a co-antioxidant in PAGAT gel dosimeter and evaluate the appropriate light source for scanning the PAGAT and NIPAM polymer gel.Methods: Both PAGAT (Poly Acrylamide Gelatin Tetrakis hydroxyl phosphonium chloride and NIPAM (N-Isopropyl acrylamide gel were prepared in normoxic condition. The green tea extract (GTE was prepared and tested only on PAGAT. Co-60 teletherapy machine has been used for irradiation purpose, and the gel samples were scanned using UV-Visible spectrophotometer. Water equivalency of the gel has been tested in terms of their electron density, effective atomic number and Ratio of oxygen and hydrogen (O/H. We have used NIST XCOM database to test the water equivalency.Results: In this study we found that the GTE added to the gel do not respond to the given doses. By adding sugar we can enhance the sensitivity of the gel. Further investigations are required to use Green tea as a co antioxidant concentration of THPC (Tetrakis hydroxymethyl phosphonium chloride. The optimal wavelength with different region for scanning the PAGAT is 450 to 480 nm (Blue region, for NIPAM it is 540 nm and 570 nm (Green and yellow region. The PAGAT and NIPAM showed better sensitivity at 510 nm. Both gels have their effective atomic number closer to water (NIPAM-7.2, PAGAT-7.379.Conclusion: As per our results, we concluded that GTE alone is not an effective co-antioxidant for polymer gels. When the GTE is combined with sugar and THPC, it protects the gel from pre-polymerization. This study strongly suggests that the blue light is an optimal source for scanning the PAGAT and green to yellow light for NIPAM gel. Though both gels were considered as water equivalent, the PAGAT is equivalent to water and the temporal stability of this gel is higher than NIPAM.

N-isopropyl-p-iodoamphetamine receptors in normal and cancerous tissue of the human lung

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Eiko; Mishima, Michiaki; Kawakami, Kenzo; Sakai, Naoki; Sugiura, Naoharu; Kuno, Kenshi [Kyoto Univ. (Japan). Dept. of Clinical Physiology; Taniguchi, Takashi [Kyoto Pharmaceutical Univ. (Japan). Dept. of Neurobiology

1993-04-01

N-Isopropyl-p-iodoamphetamine (IMP) receptors in normal human lung tissue were characterized using a radioligand binding assay with iodine-125 IMP as the ligand. Saturation binding studies revealed the presence of two binding sites with dissociation constant (K[sub d]) values of 53[+-]2 and 4687[+-]124 nM and maximum binding capacity (Bmax) values of 7[+-]1 and 133[+-]27 pmol/mg protein (n=5) respectively. The IC[sub 50] values of various amines were as follows: IMP, 9x10[sup -5] M; propranolol, 5x10[sup -4] M; haloperidol, 6x10[sup -4] M; ketamine, 9x10[sup -3] M; dopamine, 1x10[sup -2] M. The IMP receptors of cancerous tissue obtained from human lung also had two binding sites with K[sub d] values of 54[+-]2 and 5277[+-]652 nM and Bmax values of 7[+-]1 and 103[+-]21 pmol/mg protein (n=3) respectively. There was no significant difference in binding parameters between normal and cancerous lung tissue. These results demonstrate the existence of IMP receptors and suggest that cancer does not affect the nature of IMP receptors in human lung tissue. (orig.).

Isothermal titration calorimetric studies of the acid-base properties of poly(N-isopropylacrylamide-co-4-vinylpyridine) cationic polyelectrolyte colloidal microgels

International Nuclear Information System (INIS)

Seidel, J.; Pinkrah, V.T.; Mitchell, J.C.; Chowdhry, B.Z.; Snowden, M.J.

2004-01-01

Isothermal titration calorimetry (ITC) and potentiometric titration were used to study the protonation properties of the 4-vinylpyridine (4-VP) moiety in cationic poly(N-isopropylacrylamide-co-4-vinylpyridine) colloidal microgels [poly(NIPAM-co-4-VP)]. Calorimetric pH titrations were performed using microgels of different 4-VP content and the influence of ionic strength and counter ions have been examined. The calorimetric titration output consists of several thermal contributions reflecting the complex nature of the interactions in the aqueous microgel dispersions. In contrast to the potentiometric results, the calorimetric titration data could not be completely described by a theoretical model solely taking into account protonation equilibria. Deviations from the proposed model correlate with swelling or shrinking of the gel particles. The calorimetric results also reveal a pronounced counter-ion effect of perchlorate compared to chloride ions. In the presence of perchlorate ions, small secondary thermal effects accompany protonation of the 4-VP moiety due, in part, to kinetically limited conformational changes in the co-polymer microgel

Microstructures of poly(N-methylpyrrole) and their interaction with morphine

Energy Technology Data Exchange (ETDEWEB)

Teixeira-Dias, Bruno [Departament d' Enginyeria Quimica, ETSEIB, Universitat Politecnica de Catalunya, Av. Diagonal 647, 08028, Barcelona (Spain); Center for Research in Nanoengineering, Universitat Politecnica de Catalunya, Campus Sud, Edifici C' , C/Pasqual i Vila s/n, 08028, Barcelona (Spain); Aleman, Carlos, E-mail: carlos.aleman@upc.edu [Departament d' Enginyeria Quimica, ETSEIB, Universitat Politecnica de Catalunya, Av. Diagonal 647, 08028, Barcelona (Spain); Center for Research in Nanoengineering, Universitat Politecnica de Catalunya, Campus Sud, Edifici C' , C/Pasqual i Vila s/n, 08028, Barcelona (Spain); Estrany, Francesc [Center for Research in Nanoengineering, Universitat Politecnica de Catalunya, Campus Sud, Edifici C' , C/Pasqual i Vila s/n, 08028, Barcelona (Spain); Unitat de Quimica Industrial, EUETIB, Universitat Politecnica de Catalunya, Comte d' Urgell 187, 08036, Barcelona (Spain); Azambuja, Denise S. [Institute of Chemistry, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500 - CEP 91501-970, Porto Alegre, RS (Brazil); Armelin, Elaine, E-mail: elaine.armelin@upc.edu [Departament d' Enginyeria Quimica, ETSEIB, Universitat Politecnica de Catalunya, Av. Diagonal 647, 08028, Barcelona (Spain); Center for Research in Nanoengineering, Universitat Politecnica de Catalunya, Campus Sud, Edifici C' , C/Pasqual i Vila s/n, 08028, Barcelona (Spain)

2011-06-30

Graphical abstract: . Display Omitted Highlights: > Poly(N-methylpyrrole)/poly(styrenesulfonic acid) hollow microstructures has been prepared using gas templates. > The dimensions, abundance and texture of the microstructures have been electrochemically controlled. > Poly(N-methylpyrrole)/poly(styrenesulfonic acid) microstructures act as efficient morphine sensors. - Abstract: Microstructures of poly(N-methylpyrrole) have been generated by direct electrochemical oxidation of N-methylpyrrole with poly(styrenesulfonic acid) in aqueous solution, using a micelle formation mechanism with gas bubble templates. These microstructures present a 'doughnut'-like morphology with diameters ranging from 20 to 100 {mu}m. Other anionic surfactants, such as camphorsulfonic acid and {beta}-naphthalenesulfonic acid, have been also employed, results evidencing that the morphology of the microstructures depends on the nature of the surfactant electrolytes. The dimensions, abundance and texture of the microstructures have been modulated by varying the surfactant molecules, the electrochemical technique, and the distance between the working and counter-electrode. The generated microstructures have been characterized using electrochemical techniques, Raman and infrared spectroscopies, scanning electron microscopy and atomic force microscopy. Hollow microstructures-containing films made of poly(N-methylpyrrole)/poly(styrenesulfonic acid), which present remarkable electroactivity and electrostability, has been proved to interact with morphine molecules. Thus, systems based on this prominent material show a high ability to capture the drug molecules and to retain them for a long period of time.

Chemo-enzymatic modification of poly-N-acetyllactosamine (LacNAc oligomers and N,N-diacetyllactosamine (LacDiNAc based on galactose oxidase treatment

Directory of Open Access Journals (Sweden)

Christiane E. Kupper

2012-05-01

Full Text Available The importance of glycans in biological systems is highlighted by their various functions in physiological and pathological processes. Many glycan epitopes on glycoproteins and glycolipids are based on N-acetyllactosamine units (LacNAc; Galβ1,4GlcNAc and often present on extended poly-LacNAc glycans ([Galβ1,4GlcNAc]n. Poly-LacNAc itself has been identified as a binding motif of galectins, an important class of lectins with functions in immune response and tumorigenesis. Therefore, the synthesis of natural and modified poly-LacNAc glycans is of specific interest for binding studies with galectins as well as for studies of their possible therapeutic applications. We present the oxidation by galactose oxidase and subsequent chemical or enzymatic modification of terminal galactose and N-acetylgalactosamine residues of poly-N-acetyllactosamine (poly-LacNAc oligomers and N,N-diacetyllactosamine (LacDiNAc by galactose oxidase. Product formation starting from different poly-LacNAc oligomers was characterised and optimised regarding formation of the C6-aldo product. Further modification of the aldehyde containing glycans, either by chemical conversion or enzymatic elongation, was established. Base-catalysed β-elimination, coupling of biotin–hydrazide with subsequent reduction to the corresponding hydrazine linkage, and coupling by reductive amination to an amino-functionalised poly-LacNAc oligomer were performed and the products characterised by LC–MS and NMR analysis. Remarkably, elongation of terminally oxidised poly-LacNAc glycans by β3GlcNAc- and β4Gal-transferase was also successful. In this way, a set of novel, modified poly-LacNAc oligomers containing terminally and/or internally modified galactose residues were obtained, which can be used for binding studies and various other applications.

Phase Transition of Poly(acrylic acid-co-N-isopropylacrylamide) Core-shell Nanogels

Science.gov (United States)

Liu, Xiao-bing; Zhou, Jian-feng; Ye, Xiao-dong

2012-08-01

A series of poly(acrylic acid) macromolecular chain transfer agents with different molecular weights were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization and characterized by 1H NMR and gel permeation chromatography. Multiresponsive core-shell nanogels were prepared by dispersion polymerization of N-isopropylacrylamide in water using these poly(potassium acrylate) macro-RAFT agents as the electrosteric stabilizer. The size of the nanogels decreases with the amount of the macro-RAFT agent, indicating that the surface area occupied by per polyelectrolyte group is a critical parameter for stabilizing the nanogels. The volume phase transition and the zeta potentials of the nanogels in aqueous solutions were studied by dynamic light scattering and zetasizer analyzer, respectively.

Phase Diagrams of Smart Copolymers Poly(N-isopropylacrylamide) and Poly(sodium acrylate)

Science.gov (United States)

Di Lorenzo, Maria Laura; Pyda, Marek

2014-01-01

The phase behavior of linear poly(N-isopropylacrylamide) (PNIPA), linear copolymer poly(N-isopropylacrylamide) and poly(sodium acrylate) (PNIPA-SA), and chemically cross-linked PNIPA in water has been determined by temperature modulated differential scanning calorimetry (TM-DSC). Experiments related to linear polymers (PNIPA and PNIPA-SA) indicated nontypical demixing/mixing behavior with a lower critical solution temperature (LCST), which do not correspond to the three classical types of limiting critical behavior. Some similarities and differences are observed in comparison to our literature data using standard TM-DSC for PNIPA/water. Furthermore no influence of composition cross-linked PNIPA/water system on demixing/mixing temperature was observed. PMID:25202728

Phase Diagrams of Smart Copolymers Poly(N-isopropylacrylamide and Poly(sodium acrylate

Directory of Open Access Journals (Sweden)

Iwona Zarzyka

2014-01-01

Full Text Available The phase behavior of linear poly(N-isopropylacrylamide (PNIPA, linear copolymer poly(N-isopropylacrylamide and poly(sodium acrylate (PNIPA-SA, and chemically cross-linked PNIPA in water has been determined by temperature modulated differential scanning calorimetry (TM-DSC. Experiments related to linear polymers (PNIPA and PNIPA-SA indicated nontypical demixing/mixing behavior with a lower critical solution temperature (LCST, which do not correspond to the three classical types of limiting critical behavior. Some similarities and differences are observed in comparison to our literature data using standard TM-DSC for PNIPA/water. Furthermore no influence of composition cross-linked PNIPA/water system on demixing/mixing temperature was observed.

Ophthalmic ester removal in the agar state giant molecule; Kantenjo kobunshi de futarusan esuteru jokyo

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-10-01

Matsubara professors of Tokyo College of Pharmacy developed the technique which simply removed phthalic ester from the solution. The property in which the giant molecule called the poly N isopropyl acrylamide cohered like the agar, when 32 degrees C is exceeded, was utilized, and the phthalic ester of poor solubility is taken in the flocculation stage. It is expected with that it can be utilized for wastewater treatment and solicitation quantity thing analysis in the environment. (translated by NEDO)

Poly(acrylamide) films at the solvent-induced glass transition: Adhesion, tribology, and the influence of crosslinking

NARCIS (Netherlands)

Li, A.; Ramakrishna, S.N.; Kooij, Ernst S.; Espinos-Marzal, R.M.; Spencer, N.D.

2012-01-01

Adhesive and nanotribological properties of end-grafted poly(acrylamide) (PAAm) films with various degrees of crosslinking, and in the presence of solvents over a broad spectrum of quality, were investigated by means of colloidal-probe atomic force microscopy. The solvent consisted of a mixture of

Numancia: relación necrópolis-poblado

Directory of Open Access Journals (Sweden)

Jimeno Martínez, Alfredo

1996-12-01

Full Text Available This paper studies the relationship between the Celtiberian cemetery and the Numancia city sieged by Scipio (133 b.c.. A first part is dedicated to present the location problems of the Celtiberian cemetery during the present century, and the archaeological data of the cemetery are also analyzed. In the second part the stratigraphie questions and the problems to differentiate the city of the II century b.C. are explained. Finally the basis is established for the relationship between the city and the cemetery.Este trabajo estudia la relación entre la necrópolis celtibérica y la Numancia del cerco de Escipión (133 a. C.. En la primera parte se exponen las dificultades para la localización de la necrópolis a lo largo de este siglo y los datos arqueológicos que está aportando su excavación. En la segunda se abordan los problemas estratigráficos y la dificultad de diferenciar la ciudad del 133 a.C. Finalmente se establecen las bases de relación entre necrópolis y poblado.

Synthesis of poly(N-isopropylacrylamide-co-acrylic acid) model compounds for filtration experiments

DEFF Research Database (Denmark)

Hinge, Mogens; Christensen, Morten Lykkegaard; Scales, Peter

2005-01-01

rheometry indicates that the blocks of poly(acrylic acid) are placed on the surface of the microgels. The combination of these three results reveal that the microgels have a core mainly consisting of poly(N-isopropylacrylamide) and a diffuse/cloudy surface consisting mainly of poly(acrylic acid).   The core/shell......  Theoretical development within solid/liquid separation in colloidal systems is largely based on inorganic, low charged and incompressible particles. These do not reflect the properties in biosolid/organic systems. There is therefore a need for a development of colloidal and particles which mimic...

Calorimetric determination of enthalpies for the proton ionization of N,N-bis[2-hydroxyethyl]-2-aminoethanesulfonic acid (BES) and N-tris[hydroxymethyl]methyl-2-aminoethanesulfonic acid (TES) in water-methanol mixtures

International Nuclear Information System (INIS)

Bulos, B.N.; Jumean, F.H.

2004-01-01

The enthalpies of proton ionization of the biochemical buffers N,N-bis[2-hydroxyethyl]-2-aminoethanesulfonic acid (BES) and N-tris[hydroxymethyl]methyl-2-aminoethanesulfonic acid (TES) were obtained in water-methanol mixtures in which the methanol mole fraction (X m ) varied in the range 0-0.36. For both buffers, ionization enthalpy for the first proton (ΔH 1 ) was small in all solvent media. However, upon addition of methanol, ΔH 2 increased steadily from 22.2 to a maximum of 27.2 kJ mol -1 for BES, whereas for TES it varied from 30.0 to 32.4, with a minimum of 28.6 kJ mol -1 at X m =0.123. It is noteworthy that this solvent composition lies within the region of maximum structure enhancement of water by methanol. The results were interpreted in terms of methanol-water interactions

Biodistribution of N-isopropyl-p-iodoamphetamine

International Nuclear Information System (INIS)

Hoshi, Hiroaki; Jinnouchi, Seishi; Watanabe, Katsushi; Ueda, Takashi; Yamaguchi, Tadatoshi

1987-01-01

Biodistribution of N-isopropyl-p-iodoamphetamine (IMP) was experimentally studied for evaluating the usefullness of this radiopharmaceuticals for cerebral perfusion scintigraphy. IMP labeled with radioactive iodine (I-125, I-131), was injected intravenously in awake animals. The activity in the brain of male ddY mice injected 3.7 kBq (0.1 μCi) of I-125 IMP reached 8.0 (%Dose/g) at 10 min. after injection and it was almost constant till 120 min. Activity in the lung and heart was the highest just after injection, and rapidly decreased in the constant level lasting 30 min. to 120 min. Activity in the liver increased slowly and reached peak level at 60 min. Autoradiograms of male ddY mice injected 1.85 MBq (50 μCi) of I-131 IMP showed almost same activity in the spinal cord as the brain. Activities of I-131 IMP in normal brain of Sprague-Dawley rats injected 7.4 MBq (200 μCi) of I-131 IMP were 2.68 - 3.2 (%Dose/g) in the cerebral cortex and 0.59 - 0.66 (%Dose/g) in the white matter at 1 min. after injection. Activities in the cerebral cortex were slightly increased at 60 min. after injection and the activities in the white matter increased markedly at 60 min. and 6 hrs. after injection. The cerebral cortex to white matter ratios were about 5 at 1 min. or 10 min. and about 1 at 60 min. or 6 hrs. after injection. Autoradiograms of normal and ischemic rat brain showed local cerebral blood flow image, but the contrast between the gray matter and the white matter decreased at 60 min. or 6 hrs. Our study on the biodistribution of IMP showed the usefullness of this agent in cerebral perfusion imaging, and may be informative for the interpretation of images. (author)

Methyl and isopropyl N-methylanthranilates attenuate diclofenac- and ethanol-induced gastric lesions in rats.

Science.gov (United States)

Radulović, Niko S; Jovanović, Ivan; Ilić, Ivan R; Randjelović, Pavle J; Stojanović, Nikola M; Miltojević, Ana B

2013-11-19

Two natural alkaloids, methyl (M) and isopropyl (I) N-methylanthranilates, with recently demonstrated significant pharmacological activities, were assayed for their possible overall effect on intact gastric mucosa and their protective properties towards the onset of gastric lesions induced by diclofenac (a non-steroidal anti-inflammatory drug, NSAID) or ethanol. The influence of I and M on gastric mucosa integrity was assessed by oral administration in doses of 200mg/kg. The gastroprotective action of I and M in doses of 50, 100 and 200mg/kg was analyzed in the diclofenac and ethanol-induced gastric lesion models in rats. After the treatment, the stomachs of the animals were analyzed (captured by a digital camera). Ulcer scoring, morphometric and histopathological analyses of the stomachs were done. The oral application of these compounds on their own, even in quite high doses (200mg/kg) did not induce gastric lesions. Both alkaloids exerted a very strong antiulcer activity, even in low doses (50mg/kg), by decreasing the number of lesions caused by the application of either diclofenac or ethanol, eliminating them completely or reducing them to a form of mucosal hyperemia. Their possible mechanism of action was discussed and due to their many positive properties including anxiolytic, antidepressant, antinociceptive, anti-inflammatory and gastroprotective activities, as well as a cheap and simple synthetic route for their preparation, methyl and isopropyl N-methylanthranilates, both alike, might represent a cost effective alternative sought for in the treatment of peptic ulcers and/or new safer NSAIDs for pain management. © 2013.

Electrochemical and Electron Paramagnetic Resonance Study of the Mechanism of Oxidation of Phenazine-di-N-oxide in the Presence of Isopropyl alcohol at Glassy Carbon and Single-Walled Carbon Nanotube Electrodes

International Nuclear Information System (INIS)

Kulakovskaya, S.I.; Kulikov, A.V.; Sviridova, L.N.; Stenina, E.V.

2014-01-01

Graphical abstract: - Highlights: • The mechanism of oxidation of phenazine-di-N-oxide in the presence of isopropyl alcohol was studied. • The results are explained in terms of the E 1 C 1 E 2 C 2 mechanism of the two-stage electrode process. • The total two-electron catalytic oxidation of i-PrOH in the complex with the phenazine-di-N-oxide radical cation was assumed to occur. - Abstract: The mechanism of oxidation of phenazine-di-N-oxide in the presence of isopropyl alcohol was studied by cyclic voltammetry at glassy carbon (GC) and single-walled carbon nanotubes (SWCNT) electrodes in 0.1 M LiClO 4 solutions in acetonitrile. The adsorption of phenazine-di-N-oxide at SWCNT electrode in 0.1 M LiClO 4 solution in acetonitrile was investigated by measurement of the dependence of the differential double layer capacitance of the electrode C on potential E. The effect of isopropyl alcohol on the shape of cyclic voltammograms (CVs) of phenazine-di-N-oxide and the intensity of Electron Paramagnetic Resonance (EPR) signal of its radical cation was investigated. The catalytic currents were recorded at the oxidation of phenazine-di-N-oxide at SWCNT and GC electrodes in the presence of isopropyl alcohol. The results were explained in terms of the E 1 C 1 E 2 C 2 mechanism of two-stage electrode process characterized by catalytic current recorded at the second electrode stage. The overall two-electron catalytic oxidation of isopropyl alcohol in complex with the phenazine-di-N-oxide radical cation was assumed to occur. It was shown that SWCNT electrodes can be used in the electrocatalytic oxidation of organic compounds in the presence of electrochemically generated phenazine-di-N-oxide radical cation

Synthesis and characterization of poly (n-butyl acrylate)-poly (methyl methacrylate) latex interpenetrating polymer networks by radiation-induced seeded emulsion polymerization

Energy Technology Data Exchange (ETDEWEB)

Yu Haibo [Department of Applied Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Peng Jing [Department of Applied Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)], E-mail: jpeng@pku.edu.cn; Zhai Maolin; Li Jiuqiang; Wei Genshuan [Department of Applied Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); Qiao Jinliang [Department of Applied Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China); SINOPEC Beijing Research Institute of Chemical Industry, Beijing 100013 (China)

2007-11-15

A series of latex interpenetrating polymer networks (LIPNs) were prepared via a two-stage emulsion polymerization of methyl methacrylate (MMA) or mixture of MMA and n-butyl acrylate (n-BA) on crosslinked poly(n-butyl acrylate)(PBA) seed latex using {sup 60}Co {gamma}-ray radiation. The particles of resultant latex were produced with diameters between 150 and 250 nm. FTIR spectra identified the formation of crosslinked copolymers of PMMA or P(MMA-co-BA). Dynamic light scattering (DLS) showed that with increasing n-BA concentration in second-stage monomers, the particle size of LIPN increased. Transmission electron microscope(TEM) photographs showed that the morphology of resultant acrylate interpenetrating polymer network (IPN) latex varied from the distinct core-shell structure to homogenous particle structure with the increase of n-BA concentration, and the morphology was mainly controlled by the miscibility between crosslinked PBA seed and second-stage copolymers and polarity of P(MMA-co-BA)copolymers. In addition, differential scanning calorimeter (DSC) measurements indicated the existence of reinforced miscibility between PBA seed and P(MMA-co-BA)copolymer in prepared LIPNs.

Calorimetric determination of enthalpies for the proton ionization of N,N-bis[2-hydroxyethyl]-2-aminoethanesulfonic acid (BES) and N-tris[hydroxymethyl]methyl-2-aminoethanesulfonic acid (TES) in water-methanol mixtures

Energy Technology Data Exchange (ETDEWEB)

Bulos, B.N.; Jumean, F.H

2004-02-19

The enthalpies of proton ionization of the biochemical buffers N,N-bis[2-hydroxyethyl]-2-aminoethanesulfonic acid (BES) and N-tris[hydroxymethyl]methyl-2-aminoethanesulfonic acid (TES) were obtained in water-methanol mixtures in which the methanol mole fraction (X{sub m}) varied in the range 0-0.36. For both buffers, ionization enthalpy for the first proton ({delta}H{sub 1}) was small in all solvent media. However, upon addition of methanol, {delta}H{sub 2} increased steadily from 22.2 to a maximum of 27.2 kJ mol{sup -1} for BES, whereas for TES it varied from 30.0 to 32.4, with a minimum of 28.6 kJ mol{sup -1} at X{sub m}=0.123. It is noteworthy that this solvent composition lies within the region of maximum structure enhancement of water by methanol. The results were interpreted in terms of methanol-water interactions.

Synthesis and characterization of a thermo-sensitive poly( N-methyl acryloylglycine methyl ester) used as a drug release carrier

Science.gov (United States)

Deng, Kui-Lin; Zhong, Hai-Bin; Jiao, Yi-Suo; Fan, Ting; Qiao, Xiao; Zhang, Peng-Fei; Ren, Xiao-Bo

2010-06-01

In this article, poly( N-methyl acryloylglycine methyl ester) (PNMAME) was prepared as a novel thermosensitive material with a lower critical solution temperature (LCST) at around 49.5°C. The chemical structures of the monomer NMAME and PNMAME were characterized by 1H NMR and IR measurements. The LCST was investigated systematically as a function of PNMAME concentration, inorganic salt solution and pH value. The results indicated that LCST of PNMAME was obviously dependent on PNMAME concentration and pH. The LCST was increased with a decrease in pH value and PNMAME concentration. To obtain a thermo-sensitive hydrogel with the phase transition temperature close to human body temperature, the copolymerization was conducted between NMAME and N-acryloylglycine ethyl ester (NAGEE). The release behavior of caffeine was evaluated at different temperatures and contents of cross-linkers ( N, N-methylenebis(acrylamide) (NMBA)). The increase of cross-linker content led to a decrease in the release rate of caffeine due to higher crossing density in the hydrogel network. In addition, a faster release of caffeine from the hydrogel with 3% NMBA at 37°C was found in contrast to that at 18°C.

Synthesis of block copolymers derived from N-trityl-(S)-serine and pyrene end-labeled poly(methyl methacrylate) or poly(N-isopropylacrylamide) via ATRP

International Nuclear Information System (INIS)

Buruiana, Emil C.; Podasca, Viorica; Buruiana, Tinca

2012-01-01

A new monomer bearing N-trityl-L-serine methyl ester in structure, methacryloyloxyethyl carbamoyloxy–N-trityl methyl serine (MTS), was prepared to be further polymerized by atom transfer radical polymerization (ATRP) with pyrene-endcapped poly(methyl methacrylate) (Py–PMMA–Br) or poly(N-isopropylacrylamide) (Py–PNIPA–Br). The resulting block copolymers, poly(methyl methacrylate–block–methacryloyloxyethyl carbamoyloxy–N-trityl methyl serine) (Py–PMMA–b–PMTS) and poly(N-isopropylacrylamide–block–methacryloyloxyethyl carbamoyloxy–N-trityl methyl serine (Py–PNIPA–b–PMTS) were characterized by 1 H ( 13 C) NMR, ultraviolet, FTIR and fluorescence spectroscopy, thermal analysis, differential scanning calorimetry (DSC), atomic force microscopy (AFM), scanning electron microscopy (SEM), and gel permeation chromatography (GPC) measurements. The chemical composition in Py–PMMA–b–PMTS was estimated from the 1 H NMR analysis that indicated a ratio of the repeating units of 46:19 (MMA:MTS). For the Py–PNIPA–b–PMTS the composition rate in the copolymer was 61:25 (NIPA:MTS). Quenching of the pyrene species with N,N-diethylaniline, nitrobenzene, nitrophenol, potassium iodide, p-nitrotoluene and tetracyanoquinodimethane (TCNQ) in DMF solution excited at 348 nm was evidenced, more efficiently being nitrophenol and TCNQ. In this case, the monomer emission at 388–409 nm underwent a significant decrease caused of an electron transfer from the electron-reach photoexcited pyrene molecule to the electron-deficient quenchers. - Highlights: ► Diblock copolymers combine the fluorescence of pyrene–PMMA (PNIPA) with the characteristics of PMTS. ► Such copolymers could be used for nitroderivatives detecting. ► UV/vis and fluorescence measurements give a good correlation for LCST of Py–PNIPA–Br.

Synthesis of block copolymers derived from N-trityl-(S)-serine and pyrene end-labeled poly(methyl methacrylate) or poly(N-isopropylacrylamide) via ATRP

Energy Technology Data Exchange (ETDEWEB)

Buruiana, Emil C., E-mail: emilbur@icmpp.ro [Petru Poni Institute of Macromolecular Chemistry, 41A Gr. Ghica Voda Alley 700487, Iasi (Romania); Podasca, Viorica; Buruiana, Tinca [Petru Poni Institute of Macromolecular Chemistry, 41A Gr. Ghica Voda Alley 700487, Iasi (Romania)

2012-10-15

A new monomer bearing N-trityl-L-serine methyl ester in structure, methacryloyloxyethyl carbamoyloxy-N-trityl methyl serine (MTS), was prepared to be further polymerized by atom transfer radical polymerization (ATRP) with pyrene-endcapped poly(methyl methacrylate) (Py-PMMA-Br) or poly(N-isopropylacrylamide) (Py-PNIPA-Br). The resulting block copolymers, poly(methyl methacrylate-block-methacryloyloxyethyl carbamoyloxy-N-trityl methyl serine) (Py-PMMA-b-PMTS) and poly(N-isopropylacrylamide-block-methacryloyloxyethyl carbamoyloxy-N-trityl methyl serine (Py-PNIPA-b-PMTS) were characterized by {sup 1}H ({sup 13}C) NMR, ultraviolet, FTIR and fluorescence spectroscopy, thermal analysis, differential scanning calorimetry (DSC), atomic force microscopy (AFM), scanning electron microscopy (SEM), and gel permeation chromatography (GPC) measurements. The chemical composition in Py-PMMA-b-PMTS was estimated from the {sup 1}H NMR analysis that indicated a ratio of the repeating units of 46:19 (MMA:MTS). For the Py-PNIPA-b-PMTS the composition rate in the copolymer was 61:25 (NIPA:MTS). Quenching of the pyrene species with N,N-diethylaniline, nitrobenzene, nitrophenol, potassium iodide, p-nitrotoluene and tetracyanoquinodimethane (TCNQ) in DMF solution excited at 348 nm was evidenced, more efficiently being nitrophenol and TCNQ. In this case, the monomer emission at 388-409 nm underwent a significant decrease caused of an electron transfer from the electron-reach photoexcited pyrene molecule to the electron-deficient quenchers. - Highlights: Black-Right-Pointing-Pointer Diblock copolymers combine the fluorescence of pyrene-PMMA (PNIPA) with the characteristics of PMTS. Black-Right-Pointing-Pointer Such copolymers could be used for nitroderivatives detecting. Black-Right-Pointing-Pointer UV/vis and fluorescence measurements give a good correlation for LCST of Py-PNIPA-Br.

Design of poly(vinylidene fluoride)-g-p(hydroxyethyl methacrylate-co-N-isopropylacrylamide) membrane via surface modification for enhanced fouling resistance and release property

International Nuclear Information System (INIS)

Zhao, Guili; Chen, Wei Ning

2017-01-01

Highlights: • PVDF modified membranes were designed by grafting PNIPAAm, PHEMA and their copolymer. • Fouling resistance and release property of membrane were both improved after modification. • Bacterial attachment and detachment were investigated to evaluate fouling release property. • Improvement of the antifouling property was justified by surface property analysis. • The copolymer modified membrane exhibited higher performance to release foulant. - Abstract: Thermo-sensitive polymer poly(N-isopropylacrylamide) (PNIPAAm), hydrophilic polymer poly(hydroxyethyl methacrylate) (PHEMA) and copolymer p(hydroxyethyl methacrylate-co-N-isopropylacrylamide) [P(HEMA-co-NIPAAm)] were synthesized onto poly(vinylidene fluoride) (PVDF) membrane via atom transfer radical polymerization (ATRP) in order to improve not only fouling resistance but also fouling release property. The physicochemical properties of membranes including hydrophilicity, morphology and roughness were examined by contact angle analyzer, scanning electron microscopy (SEM), and atomic force microscopy (AFM), respectively. The antifouling property of membranes was improved remarkably after surface modification according to protein and bacterial adhesion testing, and filtration experiment. Minimum protein adsorption and bacterial adhesion were both obtained on PVDF-g-P(HEMA-co-NIPAAm) membrane, with reduction by 44% and 71% respectively compared to the pristine membrane. The minimum bacterial cells after detachment at 25 °C were observed on the PVDF-g-P(HEMA-co-NIPAAm) membrane with the detachment rate of 77%, indicating high fouling release property. The filtration testing indicated that the copolymer modified membrane exhibited high resistance to protein fouling and the foulant on the surface was released and removed easily by washing, suggesting high fouling release and easy-cleaning capacity. This study provides useful insight in the combined “fouling resistance” and “fouling release�

Design of poly(vinylidene fluoride)-g-p(hydroxyethyl methacrylate-co-N-isopropylacrylamide) membrane via surface modification for enhanced fouling resistance and release property

Energy Technology Data Exchange (ETDEWEB)

Zhao, Guili [Nanyang Environment and Water Research Institute, Interdisciplinary Graduate School, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141 (Singapore); Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, Singapore 637141 (Singapore); School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459 (Singapore); Chen, Wei Ning, E-mail: WNChen@ntu.edu.sg [School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459 (Singapore)

2017-03-15

Highlights: • PVDF modified membranes were designed by grafting PNIPAAm, PHEMA and their copolymer. • Fouling resistance and release property of membrane were both improved after modification. • Bacterial attachment and detachment were investigated to evaluate fouling release property. • Improvement of the antifouling property was justified by surface property analysis. • The copolymer modified membrane exhibited higher performance to release foulant. - Abstract: Thermo-sensitive polymer poly(N-isopropylacrylamide) (PNIPAAm), hydrophilic polymer poly(hydroxyethyl methacrylate) (PHEMA) and copolymer p(hydroxyethyl methacrylate-co-N-isopropylacrylamide) [P(HEMA-co-NIPAAm)] were synthesized onto poly(vinylidene fluoride) (PVDF) membrane via atom transfer radical polymerization (ATRP) in order to improve not only fouling resistance but also fouling release property. The physicochemical properties of membranes including hydrophilicity, morphology and roughness were examined by contact angle analyzer, scanning electron microscopy (SEM), and atomic force microscopy (AFM), respectively. The antifouling property of membranes was improved remarkably after surface modification according to protein and bacterial adhesion testing, and filtration experiment. Minimum protein adsorption and bacterial adhesion were both obtained on PVDF-g-P(HEMA-co-NIPAAm) membrane, with reduction by 44% and 71% respectively compared to the pristine membrane. The minimum bacterial cells after detachment at 25 °C were observed on the PVDF-g-P(HEMA-co-NIPAAm) membrane with the detachment rate of 77%, indicating high fouling release property. The filtration testing indicated that the copolymer modified membrane exhibited high resistance to protein fouling and the foulant on the surface was released and removed easily by washing, suggesting high fouling release and easy-cleaning capacity. This study provides useful insight in the combined “fouling resistance” and “fouling release�

Ferromagnetism in poly(N-perfluorophenylpyrrole)

Energy Technology Data Exchange (ETDEWEB)

Čík, G., E-mail: gabriel.cik@stuba.sk [Department of Environmental Engineering, Faculty of Chemical and Food Technology, Slovak University of Technology, 812 37 Bratislava (Slovakia); Šeršeň, F. [Institute of Chemistry, Faculty of Natural Sciences, Comenius University, 842 15 Bratislava (Slovakia); Dlháň, L. [Department of Inorganic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, 812 37 Bratislava (Slovakia); Zálupský, P. [Department of Organic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, 812 37 Bratislava (Slovakia); Rapta, P. [Department of Physical Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, 812 37 Bratislava (Slovakia); Hrnčariková, K. [Department of Organic Chemistry, Faculty of Chemical and Food Technology, Slovak University of Technology, 812 37 Bratislava (Slovakia); Plecenik, T. [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, 842 48 Bratislava (Slovakia)

2015-10-01

Magnetic properties of the synthesized poly(N-perfluorophenylpyrrole) were studied. The synthesized polymer dissolves in common organic solvents. By the zero-field cooling-field cooling method (ZFC–FC) we found that at low temperatures (T{sub b}<50 K) the synthetic polymer reaches a state with prevailing ferromagnetism. The synthesized polymer retained ferromagnetism even at 300 K. The anomalous magnetic behavior was explained in terms of spin–spin interaction of triplet polarons. As can be seen from the calculated spin density of SOMO and SOMO 1 such a state arise as a consequence of 1-D spin interactions of polarons. Based on the calculated and visualized spin density (SOMO) on the polymer chain such interactions can be explained by the theory of flat-band-ferromagnetism. - Highlights: • We synthesized a new conducting polymer poly(N-perfluorophenylpyrrole). • By the ZFC–FC and EPR methods we measured magnetic properties of the prepared polymer. • We discussed stability and interactions of the polarons in triplet states. • At low temperatures the synthesized polymer reached ferromagnetism.

Synthesis and Characterization of Multiwalled Carbon Nanotubes/Poly(HEMA-co-MMA) by Utilizing Click Chemistry.

Science.gov (United States)

Bach, Long Giang; Cao, Xuan Thang; Islam, Md Rafiqul; Jeong, Yeon Tae; Kim, Jong Su; Lim, Kwon Taek

2016-03-01

The hybrid material consisting of multi walled carbon nanotubes (MWNTs) and poly(2-hydroxyethylmethacrylate-co-methylmethacrylate) [poly(HEMA-co-MMA)] was synthesized by a combination of RAFT and Click chemistry. In the primary stage, the copolymer poly(HEMA-co-MMA) was prepared by applying RAFT technique. Alkynyl side groups were incorporated onto the poly(HEMA-co-MMA) backbone by esterification reaction. Then, MWNTs-N3 was prepared by treating MWNTs with 4-azidobutylamine. The click coupling reaction between azide-functionalized MWNTs (MWNTs-N3) and the alkyne-functionalized random copolymer ((HEMA-co-MMA)-Alkyne) with the Cu(I)-catalyzed [3+2] Huisgen cycloaddition afforded the hybrid compound. The structure and properties of poly(MMA-co-HEMA)-g-MWNTs were investigated by FT-IR, EDX and TGA measurements. The copolymer brushes were observed to be immobilized onto the functionalized MWNTs by SEM and TEM analysis.

Synthesis of amphiphilic poly(ε-caprolactone)-b-poly( N-vinylcaprolactam) block copolymers via the combination of RAFT polymerization and click chemistry

International Nuclear Information System (INIS)

Assis, Paulo Henrique; Aguiar, Graziele Aparecida de Jesus; Moraes, Rodolfo Minto de; Medeiros, Simone de Fatima; Santos, Amilton Martins

2016-01-01

Full text: In recent years, well-defined block copolymers composed of a hydrophilic and hydrophobic segments have gained much interest as drug carriers, because of their enhanced solubility and sustained release of the drug in controlled delivery systems [1]. The development of strategies to obtain block copolymers has attracted considerable attention, due to the possibility to combine characteristic properties of the homopolymers. A wide variety of well-defined block copolymers have been successfully synthesized by combining the efficiency and selectivity of click chemistry with the powerful RAFT polymerization mechanism. In the present work, well-defined amphiphilic, biocompatible, partially biodegradable, and thermosensitive poly(ε-caprolactone)-b-poly(N-vinylcaprolactam) (PCL-b-PNVCL) block copolymers were synthesized by combining ring opening polymerization (ROP), reversible addition-fragmentation chain transfer (RAFT) polymerization and subsequent click chemistry reaction. Alkyne-terminated poly(ε-caprolactone) (alkyne-PCL) was obtained by the ring opening polymerization of ε-caprolactone (ε-CL) using propargyl alcohol as initiator and stannous-2-ethylhexanoate [Sn(Oct) 2 ] as catalyst. The azide end-capped-poly(N-vinylcaprolactam) (PNVCL-N 3 ) was synthesized by reversible addition-fragmentation chain transfer/macromolecular design via interchange of xanthates (RAFT/MADIX) polymerization of the N-vinylcaprolactam (NVCL) mediated by a novel chain transfer agent comprising an azide function , 2-azidoethyl[(ethoxycarbonothioyl)thio](phenyl)acetate. These functionalized homopolymers, alkyne-PCL and PNVCL-N 3 , were coupled by the 1,3 dipolar cycloaddition reaction in order to obtain the corresponding block copolymers. These (co)polymers were characterized by FTIR, 1 H NMR and GPC measurements. Reference: 1. RAMESH, K., SINGH, S., MITRA, K., CHATTOPADHYAY, D., MISRA, N., & RAY, B. (2015). Colloid and Polymer Science, 1-9. (author)

Isobaric (vapour + liquid + liquid) equilibrium data for (di-n-propyl ether + n-propyl alcohol + water) and (diisopropyl ether + isopropyl alcohol + water) systems at 100 kPa

International Nuclear Information System (INIS)

Lladosa, Estela; Monton, Juan B.; Burguet, MaCruz; Torre, Javier de la

2008-01-01

Isobaric (vapour + liquid + liquid) equilibria were measured for the (di-n-propyl ether + n-propyl alcohol + water) and (diisopropyl ether + isopropyl alcohol + water) system at 100 kPa. The apparatus used for the determination of (vapour + liquid + liquid) equilibrium data was an all-glass dynamic recirculating still with an ultrasonic homogenizer couple to the boiling flask. The experimental data demonstrated the existence of a heterogeneous ternary azeotrope for both ternary systems. The (vapour + liquid + liquid) equilibria data were found to be thermodynamically consistent for both systems. The experimental data were compared with the estimation using UNIQUAC and NRTL models and the prediction of UNIFAC model

Experimental study on liver accumulation of N-isopropyl-p-iodoamphetamine

Energy Technology Data Exchange (ETDEWEB)

Kosuda, Shigeru (Tokyo Metropolitan Komagome Hospital (Japan)); Kawahara, Shunji; Ishibashi, Akihiko; Tamura, Kohei; Kubo, Atsushi; Hashimoto, Shozo

1990-06-01

In order to clarify the mechanism of N-isopropyl-p-iodoamphetamine (IMP) liver accumulation, liver dynamic study by the portal injection of {sup 123}I-IMP and liver microautoradiography by {sup 125}I-IMP were performed using 5, 2 male rats, respectively. The initial uptake of {sup 123}I-IMP in the liver was very high and thereafter {sup 123}I-IMP showed relatively rapid wash-out (count ratio of lung to liver at 10 min after the injection was 0.12, 0.15). On the other hand, the addition of 5 mg, 8 mg ketamine hydrochloride decreased the initial {sup 123}I-IMP liver uptake and its lung accumulation was noted immediately after the injection (count ratio of lung to liver at 10 min was 0.20). Microautoradiography of the liver using {sup 125}I-IMP showed grain density in the central vein and sinusoids, but not in the liver parenchymal cell. These results suggest that non-specific amine receptor (binding site) may exist in the endothelial cell in the central vein, although the number of experimental rats in this series was small for conclusion. (author).

Facile Synthesis of N-Tosyl Aza-Baylis-Hillman Adducts of Acrylamide via a Pd-Catalyzed Hydration of Nitrile to Amide

International Nuclear Information System (INIS)

Kim, Eun Sun; Kim, Yu Mi; Kim, Jae Nyoung

2010-01-01

We developed an efficient palladium-catalyzed two-step protocol for the synthesis of N-tosyl aza-Baylis-Hillman adducts of acrylamide. The method involved the preparation of the corresponding Baylis-Hillman adducts of acrylonitrile and the following Pd-catalyzed hydration of nitrile with acetaldoxime. The Baylis-Hillman reaction, which involves the coupling of activated vinyl compounds with electrophiles under the catalytic influence of a tertiary amine, gives rise to adducts, so called Baylis-Hillman adducts, with a new stereocenter and has proven to be a very useful carbon-carbon bond-forming method in the synthesis of highly functionalized molecules. As the activated vinyl compounds, various compounds have been used in the Baylis-Hillman reaction including acrylates, acrylonitrile, vinyl ketones, vinyl sulfones and acrylamides. However, among the activated vinyl compounds acrylamide has not been used much for the synthesis of the corresponding Baylis-Hillman adducts due to its sluggish reactivity

Colour vision and light sensitivity in tunnel workers previously exposed to acrylamide and N-methylolacrylamide containing grouting agents.

Science.gov (United States)

Goffeng, Lars Ole; Kjuus, Helge; Heier, Mona Skard; Alvestrand, Monica; Ulvestad, Bente; Skaug, Vidar

2008-01-01

The aim of the study was to examine possible persisting visual system effects in tunnel workers previously exposed to acrylamide and N-methylolacrylamide during grouting work. Visual field light sensitivity threshold and colour vision has been examined among 44 tunnel workers 2-10 years after exposure to acrylamide and N-methylolacrylamide containing grouting agents. Forty-four tunnel workers not involved in grouting operations served as control group. Information on exposure and background variables was obtained for all participants from a questionnaire. Visual light sensitivity threshold was measured using Humphrey Visual Field Static Perimeter 740, program 30-2 Fastpack, with red stimuli on white background, and colour vision, using Lanthony D-15 Desaturated Color test. Based on D-15d test results, colour confusion index (CCI), and a severity index (C-index) was calculated. The exposed group had a significantly higher threshold for detecting single stimuli in all parts of the inner 30 degrees of the visual field compared to the control group. The foveal threshold group difference was 1.4 dB (p=0.002) (mean value, both eyes). On the Lanthony 15 Hue Desaturated test, the exposed subjects made more errors in sorting blue colours, and a statistically significant increase in C-index was observed. Surrogate measures for duration and intensity of exposure gave no further improvement of the model. The results indicate slightly reduced light sensitivity and reduced colour discrimination among the exposed subjects compared to the controls. The findings may be due to previous exposure to acrylamide containing grouts among the tunnel workers.

Cerebral dynamics of N-isopropyl-(123I)p-iodoamphetamine

International Nuclear Information System (INIS)

Creutzig, H.; Schober, O.; Gielow, P.; Friedrich, R.; Becker, H.; Dietz, H.; Hundeshagen, H.

1986-01-01

Temporal changes in the distribution of N-isopropyl-(123I)p-iodoamphetamine (IMP) within the brain are measured with serial tomographic imaging. In the cerebellum there is a decrease in activity of 42% from the early [15-45 min postinjection (p.i.)] to the late (210-240 min p.i.) scan, while in the cortex the decrease is 18%, and in the basal ganglia there is no decrease within this time. In brain tumors there was no IMP uptake in the early as well as in the late scans, regardless of tumor type, perfusion rate, or blood-brain barrier dysfunction. In 11 of 43 patients with a cerebral infarction a real increase of 123I activity (mean +21%) was seen in the late images. This ''filling in'' phenomena might be useful in selecting patients for bypass surgery. In these patients the diaschisis cerebelli, seen in the early scans, disappeared in the late images. The regional distribution of IMP changes with time; spatial ratios might be blurred by temporal changes. High-flow areas such as visio-auditory centers can be delineated clearly after stimulation in fast early scans; in these areas the pharmacokinetics of 123I are different from other cortex regions. To get the full information from the IMP brain uptake, both spatial and temporal variation must be measured

N-isopropyl I-123 p-iodoamphetamine (IMP) brain SPECT in dementia

International Nuclear Information System (INIS)

Momose, Toshimitsu; Kosaka, Noboru; Nishikawa, Junichi; Yoshikawa, Kohki; Ohtake, Tohru; Watanabe, Toshiaki; Iwata, Makoto; Shimizu, Teruo; Iio, Masahiro

1988-01-01

Six patients of Alzheimer's disease (AD), two patients of Pick disease (PD) and two patients of Creutzfeldt-Jakob disease (CJD) were studied with N-Isopropyl I-123 p-Iodoamphetamine (IMP) with SPECT. The pattern of IMP uptake in these demented groups were compared with that in five agematched normal controls and correlated with MRI and XCT. In all AD cases, SPECT revealed focal reduction of IMP uptake in frontal (6/6), parietal (6/6) and temporal (6/6) cortex, although MRI and XCT were normal. In both PD case, SPECT showed focal reduction of IMP uptake in frontal (1/2) and temporal (2/2) cortex with moderate labor atrophy on MRI and XCT. In both CJD case, SPECT showed diffuse reduction of IMP uptake in cerebral cortex in spite of no abnormality on MRI and XCT. These findings suggest that SPECT can detect earlier diseased process of AD and CJD than MRI or XCT and that SPECT may be helpful for the differential diagnosis of non-vascular dementia. (author)

N-isopropyl I-123 p-iodoamphetamine (IMP) brain SPECT in dementia

Energy Technology Data Exchange (ETDEWEB)

Momose, Toshimitsu; Kosaka, Noboru; Nishikawa, Junichi; Yoshikawa, Kohki; Ohtake, Tohru; Watanabe, Toshiaki; Iwata, Makoto; Shimizu, Teruo; Iio, Masahiro

1988-12-01

Six patients of Alzheimer's disease (AD), two patients of Pick disease (PD) and two patients of Creutzfeldt-Jakob disease (CJD) were studied with N-Isopropyl I-123 p-Iodoamphetamine (IMP) with SPECT. The pattern of IMP uptake in these demented groups were compared with that in five agematched normal controls and correlated with MRI and XCT. In all AD cases, SPECT revealed focal reduction of IMP uptake in frontal (6/6), parietal (6/6) and temporal (6/6) cortex, although MRI and XCT were normal. In both PD case, SPECT showed focal reduction of IMP uptake in frontal (1/2) and temporal (2/2) cortex with moderate labor atrophy on MRI and XCT. In both CJD case, SPECT showed diffuse reduction of IMP uptake in cerebral cortex in spite of no abnormality on MRI and XCT. These findings suggest that SPECT can detect earlier diseased process of AD and CJD than MRI or XCT and that SPECT may be helpful for the differential diagnosis of non-vascular dementia.

Synthesis and characterization of novel N-substituted poly aniline by Triton X-100

International Nuclear Information System (INIS)

Arsalani, N.; Khavei, M.; Entezami, A. A.

2003-01-01

A new N-substituted poly aniline is synthesized by insertion of polyether chain in the form of Triton X-100 onto the poly aniline backbone. In the preparation method, firstly the emeraldine base poly aniline was reacted with Na H to produce the N-anionic doped poly aniline and then contacted with chlorinated Triton X-100. The prepared N-substituted poly aniline was characterized by UV-vis, FTIR, 1 H NMR spectroscopy techniques and elemental analysis. The physical properties of synthesized polymer such as electrical conductivity, thermal and electro activity properties were also studied. The prepared polymer has good solubility in common organic solvents such as T HF and chloroform

Regional cerebral blood flow in Parkinson's disease measured with N-isopropyl-p-[123I]iodoamphetamine (IMP) SPECT

International Nuclear Information System (INIS)

Odano, Ikuo; Nishihara, Mamiko; Hayashi, Hiroko; Higuchi, Shoichi; Sakai, Kunio; Ishikawa, Atsushi; Ibayashi, Katsuhiko.

1992-01-01

N-isopropyl-p-[ 123 I]iodoamphetamine (IMP) SPECT studies were performed on 21 patients (13 females; 45-73 yrs) with idiopathic Parkinson's disease (PD) and 10 age-matched normal controls (39-69 yrs). Regional cerebral blood flow (rCBF) was quantitatively measured by the arterial blood sampling method. When compared with normal controls, global CBF, and rCBF in the frontal cortex and in the basal ganglia were reduced 22.1% (p 123 I-IMP SPECT imaging is useful for evaluation and follow-up of patients with PD. (author)

Nicotine-selective radiation-induced poly(acrylamide/maleic acid) hydrogels

International Nuclear Information System (INIS)

Saraydin, D.; Karadag, E.; Caldiran, Y.; Gueven, O.

2001-01-01

Nicotine-selective poly(acrylamide/maleic acid) (AAm/MA) hydrogels prepared by γ-irradiation were used in experiments on swelling, diffusion, and interactions of the pharmaceuticals nicotine, nicotinic acid, nicotinamide, and nikethamide. For AAm/MA hydrogel containing 60 mg maleic acid and irradiated at 5.2 kGy, the studies indicated that swelling increased in the following order; nicotine>nicotinamide>nikethamide>nicotinic acid>water. Diffusions of water and the pharmaceuticals within the hydrogels were found to be non-Fickian in character. AAm/MA hydrogel sorbed only nicotine and did not sorb nicotinamide, nikethamide and nicotinic acid in the binding experiments. S-type adsorption in Giles's classification system was observed. Some binding and thermodynamic parameters for AAm/MA hydrogel-nicotine system were calculated using the Scatchard method. The values of adsorption heat and free energy of this system were found to be negative whereas adsorption entropy was found to be positive. (author)

Grafting of acrylamide onto synthetic co polyamide by gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Hamoud, M R; Qamhieyh, E A [Chemistry Dept., College of Ibn Al-Haitham Baghdad university-Adhamiyah-Baghdad- (Iraq)

1995-10-01

Grafted copolymer was prepared by using gamma irradiation to graft acrylamide onto polymeric molecule prepared by interfacial condensation between two diamine molecules like 1,2 diamino propane and 1,6 diamino-hexane in aqueous layer with sebacoyl chloride in organic layer. The resulted co polyamide was grafted with acrylamide using gamma irradiation. The optimum conditions of grafting reaction were found, also various factors such as the effect of solvents, redox systems and the role water on the radiochemical grafting were studied. Many techniques were used in the characterization of the copolymer before and after grafting. 8 figs.,.

Catena-poly[[bis(1H-benzotriazole-kappaN3)cobalt(II)]-di-mu-tricyanomethanido-kappa2N:N'] and catena-poly[[bis(3,5-dimethyl-1H-pyrazole-kappaN2)manganese(II)]-di-mu-tricyanomethanido-kappa2N:N'].

Science.gov (United States)

Shao, Ze-Huai; Luo, Jun; Cai, Rui-Fang; Zhou, Xi-Geng; Weng, Lin-Hong; Chen, Zhen-Xia

2004-06-01

Two new one-dimensional coordination polymers, viz. the title compounds, [Co[C(CN)(3)](2)(C(6)H(5)N(3))(2)](n), (I), and [Mn[C(CN)(3)](2)(C(5)H(8)N(2))(2)](n), (II), have been synthesized and characterized by X-ray diffraction. Both complexes consist of linear chains with double 1,5-tricyanomethanide bridges between neighbouring divalent metal ions. The Co and Mn atoms are located on centres of inversion. In (I), the coordination environment of the Co(II) atom is that of an elongated octahedron. The Co(II) atom is coordinated in the equatorial plane by four nitrile N atoms of four bridging tricyanomethanide ions, with Co-N distances of 2.106 (2) and 2.110 (2) A, and in the apical positions by two N atoms from the benzotriazole ligands, with a Co-N distance of 2.149 (2) A. The [Co[C(CN)(3)](2)(C(6)H(5)N(3))(2)] units form infinite chains extending along the a axis. These chains are crosslinked via a hydrogen bond between the uncoordinated nitrile N atom of a tricyanomethanide anion and the H atom on the uncoordinated N atom of a benzotriazole ligand from an adjacent chain, thus forming a three-dimensional network structure. In (II), the Mn(II) atom also adopts a slightly distorted octahedral geometry, with four nitrile N atoms of tricyanomethanide ligands [Mn-N = 2.226 (2) and 2.227 (2) A] in equatorial positions and two N atoms of the monodentate 3,5-dimethylpyrazole ligands [Mn-N = 2.231 (2) A] in the axial sites. In (II), one-dimensional polymeric chains extending along the b axis are formed, with tricyanomethanide anions acting as bidentate bridging ligands. A hydrogen bond between the uncoordinated nitrile N atom of the tricyanomethanide ligand and the H atom on the uncoordinated N atom of a 3,5-dimethylpyrazole group from a neighbouring chain links the molecule into a two-dimensional layered structure.

Quantification of brain perfusion SPECT with N-isopropyl-p-iodoamphetamine using noninvasive microsphere method. Estimation of arterial input by dynamic imaging

International Nuclear Information System (INIS)

Yonekura, Yoshiharu; Sugihara, Hideki; Taniguchi, Yoshimitsu; Aoki, Etsuo; Furuichi, Kenji; Miyazaki, Yoshiharu.

1997-01-01

We have developed a noninvasive method to quantify brain perfusion SPECT with 123 I-N-isopropyl-p-iodoamphetamine (IMP) using serial dynamic planar imaging of the initial transit phase. The method is based on the microsphere model, but does not require arterial sampling. Serial dynamic planar imaging was performed for 6 min after the bolus injection of IMP (167 MBq in 1.5 ml), followed by additional planar imaging at 20 min and SPECT scan thereafter. The total arterial input to the brain during the initial 5 min after injection was estimated by the injected dose, with the correction of the lung retention, divided by cardiac output (CO). CO was estimated from the initial transit of IMP in the right heart. Cardiac output index (COI), obtained from the integral of the first transit of IMP in the right heart divided by the injected dose, was calibrated by CO measured by Doppler ultrasonography. Regional cerebral blood flow (rCBF) obtained by this method in normal subjects was acceptable. However, the results may be influenced by the injection technique, and careful attention should be considered for clinical application of this method. (author)

Synthesis and Thermosensitive Behavior of Polyacrylamide Copolymers and Their Applications in Smart Textiles

Directory of Open Access Journals (Sweden)

Tao Chen

2015-05-01

Full Text Available We tuned the lower critical solution temperature (LCST of amphiphilic poly(N-isopropylacrylamide (PNIPAAm via copolymerization with a hydrophilic comonomer of N-hydroxymethyl acrylamide (NHMAAm. A series of copolymers P(NIPAAm-co-NHMAAm were synthesized by atom transfer radical polymerization (ATRP using CuBr/(N,N,N',N',N''-Pentamethyldiethylenetriamine (PMDETA as a catalyst system and 2-bromo ethyl isobutyrate (EBiB as an initiator. The copolymers were well characterized by Fourier transform infrared spectroscopy (FT-IR, 1H Nuclear magnetic resonance (NMR, and Thermogravimetric analysis (TGA. The copolymers followed a simple rule in their thermosensitive behaviors and have a linear increase in the LCST as a function of NHMAAm mol%. The thermosensitive properties of the copolymer films were investigated and demonstrated hydrophilic-hydrophobic transitions. Finally, the copolymer was grafted onto cotton fabrics using citric acid (CA as a crosslinking agent and sodium hypophosphite (SHP as a catalyst following a two dipping, two padding process. The large number of hydroxyl groups in the copolymer makes grafting convenient and firm. The grafted cotton fabrics show obvious thermosensitive behaviors. The results demonstrate that the cotton fabrics become more hydrophobic when the temperature is higher than the LCST. This study presents a valuable route towards temperature-responsive smart textiles and their potential applications.

Thermodynamic Interactions between Polystyrene and Long-Chain Poly(n-Alkyl Acrylates) Derived from Plant Oils.

Science.gov (United States)

Wang, Shu; Robertson, Megan L

2015-06-10

Vegetable oils and their fatty acids are promising sources for the derivation of polymers. Long-chain poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) are readily derived from fatty acids through conversion of the carboxylic acid end-group to an acrylate or methacrylate group. The resulting polymers contain long alkyl side-chains with around 10-22 carbon atoms. Regardless of the monomer source, the presence of alkyl side-chains in poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) provides a convenient mechanism for tuning their physical properties. The development of structured multicomponent materials, including block copolymers and blends, containing poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) requires knowledge of the thermodynamic interactions governing their self-assembly, typically described by the Flory-Huggins interaction parameter χ. We have investigated the χ parameter between polystyrene and long-chain poly(n-alkyl acrylate) homopolymers and copolymers: specifically we have included poly(stearyl acrylate), poly(lauryl acrylate), and their random copolymers. Lauryl and stearyl acrylate were chosen as model alkyl acrylates derived from vegetable oils and have alkyl side-chain lengths of 12 and 18 carbon atoms, respectively. Polystyrene is included in this study as a model petroleum-sourced polymer, which has wide applicability in commercially relevant multicomponent polymeric materials. Two independent methods were employed to measure the χ parameter: cloud point measurements on binary blends and characterization of the order-disorder transition of triblock copolymers, which were in relatively good agreement with one another. The χ parameter was found to be independent of the alkyl side-chain length (n) for large values of n (i.e., n > 10). This behavior is in stark contrast to the n-dependence of the χ parameter predicted from solubility parameter theory. Our study complements prior work investigating the interactions between

Temperature Induced Solubility Transitions of Various Poly(2-oxazolines in Ethanol-Water Solvent Mixtures

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Hanneke M. L. Lambermont-Thijs

2010-08-01

Full Text Available The solution behavior of a series of poly(2-oxazolines with different side chains, namely methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, pentyl, hexyl, heptyl, octyl, nonyl, phenyl and benzyl, are reported in ethanol-water solvent mixtures based on turbidimetry investigations. The LCST transitions of poly(2-oxazolines with propyl side chains and the UCST transitions of the poly(2-oxazolines with more hydrophobic side chains are discussed in relation to the ethanol-water solvent composition and structure. The poly(2-alkyl-2-oxazolines with side chains longer than propyl only dissolved during the first heating run, which is discussed and correlated to the melting transition of the polymers.

N-isopropyl-p-[123I]iodoamphetamine SPECT in MELAS syndrome: Comparison with CT and MR imaging

International Nuclear Information System (INIS)

Satoh, M.; Ishikawa, N.; Yoshizawa, T.; Takeda, T.; Akisada, M.

1991-01-01

Regional cerebral perfusion was studied in three patients with the mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome, using single photon emission computed tomography (SPECT) with N-isopropyl-p-[123I]iodoamphetamine (IMP). Accumulation of the tracer was relatively decreased in the parietooccipital regions and also in the frontotemporal regions after stroke-like episodes. However, quantitative regional cerebral blood flow (rCBF) measurement showed that rCBF was relatively well preserved even at these sites, and a hyperemic state was observed at the sites of normal accumulation. IMP SPECT may be useful in the diagnosis and assessment of the progress of the MELAS syndrome

The study on grafting comonomer of n-butyl acrylate and styrene onto poly(ethylene terephthalate) film by gamma-ray induced graft copolymerization

Energy Technology Data Exchange (ETDEWEB)

Ping Xiang; Wang Mozhen [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China); Ge Xuewu, E-mail: xwge@ustc.edu.c [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026 (China)

2010-09-15

Poly(ethylene terephthalate) (PET) film was successfully grafted with n-butyl acrylate and styrene comonomer through gamma-ray induced graft copolymerization. The degree of grafting (DG) and the composition of grafted side chain were characterized by {sup 1}H NMR. It was found that St can inhibit the homopolymerization of BA effectively and increase the DG when the concentration of comonomer mixture is kept constant. The proportion of St to BA in grafted side chain has a positive dependence on the feed ratio of St, which ultimately approaches the feed ratio. The thermal properties of poly(ethylene terephthalate)-graft-poly(n-butyl acrylate-co-styrene) (PET-g-P(BA-co-St)) films were investigated by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). The T{sub g} of PET decreases with the DG, indicating that the grafted P(BA-co-St) copolymer has good compatibility with PET backbone.

Crystal structure of 4-tert-butyl-2-{2-[N-(3,3-dimethyl-2-oxobutyl-N-isopropylcarbamoyl]phenyl}-1-isopropyl-1H-imidazol-3-ium perchlorate

Directory of Open Access Journals (Sweden)

Olga V. Hordiyenko

2015-02-01

Full Text Available In the title salt, C26H40N3O2+·ClO4−, the positive charge of the organic cation is delocalized between the two N atoms of the imidazole ring. The C...;N bond distances are 1.338 (2 and 1.327 (3 Å. The substituents on the benzene ring are rotated almost orthogonal with respect to this ring due to the presence of the bulky isopropyl substituents. The dihedral angle between the benzene and imidazole rings is 75.15 (12°. Three of the O atoms of the anion are disordered over two sets of sites due to rotation around one of the O—Cl bonds. The ratio of the refined occupancies is 0.591 (14:0.409 (14. In the crystal, the cation and perchlorate anion are bound by an N—H...O hydrogen bond. In addition, the cation–anion pairs are linked into layers parallel to (001 by multiple weak C—H...O hydrogen bonds.

Structure of poly(di-n-hexylsilane) in nanoporous materials

International Nuclear Information System (INIS)

Korotkova, I.; Sakhno, T.; Drobit'ko, I.; Sakhno, Yu.; Ostapenko, N.

2010-01-01

Graphical abstract: On the basis of theoretical calculations using TD/CEP-31G method we found and interpreted the complexation mechanism of poly(di-n-hexylsilane) incorporated in nanoporous materials. - Abstract: In this work the effects of solvent polarity and conformation changing on the electronic characteristics of poly(di-n-hexylsilane) incorporated in the nanoporous materials are calculated. The dependence of energy levels of electronic-excited states of investigated compounds is analyzed as a function of the Si-Si-Si-Si twist angle and length of Si-Si and Si-C bonds. The possibility of complex formation between silicon atom of polymer and oxygen ions of nanoporous materials is shown.

Analysis of acrylamide in coffee and dietary exposure to acrylamide from coffee

DEFF Research Database (Denmark)

Granby, Kit; Fagt, Sisse

2004-01-01

An analytical method for analysing acrylamide in coffee was validated. The analysis of prepared coffee includes a comprehensive clean-up using multimode solid-phase extraction (SPE) by automatic SPE equipment and detection by liquid chromatography tandem mass spectrometry using electrospray...... in the positive mode. The recoveries of acrylamide in ready-to-drink coffee spiked with 5 and 10 mug l(-1) were 96 +/- 14% and 100 +/- 8%, respectively. Within laboratory reproducibility for the same spiking levels were 14% and 9%, respectively. Coffee samples (n = 25) prepared twice by coffee machines and twice...... by a French Press Cafetiere coffee maker contained 8 +/- 3 mug l(-1) and 9 +/- 3 mug l(-1) acrylamide. Five ready-to-drink instant coffee prepared twice contained 8 +/- 2 mug l(-1). Hence, the results do not show significant differences in the acrylamide contents in ready-to-drink coffee prepared by coffee...

Stability of poly(N-isopropylacrylamide-co-acrylic acid polymer microgels under various conditions of temperature, pH and salt concentration

Directory of Open Access Journals (Sweden)

Zahoor H. Farooqi

2017-03-01

Full Text Available This research article describes the colloidal stability of poly(N-isopropylacrylamide-co-acrylic acid [P(NIPAM-co-AAc] polymer microgels with different acrylic acid contents in aqueous medium under various conditions of temperature, pH and sodium chloride concentrations. Three samples of multi-responsive P(NIPAM-co-AAc polymer microgels were synthesized using different amounts of acrylic acid by free radical emulsion polymerization. Dynamic laser light scattering was used to investigate the responsive behavior and stability of the prepared microgels under various conditions of pH, temperature and ionic strength. The microgels were found to be stable at all pH values above the pKa value of acrylic acid moiety in the temperature range from 15 to 60 °C in the presence and absence of sodium chloride. Increase in temperature, salt concentration and decrease in pH causes aggregation and decreases the stability of microgels due to the decrease in hydrophilicity.

Study of poly(N,N-dimethylacrylamide)/CdS nanocomposite organic/inorganic gels.

Science.gov (United States)

Bekiari, Vlasoula; Pagonis, Konstantinos; Bokias, Georgios; Lianos, Panagiotis

2004-09-14

CdS nanoparticles have been synthesized and stabilized in poly(N,N-dimethylacrylamide) hydrogels. The properties of the composite material have been characterized by UV-vis spectroscopy, scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and steady-state and time-resolved luminescence spectroscopy. This material can be obtained in three different states: swollen, shrunk, and freeze-dried. The swollen and the freeze-dried states correspond to a nanocomposite organic/inorganic (wet or dry) gel containing CdS nanoparticles of approximately 50 nm diameter while the shrunk state is a two-phase system containing CdS crystals, which precipitate forming interesting geometrical shapes.

Preparation of hydrophilic monolithic capillary column by in situ photo-polymerization of N-vinyl-2-pyrrolidinone and acrylamide for highly selective and sensitive enrichment of N-linked glycopeptides.

Science.gov (United States)

Jiang, Hao; Yuan, Huiming; Qu, Yanyan; Liang, Yu; Jiang, Bo; Wu, Qi; Deng, Nan; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

2016-01-01

In this study, a novel kind of amide functionalized hydrophilic monolith was synthesized by the in situ photo-polymerization of N-vinyl-2-pyrrolidinone (NVP), acrylamide (AM), and N, N'-methylenebisacrylamide (MBA) in a UV transparent capillary, and successfully applied for hydrophilic interaction chromatography (HILIC) based enrichment of N-linked glycopeptides. With 2 μg of the tryptic digests of IgG as the sample, after enrichment, 18 glycopeptides could be identified by MALDI-TOF/TOF MS analysis. Furthermore, with the mixture of BSA and IgG digests (10,000:1, m/m) as the sample, 6 N-linked glycopeptides were unambiguously identified after enrichment, indicating the high selectivity and good specificity of such material. Moreover, such a monolithic capillary column was also applied for the N-glycosylation sites profiling of 6 μg protein digests from HeLa cells and 1 μL human serum. In total, 530 and 262 unique N-glycosylated peptides were identified, respectively, corresponding to 282 and 124N-glycoproteins, demonstrating its great potential for the large scale glycoproteomics analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterization of temperature and pH-responsive poly-N-isopropylacrylamide-co-polymer nanoparticles for the release of antimicrobials

International Nuclear Information System (INIS)

Hill, Laura E; Gomes, Carmen L

2014-01-01

Chitosan and alginate are both pH-responsive biopolymers extracted from crustacean exoskeletons and brown algae, respectively. Poly-N-isopropylacrylamide (PNIPAAM) is a hydrogel that becomes hydrophobic at a lower-critical solution temperature. This study sought to combine pH- and temperature-responsive polymers via crosslinking, in order to create a dual-stimuli responsive polymer for hydrophobic antimicrobial compounds delivery, improving their antimicrobial effects. Cinnamon bark extract (CBE) was used as a model for hydrophobic antimicrobial. Two co-polymers were synthesized to create two nanoparticles types: chitosan-co-PNIPAAM and alginate-co-PNIPAAM. Nanoparticles were formed from the resulting co-polymers using a self-assembly top-down process followed by glutaraldehyde or calcium chloride crosslinking. These nanoparticles were then used as controlled delivery vehicles for CBE, whose rapid release could be triggered by specific external stimuli. For the same pH and temperature conditions, the chitosan-co-PNIPAAM nanoparticles were significantly more potent bacterial inhibitors against both pathogens and also exhibited a faster CBE release over time as well as slightly higher entrapment efficiency. The alginate-co-PNIPAAM nanoparticles were significantly smaller and exhibited a slow, gradual release over a long time period. Although both nanoparticles were able to effectively inhibit pathogen growth at lower (P < 0.05) concentration than free CBE, the chitosan-co-PNIPAAM nanoparticles were more effective in delivering a natural antimicrobial with controlled release against foodborne pathogens. (paper)

Study of complex formation of cobalt (II) and cobalt (III) in acrylamide aqueous solutions and in the phase of acrylamide hydrogel

International Nuclear Information System (INIS)

Ismailova, M.M.; Egorova, L.A.; Khamidov, B.O.

1993-01-01

Present article is devoted to study of complex formation of cobalt (II) and cobalt (III) in acrylamide aqueous solutions and in the phase of acrylamide hydrogel. The condition of cobalt in various rate of oxidation in acrylamide aqueous solutions was studied. The concentration conditions of stability of system Co(II)-Co(III) were defined. The composition of coordination compounds of cobalt (II) and cobalt (III) in acrylamide aqueous solutions and in the phase of acrylamide hydrogel was determined.

Thermo-responsive, UV-active poly(phenyl acrylate-b-poly(diethyl acrylamide block copolymers

Directory of Open Access Journals (Sweden)

M. Maric

2013-12-01

Full Text Available The homopolymerization of phenyl acrylate (PA was investigated for the first time by nitroxide mediated polymerization (NMP with the succinimidyl form of the SG1-based unimolecular initiator 2-[N-tert-butyl-2,2-(dimethylpropyl-aminooxy]propionic acid (BlocBuilder MA. The control of PPA homopolymerization was improved by the use of 15 mol% additional free nitroxide SG1 ([tert-butyl[1-(diethoxyphosphoryl-2,2-dimethylpropyl]amino]oxidanyl and dispersities, Mw/Mn, of around 1.2 were achieved. A PPA homopolymer was then successfully chain-extended with diethyl acrylamide (DEAAm to form a block copolymer of PPA-b-PDEAAm where the PDEAAm segment is thermo-responsive, while the PPA block is potentially UV-active. The thermo-responsive behavior of the block copolymer in 0.5 wt% aqueous solution was studied by UV-Vis spectrometry and dynamic light scattering (DLS, indicating cloud point temperatures of 26–30°C, close to that reported for PDEAAm homopolymers.

Synthesis and flocculation properties of gum ghatti andpoly(acrylamide-co-acrylonitrile) based biodegradable hydrogels

CSIR Research Space (South Africa)

Mittal, H

2014-12-01

Full Text Available This article reports the development of biodegradable flocculants based on graft co-polymers of gum ghatti (Gg) and a mixture of acrylamide and acrylonitrile co-monomers (AAm-co-AN). The hydrogel polymer exhibited an excellent swelling capacity...

Dissolution and Solubility Enhancement of the Highly Lipophilic Drug Phenytoin via Interaction with Poly(N-isopropylacrylamide-co-vinylpyrrolidone) Excipients.

Science.gov (United States)

Widanapathirana, Lakmini; Tale, Swapnil; Reineke, Theresa M

2015-07-06

Excipients of natural or synthetic origin play an important role in pharmaceutical performance to enhance the solubility, bioavailability, release, and stability of insoluble drugs. Herein, a series of seven excipient models was prepared by both homopolymerization and copolymerization of 1-vinyl-2-pyrrolidone (VP) and N-isopropylacrylamide (NIPAAm) by free radical polymerization yielding two homopolymers poly(VP) and poly(NIPAAm) and five copolymers of poly(NIPAAm-co-VP) at difference compositions. While the VP monomer provided aqueous solubility at a variety of conditions to the excipient, the incorporation of NIPAAm into the copolymer offered additional hydrogen bond donating sites to optimize the drug-polymer interactions in the system. Due to the presence of NIPAAm, the copolymers were sensitive to temperature as well. It was found that as the proportion of VP was increased (from 0 to 100%), the lower critical solution temperature (LCST) and the water solubility of the polymer models increased. To examine the role of specific drug-polymer interactions during dissolution on drug solubility and bioavailability, the polymers were formulated with the anticonvulsant drug phenytoin, which is a poorly water-soluble BCS class II drug where oral absorption is limited by the drug solubility. Amorphous solid dispersions (ASD) were prepared via spray drying of phenytoin with the polymer excipient models to contain 10% and 25% by weight drug loading. Physical characterization of the ASDs by powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) revealed that the polymers held the drug in a high-energy amorphous phase in all the formulations prepared. All ASDs exhibited improved in vitro dissolution rates compared to drug only and physical mixtures of the polymers and the drug. Drug solubility was the highest with the ASDs containing poly(NIPAAm-co-VP) 60:40 and 50:50, which showed a solubility enhancement of near 14-fold increase compared to pure drug

Small-angle neutron scattering from poly(NIPA-co-AMPS) gels

DEFF Research Database (Denmark)

Travas-Sejdic, J.; Easteal, A.; Knott, R.

2000-01-01

was reversed; that is the lower cross-link density, the higher the scattered intensity. Therefore, the role of cross-links at high temperature was to suppress microphase separation. The fitting of the experimental data with the Rabin and Panyukov theory indicated qualitative agreement.......The microstructure of the poly( N-isopropylacrylamide-co-acrylamido- 2-methyl-1-propane sulphonic acid) gel, poly( NIPA-co-AMPS), was investigated as a function of temperature and cross-link density using the small angle neutron scattering technique. The sample temperature was varied in the range...... 30 to 55C. Two different behaviours of poly( NIPA-co-AMPS) gels were observed. At low temperature (30C), the magnitude of the scattered intensity increased with cross-link density suggesting that additional cross-links introduced more inhomogeneities in the gel network. At high temperatures the trend...

Water absorption and mechanical properties of water-swellable natural rubber

Directory of Open Access Journals (Sweden)

Diew Saijun

2009-11-01

Full Text Available Water-swellable rubber (WSR was prepared by blending superabsorbent polymer (SAP of crosslinked poly(acrylamide-co-sodium acrylate with natural rubber in latex condition. The crosslinked poly(acrylamide-co-sodium acrylate was first prepared by inverse suspension polymerization from acrylamide and sodium acrylate monomers with potassiumpersulfate initiator and N,N-methylenebisacrylamide crosslinker. The reaction was carried out at 60oC for 40 mins. Water absorption properties, such as the degree of water absorption, water absorption rate, degree of weight loss, and mechanicalproperties of WSR were then investigated. It was found that the degree of water absorption, water absorption rate, and thedegree of weight loss increased, while tensile strength and elongation at break decreased with increasing quantity of SAP inthe blends. However, the degree of water absorption, degree of weight loss, and elongation at break decreased, but tensilestrength increased with increasing quantity of the N-tert-butyl-2-benzothiazyl sulphenamide (TBBS accelerator used in thecompounds formulation.

Avaliação da interação macromolécula/íon Zn+2 em meio aquoso: poli(acrilamida-co-ácido acrílico e taninos Estimation of the macromolecules/zinc ion interaction in the aqueous solution: poly(acrylamide-co-acrylic acid and tannins

Directory of Open Access Journals (Sweden)

Márcia D. Clarisse

2000-09-01

Full Text Available Este trabalho visa o estudo da interação entre polímeros sintéticos e produtos naturais à base de taninos com o íon zinco (Zn+2 em meio aquoso para sua utilização na remoção de metais em efluentes. Uma série de copolímeros poli(acrilamida-co-ácido acrílico de diferentes composições e homopolímeros de acrilamida e de ácido acrílico foram preparados, assim como, taninos comerciais foram utilizados como recebidos e purificados por extração. Uma metodologia de avaliação da eficiência de interação da macromolécula com o íon Zn+2 foi desenvolvida baseada em curva padrão de intensidade de absorção na região do ultravioleta-visível (UV-VIS em função da concentração do complexo formado, utilizando colorimetria. A capacidade de interação com o íon zinco foi ligeiramente maior para os polímeros sintéticos porém o produto natural tem a vantagem de apresentar um custo mais baixo.The aim of this work was to evaluate the interaction between natural and synthetic macromolecules with the zinc ion (Zn+2 in aqueous solution. Polyacrylamide, poly(acrylic acid and poly(acrylamide-co-acrylic acid were prepared and natural products (tannins were extracted and purified from commercial products. The methodology to evaluate the macromolecule/zinc ion interaction was based on colorimetry by using a standard curve. The interaction efficiency was slightly larger for the synthetic macromolecules when compared to the natural one. Nevertheless, the tanning has lower cost and its use could be recommended.

Poly[n]catenanes: Synthesis of molecular interlocked chains

Science.gov (United States)

Wu, Qiong; Rauscher, Phillip M.; Lang, Xiaolong; Wojtecki, Rudy J.; de Pablo, Juan J.; Hore, Michael J. A.; Rowan, Stuart J.

2017-12-01

As the macromolecular version of mechanically interlocked molecules, mechanically interlocked polymers are promising candidates for the creation of sophisticated molecular machines and smart soft materials. Poly[n]catenanes, where the molecular chains consist solely of interlocked macrocycles, contain one of the highest concentrations of topological bonds. We report, herein, a synthetic approach toward this distinctive polymer architecture in high yield (~75%) via efficient ring closing of rationally designed metallosupramolecular polymers. Light-scattering, mass spectrometric, and nuclear magnetic resonance characterization of fractionated samples support assignment of the high-molar mass product (number-average molar mass ~21.4 kilograms per mole) to a mixture of linear poly[7-26]catenanes, branched poly[13-130]catenanes, and cyclic poly[4-7]catenanes. Increased hydrodynamic radius (in solution) and glass transition temperature (in bulk materials) were observed upon metallation with Zn2+.

Por un sistema de interpretación de los procesos de regionalización e integración andina desde el análisis de políticas publicas

Directory of Open Access Journals (Sweden)

Catalina Toro Pérez

2007-01-01

Full Text Available En Colombia son mas bien recientes, los estudios de investigación sobre el proceso de integración andina y latinoamericana, en tiempos donde, sus relaciones internacionales, oscilan entre una inserción subordinada a los Estados Unidos y su aislamiento frente a los países vecinos, en una solitaria cruzada de por el restablecimiento del mito de la seguridad nacional, la autoridad y el orden en una sociedad que parece, al mismo tiempo, desintegrarse y fragmentarse cada día mas. Sin embargo, mientras el proceso de integración de la Comunidad Andina languidece, un nuevo tipo de regionalización política suramericana, se abre paso, impulsado por movimientos sociales y gobiernos alternativos de Ecuador, Venezuela, Bolivia, Argentina, y Brasil quienes en medio de grandes contradicciones, comienzan a constituir un frente común, contra las políticas de regionalización impuestas por los Estados Unidos, en materia de seguridad, defensa y comercio en el área andina. En un contexto de desintegración andina y de fractura social interna, como abordar la historia de los procesos de integración andina, sus conflictos y sus alternativas de construcción de practicas políticas comunes? Con el fin de aportar a la construcción de un marco de interpretación de los Procesos de Regionalización e Integración Andina, recogemos la contribución reciente de investigadores europeos que desde el campo de la sociología de la acción pública, abordan el análisis de la experiencia comunitaria europea. Luego a partir de diversas aproximaciones a los procesos de Integración andina en particular y latinoamericana en general, arrojamos una primera propuesta de interpretación desde el campo del análisis de las Políticas Publicas.

The study of poly-Si n+pp+ solar cells

International Nuclear Information System (INIS)

Aboud, S.R.

1990-01-01

The electrical and optical properties such as (activation energy, optical energy gap, and gap state density) of the polycrystalline silicon (poly-Si) have been studied. A comparative study between the chemical and mechanical polishing to clean and polish the poly-Si surface were done through the measurement of the reflectivity of these surfaces. A group of solar cells of type n + pp + were prepared, using p-type poly-Si wafers (SISLO). Solar cells were also prepared using single silicon (Sing-Si) with and, without (BSF) to study the effect of (BSF) on Sing-Si cell and a comparative study between poly-Si cell and Sing-Si cell under the same conditions. 2 tabs.; 45 figs.; 49 refs

N-isopropyl-123I-p-iodoamphetamine uptake mechanism in the lung - is it dependent on pH, lipophilicity or pKa?

International Nuclear Information System (INIS)

Akber, S.F.

1991-01-01

The uptake and binding mechanism of biogenic amines in the lungs has been studied extensively with no conclusive results. The competition between N-isopropyl- 123 I-p-iodo amphetamines ( 123 I-IMP) and propranolol and 123 I-IMP and ketamine, in the lungs suggest that the pK a value of the biogenic amines has a significant role to play in the mechanism of uptake and retention of biogenic amines in the lungs. (orig.) [de

Dual drug encapsulated thermo-sensitive fibrinogen-graft-poly (N-isopropyl acrylamide) nanogels for breast cancer therapy.

Science.gov (United States)

Rejinold, N Sanoj; Baby, Thejus; Chennazhi, K P; Jayakumar, R

2014-02-01

5-FU/Megestrol acetate loaded fibrinogen-graft-PNIPAAm Nanogels (5-FU/Meg-fib-graft-PNIPAAm NGs) were prepared for thermo responsive drug delivery toward α5β1-integrins expressing breast cancer cells in vitro (MCF-7 cells). The 60-100 nm sized fib-graft-PNIPAAm nanogels (LCST=35 °C) were prepared by CaCl2 cross-linker. 5-FU/Meg-fib-graft-PNIPAAm NGs showed particle size of 165-195 nm size. The drug loading efficiency with 5-FU was 60% and 70% for Meg. "Drug release was greater above the lower critical solution temperature (LCST). Above LCST, drug release system triggers apopotosis and enhance toxicity to MCF-7 cells when compared to the equivalent dose of the free drug. This effect was due to the greater uptake of the drug by MCF-7 cells". 5-FU/Meg-fib-graft-PNIPAAm NGs is portrayed here as a new combinatorial thermo-responsive drug delivery agent for breast cancer therapy. Copyright © 2013 Elsevier B.V. All rights reserved.

Gold recovery onto poly(acrylamide-allylthiourea) hydrogels synthesized by treating with gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Kilic, A. Guelden [Hacettepe University, Department of Chemistry, 06532 Ankara (Turkey); Malci, Savas [Hacettepe University, Department of Chemistry, 06532 Ankara (Turkey); Celikbicak, Oemuer [Hacettepe University, Department of Chemistry, 06532 Ankara (Turkey); Sahiner, Nurettin [Hacettepe University, Department of Chemistry, 06532 Ankara (Turkey); Salih, Bekir [Hacettepe University, Department of Chemistry, 06532 Ankara (Turkey)]. E-mail: bekir@hacettepe.edu.tr

2005-08-15

Poly(acrylamide-1-allyl-2-thiourea) hydrogels, Poly(AAm-ATU), were synthesized by gamma irradiation using a {sup 60}Co {gamma} source at different irradiation dose rates and in a monomer mixture with different 1-allyl-2-thiourea contents. These hydrogels were used for the specific gold recovery from single and competitive media. It was observed that the gold adsorption capacity onto the hydrogels was high at low pHs and reached a maximum value at pH 0.5. It was found that the adsorption capacity of the hydrogels for gold ions in acidic media around pH 0.5 was high and about 940 mg g{sup -1} dry hydrogel. Adsorption of these hydrogels for gold ions was found to be very fast and also these hydrogels were showed extremely high selectivity to the gold ions in acidic media even when the concentrations of the other metal ions were extremely higher than that of the gold. Because of the high specificity of these hydrogels to gold ions compared with the other metal ions at low pHs, all matrix effects could be easily eliminated by adsorbing gold ions onto the hydrogels at around pH 0.5 and desorbing into 0.8 M thiourea in 3.0 M HCl. The swellability of the synthesized hydrogels varied with irradiation dose rates and increased at high irradiation dose rates. The minimum swellability of the hydrogels was found to be at least 1000% which made it attractive for gold to penetrate into the hydrogels and react with all the functional groups in the interior surface of the hydrogels.

Poly(ethylene-co-butylene) functionalized multi walled carbon nanotubes applied in polypropylene nanocomposites

DEFF Research Database (Denmark)

Daugaard, Anders Egede; Jankova Atanasova, Katja; Marín, Jose Manuel Roman

2012-01-01

A novel functionalized multi walled carbon nanotube (MWCNT) was prepared through grafting with α-azido-poly(ethylene-co-butylene) (PEB-N3). The PEB-N3 was prepared through a two step procedure and grafted onto an industrial grade multi walled carbon nanotube (MWCNT) through a highly efficient...

Radiation grafting of acrylamide and maleic acid on chitosan and effective application for removal of Co(II) from aqueous solutions

Science.gov (United States)

Saleh, Alaaeldine Sh.; Ibrahim, Ahmed G.; Elsharma, Emad M.; Metwally, Essam; Siyam, Tharwat

2018-03-01

The graft copolymerization has been proven as a superior polymerization technique because it combines the functional advantages of the grafted and base polymers. In this work, the radiation-induced grafting of acrylamide (AAm) and maleic acid (MA) onto chitosan (CTS) was developed and optimized by determining the grafting percentage and efficiency as a function of grafting conditions such as AAm, MA, and CTS concentrations, and absorbed dose. Fourier transform infrared spectroscopic analysis (FTIR) confirmed the graft copolymerization. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) further characterized the grafted copolymers and showed their high thermal stability. Using batch sorption experiments and 60Co as a radiotracer, poly(CTS-AAm) and poly(CTS-MA) were evaluated for Co(II) removal from aqueous solutions. The Co(II) removal increases with increasing time, pH, polymer, and Co(II) concentrations. Experimentally, P(CTS-AAm) and P(CTS-MA) show high sorption capacities of Co(II), i.e. 150 mg g-1 and 421 mg g-1, respectively, which makes them potential sorbents of Co(II) for water and wastewater treatment. Finally, the Co(II) sorption was examined using sorption isotherm and kinetic models. The sorption was best fitted to Langmuir model which suggests the sorption is of chemisorption type. On the other hand, the sorption kinetics was best represented by Elovich model which also indicates the chemical nature of Co(II) sorption on P(CTS-AAm) and P(CTS-MA).

Atomistic simulation of CO 2 solubility in poly(ethylene oxide) oligomers

KAUST Repository

Hong, Bingbing

2013-10-02

We have performed atomistic molecular dynamics simulations coupled with thermodynamic integration to obtain the excess chemical potential and pressure-composition phase diagrams for CO2 in poly(ethylene oxide) oligomers. Poly(ethylene oxide) dimethyl ether, CH3O(CH 2CH2O)nCH3 (PEO for short) is a widely applied physical solvent that forms the major organic constituent of a class of novel nanoparticle-based absorbents. Good predictions were obtained for pressure-composition-density relations for CO2 + PEO oligomers (2 ≤ n ≤ 12), using the Potoff force field for PEO [J. Chem. Phys. 136, 044514 (2012)] together with the TraPPE model for CO2 [AIChE J. 47, 1676 (2001)]. Water effects on Henrys constant of CO2 in PEO have also been investigated. Addition of modest amounts of water in PEO produces a relatively small increase in Henrys constant. Dependence of the calculated Henrys constant on the weight percentage of water falls on a temperature-dependent master curve, irrespective of PEO chain length. © 2013 Taylor & Francis.

Atomic layer deposition of GeO{sub 2} thin films on Si(100) using Ge(N,N'-R,R-en)(NMe{sub 2}){sub 2} (where R = Isopropyl and t-Butyl) precursors

Energy Technology Data Exchange (ETDEWEB)

Kim, Dae Hyun; Shin, Jin Ho [Soulbrain Sigma-Aldrich Co., Ltd., Gongju (Korea, Republic of); Jung, Jae Sun; Kang, Jun Gill [Chungnam National University, Daejeon (Korea, Republic of)

2015-08-15

In this study, we introduced bis(dimethylamino)(N,N'-diisopropyl-ethylenediamine) germanium (1) and bis (dimethyl-amino)(N,N'-di-tert-butyl-ethylenediamine) germanium (2) as novel ALD precursors and analyzed the ALD growth characteristics to obtain the best possible film properties. A 5-L three-neck flask was charged with 2.5 L of toluene, GeCl{sub 4} (60 g, 0.28 mol) was added and then cooled to -15 to -20 .deg. C. the two precursors produced good-quality GeO{sub 2} thin films via the ALD process. The ALD windows of bis(dimethylamino)(N,N'-di-isopropyl-ethylenediamine) germanium and bis(dimethylamino)(N,N'-di-tert -butyl-ethylene-diamine) germanium were established at 200–330 .deg. C with a growth rate of about 0.40 and 0.31 Å/cycle, respectively. ALD-type growth mode was verified by increasing the precursor pulsing time. Growth rate was saturated from 3.0 s. These films have considerable potential for industrial applications.

Green-Yellow Electroluminescence from a host-dopant blended system as the active layer in a bilayer polymer light emitting diode: Poly(n-vinyl carbazole) as the host and a new soluble thiophene based copolymer [poly(2,2‧-BT)-co-(3-DDT)] as the dopant

Science.gov (United States)

Shahalizad, Afshin; Ahmadi-Kandjani, Sohrab; Movla, Hossein; Omidi, Hafez; Massoumi, Bakhshali; Zakerhamidi, Mohammad Sadegh; Entezami, Ali Akbar

2014-11-01

A new type of bilayer Polymer Light Emitting Diode (PLED) which emits green-yellow light is reported. In this PLED, a novel thiophene-based copolymer [poly(2,2‧-BT)-co-(3-DDT)] with an excellent electron transporting property has been doped in hole transporting and electron blocking poly(n-vinylcarbazole) (PVK). Formation of type-II heterojunctions among nm-size features in PVK:poly(2,2‧-BT)-co-(3-DDT) blended system makes exciplex and electroplex emissions would be dominant in the Electroluminescence (EL) spectrum of the device. These cross recombinations between electrons in the LUMO of poly(2,2‧-BT)-co-(3-DDT) and holes in the HOMO of PVK is a reason for the low driving voltage of the PLED because there is no need for the charge carriers to hop or tunnel to the adjacent polymer. Morphological investigations demonstrate that the mixing degree between the components is high, favoring formation of exciplexes and electroplexes at the interface of the components.

Increased accumulation of N-isopropyl-p-(123I)-iodoamphetamine in two cases with mitochondrial encephalomyopathy with lactic acidosis and strokelike episodes (MELAS)

International Nuclear Information System (INIS)

Morita, K.; Ono, S.; Fukunaga, M.; Morita, R.; Yasuda, T.; Higashi, Y.; Terao, A.

1989-01-01

We present two cases with mitochondrial encephalopathy with lactic acidosis and strokelike episodes (MELAS), which showed both increased and decreased accumulation of N-isopropyl-p-( 123 I)-iodoamphetamine ( 123 I-IMP) in single photon emission computed tomography (SPECT). The increased accumulation of the tracer occurred before low density appeared on conventional computed tomography, suggesting that 123 I-IMP SPECT may be useful in pathophysiological study of MELAS. (orig.)

Surface Modifications of Polymers Induced by Heavy Ions Grafting

Energy Technology Data Exchange (ETDEWEB)

Mazzei, R O; Lombardo, J; Camporotondi, D; Tadey, D; Bermudez, G G [National Atomic Energy Commission, Ezeiza Atomic Centre, Ezeiza (Argentina)

2012-09-15

Polymer surfaces are modified by the application of swift heavy ions etching and grafting procedures. The residual active sites produced by heavy ion beams, remaining after the etching process, were used to start the grafting process. In order to produce tracks on foils of poly(vinylidene fluoride) (PVDF) they were irradiated with {sup 208}Pb of 25.62 MeV/n or with 115 MeV Cl ions. Moreover, foils of polypropylene (PP) were irradiated with {sup 208}Pb of 25.62 MeV/n. Then, they were etched and grafted with N-isopropylacrylamide (NIPAAm) monomers or with acrylic acid (AAc) monomers, respectively. The replica method allowed the observation of the shape of the grafted tracks using transmission electron microscopy (TEM). In addition NIPAAm grafted foils were analyzed using Fourier transform infrared spectroscopy (FTIR). The sulfonation procedure (methodology previously described for perfluorated polymers) was applied on grafted PVDF. A new method is described to produce a thin layer of poly-acrylic-acid (membranes) that grows on the surface of PVDF foils implanted by an Ar{sup +} beam with energies between 30-150 keV. Different combinations of monomers in water solutions were used such as: acrylic acid (AAc); acrylic acid-glycidyl methacrylate (AAc-GMA); acrylic acid-styrene (AAc-S); acrylic acid-N-isopropyl acrylamide (AAc-NIPAAm) and acrylic acid-N-isopropyl acrylamide - glycidyl methacrylate (AAc-NIPAAm-GMA). The experimental results show that for particular values of: ion fluence and energy, AAc concentration, sulphuric acid and PVDF polymorphous (alpha or beta) a huge percentage of grafting was obtained. At certain point of the grafting process the development of the PolyAAc-Xmonomer produce a detachment from the irradiated substrate and continue its grafting outside it. This method produces a membrane that is an increased replica of the original implanted surface. Finally, PVDF films implanted by an Ar{sup +} beam with energies about 100 keV and a fluence of 10

Green synthesis of antimicrobial and antitumor N,N,N-trimethyl chitosan chloride/poly (acrylic acid)/silver nanocomposites.

Science.gov (United States)

Abu Elella, Mahmoud H; Mohamed, Riham R; Abdel-Aziz, Marwa M; Sabaa, Magdy W

2018-05-01

The present study is imported to solve two critical problems we face in our daily life which are microbial pollution and colon cancer. One pot green synthesis of a water soluble polyelectrolyte complex (PEC) between cationic polysaccharide as N,N,N-trimethyl chitosan chloride (TMC) and anionic polymer as poly (acrylic acid) (PAA) in presence of silver nanoparticles to yield (TMC/PAA/Ag) nanocomposites with different Ag weight ratios. Structure of TMC, PAA and TMC/PAA (PEC) were proved via different analysis tools. TMC/PAA and its Ag nanocomposites are used as antimicrobial agents against different pathogenic bacteria and fungi to solve microbial pollution. TMC/PAA-Silver nanocomposites had the highest antimicrobial activity which increases with increasing Ag %. Cytotoxicity data confirmed also that TMC/PAA/Ag (3%) had the most cytotoxic effect (the less cell viability %) towards colon cancer. TMC/PAA (PEC) was formed through electrostatic interactions between N-quaternized (-N + R 3 ) groups in TMC and carboxylate (-COO - ) groups in PAA. Copyright © 2018 Elsevier B.V. All rights reserved.

Optical and rheological studies on weak gel-sol transition in aqueous solutions of poly(N-isopropylacrylamide-block-polystyrene

Directory of Open Access Journals (Sweden)

S. Sanjeevi Prasath

2017-07-01

Full Text Available The optical and rheological properties of aqueous solutions of block copolymer composed of low molecular weight poly(N-isopropylacrylamide-b-polystyrene are studied as a function of temperature. From light scattering measurements the block copolymer solution is found to form micelles at very low concentrations and the critical micellar concentration is identified as 0.005 wt%. Apart from the concentration dependence, a unique temperature dependent micelle formation is noted at 34 °C. Further, temperature dependent refractive index measurements shows that the refractive index increases with temperature (beyond the lower critical solution temperature, 31.6 °C of the polymer, and is attributed to the stable rearrangement of the proximal hydrophobic isopropyl-polystyrene chains in the collapsed polymer so as to overcome the steric hindrance effects offered by the hydrophobic chains. In the polymer concentrations investigated for rheological studies, the solution flows, yet manifested solid like behavior with G' > G" with the modulus being frequency dependent and the magnitude of G' two-fold higher than G" implying a weak gel state. Weak gel states are in general noted at high temperatures in most of the polymer systems, contrary to this, in our studies weak gel state is observed at lower temperature. Further, a transition from weak gel to sol state is observed at slightly elevated temperatures. The reason for the existence of weak gel state below the lower critical solution temperature is due to the micellar entanglements of poly(N-isopropylacrylamide-b-polystyrene with one another and whereas above the lower critical solution temperature disentanglement of the micelles makes the system behave like a viscoelastic liquid.

Molecular Nickel Phosphide Carbonyl Nanoclusters: Synthesis, Structure, and Electrochemistry of [Ni11P(CO)18]3- and [H6-nNi31P4(CO)39]n- (n = 4 and 5).

Science.gov (United States)

Capacci, Chiara; Ciabatti, Iacopo; Femoni, Cristina; Iapalucci, Maria Carmela; Funaioli, Tiziana; Zacchini, Stefano; Zanotti, Valerio

2018-02-05

The reaction of [NEt 4 ] 2 [Ni 6 (CO) 12 ] in thf with 0.5 equiv of PCl 3 affords the monophosphide [Ni 11 P(CO) 18 ] 3- that in turn further reacts with PCl 3 resulting in the tetra-phosphide carbonyl cluster [HNi 31 P 4 (CO) 39 ] 5- . Alternatively, the latter can be obtained from the reaction of [NEt 4 ] 2 [Ni 6 (CO) 12 ] in thf with 0.8-0.9 equiv of PCl 3 . The [HNi 31 P 4 (CO) 39 ] 5- penta-anion is reversibly protonated by strong acids leading to the [H 2 Ni 31 P 4 (CO) 39 ] 4- tetra-anion, whereas deprotonation affords the [Ni 31 P 4 (CO) 39 ] 6- hexa-anion. The latter is reduced with Na/naphthalene yielding the [Ni 31 P 4 (CO) 39 ] 7- hepta-anion. In order to shed light on the polyhydride nature and redox behavior of these clusters, electrochemical and spectroelectrochemical studies were carried out on [Ni 11 P(CO) 18 ] 3- , [HNi 31 P 4 (CO) 39 ] 5- , and [H 2 Ni 31 P 4 (CO) 39 ] 4- . The reversible formation of the stable [Ni 11 P(CO) 18 ] 4- tetra-anion is demonstrated through the spectroelectrochemical investigation of [Ni 11 P(CO) 18 ] 3- . The redox changes of [HNi 31 P 4 (CO) 39 ] 5- show features of chemical reversibility and the vibrational spectra in the ν CO region of the nine redox states of the cluster [HNi 31 P 4 (CO) 39 ] n- (n = 3-11) are reported. The spectroelectrochemical investigation of [H 2 Ni 31 P 4 (CO) 39 ] 4- revealed the presence of three chemically reversible reduction processes, and the IR spectra of [H 2 Ni 31 P 4 (CO) 39 ] n- (n = 4-7) have been recorded. The different spectroelectrochemical behavior of [HNi 31 P 4 (CO) 39 ] 5- and [H 2 Ni 31 P 4 (CO) 39 ] 4- support their formulations as polyhydrides. Unfortunately, all the attempts to directly confirm their poly hydrido nature by 1 H NMR spectroscopy failed, as previously found for related large metal carbonyl clusters. Thus, the presence and number of hydride ligands have been based on the observed protonation/deprotonation reactions and the spectroelectrochemical

Clinical evaluation of brain perfusion scintigraphy using N-isopropyl-p-[123I]-iodoamphetamine

International Nuclear Information System (INIS)

Shimbo, Shin-ichiro; Yamamoto, Itsuo; Yagi, Kenji; Misaki, Takashi; Dokoh, Shigeharu

1989-01-01

The present study includes 16 patients with symptoms related to cerebrovascular insufficiency, who were randomly selected from out outpatient clinic of internal medicine. Single photon emission computed tomography (SPECT) with 111∼185 MBq (3∼5 mCi) of N-isopropyl-p-[ 123 I]-iodoamphetamine (IMP) was performed 20 min and 3 hr after intravenous administration of the tracer, and compared to the image of conventional X-ray computed tomography (X-CT). Out of twelve cases with significant findings in X-CT, 9 showed corresponding changes in perfusion in SPECT with IMP, and the remaining 3 did not. In a patient with cerebral infarction, SPECT revealed a perfusion defect whereas her X-CT was negative, thereby proved to be useful in determining the focus of clinically suspected stroke. There were some other cases in which findings in SPECT and X-CT were discordant. From our series of scans, SPECT seemed useful in detecting responsible sites of neurological deficits in early and, occasionally, remote phases of cerebrovascular accidents, while X-CT appeared superior in finding smaller lesions. (author)

Evaluation of SPECT with N-isopropyl[I-123]-p-iodoamphetamine (IMP) in epileptic patients

International Nuclear Information System (INIS)

Nambu, Toshikazu; Itoh, Kazuo; Sumi, Tetsuo; Furudate, Masayori; Irie, Goro

1988-01-01

Brain SPECT scintigrams with N-Isopropyl[I-123]-p-Iodoamphetamine (IMP) were reviewed and compared with the EEG findings in 21 epileptic patients (22 SPECT images) with normal CT. Thirteen of 22 SPECT images showed abnormal low uptake and 7 of them corresponded to the EEG focus. In order to obtain the quantitative analysis, the count ratio of the focus side to the opposite I-123 content in fixed ROI was measured for each case, but no statistically significant correlation for the frequency or the duration of epilepsy was found. EEG is not considered to be favorite standard for localizing epileptic foci, especially in deep cerebral region, and that may be one of the main reason for the incomplete correlation. In the qualitative study, however, the cases with frequent epileptic attack were more likely to show abnormal findings. I-123 IMP SPECT can now be considered as having a significant clinical role for the diagnosis and management of patients with epilepsy. (author)

N-isopropyl-p-[I[sup 123

Energy Technology Data Exchange (ETDEWEB)

Tada, Hiroshi; Morooka, Keiichi; Arimoto, Kiyoshi; Matsuo, Takiko; Takagi, Kazue; Yanagawa, Etsuko (Toho Univ., Tokyo (Japan). School of Medicine)

1992-09-01

We studied the clinical usefulness of I[sup 123]-IMP SPECT in 50 pediatric patients with CNS disorders, which were categorized into the convulsive disorder group (n=20), the cerebrovascular disorder group (n=10), the acute encephalopathy or CNS infection group (n=10), the metabolic or degenerative disorder group (n=6), the congenital abnormality group (n=2) and the migraine group (n=2). The findings obtained were compared with those of cranial CT. I[sup 123]-IMP SPECT revealed abnormal findings in 45 out of the 50 patients (90%), although cranial CT showed abnormal findings in only 24 patients (48%). This difference was statistically significant (p<0.01). In all groups except the migraine, we could find abnormal findings in more than 90% of the patients. Out of 28 patients without focal findings on the initial CT scanning. I[sup 123]-IMP SPECT showed focal abnormalities in 26 patients (93%). Moreover in many patients with focal neurological abnormalities, we found focal abnormalities of I[sup 123]-IMP SPECT related with neurological abnormalities of the patients. From these findings, we think I[sup 123]-IMP SPECT might be superior to CT scanning in examining a localized lesion. It was found that in many patients with focal abnormalities in CT scanning, I[sup 123]-IMP SPECT showed larger abnormalities in CT scanning. By using I[sup 123]-IMP SPECT we might be able to study the blood perfusional state surrounding the abnormal area shown by CT. In 3 patients with acute cerebrovascular disorders, I[sup 123]-IMP SPECT revealed abnormal findings 3 to 11 days earlier than cranial CT. I[sup 123]-IMP SPECT might be useful for early recognition of the pathological state. From these experiences, we concluded that I[sup 123]-IMP SPECT was useful for studying the pathophysiology of CNS disorders in children. (author).

Synthesis of 2-Isopropyl Naphthalene Catalyzed by Et3NHCl-AlCl3 Ionic Liquids

Institute of Scientific and Technical Information of China (English)

Li Chenmin; Qi Xin; Tang Xiangyang

2014-01-01

In this paper, 2-isopropyl naphthalene has been synthesized by the reaction of naphthalene and isopropyl bromide, using triethylamine hydrochloride-aluminum chloride ionic liquid as the catalyst. The effect of the catalyst composition, the reaction time, the reaction temperature, the ionic liquid dosage, as well as the molar ratio of the reagents on the 2-isopropyl naphthalene yield was systematically investigated. The optimal reaction conditions cover:an AlCl3 to Et3NHCl ratio of 2.0, a reaction time of 3 h, a reaction temperature of 15.0℃, a volume fraction of ionic liquid to the mixture (isopropyl bromide, n-dodecane and n-hexane) of 9%, and a naphthalene/isopropyl bromide molar ratio of 4.0. Under the optimal reaction condi-tions, the conversion of isopropyl bromide reached 98%and the selectivity of 2-isopropyl naphthalene was equal to 80%. The test results veriifed good catalytic activity upon using Et3NHCl-AlCl3 ionic liquid as the catalyst for alkylation of naph-thalene with isopropyl bromide. The activity of the ionic liquid remains unchanged after it has been recycled for 4 times.

Living Polymerization of N -Substituted β-Alanine N -Carboxyanhydrides: Kinetic Investigations and Preparation of an Amphiphilic Block Copoly-β-Peptoid

KAUST Repository

Grossmann, Arlett

2012-07-03

Poly(α-peptoid)s (N-substituted polyglycines) are interesting peptidomimetic biomaterials that have been discussed for many applications. Poly(β-peptoid)s (N-substituted poly-β-alanines), although equally intriguing, have received much less attention. Here we present results that suggest that while N-substituted β-alanine N-carboxyanhydrides can undergo a living nucleophilic ring-opening polymerization, the solubility of poly(β-peptoid)s can be very poor, which contributes to the limited accessibility using other synthetic approaches. The living character of the polymerization was utilized for the preparation of the first polymerized amphiphilic block copoly-β-peptoid. Our results may open a new route towards highly defined functional poly(β-peptoid)s which could represent biomaterials. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Improved Method for Preparation of Amidoxime Modified Poly(acrylonitrile-co-acrylic acid: Characterizations and Adsorption Case Study

Directory of Open Access Journals (Sweden)

Nur Amirah Mohd Zahri

2015-07-01

Full Text Available Redox polymerization of poly(acrylonitrile-co-acrylic acid (poly(AN-co-AA is performed at 40 °C under N2 gas by varying the ratio of acrylonitrile (AN and acrylic acid (AA in the feed. The yield production of poly(acrylonitrile (PAN is 73% and poly(AN-co-AA with a feed ratio of 93:7 is the highest yield (72%. The PAN and poly(AN-co-AA are further chemically modify with hydroxylamine hydrochloride. The FTIR spectroscopy is used to confirm the copolymerization of poly(AN-co-AA and chemical modification of poly(AN-co-AA. Elemental microanalysis shows that the overall trend percentage of carbon, hydrogen, and nitrogen for all feed ratios are slightly decreasing as the feed ratio of AA is increasing except for poly(AN-co-AA 93:7. The SEM images shows that spherical diameter of poly(AN-co-AA is smaller compared to the PAN and amidoxime (AO modified poly(AN-co-AA. The TGA (thermogravimetric analysis analysis reveals that the poly(AN-co-AA degrades at lower temperatures compared to the PAN but higher than AO modified poly(AN-co-AA. The case study adsorption test showed that the AO modified poly(AN-co-AA 93:7 had the highest percentage removal of Cd2+ and Pb2+.

Entrappment of alkaline protease and {beta}-galactosidase in radiation stitched together poly-N-vinylcaprolactam.; Vklyuchenie shchelochnoj proteazy i {beta}-galaktozidazy v radiatsionno sshityj poli-N-vinilkaprolaktam.

Energy Technology Data Exchange (ETDEWEB)

Davidenko, T I; Kravchenko, I A [AN Ukrainskoj SSR, Odessa (Ukraine). Fiziko-Khimicheskij Inst.

1996-03-01

The gel formations by poly-N-vinylcaprolactam upon its {gamma}-irradiation by the 20-25 kGy dose as a results of partial polymer stitching together is shown, which is confirmed by the CD-and thermogravimetric data. By the alkaline protease and {beta}-galactosidase entrapment in poly-N- vinylcaprolactam stitched together by {gamma}-irradiation, the active preparations are obtained with 90-98 % and 30-35 % activity retained for alkaline protease and {beta}-galactosidase, respectively. The increased stability of alkaline protease at acidic pH values and higher temperature was noted, and for {beta}-galactosidase - the possibility of repeated use of the obtained preparation for lactose hydrolysis.

Electrochemical n-doping of poly(dithienylvinylene). A comparison of cyclovoltammetric and conductive properties in n- and p-doping

Energy Technology Data Exchange (ETDEWEB)

Zotti, G. (Ist. di Polarografia ed Elettrochimica Preparative, Consiglio Nazionale delle Ricerche, Padua (Italy)); Schiavon, G. (Ist. di Polarografia ed Elettrochimica Preparative, Consiglio Nazionale delle Ricerche, Padua (Italy))

1994-03-15

Electrochemical n-doping of poly(dithienylvinylene) has been performed in AN+0.1 M N(C[sub n]H[sub 2n+1])[sub 4][sup +]ClO[sub 4][sup -] (n=1,2,3,4 and 6) and compared with p-doping. Cyclic voltammetry, in situ ESR and UV-Vis spectroelectrochemistry show that radical anions produced in n-doping are moderately unstable towards disproportionation whereas, in p-doping, radical cations are stabilized by [pi]-dimerization. In situ conductivity of n-doped polymer decreases as the size of the dopant cation increases, suggesting charge transport control by interchain hopping. The different conductivities of n- and p-doped polymers are due to the different sizes of the counterions. (orig.)

Thermal analysis of polyaniline poly(N-vinylpyrrolidone)-stabilized dispersions

Czech Academy of Sciences Publication Activity Database

Peřinka, N.; Držková, M.; Hajná, Milena; Jašúrek, B.; Šulcová, P.; Syrový, T.; Kaplanová, M.; Stejskal, Jaroslav

2014-01-01

Roč. 116, č. 2 (2014), s. 589-595 ISSN 1388-6150 R&D Projects: GA TA ČR TE01020022 Institutional support: RVO:61389013 Keywords : polyaniline * poly(N-vinylpyrrolidone) * dispersion Subject RIV: CG - Electrochemistry Impact factor: 2.042, year: 2014

[Comparison of the acrylamide level in microwaved popcorn with that of ordinarily heated one].

Science.gov (United States)

Sun, Shiyu; Xia, Yongmei; Liu, Xuefeng; Hu, Xueyi

2007-03-01

To establish a method of examining acrylamide in cooked popcorn. Solid phase extraction/gas chromatography (SPE/GC) was established with N, N-dimethyl acrylamide as internal standard. The detection limit and the quantification limit were estimated at 3 microg/L and 10 microg/L, respectively, and the linear correlation coefficient was 0.9969. Seven commercial popcorn samples with different flavors were collected and tested in this paper. The RSD of acrylamide level of caramel sweet popcorn microwaved was 1.95 % (n = 6). When the commercial popcorns of caramel sweet and cream salted were microwaved (A and D) or conventional heated (A' and D'), the acrylamide levels reached [Am]A = 1017 microg/kg, [Am]D = 146.5 microg/kg, [Am]A, = 2206 microg/kg and [Am]D = 970.1 microg/kg, respectively. The microwaved popcorns tested are safer in general because the acrylamide level of them except that with high simple sugar content is obviously lower than that of ordinarily heated one.

Stimuli-responsive poly(N-vinylcaprolactam-co-2-methoxyethyl acrylate) core–shell microgels: facile synthesis, modulation of surface properties and controlled internalisation into cells†

NARCIS (Netherlands)

Melle, A.; Balaceanu, A.; Kather, M.; Wu, Yaodong; Gau, E.; Sun, W.; Huang, Xiaobin; Shi, X; Karperien, Hermanus Bernardus Johannes; Pich, A.

2016-01-01

Herein we report the synthesis of biocompatible stimuli-responsive core–shell microgels consisting of a poly(N-vinylcaprolactam) (PVCL) core and a poly(2-methoxyethyl acrylate) (PMEA) corona via one-step surfactant-free precipitation copolymerization. The copolymerization process was investigated by

Acrylamide-b-N-isopropylacrylamide block copolymers : Synthesis by atomic transfer radical polymerization in water and the effect of the hydrophilic-hydrophobic ratio on the solution properties

NARCIS (Netherlands)

Wever, Diego Armando Z.; Ramalho, Graham; Picchioni, Francesco; Broekhuis, Antonius Augustinus

2014-01-01

A series of block copolymers of acrylamide and N-isopropylacrylamide (NIPAM) characterized by different ratios between the length of the two blocks have been prepared through atomic transfer radical polymerization in water at room temperature. The solution properties of the block copolymers were

Clinical utility of N-isopropyl-p-[123I] iodoamphetamine (123I-IMP) for SPECT in epileptic children

International Nuclear Information System (INIS)

Taki, Kuniyasu; Seto, Hikaru; Futatsuya, Ryusuke; Kakishita, Masao; Seki, Hiroyasu.

1989-01-01

A regional cerebral perfusion study was performed in epileptic children using single photon emission computed tomography (SPECT) and N-isopropyl-p-[ 123 I] iodoamphetamine ( 123 I-IMP). A total of 22 patients with epilepsy underwent both a 123 I-IMP brain perfusion study and X-ray CT. Eighteen had positive and four had negative perfusion study results. Of the eighteen patients with positive perfusion study results, two were positive on X-ray CT. In these two patients, the areas of perfusion defects were larger than those of low density on X-ray CT. In only four patients did the areas of perfusion defects correspond to the sites of abnormal EEG. In conclusion, 123 I-IMP perfusion study is of great clinical value in pediatric epileptic cases. (author)

Investigation of anti-corrosive properties of poly(aniline-co-2-pyridylamine-co-2,3-xylidine) and its nanocomposite poly(aniline-co-2-pyridylamine-co-2,3-xylidine)/ZnO on mild steel in 0.1 M HCl

Science.gov (United States)

Alam, Ruman; Mobin, Mohammad; Aslam, Jeenat

2016-04-01

A soluble terpolymer of aniline (AN), 2-pyridylamine (PA) and 2,3-xylidine (XY), poly(AN-co-PA-co-XY) and its nanocomposite with ZnO nanoparticles namely, poly(AN-co-PA-co-XY)/ZnO were synthesized by chemical oxidative polymerization employing ammonium persulfate as an oxidant. Nanocomposites of homopolymers, polyaniline/ZnO, poly(XY)/ZnO and poly(PA)/ZnO were also synthesized by following similar synthesis route. FTIR, XRD and SEM techniques were used to characterize the synthesized compounds. The synthesized compounds were chemically deposited on mild steel specimens by solvent evaporation method using N-methyl-2-pyrrolidone (NMP) as solvent and 10% epoxy resin (by weight) as binder. Anticorrosive properties of homopolymer nanocomposites, terpolymer and its nanocomposite coatings were studied in 0.1 M HCl by subjecting them to various corrosion tests which includes: free corrosion potential measurement (OCP), weight loss measurements, potentiodynamic polarization, and AC impedance technique. The surface morphology of the corroded and uncorroded coated steel specimens was evaluated using SEM. The corrosion protection performance of terpolymer nanocomposite coating was compared to the terpolymer and individual homopolymers nanocomposites coatings after 30 days immersion in corrosive medium.

Synthesis and characterization of thermally stable poly(amide-imide-montmorillonite nanocomposites based on bis(4-carboxyphenyl-N,N'-pyromellitimide acid

Directory of Open Access Journals (Sweden)

M. Hajibeygi

2013-04-01

Full Text Available Two new poly(amide-imide-montmorillonite reinforced nanocomposites containing bis(4-carboxyphenyl-N,N'-pyromellitimide acid moiety in the main chain were synthesized by a convenient solution intercalation technique. Poly(amide-imide (PAI as a source of polymer matrix was synthesized by the direct polycondensation reaction of bis(4-carboxyphenyl-N,N'-pyromellitimide acid with 4,4'-diamino diphenyl sulfone in the presence of triphenyl phosphite (TPP, CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP. Morphology and structure of the resulting PAI-nanocomposite films with 10 and 20% silicate particles were characterized by FT-IR spectroscopy, X-ray diffraction (XRD and scanning electron microscopy (SEM. The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposites films were investigated by using UV-Vis spectroscopy, thermal gravimetry analysis (TGA and water uptake measurements.DOI: http://dx.doi.org/10.4314/bcse.v27i1.10

Fabrication and Evaluation of 2-Hydroxyethyl Methacrylate-co ...

African Journals Online (AJOL)

Purpose: To fabricate and evaluate oral 2-hydroxyethyl methacrylate co-acrylic acid hydrogels as a drug delivery system for sustained release of nicorandil. Methods: HEMA-co-AA hydrogels using different monomer concentrations were prepared by free radical polymerization. N, N-methylene bis acrylamide (MBA) was ...

Determination of acrylamide in Thai-conventional snacks from Nong Mon market, Chonburi using GC-MS technique.

Science.gov (United States)

Komthong, P; Suriyaphan, O; Charoenpanich, J

2012-01-01

Acrylamide in Thai-conventional snacks was analysed by GC/MS with a linear response ranged of 5-50 µg and r² > 0.99. The limit of detection (s/n = 3) and limit of quantification (s/n = 10) were 4 and 15 µg kg⁻¹, respectively, and RSD Chinese wonton. Acrylamide was lowest (tourists indicate a daily intake of acrylamide <150 ng, well below a toxic dose.

Fabrication of chitosan-g-poly(acrylamide)/CuS nanocomposite for controlled drug delivery and antibacterial activity

Energy Technology Data Exchange (ETDEWEB)

Pathania, Deepak, E-mail: dpathania74@gmail.com [School of Chemistry, Shoolini University of Biotechnology and Management Sciences, Solan, H.P. (India); Gupta, Divya [School of Chemistry, Shoolini University of Biotechnology and Management Sciences, Solan, H.P. (India); Agarwal, Shilpi [Department of Applied Chemistry, University of Johannesburg, Johannesburg (South Africa); Asif, M. [Chemical Engineering Department, King Suad University Riyadh (Saudi Arabia); Gupta, Vinod Kumar [Department of Applied Chemistry, University of Johannesburg, Johannesburg (South Africa); Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee, 247667 (India)

2016-07-01

In present study, we reported the synthesis of chitosan-g-poly(acrylamide)/CuS (CPA/CS) nanocomposite for controlled delivery of ofloxacin. The CPA/CS nanocomposites were characterized by Fourier transmission infrared spectroscopy (FTIR), UV–visible spectroscopy (UV), scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis. From the FTIR spectra, the various groups present in CPA/CS nanocomposite were monitored. The homogeneity, morphology and crystallinity of the CPA/CS nanocomposite were ascertained from SEM/EDX and XRD data, respectively. The kinetics of ofloxacin drug delivery was investigated at different pH. The drug released studies were investigated at different pH (2.2, 7.4 and 9.4) and time intervals (2, 4, 6, 8, 10, 12, 14, 16 h). The drug release behavior depends upon the pH of medium and the nature of matrix. The maximum drug loading efficiency of 85% was recorded for CPA/CS. The maximum drug release of 76% was observed at 2.2. pH after 18 h onto CPA/CS. Nanocomposites were also tested for antibacterial activity against Escherichia coli bacteria. About 97% killing of E. coli was observed after 24 h. - Highlights: • Chitosan-g-poly(acrylamide)/CuS (CPA/CS) nanocomposite has been synthesized in microwave reactor. • Different spectral techniques confirmed the formation of nanocomposite. • The drug release behavior of CPA/CS nanocomposites were studied at different pH and different time interval. • CPA/CS has been investigated for an excellent antibacterial activity against E. coli bacterial culture.

Fabrication of chitosan-g-poly(acrylamide)/CuS nanocomposite for controlled drug delivery and antibacterial activity

International Nuclear Information System (INIS)

Pathania, Deepak; Gupta, Divya; Agarwal, Shilpi; Asif, M.; Gupta, Vinod Kumar

2016-01-01

In present study, we reported the synthesis of chitosan-g-poly(acrylamide)/CuS (CPA/CS) nanocomposite for controlled delivery of ofloxacin. The CPA/CS nanocomposites were characterized by Fourier transmission infrared spectroscopy (FTIR), UV–visible spectroscopy (UV), scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis. From the FTIR spectra, the various groups present in CPA/CS nanocomposite were monitored. The homogeneity, morphology and crystallinity of the CPA/CS nanocomposite were ascertained from SEM/EDX and XRD data, respectively. The kinetics of ofloxacin drug delivery was investigated at different pH. The drug released studies were investigated at different pH (2.2, 7.4 and 9.4) and time intervals (2, 4, 6, 8, 10, 12, 14, 16 h). The drug release behavior depends upon the pH of medium and the nature of matrix. The maximum drug loading efficiency of 85% was recorded for CPA/CS. The maximum drug release of 76% was observed at 2.2. pH after 18 h onto CPA/CS. Nanocomposites were also tested for antibacterial activity against Escherichia coli bacteria. About 97% killing of E. coli was observed after 24 h. - Highlights: • Chitosan-g-poly(acrylamide)/CuS (CPA/CS) nanocomposite has been synthesized in microwave reactor. • Different spectral techniques confirmed the formation of nanocomposite. • The drug release behavior of CPA/CS nanocomposites were studied at different pH and different time interval. • CPA/CS has been investigated for an excellent antibacterial activity against E. coli bacterial culture.

Improvement in the water retention characteristics of sandy loam soil using a newly synthesized poly(acrylamide-co-acrylic acid)/AlZnFe2O4 superabsorbent hydrogel nanocomposite material.

Science.gov (United States)

Shahid, Shaukat Ali; Qidwai, Ansar Ahmad; Anwar, Farooq; Ullah, Inam; Rashid, Umer

2012-08-03

The use of some novel and efficient crop nutrient-based superabsorbent hydrogel nanocomposites (SHNCs), is currently becoming increasingly important to improve the crop yield and productivity, due to their water retention properties. In the present study a poly(Acrylamide-co-acrylic acid)/AlZnFe2O4 superabsorbent hydrogel nanocomposite was synthesized and its physical properties characterized using Energy Dispersive X-ray (EDX), FE-SEM and FTIR spectroscopic techniques. The effects of different levels of SHNC were studied to evaluate the moisture retention properties of sandy loam soil (sand 59%, silt 21%, clay 19%, pH 7.4, EC 1.92 dS/m). The soil amendment with 0.1, 0.2, 0.3 and 0.4 w/w% of SHNC enhanced the moisture retention significantly at field capacity compared to the untreated soil. Besides, in a separate experiment, seed germination and seedling growth of wheat was found to be notably improved with the application of SHNC. A delay in wilting of seedlings by 5-8 days was observed for SHNC-amended soil, thereby improving wheat plant growth and establishment.

Por un sistema de interpretación de los procesos de regionalización e integración andina desde el análisis de políticas públicas

Directory of Open Access Journals (Sweden)

Catalina Toro Pérez

2008-07-01

Full Text Available Este artículo pretende abordar la historia reciente de los estudios sobre integración y regionalización andina, desde el campo de análisis de las políticas públicas. Frente a una tradición analítica amparada por el debate entre inter- gubernamentalistas y neo-funcionalistas, los estudios de la “regionalización” coinciden con la consolidación del campo de las políticas públicas y su expansión hacia otras sub-disciplinas de la ciencia política con útiles metodológicos, como el análisis multinivel de la nueva gobernanza, los análisis cognitivos y la acción colectiva, así como los estudios sobre la inserción de redes epistémicas en los procesos de toma de decisión global. Frente esta enorme influencia en el ámbito académico centroeuropeo y anglosajón, América Latina posee una rica e importante tradición analítica a partir de los análisis sobre las transformaciones del rol del Estado y de sus estructuras de poder. A partir de la economía política crítica aporta no solamente una dimensión histórica a los estudios de los procesos de integración actual, sino también una dimensión socio-económica y geopolítica de su contexto en el cambiante sistema capitalista mundial. Desde esta perspectiva, las instituciones regionales andinas, como la CAN, no estarían ausentes de una visión de orden mundial hegemónica, que se expresaría en formas históricas y simbólicas de dominación. Frente a las tendencias de regionalismo abierto y libre comercio y con ellas la emergencia de nuevas coaliciones de actores, asociados a los Estados capitalistas centrales se plantea entonces una perspectiva crítica que permita una construcción alternativa a las propuestas de integración subordinadas a los sistemas de representaciones del “orden mundial”.

Scintigraphy of cerebral blood flow with N-isopropyl-p-[123I]-iodoamphetamine in cerebrovascular accident

International Nuclear Information System (INIS)

Sone, Teruki; Fukunaga, Masao; Otsuka, Nobuaki

1985-01-01

In 20 patients with cerebrovascular accident, cerebral blood flow was estimated with N-isopropyl-p-[ 123 I]-iodoamphetamine ( 123 I-IMP) using a rotating gamma camera, and the findings were compared with those of X-CT or angiography. 123 I-IMP study demonstrated the areas of diminished cerebral blood flow in 14 cases. X-CT also demonstrated lesions in 14 cases, however, 123 I-IMP study delineated the lesions more precisely corresponding to the neurological findings. In cases with cerebellar hemorrhage or reversible ischemic neurological deficit (RIND), the lesion could be established only by 123 I-IMP study. It was demonstrated by 123 I-IMP study that vascular stenosis or abnormal vessels seen on angiography in patients with vertebro-basilar insufficiency or venous angioma was not necessarily accompanied by diminished blood flow. It was shown that scintigraphy with 123 I-IMP was a non-invasive, safe and extremely useful method to estimate the regional cerebral blood flow. (author)

N-isopropyl I-123 p-iodoamphetamine brain scintigraphy with SPECT in Creutzfeldt-Jakob disease

Energy Technology Data Exchange (ETDEWEB)

Momose, Toshimitsu; Kosaka, Noboru; Nishikawa, Junichi; Ohtake, Tohru; Watanabe, Toshiaki; Yoshikawa, Kohki; Iio, Masahiro

1988-10-01

Two patients of clinically diagnosed Creutzfeldt-Jakob disease (CJD) were examined with N-Isopropyl I-123 p-Iodoamphetamine (IMP) SPECT, MRI and XCT. Both patient has myoclonus and severe conscious disturbance with periodic synchronized discharge (PSD) on EEG. SPECT images were obtained using GE400AC/T. Regional IMP uptake was determined by calculating the ratio of each cortical regional to cerebellar IMP uptake (cortico-cerebellar ratio: CCR) and compared with that of five normal controls. In both case, CCR was remarkably decreased in all cortical areas, although XCT or MRI shows no abnormality except slight cortical atrophy. It suggests that metabolic and functional changes proceed morphological abnormality seen on XCT or MRI. In one case of CJD, serial studies of SPECT and XCT were performed after three months of interval. CCR in second study was higher than in first study, while XCT revealed remarkable brain atrophy including cerebrum, pons and cerebellum. It can be interpreted as regional differences of disease process. In conclusion, I-123 IMP-SPECT is useful for the earlier detection of lesions in CJD.

N-isopropyl I-123 p-iodoamphetamine brain scintigraphy with SPECT in Creutzfeldt-Jakob disease

International Nuclear Information System (INIS)

Momose, Toshimitsu; Kosaka, Noboru; Nishikawa, Junichi; Ohtake, Tohru; Watanabe, Toshiaki; Yoshikawa, Kohki; Iio, Masahiro

1988-01-01

Two patients of clinically diagnosed Creutzfeldt-Jakob disease (CJD) were examined with N-Isopropyl I-123 p-Iodoamphetamine (IMP) SPECT, MRI and XCT. Both patient has myoclonus and severe conscious disturbance with periodic synchronized discharge (PSD) on EEG. SPECT images were obtained using GE400AC/T. Regional IMP uptake was determined by calculating the ratio of each cortical regional to cerebellar IMP uptake [cortico-cerebellar ratio: CCR] and compared with that of five normal controls. In both case, CCR was remarkably decreased in all cortical areas, although XCT or MRI shows no abnormality except slight cortical atrophy. It suggests that metabolic and functional changes proceed morphological abnormality seen on XCT or MRI. In one case of CJD, serial studies of SPECT and XCT were performed after three months of interval. CCR in second study was higher than in first study, while XCT revealed remarkable brain atrophy including cerebrum, pons and cerebellum. It can be interpreted as regional differences of disease process. In conclusion, I-123 IMP-SPECT is useful for the earlier detection of lesions in CJD. (author)

Clinical relevance of n-isopropyl-(/sup 123/I)p-iodoamphetamine (IMP) SPECT brain imaging

International Nuclear Information System (INIS)

Podreka, I.; Holl, K.; Dal Bianco, P.; Goldenberg, G.; Wimberger, D.; Auff, E.; Brucke, T.

1986-01-01

SPECT studies of the brain were performed by means of N-isopropyl-(/sup 123/I)p-iodoamphertamine and a double head rotating scintillation camera. Energy spectra showed an increase of scattered radiation proportional to the geometrical resolution of the used Tc-collimators. This is due to the higher lead content and thin septa (septum-penetration of high energy photons of /sup 123/I, scattering in the crystal) of HRES or UHRES collimators. A LEAP collimator (14 mm FWHM resolution in the reconstructed image) is the most suitable one (sufficient resolution - relatively low scatter-fraction) for /sup 123/I labeled tracers. With a multiple window technique scatter correction was performed. The width and position of the scatter windows were estimated in phantom studies. Further steps of data processing (prereconstructional filtering, analytical attenuation compensation), leading to an improvement of the final set of cross sections, are described. Clinical cases (Alzheimers, Huntingtons, Parkinson disease, Moya Moya, stroke and partial complex seizures) and stimulation (acoustic memory tasks, visual stimulations) studies in normal volunteers are presented, and results are compared with PET-data known from recent literature

Clinical evaluation of brain perfusion scintigraphy using N-isopropyl-p-( sup 123 I)-iodoamphetamine

Energy Technology Data Exchange (ETDEWEB)

Shimbo, Shin-ichiro; Yamamoto, Itsuo; Yagi, Kenji; Misaki, Takashi; Dokoh, Shigeharu (Kyoto City Hospital (Japan))

1989-10-01

The present study includes 16 patients with symptoms related to cerebrovascular insufficiency, who were randomly selected from out outpatient clinic of internal medicine. Single photon emission computed tomography (SPECT) with 111{approx}185 MBq (3{approx}5 mCi) of N-isopropyl-p-({sup 123}I)-iodoamphetamine (IMP) was performed 20 min and 3 hr after intravenous administration of the tracer, and compared to the image of conventional X-ray computed tomography (X-CT). Out of twelve cases with significant findings in X-CT, 9 showed corresponding changes in perfusion in SPECT with IMP, and the remaining 3 did not. In a patient with cerebral infarction, SPECT revealed a perfusion defect whereas her X-CT was negative, thereby proved to be useful in determining the focus of clinically suspected stroke. There were some other cases in which findings in SPECT and X-CT were discordant. From our series of scans, SPECT seemed useful in detecting responsible sites of neurological deficits in early and, occasionally, remote phases of cerebrovascular accidents, while X-CT appeared superior in finding smaller lesions. (author).

Isolated Poly(3-Hydroxybutyrate) (PHB) Granules Are Complex Bacterial Organelles Catalyzing Formation of PHB from Acetyl Coenzyme A (CoA) and Degradation of PHB to Acetyl-CoA▿

OpenAIRE

Uchino, Keiichi; Saito, Terumi; Gebauer, Birgit; Jendrossek, Dieter

2007-01-01

Poly(3-hydroxybutyrate) (PHB) granules isolated in native form (nPHB granules) from Ralstonia eutropha catalyzed formation of PHB from 14C-labeled acetyl coenzyme A (CoA) in the presence of NADPH and concomitantly released CoA, revealing that PHB biosynthetic proteins (acetoacetyl-CoA thiolase, acetoacetyl-CoA reductase, and PHB synthase) are present and active in isolated nPHB granules in vitro. nPHB granules also catalyzed thiolytic cleavage of PHB in the presence of added CoA, resulting in...

Evaluation of 59Co(n,γ)60Co, 59Co(n,2n)58Co, 59Co(nα)56Mn, for ENDF/B-IV

International Nuclear Information System (INIS)

Krieger, T.J.; Smith, A.B.; Smith, D.L.; Jenkins, J.D.

1975-01-01

The present evaluation of 59 Co (n,γ) for ENDF/B IV consists of two parts, an evaluation below 100 keV by T. J. Krieger, Brookhaven National Laboratory, and one above 100 keV by A. B. Smith and D. L. Smith, Argonne National Laboratory

Crystal Structure of N,N-bis-(3-Carbomethoxy-5-methyl-pyrazol-1-ylmethylaniline

Directory of Open Access Journals (Sweden)

Taibi Ben-Hadda

2002-09-01

Full Text Available The tripodal ligand N,N-bis-(3-carbomethoxy-5-methylpyrazol-1-ylmethyl aniline (2 has been prepared by the condensation of aniline with two equivalents of N-hydroxymethyl[3-carbomethoxy-5-methyl]pyrazole. The molecule consists of two structurally analogous 3-carbomethoxy-5-methylpyrazol-1-ylmethyl moieties, which adopt a transoidal conformation via a central aniline ring, suggesting that this tripodal ligand is highly flexible and could accommodate many metals by coordination.

Acid-Group-Content-Dependent Proton Conductivity Mechanisms at the Interlayer of Poly(N-dodecylacrylamide-co-acrylic acid) Copolymer Multilayer Nanosheet Films.

Science.gov (United States)

Sato, Takuma; Tsukamoto, Mayu; Yamamoto, Shunsuke; Mitsuishi, Masaya; Miyashita, Tokuji; Nagano, Shusaku; Matsui, Jun

2017-11-14

The effect of the content of acid groups on the proton conductivity at the interlayer of polymer-nanosheet assemblies was investigated. For that purpose, amphiphilic poly(N-dodecylacrylamide-co-acrylic acid) copolymers [p(DDA/AA)] with varying contents of AA were synthesized by free radical polymerization. Surface pressure (π)-area (A) isotherms of these copolymers indicated that stable polymer monolayers are formed at the air/water interface for AA mole fraction (n) ≤ 0.49. In all cases, a uniform dispersion of the AA groups in the polymer monolayer was observed. Subsequently, polymer monolayers were transferred onto solid substrates using the Langmuir-Blodgett (LB) technique. X-ray diffraction (XRD) analyses of the multilayer films showed strong Bragg diffraction peaks, suggesting a highly uniform lamellar structure for the multilayer films. The proton conductivity of the multilayer films parallel to the direction of the layer planes were measured by impedance spectroscopy, which revealed that the conductivity increased with increasing values of n. Activation energies for proton conduction of ∼0.3 and 0.42 eV were observed for n ≥ 0.32 and n = 0.07, respectively. Interestingly, the proton conductivity of a multilayer film with n = 0.19 did not follow the Arrhenius equation. These results were interpreted in terms of the average distance between the AA groups (l AA ), and it was concluded that, for n ≥ 0.32, an advanced 2D hydrogen bonding network was formed, while for n = 0.07, l AA is too long to form such hydrogen bonding networks. The l AA for n = 0.19 is intermediate to these extremes, resulting in the formation of hydrogen bonding networks at low temperatures, and disruption of these networks at high temperatures due to thermally induced motion. These results indicate that a high proton conductivity with low activation energy can be achieved, even under weakly acidic conditions, by arranging the acid groups at an optimal distance.

Towards a biological monitoring guidance value for acrylamide.

Science.gov (United States)

Sams, C; Jones, K; Warren, N; Cocker, J; Bell, S; Bull, P; Cain, M

2015-08-19

Acrylamide is classified as a potential human carcinogen and neurotoxicant. Biological monitoring is a useful tool for monitoring worker exposure. However, other sources of exposure to acrylamide (including cigarette smoke and diet) also need to be considered. This study has performed repeat measurements of the urinary mercapturic acids of acrylamide (AAMA) and its metabolite glycidamide (GAMA) and determined globin adducts in 20 production-plant workers at a UK acrylamide production facility. The relationship between biomarker levels and environmental monitoring data (air levels and hand washes) was investigated. Good correlations were found between all of the biomarkers (r(2)=0.86-0.91) and moderate correlations were found between the biomarkers and air levels (r(2) = 0.56-0.65). Our data show that urinary AAMA is a reliable biomarker of acrylamide exposure. Occupational hygiene data showed that acrylamide exposure at the company was well within the current UK Workplace Exposure Limit. The 90th percentile of urinary AAMA in non-smoking production-plant workers (537 μmol/mol creatinine (n = 59 samples)) is proposed as a possible biological monitoring guidance value. This 90th percentile increased to 798 μmol/mol if smokers were included (n = 72 samples). These values would be expected following an airborne exposure of less than 0.07 mg/m(3), well below the current UK workplace exposure limit of 0.3mg/m(3). Comparison of biomarker levels in non-occupationally exposed individuals suggests regional variations (between UK and Germany), possibly due to differences in diet. Crown Copyright © 2015. Published by Elsevier Ireland Ltd. All rights reserved.

System-size corrections for self-diffusion coefficients calculated from molecular dynamics simulations: The case of CO{sub 2}, n-alkanes, and poly(ethylene glycol) dimethyl ethers

Energy Technology Data Exchange (ETDEWEB)

Moultos, Othonas A.; Economou, Ioannis G. [Chemical Engineering Program, Texas A& M University at Qatar, P.O. Box 23847, Doha (Qatar); Zhang, Yong; Maginn, Edward J., E-mail: ed@nd.edu [Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Tsimpanogiannis, Ioannis N. [Chemical Engineering Program, Texas A& M University at Qatar, P.O. Box 23847, Doha (Qatar); Environmental Research Laboratory, National Center for Scientific Research “Demokritos,” 15310 Aghia Paraskevi Attikis (Greece)

2016-08-21

Molecular dynamics simulations were carried out to study the self-diffusion coefficients of CO{sub 2}, methane, propane, n-hexane, n-hexadecane, and various poly(ethylene glycol) dimethyl ethers (glymes in short, CH{sub 3}O–(CH{sub 2}CH{sub 2}O){sub n}–CH{sub 3} with n = 1, 2, 3, and 4, labeled as G1, G2, G3, and G4, respectively) at different conditions. Various system sizes were examined. The widely used Yeh and Hummer [J. Phys. Chem. B 108, 15873 (2004)] correction for the prediction of diffusion coefficient at the thermodynamic limit was applied and shown to be accurate in all cases compared to extrapolated values at infinite system size. The magnitude of correction, in all cases examined, is significant, with the smallest systems examined giving for some cases a self-diffusion coefficient approximately 15% lower than the infinite system-size extrapolated value. The results suggest that finite size corrections to computed self-diffusivities must be used in order to obtain accurate results.

Quantitative assessment of cerebral blood flow employing the Rutland method using N-isopropyl-(123I)-p-iodoamphetamine

International Nuclear Information System (INIS)

Aoki, Shigeru; Kitano, Tokio.

1992-01-01

The purpose of this study is to evaluate clinical usefulness as the quantitative assessment of the cerebral blood flow by venous sampling supersede arterial sampling using N-isopropyl-( 123 I)-p-iodoamphetamine (IMP) and single-photon emission computed tomography. The method employed Ono's report using the Rutland method. The mean value of total cerebral blood flow by arterial sampling was 388.0±79.4 (standard deviation) ml/min, and that by venous sampling was 448.5±110.3 ml/min. The value of temporal lobe, including basal ganglia where there was no evidence of neurological, electroencephalographic, and other imaging findings was 44.0±3.8 ml/100g/min using arterial sampling and 49.7±6.0 ml/100g/min using venous sampling. (n=22, mean age 57.6) The value of cases with poor peripheral circulation varied a great deal between the arterial and venous samplings. There was a good correlation between arterial and venous samplings in 76 patients without poor peripheral circulation. In conclusion, this method is available for noninvasive quantitative assessment of the cerebral blood flow in patients without poor peripheral circulation. (author)

Synthesis, characterization and photo behavior of new poly(amide-imide/montmorillonite nanocomposite containing N,N'-pyrromellitoyl-bis-L-alanine

Directory of Open Access Journals (Sweden)

M. Hajibeygi

2013-09-01

Full Text Available Two new samples of poly(amide-imide-nanocomposites were synthesized by insertion nano silicate particles in poly(amide-imide (PAI chains using a convenient solution intercalation technique. PAI as a source of polymer matrix was synthesized by the direct polycondensation reaction of N,N'-pyrromelitoyl-bis-L-alanine with 4,4'-diamino diphenyl ether in the presence of triphenyl phosphite (TPP, CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP. Morphology and structure of the resulting PAI-nanocomposite films with 5 and 10% silicate particles were characterized by FTIR spectroscopy, X-ray diffraction (XRD and scanning electron microscopy (SEM. The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposites films were investigated by using UV-Vis spectroscopy, thermogravimetric analysis (TGA and water uptake measurements.DOI: http://dx.doi.org/10.4314/bcse.v27i3.15

Poly (ethylene oxide)-block-poly (n-butyl acrylate)-blockpoly (acrylic acid) triblock terpolymers with highly asymmetric hydrophilic blocks: synthesis and aqueous solution properties

OpenAIRE

Petrov, P. (Petar); Yoncheva, K. (Krassimira); Mokreva, P. (Pavlina); Konstantinov, S. (Spiro); Irache, J.M. (Juan Manuel); Müller, A.H.E. (Axel H.E.)

2013-01-01

The synthesis and aggregation behaviour in aqueous media of novel amphiphilic poly(ethylene oxide)- block-poly(n-butyl acrylate)-block-poly(acrylic acid) (PEO–PnBA–PAA) triblock terpolymers were studied. Terpolymers composed of two highly asymmetric hydrophilic PEO (113 monomer units) and PAA (10–17 units) blocks, and a longer soft hydrophobic PnBA block (163 or 223 units) were synthesized by atom transfer radical polymerisation (ATRP) of n-butyl acrylate and tert-butyl acrylate ...

Potential of ethylenediaminedi(o-hydroxyphenylacetic acid) and N,N'-bis(hydroxybenzyl)ethylenediamine-N,N'-diacetic acid for the determination of metal ions by capillary electrophoresis.

Science.gov (United States)

Krokhin, O V; Kuzina, O V; Hoshino, H; Shpigun, O A; Yotsuyanagi, T

2000-08-25

Two aromatic polyaminocarboxylate ligands, ethylenediaminedi(o-hydroxyphenylacetic acid) (EDDHA) and N,N'-bis(hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED), were applied for the separation of transition and heavy metal ions by the ion-exchange variant of electrokinetic chromatography. EDDHA structure contains two chiral carbon centers. It makes it impossible to use the commercially available ligand. All the studied metal ions showed two peaks, which correspond to meso and rac forms of the ligand. The separation of metal-HBED chelates was performed using poly(diallyldimethylammonium) polycations in mixed acetate-hydroxide form. Simultaneous separation of nine single- and nine double-charged HBED chelates, including In(III), Ga(III), Co(II)-(III) and Mn(II)-(III) pairs demonstrated the efficiency of 40,000-400,000 theoretical plates. The separation of Co(III), Fe(III) complexes with different arrangements of donor groups and oxidation of Co(II), Mn(H), Fe(II) ions in reaction with HBED have been discussed.

UV-Induced [2+2] Grafting-To Reactions for Polymer Modification of Cellulose.

Science.gov (United States)

Conradi, Matthias; Ramakers, Gijs; Junkers, Thomas

2016-01-01

Benzaldehyde-functional cellulose paper sheets have been synthesized via tosylation of cellulose (Whatman No 5) followed by addition of p-hydroxy benzaldehyde. Via UV-induced Paterno-Büchi [2+2] cycloaddition reactions, these aldehyde functional surfaces are grafted with triallylcyanurate, trimethylolpropane allyl ether, and vinyl chloroacetate. In the following, allyl-functional polymers (poly(butyl acrylate), pBA, Mn = 6990 g mol(-1) , Đ = 1.12 and poly(N-isopropyl acrylamide), pNIPAAm, Mn = 9500 g mol(-1) , Đ = 1.16) synthesized via reversible addition fragmentation chain transfer polymerization are conjugated to the celloluse surface in a UV-induced grafting-to approach. With pBA, hydrophobic cellulose sheets are obtained (water contact angle 116°), while grafting of pNIPAAm allows for generation of "smart" surfaces, which are hydrophilic at room temperature, but that become hydrophobic when heated above the characteristic lower critical solution temperature (93° contact angle). The Paterno-Büchi reaction has been shown to be a versatile synthetic tool that also performs well in grafting-to approaches whereby its overall performance seems to be close to that of radical thiol-ene reactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Poly[ n ]catenanes: Synthesis of molecular interlocked chains

Energy Technology Data Exchange (ETDEWEB)

Wu, Qiong; Rauscher, Phillip M.; Lang, Xiaolong; Wojtecki, Rudy J.; de Pablo, Juan J.; Hore, Michael J. A.; Rowan, Stuart J.

2017-11-30

As the macromolecular version of mechanically interlocked molecules, mechanically interlocked polymers are promising candidates for the creation of sophisticated molecular machines and smart soft materials. Poly[n]catenanes, where the molecular chains consist solely of interlocked macrocycles, contain one of the highest concentrations of topological bonds. We report, herein, a synthetic approach toward this distinctive polymer architecture in high yield (similar to 75%) via efficient ring closing of rationally designed metallosupramolecular polymers. Light-scattering, mass spectrometric, and nuclear magnetic resonance characterization of fractionated samples support assignment of the high-molar mass product (number-average molar mass similar to 21.4 kilograms per mole) to a mixture of linear poly[7-26]catenanes, branched poly[13-130]catenanes, and cyclic poly[4-7]catenanes. Increased hydrodynamic radius (in solution) and glass transition temperature (in bulk materials) were observed upon metallation with Zn2+.

40 CFR 721.6540 - Acrylamide, polymers with tetraalkyl ammonium salt and polyalkyl, aminoalkyl meth-a-cryl-a-mide...

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Acrylamide, polymers with tetraalkyl... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.6540 Acrylamide, polymers... as acrylamide, polymers with tetraalkyl ammonium salt and poly-al-kyl, amino alkyl meth-a-cryl-a-mide...

Features of changes in concentration of pituitary thyroid hormone and thyroid hormones in the blood of two-month rats with experimental hypothyroidism before and after operations with N-(2-methoxybenzoyl)-O-isopropyl-α, β-dehydrothyrozine choline ester

International Nuclear Information System (INIS)

Khachatryan, T.S.; Topuzyan, V.O.

2013-01-01

The features of pituitary thyroid hormone concentration and thyroid hormones in the blood of rats with experimental hypothyroidism before and after injections of N-(2-methoxybenzoyl)-O-isopropyl-α, β-dehydrothyrozine choline ester were investigated. A sharp increase of pituitary thyroid hormone level and a sharp decrease of the level of thyroid hormones in the blood of two-month rats with hypothyroidism have been established. Under the action of N-(2-methoxybenzoyl)-O-isopropyl--α, β-dehydrothyrozine choline ester the decrease of pituitary thyroid hormone concentration and the increase of thyroid hormones level in the rats' blood have been observed and reached their values in intact animals

N-isopropyl- sup 123 I-p-iodoamphetamine uptake mechanism in the lung - is it dependent on pH, lipophilicity or pK sub a

Energy Technology Data Exchange (ETDEWEB)

Akber, S.F. (Texas Medical School, Houston, TX (United States). Dept. of Radiology)

1991-12-01

The uptake and binding mechanism of biogenic amines in the lungs has been studied extensively with no conclusive results. The competition between N-isopropyl-{sup 123}I-p-iodo amphetamines ({sup 123}I-IMP) and propranolol and {sup 123}I-IMP and ketamine, in the lungs suggest that the pK{sub a} value of the biogenic amines has a significant role to play in the mechanism of uptake and retention of biogenic amines in the lungs. (orig.).

Studies on brain blood-flow with N-isopropyl-(I-123)p-iodoamphetamine in dementia

International Nuclear Information System (INIS)

Shin, Akinori

1989-01-01

A differentiation between patients with senile dementia of Alzheimer type (SDAT) and patients with multi-infarct dementia (MID) was attempted in this paper. Twenty normal subjects, 20 SDAT and 20 MID patients were studied with single photon emission computed tomography (SPECT) using N-isopropyl-(I-123)p-iodoamphetamine ( 123 I-IMP). SPECT was started 10 minutes after the injection of 3.0 mCi 123 I-IMP. Eight anatomical regions (region of interest, ROI) were examined at the level of the basal ganglia and ten at the level of the centrum semiovale. The count ratio of each ROI to the average was calculated and tested with Student's t-test of mean differences. The ratios of right inferior frontal region and superior frontal region were significantly lower in the SDAT patients than in the normal subjects. The left superior frontal region showed lower mean ratios in SDAT patients, but the difference was not statistically significant. This study supports the suggestion that there is frontal region hypofunction in SDAT patients. SPECT with 123 I-IMP is a useful method in the non-invasive assessment of cerebral pathophysiology in dementia. (author)

Studies on brain blood-flow with N-isopropyl-(I-123)p-iodoamphetamine in dementia

Energy Technology Data Exchange (ETDEWEB)

Shin, Akinori [Osaka Medical Coll., Takatsuki (Japan)

1989-06-01

A differentiation between patients with senile dementia of Alzheimer type (SDAT) and patients with multi-infarct dementia (MID) was attempted in this paper. Twenty normal subjects, 20 SDAT and 20 MID patients were studied with single photon emission computed tomography (SPECT) using N-isopropyl-(I-123)p-iodoamphetamine ({sup 123}I-IMP). SPECT was started 10 minutes after the injection of 3.0 mCi {sup 123}I-IMP. Eight anatomical regions (region of interest, ROI) were examined at the level of the basal ganglia and ten at the level of the centrum semiovale. The count ratio of each ROI to the average was calculated and tested with Student's t-test of mean differences. The ratios of right inferior frontal region and superior frontal region were significantly lower in the SDAT patients than in the normal subjects. The left superior frontal region showed lower mean ratios in SDAT patients, but the difference was not statistically significant. This study supports the suggestion that there is frontal region hypofunction in SDAT patients. SPECT with {sup 123}I-IMP is a useful method in the non-invasive assessment of cerebral pathophysiology in dementia. (author).

Autonomic composite hydrogels by reactive printing: materials and oscillatory response.

Science.gov (United States)

Kramb, R C; Buskohl, P R; Slone, C; Smith, M L; Vaia, R A

2014-03-07

Autonomic materials are those that automatically respond to a change in environmental conditions, such as temperature or chemical composition. While such materials hold incredible potential for a wide range of uses, their implementation is limited by the small number of fully-developed material systems. To broaden the number of available systems, we have developed a post-functionalization technique where a reactive Ru catalyst ink is printed onto a non-responsive polymer substrate. Using a succinimide-amine coupling reaction, patterns are printed onto co-polymer or biomacromolecular films containing primary amine functionality, such as polyacrylamide (PAAm) or poly-N-isopropyl acrylamide (PNIPAAm) copolymerized with poly-N-(3-Aminopropyl)methacrylamide (PAPMAAm). When the films are placed in the Belousov-Zhabotinsky (BZ) solution medium, the reaction takes place only inside the printed nodes. In comparison to alternative BZ systems, where Ru-containing monomers are copolymerized with base monomers, reactive printing provides facile tuning of a range of hydrogel compositions, as well as enabling the formation of mechanically robust composite monoliths. The autonomic response of the printed nodes is similar for all matrices in the BZ solution concentrations examined, where the period of oscillation decreases in response to increasing sodium bromate or nitric acid concentration. A temperature increase reduces the period of oscillations and temperature gradients are shown to function as pace-makers, dictating the direction of the autonomic response (chemical waves).

Synthesis and property characterization of cassava starch grafted poly(acrylamide-co-(maleic acid)) superabsorbent via γ-irradiation

International Nuclear Information System (INIS)

Kiatkamjornwong, Suda; Mongkolsawat, Kanlaya; Sonsuk, Manit

2004-01-01

Graft copolymerizations of acrylamide and maleic acid onto cassava starch by a simultaneous irradiation technique using γ-rays as a initiator were carried out. Various important parameters of total dose, dose rate, monomer-to-cassava starch ratio and maleic acid content were studied. Addition of 2% ww -1 diprotic acid of maleic acid into the reaction mixture yields a saponified starch graft copolymer with a water absorption in distilled water as high as 2256g g -1 of its dried weight. The water absorption of these saponified graft copolymers insaline and buffer solutions was also measured. The water absorption depends largely on the cationic type and concentration of these solutions in terms of ionic strength. This research explains a charge transfer mechanism for graft copolymerization of maleic acid and acrylamide onto cassava starch, and describes the influential parameters that affect grafting efficiency and water absorption. (author)

Chloridrate of N-isopropyl-p-iodoamphetamine labeled with Iodine-131. Biological distribution in laboratory animals

International Nuclear Information System (INIS)

Colturato, Maria Tereza; Muramoto, Emiko; Carvalho, Olga Goncalves de

2000-01-01

The development of this work was based on a great interest from the medical class in the utilization of chloridrate of N-isopropyl-p-iodoamphetamine (IMP) labeled with 123 I, for brain perfusion evaluation. Studies were performed to optimize the labeling parameters of IMP with 131 I using nucleophilic substitution: temperature and, time reaction, ascorbic acid mass, pH and relation IMP mass/radioiodo activity, and stability of the final product. Radiochemistry purity method used showed to be efficient, quick and of easily handling for routine production. Biological distribution studies were performed in mice to determine the percent administered dose in the blood, different organs and whole body after intravenous administration of the radiopharmaceutical. The product crossed the intact blood brain barrier, allowing a follow up of further studies after the intravenous administration of the radiopharmaceutical. The principal elimination route 131 I-IMP was the urinary. Based on the results from radiochemical purity, stability and biological behavior in laboratory animals, we concluded that the studied radiopharmaceutical presents all ideal characteristics for clinical use in brain studies in nuclear medicine. (author)

Brain scintigraphy with N-isopropyl [123I] p-iodoamphetamine (123I IMP) in patients with various cerebral diseases

International Nuclear Information System (INIS)

Oshibuchi, Masao; Kanda, Teturo; Sato, Mitutaka; Miyagi, Jun; Ohtake, Hisasi; Suhara, Tetuya; Mori, Atuyoshi.

1988-01-01

Single photon emission computed tomography(SPECT) with N-isopropyl-p-[ 123 I]-iodoamphet amine(IMP) was utilized in 99 patients with various cerebral diseases and 3 healthy volunteers. By IMP SPECT, demaged area was observed as wider and faster in time than with X-ray CT or MRI. The nidus was visualized as defect of IMP in cases of AVM. In patients with subarachnoid hemorrhage, IMP SPECT was more useful for detecting of post hemorrhagic symptomatic vasospasm compared to X-ray CT or MRI. IMP SPECT was also useful to the differential diagnosis in cases of dementia. Grossed cerebellar diaschisis(CCD) was observed in 26 out of 67 cases (39 %) studied. In epilepsy the low uptake areas of IMP in the bilateral occipital lobes were observed in IMP SPECT. (author)

Facile Synthesis of Magnetic Copolymer Microspheres Based on Poly(glycidyl methacrylate-co-N-isopropylacrylamide/Fe3O4 by Suspension Photopolymerization

Directory of Open Access Journals (Sweden)

Siti Zulaikha Mazlan

2014-01-01

Full Text Available Magnetic copolymer based on poly(glycidyl methacrylate-co-N-isopropylacrylamide microspheres was prepared by 2,2-dimethoxy-2-phenylacetophenone- (DMPP- photo initiated and poly(vinyl alcohol- (PVA- stabilized single step suspension photopolymerization. The effect of chemical interaction, morphology, and thermal properties by adding 0.1% w/v Fe3O4 in the copolymer was investigated. Infrared analysis (FTIR showed that (C=C band disappeared after copolymerization, indicating that the magnetic copolymer microspheres were successfully synthesized and two important bands at 908 cm−1 and 1550 cm−1 appear. These are associated with the epoxy group stretching of GMA and secondary amide (N–H/C–H deformation vibration of NIPAAm in magnetic microspheres. The X-ray diffraction (XRD result proved the incorporation of Fe3O4 nanoparticles with copolymer microspheres as peak of Fe3O4 was observed. Morphology study revealed that magnetic copolymer exhibited uniform spheres and smoother appearance when entrapped with Fe3O4 nanoparticles. The lowest percentage of Fe3O4 nanoparticles leached from the copolymer microspheres was obtained at pH 7. Finally, thermal property of the copolymer microspheres was improved by adding a small amount of Fe3O4 nanoparticles that has been shown from the thermogram.

Study on CO2/ N2 separation: the effect of rubbery polymer coating on PVDF membrane

Science.gov (United States)

Zuwairi, M. Z.; Rahman, S. A.

2017-06-01

The emission of harmful gases such as carbon dioxide (CO2) via gas processing plant and daily human activities gave negative impacts to the environment and global inhabitant. Flat sheet asymmetric membranes were produced from homogenous solution of Poly(vinylideneflouride) (PVDF) via phase inversion method using N-methyl-2-pyrrolidone (NMP) as the solvent. While the poly ether b-amide (PEBAX) was dissolve by using of (70 ethanol and 30 water) as a solvent and and lithium chloride as a additives. The morphology and cross section of the produced membranes were observed by Scanning Electron Microscope (SEM). Then, the membranes were tested for chemical analysis to define the presence of PEBAX in the membrane by using Fourier Transform Infrared (FTIR) spectroscopy. The permeation performances of the membranes were evaluated in terms of permeability and selectivity of the membranes by using gas permeation test. Increasing the PEBAX content significantly increased the selectivity of the PVDF membrane to separate the CO2/N2 gases but decreased the amount of the gases that passed through the membrane.

Synthesis of iron nanoparticles with poly(1-vinylpyrrolidone-co-vinyl acetate) and its application to nitrate reduction

DEFF Research Database (Denmark)

Lee, Nara; Choi, Kyunghoon; Uthuppu, Basil

2014-01-01

This study aimed to synthesize dispersed and reactive nanoscale zero-valent iron (nZVI) with poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA), nontoxic and biodegradable stabilizer. The nZVI used for the experiments was prepared by reduction of ferric solution in the presence of PVP/VA with spe...

Effect of crosslinker length on the elastic and compression modulus of poly(acrylamide) nanocomposite hydrogels

International Nuclear Information System (INIS)

Zaragoza, J; Chang, A; Asuri, P

2017-01-01

Polymer hydrogelshave shown to exhibit improved properties upon the addition of nanoparticles; however, the mechanical underpinnings behind these enhancements have not been fully elucidated. Moreover, fewer studies have focused on developing an understanding of how polymer parameters affect the nanoparticle-mediated enhancements. In this study, we investigated the elastic properties of silica nanoparticle-reinforced poly(acrylamide) hydrogels synthesized using crosslinkers of various lengths. Crosslinker length positively affected the mechanical properties of hydrogels that were synthesized with or without nanoparticles. However the degree of nanoparticle enhancement was negatively correlated to crosslinker length. Our findings enable the understanding of the respective roles of nanoparticle and polymer properties on nanoparticle-mediated enhancement of hydrogels and thereby the development of next-generation nanocomposite materials. (paper)

Regional blood perfusion in childhood partial seizure using N-isopropyl-p-[I-123]iodoamphetamine and single photon emission CT

International Nuclear Information System (INIS)

Michihiro, Narumi; Kurosawa, Yumiko; Hibio, Shuichi; Ishihara, Hiroaki; Ariizumi, Motomizu

1989-01-01

Single photon emission CT (SPECT) with N-isopropyl-p-[I-123]iodoamphetamine was performed in 20 pediatric patients with partial seizure to examine regional blood perfusion. In detecting location of abnormality, SPECT and EEG were concordant in 13 patients (65%) and discordant in 4 patients (20%). In 7 patients undergoing SPECT one to 4 years after seizure onset, decreased blood perfusion corresponded to focal abnormality on EEG. In other 9 patiets in whom SPECT was performed within one year, however, location of abnormality on SPECT did not necessarily concur with that on EEG. These findings suggest that brain lesions are not focal but extensive at the early stage of partial seizure and that they are becoming focal with the mature of the central nervous system. (Namekawa, K)

CO2 capture by polymeric membranes composed of hyper-branched polymers with dense poly(oxyethylene comb and poly(amidoamine

Directory of Open Access Journals (Sweden)

Taniguchi Ikuo

2017-11-01

Full Text Available Due to CO2-philic nature of polyoxyethylene (POE, a dense POE comb structure was tethered onto PMMA backbone to develop CO2 separation membranes over N2. The resulting hyper-branched polymers displayed preferential CO2 permeation. When the polymer thin layer was formed on a high gas permeable polydimethylsiloxane (PDMS support by a spray-coating manner, the resulting thin film composite (TFC membranes displayed very high CO2 permeability. However, the CO2 selectivity, which was the permeability ratio of CO2 over N2, was moderate and lower than 50. To enhance the selectivity, poly(amidoamine (PAMAM was introduced to the hyper-branched polymers in the CO2-selective layer of the TFC membranes. The CO2 selectivity increased from 47 to 90 with increasing PAMAM content to 40 wt%, and it was drastically enhanced to 350 with PAMAM content of 50 wt%. Differential scanning calorimetry (DSC and laser microscope revealed formation of PAMAM-rich domain at the higher amine content, where CO2 could readily migrate in comparison to the other polymeric fractions.

CO2 capture by polymeric membranes composed of hyper-branched polymers with dense poly(oxyethylene) comb and poly(amidoamine)

Science.gov (United States)

Taniguchi, Ikuo; Wada, Norihisa; Kinugasa, Kae; Higa, Mitsuru

2017-11-01

Due to CO2-philic nature of polyoxyethylene (POE), a dense POE comb structure was tethered onto PMMA backbone to develop CO2 separation membranes over N2. The resulting hyper-branched polymers displayed preferential CO2 permeation. When the polymer thin layer was formed on a high gas permeable polydimethylsiloxane (PDMS) support by a spray-coating manner, the resulting thin film composite (TFC) membranes displayed very high CO2 permeability. However, the CO2 selectivity, which was the permeability ratio of CO2 over N2, was moderate and lower than 50. To enhance the selectivity, poly(amidoamine) (PAMAM) was introduced to the hyper-branched polymers in the CO2-selective layer of the TFC membranes. The CO2 selectivity increased from 47 to 90 with increasing PAMAM content to 40 wt%, and it was drastically enhanced to 350 with PAMAM content of 50 wt%. Differential scanning calorimetry (DSC) and laser microscope revealed formation of PAMAM-rich domain at the higher amine content, where CO2 could readily migrate in comparison to the other polymeric fractions.

Infraestructuras y políticas internacionales de desarrollo para gestión de los datos de investigación

Directory of Open Access Journals (Sweden)

Fabiano Couto Corrêa da Silva

2016-07-01

Full Text Available Existen enormes carencias de desarrollo tecnológico para acometer con éxito la tarea de disponer acceso, mediante la investigación y la generación de conocimiento, los datos oriundos de la investigación científica. Han surgido como una respuesta de las instituciones, en especial las académicas, repositorios que sirven para preservar y poner a disposición de su comunidad académica e investigadora, los datos de investigación que hacen parte de su patrimonio intelectual. Por lo tanto, la adopción de formatos de intercambio de datos y padronización de los mecanismos de almacenamiento son necesarias para disponer la ciencia internamente en el país y en nivel internacional. Nuestra investigación constituye un análisis de infraestructuras y políticas de desarrollo para gestión de los datos de investigación teniendo en cuenta los mecanismos adoptados para la gestión de los datos de investigación en nível internacional.

Structure and magnetization of Co4N thin film

Science.gov (United States)

Pandey, Nidhi; Gupta, Mukul; Gupta, Rachana; Rajput, Parasmani; Stahn, Jochen

2018-02-01

In this work, we studied the local structure and the magnetization of Co4N thin films deposited by a reactive dc magnetron sputtering process. The interstitial incorporation of N atoms in a fcc Co lattice is expected to expand the structure. This expansion yields interesting magnetic properties e.g. a larger magnetic moment (than Co) and a very high value of spin polarization ratio in Co4N . By optimizing the growth conditions, we prepared Co4N film having lattice parameter close to its theoretically predicted value. The N concentration was measured using secondary ion mass spectroscopy. Detailed magnetization measurements using bulk magnetization method and polarized neutron reflectivity confirm that the magnetic moment of Co in Co4N is higher than that of Co.

Dynamic studies of poly(di-n-alkyl itaconate)s

CERN Document Server

Arrighi, V; Gagliardi, S; McEwen, I J; Telling, M T F

2002-01-01

We report a preliminary dynamic study of poly(di-n-alkyl itaconate)s with varying side chain length n. QENS measurements were carried out on two backscattering spectrometers, IRIS at ISIS and IN10 at the ILL in the temperature range of 4 to 350 K. We show that molecular motion can be detected well below the polymer glass transition for all samples. It is possible to distinguish different dynamic processes. The temperature range over which these are observed is dependent on the length of the side chain, n. The intermediate scattering function, I(Q,t), was determined from the IRIS and found to obey time-temperature superposition. We show that the I(Q,t) data at different temperatures can be overlapped using the same time-scale shift factors, indicating that the relaxation process is common to all the polymers investigated. (orig.)

Synthesis, characterization and fabrication of copper nanoparticles in N-isopropylacrylamide based co-polymer microgels for degradation of p-nitrophenol

Directory of Open Access Journals (Sweden)

Farooqi Zahoor H.

2015-03-01

Full Text Available Poly(N-isopropylacrylamide-co-acrylic acid [P(NIPAM-co-AAc] microgels were synthesized by precipitation polymerization. Copper nanoparticles were successfully fabricated inside the microgels by in-situ reduction of copper ions in an aqueous medium. The microgels were characterized by Fourier Transform Infrared Spectroscopy (FT-IR and Dynamic Light Scattering (DLS. Hydrodynamic radius of P(NIPAM-co-AAc microgel particles increased with an increase in pH in aqueous medium at 25 °C. Copper-poly(N-isopropylacrylamide-co-acrylic acid [Cu-P(NIPAM-co-AAc] hybrid microgels were used as a catalyst for the reduction of 4-nitrophenol (4-NP. Effect of temperature, concentration of sodium borohydride (NaBH4 and catalyst dosage on the value of apparent rate constant (kapp for catalytic reduction of 4-NP in the presence of Cu-P(NIPAM-co-AAc hybrid microgels were investigated by UV-Vis spectrophotometry. It was found that the value of kapp for catalytic reduction of 4-NP in the presence of Cu-P(NIPAM-co-AAc hybrid microgel catalyst increased with an increase in catalyst dosage, temperature and concentration of NaBH4 in aqueous medium. The results were discussed in terms of diffusion of reactants towards catalyst surface and swelling-deswelling of hybrid microgels.

Radiation synthesis and characterization of new hydrogels based on acrylamide copolymers cross-linked with 1-allyl-2-thiourea

Energy Technology Data Exchange (ETDEWEB)

Sahiner, Nurettin [Department of Chemistry, Faculty of Science, Hacettepe University, Beytepe Campus, 0653 Ankara (Turkey); Malci, Savas [Department of Chemistry, Faculty of Science, Hacettepe University, Beytepe Campus, 0653 Ankara (Turkey); Celikbicak, Oemuer [Department of Chemistry, Faculty of Science, Hacettepe University, Beytepe Campus, 0653 Ankara (Turkey); Kantoglu, Oemer [Ankara Nuclear Research Center, Turkish Atomic Energy Authority, 06983 Ankara (Turkey); Salih, Bekir [Department of Chemistry, Faculty of Science, Hacettepe University, Beytepe Campus, 0653 Ankara (Turkey)]. E-mail: bekir@hacettepe.edu.tr

2005-10-01

Poly(acrylamide-1-allyl-2-thiourea) hydrogels, Poly(AA-AT), were synthesized by gamma irradiation using {sup 60}Co {gamma} source in different irradiation dose and at different 1-allyl-2-thiourea content in the monomer mixture. For the characterization of the hydrogels, Fourier transform infrared spectrometer (FT-IR), thermogravimetric analyzer (TGA), elemental analyzer and the swellability of the hydrogels were used. It was noted that 1-allyl-2-thiourea in the synthesized hydrogels was increased by the increasing the content of the 1-allyl-2-thiourea in the irradiation monomer mixture and increasing the radiation dose for the hydrogel synthesis. sis.

Thermosensitive membranes by radiation-induced graft polymerization of N-isopropyl acrylamide/acrylic acid on polypropylene nonwoven fabric

International Nuclear Information System (INIS)

Ikram, Saiqa; Kumari, Mamta; Gupta, Bhuvanesh

2011-01-01

Radiation-induced graft copolymerization of N-isopropylacrylamide (NIPAAm) and acrylic acid (AA) mixture was investigated on polypropylene nonwoven fabric to develop a thermosensitive material. The grafting was carried out using methanol, acetone and butanone as homopolymerization inhibitor in the reaction medium. Butanone was observed to give the maximum grafting. It was observed that the grafting is significantly influenced by the reaction conditions, such as radiation dose, monomer concentration, monomer ratio, solvent composition and reaction temperature. The degree of grafting increased as the AA and NIPAAm concentration in the reaction medium increased. The degree of grafting increased as the AA fraction in the NIPAAm/AA mixture increased. The temperature dependence of the grafting process is very much governed by the thermosensitive nature of the grafted chains right from the stage when initial grafting has taken place.

Thermosensitive membranes by radiation-induced graft polymerization of N-isopropyl acrylamide/acrylic acid on polypropylene nonwoven fabric

Energy Technology Data Exchange (ETDEWEB)

Ikram, Saiqa; Kumari, Mamta [Department of Chemistry, Jamia Millia Islamia (Central University), New Delhi-110025 (India); Gupta, Bhuvanesh, E-mail: bgupta@textile.iitd.ernet.i [Department of Textile Technology, Indian Institute of Technology, New Delhi-110016 (India)

2011-01-15

Radiation-induced graft copolymerization of N-isopropylacrylamide (NIPAAm) and acrylic acid (AA) mixture was investigated on polypropylene nonwoven fabric to develop a thermosensitive material. The grafting was carried out using methanol, acetone and butanone as homopolymerization inhibitor in the reaction medium. Butanone was observed to give the maximum grafting. It was observed that the grafting is significantly influenced by the reaction conditions, such as radiation dose, monomer concentration, monomer ratio, solvent composition and reaction temperature. The degree of grafting increased as the AA and NIPAAm concentration in the reaction medium increased. The degree of grafting increased as the AA fraction in the NIPAAm/AA mixture increased. The temperature dependence of the grafting process is very much governed by the thermosensitive nature of the grafted chains right from the stage when initial grafting has taken place.

RECUPERACIÓN DE POLI-b-HIDROXIHEXANOATO- CO-OCTANOATO SINTETIZADO POR Pseudomonas putida MEDIANTE EL USO DE DISPERSIONES H I P O C LO R I TO - C LO RO F O R M O

Directory of Open Access Journals (Sweden)

A. Espinosa-Hernández

2006-06-01

Full Text Available Se estandarizó una técnica de recuperación de poli-3-hidroxihexanoato-co-hidroxioctanoato a partir de P. putida. El método emplea dispersiones de hipoclorito de sodio-cloroformo para la digestión delmaterial celular y solubilización del polímero, respectivamente. Se evaluó el efecto de la concentración de hipoclorito, la temperatura y el tiempo sobre el porcentaje de recuperación, pureza, peso molecular y temperatura de fusión. Las mejores condiciones para recuperar este polímero fueron: hipoclorito al 5.25% (p/v a 60°C durante 1 hora. Empleando estas condiciones fue posible mantener el peso molecularpor encima del 87% con respecto al obtenido mediante extracción con cloroformo. La temperatura de fusión del polímero fue 57.7°C y 56.4°C para dos muestras al azar. La pureza del material recuperado esde 96%.

Low frequency ac conduction and dielectric relaxation in poly(N ...

Indian Academy of Sciences (India)

The ac conductivity and dielectric constant of poly(N-methyl pyrrole) thin films have been investigated in the temperature range 77–350 K and in the frequency range 102–106 Hz. The well defined loss peaks have been observed in the temperature region where measured ac conductivity approaches dc conductivity.

Ultrathin Composite Polymeric Membranes for CO2 /N2 Separation with Minimum Thickness and High CO2 Permeance.

Science.gov (United States)

Benito, Javier; Sánchez-Laínez, Javier; Zornoza, Beatriz; Martín, Santiago; Carta, Mariolino; Malpass-Evans, Richard; Téllez, Carlos; McKeown, Neil B; Coronas, Joaquín; Gascón, Ignacio

2017-10-23

The use of ultrathin films as selective layers in composite membranes offers significant advantages in gas separation for increasing productivity while reducing the membrane size and energy costs. In this contribution, composite membranes have been obtained by the successive deposition of approximately 1 nm thick monolayers of a polymer of intrinsic microporosity (PIM) on top of dense membranes of the ultra-permeable poly[1-(trimethylsilyl)-1-propyne] (PTMSP). The ultrathin PIM films (30 nm in thickness) demonstrate CO 2 permeance up to seven times higher than dense PIM membranes using only 0.04 % of the mass of PIM without a significant decrease in CO 2 /N 2 selectivity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

60Co gamma radiation effect on AlGaN//AlN/GaN HEMT devices

International Nuclear Information System (INIS)

Wang Yanping; Luo Yinhong; Wang Wei; Zhang Keying; Guo Hongxia; Guo Xiaoqiang; Wang Yuanming

2013-01-01

The testing techniques and experimental methods of the 60 Co gamma irradiation effect on AlGaN/AlN/GaN high electron mobility transistors (HEMTs) are established. The degradation of the electrical properties of the device under the actual radiation environment are analyzed theoretically, and studies of the total dose effects of gamma radiation on AlGaN/AlN/GaN HEMTs at three different radiation bias conditions are carried out. The degradation patterns of the main parameters of the AlGaN/AlN/GaN HEMTs at different doses are then investigated, and the device parameters that were sensitive to the gamma radiation induced damage and the total dose level induced device damage are obtained. (authors)

Poly(NIPAAm-co-AAm)-gold nanoshell composites for optically-triggered cancer therapeutic delivery

Science.gov (United States)

Strong, Laura Elizabeth

Cancer is currently the second leading cause of death in the United States. Although many treatment options exist, some of the most common, including radiotherapy and chemotherapy, are restricted by dose-limiting toxicities. For example, for 2-6% of patients receiving a regimen of the chemotherapeutic doxorubicin, irreversible cardiotoxicity will occur1, causing these patients to immediately cease treatment. In addition, the largest hurdle for translating novel biological therapies such as siRNA into the clinic is lack of an efficient delivery mechanism to get the therapeutic into malignant cells2. Both of these situations would benefit from a minimally invasive controlled release system that only delivers a therapeutic to the site of malignant tissue. This thesis presents work towards the creation of such a delivery platform using two novel material components: a thermally responsive poly[N-isopropylacrylamide-co-acrylamide] (NIPAAm-co-AAm) hydrogel and gold-silica nanoshells. Thermally responsive hydrogels go through a physical property transition at their lower critical solution temperature (LCST). When transitioning from below to above the LCST, the hydrogel material expels large amounts of water and absorbed molecules. This phase change can be optically triggered by embedded gold-silica nanoshells, which rapidly transfer near-infrared (NIR) light energy into heat energy due to the surface plasmon resonance phenomena. When this material is loaded with absorbed drug molecules, drug release can be externally triggered by exposure to an NIR laser. Initial characterization of this material was done using bulk hydrogel-nanoshell composites. Poly(NIPAAm-co-AAm)-nanoshell composites were synthesized via free radical polymerization. The LCST of the poly(NIPAAm-co-AAm) hydrogels was determined to be from 39-45 °C, or slightly above physiologic temperature. The material was swollen in a drug solution of either doxorubicin (a common chemotherapeutic) or a 21bp ds

Biodegradable flocculants based on polyacrylamide and poly(N,N-dimethylacrylamide) grafted amylopectin.

Science.gov (United States)

Kolya, Haradhan; Tripathy, Tridib

2014-09-01

Synthesis of amylopectin grafted polyacrylamide (AP-g-PAM) and poly(N,N-dimethylacrylamide) (AP-g-PDMA) was carried out by Ce4+ in water medium. The reaction conditions for maximum grafting was optimized by varying the reaction variables, including the concentration of monomers, ceric ammonium nitrate (CAN), amylopectin, reaction time and temperature. The graft copolymers were characterized by FTIR spectroscopy, NMR (both 1H and 13C) spectroscopy, molecular weight determination and molecular weight distribution by using size exclusion chromatography (SEC), thermal analysis (TGA), SEM studies. Biodegradation of the graft copolymers was carried out by enzyme hydrolysis. Flocculation performances of the graft copolymers were evaluated in 1.0 wt% coal and 1.0 wt% silica suspensions. A comparative study of the flocculation performances of AP-g-PDMA and AP-g-PAM was also made. It shows that the flocculation performance of AP-g-PDMA was better than that of AP-g-PAM. AP-g-PDMA performed best when compared with other commercial flocculants in the same suspensions. Copyright © 2014 Elsevier B.V. All rights reserved.

Participación política y violencia de género en América Latina

Directory of Open Access Journals (Sweden)

Laura Albaine

2014-07-01

Full Text Available Este artículo reflexiona a través del análisis de fac- tores socioculturales e institucionales sobre uno de los obstáculos más graves que condicionan la participación política de las mujeres en América Latina: El acoso y vio- lencia política en razón de género. Esta problemática es una nueva expresión que ha adoptado la violencia de gé- nero en la arena política que restringe el ejercicio de los derechos políticos de las mujeres y el derecho a vivir una vida libre de violencia. El acoso y violencia política se manifiesta más allá de los avances normativos logrados en la región orientados a generar condiciones de igualdad en términos de género en la participación política. En consecuencia, a las nor- mas que promueven el acceso de las mujeres a cargos de decisión, tales como cuotas o paridad, deben sumársele cuerpos legales que garanticen, además de sus derechos políticos, su seguridad y sus derechos humanos. AbstractThis paper focuses on a reflection and analysis of socio-cultural and institutional factors that affect wom- en’s political participation Latin America, such as gen- der-based harassment and violence. This problem is a new expression that has adopted gender-based violence in political arena, restricting not only the exercise of women’s political rights but also their right to live a life free of violence. Despite Latin American countries have enacted laws to create conditions in terms of gender equality in polit- ical participation, political harassment and violence still occurs. However, these policy actions are not enough to ensure women’s access to decision-making positions, such as quotas or parity; it must also be legal bodies to ensure, in addition to their political rights, their personal safety and human rights. 

Prediction of language and neurologic recovery after cerebral infarction with SPECT imaging using N-isopropyl-p-(I-123) iodoamphetamine

International Nuclear Information System (INIS)

Bushnell, D.L.; Gupta, S.; Mlcoch, A.G.; Barnes, W.E.

1989-01-01

Fourteen patients (10 with left-sided and 4 with right-sided cerebral infarction) were prospectively studied with single-photon emission computed tomography (SPECT) using N-isopropyl-p-(I-123) iodoamphetamine (IMP, SPECTamine) to determine its usefulness in predicting neurologic/language recovery after cerebral infarction. All neuro-SPECT imaging was performed within 30 days after infarction. Detailed assessment of neurologic and/or language recovery (after 3 months) was carried out prospectively in each patient. Patients with smaller volume IMP defects in the region of infarction demonstrated significantly better neurologic and language recovery than patients with large IMP defects. Analysis of the IMP ''redistribution'' phenomenon failed to demonstrate definitively a relationship with clinical recovery. It was concluded that the volume of the IMP defect can aid in predicting recovery potential after cerebral infarction

The Melting Behavior and Thermal Stability of Green Poly(L-lactic acid) with N, N, N, N'-Tetra(benzoyl) Ethylene Diamine Tetraacetic Acid Dihydrazide

International Nuclear Information System (INIS)

Cai, Y.; Qiang Xu, Q.; Ren, L.; Zhao, L.

2015-01-01

The thermal properties of green poly(L-lactic acid) (PLLA) with N, N, N, N'-tetra(benzoyl) ethylene diamine tetraacetic acid dihydrazide (NA) at different conditions were investigated. The melting behavior of PLLA/NA sample after isothermal crystallization at 100 degree C showed that the low-temperature melting peak shifted to high temperature with increasing of crystallization time. However, the high-temperature melting peak did not show any change. Meantime, the melting enthalpy of cold crystallization was higher than that of hot crystallization, and the difference between cold crystallization and hot crystallization increased from 0.31 J/g to 0.89 J/g with increasing of crystallization time. Heating or cooling rate affected the melting behavior of PLLA, the low-temperature and high-temperature melting peak shifted to low temperature with increasing of rate, and the ratio of melting peak area between low-temperature melting peak and high-temperature melting peak decreased. Thermal stability of PLLA/NA indicated that PLLA/NA only exhibited one decomposition stage as decomposition of PLLA. (author)

Formation of O2-methylthymine in poly(dA-dT) on methylation with N-methyl-N-nitrosourea and dimethyl sulphate. Evidence that O2-methylthymine does not miscode during DNA synthesis.

Science.gov (United States)

Saffhill, R; Abbott, P J

1978-01-01

The alternating co-polymer has been methylated with either N methyl-N-nitrosourea (MNU) or dimethyl sulphate (DMS) and the levels of the various methylated thymidines (O2-methylthymidine, 3-methylthymidine and O4-methylthymidine) measured. MNU produced all three compounds whereas DMS only produced 3-methylthymidine and O2-methylthymidine at detectable levels. These results have been combined with our earlier results concerning the misincorporation of dGMP with E. coli DNA polymerase using MNU-methylated poly(dA-dT). These results indicate that O2-methylthymidine does not miscode during DNA synthesis. PMID:353735

On d -Dimensional Lattice (co)sine n -Algebra

International Nuclear Information System (INIS)

Yao Shao-Kui; Zhang Chun-Hong; Zhao Wei-Zhong; Ding Lu; Liu Peng

2016-01-01

We present the (co)sine n-algebra which is indexed by the d-dimensional integer lattice. Due to the associative operators, this generalized (co)sine n-algebra is the higher order Lie algebra for the n even case. The particular cases are the d-dimensional lattice sine 3 and cosine 5-algebras with the special parameter values. We find that the corresponding d-dimensional lattice sine 3 and cosine 5-algebras are the Nambu 3-algebra and higher order Lie algebra, respectively. The limiting case of the d-dimensional lattice (co)sine n-algebra is also discussed. Moreover we construct the super sine n-algebra, which is the super higher order Lie algebra for the n even case. (paper)

Synthesis by ATRP of poly(ethylene-co-butylene)-block-polystyrene, poly(ethylene-co-butylene)-block-poly(4-acetoxystyrene) and its hydrolysis product poly(ethylene-co-butylene)-block-poly(hydroxystyrene)

DEFF Research Database (Denmark)

Jankova, Katja; Kops, Jørgen; Chen, Xianyi

1999-01-01

Diblock copolymers of poly(ethylene-co-butylene) and polystyrene or poly(4-acetoxystyrene) are synthesized by atom transfer radical polymerization (ATRP) using a 2-bromopropionic ester macroinitiator prepared from commercial monohydroxyl functional narrow dispersity hydrogenated polybutadiene...

Differences in micronucleus frequency and acrylamide adduct levels with hemoglobin between vegetarians and non-vegetarians.

Science.gov (United States)

Kotova, Natalia; Frostne, Cecilia; Abramsson-Zetterberg, Lilianne; Tareke, Eden; Bergman, Rolf; Haghdoost, Siamak; Paulsson, Birgit; Törnqvist, Margareta; Segerbäck, Dan; Jenssen, Dag; Grawé, Jan

2015-10-01

Nutrients and food constituents can prevent or contribute to genotoxicity. In this study, the possible influence of a vegetarian/non-vegetarian diet on genotoxic effects was investigated in 58 non-smoking healthy vegetarians (V) and non-vegetarians (NV), age 21-37 years from the Stockholm area in Sweden. Physical activity and dietary habits were similar in both groups, with the exception of the intake of meat and fish. Using flow cytometry, we determined the formation of micronuclei (MN) in transferrin-positive immature peripheral blood reticulocytes (Trf-Ret) (Total: n = 53; V: n = 27; NV: n = 26). Dietary exposure to acrylamide was measured through hemoglobin (Hb) adducts in peripheral erythrocytes (Total: n = 53; V: n = 29; NV: n = 24). Hb adducts of both acrylamide and its genotoxic metabolite glycidamide were monitored as a measure of the corresponding in vivo doses. Our data demonstrated that compared with the non-vegetarians, the vegetarians exhibited lower frequencies of MN (fMN) in the Trf-Ret (p vegetarians and non-vegetarians. Furthermore, there were no significant relationships between the adduct levels and fMN in the individuals. The ratio of the Hb adduct levels from glycidamide and acrylamide, however, showed a significant difference (p vegetarian diet might be beneficial in lowering genomic instability in healthy individuals. The measured Hb adduct levels indicate that the total intake of acrylamide does not differ between the two studied groups and does not contribute to the observed difference in fMN, although an influence of the diet on the metabolic rates of acrylamide was indicated. In addition, the observed significant difference in the background fMN in the two groups demonstrated that the MN analysis method has a sensitivity applicable to the biomonitoring of human lifestyle factors.

Effects of cigarette smoking on iodine 123 N-isopropyl-f-iodoamphetamine clearance from the lung

International Nuclear Information System (INIS)

Kato, Kunihiko; Harada, Satoshi; Takahashi, Tsuneo; Katsuragawa, Shigehiko; Yanagisawa, Toru

1991-01-01

Iodine 123 N-isopropyl-p-iodoamphetamine ( 123 I-IMP), originally developed as a brain scanning agent, is also taken up by the lung. To evaluate the effects of cigarette smoking on the kinetics of IMP in the lung, we studied 123 I-IMP clearance from the lung in 18 volunteers (8 non-smokers and 10 smokers). After the injection of 111 MBq of 123 I-IMP into the medial cubital vein, the time-activity curve for 60 min and the regional activity using 1 frame per minute and a 64x64 matrix were obtained. The 123 I-IMP clearance curve was described as follows: C(t)=A 1 e ( -k 1 t)+A 2 e ( -k 2 t)(A 1 , A 2 : intercepts, and k 1 , k 2 : slopes of the exponential components). 123 I-IMP clearance was delayed in smokers, and k 2 was smaller in smokers. Also, a correlation between k 1 , k 2 , and the number of cigarettes smoked per day was found (r=-0.65, r=-0.74, respectively, P 123 I-IMP in the lung indicate lung metabolic disorders due to cigarette smoking. (orig.)

The influence of age on N-isopropyl-p-[123I]iodoamphetamine accumulation in the human heart

International Nuclear Information System (INIS)

Nakajo, Masayuki; Nakabeppu, Yoshiaki; Iwashita, Shinji; Shinohara, Shinji

1990-01-01

Variations in heart intensity in the 30 min and 4 hr chest images of the radiolabelled lipophilic amine, N-isopropyl-p-[ 123 I]iodoamphetamine ( 123 I-IMP) were observed in 130 patients with lung diseases, aged 23 to 85 yrs. The heart intensity had a significant positive linear correlation with age (r=0.43 at 30 min, 0.66 at 4 hr). The ratio of 4 hr heart intensity to 30 min heart intensity also had a positive linear correlation (r=0.59), suggesting slower clearance of the radioactivity from the heart in older than in younger patients during this interval. Other parameters including sex, EKG findings, liver function, blood pressure, the presence of diabetes mellitus and smoking history had no relationship to heart intensity. A significant difference between heart intensities in bronchogenic carcinoma and pneumonia patient groups might be probably due to the age difference between the two groups. Therefore heart intensity in the 4 hr 123 I-IMP image may reflect certain metabolic and/or myocardial changes with aging. (author)

Acrilamida en patatas fritas: Revisión actualizada

Directory of Open Access Journals (Sweden)

Robert, Paz

2007-06-01

Full Text Available The announcement made by Swedish researches in April 2002 concerning the detection of acrylamide in many different foods, has generated a great deal of scientific publications coming from different parts of the world. The wide spectra of subjects studied includes: the kinetics of the formation and degradation of the acrylamide, the mechanisms proposed for its reduction; the analytical methods and techniques used for its determination and the experimental results obtained either with model systems or by industrial processing in the case of potato crisps and french fries.This review is focused on the state-of-the-art related to the occurrence of acrylamide in foods submitted to heat treatments in industrial operations such as frying, baking, toasting and extrusion. This review also considers the application of potato pre-treatments such as washing, blanching, and immersion in acid solutions. Special emphasis is placed on the differences between atmospheric frying and vacuum frying and on the health risks related to acrylamide intake through common foods.Con posterioridad al anuncio efectuado por investigadores suecos en Abril del año 2002 sobre la detección de acrilamida en un amplio grupo de alimentos, se han originado decenas de trabajos de investigación en diferentes partes del mundo, donde se estudian diversas temáticas de gran importancia, entre las que se pueden mencionar la cinética de la formación y degradación de la acrilamida; los mecanismos propuestos para su reducción; los métodos instrumentales empleados para su determinación y los resultados experimentales generados tanto en modelos experimentales, como en el procesamiento habitual de patatas crisps y french.En este trabajo se revisan los estudios relacionados con la formación de acrilamida en alimentos sometidos a tratamientos térmicos, en operaciones industriales básicas de fritura, horneo, tostado y extrusión. Esta revisión comprende además la aplicación de

Synthesis, characterization and rheological behavior of pH sensitive poly(acrylamide-co-acrylic acid hydrogels

Directory of Open Access Journals (Sweden)

Seddiki Nesrinne

2017-05-01

Results indicated that the strong interaction in the hydrogels resulted in the formation of a more stable copolymer. The single glass transition temperature (Tg in sample suggested that the two polymers into the hydrogel have a good miscibility. The elastic modulus (G′ and linear viscoelastic region increased with increase in PAAc concentration. The oscillation time sweep study of the hydrogels exhibited a flat G′ indicating a stable structure and good mechanical strength. In the swelling measurements, the gels exhibited appreciable water uptake and were highly sensitive to pH environment. So the poly(AAm-co-AAc hydrogel will have promising application in pharmaceutical use and in biomaterials.

Fabrication and characterization of novel multilayered structures by stereocomplexion of poly(D-lactic acid)/poly(L-lactic acid) and self-assembly of polyelectrolytes

OpenAIRE

Elena Dellacasa; Li Zhao; Gesheng Yang; Laura Pastorino; Gleb B. Sukhorukov

2016-01-01

The enantiomers poly(D-lactic acid) (PDLA) and poly(L-lactic acid) (PLLA) were alternately adsorbed directly on calcium carbonate (CaCO3) templates and on poly(styrene sulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) multilayer precursors in order to fabricate a novel layer-by-layer (LBL) assembly. A single layer of poly(L-lysine) (PLL) was used as a linker between the (PDLA/PLLA)n stereocomplex and the cores with and without the polymeric (PSS/PAH)n/PLL multilayer precursor (PEM). N...

Temperature-induced changes in polyelectrolyte films at the solid-liquid interface

International Nuclear Information System (INIS)

Steitz, R.; Leiner, V.; Tauer, K.; Khrenov, V.; Klitzing, R. v.

2002-01-01

Polyelectrolyte multilayers (film thickness 30-60 nm) were built on top of silicon substrates by layer-by-layer deposition of oppositely charged polyelectrolytes from aqueous solutions. Three kinds of films were investigated: (A) films of a homo-polyelectrolyte and a diblock copolymer with a thermosensitive poly(N-isopropyl-acrylamide) block and (B) and (C) two reference systems built solely from homo-polyelectrolytes of opposite charges. Thermal behavior and subsequent structural changes of the functionalized films against D 2 O were investigated by neutron reflectometry. All films showed irreversible annealing effects upon heating. In addition, the thermosensitive films showed a decrease in thickness at elevated temperature (>30 C) while the reference samples, composed of thermo-insensitive polyelectrolytes only, did not. (orig.)

Study of the chain microstructure effects on the resulting thermal properties of poly(L-lactide)/poly(N-isopropylacrylamide) biomedical materials

Energy Technology Data Exchange (ETDEWEB)

Lizundia, E., E-mail: erlantz.liizundia@ehu.es [Macromolecular Chemistry Research Group (LABQUIMAC), Dept. of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU) (Spain); Meaurio, E., E-mail: emiliano.meaurio@ehu.es [Department of Mining-Metallurgy and Materials Science and BERC POLYMAT, School of Engineering, University of the Basque Country (UPV/EHU) (Spain); Laza, J.M., E-mail: josemanuel.laza@ehu.es [Macromolecular Chemistry Research Group (LABQUIMAC), Dept. of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU) (Spain); Vilas, J.L., E-mail: joseluis.vilas@bcmaterials.net [Basque Center for Materials, Applications and Nanostructures (BCMaterials), Parque Tecnológico de Bizkaia, Ed. 500, Derio 48160 (Spain); León Isidro, L.M., E-mail: luismanuel.leon@ehu.es [Macromolecular Chemistry Research Group (LABQUIMAC), Dept. of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country (UPV/EHU) (Spain); Basque Center for Materials, Applications and Nanostructures (BCMaterials), Parque Tecnológico de Bizkaia, Ed. 500, Derio 48160 (Spain)

2015-05-01

The development of thermally-sensitive poly(N-isopropylacrylamide) (PNIPAAm) and biocompatible/biodegradable poly(L-lactide) (PLLA) blends offers us an efficient strategy in order to obtain materials with improved functional properties to be used in the emerging field of biomedicine. In this sense, thermal properties of PLLA and PNIPAAm have been investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and wide angle X-ray diffraction (WAXD) were conducted to shed more light on the obtained results. For a better understanding of PLLA/PNIPAAm system, both low and high molecular weight PLLA and PNIPAAm have been synthesized by ring opening polymerization and aqueous redox polymerization respectively. Obtained results are interpreted from the viewpoint of chain microstructure of each homopolymer and the ratio between two constituent materials. DSC, SEM and WAXD results show a phase separation over the entire composition range irrespectively of the molecular weight of both homopolymers. Additionally, it was found a nucleating agent behavior of low molecular weight PNIPAAm, while high molecular weight PNIPAAm hinders the crystallization of PLLA. FTIR results suggest that the strong autoassociation present in PNIPAAm plays a key role impairing the miscibility of the whole system. Thermogravimetric analysis reveals that thermodegradation process of PLLA could be continuously delayed with the addition of PNIPAAm due to the increased thermal stability of N-isopropylacrylamide in regard to L-lactide sequences. - Highlights: • Poly(L-lactide)/poly(N-isopropylacrylamide) biomedical materials are synthesized. • Results are interpreted in terms of the building block nature of each constituent. • Phase separation behavior over the entire composition range is achieved. • Strong autoassociation present in PNIPAAm impairs the miscibility of the whole blend

First Electrochemical Method of Nitrothal-Isopropyl Determination in Water Samples

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Dariusz Guziejewski

2016-01-01

Full Text Available The aim of the research was the use of square wave adsorptive stripping voltammetry (SWAdSV in conjunction with a hanging mercury drop electrode (HMDE for the determination of nitrothal-isopropyl. It was found that optimal SW technique parameters were frequency, 200 Hz; amplitude, 50 mV; and step potential, 5 mV. Accumulation time and potential were studied to select the optimal conditions in adsorptive stripping voltammetry: 45 s at 0.0 V, respectively. The calibration curve (SWSV was linear in the nitrothal-isopropyl concentration range from 2.0 × 10−7 to 2.0 × 10−6 mol L−1 with detection limit of 3.46 × 10−8 mol L−1. The repeatability of the method was determined at a nitrothal-isopropyl concentration level equal to 6.0 × 10−7 mol L−1 and expressed as RSD = 5.5% (n=6. The proposed method was successfully validated by studying the recovery of nitrothal-isopropyl in spiked environmental samples.

The involvement of poly(ADP-ribose) polymerase in the degradation of NAD caused by γ-radiation and N-methyl-N-nitrosourea

International Nuclear Information System (INIS)

Skidmore, C.J.; Davies, M.I.; Goodwin, P.M.; Halldorsson, H.; Lewis, P.J.; Shall, S.; Zia'ee, A.

1979-01-01

Both N-methyl-N-nitrosourea and γ-radiation lower cellular NAD in mouse leukaemia cells (L1210) in a dose-dependent way. The minimum NAD level is reached 2 h after a brief exposure to N-methyl-N-nitrosourea, but within 15 min of γ-irradiation. The cells remain metabolically active; they are able to recover their control NAD levels and are impermeable to trypan blue. Several inhibitors of poly(ADP-ribose) polymerase inhibit the drop in cellular NAD caused by these two agents: 2 mM 5-methylnicotinamide, 1 mM theophylline or 1 mM theobromine inhibit the effect of N-methyl-N-nitrosourea on cellular NAD level; 200 μM thymidine, 500 μM 5-methylnicotinaminde, 500 μM thephylline and 500 μM theobromine prevent the lowering of cellular NAD by γ-irradiation. The extent to which the drop in cellular NAD is inhibited is dependent on both the concentration of cytotoxic agent and of polymerase inhibitor. Caffeine will inhibit the drop in NAD but only at 10 mM, while nicotonic acid is ineffictive even at this dose. The activity of poly(ADP-ribose) polymerase is permeabilized cells immediately after γ-radiation increases with dose up to 12 krad, giving a maximal 3.4-fold stimulation of the enzyme activity, whereas the degradation of NAD under conditions optimal for NAD glycohydrolase does not change. The activity of the polymerase shows a close temporal correlation with the NAD drop following both γ-radiation and N-methyl-N-nitrosourea. The enzyme activity is maximal when the NAD content. (orig./AJ) 891 AJ/orig.- 892 HIS [de

Entrappment of alkaline protease and β-galactosidase in radiation stitched together poly-N-vinylcaprolactam

International Nuclear Information System (INIS)

Davidenko, T.I.; Kravchenko, I.A.

1996-01-01

The gel formations by poly-N-vinylcaprolactam upon its γ-irradiation by the 20-25 kGy dose as a results of partial polymer stitching together is shown, which is confirmed by the CD-and thermogravimetric data. By the alkaline protease and β-galactosidase entrapment in poly-N- vinylcaprolactam stitched together by γ-irradiation, the active preparations are obtained with 90-98 % and 30-35 % activity retained for alkaline protease and β-galactosidase, respectively. The increased stability of alkaline protease at acidic pH values and higher temperature was noted, and for β-galactosidase - the possibility of repeated use of the obtained preparation for lactose hydrolysis

Solid polymer/salt electrolytes based on linear poly((N-2-cyanoethyl)ethylenimine)

International Nuclear Information System (INIS)

Erickson, M.; Frech, R.; Glatzhofer, D.T.

2003-01-01

There has been growing interest in the structure, properties, ionic association, and conductivity in poly(acrylonitrile) (PAN)/salt systems and its structural analogues. We have developed a simple procedure to cyanoethylate the nitrogen atoms (>95% by 1 H-NMR) of linear poly(ethylenimine) (PEI) to form poly((N-2-cyanoethyl)ethylenimine) (PCEEI). IR studies indicate that, like PAN, a second nitrile stretching band develops for PCEEI on addition of LiTf, indicating coordination of nitrile groups to Li cations. However, spectroscopic data on the triflate ions indirectly suggest that, unlike PAN/LiTf systems, PCEEI systems contain significant proportions of 'free' Li cations at high LiTf concentrations. Initial results indicate the RT ionic conductivity in the PCEEI systems is on the order of 10 -8 S cm -1 at a composition of N:Li=6:1 and was found to be largely independent of LiTf concentration over a range of sample concentrations. The nature of the relative concentrations of ionic species of LiTf in PCEEI was determined with infrared spectroscopy. Results of room temperature and variable temperature complex impedance measurements are presented

Poly(acrylamide) functionalized chitosan: An efficient adsorbent for azo dyes from aqueous solutions

International Nuclear Information System (INIS)

Singh, Vandana; Sharma, Ajit Kumar; Sanghi, Rashmi

2009-01-01

In the present communication we report on the optimization of persulfate/ascorbic acid initiated synthesis of chitosan-graft-poly(acrylamide) (Ch-g-PAM) and its application in the removal of azo dyes. The optimum yield of the copolymer was obtained using 16 x 10 -2 M acrylamide, 3.0 x 10 -2 M ascorbic acid, 2.4 x 10 -3 M K 2 S 2 O 8 and 0.1 g chitosan in 25 mL of 5% aqueous formic acid at 45 ± 0.2 o C. Ch-g-PAM remained water insoluble even under highly acidic conditions and could efficiently remove Remazol violet and Procion yellow dyes from the aqueous solutions over a pH range of 3-8 in contrast to chitosan (Ch) which showed pH dependent adsorption. The adsorption data of the Ch-g-PAM and Ch for both the dyes were modeled by Langmuir and Freundlich isotherms where the data fitted better to Langmuir isotherms. To understand the adsorption behavior of Ch-g-PAM, adsorption of Remazol violet on to the copolymer was optimized and the kinetic and thermodynamic studies were carried out taking Ch as reference. Both Ch-g-PAM and Ch followed pseudo-second-order adsorption kinetics. The thermodynamic study revealed a positive heat of adsorption (ΔH o ), a positive ΔS o and a negative ΔG o , indicating spontaneous and endothermic nature of the adsorption of RV dye on to the Ch-g-PAM. The Ch-g-PAM was found to be very efficient in removing color from real industrial wastewater as well, though the interfering ions present in the wastewater slightly hindered its adsorption capacity. The data from regeneration efficiencies for ten cycles evidenced the high reusability of the copolymer in the treatment of waste water laden with even high concentrations of dye.

Block copolymers of poly(l-lactide) and poly(e-caprolactone) or poly(ethylene glycol) prepared by reactive extrusion

NARCIS (Netherlands)

Stevels, W.M.; Bernard, A.; van de Witte, P.; van de Witte, P.; Dijkstra, Pieter J.; Feijen, Jan

1996-01-01

Blends of poly(L-lactide) (PLLA) and poly(-caprolactone) (PCL) were prepared in a co-rotating twin screw miniextruder (40 rpm, 200°). It was attempted to prepare multiblock copolymers by allowing a controlled number of transesterification reactions. Various cat-alysts (n-Bu3SnOMe, Sn(Oct)2,

Synthesis and application of solar cells of poly (3-decylthiophene/N/titanium dioxide hybrid

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2011-05-01

Full Text Available An organic-inorganic nanocomposite material of poly (3-decylthiophene and titanium dioxide doped with N (P3DT/N/TiO2 were synthesized. Structures were characterized using X-ray diffraction (XRD, infrared spectroscopy (IR, transmission electron microscopy (TEM, and X-ray photoelectron spectroscopy (XPS. Optical and electrochemical properties were determined using UV-visible spectroscopy, fluorescence spectroscopy, and cyclic voltammetry. These tests indicated that P3DT/N/TiO2 was a new p-n semiconductor photoelectric material, and the solar cell prepared with P3DT/N/TiO2 performed well.

Supercritical CO2 drying of poly(methyl methacrylate) photoresist for deep x-ray lithography: a brief note

Science.gov (United States)

Shukla, Rahul; Abhinandan, Lala; Sharma, Shivdutt

2017-07-01

Poly(methyl methacrylate) (PMMA) is an extensively used positive photoresist for deep x-ray lithography. The post-development release of the microstructures of PMMA becomes very critical for high aspect ratio fragile and freestanding microstructures. Release of high aspect ratio comb-drive microstructure of PMMA made by one-step x-ray lithography (OXL) is studied. The effect of low-surface tension Isopropyl alcohol (IPA) over water is investigated for release of the high aspect ratio microstructures using conventional and supercritical (SC) CO2 drying. The results of conventional drying are also compared for the samples released or dried in both in-house developed and commercial SC CO2 dryer. It is found that in all cases the microstructures of PMMA are permanently deformed and damaged while using SC CO2 for drying. For free-standing high aspect ratio microstructures of PMMA made by OXL, it is advised to use low-surface tension IPA over DI water. However, this brings a limitation on the design of the microstructure.

Rational design, efficient syntheses and biological evaluation of N,N '-symmetrically bis-substituted butylimidazole analogs as a new class of potent Angiotensin II receptor blockers

Czech Academy of Sciences Publication Activity Database

Agelis, G.; Resvani, A.; Koukoulitsa, C.; Tůmová, Tereza; Slaninová, Jiřina; Kalavrizioti, D.; Spyridaki, K.; Afantitis, A.; Melagraki, G.; Siafaka, A.; Gkini, E.; Megariotis, G.; Grdadolnik, S. G.; Papadopoulos, M. G.; Vlahakos, D.; Maragoudakis, M.; Liapakis, G.; Mavromoustakos, T.; Matsoukas, J.

2013-01-01

Roč. 62, Apr (2013), s. 352-370 ISSN 0223-5234 Institutional support: RVO:61388963 Keywords : AT1 receptor blockers * N,N '-Bis-alkylated butylimidazole analogs * synthesis * Wittig reaction * hydroxymethylation * structure elucidation Subject RIV: CC - Organic Chemistry Impact factor: 3.432, year: 2013

Demonstration and quantitation of pharmacological inhibition of pulmonary uptake of N-isopropyl-123I-p-Iodoamphetamine by propanolol

International Nuclear Information System (INIS)

Akber, S.F.

1989-01-01

The first-pass pulmonary extraction values of N-Isopropyl- 123 I-p-Iodoamphetamine ( 123 I-IMP) in pretreated dogs decreases from 90 to 62% as the amount of propranolol increases from 0 to 20 mg. The first-pass pulmonary extraction values of 123 I-IMP in dogs with a simultaneous bolus injection of propranolol decreases from 90 to 62% as the amount of propranolol increases from 0 to 10 mg. The pulmonary extraction of 123 I-IMP with a simultaneous bolus injection of ketamine and 123 I-IMP decreases from 90 to 64% as the ketamine dose increases from 0 to 100 mg. These results suggest that the pulmonary uptake of 123 I-IMP may be at least partially mediated by receptors. They also indicate that endothelial metabolic cell function may be a useful index of early lung pathology. Furthermore, studies of the degree of lung uptake may be a sensitive index of pathologic states in which alterations of amine binding sites have occurred. (orig.) [de

Successful Treatment of Acute Lethal Dose of Acrylamide Poisoning

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Ali Banagozar Mohammadi

2015-03-01

Full Text Available Background: Acrylamide (C3H5NO is a vinyl monomer. This water-soluble crystalline solid is a colorless, odorless agent which is used in scientific laboratories and some industries. Acrylamide has cellular oxidative effects. Acute or chronic poisoning with this agent happens as a result of skin, respiratory, or oral contacts. Clinical manifestations depend on the dose, duration, and frequency of contact. Management of these patients consists of conservative and palliative therapies to reduce the oxidative effects. Case: The case was a 29-year-old girl with a Master of Sciences degree in genetics who worked in a university research center with previous history of depression. She had ingested 100cc of 30% Acrylamide solution for intentional suicide attempt. The patient was successfully managed using N-acetyl cysteine, vitamin C, and melatonin. Conclusion: Early diagnosis and appropriate treatment with recommended agents together with supportive therapies can save the life of patients exposed to potentially lethal doses of acrylamide, although intentional or accidental.

Evaluation of cross-section data from threshold to 40-60 MeV for specific neutron reactions important for neutron dosimetry applications. Part 1: Evaluation of the excitation functions for the 27Al(n,α)24Na, 55Mn(n,2n)54Mn, 59Co(n,p)59Fe, 59Co(n,2n)58m+gCo and 90Zr(n,2n)89m+gZr reactions

International Nuclear Information System (INIS)

Zolotarev, K.I.

2009-04-01

Evaluations of cross sections and their associated covariance matrices have been carried out for five dosimetry reactions: - excitation functions were re-evaluated for the 27 Al(n,α) 24 Na, 55 Mn(n,2n) 54 Mn and 90 Zr(n,2n) 89m+g Zr reactions over the neutron energy range from threshold to 40 MeV; - excitation functions were re-evaluated for the 59 Co(n,p) 59 Fe and 59 Co(n,2n) 58m+g Co reactions over the neutron energy range from threshold to 60 MeV. Uncertainties in the cross sections for all of those reactions were also derived in the form of relative covariance matrices. Benchmark calculations performed for 235 U thermal fission and 252 Cf spontaneous fission neutron spectra show that the integral cross sections calculated from the newly evaluated excitation functions exhibit improved agreement with related experimental data when compared with the equivalent data from the IRDF-2002 library. (author)

Diagnosis of Joseph disease by means of N-isopropyl-p-[123I]iodoamphetamine (IMP) SPECT

International Nuclear Information System (INIS)

Takahashi, Naoya; Nishihara, Mamiko; Odano, Ikuo; Sakai, Kunio; Yuasa, Tatsuhiko.

1993-01-01

Using N-isopropyl-p-[ 123 I]iodoamphetamine (IMP) and single-photon-emission computed tomography (SPECT), we studied the regional cerebral blood flow (rCBF) in 4 Japanese patients who had been clinically diagnosed as having Joseph disease. This is the first report of rCBF measurement by means of [ 123 I]-IMP SPECT in patients with Joseph disease. Cerebellar atrophy was evaluated by means of a 5-rating scale as defined by X-ray computed tomography (X-CT). As compared with 10 normal controls (mean cerebellar CBF±SD: 66.9±6.6 ml/100 g/min), the regional CBF of the patients with Joseph disease was found to decrease significantly in the cerebellum (mean±SD: 52.8±5.3 ml/100 g/min). However, no significant relationship was found between the decrease in rCBF in the cerebellum and the degree of cerebellar atrophy as shown by X-CT. The regional CBF in the cerebellum decreased little in one patient who had severe cerebellar atrophy or in two who showed moderate atrophy. [ 123 I]-IMP SPECT demonstrates the pathological and metabolic changes in the cerebellum that do not appear on X-CT or MRI. IMP SPECT is thus shown to be useful for the diagnosis of patients with Joseph disease. (author)

Poly (N-isopropylacrylamide Microgel-Based Optical Devices for Sensing and Biosensing

Directory of Open Access Journals (Sweden)

Molla R. Islam

2014-05-01

Full Text Available Responsive polymer-based materials have found numerous applications due to their ease of synthesis and the variety of stimuli that they can be made responsive to. In this review, we highlight the group’s efforts utilizing thermoresponsive poly (N-isopropylacrylamide (pNIPAm microgel-based optical devices for various sensing and biosensing applications.

Efficient and environmental-friendly dehydration of fructose to 5-hydroxymethyl-2-furfural in water under high pressure of CO2

NARCIS (Netherlands)

Motokucho, Suguru; Morikawa, Hiroshi; Nakatani, Hisayuki; Noordover, Bart A.J.

2016-01-01

To develop reaction systems of chemical conversion of biomass, fructose was heated in an aqueous medium under pressurized CO2, which caused in situ generation of carbonic acid. It gave 5-hydroxymethyl-2-furfural (HMF) as a dehydration product in good yields. The maximum yield of HMF was 92% in the

Gum ghatti based novel electrically conductive biomaterials: A study of conductivity and surface morphology

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S. Kalia

2014-04-01

Full Text Available Gum ghatti-cl-poly(acrylamide-aniline interpenetrating network (IPN was synthesized by a two-step aqueous polymerization method, in which aniline monomer was absorbed into the network of gum ghatti-cl-poly(acrylamide and followed by a polymerization reaction between aniline monomers. Initially, semi-IPN based on acrylamide and gum ghatti was prepared by free-radical copolymerization in aqueous media with optimized process parameters, using N,N'-methylenebis-acrylamide, as cross-linker and ammonium persulfate, as an initiator system. Optimum reaction conditions affording maximum percentage swelling were: solvent [mL] =12, Acrylamide (AAm [mol•L–1] = 1.971, Ammonium peroxydisulfate (APS [mol•L–1] = 0.131•10–1, N,N'-methylene-bis-acrylamide (MBA [mol•L–1] = 0.162•10–1, reaction time [min] = 210, temperature [°C] = 100 and pH = 7.0. The resulting IPN was doped with different protonic acids. The effect of the doping has been investigated on the conductivity and surface morphology of the IPN hydrogel. The maximum conductivity was observed with 1.5N HClO4 concentration. The morphological, structural and electrical properties of the candidate polymers were studied using scanning electron micrscopy (SEM, Fourier transform infrared spectroscopy FTIR and two-probe method, respectively.

Thermodynamic stability and guest distribution of CH4/N2/CO2 mixed hydrates for methane hydrate production using N2/CO2 injection

International Nuclear Information System (INIS)

Lim, Dongwook; Ro, Hyeyoon; Seo, Yongwon; Seo, Young-ju; Lee, Joo Yong; Kim, Se-Joon; Lee, Jaehyoung; Lee, Huen

2017-01-01

Highlights: • We examine the thermodynamic stability and guest distribution of CH 4 /N 2 /CO 2 mixed hydrates. • Phase equilibria of the CH 4 /N 2 /CO 2 mixed hydrates were measured to determine the thermodynamic stability. • The N 2 /CO 2 ratio of the hydrate phase is almost constant despite the enrichment of CO 2 in the hydrate phase. • 13 C NMR results indicate the preferential occupation of N 2 and CO 2 in the small and large cages of sI hydrates, respectively. - Abstract: In this study, thermodynamic stability and cage occupation behavior in the CH 4 – CO 2 replacement, which occurs in natural gas hydrate reservoirs by injecting flue gas, were investigated with a primary focus on phase equilibria and composition analysis. The phase equilibria of CH 4 /N 2 /CO 2 mixed hydrates with various compositions were measured to determine the thermodynamic stability of gas hydrate deposits replaced by N 2 /CO 2 gas mixtures. The fractional experimental pressure differences (Δp/p) with respect to the CSMGem predictions were found to range from −0.11 to −0.02. The composition analysis for various feed gas mixtures with a fixed N 2 /CO 2 ratio (4.0) shows that CO 2 is enriched in the hydrate phase, and the N 2 /CO 2 ratio in the hydrate phase is independent of the feed CH 4 fractions. Moreover, 13 C NMR measurements indicate that N 2 molecules preferentially occupy the small 5 12 cages of sI hydrates while the CO 2 molecules preferentially occupy the large 5 12 6 2 cages, resulting in an almost constant area ratio of CH 4 molecules in the large to small cages of the CH 4 /N 2 /CO 2 mixed hydrates. The overall experimental results provide a better understanding of stability conditions and guest distributions in natural gas hydrate deposits during CH 4 – flue gas replacement.

Synthesis and characterization of poly[1-(N,N-bis-carboxymethyl)amino-3-allylglycerol-co-dimethylacrylamide] grafted to magnetic nano-particles for extraction and determination of letrozole in biological and pharmaceutical samples.

Science.gov (United States)

Ahmad Panahi, Homayon; Soltani, Elham Reza; Moniri, Elham; Tamadon, Atefeh

2013-12-15

In this paper, a new method is reported for the surface grafting of poly[1-(N,N-bis-carboxymethyl)amino-3-allylglycerol-co-dimethylacrylamide] onto magnetic nano-particles modified by 3-mercaptopropyltrimethoxysilane. The grafted nano-sorbent was characterized by Fourier transform infrared spectroscopy, elemental analysis, thermogravimetric analysis, and scanning electron microscopy. Agglomerated nano-particles with multi-pores were used for extraction and determination of trace letrozole in human biological fluids and pharmaceutical samples. The profile of the letrozole uptake by the magnetic nano-sorbent reflected good accessibility of the active sites in the grafted polymer. Scatchard analysis revealed that the sorption capacity of the functionalized nano-sorbent was 6.27 µmol g(-1) at an optimum pH of 4. The equilibrium adsorption data of letrozole by grafted magnetic nano-sorbent were analyzed by Langmuir, Freundlich, Temkin and Redlich-Peterson models. Conformation of the experimental data in the Langmuir isotherm model indicated the homogeneous binding site of functional polymer-grafted magnetic nano-sorbent surface. Nearly 89% of letrozole was released in simulated gastric fluid, pH 1.2, in 2h and 79% in simulated intestinal fluid, pH 7.4, in 30 h. These results show the utility of the letrozole loaded- polymer grafted magnetite nano-particles for enteric drug delivery. © 2013 Elsevier B.V. All rights reserved.

Double-radionuclide autoradiographic method using N-isopropyl-iodoamphetamine for sequential measurements of local cerebral blood flow

International Nuclear Information System (INIS)

Obrenovitch, T.P.; Clayton, C.B.; Strong, A.J.

1987-01-01

A double-radionuclide autoradiographic method has been assessed for sequential determinations of local CBF (LCBF). It is based on two successive intravascular injections of N-isopropyl-p-iodoamphetamine (IMP) labelled with different radionuclides, whose concentrations can later be differentiated in the same tissue section using double-radionuclide autoradiography. Previous studies suggested that the distribution of IMP, up to 30 min after its administration, still represents LCBFs. Our data indicate that, provided the tracer is injected directly into the left ventricle, there is little back diffusion from normal brain to blood under physiological conditions for at least 35 min following the tracer injection and an injection of unlabelled IMP, in a dose larger than that used for blood flow determination, does not displace any labelled IMP previously taken up by the brain, nor does it displace any labelled IMP previously accumulated in the lung that would lead to secondary brain uptake. On the basis of these results, we conclude that sequential autoradiographic determinations of LCBF using IMP labelled with different radionuclides is possible. This is a promising experimental method for the simultaneous investigation of changes in LCBF in several CNS structures

Fundamental Flotation Behaviors of Chalcopyrite and Galena Using O-Isopropyl-N-Ethyl Thionocarbamate as a Collector

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Yongjie Bu

2018-03-01

Full Text Available Copper and lead are two important and widely used metals in industry. Chalcopyrite (CuFeS2 is associated with galena (PbS in ore, and it has been a research hotspot in separating galena from chalcopyrite by flotation. In this study, the flotation behaviors of chalcopyrite and galena were studied through flotation tests, adsorption measurements, solution chemistry calculation, Fourier transform infrared spectroscopy (FTIR and molecular dynamics (MD simulations. The results show that the floatability of chalcopyrite is better than that of galena in the presence of O-isopropyl-N-ethyl thionocarbamate (IPETC, and the recovery difference between chalcopyrite and galena is about 20% when IPETC is 7 × 10−4 mol/L at pH 9.5, while the floatability difference between the two minerals is significant. Competitive adsorption of OH− and IPETC on mineral surfaces leads to lower floatability of galena than that of chalcopyrite. IPETC is able to remove the hydration layer on mineral surfaces and then adsorb on active sites. The floatability of minerals is enhanced with the increase of their hydrophobicity. This study provides a reference to separate galena from chalcopyrite.

Polytetrafluorethylene (PTFE) copolymerization with N-N'- dimethyl acrylamide (DMAA) using gamma radiation

International Nuclear Information System (INIS)

Queiroz, A.A. de; Higa, O.Z.

1990-01-01

The copolymerization of N-N'-dimethylacrylamide monomer with polytetrafluorethylene was made using an insert technique by gamma irradiation. The polimeric surface was characterized by electron microscopy. (author) [pt

Síntese e caracterização de hidrogéis compósitos a partir de copolímeros acrilamida-acrilato e caulim: efeito da constituição de diferentes caulins do nordeste brasileiro Synthesis and characterization of poly (acrylamide-co-acrylate and kaolin hydrogel composites: effect of the constitution of different kaolins from northeastern Brazil

Directory of Open Access Journals (Sweden)

Carlos W. de Q. Brito

2013-01-01

Full Text Available Superabsorbent hydrogels based on poly (acrylamide-co-acrylate and different kaolins, were prepared by free-radical aqueous copolymerization. FTIR and WAXS techniques were employed for characterization of a series of hydrogels, obtained by varying the percentage of clay, crosslinking and constitution of kaolin. The water absorbency at equilibrium (Weq decreased with increasing clay content and the amount of crosslinking agent. Superabsorbent hydrogel (Weq > 1084 g H2O/g gel was obtained as 10 wt% of white kaolin and 0.05 mol% of crosslinking agent were used. The hydrogel proved sensitive to pH variation and the presence of salts.

Investigation of variations in the acrylamide and N(ε) -(carboxymethyl) lysine contents in cookies during baking.

Science.gov (United States)

Cheng, Lu; Jin, Cheng; Zhang, Ying

2014-05-01

Baking processing is indispensable to determine special sensory prosperities of cookies and induces the formation of some beneficial components such as antioxidants. However, the formation of some Maillard reaction-derived chemical hazards, such as acrylamide (AA) and N(ε) -(carboxymethyl) lysine (CML) in cookies is also a significant consequence of baking processing from a food safety standpoint. This study investigated the effects of baking conditions on the formation of AA and CML, as well as the antioxidant activity (AOA) of cookies. Cookies were baked at various baking temperatures (155 to 230 °C) and times (1.5 to 31 min). AA and CML contents were determined by ultra-performance liquid chromatography-tandem mass spectrometry, respectively. The highest level of AA was obtained in the cookies baked at 155 °C/21 min and 205 °C/11 min (328.93 ± 3.10 μg/kg and 329.29 ± 5.29 μg/kg), while the highest level of CML was obtained in the cookies baked at 230 °C/1.5 min (118.05 ± 0.21 mg/kg). AA was prone to form at relatively low temperature range (155 to 205 °C), however, CML at relatively high temperature range (205 to 230 °C). The CML content was much higher than the AA content in the same set of cookies, by about 2 to 3 orders of magnitude. The AOA of cookies increased at more severe baking conditions. According to the AA and CML content, AOA and sensory properties of cookies, the temperature-time regime of 180 °C/16 min might be a compromised selection. However, only optimizing the baking condition was not enough for manufacture of high-quality cookies. Cookies, a kind of widely consumed bakery products in the world, contain some potentially harmful compounds, like acrylamide (AA) and N(ε) -(carboxymethyl) lysine (CML). AA in cookies has led to public health concern and several research efforts. But CML, another Maillard reaction-derived chemical hazard, has been neglected so far, even though its content is much higher than that of AA in cookies. The

The evaluation of temperature and pH influences on equilibrium swelling of poly(n-isopropylacrylamide-co-acrylic acid hydrogels

Directory of Open Access Journals (Sweden)

Zdravković Aleksandar S.

2017-01-01

Full Text Available Hydrogels are synthesized by the method of radical polymerization of monomers: N-isopropylacrylamide (NIPAM and acrylic acid (AA. Characterization of poly(N-isopropylacrylamide- co-acrylic acid hydrogels, p(NIPAM/AA, has been performed by Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD and by determination of the swelling behaviour in aqueous solutions at different temperatures (25, 31 and 37°C and pH values (2.2, 4.5, 6 and 6.8. After lyophilisation in the solution at pH 6 and temperature of 25°C, p(NIPAM/AA hydrogels have rapidly reached equilibrium degree of swelling, αe, in comparison to non-lyophilized samples. The mechanism of solvent transport within matrix in lyophilized samples corresponds to less Fickian diffusion, whereas Super case II diffusion is characteristic for non-lyophilized samples. p(NIPAM/AA hydrogel with 1.5 mol% of ethylene glycol dimethacrylate (EGDM at the temperature of 25°C and pH 6.8, has reached the highest swelling equilibrium degree, αe = 259.8. The results of swelling studies have shown that p(NIPAM/AA hydrogels can be classified as superabsorbent polymers (SAPs. For the evaluation of pH and temperature influences on synthesized hydrogels swelling, a full three-level experimental design has been used. Two-factor interaction model (2FI is the most optimal model of a full three-level experimental design for representing the swelling equilibrium degree of p(NIPAM/AA hydrogels as a function of investigated parameters, i.e., temperature and pH. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR-34012

Analysis and assessment for the intrapulmonary kinetics of N-isopropyl-I-123-p-iodoamphetamine (IMP) in diffuse respiratory diseases

International Nuclear Information System (INIS)

Fujishima, Seitaro

1992-01-01

We investigated intrapulmonary kinetics of N-isopropyl-I-123-p-iodoamphetamine (IMP) in patients with diffuse respiratory diseases. Subjects studied were 4 healthy nonsmoking controls (age≥40), 3 young healthy nonsmokers (age 1 ) was smaller than that to the slow compartment (A 2 ). There was no difference in the A 1 to A 2 ratio among the groups. We then analyzed the slopes of the fast and slow compartments (k 1 , k 2 ). There was no difference in k 1 among the groups. On the other hand, k 2 was larger in young healthy nonsmokers and smaller in healthy smokers, the patients with IPF, sarcoidosis and CPE than k 2 in nonsmoking controls. Furthermore, k 2 decreased in inverse proportion to age. We concluded that k 2 could be a valuable index to detect changes of IMP, a lipophilic amine, metabolism in the lungs. (author)

Chemical modification of polyaniline by N-grafting of polystyrenic chains synthesized via nitroxide-mediated polymerization

International Nuclear Information System (INIS)

Hatamzadeh, Maryam; Mahyar, Ali; Jaymand, Mehdi

2012-01-01

This study aims to explore an effective route for the preparation of conductive N-substituted polyaniline (PANI) by the incorporation of brominated poly(styrene-co-p-methylstyrene) onto the emeraldine form of polyaniline. For this purpose, at first, poly(styrene-co-p-methylstyrene) was synthesized via nitroxide-mediated polymerization (NMP), and then, N-bromosuccinimide was used as brominating agent to obtain a copolymer with bromine. Thereafter, deprotonated polyaniline was reacted with brominated poly(styrene-co-p-methylstyrene) to prepare the poly(styrene-co-p-methylstyrene)-graft-polyaniline [(PSt-co-PMSt)-g-PANI] terpolymer through N-grafting reaction. The terpolymer was characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Optical properties of (PSt-co-PMSt)-g-PANI in the undoped and doped states were obtained by ultraviolet-visible spectroscopy (UV-Vis), and electrical conductivity at room temperature was measured using samples in which the conductive materials was sandwiched between two Ni electrodes. Moreover, electroactivity of the synthesized terpolymer was verified under cyclic voltammetric conditions on the surface of the working glassy carbon electrode (GCE). The solubility of (PSt-co-PMSt)-g-PANI terpolymer was examined in common organic solvents, such as, tetrahydrofuran (THF), chloroform and xylene. (author)

Greenhouse Gas (CO2 AND N2O Emissions from Soils: A Review Emisión de Gases invernadero (CO2 y N2O desde Suelos

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Cristina Muñoz

2010-09-01

Full Text Available In agricultural activities, the main greenhouse gases (GHG are those related to C and N global cycles. The impact of agriculture on GHG emissions has become a key issue, especially when considering that natural C and N cycles are influenced by agricultural development. This review focuses on CO2 and N2O soil emissions in terrestrial ecosystems, with emphasis in Chilean and similar agro-ecosystems around the world. The influence of land use and crop management practices on CO2 and N2O emissions is analyzed; some mitigation measures to reduce such emissions are also discussed here. More knowledge on the biological processes that promote of GHG emissions from soil will allow creating opportunities for agricultural development under friendly-environmental conditions, where soil can act as a reservoir and/or emitter of GHG, depending on the balance of inputs and outputs.En actividades agrícolas los principales gases de efecto invernadero (GHG son los relacionados con los ciclos globales de C y N. El impacto de la agricultura sobre las emisiones GHG se ha convertido en una cuestión clave, especialmente si se considera que los ciclos naturales C y N se ven influidos por el desarrollo agrícola. Esta revisión se centra en emisiones de CO2 y N2O del suelo en los ecosistemas terrestres, con énfasis en agro-ecosistemas de Chile y similares alrededor del mundo. Se analiza la influencia del uso del suelo y las prácticas de manejo del cultivo sobre emisiones de CO2 y N2O, se discuten medidas de mitigación para reducir estas emisiones. Un mayor conocimiento sobre los procesos biológicos que promueven las emisiones GHG del suelo permitirá la creación de oportunidades para el desarrollo agrícola en condiciones ambientalmente amigables, donde el suelo puede actuar como un reservorio y/o emisor de GHG, dependiendo del balance de entradas y salidas.

Pathways to prepare perfect Co_4N thin films

International Nuclear Information System (INIS)

Gupta, Rachana; Pandey, Nidhi; Gupta, Mukul

2016-01-01

Magnetic nitrides of 3d transition metals (M = Fe,Co,Ni) are interesting materials for applications in magnetic devices. Controlled nitridation of magnetic metals for small N content (∼ 10-20 at.%) is sufficient to provide them high mechanical strength and superior chemical stability as compared to pure metals. At the same time tetra metal nitrides (M_4N) are known to posses a saturation magnetization (Ms) which is even higher than the pure metal. In M_4N enhanced magnetic moment is caused by a volume expansion (compared to a hypothetical fcc metal). All M_4N share a common fcc structure, in which metal atoms are arranged in the fcc positions and N atoms occupy the body centered positions. Such incorporation of N atoms results in an expansion of the fcc lattice. Theoretical studies suggest that such volume expansion enhances the itinerary of conduction band electrons and results in spreading of bandwidth of 3d electrons thereby suppression of exchange splitting leading to a larger (than pure metal) Ms. We did polarized neutron reflectivity (PNR) to measure Ms of Co_4N thin films. We found that as LP increases, Ms also increases. Our results clearly show that the Co_4N phase is formed at much lower Ts and when deposited at high Ts, N atoms diffuse out leaving behind pure fcc Co phase which seems to have been mistaken for Co_4N phase in earlier works

Evaluation of Cross-Section Data from Threshold to 40 MeV for some Neutron Reactions Important for Fusion Dosimetry Applications. Part 2 Evaluation of the Excitation Functions for the 59Co(n,3n)57Co, 89Y(n,2n)88Y, 93Nb(n,2n)92mNb, 169Tm(n,2n)168Tm and 209Bi(n,3n)207Bi Reactions

International Nuclear Information System (INIS)

Zolotarev, K.I.

2010-11-01

Evaluations of cross sections and their associated covariance matrices have been carried out for five dosimetry reactions: excitation functions were re-evaluated for the 89 Y(n,2n) 88 Y, 93 Nb(n,2n) 92 mNb and 169 Tm(n,2n) 168 Tm reactions over the neutron energy range from threshold up to 40 MeV; excitation functions were re-evaluated for the 59 Co(n,3n) 57 Co and 209 Bi(n,3n) 207 Bi reactions over the neutron energy range from threshold to 85 and 45 MeV, respectively. Uncertainties in the cross sections for all of those reactions were also derived in the form of relative covariance matrices. Benchmark calculations performed for 235 U thermal fission and 252 Cf spontaneous fission neutron spectra show that the integral cross sections calculated from the newly evaluated excitation functions exhibit improved agreement with related experimental data when compared with the equivalent data from the IRDF-2002 library. (author)

Interpretación en arqueología : piezas de collar de una necrópolis navarra

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Amparo Castiela Rodríguez

2005-01-01

Full Text Available Los restos de ajuar, recuperados en la necrópolis que han seguido el rito de la cremación, nos llegan muy alterados y requieren en ocasiones un esfuerzo especial para su comprensión. En el caso de varias piezas procedentes de La Atalaya, que formaban parte de collares, cuya interpretación ofrecemos

N-Acryloyl glycinamide

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Jan Seuring

2011-08-01

Full Text Available The molecule of the title compound [systematic name: N-(carbamoylmethylprop-2-enamide], C5H8N2O2, which can be radically polymerized to polymers with thermoresponsive behavior in aqueous solution, consists of linked essentially planar acrylamide and amide segments [maximum deviations = 0.054 (1 and 0.009 (1 Å] with an angle of 81.36 (7° between their mean planes. In the crystal, N—H...O hydrogen bonding leads to an infinite two-dimensional network along (100.

Clinical applications of brain spect with N-isopropyl-123I-p-iodoamphetamine

International Nuclear Information System (INIS)

Moretti, J.L.; Sergent, A.; Raynaud, C.; Baron, J.C.; Samson, Y.; Lassen, N.; Bourdoiseau, M.

1985-01-01

Single-photon emission computed tomography (SPECT) with N-isopropyl- 123 I-p-iodoamphetamine (IAMP-I-123) was used for 250 patients suffering from brain disorders, comprising brain tumours (36), normal-pressure hydrocephalus (NPH) (23), cerebrovascular pathologies (127) and partial epilepsy (64). Brain tumours were found to be hypoactive, whatever the grade and nature. Frontal hypoactivity was found in NPH patients, and IAMP-I-123 perfusion was improved after cerebral spinal fluid (CSF) lumbar drainage, giving a good predictive criterion of clinical outcome after CSF diversion. For cerebrovascular disorders, it was possible to obtain with IAMP-I-123 SPECT larger pictures of hypoactive areas than the pictures of hypodense lesions obtained with X-ray CT scans; other hypoactive areas that could not be observed with CT were also delineated by IAMP-I-123 SPECT. The hypoactive areas found in constituted infarctions can present two types of kinetics - those which are 'persistent' (still present on delayed scans performed 5 h after IAMP-I-123 injection) and those which disappear with time, thereby suggesting hypofunctional parenchyma without tissue impairment. IAMP-I-123 SPECT was proved to be useful in assessing ischaemia, especially in reversible ischaemia patients, by defining the affected arterial territory and guiding complementary arteriographic exploration in view of surgical procedures. IAMP-I-123 SPECT was able to accurately delineate the affected parenchymal areas. It could also be of help in the follow-up of the efficiency of drug therapy and surgery, and it can be regarded as a good predictive criterion for stroke rehabilitation. The results obtained with IAMP-I-123 indicate that the lesional and epileptogenic areas in epileptic patients are hypoactive. The localization of these territories by IAMP-I-123 SPECT correlates well with other, more accurate, neuroradiological and stereotactic techniques. (author)

Development and Validation of a Near-Infrared Spectroscopy Method for the Prediction of Acrylamide Content in French-Fried Potato.

Science.gov (United States)

Adedipe, Oluwatosin E; Johanningsmeier, Suzanne D; Truong, Van-Den; Yencho, G Craig

2016-03-02

This study investigated the ability of near-infrared spectroscopy (NIRS) to predict acrylamide content in French-fried potato. Potato flour spiked with acrylamide (50-8000 μg/kg) was used to determine if acrylamide could be accurately predicted in a potato matrix. French fries produced with various pretreatments and cook times (n = 84) and obtained from quick-service restaurants (n = 64) were used for model development and validation. Acrylamide was quantified using gas chromatography-mass spectrometry, and reflectance spectra (400-2500 nm) of each freeze-dried sample were captured on a Foss XDS Rapid Content Analyzer-NIR spectrometer. Partial least-squares (PLS) discriminant analysis and PLS regression modeling demonstrated that NIRS could accurately detect acrylamide content as low as 50 μg/kg in the model potato matrix. Prediction errors of 135 μg/kg (R(2) = 0.98) and 255 μg/kg (R(2) = 0.93) were achieved with the best PLS models for acrylamide prediction in Russet Norkotah French-fried potato and multiple samples of unknown varieties, respectively. The findings indicate that NIRS can be used as a screening tool in potato breeding and potato processing research to reduce acrylamide in the food supply.

Direct determination of acrylamide in food by gas chromatography-high-resolution time-of-flight mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Dunovska, Lenka [Institute of Chemical Technology, Department of Food Chemistry and Analysis, Technicka 3, 166 28 Prague 6 (Czech Republic); Cajka, Tomas [Institute of Chemical Technology, Department of Food Chemistry and Analysis, Technicka 3, 166 28 Prague 6 (Czech Republic); Hajslova, Jana [Institute of Chemical Technology, Department of Food Chemistry and Analysis, Technicka 3, 166 28 Prague 6 (Czech Republic)]. E-mail: jana.hajslova@vscht.cz; Holadova, Katerina [Institute of Chemical Technology, Department of Food Chemistry and Analysis, Technicka 3, 166 28 Prague 6 (Czech Republic)

2006-09-25

Simple and rapid gas chromatographic (GC) method employing a high-resolution time-of-flight mass analyzer that enables direct analysis (no derivatization) of acrylamide in various heat-processed foodstuffs has been developed and validated. Co-isolation of acrylamide precursors such as sugars and asparagine, constituting the risk of results overestimation due to additional formation of analyte in hot GC injector, is avoided by the extraction with n-propanol followed by solvent exchange to acetonitrile (MeCN). Introduction of a novel purification strategy, dispersive solid phase extraction, based on addition of primary-secondary amine (PSA) sorbent into deffated extract in MeCN, provides a significant reduction of some abundant matrix co-extracts (mainly free fatty acids). Isotope dilution technique (d{sub 3}-acrylamide as an internal standard) is employed for compensation of potential target analyte losses and/or matrix-inducted chromatographic response enhancement. Limits of quantifications (LOQs) ranged between 15 and 40 {mu}g kg{sup -1} and recoveries were between 97 and 108% depending on the examined food matrix. The repeatability of measurements (expressed as relative standard deviation, R.S.D.) was as low as 1.9% for potato crisps containing acrylamide at a level of 1 mg kg{sup -1}. Slightly higher values (R.S.D. < 4.0%) were achieved for breakfast cereals and crisp bread with approximately 10 times lower content of this processing contaminant. Trueness of results generated by this new method was demonstrated via FAPAS[reg] (Food Analysis Performance Assessment Scheme) interlaboratory proficiency tests.

Elevated CO2, not defoliation, enhances N cycling and increases short-term soil N immobilization regardless of N addition in a semiarid grassland

Science.gov (United States)

Elevated CO2 and defoliation effects on nitrogen (N) cycling in rangeland soils remain poorly understood. Here we tested whether effects of elevated CO2 and defoliation (clipping to 2.5 cm height) on N cycling depended on soil N availability (addition of 1 vs. 11 g N/m2) in intact mesocosms extracte...

Delayed lung scintigraphy with N-isopropyl-I-123-p-iodoamphetamine in lung cancer and inflammatory disease

Energy Technology Data Exchange (ETDEWEB)

Suematsu, Toru; Narabayashi, Isamu; Takada, Yoshiki and others

1989-01-01

Lung studies with N-Isopropyl-I-123-p-Iodoamphetamine (IMP) were performed on patients with lung cancer or inflammatory disease. In the present study, we evaluated the usefulness of the delayed scintigraphy. The subjects consisted of 27 patients with lung cancer (34 lesions), 3 with radiation pneumonitis, 2 with interstitial pneumonitis, 2 with old tuberculous lesion (tuberculomas), 1 with diffuse panbronchiolitis, 1 with pneumonia and 1 with lung abscess. The delayed scintigraphy was performed 24 hr after intravenous injection of 3 mCi IMP, in sitting position. In 10 patients, SPECT images were obtained following the delayed scintigraphy. Delayed scintigraphic appearances of lung cancer were classified into 5 types, high IMP uptake in the area congruent with the lesion of atelectasis and/or obstructive pneumonia (Type I), high IMP uptake in the area surrounded the tumor (Type II), a defect in the area consistent with the tumor and no high IMP uptake in the area surrounded the tumor (Type III), high IMP uptake in the area almost congruent with the tumor (Type IV) and no significant change (Type V). Excluding 10 lesions with Type IV or V, no IMP uptake was seen in the areas congruent with the tumors. Type II was the most frequently observed pattern. Normal scintigrams (Type V) were observed in 8 lesions, whose sizes were fairly small. There was no definite trend caused by difference in histological types of cancers. In 8 patients with viable inflammatory disease of the lung, the delayed scintigrams showed high IMP uptake in the areas congruent with the abnormalities on chest roentgenograms. On the other hand, no uptake was seen in the old tuberculous lesions. (J.P.N.).

Delayed lung scintigraphy with N-isopropyl-I-123-p-iodoamphetamine in lung cancer and inflammatory disease

International Nuclear Information System (INIS)

Suematsu, Toru; Narabayashi, Isamu; Takada, Yoshiki

1989-01-01

Lung studies with N-Isopropyl-I-123-p-Iodoamphetamine (IMP) were performed on patients with lung cancer or inflammatory disease. In the present study, we evaluated the usefulness of the delayed scintigraphy. The subjects consisted of 27 patients with lung cancer (34 lesions), 3 with radiation pneumonitis, 2 with interstitial pneumonitis, 2 with old tuberculous lesion (tuberculomas), 1 with diffuse panbronchiolitis, 1 with pneumonia and 1 with lung abscess. The delayed scintigraphy was performed 24 hr after intravenous injection of 3 mCi IMP, in sitting position. In 10 patients, SPECT images were obtained following the delayed scintigraphy. Delayed scintigraphic appearances of lung cancer were classified into 5 types, high IMP uptake in the area congruent with the lesion of atelectasis and/or obstructive pneumonia (Type I), high IMP uptake in the area surrounded the tumor (Type II), a defect in the area consistent with the tumor and no high IMP uptake in the area surrounded the tumor (Type III), high IMP uptake in the area almost congruent with the tumor (Type IV) and no significant change (Type V). Excluding 10 lesions with Type IV or V, no IMP uptake was seen in the areas congruent with the tumors. Type II was the most frequently observed pattern. Normal scintigrams (Type V) were observed in 8 lesions, whose sizes were fairly small. There was no definite trend caused by difference in histological types of cancers. In 8 patients with viable inflammatory disease of the lung, the delayed scintigrams showed high IMP uptake in the areas congruent with the abnormalities on chest roentgenograms. On the other hand, no uptake was seen in the old tuberculous lesions. (J.P.N.)

New Linear and Star-Shaped Thermogelling Poly([R]-3-hydroxybutyrate) Copolymers.

Science.gov (United States)

Barouti, Ghislaine; Liow, Sing Shy; Dou, Qingqing; Ye, Hongye; Orione, Clément; Guillaume, Sophie M; Loh, Xian Jun

2016-07-18

The synthesis of multi-arm poly([R]-3-hydroxybutyrate) (PHB)-based triblock copolymers (poly([R]-3-hydroxybutyrate)-b-poly(N-isopropylacrylamide)-b-[[poly(methyl ether methacrylate)-g-poly(ethylene glycol)]-co-[poly(methacrylate)-g-poly(propylene glycol)

Effect of different plasticizers on poly(N-vinyl-2-pyrrolidone) hydrogels cross-linked by radiation

International Nuclear Information System (INIS)

Alcantara, Mara Tania S.; Giannini, Danielle R.; Brant, Antonio J.C.; Riella, Humberto G.; Lugao, Ademar B.

2011-01-01

The use of hydrogel membranes usually demands polymers capable of forming films with high elastic and flexible properties besides having high water absorption. In terms of improvements of polymer plasticity, addition of special plasticizers to polymers can do it with promising results, although within limits of concentrations. The objective of this study was to evaluate the different effects of poly(enthylene glycol) (PEG) and glycerol as plasticizers on hydrogel membranes synthesized from poly(N-vinyl-2-pyrrolidone) (PVP) as the main polymer in aqueous polymeric solutions. For that, hydrogels of PVP/agar/PEG, PVP/agar/glycerol and without agar or plasticizer were simultaneously synthesized and sterilized by irradiation of mixtures of such products in aqueous solutions, using gamma-rays from 60 Co source at a dose of 25 kGy. The results based on gel fraction, swelling in water, and some mechanical tests suggest that the degree of PVP cross-linking prevailed over the greater hydrophilicity of glycerol compared to that of PEG with regard to the degree of swelling of the hydrogels. (author)

Effects of pore forming agents on chitosan-graft-poly(N-vinylpyrrolidone) hydrogel properties for use as a matrix for floating drug delivery

Science.gov (United States)

Budianto, E.; Al-Shidqi, M. F.; Cahyana, A. H.

2017-07-01

Eradicating H. pylori-based infection by using conventional oral dosage form of amoxicillin trihydrate finds difficulties to overcome rapid gastric retention time. Encapsulating amoxicillin trihydrate in floating drug delivery system may solve the problem. In this research, the floating drug delivery system of amoxicillin trihydrate encapsulated in floating chitosan-graft-poly(N-vinyl pyrrolidone) hydrogels containing CaCO3 and NaHCO3 as pore forming agents has been successfully prepared. Pore forming agents used was varied with the ratio of 10 to 25% pore forming agents to total mass of the used materials. The hydrogel were characterizedusing FTIR spectrophotometer and stereo microscope. As pore forming agents compositions increased, the porosity (%) and floating properties increased but followed by decrease in drug entrapment efficiency. Most of the floating hydrogels possessed floating ability longer than 180 min and the highest porosity was found in hydrogel containing 25% NaHCO3. Hydrogel containing CaCO3 showed sustained drug release profile than hydrogel containing NaHCO3. However, the optimum formulation was achieved at composition of 10% NaHCO3 with 57% of drug entrapped within the hydrogel and 43% drug released. The results of these studies show that NaHCO3 is an effective pore forming agents for chitosan-graft-poly(N-vinyl pyrrolidone) hydrogel preparation as compare to CaCO3.

Intelligent anticancer drug delivery performances of two poly(N-isopropylacrylamide)-based magnetite nanohydrogels.

Science.gov (United States)

Poorgholy, Nahid; Massoumi, Bakhshali; Ghorbani, Marjan; Jaymand, Mehdi; Hamishehkar, Hamed

2018-08-01

This article evaluates the anticancer drug delivery performances of two nanohydrogels composed of poly(N-isopropylacrylamide-co-itaconic anhydride) [P(NIPAAm-co-IA)], poly(ethylene glycol) (PEG), and Fe 3 O 4 nanoparticles. For this purpose, the magnetite nanohydrogels (MNHGs) were loaded with doxorubicin hydrochloride (DOX) as a universal anticancer drug. The morphologies and magnetic properties of the DOX-loaded MNHGs were investigated using transmission electron microscopy (TEM) and vibrating-sample magnetometer (VSM), respectively. The sizes and zeta potentials (ξ) of the MNHGs and their corresponding DOX-loaded nanosystems were also investigated. The DOX-loaded MNHGs showed the highest drug release values at condition of 41 °C and pH 5.3. The drug-loaded MNHGs at physiological condition (pH 7.4 and 37 °C) exhibited negligible drug release values. In vitro cytotoxic effects of the DOX-loaded MNHGs were extensively evaluated through the assessing survival rate of HeLa cells using the MTT assay, and there in vitro cellular uptake into the mentioned cell line were examined using fluorescent microscopy and fluorescence-activated cell sorting (FACS) flow cytometry analyses. As the results, the DOX-loaded MNHG1 exhibited higher anticancer drug delivery performance in the terms of cytotoxic effect and in vitro cellular uptake. Thus, the developed MNHG1 can be considered as a promising de novo drug delivery system, in part due to its pH and thermal responsive drug release behavior as well as proper magnetite character toward targeted drug delivery.

The topotactic dehydration of monoclinic {[Co(pht)(bpy)(H2O)2]·2H2O}n into orthorhombic [Co(pht)(bpy)(H2O)2]n (pht is phthalate and bpy is 4,4'-bipyridine).

Science.gov (United States)

Harvey, Miguel Angel; Suarez, Sebastián; Cukiernik, Fabio D; Baggio, Ricardo

2014-10-01

Controlled heating of single crystals of the previously reported [Köferstein & Robl (2007). Z. Anorg. Allg. Chem. 633, 1127-1130] dihydrate {[Co(pht)(bpy)(H2O)2]·2H2O}n, (II) [where pht is phthalate (C8H4O4) and bpy is 4,4'-bipyridine (C10H8N2)], produced a topotactic transformation into an unreported diaqua anhydrate, namely poly[diaqua(μ2-benzene-1,2-dicarboxylato-κ(2)O(1):O(2))(μ2-4,4'-bipyridine-κ(2)N:N')cobalt(II)], [Co(C8H4O4)(C10H8N2)(H2O)2]n, (IIa). The structural change consists of the loss of the two solvent water molecules linking the original two-dimensional covalent substructures which are the `main frame' of the monoclinic P2/n hydrate (strictly preserved during the transformation), with further reaccommodation of the latter. The anhydrate organizes itself in the orthorhombic system (space group Pmn2(1)) in a disordered fashion, where the space-group-symmetry restrictions are achieved only in a statistical sense, with mirror-related two-dimensional planar substructures, mirrored in a plane perpendicular to [100]. Thus, the asymmetric unit in the refined model is composed of two superimposed mirror-related `ghosts' of half-occupancy each. Similarities and differences with the parent dihydrate and some other related structures in the literature are discussed.

Structural, electronic, and mechanical properties of CoN and NiN. An ab initio study

Energy Technology Data Exchange (ETDEWEB)

Amudhavalli, A.; Manikandan, M.; Cinthia, A. Jemmy; Rajeswarapalanichamy, R. [NMSSVN College, Tamil Nadu (India). Dept. of Physics; Iyakutti, K. [SRM Univ., Tamil Nadu (India). Dept. of Physics and Nanotechnology

2017-07-01

The structural stabilities of cobalt mononitride (CoN) and nickel mono-nitride (NiN) were investigated among the crystal structures, namely, NaCl (B1), CsCl (B2), and zinc blende (B3). It was found that the zinc blende (B3) phase was the most stable phase for both nitrides. A pressure-induced structural phase transition from B3 to B1 phase was predicted in these nitrides. The computed lattice parameter values were in agreement with the experimental values and other theoretical values. The electronic structures reveal that these nitrides are metallic at zero pressure. The computed elastic constants indicate that CoN and NiN are mechanically stable in the B1 and B3 phases. The variations of the elastic constants, bulk modulus, shear modulus, Poisson's ratio, and elastic anisotropy factor with pressure were investigated. The Debye temperature θ{sub D} values are reported for both the nitrides in their B1 and B3 phases. The high-pressure NaCl phase of both CoN and NiN were found to be ferromagnetic.

Nanostructured poly(benzimidazole membranes by N-alkylation

Directory of Open Access Journals (Sweden)

J. Weber

2014-01-01

Full Text Available Modification of poly(benzimidazole (PBI by N-alkylation leads to polymers capable of undergoing microphase separation. Polymers with different amounts of C18 alkyl chains have been prepared. The polymers were analyzed by spectroscopy, thermal analysis, electron microscopy and X-ray scattering. The impact of the amount of alkyl chains on the observed microphase separation was analyzed. Membranes prepared from the polymers do show microphase separation, as evidenced by scattering experiments. While no clear morphology could be derived for the domains in the native state, evidence for the formation of lamellar morphologies upon doping with phosphoric acid is provided. Finally, the proton conductivity of alkyl-modified PBI is compared with that of pure PBI, showing that the introduction of alkyl side chains does not result in significant conductivity changes.

Evaluation of cerebral perfusion imaging with N-isopropyl-p-[123I]iodoamphetamine (IMP) in the cases of antiphospholipid syndrome

International Nuclear Information System (INIS)

Kato, Toru; Nanbu, Ichiro; Tohyama, Junko; Ohba, Satoru

1995-01-01

Five cases of antiphospholipid syndrome with mild headache, but without any neurological deficits and abnormal findings by CT and MRI, were examined by cerebral blood perfusion SPECT using N-isopropyl-p-[ 123 I] iodoamphetamine (IMP). Although three cases were performed quantification of cerebral blood flow with a microsphere method simultaneously, their values were within normal limits. Two of them showed focal low perfusion areas. One case had relatively low perfusion areas in the bilateral occipital lobes and the right temporal lobe, which improved after treatment. One of two had low perfusion in the bilateral occipital lobes. Other three cases only showed ununiformity of radioisotope uptake on the cerebral blood perfusion SPECT. Low perfusion areas in antiphospholipid syndrome might be caused by microarterial thrombosis, microvenous thrombosis or spasms, although they could be reversible. As early irreversible progress of cerebral blood flow, cerebral blood flow SPECT should be performed in cases of antiphospholipid syndrome with neurological complainments. (author)

Comparative study of nuclear magnetic resonance and UV-visible spectroscopy dose-response of polymer gel based on N-(Isobutoxymethyl) acrylamide

Science.gov (United States)

Lotfy, S.; Basfar, A. A.; Moftah, B.; Al-Moussa, A. A.

2017-12-01

A comparative study of nuclear magnetic resonance and UV-visible spectroscopy of dose-response for polymer gel dosimeters was performed. Dosimeters were prepared using N-(Isobutoxymethyl) acrylamide (NIBMA) as a new monomer via radiation induced polymerization for use in radiotherapy planning. The prepared dosimeters were irradiated with doses up to 30 Gy at a constant dose rate of 600 MU/min. Using a medical linear accelerator at irradiation energies of 6, 10 and 18 MV photon beam. The nuclear magnetic resonance (NMR), via spin-spin relaxation rate (R2) for water proton surrounding the polymer formulation and UV-Visible spectroscopy, via the optical absorbance measurements of irradiated dosimeters at selected wavelengths of 500 nm, was used to investigate the dose response of NIBMAGAT gel dosimeters. Scavenge of oxygen was done using tetrakis (hydroxymethyl) phosphonium chloride (THPC). The THPC optimum concentration in the dosimeters formulations were 5 and 10 mM for the NMR and optical absorbance measurements respectively. The quantitative investigation of the dosimeters components reveals the selective formulations based on 4% w/w gelatin, 1% w/w NIBMA, 3% w/w BisAAm, 5 or 10 mM THPC and 17% w/w glycerol which significantly increase the dosimeters dose response. The prepared dosimeters were found to be dose rate and photon beam irradiation energy independent. The stability study shows no change in the relaxation rate or in the optical absorbance of the gel dosimeters up to 8 days post-irradiation. The prepared polymer gel dosimeters at the energies of 6, 10 and 18 MV photon beam irradiation in the range of 1-30 Gy have the linearity of the dose response function in the case of R2 is better than in the case of absorbance measurements; correlation coefficient (r2) equals 0.995 and 0.991, respectively. Dose sensitivity, R2 of NIBMAGAT dosimeters (0.0775 s-1 Gy-1). The absorption band intensity increases linearly with a dose sensitivity of 0.016 cm-1 Gy-1. The

Modificación estructural de Poli(Acido Láctico) (PLA) mediante extrusión reactiva: estudio preliminar en mezclador interno escala laboratorio

OpenAIRE

Espejo, Lucas

2011-01-01

Doble titulació Este proyecto, realizado en Centro Catalá del Plástico y por lo tanto implicado en el dominio de los polímeros, pretende preparar y caracterizar sistemas de Acido Poli(Láctico) (PLA) con extensores de cadena (CE) que serían adecuados y eficientes para el sector de los envases. Los procesos tal la Inyección y/o Extrusión empleando el PLA en este campo se enfrentan a la pérdida de las propiedades termo-mecánicas. Es el resultado de la degradación térmica y h...

Evaluación higiénica previa de acrilamida en aire durante la preparación de gel de poliacrilamida (PAA en un laboratorio de genética

Directory of Open Access Journals (Sweden)

Antonio Blein Sánchez de León

2007-06-01

Full Text Available Objetivos: Conocer el nivel aproximado de concentración en aire de Acrilamida, cancerígeno y mutagénico tipo 2, durante la preparación del gel de Poliacrilamida en el Laboratorio, para verificar si la situación higiénica es tolerable, o si no lo es, para tomar medidas preventivas inmediatamente, antes de llevar a cabo una evaluación detallada con arreglo a UNE-EN 689, con un coste notablemente mayor. Metodología: Una vez seleccionadas las etapas de preparación del gel donde hay emisión de Acrilamida, el método higiénico seguido ha sido el PV2004, de NIOSH, para la toma de muestra y el análisis. Resultados: La concentración de Acrilamida detectada en la fase de pesada es de 723% del Valor Limite de Exposición Profesional para exposición diaria y del 145% del Valor Limite de Exposición Profesional para Corta Exposición. En la fase de agitación no se detecto Acrilamida en la muestra. Conclusiones: Es necesario tomar medidas preventivas inmediatamente. Se proponen varias medidas. Una vez aplicadas, se recomienda realizar la evaluación higiénica según UNE-EN 689.Aims: To know the approximate level of Acrylamide, carcinogenic type 2, in air, during the preparation of Polyacrylamide-Gel in the laboratory, in order to determine if the occupational hygiene situation is acceptable or not, in order to, if not, to implement immediately preventive measurements, before carring out an hygienical assessment following the UNE-EN 689 standard, with much higher costs. Methods: After the selection of the gel-preparation stages, where evaporation of Acrylamide takes place, the followed method was PV2004, from NIOSH, for the sample collection and for the analyse. Results: The detected level of Acrylamide in the weighting stage is 723 % of the TLV-TWAand 145% of the TLV-C. In the stirring stage there was found no Acrylamide. Conclusions: It is necessary to implement immediately preventive measurements. Some of them are proposed. Once implemented

Obtención por atomización y evaluación de agregados esféricos. Un nuevo excipiente co-procesado para compresión directa

OpenAIRE

Sarrate Arjona, Rocío

2017-01-01

[spa] La aparición de los excipientes co-procesados se debe principalmente a la creciente apreciación del rol que desempeñan los excipientes en los comprimidos y a la mayor tendencia a su fabricación, especialmente por compresión directa, por las ventajas que aporta, tanto económicas como de proceso. Los excipientes co-procesados son combinaciones de dos o más excipientes establecidos que, a nivel particular son diseñados para modificar físicamente alguna de sus propiedades de una forma inal...

Experimental Investigation of Mechanical and Thermal Properties of Silica Nanoparticle-Reinforced Poly(acrylamide) Nanocomposite Hydrogels.

Science.gov (United States)

Zaragoza, Josergio; Babhadiashar, Nasim; O'Brien, Victor; Chang, Andrew; Blanco, Matthew; Zabalegui, Aitor; Lee, Hohyun; Asuri, Prashanth

2015-01-01

Current studies investigating properties of nanoparticle-reinforced polymers have shown that nanocomposites often exhibit improved properties compared to neat polymers. However, over two decades of research, using both experimental studies and modeling analyses, has not fully elucidated the mechanistic underpinnings behind these enhancements. Moreover, few studies have focused on developing an understanding among two or more polymer properties affected by incorporation of nanomaterials. In our study, we investigated the elastic and thermal properties of poly(acrylamide) hydrogels containing silica nanoparticles. Both nanoparticle concentration and size affected hydrogel properties, with similar trends in enhancements observed for elastic modulus and thermal diffusivity. We also observed significantly lower swellability for hydrogel nanocomposites relative to neat hydrogels, consistent with previous work suggesting that nanoparticles can mediate pseudo crosslinking within polymer networks. Collectively, these results indicate the ability to develop next-generation composite materials with enhanced mechanical and thermal properties by increasing the average crosslinking density using nanoparticles.

DNA-Directed alkylating agents. 7. Synthesis, DNA interaction, and antitumor activity of bis(hydroxymethyl)- and bis(carbamate)-substituted pyrrolizines and imidazoles.

Science.gov (United States)

Atwell, G J; Fan, J Y; Tan, K; Denny, W A

1998-11-19

A series of bis(hydroxymethyl)-substituted imidazoles, thioimidazoles, and pyrrolizines and related bis(carbamates), linked to either 9-anilinoacridine (intercalating) or 4-(4-quinolinylamino)benzamide (minor groove binding) carriers, were synthesized and evaluated for sequence-specific DNA alkylation and cytotoxicity. The imidazole and thioimidazole analogues were prepared by initial synthesis of [(4-aminophenyl)alkyl]imidazole-, thioimidazole-, or pyrrolizine dicarboxylates, coupling of these with the desired carrier, and reduction to give the required bis(hydroxymethyl) alkylating moiety. The pyrrolizines were the most reactive alkylators, followed by the thioimidazoles, while the imidazoles were unreactive. The pyrrolizines and some of the thioimidazoles cross-linked DNA, as measured by agarose gel electrophoresis. Strand cleavage assays showed that none of the compounds reacted at purine N7 or N3 sites in the gpt region of the plasmid gpt2Eco, but the polymerase stop assay showed patterns of G-alkylation in C-rich regions. The corresponding thioimidazole bis(carbamates) were more selective than the bis(hydroxymethyl) pyrrolizines, with high-intensity bands at 5'-NCCN, 5'-NGCN and 5'-NCGN sequences in the PCR stopping assay ( indicates block sites). The data suggest that these targeted compounds, like the known thioimidazole bis(carbamate) carmethizole, alkylate exclusively at guanine residues via the 2-amino group, with little or no alkylation at N3 and N7 guanine or adenine sites. The cytotoxicities of the compounds correlated broadly with their reactivities, with the bis(hydroxymethyl)imidazoles being the least cytotoxic (IC50s >1 microM; P388 leukemia) and with the intercalator-linked analogues being more cytotoxic than the corresponding minor-groove-targeted ones. This was true also for the more reactive thioimidazole bis(carbamates) (IC50s 0.8 and 11 microM, respectively), but both were more active than the analogous "untargeted" carmethizole (IC50 20

Simultaneous determination of mercapturic acids derived from ethylene oxide (HEMA), propylene oxide (2-HPMA), acrolein (3-HPMA), acrylamide (AAMA) and N,N-dimethylformamide (AMCC) in human urine using liquid chromatography/tandem mass spectrometry.

Science.gov (United States)

Schettgen, Thomas; Musiol, Anita; Kraus, Thomas

2008-09-01

Mercapturic acids are highly important and specific biomarkers of exposure to carcinogenic substances in occupational and environmental medicine. We have developed and validated a reliable, specific and very sensitive method for the simultaneous determination of five mercapturic acids derived from several high-production chemicals used in industry, namely ethylene oxide, propylene oxide, acrylamide, acrolein and N,N-dimethylformamide. Analytes are enriched and cleaned up from urinary matrix by offline solid-phase extraction. The mercapturic acids are subsequently separated by means of high-performance liquid chromatography on a Luna C8 (2) column and specifically quantified by tandem mass spectrometric detection using isotopically labelled analytes as internal standards. The limits of detection (LODs) for N-acetyl-S-2-carbamoylethylcysteine (AAMA) and N-acetyl-S-2-hydroxyethylcysteine (HEMA) were 2.5 microg/L and 0.5 microg/L urine, while for N-acetyl-S-3-hydroxypropylcysteine (3-HPMA), N-acetyl-S-2-hydroxypropylcysteine (2-HPMA) and N-acetyl-S-(N-methylcarbamoyl)cysteine (AMCC) it was 5 microg/L. These LODs were sufficient to detect the background exposure of the general population. We applied the method on spot urine samples of 28 subjects of the general population with no known occupational exposure to these substances. Median levels for AAMA, HEMA, 3-HPMA, 2-HPMA and AMCC in non-smokers (n = 14) were 52.6, 2.0, 155, 7.1 and 113.6 microg/L, respectively. In smokers (n = 14), median levels for AAMA, HEMA, 3-HPMA, 2-HPMA and AMCC were 243, 5.3, 1681, 41.7 and 822 microg/L, respectively. Due to the simultaneous quantification of these mercapturic acids, our method is well suited for the screening of workers with multiple chemical exposures as well as the determination of the background excretion of the general population.

A new graphic method for evaluation of distribution volume on N-isopropyl-p-[123I]iodoamphetamine (IMP) SPECT

International Nuclear Information System (INIS)

Odano, Ikuo; Takahashi, Naoya; Ohtaki, Hiroh; Noguchi, Eikichi; Hatano, Masayoshi; Yamasaki, Yoshihiro; Nishihara, Mamiko; Ohkubo, Masaki; Yokoi, Takashi.

1993-01-01

We developed a new graphic method using N-isopropyl-p-[ 123 I]iodoamphetamine (IMP) and SPECT of the brain, the graph on which all three parameters, cerebral blood flow, distribution volume (V d ) and delayed count to early count ratio (Delayed/Early ratio), were able to be evaluated simultaneously. The kinetics of 123 I-IMP in the brain was analyzed by a 2-compartment model, and a standard input function was prepared by averaging the time activity curves of 123 I-IMP in arterial blood on 6 patients with small cerebral infarction etc. including 2 normal controls. Being applied this method to the differential diagnosis between Parkinson's disease and progressive supranuclear palsy, we were able to differentiate both with a glance, because the distribution volume of the frontal lobe significantly decreased in Parkinson's disease (Mean±SD; 26±6 ml/g). This method was clinically useful. We think that the distribution volume of 123 I-IMP may reflect its retention mechanism in the brain, and the values are related to amine, especially to dopamine receptors and its metabolism. (author)

Single photon emission computed tomography with N-isopropyl-p-[123I] iodoamphetamine in dementia of the Alzheimer type

International Nuclear Information System (INIS)

Tsunoda, Masahiko; Fujii, Tsutomu; Tanii, Yasuyuki; Yasui, Shinichi; Yuasa, Satoru; Shimizu, Akinori; Kurachi, Masayoshi; Seki, Hiroyasu; Fukuta, Tsutomu.

1989-01-01

Correlation between brain uptake of N-isopropyl-p-[I-123]iodoamphetamine (I-123 IMP), as shown on single photon emission computed tomography (SPECT) scans, and clinical stages was examined in 8 patients with Alzheimer type dementia. The patients were clinically staged as Stage I (3), Stage II (3), or Stage III (2). The count ratio of each cerebral lobe to the cerebellum was calculated on horizontal SPECT scans. Stage I patients had a decreased I-123 IMP uptake in the temporal and parietal lobes. The decreased uptake in these areas became marked in Stage II patients, with diffusely slight uptake of I-123 IMP in the brain. In Stage III patients, the uptake of I-123 IMP was markedly decreased in the whole brain, including temporal, parietal, and frontal lobes. For five patients of Stage II and III, bilateral differences in the cerebral hemispheres were observed, corresponding to neurologic symptoms. Iodine-123 IMP SPECT was thus considered useful in clinically evaluating Alzheimer type dementia and in determining degenerative process of this disease. (Namekawa, K)

Regional cerebral blood flow in Parkinson's disease measured with N-isopropyl-p-[[sup 123]I]iodoamphetamine (IMP) SPECT

Energy Technology Data Exchange (ETDEWEB)

Odano, Ikuo; Nishihara, Mamiko; Hayashi, Hiroko; Higuchi, Shoichi; Sakai, Kunio [Niigata Univ. (Japan). School of Medicine; Ishikawa, Atsushi; Ibayashi, Katsuhiko

1992-09-01

N-isopropyl-p-[[sup 123]I]iodoamphetamine (IMP) SPECT studies were performed on 21 patients (13 females; 45-73 yrs) with idiopathic Parkinson's disease (PD) and 10 age-matched normal controls (39-69 yrs). Regional cerebral blood flow (rCBF) was quantitatively measured by the arterial blood sampling method. When compared with normal controls, global CBF, and rCBF in the frontal cortex and in the basal ganglia were reduced 22.1% (p<0.01), 25.0% (p<0.05) and 25.6% (p<0.01), respectively. The reduction of rCBF in the basal ganglia was significantly correlated (p<0.05) with symptoms such as gait disturbance, frozen gait and motor disability score. However, no significant correlation was observed between the severity of dementia and any regional reduction of CBF, including the frontal or parietal cortices. These data show that the severity of dementia in PD may be related to other factors but not with CBF. Quantification of rCBF with [sup 123]I-IMP SPECT imaging is useful for evaluation and follow-up of patients with PD. (author).

Regional quantitative noninvasive assessment of cerebral perfusion and function with N-Isopropyl-[123I]p-iodoamphetamine

International Nuclear Information System (INIS)

von Schulthess, G.K.; Ketz, E.; Schubiger, P.A.; Bekier, A.

1985-01-01

Although several reports on the clinical usefulness of N-isopropyl-[ 123 I]p-iodoamphetamine (IMP) in the diagnosis of cerebral disease have appeared in the literature, quantitative, noninvasive measurements of regional cerebral blood flow with this method pose difficulties because cerebral IMP uptake not only depends on cerebral perfusion but also on cerebral function. Rather than trying to develop a method to measure cerebral perfusion with IMP, the authors have chosen to test a method to quantitatively evaluate planar and emission computed tomographic (ECT) studies by comparing the data obtained in patients with established pathology with the data obtained in a group of normal individuals. Using this method, absolute cerebral IMP uptake (counts/pixel/mCi/min) and planar anterior right-left ratios were obtained. Also measured were right-left ratios obtained from 12 paired regions in three ECT slices. The evaluation of the patients cerebral IMP uptake asymmetries relative to the normal standard values is a useful adjunct to qualitative image analysis in assessing the presence ans severity of disease, as qualitative analysis is prone to false-positive and negative results. Cerebral IMP uptake as measured in cts/pixel/mCi/min is abnormal only in severe cerebral disease and therefore generally a less helpful parameter

Properties of Fe{sub 8−N}Co{sub N} nanoribbons and nanowires: A DFT approach

Energy Technology Data Exchange (ETDEWEB)

Muñoz, Francisco [Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Germany); Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 7800024 (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnología, CEDENNA, Avda. Ecuador 3493, Santiago 9170124 (Chile); Altbir, D. [Centro para el Desarrollo de la Nanociencia y la Nanotecnología, CEDENNA, Avda. Ecuador 3493, Santiago 9170124 (Chile); Departamento de Física, Universidad de Santiago (Chile); Kiwi, Miguel, E-mail: m.kiwi.t@gmail.com [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 7800024 (Chile); Centro para el Desarrollo de la Nanociencia y la Nanotecnología, CEDENNA, Avda. Ecuador 3493, Santiago 9170124 (Chile); Morán-López, J.L. [Departamento de Física, Laboratorio Interdisciplinario, Facultad de Ciencias, Universidad Nacional Autónoma de México, México, D.F. (Mexico)

2013-08-15

The structural configurations and magnetic properties of zig-zag nanoribbons and nanowires of Fe{sub 8−N}Co{sub N}, for 0≤N≤8, are calculated within the density functional theory. Both, for the zig-zag nanoribbons and the nanowires, there is a tendency towards forming Fe–Co bonds, while segregation of the Fe and Co is energetically unfavorable. For the nanowire structures a transition from bcc Fe to hcp Co spatial arrangements is observed when N is increased from 4 to 6, in spite of the small size of the systems under investigation. The energy minimization was performed taking into consideration the electronic and magnetic structures, since for each crystalline structure, chemical composition, and short range order, particular magnetic properties of these systems do correspond. The magnetocrystalline anisotropy energy is calculated, and it is found that the easy axis changes from a transverse direction in Fe-rich systems, to the axial direction as the Co concentration increases. It is also found that although there are important variations of the local magnetic moment of the components, and their particular location in the system, the average magnetic moment is an almost linear function of N. - Highlights: ► Properties of Fe{sub 8−N}Co{sub N} nanoribbons and nanowires are calculated ab initio. ► Structural and magnetic properties of nanoribbons and nanowires are calculated. ► Shape and crystalline anisotropies of nanoribbons and nanowires are contrasted.

Analysis of hemoglobin adducts from acrylamide, glycidamide, and ethylene oxide in paired mother/cord blood samples from Denmark

DEFF Research Database (Denmark)

von Stedingk, Hans; Vikström, Anna C; Rydberg, Per

2011-01-01

The knowledge about fetal exposure to acrylamide/glycidamide from the maternal exposure through food is limited. Acrylamide, glycidamide, and ethylene oxide are electrophiles and form adducts with hemoglobin (Hb), which could be used for in vivo dose measurement. In this study, a method.......20-0.73) for glycidamide, and 0.43 (range 0.17-1.34) for ethylene oxide. In vitro studies with acrylamide and glycidamide showed a lower (0.38-0.48) rate of adduct formation with Hb in cord blood than with Hb in maternal blood, which is compatible with the structural differences in fetal and adult Hb. Together...... for analysis of Hb adducts by liquid chromatography-mass spectrometry, the adduct FIRE procedure, was applied to measurements of adducts from these compounds in maternal blood samples (n = 87) and umbilical cord blood samples (n = 219). The adduct levels from the three compounds, acrylamide, glycidamide...

Studies on the Use of Gamma Radiation-Induced for Preparation of Some Modified Resins for the Separation of Some Metal Ions

International Nuclear Information System (INIS)

Abo-Zahra, S.F.

2012-01-01

The work carried out in the present thesis is based on preparation, characterization and applications of some modified resins such as: poly(acrylamide)/poly(maleic acid) P(AAm)/P(MA) interpolymer complex (resin), poly(acrylamide-acrylic acid-amidoxime) P(AAm-AA-AO) resin and poly(hydroxamic acid) P(HA) resin. Poly(acrylamide)/poly(maleic acid) P(AAm)/P(MA) interpolymer complex (resin) was prepared by template polymerization of maleic acid (MA) monomer on poly(acrylamide) P(AAm) hydrogel as a template polymer in the presence of N,N'-methylenebisacrylamide (NMBA) as a crosslinker using gamma radiation-induced technique. Poly(acrylamide-acrylic acid-amidoxime) P(AAm-AA-AO) resin was prepared by template polymerization of acrylic acid (AA) and acrylonitrile (AN) monomers on P(AAm) hydrogel as a template polymer in the presence of NMBA as a crosslinker using gamma radiation-induced technique. The conversion of nitrile group to amidoxime one was carried out by the treatment of the prepared resin with an alkaline solution of hydroxylamine. Poly(hydroxamic acid) P(HA) resin was prepared from the reaction of the corresponding water-soluble P(AAm) previously prepared by gamma radiation-induced with hydroxylamine hydrochloride in an alkaline medium. The functional groups on the prepared polymeric resins were confirmed by using Fourier transform infrared (FTIR) spectra. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) measurements, scanning electron microscopy (SEM) and electron spin resonance (ESR) measurements were performed to evaluate the properties of the prepared polymeric resins, free or complexed with metal ions such as Cu 2+ metal ions.

Poly[[[diaquacobalt(II]-bis[μ2-1,1′-(butane-1,4-diyldiimidazole-κ2N3:N3′

Directory of Open Access Journals (Sweden)

2009-03-01

Full Text Available In the title compound, {[Co(C10H14N42(H2O2](NO32}n, the CoII ion lies on an inversion center and is six-coordinated in an octahedral environment by four N atoms from four different 1,1′-butane-1,4-diyldiimidazole ligands and two O atoms from the two water molecules. The CoII atoms are bridged by ligands, generating a two-dimensional (4,4-network. Adjacent fishnet planes are linked to the nitrate anions via O—H...O hydrogen bonds, forming a three-dimensional supramolecular structure.

Synthesis and cathodoluminescence of Sb/P co-doped GaN nanowires

International Nuclear Information System (INIS)

Wang, Zaien; Liu, Baodan; Yuan, Fang; Hu, Tao; Zhang, Guifeng; Dierre, Benjamin; Hirosaki, Naoto; Sekiguchi, Takashi; Jiang, Xin

2014-01-01

Sb/P co-doped Gallium Nitride (GaN) nanowires were synthesized via a simple chemical vapor deposition (CVD) process by heating Ga 2 O 3 and Sb powders in NH 3 atmosphere. Scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy (EDS) measurements confirmed the as-synthesized products were Sb/P co-doped GaN nanowires with rough morphology and hexagonal wurtzite structure. Room temperature cathodoluminescence (CL) demonstrated that an obvious band shift of GaN nanowires can be observed due to Sb/P co-doping. Possible explanation for the growth and luminescence mechanism of Sb/P co-doped GaN nanowires was discussed. Highlight: • Sb/P co-doped GaN nanowires were synthesized through a well-designed multi-channel chemical vapor deposition (CVD) process. • Sb/P co-doping leads to the crystallinity deterioration of GaN nanowires. • Sb/P co-doping caused the red-shift of GaN nanowires band-gap in UV range. • Compared with Sb doping, P atoms are more easy to incorporate into the GaN lattice

Study of chemical interaction induced by ionizing radiation poly(dimethylsiloxane-g-ethylene oxide) in the poly(n-vinyl-2-pyrrolidone) and agar membrane; Estudo da interacao quimica do poli(dimetilsiloxano-g-oxido de etileno) na membrana de poli(n-vinil-2-pirrolidona) e agar induzida com radiacao ionizante

Energy Technology Data Exchange (ETDEWEB)

Bazzi, Aurea de Souza

1999-07-01

Membrane composed by poly(N-vinyl-2-pyrrolidone) (PVP) and agar was formulated with and without poly(dimethylsiloxane-g-ethylene oxide) (SEO) irradiated with electron beam with doses between 10-50 kGy. The radiolytic behaviour of each component, PVP, agar and SEO, was studied when irradiated by gamma ray, in the absence and presence of air and water, by electron paramagnetic resonance (EPR) at 77 K. The chemical interaction of SEO with PVP/agar membrane was investigated by: infrared spectroscopy, energy dispersive X-ray fluorescence, dynamic-mechanical analysis, scanning electron microscopy, gel and swelling analysis. The cytotoxicity of the PVP/agar/SEO membrane was evaluated by cellular suppression. The membrane radicals from PVP ({phi}NC.) and from water (H., OH. and H{sub 2}O) was observed by EPR at 77K. The agar radicals formed by hydrogen abstraction of C{sub 1} and C{sub 3} of {beta}-D-galactose and/or C{sub 1} and C{sub 4} of {alpha}-L-galactose, reacted primarily with water radicals in despite of they also took part in the membrane by chemical bond. The radicals from SEO (.CH{sub 2}{approx}, .Si{approx}, .O{approx}) participated in the inter and intramolecular crosslinking as co-crosslinker by polymeric bridge. The co-crosslinked action depended on its concentration associated to PVP concentration. The presence op acrylates increases the tensile break of the PVP/agar/SEO membrane significantly. (author)

Application of polyacrylic acid-poly-N,N-dimethyldiallylammonium chloride polyelectrolyte complexes for structuring of polluted soil of Semipalatinsk nuclear test site

International Nuclear Information System (INIS)

Sabantseva, T.; Bashenova, A.; Orazzhanova, L.K.; Yashkarova, M.G.; Bimendina, L.A.

2002-01-01

The present communication is devoted to investigation of structuring efficiency of polyacrylic acid-poly-N,N-dimethyldiallylammonium chloride (PAA-PDMDAACI) polyelectrolyte complexes. The granulometric analysis of selected soil samples before and after the treatment of aqueous solution of PAA, PDMDAACI and PAA-PDMDAACI complexes at different molar ratio of polymer components and polymer concentrations was carried out. Analysis shows that nonstoichiometric polyelectrolyte complex [PAA]:[PDMDAACI]=3:1 possesses the best structuring effect. But this result is worse than in the case using of [PAA]:[polyethylene glycol]=1:1 inter-polymer complex

Preparation and characterization of thermal-responsive non-woven poly (propylene) materials grafted with N-isopropylacrylamide/β-cyclodextrin

DEFF Research Database (Denmark)

Amiri, Setareh; Zadhoush, Ali; Mallakpour, Shadpour

2013-01-01

A temperature-sensitive hydrogel was successfully grafted on the surface of non-woven poly(propylene) materials. This was carried out by the application of unmodified β-cyclodextrin and N-isopropylacrylamide monomer in order to develop new functional hydrogels for textile science and technology......(N-isopropylacrylamide) and β-cyclodextrin components on the surface of the textile. Unmodified β-cyclodextrin content was estimated by the use of elemental analysis to be 97 µg/cm2. The water uptake measurements and differential scanning calorimetry analyses showed that the hydrogel maintained its temperature...... of smart textiles which possess the temperature-sensitive property of poly(N-isopropylacrylamide) and the ability of inclusion complex formation with guest molecules due to the presence of unmodified β-cyclodextrin in the hydrogel network....

Enhanced CO_2 capture on graphene via N, S dual-doping

International Nuclear Information System (INIS)

Li, Jieyuan; Hou, Meiling; Chen, Yanqiu; Cen, Wanglai; Chu, Yinghao; Yin, Shi

2017-01-01

Highlights: • Sluggish conjugated π bonds of graphene should be weakened to promote adsorption activity. • A charge delivery channel along S → N → CO_2 path should be prior responsible for the enhancement of CO_2 capture on graphene. • Applicative temperature range of graphene-based adsorbents for CO_2 capture is extend to about 100 °C via N, S dual-doping. - Abstract: N, S doped graphene-based materials have been recently recognized as promising adsorbents for CO_2 capture, but understanding of the adsorption mechanism at the atomic level is still limited. Herein, the local structures and promotion mechanism of CO_2 capture by N, S doped graphene were investigated by combining density functional theory and ab initio thermodynamics. A single vacancy defected graphene involving N, S dual-doping was found to be a superior adsorbent for CO_2 capture under mild conditions (<100 °C, 1 atm). The enhanced CO_2 adsorption performance should be ascribed to a charge delivery channel along the S → N → CO_2 path, leading to extra charge transfer from graphene to CO_2. It is worth mentioning that the extra charge transfer was stimulated by the unique sp"2 hybridization of pyridine N and further enhanced by S in N, S dual-doped graphene. A possible mechanism has been proposed to explain the high adsorption performance of CO_2 by N, S dual-doped graphene, which offers insights for the design of new graphene-based adsorbents.

PRODUCCIÓN DE POLI-β -HIDROXIBUTIRATO (PHB β POR Ralstonia eutropha ATCC 17697

Directory of Open Access Journals (Sweden)

Barbosa Marcela

2005-06-01

Full Text Available Ralstonia eutropha es la bacteria más utilizada en la producción de poli-β-hidroxibutirato (PHB por su capacidad de acumular polímero hasta en un 80% de su peso seco. En el presente trabajo se realizaron fermentaciones por lote alimentado en dos etapas a escala 3 litros usando tres concentraciones de fructosa (5, 10 y 15 g/l. En la primera etapa, manteniendo constante la relación carbono-nitrógeno en 6.85 g C/g N, se buscó obtener una alta concentración celular; en la segunda etapa las células obtenidas se limitaron en la fuente de nitrógeno para permitir la acumulación del biopolímero. La mejor concentración para producir el material es 5 g/l en la cual se obtuvo un porcentaje de acumulación del 66.2%, una velocidad de crecimiento específico inicial de 0.5171 h-1 y una productividad de 0.1245 g PHB/ l h.

Single photon emission computed tomography (SPECT) findings using N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) in schizophrenia and atypical psychosis

International Nuclear Information System (INIS)

Suga, Hidemichi; Hayashi, Takuji; Mitsugi, Ohara

1994-01-01

As a basis for possible classification of schinzophrenic psychoses into schizophrenia and atypical psychosis, we studied the brain functional differences among 16 schizophrenic patients, 16 atypical psychosis patients and 16 healthy volunteers by single photon emission computed tomography (SPECT) using N-isopropyl-p-[ 123 I] iodoamphetamine. As a result, schizophrenics showed hypofrontality. On the other hand, atypical psychotics had no such hypofrontality but showed a reduced uptake rate in the right thalamic region. No influence of sex, duration of illness and medication was confirmed by the findings. The results suggest that schizophrenics might have some lesions in the frontal regions, whereas atypical psychotics might have no such lesions, but dysfunction in the right thalamic region. Consequently, the SPECT findings as least indicate possibly different etiologies for schizophrenia and atypical psychosis. (author)

The Co-III-C bond in (1-thia-4,7-diazacyclodecyl-kappa N-3(4),N-7,C-10)(1,4,7-triazacyclononane-kappa N-3(1),N-4,N-7)-cobalt(III) dithionate hydrate

DEFF Research Database (Denmark)

Harris, Pernille; Kofod, P.; Song, Y.S.

2003-01-01

In the title compound, [Co(C6H15N3)(C7H15N2S)]S2O6.H2O, the Co-C bond distance is 1.9930 (13) Angstrom, which is shorter than for related compounds with the linear 1,6-diamino-3-thiahexan-4-ide anion in place of the macrocyclic 1-thia-4,7-diazacyclodecan-8-ide anion. The coordinated carbanion pro...... produces an elongation of 0.102 (7) Angstrom of the Co-N bond to the 1,4,7-triazacyclononane N atom in the trans position. This relatively small trans influence is presumably a result of the triamine ligand forming strong bonds to the Co-III atom....

COMPORTAMIENTO DEL CONSUMIDOR EN LA CO-CREACIÓN DE VALOR Y SU RELACIÓN CON LA SATISFACCIÓN EN EL ENTORNO UNIVERSITARIO: UNA APLICACIÓN A LA UNIVERSIDAD DE IBAGUÉ (COLOMBIA)

OpenAIRE

MORENO DE CASTRO, BLANCA ASTRID; CALDERÓN GARCÍA, MARÍA HAYDÉE

2017-01-01

Aportes académicos señalan que el consumidor es el actor más importante en la co-creación de valor, pero pocos estudios se han centrado en descubrir y comprobar la influencia de los comportamientos del consumidor que co-crea valor en su satisfacción. En consecuencia, en este artículo se contrasta esta relación en el contexto universitario, para lo cual se plantea un modelo relacional con las variables: comportamiento del consumidor en la co-creación de valor y satisfacción. Dicho modelo se ap...

Cation Exchange Efficiency Of Modified Bentonite Using In-Situ GAMMA Radiation Polymerization Of Acrylic Acid Or Acrylamide

International Nuclear Information System (INIS)

ISMAIL, S.A.; FALAZI, B.

2009-01-01

Modified bentonites as cation exchangers were prepared by treating raw bentonite with 3N NaOH at 95 0 C followed by in-situ polymerization using gamma irradiation as well as hydrogen peroxide initiation of acrylic acid or acrylamide in the matrix.Water swelling and acid capacity were determined and cation exchange capacity for Cu 2+ , Ni 2+ and Co 2+ was evaluated. It has been found that catiexchange capacity of treated bentonite was increased as result of formed polyacrylic acid and polyacrylamide in the matrix. In case of acrylic acid, the maximum cation exchange capacities of 3.5, 3.1 and 2.5 mg equivalent/g were determined for Cu 2+ , Ni 2+ and Co 2+ , respectively, and for acrylamide, the corresponding capacities were 2.9, 2.8 and 2.6 mg equivalent/g, respectively. Water swelling was found to be associated with holding large amounts of water, for instance, 49 g of water was sorbed per one gram of the sodium salt form of polyacrylic acid in bentonite matrix, in other words the degree of swelling in water achieved 4500%.

De la autoformación como práctica instituyente en las metrópolis postfordistas

OpenAIRE

Miquel Bartual, María José

2013-01-01

A través de un recorrido teórico- práctico, nos proponemos investigar cómo, en el contexto de las metrópolis postfordistas, determinados procesos de autoformación pueden llevar a transformaciones sociales en el ámbito político. En esta premisa, analizaremos previamente si la autoformación constituye en sí un cuestionamiento de los lugares asignados en la redistribución de los saberes, vinculada a procesos de cooperación social y resistencia, así como a la generación de instituciones del comú...

Synthesis of thermoresponsive poly(N-isopropylacrylamide) brush on silicon wafer surface via atom transfer radical polymerization

Energy Technology Data Exchange (ETDEWEB)

Turan, Eylem; Demirci, Serkan [Department of Chemistry, Faculty of Art and Science, Gazi University, 06500 Besevler, Ankara (Turkey); Caykara, Tuncer, E-mail: caykara@gazi.edu.t [Department of Chemistry, Faculty of Art and Science, Gazi University, 06500 Besevler, Ankara (Turkey)

2010-08-31

Thermoresponsive poly(N-isopropylacrylamide) [poly(NIPAM)] brush on silicon wafer surface was prepared by combining the self-assembled monolayer of initiator and atom transfer radical polymerization (ATRP). The resulting polymer brush was characterized by in situ reflectance Fourier transform infrared spectroscopy, atomic force microscopy and ellipsometry techniques. Gel permeation chromatography determination of the number-average molecular weight and polydispersity index of the brush detached from the silicon wafer surface suggested that the surface-initiated ATRP method can provide relatively homogeneous polymer brush. Contact angle measurements exhibited a two-stage increase upon heating over the board temperature range 25-45 {sup o}C, which is in contrast to the fact that free poly(NIPAM) homopolymer in aqueous solution exhibits a phase transition at ca. 34 {sup o}C within a narrow temperature range. The first de-wetting transition takes place at 27 {sup o}C, which can be tentatively attributed to the n-cluster induced collapse of the inner region of poly(NIPAM) brush close to the silicon surface; the second de-wetting transition occurs at 38 {sup o}C, which can be attributed to the outer region of poly(NIPAM) brush, possessing much lower chain density compared to that of the inner part.

Theoretical and experimental assessment of the kinetic properties of N-isopropyl-p-[{sup 123}I]iodoamphetamine in the human brain

Energy Technology Data Exchange (ETDEWEB)

Mori, Kentaro; Nakajima, Keiji; Maeda, Minoru [Juntendo Univ., Shizuoka (Japan). Izunagaoka Hospital

1993-12-01

The effect of the loss of radioactivity from the human brain on the measurement of regional cerebral blood flow (rCBF) using N-isopropyl-p-[{sup 123}I]iodoamphetamine (IMP) was evaluated by measuring rCBF in 10 normal male volunteers from 0.5 to 30 minutes after intravenous administration. rCBF was calculated by the operational equation, which assumes no product loss. Brain tissue and arterial blood concentration data were plotted according to a multiple-time/graphic evaluation technique. Data were fitted to the kinetic three-compartment model to estimate four kinetic rate constants to evaluate activity loss from the brain. These studies showed that loss of activity from the brain is negligible during the first 5 minutes, but after 7.5 minutes the loss becomes significantly higher with time. The present study corroborates the necessity for using single photon emission computed tomographic images measured within 5 minutes of IMP injection to quantify rCBF. (author).

Evaluation of cerebral perfusion imaging with N-isopropyl-p-[{sup 123}I]iodoamphetamine (IMP) in the cases of antiphospholipid syndrome

Energy Technology Data Exchange (ETDEWEB)

Kato, Toru; Nanbu, Ichiro; Tohyama, Junko; Ohba, Satoru [Nagoya City Univ. (Japan). Faculty of Medicine

1995-01-01

Five cases of antiphospholipid syndrome with mild headache, but without any neurological deficits and abnormal findings by CT and MRI, were examined by cerebral blood perfusion SPECT using N-isopropyl-p-[{sup 123}I] iodoamphetamine (IMP). Although three cases were performed quantification of cerebral blood flow with a microsphere method simultaneously, their values were within normal limits. Two of them showed focal low perfusion areas. One case had relatively low perfusion areas in the bilateral occipital lobes and the right temporal lobe, which improved after treatment. One of two had low perfusion in the bilateral occipital lobes. Other three cases only showed ununiformity of radioisotope uptake on the cerebral blood perfusion SPECT. Low perfusion areas in antiphospholipid syndrome might be caused by microarterial thrombosis, microvenous thrombosis or spasms, although they could be reversible. As early irreversible progress of cerebral blood flow, cerebral blood flow SPECT should be performed in cases of antiphospholipid syndrome with neurological complainments. (author).

Radiation curing of intelligent coating for controlled release and permeation

International Nuclear Information System (INIS)

Nakayama, Hiroshi; Kaetsu, Isao; Uchida, Kumao; Sakata, Shoei; Tougou, Kazuhide; Hara, Takamichi; Matsubara, Yoshio

2002-01-01

Intelligent membranes for pH and temperature-responsive drug releases were developed by coating and curing of polymer-drug composite film with electrolyte or N-isopropyl acrylamide curable mixture. It was proved that those intelligent membranes showed the stimule-sensitive and responsive release functions and could be produced efficiently by radiation curing processing with a conveyer system

External Electric Field Effects on Excited-State Intramolecular Proton Transfer in 4'-N,N-Dimethylamino-3-hydroxyflavone in Poly(methyl methacrylate) Films.

Science.gov (United States)

Furukawa, Kazuki; Hino, Kazuyuki; Yamamoto, Norifumi; Awasthi, Kamlesh; Nakabayashi, Takakazu; Ohta, Nobuhiro; Sekiya, Hiroshi

2015-09-17

The external electric field effects on the steady-state electronic spectra and excited-state dynamics were investigated for 4'-N,N-(dimethylamino)-3-hydroxyflavone (DMHF) in a poly(methyl methacrylate) (PMMA) film. In the steady-state spectrum, dual emission was observed from the excited states of the normal (N*) and tautomer (T*) forms. Application of an external electric field of 1.0 MV·cm(-1) enhanced the N* emission and reduced the T* emission, indicating that the external electric field suppressed the excited-state intramolecular proton transfer (ESIPT). The fluorescence decay profiles were measured for the N* and T* forms. The change in the emission intensity ratio N*/T* induced by the external electric field is dominated by ESIPT from the Franck-Condon excited state of the N* form and vibrational cooling in potential wells of the N* and T* forms occurring within tens of picoseconds. Three manifolds of fluorescent states were identified for both the N* and T* forms. The excited-state dynamics of DMHF in PMMA films has been found to be very different from that in solution due to intermolecular interactions in a rigid environment.

Distribution of N-isopropyl-p-(I-123)iodoamphetamine among the peripheral blood components

International Nuclear Information System (INIS)

Kumazaki, Satoshi; Oriuchi, Noboru; Tomiyoshi, Katsumi; Inoue, Tomio; Sasaki, Yasuhito.

1990-01-01

With the purpose to clarify dynamics of N-isopropyl-p-[I-123]iodoamphetamine (I-123 IMP) in the blood stream its binding to the peripheral blood components was determined by in vitro experiment. I-123 IMP was added to the peripheral venous blood obtained from healthy volunteers to be incubated for different length of time (0-30 min) at 37deg C. The blood was then separated into blood cells and plasma. From the latter platelet rich plasma were separated. Radioactivity in each blood component was counted in a well type scintillation counter respectively. To evaluate the affinity of I-123 IMP to red blood cell the component containing blood cells were washed repeatedly with salines. It was found that the fraction of radioactivity in the blood cell component was 68.0±6.3% (m±1 S.D.), which was higher than that in the plasma (32.0%±6.3%). The radioactivity in the platelet-rich plasma was only 1.7±1.1% of the total I-123 IMP activity. This percentage did not change by the incubation time. When Tc-99m DTPA was incubated with blood, radioactivity in the blood cell component was only 22.5%, which is further lowered by 32±2.1% after each washing to reach 6.8% after three times washing. In contrast the radioactivity of I-123 IMP in blood cell component remained as high as 31.1% after eight times washing. Almost constant fraction (8.20±0.57%) of radioactivity was freed into supernate by each washing. These findings suggest that a certain specific binding mechanism is involved in the binding of I-123 IMP to red blood cells. (author)

First-principles investigation of CO adsorption on pristine, C-doped and N-vacancy defected hexagonal AlN nanosheets

Science.gov (United States)

Ouyang, Tianhong; Qian, Zhao; Ahuja, Rajeev; Liu, Xiangfa

2018-05-01

The optimized atomic structures, energetics and electronic structures of toxic gas CO adsorption systems on pristine, C-doped and N-vacancy defected h-AlN nanosheets respectively have been investigated using Density functional theory (DFT-D2 method) to explore their potential gas detection or sensing capabilities. It is found that both the C-doping and the N-vacancy defect improve the CO adsorption energies of AlN nanosheet (from pure -3.847 eV to -5.192 eV and -4.959 eV). The absolute value of the system band gap change induced by adsorption of CO can be scaled up to 2.558 eV or 1.296 eV after C-doping or N-vacancy design respectively, which is evidently larger than the value of 0.350 eV for pristine material and will benefit the robustness of electronic signals in potential gas detection. Charge transfer mechanisms between CO and the AlN nanosheet have been presented by the Bader charge and differential charge density analysis to explore the deep origin of the underlying electronic structure changes. This theoretical study is proposed to predict and understand the CO adsorption properties of the pristine and defected h-AlN nanosheets and would help to guide experimentalists to develop better AlN-based two-dimensional materials for efficient gas detection or sensing applications in the future.

Synthesis of Cassava Waste Pulp-Acrylamide Super Absorbent: Effect of Initiator and Cross-Linker Concentration

Directory of Open Access Journals (Sweden)

Zainal Alim Mas’ud

2013-05-01

Full Text Available Cassava waste pulp (CWP contains high carbohydrates that can be modified into super absorbent polymer (SAP through grafting and cross-linking copolymerization. Acrylamide (AM was grafted onto CWP with ammonium persulfate (APS as the initiator and N,N'-methylene-bis-acrylamide (MBA as the cross-linker under atmospheric nitrogen. The effect of APS and MBA concentrations on water absorption capacity of saponified SAP was studied, while the evaluation of grafting ratio (GR and grafting efficiency (GRE was conducted on unsaponified SAP. The grafting success was indicated by the occurrence of IR peaks at wave numbers of 573, 765, 858, and 1667 cm-1. In the saponified SAP, the very intense characteristic band at 1562 cm-1 is due to C=O asymmetric stretching in the carboxylate anion. Saponification increases significantly water absorption capacity compared to that of unsaponified SAP (from 39.79 g/g to 578.23 g/g. The highest water absorption capacity is reached at 0.74% APS and 0.09% MBA. The percentage of GRE and GR tends to increase with increasing APS concentration until reaching the highest value and then decreases. Effect of MBA concentration on water absorption capacity, GR, and on GRE is similar to the effect of initiator concentration on GR and GRE.

Structure-property relationships for n-alkyl-isocyanate-containing polymers

Science.gov (United States)

Aronson, Carl Lawrence

Poly(n-hexyl isocyanate) (PHIC), poly(n-butyl-isocyanate) (PBIC), poly(n-butyl-co-cyclohexyl isocyanate) (PBCHIC), poly(n-hexyl isocyanate-b-isoprene) (HI), poly(n-butyl isocyanate-b-isoprene) (BI) and poly(n-hexyl isocyanate-b-isoprene- b-styrene) (MS) were synthesized and characterized with respect to composition, molecular Weight and polydispersity. PHIC, HI and HIS were found to be lyotropic liquid crystalline whereas PBIC, PBCHIC and BI were found to be non-lyotropic. A lyotropic-nematic liquid crystalline phase diagram was determined for the PHIC/xylene system. A novel and reversible electric-field-induced biphasic-paranematic phase transition was found for the PHIC/xylene system from the dynamics of topological defects. The electric-field-induced phase diagram for PHIC/xylene agreed with the theoretically predicted field-induced phase diagram of Khokhlov and Semenov for semiflexible-persistent polymers. The dielectric characteristics, steady-state electrically induced birefringence and steady-state electroheological (ER) activity of PHIC, PBIC and PBCHIC solutions were compared as a function of polymer concentration. The role of lyotropic liquid crystalline ordering in the functional ER mechanism of poly( n-hexyl isocyanate) solutions is presented. PBCHIC was found to thermally decompose by a first-order rate process which became slower with increasing cyclohexyl isocyanate content from thermal gravimetric analysis. Competition between monomer dissociation and degradative trimerization as well as a non-alternating sequence distribution were determined for PBCHIC from direct pyrolysis/mass spectrometry. The Arrhenius activation energy, pre-exponential factor and entropy for diffusion and evaporation of xylene from PHIC, were found to be functions of initial polymer concentration whereas the intrinsic diffusion coefficient of the solvent was found to be independent of initial polymer concentration. The cross polarized/magic angle spinning solid state 13C

Poly(aniline-co-m-aminobenzoic acid) deposited on poly(vinyl ...

Indian Academy of Sciences (India)

Abstract. In this work, we have deposited poly(aniline-co-m-aminobenzoic acid) on poly(vinyl alcohol) (PVA) by in situ ... along the polyaniline (PANI) chain results in self dop- ing of PANI and ..... The value of electrical conductivity is found to be ...

Linear free energy relationships in heterogeneous catalysis--13. The dehydration of aliphatic alcohols over silica-alumina. [N-butyl alcohol, sec. -butyl or isopropyl alcohol, tert. -butyl alcolol

Energy Technology Data Exchange (ETDEWEB)

Take, J; Matsumoto, T; Yoneda, Y

1978-01-01

The dehydration of n-butyl alcohol at 120/sup 0/-166/sup 0/C, sec.-butyl or isopropyl alcohol at 100/sup 0/-145/sup 0/C, and tert.-butyl alcohol at 54/sup 0/-80/sup 0/C, over silica/alumina catalyst was zero order in alcohol at 0.01-0.1 atm, and the activation energies were 35.3, 31.7, 32.0, and 29.9 kcal/mol, respectively. The zero-order rate constants were mainly affected by the activation energies since the preexponential factors varied little except for tert.-butyl alcohol. A linear relationship was found between the activation energy or the logarithm of the zero-order rate constant and the heterolytic bond dissociation energy for the carbon-oxygen bond in alcohols D(R/sup +/OH/sup -/). The activation energy increased and the rate constant decreased with increasing D(R/sup +/OH/sup -/). The results indicate that dehydration is E1 over this catalyst, but a similar correlation was observed based on published data for dehydration over alumina, which follows an E2 mechanism, indicating that heterolytic cleavage of the C-O bond is rate-determining in both mechanisms.

New design of N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) lung imaging in the patient with lung cancer

International Nuclear Information System (INIS)

Tanaka, Eiko; Mishima, Michiaki; Kawakami, Kenzo; Sakai, Naoki; Sugiura, Naoharu; Ohi, Motoharu; Kuno, Kenshi; Taniguchi, Takashi; Itoh, Harumi.

1995-01-01

N-isopropyl-p-[ 123 I]iodoamphetamine ( 123 I-IMP) was injected intravenously into primary non small cell lung carcinoma patients (n=17). The average pixel count ratios of the cancerous area to the whole lung was measured in the initial and delayed images. In the initial image, this ratio was less than 1.0 for the entire group of patients, and was thought to reflect decreased blood flow in the cancerous tissues. The rate of counts within a ROI in the delayed image to counts in the same ROI in the initial image was also calculated and called the remain rate. The remain rate (delayed count/initial count) was significantly higher in the cancerous area than in the whole lung (0.65±0.30, median 0.62, 0.38±0.05, median 0.38, p<0.01). This observation was thought to be due to a relative decrease in the blood flow and the accumulation of IMP, which forms pools within the alveolar spaces of the cancerous areas. The image prepared with the remain rate revealed a hot image in the cancerous regions, even when this was not apparent in the delayed image. The remain rate image may therefore be useful in the identification of cancerous areas in lung tissue if it is used in comparison with the initial image. (author)

Characterization of trypsin-derived peptides acrylamide-adducted hemoglobin

International Nuclear Information System (INIS)

Springer, D.L.; Goheen, S.C.; Edmonds, C.G.; McCulloch, M.; Sylvester, D.M.; Sander, C.; Bull, R.J.

1991-01-01

Even though there are a number of sources for human exposure to acrylamide, reliable biomarkers of exposure are not available. In an effort to develop such a biomarker, the authors are characterizing peptides derived from trypsin digests of acrylamide-adducted hemoglobin. For this, radiolabeled acrylamide was incubated with this, radiolabeled acrylamide was incubated with purified human hemoglobin (Ao) and decomposition products removed by dialysis. When the adducted hemoglobin was separated by reverse-phase HPLC, radioactivity eluted with the α and β subunits, suggesting covalent binding. Digestion of individual subunits with trypsin followed by reverse phase HPLC, indicated that most of the radioactivity associated with the α subunit co-eluted with a single peptide. Similar results were observed for the β subunit except that significant amounts of radioactivity eluted with the solvent front, suggesting that radioactivity was released by trypsin digestion. Currently, these preparation are under further characterization by electrospray ionization mass spectrometry. This approach will aid in the identification of the adducted will aid in the identification of the adducted peptide and subsequent preparation of an acrylamide-specific antibody

Regional cerebral blood flow measurement using N-isopropyl-p-[123I] iodoamphetamine and rotating gamma camera emission computed tomography

International Nuclear Information System (INIS)

Matsuda, Hiroshi; Seki, Hiroyasu; Ishida, Hiroko

1985-01-01

Thirty-one regional cerebral blood flow (rCBF) measurements were performed on 26 patients with cerebrovascular accidents using N-Isopropyl-p-[ 123 I] Iodoamphetamine ( 123 I-IMP) and rotating gamma camera emission computed tomography (ECT). The equation for determining rCBF is as follows: F=100.R.Cb/(N.A), where F is rCBF in ml/100 g/min., R is the constant withdrawal rate of arterial blood in ml/min., Cb is the brain activity concentration in μCi/g, A is the total activity (5 min.) in the withdrawal arterial whole blood in μCi and N is the fraction of A that is true tracer activity (0.75). In determining Cb at 5 min. after injection, reconstructed counts from 35 min. to 59 min. were corrected to represent those from 4 min. to 5 min. with the use of time activity curve for the entire brain immediately after injection to 30 min. Reconstructed counts of central region in tomographic image were corrected 118% of the obtained values from the result of the countingrate ratio between peripheral and central regions of interests obtained from phantom study. Brain mean blood flow values were distributed from 11 to 39 ml/100 g/min. In 119 cortical regions obtained from 11 measurements in 9 patients, there was a significant correlation (r=0.41, p 123 I-IMP and rotating gamma camera ECT and those from 133 Xe inhalation method. rCBF measurement using 123 I-IMP and rotating gamma camera ECT is not only relatively noninvasive measurement for the entire brain but also three-dimensional evaluation. Besides, it is superior in spatial resolution and accuracy to conventional 133 Xe clearance method. (author)

Thermophysical property characterization of tris(hydroxymethyl)aminomethane

International Nuclear Information System (INIS)

Soriano, Allan N.; Cabahug, Denise Irene V.; Li Menghui

2011-01-01

In this present work, a thermophysical property characterization of aqueous solution of tris(hydroxymethyl)aminomethane (TRIS), a biological buffer, was done. The investigated properties were refractive index (n), density (ρ), and electrolytic conductivity (κ). These properties were measured for temperatures up to 353.15 K (at normal atmospheric condition) and for the entire composition range where TRIS is still soluble in water. The measured properties were reported as functions of temperature and composition. A modified form of the Vogel-Tamman-Fulcher equation which leads to an Arrhenius-type asymptotic exponential function was used to generally correlate the temperature and compositional dependence of the considered properties and satisfactory results were obtained.

Contribución a la historia de Coín : el topónimo "malara"

OpenAIRE

López Beltrán, María Teresa

2010-01-01

En los fondos notariales del Archivo Histórico Provincial de Málaga se conserva el testamento otorgado por Antón de Malara, vecino de la villa de Coín, de cuyo apellido y linaje ha quedado memoria histórica tanto en el nombre de una pequeña calle del casco histórico de la villa como en el de uno de los partidos rurales que estructuran el término municipal de Coín. The will made by Anton de Malara is contained in the notarial records of Malaga Provincial Historical Archive. He was resident ...

Demonstration and quantitation of pharmacological inhibition of pulmonary uptake of N-isopropyl- sup 123 I-p-Iodoamphetamine by propanolol

Energy Technology Data Exchange (ETDEWEB)

Akber, S.F. (California Univ., Los Angeles (USA). Nuclear Medicine Div.)

1989-06-01

The first-pass pulmonary extraction values of N-Isopropyl-{sup 123}I-p-Iodoamphetamine ({sup 123}I-IMP) in pretreated dogs decreases from 90 to 62% as the amount of propranolol increases from 0 to 20 mg. The first-pass pulmonary extraction values of {sup 123}I-IMP in dogs with a simultaneous bolus injection of propranolol decreases from 90 to 62% as the amount of propranolol increases from 0 to 10 mg. The pulmonary extraction of {sup 123}I-IMP with a simultaneous bolus injection of ketamine and {sup 123}I-IMP decreases from 90 to 64% as the ketamine dose increases from 0 to 100 mg. These results suggest that the pulmonary uptake of {sup 123}I-IMP may be at least partially mediated by receptors. They also indicate that endothelial metabolic cell function may be a useful index of early lung pathology. Furthermore, studies of the degree of lung uptake may be a sensitive index of pathologic states in which alterations of amine binding sites have occurred. (orig.).

A new graphic method for evaluation of distribution volume on N-isopropyl-p-[[sup 123]I]iodoamphetamine (IMP) SPECT

Energy Technology Data Exchange (ETDEWEB)

Odano, Ikuo; Takahashi, Naoya; Ohtaki, Hiroh; Noguchi, Eikichi; Hatano, Masayoshi; Yamasaki, Yoshihiro; Nishihara, Mamiko [Niigata Univ. (Japan). School of Medicine; Ohkubo, Masaki; Yokoi, Takashi

1993-10-01

We developed a new graphic method using N-isopropyl-p-[[sup 123]I]iodoamphetamine (IMP) and SPECT of the brain, the graph on which all three parameters, cerebral blood flow, distribution volume (V[sub d]) and delayed count to early count ratio (Delayed/Early ratio), were able to be evaluated simultaneously. The kinetics of [sup 123]I-IMP in the brain was analyzed by a 2-compartment model, and a standard input function was prepared by averaging the time activity curves of [sup 123]I-IMP in arterial blood on 6 patients with small cerebral infarction etc. including 2 normal controls. Being applied this method to the differential diagnosis between Parkinson's disease and progressive supranuclear palsy, we were able to differentiate both with a glance, because the distribution volume of the frontal lobe significantly decreased in Parkinson's disease (Mean[+-]SD; 26[+-]6 ml/g). This method was clinically useful. We think that the distribution volume of [sup 123]I-IMP may reflect its retention mechanism in the brain, and the values are related to amine, especially to dopamine receptors and its metabolism. (author).

Modelo de cuantificación de las emisiones de CO2 producidas en edificación derivadas de los recursos materiales consumidos en su ejecución

Directory of Open Access Journals (Sweden)

Olivares, M.

2012-09-01

Full Text Available Research in this paper focuses on the generation of a model to quantify CO2 emissions in the implementation of a typical building block for affordable residential housing, derived from the manufacturing process of the materials used in its construction. The identification and quantification of building materials consumed, will reveal the environmental impact of producing the type defined by one of the indicators most relevant environmental impact associated with weight per m2 of construction, such as CO2 emissions resulting from manufacturing process of the construction materials used in its implementation. Its practical application to a set of ten projects located in Seville implementation, will provide conclusive data on the quantification of CO2 emissions in its implementation by identifying the greatest environmental impact.La investigación realizada en el presente trabajo plantea la generación de un modelo de cuantificación de las emisiones de CO2 producidas en la ejecución del modelo constructivo habitual definido como el bloque residencial destinado a viviendas de protección oficial, derivadas del proceso de fabricación de los recursos materiales empleados en su ejecución. La identificación y cuantificación de los materiales de construcción consumidos, permitirá conocer el impacto medioambiental que produce la tipología definida, a través de uno de los indicadores de impacto ambiental más relevantes asociados al peso por m2 de construcción, como son las emisiones de CO2 derivadas del proceso de fabricación de los materiales de construcción empleados en su ejecución. Su aplicación práctica a un conjunto de diez proyectos de ejecución ubicados en Sevilla, proporcionará datos concluyentes sobre la cuantificación de las emisiones de CO2 producidas en su ejecución, identificando los de mayor impacto ambiental.

Gasificación con CO2 de carbonizados de aserrín de Pinus caribaea Morelet var. cariba

OpenAIRE

F. Márquez-Montesino; T. Cordero-Alcántara; J. Rodríguez-Mirasol; J. J. Rodríguez-Jiménez

2004-01-01

Dada la importancia del estudio de la reactividad de los carbones con el fin de estudiar su activación, se desarrolló la gasificación con CO2 de un carbón obtenido de aserrín de Pinus caribaea. Los ensayos termogravimétricos se realizaron en un sistema modular de CI Electronics, las temperaturas de gasificación escogidas fueron 750, 775, 800 y 825 °C. Para calcular los valores de reactividad normalizada, se determinó el área de superficie por adsorción de CO2 a 273 K, en un equipo Au...

Formation cross section of iron-60 with reactor neutrons in 59Fe(n, γ)60Fe reaction

International Nuclear Information System (INIS)

Sato, T.; Suzuki, T.

1993-01-01

Ingrowth of 60 Co radioactivity in an iron sample irradiated in a nuclear reactor has been measured for determination of formation cross section of 60 Fe in the 59 Fe(n, γ) 60 Fe reaction with reactor neutrons. After 5 years cooling, the irradiated iron was purified from 60 Co and other radioactive nuclides by an anion exchange separation method and isopropyl ether extraction in hydrochloric acid. The amount of 60 Co ingrowth was measured by γ-spectrometry using a Ge-detector coupled to a multichannel pulse height analyzer 4 years after the purification of iron. Neutron flux of the irradiation position was calculated from the amount of 55 Fe produced. The observed value of 12.5 ± 2.8 barn is slightly greater than reported value for burnup cross section of 59 Fe(n, x)X, where x refers γ, α, d, p and 2n, and X is any nuclide produced by the above reactions. (author) 8 refs.; 2 tabs

Biodegradation of poly(lactic acid, poly(hydroxybutyrate-co-hydroxyvalerate, poly(butylene succinate and poly(butylene adipate-co-terephthalate under anaerobic and oxygen limited thermophilic conditions

Directory of Open Access Journals (Sweden)

Jutakan Boonmee

2016-01-01

Full Text Available In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid (PLA, poly(hydroxybutyrate-co-hydroxyvalerate (PHBV, poly(butylene succinate (PBS, and poly(butylene adipate-co-terephthalate (PBAT were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of biodegradation after 75 days was investigated by weight loss determination, visual examination, and surface appearance by scanning electronic microscopy (SEM. Under both anaerobic and oxygen limited conditions, the complete degradation (100% weight loss was found only in PHBV after 75 days. The plastic degradations were ranked in the order of PHBV> PLA> PBS> PBAT. The percentage of weight losses were significantly different at p ≤ 0.05. However, for all studied plastics, the degradation under anaerobic and oxygen limited conditions did not significantly different at 95% confidence.

N-heterocyclic carbene copper(I) catalysed N-methylation of amines using CO2

KAUST Repository

Santoro, Orlando

2015-09-30

The N-methylation of amines using CO2 and PhSiH3 as source of CH3 was efficiently performed using a N-heterocyclic carbene copper(I) complex. The methodology was found compatible with aromatic and aliphatic primary and secondary amines. Synthetic and computational studies have been carried out to support the proposed reaction mechanism for this transformation.

N-heterocyclic carbene copper(I) catalysed N-methylation of amines using CO2

KAUST Repository

Santoro, Orlando; Lazreg, Faï ma; Minenkov, Yury; Cavallo, Luigi; Cazin, Catherine S. J.

2015-01-01

The N-methylation of amines using CO2 and PhSiH3 as source of CH3 was efficiently performed using a N-heterocyclic carbene copper(I) complex. The methodology was found compatible with aromatic and aliphatic primary and secondary amines. Synthetic and computational studies have been carried out to support the proposed reaction mechanism for this transformation.

Electron capture into the n = 3 states of hydrogen by proton impact on CO, CO2, and N2O

International Nuclear Information System (INIS)

Loyd, D.H.; Dawson, H.R.

1979-01-01

Absolute cross sections for electron capture into the 3s, 3p, and 3d states of hydrogen have been measured for 2.2--8.2-keV proton impact on CO, CO 2 , and N 2 O. The relative magnitudes of the 3s, 3p, and 3d cross sections for CO are very similar to cross sections previously measured for elemental gases. The CO 2 and N 2 O cross sections have a very different relative distribution among the 3s, 3p, and 3d states compared to all other gases studied in this laboratory, with the 3p cross section being so small that only an estimate of the upper limit to the cross section was possible

Thermally reversible hydrogels based on 2-methoxyethylacrylate (MOEA) as drug delivery systems

Energy Technology Data Exchange (ETDEWEB)

Martellini, Flavia; Mei, Lucia Helena [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Quimica. Dept. de Polimeros; Moraes, Daniel T.F. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo (Brazil); Balino, Jorge Luis [Centro Atomico Bariloche, RN (Argentina). Inst. Balseiro; Carenza, Mario [Consiglio Nazionale delle Ricerche (CNR), Padova (Italy). Sezione di Lenaro. Ist. di Fotochimica e Radiazioni d' Alta Energia

2000-07-01

Hydrogels of poly(N,N-dimethylacrylamide-co-2-methoxy ethylacrylate) and poly(acrylamide-co-2-methoxy ethylacrylate) have been synthesised by radiation polymerization in dimethylformamide solution with trimethylolpropane trimethacrylate as a cross linker. In this work, it is reported the investigations about the release in vitro of gentamicin sulphate, an antibiotic entrapped in the hydrogels, in aqueous solutions. The result indicate that the release occurs practically in the first 24 h, the release rate is constant over a period of 35 hours and without displaying any significant burst effect. The evidence observed also indicates that the solute transport in the beginning of release is controlled by Fickian diffusion and fractional release of gentamicin is initially linear when plotted against the square root of time, as expected for a Fickian process. (author)

Thermally reversible hydrogels based on 2-methoxyethylacrylate (MOEA) as drug delivery systems

International Nuclear Information System (INIS)

Martellini, Flavia; Mei, Lucia Helena; Balino, Jorge Luis; Carenza, Mario

2000-01-01

Hydrogels of poly(N,N-dimethylacrylamide-co-2-methoxy ethylacrylate) and poly(acrylamide-co-2-methoxy ethylacrylate) have been synthesised by radiation polymerization in dimethylformamide solution with trimethylolpropane trimethacrylate as a cross linker. In this work, it is reported the investigations about the release in vitro of gentamicin sulphate, an antibiotic entrapped in the hydrogels, in aqueous solutions. The result indicate that the release occurs practically in the first 24 h, the release rate is constant over a period of 35 hours and without displaying any significant burst effect. The evidence observed also indicates that the solute transport in the beginning of release is controlled by Fickian diffusion and fractional release of gentamicin is initially linear when plotted against the square root of time, as expected for a Fickian process. (author)

Poly(N-isopropylacrylamide and Copolymers: A Review on Recent Progresses in Biomedical Applications

Directory of Open Access Journals (Sweden)

Sonia Lanzalaco

2017-10-01

Full Text Available The innate ability of poly(N-isopropylacrylamide (PNIPAAm thermo-responsive hydrogel to copolymerize and to graft synthetic polymers and biomolecules, in conjunction with the highly controlled methods of radical polymerization which are now available, have expedited the widespread number of papers published in the last decade—especially in the biomedical field. Therefore, PNIPAAm-based hydrogels are extensively investigated for applications on the controlled delivery of active molecules, in self-healing materials, tissue engineering, regenerative medicine, or in the smart encapsulation of cells. The most promising polymers for biodegradability enhancement of PNIPAAm hydrogels are probably poly(ethylene glycol (PEG and/or poly(ε-caprolactone (PCL, whereas the biocompatibility is mostly achieved with biopolymers. Ultimately, advances in three-dimensional bioprinting technology would contribute to the design of new devices and medical tools with thermal stimuli response needs, fabricated with PNIPAAm hydrogels.

Determination of the Thermodynamic Properties of Poly [2-(3-phenyl-3-methylcyclobutyl)-2-hydroxyethyl methacrylate-co-methacrylic acid] at Infinite Dilution by Inverse Gas Chromatography

OpenAIRE

KAYA, İsmet

2014-01-01

Some thermodynamic quantities were obtained for the interactions of poly [2-(3-phenyl -3- methylcyclobutyl)-2-hydroxyethyl methacrylate-co-methacrylic acid] Poly (PCHEMA-co-MA) with alcohols, ketones, acetates, aromatics and n-alkanes by inverse gas chromatography in the temperature range of 150-180oC. The specific retention volumes, Vgo, weight fraction activity coefficients of solute probes at infinite dilution, W1\\infty and Flory-Huggins thermodynamic interaction parameters, c12...

Synthesis of porous poly(acrylamide hydrogels using calcium carbonate and its application for slow release of potassium nitrate

Directory of Open Access Journals (Sweden)

2009-05-01

Full Text Available Porous poly(acrylamide was synthesized using calcium carbonate microparticles and subsequent acid treatment to remove the calcium carbonate. Methylenebisacrylamide and ammonium persulfate/sodium metabisulfite were used as crosslinking agent and redox initiator, respectively. The porous structure of resulted hydrogels was confirmed using SEM micrographs. The effect of methylenebisacrylamide concentration and calcium carbonate amount on the swelling of the hydrogels was investigated. The results showed that the effect of methylenebisacrylamide and calcium carbonate variables on the swelling is reverse. The hydrogels were subsequently utilized for the loading of potassium nitrate. Potassium nitrate as active agent was loaded into hydrogels and subsequently the release of this active agent was investigated. In these series of investigation, the effect of content of loading, methylenebisacrylamide and calcium carbonate amount on the release of potassium nitrate from hydrogels was investigated.

Explaining the doubling of N2 O emissions under elevated CO2 in the Giessen FACE via in-field 15 N tracing.

Science.gov (United States)

Moser, Gerald; Gorenflo, André; Brenzinger, Kristof; Keidel, Lisa; Braker, Gesche; Marhan, Sven; Clough, Tim J; Müller, Christoph

2018-03-23

Rising atmospheric CO 2 concentrations are expected to increase nitrous oxide (N 2 O) emissions from soils via changes in microbial nitrogen (N) transformations. Several studies have shown that N 2 O emission increases under elevated atmospheric CO 2 (eCO 2 ), but the underlying processes are not yet fully understood. Here, we present results showing changes in soil N transformation dynamics from the Giessen Free Air CO 2 Enrichment (GiFACE): a permanent grassland that has been exposed to eCO 2 , +20% relative to ambient concentrations (aCO 2 ), for 15 years. We applied in the field an ammonium-nitrate fertilizer solution, in which either ammonium (NH4+) or nitrate (NO3-) was labelled with 15 N. The simultaneous gross N transformation rates were analysed with a 15 N tracing model and a solver method. The results confirmed that after 15 years of eCO 2 the N 2 O emissions under eCO 2 were still more than twofold higher than under aCO 2 . The tracing model results indicated that plant uptake of NH4+ did not differ between treatments, but uptake of NO3- was significantly reduced under eCO 2 . However, the NH4+ and NO3- availability increased slightly under eCO 2 . The N 2 O isotopic signature indicated that under eCO 2 the sources of the additional emissions, 8,407 μg N 2 O-N/m 2 during the first 58 days after labelling, were associated with NO3- reduction (+2.0%), NH4+ oxidation (+11.1%) and organic N oxidation (+86.9%). We presume that increased plant growth and root exudation under eCO 2 provided an additional source of bioavailable supply of energy that triggered as a priming effect the stimulation of microbial soil organic matter (SOM) mineralization and fostered the activity of the bacterial nitrite reductase. The resulting increase in incomplete denitrification and therefore an increased N 2 O:N 2 emission ratio, explains the doubling of N 2 O emissions. If this occurs over a wide area of grasslands in the future, this positive feedback reaction may

The use of new modified poly(acrylamide chelating resin with pendent benzothiazole groups containing donor atoms in the removal of heavy metal ions from aqueous solutions

Directory of Open Access Journals (Sweden)

Semmedu Selvaraj Kalaivani

2014-03-01

Full Text Available The adsorption studies of poly(6-(ethoxybenzothiazole acrylamide (PEBTA, for Cu(II and Zn(II metal ions removal from an aqueous solution have been investigated, as a function of solution pH, adsorbent dose, contact time, initial metal ion concentration and temperature. The chemical and structural characteristics of the adsorbent were determined by the FT-IR, 1H-NMR, TGA, SEM, and EDAX analysis. The maximum adsorption capacities of the adsorbent for Cu(II and Zn(II ions, as calculated from the Langmuir isotherm model, were 273.5 and 216.4 mg/g, respectively. The adsorption kinetic studies show that the adsorption of Cu(II and Zn(II ions onto PEBTA follows the pseudo second order kinetic model. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were also evaluated, and it has been found that the adsorption process is feasible, spontaneous and exothermic in nature. Desorption studies were carried out using 0.3 N HCl, and it revealed that the adsorbed Cu(II and Zn(II ions can be easily removed. The adsorption–desorption process is reversible, and this indicates that PEBTA is an effective adsorbent for the removal of heavy metal ions from an aqueous medium.

N-Heterocyclic Olefins as Initiators for the Polymerization of (Meth)Acrylic Monomers: A Combined Experimental and Theoretical Approach

KAUST Repository

Naumann, Stefan

2017-08-25

The zwitterionic organopolymerization of four different acrylic monomers (N,N-dimethylacrylamide, methyl acrylate, methyl methacrylate and tert-butyl methacrylate) based on neutral initiators, so-called N-heterocyclic olefins (NHOs), is presented. Scope and underlying (deactivation-)mechanisms where studied in a combined experimental and computational effort. From a range of differently structured NHOs it emerged that imidazole-, in contrast to imidazoline- and benzimidazole-derivatives, readily polymerize the selected monomers. While the additive-free reactions proceed with a relatively low degree of control to yield largely atactic material, for the acrylamide the addition of LiCl as µ-type ligand has been shown to result in a rapid and quantitative monomer consumption. The thus generated poly(N,N-dimethyl acrylamide) was found to be highly isotactic (>90% isotactic dyads) with high molecular weight (Mn = 250 000 – 650 000 g/mol, ÐM = 1.3- 1.6). Complementing DFT calculations considered the zwitterionic chain growth with respect to competing side reactions, namely spirocycles and enamine formation. It was found that NHOs with unsaturated backbone better support the zwitterionic chain growth, with the spirocycles acting as dormant species that slow down but do not quench the polymerization process. Contrasting this, enamine formation irreversibly terminates the polymerization and is found to be energetically favored. This pathway can be blocked by introduction of substituents on the exocyclic carbon of the NHO, resulting in structures like 2-isopropylidene-1,3,4,5-tetramethylimidazoline (4) which consequently deliver the most controlled polymerizations. Finally, a good correlation of the initiation energy barrier with the buried volume (%VBur) and the Parr electrophilicity index is described, allowing for a quick and reliable screening of potential monomers based on these two readily accessible parameters.

Thermoresponsive polymer system based on poly(N-vinylcaprolactam) intended for local radiotherapy applications

Czech Academy of Sciences Publication Activity Database

Černoch, Peter; Černochová, Zulfiya; Kučka, Jan; Hrubý, Martin; Petrova, Svetlana; Štěpánek, Petr

2015-01-01

Roč. 98, April (2015), s. 7-12 ISSN 0969-8043 R&D Projects: GA MPO FR-TI4/625; GA MŠk(CZ) LH14079 Grant - others:AV ČR(CZ) M200501201 Program:M Institutional support: RVO:61389013 Keywords : poly(N-vinylcaprolactam) * tumor * brachytherapy Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.136, year: 2015

Enhanced CO{sub 2} capture on graphene via N, S dual-doping

Energy Technology Data Exchange (ETDEWEB)

Li, Jieyuan; Hou, Meiling [College of Architecture and Environment, Sichuan University (China); Chen, Yanqiu [Institute of New Energy and Low Carbon Technology, Sichuan University (China); Cen, Wanglai [Institute of New Energy and Low Carbon Technology, Sichuan University (China); National Engineering Research Center for Flue Gas Desulfurization (China); Chu, Yinghao, E-mail: chuyinghao@scu.edu.cn [College of Architecture and Environment, Sichuan University (China); National Engineering Research Center for Flue Gas Desulfurization (China); Yin, Shi, E-mail: yinshi_scu@foxmail.com [College of Architecture and Environment, Sichuan University (China)

2017-03-31

Highlights: • Sluggish conjugated π bonds of graphene should be weakened to promote adsorption activity. • A charge delivery channel along S → N → CO{sub 2} path should be prior responsible for the enhancement of CO{sub 2} capture on graphene. • Applicative temperature range of graphene-based adsorbents for CO{sub 2} capture is extend to about 100 °C via N, S dual-doping. - Abstract: N, S doped graphene-based materials have been recently recognized as promising adsorbents for CO{sub 2} capture, but understanding of the adsorption mechanism at the atomic level is still limited. Herein, the local structures and promotion mechanism of CO{sub 2} capture by N, S doped graphene were investigated by combining density functional theory and ab initio thermodynamics. A single vacancy defected graphene involving N, S dual-doping was found to be a superior adsorbent for CO{sub 2} capture under mild conditions (<100 °C, 1 atm). The enhanced CO{sub 2} adsorption performance should be ascribed to a charge delivery channel along the S → N → CO{sub 2} path, leading to extra charge transfer from graphene to CO{sub 2}. It is worth mentioning that the extra charge transfer was stimulated by the unique sp{sup 2} hybridization of pyridine N and further enhanced by S in N, S dual-doped graphene. A possible mechanism has been proposed to explain the high adsorption performance of CO{sub 2} by N, S dual-doped graphene, which offers insights for the design of new graphene-based adsorbents.

Influence of molar mass of polymer on the solvent activity for binary system of poly N-vinylcaprolactam and water

International Nuclear Information System (INIS)

Foruotan, Masumeh; Zarrabi, Mona

2009-01-01

The water activity in aqueous solution of poly N-vinyl caprolactam with different molecular weights is measured by isopiestic method at T = 308.15 K. The results show that water activity and vapour pressure of poly N-vinylcaprolactam solution increases with increasing the molecular weight. The Flory-Huggins model, the modified Flory-Huggins model and Freed Flory-Huggins equation + NRTL model are used for correlation of the experimental solvent activity. It is found that the Freed Flory-Huggins + NRTL model is better than the others

Defect formation and magnetic properties of Co-doped GaN crystal and nanowire

International Nuclear Information System (INIS)

Shi, Li-Bin; Liu, Jing-Jing; Fei, Ying

2013-01-01

Theoretical calculation based on density functional theory (DFT) and generalized gradient approximation (GGA) has been carried out in studying defect formation and magnetic properties of Co doped GaN crystal and nanowire (NW). Co does not exhibit site preference in GaN crystal. However, Co occupies preferably surface sites in GaN NW. Transition level of the defect is also investigated in GaN crystal. We also find that Co Ga (S) in NW does not produce spin polarization and Co Ga (B) produces spontaneous spin polarization. Ferromagnetic (FM) and antiferromagnetic (AFM) couplings are analyzed by six different configurations. The results show that AFM coupling is more stable than FM coupling for Co doped GaN crystal. It is also found from Co doped GaN NW calculation that the system remains FM stability for majority of the configurations. Magnetic properties in Co doped GaN crystal can be mediated by N and Ga vacancies. The FM and AFM stability can be explained by Co 3d energy level coupling

Natural co-infection of influenza A/H3N2 and A/H1N1pdm09 viruses resulting in a reassortant A/H3N2 virus.

Science.gov (United States)

Rith, Sareth; Chin, Savuth; Sar, Borann; Y, Phalla; Horm, Srey Viseth; Ly, Sovann; Buchy, Philippe; Dussart, Philippe; Horwood, Paul F

2015-12-01

Despite annual co-circulation of different subtypes of seasonal influenza, co-infections between different viruses are rarely detected. These co-infections can result in the emergence of reassortant progeny. We document the detection of an influenza co-infection, between influenza A/H3N2 with A/H1N1pdm09 viruses, which occurred in a 3 year old male in Cambodia during April 2014. Both viruses were detected in the patient at relatively high viral loads (as determined by real-time RT-PCR CT values), which is unusual for influenza co-infections. As reassortment can occur between co-infected influenza A strains we isolated plaque purified clonal viral populations from the clinical material of the patient infected with A/H3N2 and A/H1N1pdm09. Complete genome sequences were completed for 7 clonal viruses to determine if any reassorted viruses were generated during the influenza virus co-infection. Although most of the viral sequences were consistent with wild-type A/H3N2 or A/H1N1pdm09, one reassortant A/H3N2 virus was isolated which contained an A/H1N1pdm09 NS1 gene fragment. The reassortant virus was viable and able to infect cells, as judged by successful passage in MDCK cells, achieving a TCID50 of 10(4)/ml at passage number two. There is no evidence that the reassortant virus was transmitted further. The co-infection occurred during a period when co-circulation of A/H3N2 and A/H1N1pdm09 was detected in Cambodia. It is unclear how often influenza co-infections occur, but laboratories should consider influenza co-infections during routine surveillance activities. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Studies on the structure and thermal behaviour of poly(N-alkyl sesqui oxanes) base silicon resins; Estudos da estrutura e do comportamento termico de resinas de silicona a base de poli(N-alquilsilsesquioxanos)

Energy Technology Data Exchange (ETDEWEB)

Prado, Luis Antonio Sanchez de Almeida; Yoshida, Inez Valeria Pagotto [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica], e-mail: valeria@iqm.unicamp.br

2000-07-01

In this work, T, T{sup A}D{sup L} and T{sup A}D{sup C} silicone resins were obtained by the sol-gel process. Poly(dimethylsiloxane) and tetramethyl diethoxydisiloxane were used as sources of D{sup L} and D{sup C} units, respectively, while n-octyltriethoxysilane and n-dodecyltriethoxysilane were employed as precursors for T{sup A} units. The molecular structure and the composition were investigated by FT-IR and {sup 29}Si MAS NMR spectra. A partial loss of TMDES was observed during the curing of the resins. TGA traces indicated good thermal stability for all resins prepared. DSC curves showed the presence of a glass-transition and first-order transition for the resins containing n-octyl and n-dodecyl groups, respectively. The presence of the last transition could be attributed to the fusion of nano domains constituted by n-dodecyl groups. (author)

Mechanistic Insights into the Organopolymerization of N-Methyl N-Carboxyanhydrides Mediated by N-Heterocyclic Carbenes

KAUST Repository

Falivene, Laura

2016-10-04

We report on a DFT investigation of initiation, propagation, and termination in the organopolymerization of N-methyl N-carboxyanhydrides toward cyclic poly(N-substituted glycine)s, promoted by N-heterocyclic carbenes (NHC). Calculations support the experimentally based hypothesis of two competing initiation pathways. The first leading to formation of a zwitterionic adduct by nucleophilic addition of the NHC to one of the carbonyl groups of monomer. The second via acid–base reactivity, starting with the NHC promoted abstraction of a proton from the methylene group of the monomer, leading to an ion-pair-type adduct, followed by nucleophilic attack of the adduct to a new monomer molecule. Chain elongation can proceed from both the initiation adducts via nucleophilic attack of the carbamate chain-end to a new monomer molecule via concerted elimination of CO2 from the carbamate chain-end. Energy barriers along all the considered termination pathways are remarkably higher that the energy barrier along the chain elongation pathways, consistent with the quasi-living experimental behavior. Analysis of the competing termination pathways suggests that the cyclic species determined via MALDI-TOF MS experiments consists of a zwitterionic species deriving from nucleophilic attack of the N atom of the carbamate chain-end to the C═O group bound to the NHC moiety.

Estudio de la electrooxidación de CO en electrodos de Pt(poly) y Pt(hkl) : el origen del pre-pico

OpenAIRE

López Cudero, Ana

2011-01-01

Se han combinado técnicas electroquímicas clásicas como la voltametría cíclica, con otras como la espectroscopía infrarroja con transformada de Fourrier, la microscopia de efecto túnel o la generación de segundo armónico, a fin de estudiar a fondo las variaciones del recubrimiento en función del potencial de admisión a explicar la existencia del pre-pico en los voltamogramas de stripping de CO

Características de adhesión entre fibras de queratina y poliéster insaturado

Directory of Open Access Journals (Sweden)

Marco Paniagua

2008-01-01

Full Text Available En este trabajo se presentan los métodos y resultados utilizados para determinar las características de adhesión entre fibras de queratina y una matriz de poliéster insaturado. Las fibras fueron preparadas con varios tratamientos superficiales para determinar el efecto de estos en la adhesión a la matriz mediante: i pruebas de desgarre de monofilamento, pull-out, como método directo de medición y ii pruebas de tensión en laminados como método indirecto para estudiar, mediante microscopía electrónica SEM, la adhesión fibra matriz en la zona de fractura.

Sortase-Mediated Ligation of Purely Artificial Building Blocks

Directory of Open Access Journals (Sweden)

Xiaolin Dai

2018-02-01

Full Text Available Sortase A (SrtA from Staphylococcus aureus has been often used for ligating a protein with other natural or synthetic compounds in recent years. Here we show that SrtA-mediated ligation (SML is universally applicable for the linkage of two purely artificial building blocks. Silica nanoparticles (NPs, poly(ethylene glycol and poly(N-isopropyl acrylamide are chosen as synthetic building blocks. As a proof of concept, NP–polymer, NP–NP, and polymer–polymer structures are formed by SrtA catalysis. Therefore, the building blocks are equipped with the recognition sequence needed for SrtA reaction—the conserved peptide LPETG—and a pentaglycine motif. The successful formation of the reaction products is shown by means of transmission electron microscopy (TEM, matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-ToF MS, and dynamic light scattering (DLS. The sortase catalyzed linkage of artificial building blocks sets the stage for the development of a new approach to link synthetic structures in cases where their synthesis by established chemical methods is complicated.

DIVERSIFICACIÓN DE LA ACTIVIDAD TURÍSTICA DE BALNEARIOS: EL CASO DE PEHUÉN CO, ARGENTINA

Directory of Open Access Journals (Sweden)

María Luján Bustos

2016-01-01

Full Text Available Para desarrollar un Manejo Integral Costero de localidades turísticas es necesario identificar posibles alternativas que ayuden a diversificar su economía. La localidad de Pehuén Co (provincia de Buenos Aires, Argentina es un típico caso de turismo sin diversificación. Se realizó un análisis de su oferta y demanda turística mediante encuestas y relevamientos. Esto permitió trazar una zonificación del área de estudio según el grado de desarrollo turístico. Como resultado se identifican nuevas zonas con potencial turístico que permitiría la diversificación de la economía local y regional. Estas alternativas potenciarían un uso sustentable de los recursos y atractivos de Pehuén Co.

A clinical study of auditory hallucination by single photon emission computed tomography (SPECT) using N-isopropyl-p-[123I] iodoamphetamine (IMP)

International Nuclear Information System (INIS)

Gyobu, Tsuyoshi; Inao, Gyoshun; Ii, Masayasu; Matsuda, Hiroshi; Hisada, Kinichi.

1988-01-01

SPECT images with N-isopropyl-p-I-123 iodoamphetamine (IMP) were reviewed in 24 right-handed patients with hallucination (H Group), comprising schizophrenic disorder (20), alcohol hallucinosis (2), epileptic hallucinosis (one), and organic mental disorder (one), and 50 subjects without hallucination (non-H Group), consisting of 39 patients with mental or organic central nervous system disorder and 11 healthy volunteers. Early SPECT images showed an increased uptake of IMP in the auditory area and angular gyrus in 23 patients of H Group and 3 persons of non-H Group. A similar uptake of IMP was seen on delayed SPECT images in 12 patients of H Group and 4 patients with a history of hallucination of non-H Group. There were no SPECT findings specific to diseases. For schizophrenic patients, increased and decreased uptakes of IMP were seen in the striatolimbic region and in the bilateral frontal lobes, respectively, irrespective of hallucination. Factors contributing to increased uptake of IMP are discussed. (Namekawa, K.) 84 refs

New Poly(amide-imide)/Nanocomposites Reinforced Silicate Nanoparticles Based on N-pyromellitimido-L-phenyl Alanine Containing Ether Moieties

Science.gov (United States)

Faghihi, Khalil; Shabanian, Meisam; Dadfar, Ehsan

2012-02-01

A series of Poly(amide-imide)/montmorillonite nanocomposites containing N-pyromellitimido-L-phenyl alanine moiety in the main chain were synthesized by a convenient solution intercalation technique. Poly(amide-imide) (PAI) 5 as a source of polymer matrix was synthesized by the direct polycondensation reaction of N-pyromellitimido-L-phenyl alanine 3 with 4,4'-diamino diphenyl ether 4 in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). The resulting nanocomposite films were characterized by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The results showed that organo-modified clay was dispersed homogeneously in PAI matrix. TGA indicated an enhancement of thermal stability of new nanocomposites compared with the pure polymer.

Clay-enhanced DNA separation in low-molecular-weight poly(N,N-dimethylacrylamide) solution by capillary electrophoresis.

Science.gov (United States)

Liang, D; Song, L; Chen, Z; Chu, B

2001-06-01

The effect of the separation medium in capillary electrophoresis consisting of a low-molecular-mass poly(N,N-dimethylacrylamide) (PDMA) solution on the DNA separation by adding a small amount of montmorillonite clay into the polymer matrix is presented. On the separation of the pBR322/HaeIII digest, both the resolution and the efficiency were increased by adding 2.5-5.0 x 10(-5) g/mL clay into the 5% w/v PDMA with a molecular mass of only 100 K. Moreover, there was no increase in the migration time of DNA fragments. Similar results were observed by using a C-terminated pGEM-3Zf(+) sequencing DNA sample in a sequencing buffer. Experimental data also showed that the addition of clay increased the viscosity of the polymer solution. We attribute this effect to the structural change of the polymer matrix caused by the exfoliated clay sheets, whereby the thin clay sheets function like a "dynamic cross-linking plate" for the PDMA chains and effectively increase the apparent molecular mass of PDMA.

Co-N-macrocyclic modified graphene with excellent electrocatalytic activity for lithium-thionyl chloride batteries

International Nuclear Information System (INIS)

Li, Bimei; Yuan, Zhongzhi; Xu, Ying; Liu, Jincheng

2016-01-01

Highlights: • A Co-N-graphene catalyst composed of CoN 4 -macrocyclic-like (CoN x ) structure is synthesized. • Co-N x -Graphene has effective electrocatalytic activity for Li/SOCl 2 batteries. • The storage stability of the catalyst is attributed to its insolubility in electrolyte. - Abstract: A mixture of cobalt phthalocyanine (CoPc) and graphene is thermally decomposed at 800 °C to synthesize a novel catalyst. Scanning electron microscopy (SEM) and transmission electron microscope (TEM) show that the catalyst retains the lamellar structure of graphene. X-ray diffraction (XRD) reveals that the catalyst is no longer composed of CoPc and high-resolution TEM (HRTEM), X-ray photoelectron spectra (XPS) prove that Co and N elements have entered the graphene molecular structure, thus forming a Co-N x -graphene (Co-N x -G) catalyst composed of a CoN 4 -macrocyclic-like structure. This catalyst serves as an excellent catalyst of thionyl chloride (SOCl 2 ) reduction. Cyclic voltammetry and battery discharge tests reveal that Co-N x -G-800 substantially increases the discharge voltage and capacity of a Li/SOCl 2 battery. Moreover, Co-N x -G-800 exhibits stable catalytic activity during battery storage. Ultraviolet–visible spectroscopy shows that CoPc is soluble in a SOCl 2 electrolyte solution, whereas Co-N x -G-800 is not, this characteristic contributes to the stable catalytic property of Co-N x -G.

The distribution of N-isopropyl-p-iodoamphetamine in experimental ischemic brain of the mongolian gerbil

International Nuclear Information System (INIS)

Jinnouchi, Seishi; Hoshi, Hiroaki; Watanabe, Katsushi; Ueda, Takashi; Yamaguchi, Tadatoshi

1988-01-01

We studied the distribution of N-isopropyl-p-[I-131]-iodoamphetamine (IMP) in permanent and temporary ischemic brains of mongolian gerbils. For the permanent ischemic brain model, the right common carotid artery was ligated under ether anesthesia. For the temporary ischemic brain model, the right common carotid artery was clamped by a clip and recirculated at 3 hours thereafter. After given time intervals, 1.35 MBq (50 μCi) of IMP was injected intravenously into 17 gerbils (permanent ischemic brain model), 18 gerbils (temporary ischemic brain model) which had severe neurological symptoms, and 3 normal gerbils for controls. One minute, 10 minutes, 1 hour and 6 hours after the injection, gerbils were sacrified and autoradiography of the brain was performed. The activity of IMP in various parts of the brain was calculated from each autoradiogram. In permanent ischemic brains, low perfusion areas were observed in the right cerebral hemisphere, the brain stem (5 ∼ 20 % of normal value), and in the left hemisphere (40 ∼ 60 % of normal value). In temporary ischemic brains, focal areas of increased activity were observed in the right cerebral hemisphere and the thalamus from 10 minutes to 24 hours after recirculation. The high activity disappeared rapidly at 10 minutes after the injection. It seemed that this high activity represented luxury perfusion in the region with severe tissue damage. In the left hemisphere, almost complete recovery of perfusion occurred at 1 ∼ 3 days after recirculation. These results suggested the possibility of IMP to demonstrate cerebral ischemia, luxury perfusion and diaschisis. (author)

Crystal structure of a looped-chain CoII coordination polymer: catena-poly[[bis-(nitrato-κO)cobalt(II)]bis-[μ-bis-(pyridin-3-ylmeth-yl)sulfane-κ2N:N'

Science.gov (United States)

Moon, Suk-Hee; Seo, Joobeom; Park, Ki-Min

2017-11-01

The asymmetric unit of the title compound, [Co(NO 3 ) 2 (C 12 H 12 N 2 S) 2 ] n , contains a bis-(pyridin-3-ylmeth-yl)sulfane ( L ) ligand, an NO 3 - anion and half a Co II cation, which lies on an inversion centre. The Co II cation is six-coordinated, being bound to four pyridine N atoms from four symmetry-related L ligands. The remaining coordination sites are occupied by two O atoms from two symmetry-related nitrate anions in a monodentate manner. Thus, the Co II centre adopts a distorted octa-hedral geometry. Two symmetry-related L ligands are connected by two symmetry-related Co II cations, forming a 20-membered cyclic dimer, in which the Co II atoms are separated by 10.2922 (7) Å. The cyclic dimers are connected to each other by sharing Co II atoms, giving rise to the formation of an infinite looped chain propagating along the [101] direction. Inter-molecular C-H⋯π (H⋯ring centroid = 2.89 Å) inter-actions between one pair of corresponding L ligands and C-H⋯O hydrogen bonds between the L ligands and the nitrate anions occur in the looped chain. In the crystal, adjacent looped chains are connected by inter-molecular π-π stacking inter-actions [centroid-to-centroid distance = 3.8859 (14) Å] and C-H⋯π hydrogen bonds (H⋯ring centroid = 2.65 Å), leading to the formation of layers parallel to (101). These layers are further connected through C-H⋯O hydrogen bonds between the layers, resulting in the formation of a three-dimensional supra-molecular architecture.

Physicochemical properties of poly(lactic acid-co-glycolic acid film modified via blending with poly(butyl acrylate-co-methyl methacrylate

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Guoquan Zhu

2013-01-01

Full Text Available A series of poly(lactic acid-co-glycolic acid (PLGA/poly(butyl acrylate-co-methyl methacrylate (P(BA-co-MMA blend films with different P(BA-co-MMA mole contents were prepared by casting the polymer blend solution in chloroform. Surface morphologies of the PLGAP(BA-co-MMA blend films were studied by scanning electron microscopy (SEM. Thermal, mechanical, and chemical properties of PLGAP(BA-co-MMA blend films were investigated by differential scanning calorimeter (DSC, thermogravimetric analysis (TGA, tensile tests, and surface contact angle tests. The introduction of P(BA-co-MMA could modify the properties of PLGA films.

Ligand electronic parameters as a measure of the polarization of the C≡O bond in [M(CO)(x)L(y)]n complexes and of the relative stabilization of [M(CO)(x)L(y)](n/n+1) species.

Science.gov (United States)

Zobi, Fabio

2010-11-15

The electronic description of octahedral (fac-[M(CO)(3)L(3)](n), with M = Re, Ru, and Mn, and [Cr(CO)(5)L](n)), square-planar (cis-[Pt(CO)(2)L(2)](n)), and tetrahedral ([Ni(CO)(3)L](n)) carbonyl complexes (where L = monodentate ligand) was obtained via density functional theory and natural population analyses in order to understand what effects are probed in these species by vibrational spectroscopy and electrochemistry as a function of the ligand electronic parameter of the associated L. The analysis indicates that while ligand electronic parameters may be considered as a measure of the net donor power of the ligand, the net transfer of the electron density (or charge) does not occur from the ligand to the metal ion. In [M(CO)(x)L(y)](n) carbonyl species, the charge transfer occurs from the ligand L to the oxygen atom of the bound carbon monoxides. This charge transfer translates into changes of the polarization (or permanent dipole) and the covalency of the C≡O bonds, and it is this effect that is probed in IR spectroscopy. As the analysis shifts from IR radiations to electrochemical potentials, the parameters best describe the relative thermodynamic stability of the oxidized and reduced [M(CO)(x)L(y)](n/n+1) species. No relationship is found between the metal natural charge of the [M(CO)(x)L(y)](n) fragments analyzed and the parameters. Brief considerations are given on the possible design of CO-releasing molecules.

Entre la literatura y la práctica política. Una aproximación a la Venezuela de Rómulo Gallegos

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Lisandro Angelini

2014-01-01

Full Text Available La trayectoria de Rómulo Gallegos, reflejada en sus obras literarias, así como en su rol intelectual y político, resulta una opción pertinente para el análisis del pensamiento de este autor durante el período de consolidación del modelo de Estado-Nación venezolano moderno. Así, el objetivo general de este trabajo es determinar la interacción entre la producción literaria de Rómulo Gallegos y el pro- ceso de construcción del Estado-Nación, teniendo como referencia las condiciones sociales, culturales y políticas del espacio venezolano y el contexto latinoamericano del siglo XX. En tanto que como objetivos específicos se persigue, en primer lugar, identificar el rol intelectual de Gallegos y princi- palmente el impacto de su obra durante la primera mitad del siglo XX. En segundo lugar, analizar las preocupaciones políticas del autor, y el modo en que estas condicionan y contribuyen al contenido de sus narraciones literarias. Respecto al abordaje metodológico de la investigación, este se ha planteado en términos cuali- tativos, debido al carácter del problema y los objetivos definidos. Se ha realizado paralelamente una lectura profunda de las fuentes obtenidas, así como de la bibliografía en general, procediendo a su recolección y organización de las mismas siguiendo la lógica de los objetivos propuestos. Los resultados a los que nos ha conducido el relevamiento de las fuentes y la bibliografía, po- nen de manifiesto que el intento de reconfigurar el relato fundacional venezolano desde la ficción literaria, por un lado, y el objetivo de consolidar un proyecto político renovador, por otro, si bien gozaron de una amplia difusión editorial, no pudieron verse materializados desde la práctica polí- tica, ya que un golpe de Estado, que alejó a Gallegos tempranamente del poder ejecutivo, reinstauró en Venezuela una visión republicana tradicional y un gobierno elitista y autoritario.

Inversion of exchange bias and complex magnetization reversal in full-nitride epitaxial γ′-Fe{sub 4}N/CoN bilayers

Energy Technology Data Exchange (ETDEWEB)

Li, Z.R. [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, Institute of Advanced Materials Physics, Faculty of Science, Tianjin University, Tianjin 300072 (China); Mi, W.B., E-mail: miwenbo@tju.edu.cn [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, Institute of Advanced Materials Physics, Faculty of Science, Tianjin University, Tianjin 300072 (China); Wang, X.C. [Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Electronics Information Engineering, Tianjin University of Technology, Tianjin 300384, China (China); Bai, H.L. [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology, Institute of Advanced Materials Physics, Faculty of Science, Tianjin University, Tianjin 300072 (China)

2015-04-01

Exchange bias has been observed in the full-nitride epitaxial γ′-Fe{sub 4}N/CoN bilayers. With the increase of temperature, the sign of exchange bias (EB) is inverse, which is independent on the cooling field and training effect. This novel behavior appears in the bilayers with different CoN and γ′-Fe{sub 4}N thicknesses. The inversion of EB sign not only occurs at low temperatures, but also takes place even at 200 K for the 10 and 12 nm thick CoN layer. With the decreased γ′-Fe{sub 4}N layer thickness, the inversion temperature of EB sign shows a roughly increased tendency. For the bilayer with a 4 nm-thick γ′-Fe{sub 4}N, the interfacial magnetization reversal presents a complex trend, which is considered as the combined actions of the disordered ferromagnetic spins and various competed magnetic structures. This new manifestation of EB has been discussed in terms of the complicated interfacial spin structures and frustration effects due to the competition between the ferromagnetic and antiferromagnetic exchange interactions at the interface. - Highlights: • Exchange bias (EB) sign reverses from negative to positive with increasing temperature in epitaxial γ′-Fe{sub 4}N/CoN bilayers. • The positive EB can be attributed to the antiferromagnetic interfacial coupling and frustrated interfacial spin structures. • The EB transition temperature is not monotonically dependent on CoN thickness t{sub CoN}. • For a 4-nm γ′-Fe{sub 4}N, the unusual hysteresis loops are observed.

Effect of Compatibilization on Poly-ε-Caprolactone Grafting onto Poly(ethylene-co-vinyl alcohol

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Mohamed Taha

2011-10-01

Full Text Available The non-miscibility of the reactants during solvent free poly-ε-caprolactone grafting onto poly(ethylene-co-vinyl alcohol (EVOH dramatically affects reaction kinetics. Different solutions were proposed to accelerate the exchange reactions between poly(ethylene-co-vinyl alcohol and poly-ε-caprolactone. Reactions were conducted in a batch reactor or a mini twin-screw extruder. The addition of a poly(ethylene-co-vinyl alcohol-g-poly-ε-caprolactone copolymer increased the compatibility of the reactants and led to a higher reaction rate. This copolymer was either prepared separately and added at the reaction beginning or prepared in situ grafting caprolactone from EVOH. The reactive system evolution was analyzed using molar mass evolution, microstructure characterization, thermal properties and the reactive blend morphology. The compatibilization effect combined with optimized reaction conditions, such as concentration and nature of catalyst and temperature, resulted in an important increase in reaction rates. Among the tested catalysts, 1,5,7-Triazabicyclo [4.4.0]dec-5-ene was a more efficient catalyst for grafting reactions than Tin (II 2-ethylhexanoate.

Gasificación con CO2 de carbonizados de aserrín de Pinus caribaea Morelet var. cariba

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F. Márquez-Montesino

2004-01-01

Full Text Available Dada la importancia del estudio de la reactividad de los carbones con el fin de estudiar su activación, se desarrolló la gasificación con CO2 de un carbón obtenido de aserrín de Pinus caribaea. Los ensayos termogravimétricos se realizaron en un sistema modular de CI Electronics, las temperaturas de gasificación escogidas fueron 750, 775, 800 y 825 °C. Para calcular los valores de reactividad normalizada, se determinó el área de superficie por adsorción de CO2 a 273 K, en un equipo Autosorb-1 de Quantachrome Corporation sobre muestras desgasificadas a 180 °C y un vacío igual o mayor de 50 mtorr durante 8 h. De la gasificación con CO2 se representó gráficamente la reactividad frente a valores de conversión del carbonizado, indicando un aumento de la reactividad con el aumento de la temperatura de gasificación, lo que se explica por el desarrollo del área de superficie con el avance de la reacción y el efecto catalítico del mineral al aumentar su concentración en el sustrato. La representación gráfica de la ecuación de Arrhenius para la reactividad, indica que en las condiciones estudiadas en termobalanza, el proceso de gasificación ocurre bajo control de la etapa química, donde el valor de la energía de activación aparente es de ± 234 kJ/mol.

Regional cerebral blood flow measurement using N-isopropyl-p-(/sup 123/I) iodoamphetamine and rotating gamma camera emission computed tomography

Energy Technology Data Exchange (ETDEWEB)

Matsuda, Hiroshi; Seki, Hiroyasu; Ishida, Hiroko (Kanazawa Univ. (Japan). School of Medicine)

1985-01-01

Thirty-one regional cerebral blood flow (rCBF) measurements were performed on 26 patients with cerebrovascular accidents using N-Isopropyl-p-(/sup 123/I) Iodoamphetamine (/sup 123/I-IMP) and rotating gamma camera emission computed tomography (ECT). The equation for determining rCBF is as follows: F=100.R.Cb/(N.A), where F is rCBF in ml/100 g/min., R is the constant withdrawal rate of arterial blood in ml/min., Cb is the brain activity concentration in ..mu..Ci/g, A is the total activity (5 min.) in the withdrawal arterial whole blood in ..mu..Ci and N is the fraction of A that is true tracer activity (0.75). In determining Cb at 5 min. after injection, reconstructed counts from 35 min. to 59 min. were corrected to represent those from 4 min. to 5 min. with the use of time activity curve for the entire brain immediately after injection to 30 min. Reconstructed counts of central region in tomographic image were corrected 118% of the obtained values from the result of the counting rate ratio between peripheral and central regions of interest obtained from phantom study. Brain mean blood flow values were distributed from 11 to 39 ml/100 g/min. In 119 cortical regions obtained from 11 measurements in 9 patients, there was a significant correlation (r=0.41, p < 0.001) between rCBF values obtained from /sup 123/I-IMP and rotating gamma camera ECT and those from /sup 133/Xe inhalation method. rCBF measurement using /sup 123/I-IMP and rotating gamma camera ECT is not only relatively noninvasive measurement for the entire brain but also three-dimensional evaluation. Besides, it is superior in spatial resolution and accuracy to conventional /sup 133/Xe clearance method.

Initiated chemical vapor deposition of thermoresponsive poly(N-vinylcaprolactam) thin films for cell sheet engineering.

Science.gov (United States)

Lee, Bora; Jiao, Alex; Yu, Seungjung; You, Jae Bem; Kim, Deok-Ho; Im, Sung Gap

2013-08-01

Poly(N-vinylcaprolactam) (PNVCL) is a thermoresponsive polymer known to be nontoxic, water soluble and biocompatible. Here, PNVCL homopolymer was successfully synthesized for the first time by use of a one-step vapor-phase process, termed initiated chemical vapor deposition (iCVD). Fourier transform infrared spectroscopy results showed that radical polymerization took place from N-vinylcaprolactam monomers without damaging the functional caprolactam ring. A sharp lower critical solution temperature transition was observed at 31°C from the iCVD poly(N-vinylcaprolactam) (PNVCL) film. The thermoresponsive PNVCL surface exhibited a hydrophilic/hydrophobic alteration with external temperature change, which enabled the thermally modulated attachment and detachment of cells. The conformal coverage of PNVCL film on various substrates with complex topography, including fabrics and nanopatterns, was successfully demonstrated, which can further be utilized to fabricate cell sheets with aligned cell morphology. The advantage of this system is that cells cultured on such thermoresponsive surfaces could be recovered as an intact cell sheet by simply lowering the temperature, eliminating the need for conventional enzymatic treatments. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Hacia la gestión ambiental de residuos sólidos en las metrópolis de América Latina

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Luz Ángela Rodríguez Escobar

2002-11-01

Full Text Available La contaminación generada por la acumulación de residuos sólidos está presente en todas las metrópolis de América Latina, afectando el ecosistema. Dicha contaminación es causada por la población y su aglomeración en zonas urbanas. Los datos estadísticos de las metrópolis latinoamericanas permiten establecer una relación directa entre población y acumulación de residuos sólidos y también entre nivel de ingresos y generación de residuos, mostrando que la relación población-residuos sólidos está mediada por variables económicas y culturales. La información de generación de basura por persona y su respectivo nivel socioeconómico permite establecer diferencias de cantidad y calidad de los residuos generados por individuos de distinto nivel socioeconómico, que a su vez se asocian a diferentes estilos de vida y patrones de consumo. Así, la producción de basura es potenciada por la dinámica de producción y consumo y por la dinámica demográfica, siendo un efecto no esperado de ambas, que convierte los residuos sólidos en un subproducto del modelo de desarrollo y la dinámica demográfica. En el escenario planteado, el problema ambiental de los residuos sólidos en .las metrópolis de América Latina aparece como irresoluto y la decisión de resolverlo de manera fundamental pasa por cambiar el modelo de desarrollo y el comportamiento de la sociedad. Una solución menos extrema consiste en hacer un manejo integral de los residuos sólidos a través de políticas de gestión integral.

N-isopropyl-[123I]p-iodoamphetamine: single-pass brain uptake and washout; binding to brain synaptosomes; and localization in dog and monkey brain

International Nuclear Information System (INIS)

Winchell, H.S.; Horst, W.D.; Braun, L.; Oldendorf, W.H.; Hattner, R.; Parker, H.

1980-01-01

The kinetics of N-isopropyl-p-[ 123 I]iodoamphetamine in rat brains were determined by serial measurements of brain uptake index (BUI) after intracarotid injection; also studied were its effects on amine uptake and release in rat's brain cortical synaptosomes; and its in vivo distribution in the dog and monkey. No specific localization in brain nuclei of the dog was seen, but there was progressive accumulation in the eyes. Rapid initial brain uptake in the ketamine-sedated monkey was noted, and further slow brain uptake occurred during the next 20 min but without retinal localization. High levels of brain activity were maintained for several hours. The quantitative initial single-pass clearance of the agent in the brain suggests its use in evaluation of regional brain perfusion. Its interaction with brain amine-binding sites suggests its possible application in studies of cerebral amine metabolism

Energetics and magnetism of Co-doped GaN(0001) surfaces: A first-principles study

International Nuclear Information System (INIS)

Qin, Zhenzhen; Xiong, Zhihua; Chen, Lanli; Qin, Guangzhao

2014-01-01

A comprehensive first-principles study of the energetics, electronic, and magnetic properties of Co-doped GaN(0001) thin films are presented and the effect of surface structure on the magnetic coupling between Co atoms is demonstrated. It is found that Co atoms prefer to substitute the surface Ga sites in different growth conditions. In particular, a CoN/GaN interface structure with Co atoms replacing the first Ga layer is preferred under N-rich and moderately Ga-rich conditions, while CoGa x /GaN interface is found to be energetically stable under extremely Ga-rich conditions. It is worth noted that the antiferromagnetic coupling between Co atoms is favorable in clean GaN(0001) surface, but the existence of ferromagnetism would be expected to occur as Co concentration increased in Ga-bilayer GaN(0001) surface. Our study provides the theoretical understanding for experimental research on Co-doped GaN films and might promise the Co:GaN system potential applications in spin injection devices

Single photon emission computed tomography (SPECT) findings using N-isopropyl-p-[{sup 123}I]iodoamphetamine ({sup 123}I-IMP) in schizophrenia and atypical psychosis

Energy Technology Data Exchange (ETDEWEB)

Suga, Hidemichi; Hayashi, Takuji; Mitsugi, Ohara [Aichi Medical Univ., Nagakute (Japan)

1994-12-01

As a basis for possible classification of schinzophrenic psychoses into schizophrenia and atypical psychosis, we studied the brain functional differences among 16 schizophrenic patients, 16 atypical psychosis patients and 16 healthy volunteers by single photon emission computed tomography (SPECT) using N-isopropyl-p-[{sup 123}I] iodoamphetamine. As a result, schizophrenics showed hypofrontality. On the other hand, atypical psychotics had no such hypofrontality but showed a reduced uptake rate in the right thalamic region. No influence of sex, duration of illness and medication was confirmed by the findings. The results suggest that schizophrenics might have some lesions in the frontal regions, whereas atypical psychotics might have no such lesions, but dysfunction in the right thalamic region. Consequently, the SPECT findings as least indicate possibly different etiologies for schizophrenia and atypical psychosis. (author).

Arqueología en Egipto y Sudán. El proyecto de investigación de Ehnasya el Medina (Heracleópolis Magna, Egipto

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Pérez Die, María del Carmen

1998-12-01

Full Text Available Not available.La presencia española en excavaciones en Egipto y Sudán es relativamente reciente. Se inició en la década de los años sesenta mediante la participación en la campaña de salvamento de Nubia y ha continuado hasta la actualidad, gracias a una serie de proyectos de investigación arqueológica como el que se desarrolla en el yacimiento de Ehnasya el Medina (Heracleópolis Magna, que está proporcionando conclusiones fundamentales para la historia de Egipto. Existen, también, otros proyectos que muestran el interés por la egiptología, así como el alto desarrollo que esta ciencia ha alcanzado en nuestro país.

APLICACIÓN DE LA METODOLOGÍA DE SUPERFICIE DE RESPUESTA EN UN PROCESO DE ABSORCIÓN DEL CO2 DE UN BIOGÁS EN UNA SOLUCIÓN ALCALINA

Directory of Open Access Journals (Sweden)

JULIÁN DAVID MUÑOZ SIERRA

2009-01-01

Full Text Available Se empleó un diseño factorial 23 ampliado a central compuesto para investigar los efectos de las variables relación [CO3=/HCO3], presión inicial del gas y temperatura del sistema gas-líquido, en el proceso de absorción de CO2 en una solución alcalina de carbonato-bicarbonato de sodio, utilizando un biogás simulado como mezcla gaseosa problema. Se encontró una significante influencia de la relación de concentración en el proceso de remoción del dióxido de carbono, obteniéndose un modelo de superficie de respuesta de segundo orden validado estadísticamente mediante análisis de varianza, el cual explica cerca del 98.41% de la variabilidad del cambio del porcentaje (v/v de CO2 en el biogás simulado. Se logró una máxima remoción de CO2 del 62.86% para un tiempo de contacto de sesenta minutos.

3B11-N, a monoclonal antibody against MERS-CoV, reduces lung pathology in rhesus monkeys following intratracheal inoculation of MERS-CoV Jordan-n3/2012

International Nuclear Information System (INIS)

Johnson, Reed F.; Bagci, Ulas; Keith, Lauren; Tang, Xianchun; Mollura, Daniel J.; Zeitlin, Larry; Qin, Jing; Huzella, Louis; Bartos, Christopher J.; Bohorova, Natasha; Bohorov, Ognian; Goodman, Charles; Kim, Do H.; Paulty, Michael H.; Velasco, Jesus; Whaley, Kevin J.; Johnson, Joshua C.; Pettitt, James; Ork, Britini L.; Solomon, Jeffrey

2016-01-01

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) was identified in 2012 as the causative agent of a severe, lethal respiratory disease occurring across several countries in the Middle East. To date there have been over 1600 laboratory confirmed cases of MERS-CoV in 26 countries with a case fatality rate of 36%. Given the endemic region, it is possible that MERS-CoV could spread during the annual Hajj pilgrimage, necessitating countermeasure development. In this report, we describe the clinical and radiographic changes of rhesus monkeys following infection with 5×10"6 PFU MERS-CoV Jordan-n3/2012. Two groups of NHPs were treated with either a human anti-MERS monoclonal antibody 3B11-N or E410-N, an anti-HIV antibody. MERS-CoV Jordan-n3/2012 infection resulted in quantifiable changes by computed tomography, but limited other clinical signs of disease. 3B11-N treated subjects developed significantly reduced lung pathology when compared to infected, untreated subjects, indicating that this antibody may be a suitable MERS-CoV treatment. - Highlights: • MERS-CoV Jordan-n3/2012 challenge of rhesus monkeys results in a mild disease. • CT can be used to monitor disease progression to aid models of human disease. • Treatment with the human monoclonal antibody 3B11-N resulted in decreased disease.

3B11-N, a monoclonal antibody against MERS-CoV, reduces lung pathology in rhesus monkeys following intratracheal inoculation of MERS-CoV Jordan-n3/2012

Energy Technology Data Exchange (ETDEWEB)

Johnson, Reed F., E-mail: johnsonreed@mail.nih.gov [Emerging Viral Pathogens Section National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702 (United States); Bagci, Ulas [Center for Infectious Disease Imaging, National Institutes of Health Clinical Center, Bethesda MD 20892 (United States); Center for Research in Computer Vision (CRCV), Department of Electrics Electronics and Computer Science, University of Central Florida, Orlando, FL 32816, USA. (United States); Keith, Lauren [Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702 (United States); Tang, Xianchun [Department of Cancer Immunology & AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215 (United States); Mollura, Daniel J. [Center for Infectious Disease Imaging, National Institutes of Health Clinical Center, Bethesda MD 20892 (United States); Zeitlin, Larry [Mapp Biopharmaceutical, Inc., San Diego CA 92121 (United States); Qin, Jing [Biostatistics Research Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 (United States); Huzella, Louis; Bartos, Christopher J. [Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702 (United States); Bohorova, Natasha; Bohorov, Ognian; Goodman, Charles; Kim, Do H.; Paulty, Michael H.; Velasco, Jesus; Whaley, Kevin J. [Mapp Biopharmaceutical, Inc., San Diego CA 92121 (United States); Johnson, Joshua C.; Pettitt, James; Ork, Britini L. [Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, MD 21702 (United States); Solomon, Jeffrey [Clinical Research Directorate/Clinical Monitoring Research Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research,Frederick, MD 21702-USA. (United States); and others

2016-03-15

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) was identified in 2012 as the causative agent of a severe, lethal respiratory disease occurring across several countries in the Middle East. To date there have been over 1600 laboratory confirmed cases of MERS-CoV in 26 countries with a case fatality rate of 36%. Given the endemic region, it is possible that MERS-CoV could spread during the annual Hajj pilgrimage, necessitating countermeasure development. In this report, we describe the clinical and radiographic changes of rhesus monkeys following infection with 5×10{sup 6} PFU MERS-CoV Jordan-n3/2012. Two groups of NHPs were treated with either a human anti-MERS monoclonal antibody 3B11-N or E410-N, an anti-HIV antibody. MERS-CoV Jordan-n3/2012 infection resulted in quantifiable changes by computed tomography, but limited other clinical signs of disease. 3B11-N treated subjects developed significantly reduced lung pathology when compared to infected, untreated subjects, indicating that this antibody may be a suitable MERS-CoV treatment. - Highlights: • MERS-CoV Jordan-n3/2012 challenge of rhesus monkeys results in a mild disease. • CT can be used to monitor disease progression to aid models of human disease. • Treatment with the human monoclonal antibody 3B11-N resulted in decreased disease.

Poly(Ethylene Oxide)-block-Polysulfone-block-Poly(Ethylene Oxide) / Poly(etherblock-amide) Composite Membrane for Carbon Dioxide Separation

KAUST Repository

Omoniyi, Adekunle

2012-07-01

This research study describes the gas separation performance of different sets of Polyethyleneoxide-block-Polysulfone-block-Polyethyleneoxide/poly(ether-block-amide) (PEO-b-PSU-b-PEO/Pebax) composite membranes for CO2 separation from N2 and CH4. Gas permeation properties of the membranes prepared were studied at ambient temperature (21oC) and 8bar. The dependence of gas flux and selectivity on pressure was explored for different pressures from 2.5 bar up to 19 bar also at ambient temperature. Pebax/PAN composite membranes have a range of CO2 permeance of 4467±274 GPU, 365±64 GPU for CH4 and 152±17 GPU for N2 with CO2/N2 and CO2/CH4selectivities ranges of 30 and 13 respectively. Improved CO2/N2 and CO2/CH4 selectivities coupled with flux reduction were obtained from the introduction of PEO-b-PSU-b-PEO films on Pebax/PAN composite membranes. The gas flux reduced to about one-tenth of Pebax/PAN membrane’s while the selectivities obtained for all the PEO-b-PSU-b- PEO/Pebax/PAN membrane range from 33 to 60 for CO2/N2 and 17 to 33 for CO2/CH4 as the thickness of PEO-b-PSU-b-PEO top layer increases.

New optically active and thermally stable poly(amide-imide)s containing N,N'-(Bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic)-bis-L-alanine and aromatic diamines: synthesis and characterization

International Nuclear Information System (INIS)

Faghihi, Khalil; Absalar, Morteza; Hajibeygi, Mohsen

2009-01-01

Five new optically active poly(amide-imide)s (PAIs) 6a-e were prepared by direct polycondensation reaction of the newly synthesized N,N'-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetra carboxylic)-bis-L-alanine 4 with various aromatic diamines 5a-e using polar aprotic solvents such as N-methyl-2-pyrrolidone (NMP). In this technique triphenyl phosphite (TPP) and pyridine were used as condensing agents to form poly(amide-imide)s through the N-phosphonium salts of pyridine. All of the polymers were obtained in quantitative yields with inherent viscosities between 0.29-0.46 dL g -1 and were highly soluble in polar aprotic solvents such as N,N-dimethyl acetamide (DMAc), N,N-dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), N-methyl- 2-pyrrolidone (NMP) and solvents such as sulfuric acid. They were fully characterized by means of 1 H NMR, FTIR spectroscopy, elemental analyses, inherent viscosity, solubility test, specific rotation and thermal properties of these polymers were investigated using thermogravimetric analysis techniques (TGA and DTG). (author)

Development of CO2 Selective Poly(Ethylene Oxide-Based Membranes: From Laboratory to Pilot Plant Scale

Directory of Open Access Journals (Sweden)

Torsten Brinkmann

2017-08-01

Full Text Available Membrane gas separation is one of the most promising technologies for the separation of carbon dioxide (CO2 from various gas streams. One application of this technology is the treatment of flue gases from combustion processes for the purpose of carbon capture and storage. For this application, poly(ethylene oxide-containing block copolymers such as Pebax® or PolyActive™ polymer are well suited. The thin-film composite membrane that is considered in this overview employs PolyActive™ polymer as a selective layer material. The membrane shows excellent CO2 permeances of up to 4 m3(STP·(m2·h·bar−1 (1 bar = 105 Pa at a carbon dioxide/nitrogen (CO2/N2 selectivity exceeding 55 at ambient temperature. The membrane can be manufactured reproducibly on a pilot scale and mounted into flat-sheet membrane modules of different designs. The operating performance of these modules can be accurately predicted by specifically developed simulation tools, which employ single-gas permeation data as the only experimental input. The performance of membranes and modules was investigated in different pilot plant studies, in which flue gas and biogas were used as the feed gas streams. The investigated processes showed a stable separation performance, indicating the applicability of PolyActive™ polymer as a membrane material for industrial-scale gas processing.

A new graphic method for evaluation of distribution volume on N-isopropyl-p-[[sup 123]I]iodoamphetamine (IMP) SPECT

Energy Technology Data Exchange (ETDEWEB)

Odano, Ikuo; Takahashi, Naoya; Ohtaki, Hiroh; Noguchi, Eikichi; Hatano, Masayoshi; Yamasaki, Yoshihiro; Nishihara, Mamiko (Niigata Univ. (Japan). School of Medicine); Ohkubo, Masaki; Yokoi, Takashi

1993-10-01

We developed a new graphic method using N-isopropyl-p-[[sup 123]I]iodoamphetamine (IMP) and SPECT of the brain, the graph on which all three parameters, cerebral blood flow, distribution volume (V[sub d]) and delayed count to early count ratio (Delayed/Early ratio), were able to be evaluated simultaneously. The kinetics of [sup 123]I-IMP in the brain was analyzed by a 2-compartment model, and a standard input function was prepared by averaging the time activity curves of [sup 123]I-IMP in arterial blood on 6 patients with small cerebral infarction etc. including 2 normal controls. Being applied this method to the differential diagnosis between Parkinson's disease and progressive supranuclear palsy, we were able to differentiate both with a glance, because the distribution volume of the frontal lobe significantly decreased in Parkinson's disease (Mean[+-]SD; 26[+-]6 ml/g). This method was clinically useful. We think that the distribution volume of [sup 123]I-IMP may reflect its retention mechanism in the brain, and the values are related to amine, especially to dopamine receptors and its metabolism. (author).

Effect of the different chain transfer agents on molecular weight and optical properties of poly(methyl methacrylate)

Science.gov (United States)

Çetinkaya, Onur; Demirci, Gökhan; Mergo, Paweł

2017-08-01

Investigation of molecular weight and optical properties of poly(methyl metacrylate) (PMMA) polymerized in house with different chain transfer agents was studied. Isopropyl alcohol (IPA), n-butyl mercaptan (nBMC) and pentamethyl disilane (PMDS) were used as chain transfer agents. The molecular weight (Mw) of PMMA samples were measured by Ostwald viscometer. Mw of bulk polymer samples were decreased with increase the concentration of chain transfer agents (CTA). Since reactivity of used CTAs is not same, molecular weights of samples which were produced with different type of CTA but same concentration of CTA was varied. Higher concentration of n-BMC showed higher scattering. Transmission of samples could not be correlated with different concentration of CTA. Refractive index of samples was not affected by concentration of CTA nevertheless higher molecular weight of CTA showed higher refractive index.

Study on the performance of eosin-doped poly(vinyl alcohol)/acrylamide photopolymer films for holographic recording using 488-nm wavelength

Science.gov (United States)

Rajesh, Chelakkal Sukumaran; Sreeroop, Sasidharan Savithrydevi; Pramitha, Vayalamkuzhi; Joseph, Rani; Sreekumar, Krishnapillai; Kartha, Cheranellore Sudha

2011-12-01

This article reports a study done on eosin-doped poly(vinyl alcohol)/acrylamide films for holographic recording using 488 nm Ar+ laser. Films were fabricated using gravity settling method at room temperature and were stored under normal laboratory conditions. Ar+ laser (488 nm) was used for fringe recording. Characterization was done by real time transmittance measurement, optical absorption studies, and diffraction efficiency measurements. Various holographic parameters such as exposure energy, recording power, spatial frequency, etc., were optimized so as to ensure maximum performance. More than 85% diffraction efficiency was obtained at an exposure energy of 50 mJ/cm2 in the optimized film. Efforts were taken to study the environmental stability of this self-developing polymeric material by looking at its shelf life and storage life. Compatibility for recording transmission hologram was also checked.

Biomolecular Chemistry of Isopropyl Fibrates

Science.gov (United States)

Rath, Niharika; Kotheimer, Amenda; Miller, Chad; Zeller, Matthias; Rath, Nigam P.

2012-01-01

Isopropyl 2-[4-(4-chlorobenzoyl)-phenoxy]-2-methylpropanoic acid and isopropyl 2-(4-chlorophenoxy)-2-methylpropanoate, also known as fenofibrate and isopropyl clofibrate, are hypolipidemic agents of the fibrate family. In a previously reported triclinic structure of fenofibrate (polymorph I) the methyl groups of the isopropyl moiety (iPr) are located symmetrically about the carboxylate group. We report a new monoclinic form (polymorph II) of fenofibrate and a first structural description of isopropyl clofibrate, and in these the methyl groups are placed asymmetrically about the carboxylate group. In particular the dihedral (torsion) angle between the hydrogen atom on the secondary C and the C atom of the carboxyl group makes a 2.74° angle about the ester O-C bond in the symmetric fenofibrate structure of polymorph I, whereas the same dihedral angle is 45.94° in polymorph II and -30.9° in the crystal structure of isopropyl clofibrate. Gas phase DFT geometry minimizations of fenofibrate and isopropyl clofibrate result in lowest energy conformations for both molecules with a value of about ± 30° for this same angle between the O=C-O-C plane and the C-H bond of the iPr group. A survey of crystal structures containing an iPr ester group reveals that the asymmetric conformation is predominant. Although the hydrogen atom on the secondary C atom of the isopropyl group is located at a comparable distance from the carbonyl oxygen in the symmetric and asymmetric fenofibrate (2.52 and 2.28 Å) and the isopropyl clofibrate (2.36 Å) structures, this hydrogen atom participates in a puckered five membered ring arrangement in the latter two that is unlike the planar arrangement found in symmetric fenofibrate (polymorph I). Polar molecular surface area (PSA) values indicate fenofibrate and isopropyl clofibrate are less able to act as acceptors of hydrogen bonds than their corresponding acid derivatives. Surface area calculations show dynamic polar molecular surface area (PSAd

Gold Nanoparticles Size Design and Control by Poly(N,N′-diethylaminoethyl methacrylate)

OpenAIRE

Cortez-Lemus, Norma A.; Licea-Claverie, Angel; Paraguay-Delgado, Francisco; Alonso-Nuñez, Gabriel

2015-01-01

Poly(N,N′-diethylaminoethyl methacrylate) (PDEAEM) with different molecular weights was used to stabilize gold nanoparticles (AuNPs) obtained by in situ reduction of tetrachloroauric acid using citrates under acidic conditions and in organic/alcoholic medium. The influence of the pH value on gold nanoparticle size in the presence of PDEAEM was investigated. Results show that the pH of the reacting mixture has a dramatic effect on the size, polydispersity, and morphology of the resulting AuNPs...

N-doped polypyrrole-based porous carbons for CO{sub 2} capture

Energy Technology Data Exchange (ETDEWEB)

Sevilla, Marta; Valle-Vigon, Patricia; Fuertes, Antonio B. [Instituto Nacional del Carbon (CSIC), P.O. Box 73, 33080 Oviedo (Spain)

2011-07-22

Highly porous N-doped carbons have been successfully prepared by using KOH as activating agent and polypyrrole (PPy) as carbon precursor. These materials were investigated as sorbents for CO{sub 2} capture. The activation process was carried out under severe (KOH/PPy = 4) or mild (KOH/PPy = 2) activation conditions at different temperatures in the 600-800 C range. Mildly activated carbons have two important characteristics: i) they contain a large number of nitrogen functional groups (up to 10.1 wt% N) identified as pyridonic-N with a small proportion of pyridinic-N groups, and ii) they exhibit, in relation to the carbons prepared with KOH/PPy = 4, narrower micropore sizes. The combination of both of these properties explains the large CO{sub 2} adsorption capacities of mildly activated carbon. In particular, a very high CO{sub 2} adsorption uptake of 6.2 mmol.g{sup -1} (0 C) was achieved for porous carbons prepared with KOH/PPy = 2 and 600 C (1700 m{sup 2}.g{sup -1}, pore size {approx} 1 nm and 10.1 wt% N. Furthermore, we observed that these porous carbons exhibit high CO{sub 2} adsorption rates, a good selectivity for CO{sub 2}-N{sub 2} separation and it can be easily regenerated. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Okara promoted acrylamide and carboxymethyl-lysine formation in bakery products.

Science.gov (United States)

Palermo, Mariantonella; Fiore, Alberto; Fogliano, Vincenzo

2012-10-10

Soybeans are widely used in bakery products because of their technological advantages and, recently, soybean-containing products have been marketed as functional foods thanks to several health benefits. Okara is a soybean-based ingredient obtained after elimination of the water-soluble component from ground soybeans. In this paper the effect of okara addition to bakery products on the formation of some potentially harmful Maillard reaction products was evaluated. Cookies obtained by replacing 15% of wheat flour with okara showed a visible browning increase and a more intense Maillard reaction development as shown by higher concentrations of 5-hydroxymethyl-2-furaldehyde (HMF) (+100%), acrylamide (+60%), and carboxymethyl-lysine (CML) (+400%) with respect to the control. This phenomenon could be related to the presence in okara of about 50% of insoluble dietary fiber: the fiber reduces water activity during cooking, thus promoting Maillard reaction. To confirm this hypothesis, cookies obtained by replacing 7% of wheat flour with three different types of dietary fiber (cellulose, chitosan, and pea fiber) were prepared: these experimental cookies showed higher Maillard reaction product concentration with respect to the control and, in particular, HMF and CML values were directly related to the fiber water-holding capacity (WHC). To extend the observation to the food market, a sampling of soybean-containing commercial bakery products was analyzed by comparing the concentrations of Maillard reaction products with those of similar bakery products without soy. Soybean-containing samples showed higher concentrations of acrylamide and CML than corresponding controls.

Magnetic properties of Co-N films deposited by ECR nitrogen/argon plasma with DC negative-biased Co target

Energy Technology Data Exchange (ETDEWEB)

Li, H.; Zhang, Y.C.; Yang, K.; Liu, H.X.; Zhu, X.D., E-mail: xdzhu@ustc.edu.cn; Zhou, H.Y.

2017-06-01

Highlights: • A new method of synthesizing Co-N films containing Co{sub 4}N phase. • Tunable magnetic properties achieved in ECR plasma CVD. • The change of magnetic properties is related to atoms mobility on substrate and the concentration of active species in plasma vapor. - Abstract: By introducing DC negative-biased Co target in the Electron Cyclotron Resonance (ECR) nitrogen/argon plasma, the Co-N films containing Co{sub 4}N phase were synthesized on Si(100) substrate. Effects of processing parameters on magnetic properties of the films are investigated. It is found that magnetic properties of Co-N films vary with N{sub 2}/Ar flow ratio, substrate temperature, and target biasing voltage. The saturation magnetization M{sub s} decreased by increasing the N{sub 2}/Ar gas flow ratio or decreasing target biasing voltage, while the coercive field H{sub c} increased, which is ascribed to the variation of relative concentration for N or Co active species in plasma vapor. The magnetic properties present complex dependency with growth temperature, which is related to the atom mobility on the substrate affected by the growth temperature. This study exhibits a potential of ECR plasma chemical vapor deposition to synthesize the interstitial compounds and tune magnetic properties of films.

Investigation of the phase separation of PNIPAM using infrared spectroscopy together with multivariate data analysis

DEFF Research Database (Denmark)

Munk, Tommy; Baldursdottir, Stefania G.; Hietala, S.

2013-01-01

and Gaussian peak fitting was used to investigate the structural changes in aqueous solutions of a polymer, using poly(N-isopropyl acrylamide) (PNIPAM) in the atactic form and with controlled tacticity as a model system. Subtle spectral changes associated with the dehydration and phase separation upon heating...... included peak shifts, an area ratio change of the amide I band to the amide II band and formation of a new peak in the amide I band were efficiently detected. Dehydration and phase separation of PNIPAM occurred in two temperature ranges, one for the atactic and one for isotactic rich part, both involving...... a complex re-organization of the hydrogen bonds and change of the hydration layer. The changes agreed with existing results from other techniques, and new insights were gained into the effect of controlled tacticity on phase transformation behaviour. The study demonstrates that infrared spectroscopy...

Protein valves prepared by click reaction grafting of poly(N-isopropylacrylamide) to electrospun poly(vinyl chloride) fibrous membranes

Science.gov (United States)

Guo, Jian-Wei; Lin, Zhen-Yu; Chang, Chi-Jung; Lu, Chien-Hsing; Chen, Jem-Kun

2018-05-01

In this study, poly(vinyl chloride) (PVC) was electrospun into fibrous membranes and then reacted with NaN3 to generate azido-terminated PVC fibrous membranes. A propargyl-terminated poly(N-isopropylacrylamide) (PNIPAAm) was also synthesized and then grafted, through click reactions, onto the azido-terminated PVC fiber surface. Protrusion-, scale-, and joint-like structures of the PNIPAAm grafts on the PVC fibers were formed upon increasing the molecular weight of the PNIPAAm grafts. The PNIPAAm-grafted PVC fibrous mats exhibited completely wetted surfaces at 25 °C because of their high roughness. The static water contact angle of the PNIPAAm-grafted PVC fibrous mats reached 140° when the temperature was increased to 45 °C. This thermoresponsive behavior was significantly greater than that of the PNIPAAm grafted on a flat surface. Temperature-responsive membranes were constructed having a pore size of 1.38 μm and applied as protein valves to block and release an antibody (fluorescein-conjugated AffiniPure goat anti-rabbit IgG). At 25 °C, the collection efficiency remained at 94% for antibody concentrations up to 60 ng/L. As the temperature increased to 45 °C, the collection efficiency decreased abruptly, to 4%, when the antibody concentration was greater than 20 ng/L. Accordingly, this system of PNIPAAm-grafted PVC fibers functioned as a protein valve allowing the capture and concentration of proteins.

The ignition delay, laminar flame speed and adiabatic temperature characteristics of n-pentane, n-hexane and n-heptane under O{sub 2}/CO{sub 2} atmosphere

Energy Technology Data Exchange (ETDEWEB)

Zhao, Ran [Huazhong Univ. of Science and Technology, Wuhan (China). State Key Lab. of Coal Combustion; Wuhan Textile Univ. (China). School of Environment and Urban Construction; Liu, Hao; Zhong, Xiaojiao; Wang, Zijian; Jin, Ziqin; Qiu, Jianrong [Huazhong Univ. of Science and Technology, Wuhan (China). State Key Lab. of Coal Combustion; Chen, Yingming [Wuhan Textile Univ. (China). School of Environment and Urban Construction

2013-07-01

Oxy-fuel (O{sub 2}/CO{sub 2}) combustion is one of the several promising new technologies which can realize the integrated control of CO{sub 2}, SO{sub 2}, NO{sub X} and other pollutants. However, when fuels are burned in the high CO{sub 2} concentration environment, the combustion characteristics can be very different from conventional air-fired combustion. Such changes imply that the high CO{sub 2} concentration atmosphere has impacts on the combustion processes. In this paper, the ignition time, laminar flame speed and adiabatic temperature property of C{sub 5} {proportional_to} C{sub 7} n-alkane fuels were studied under both ordinary air atmosphere and O{sub 2}/CO{sub 2} atmospheres over a wide range of CO{sub 2} concentration in the combustion systems. A new unified detailed chemical kinetic model was validated and used to simulate the three liquid hydrocarbon fuel's flame characteristics. Based on the verified model, the influences of various parameters (atmosphere, excess oxygen ratio, O{sub 2} concentration, CO{sub 2} concentration, and alkane type) on the C{sub 5} {proportional_to} C{sub 7} n-alkane's flame characteristics were systematically investigated. It can be concluded that high CO{sub 2} concentration atmosphere has negative effect on n-pentane, n-hexane and n-heptane flame's ignition, laminar flame speed and adiabatic temperature. Besides, this work confirms that high CO{sub 2} concentration atmosphere's chemical effects play a pronounced role on the flame characteristics, especially for the ignition time property.

A study on regional cerebral blood flow measurement by N-isopropyl-p-[I-123]iodoamphetamine

International Nuclear Information System (INIS)

Seki, Hiroyasu

1986-01-01

In vivo characteristics of N-isopropyl-p-[I-123]iodoamphetamine (I-123 IMP) as a potential agent for imaging regional cerebral blood flow (rCBF) were fundamentally studied, and the clinical value of gamma camera rotating SPECT with I-123 IMP was assessed. Brain autoradiography in rats revealed that brain uptake of I-123 IMP is comparable to that described for C-14 iodoantipyrin. In a healthy volunteer, brain uptake was 8.5 % of injected dose at 1.5 hr. Significant uptake of I-123 IMP was observed in the lungs and liver, but not observed in the eyeball or pancreas. Radiation absorbed doses per mCi of I-123 IMP were 0.142 in the brain, 0.178 in the lungs, 0.130 in the liver, 0.038 in the ovaries, 0.027 in the testes, and 0.042 in the total body. A rotating gamma camera for SPECT gave the same linear response to radioactivity as a ring detector, although the latter had better sensitivity and resolution than the former. An increased rCBF was observed with physiological stimulation including left hand movement, reading, and listening, providing three-dimensional mapping of regional cerebral function for kinesthesia. Fifty-three measurements of rCBF were clinically acquired in 42 patients with cerebrovascular disorder. Mean rCBF ranged from 11 to 40 ml/100 g/min. SPECT with I-123 IMP had a significantly high ability to detect ischemic lesions compared with X-ray CT (83 % vs. 41 %). These results indicate the potential benefits of this modality in evaluating cerebral pathophysiology, treatment efficacy, and surgical indications. (Namekawa, K.)

Lyoluminescence of tris (hydroxymethyl) aminomethane in gamma dosimetry

International Nuclear Information System (INIS)

Azorin, J.; Gutierrez, A.; Guadarrama, L.

1986-01-01

Gamma dosimetry using lyoluminescence (LL) has advantages over other conventional systems because of its low cost and simplicity of use. Results of the investigation of the LL properties of tris (hydroxymethyl) aminomethane irradiated with 60 Co gamma radiation are presented and compared with the results of the LL of mannose and sucrose. Tris on dissolution in luminol shows a higher LL response than that of mannose and lower than that of sucrose, and has the highest stability of the three systems. The LL response of tris was linear in the range 5 Gy to 1kGy and showed no fading during one week. A comparison with the results of other authors as well as with measurements by ESR techniques are also reported. From these results we conclude that tris (hydroxymethyl) aminomethane on dissolution in luminol provides a LL dosimetric system useful for gamma dosimetry in the radiation processing of foods. (author)

Study on the Soy Protein-Based Wood Adhesive Modified by Hydroxymethyl Phenol

Directory of Open Access Journals (Sweden)

Hong Lei

2016-07-01

Full Text Available To explain the reason why using phenol-formaldehyde (PF resin improves the water resistance of soy-based adhesive, the performance of soy-based adhesive cross-linked with hydroxymethyl phenol (HPF and the reaction between HPF and a common dipeptide N-(2-l-alanyl-l-glutamine (AG being used as a model compound were studied in this paper. The DSC and DMA results indicated the reaction between HPF and soy-based adhesive. The soy-based adhesive cross-linked with HPF cured at a lower temperature than the adhesive without HPF. The former showed better mechanical performance and heat resistance than the latter. The ESI-MS, FT-IR and 13C-NMR results proved the reaction between HPF and AG. Because of the existence of branched ether groups in the 13C-NMR results of HPF/AG, the reaction between HPF and AG might mainly happened between hydroxymethyl groups and amino groups under a basic condition.

New optically active and thermally stable poly(amide-imide)s containing N,N'-(Bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic)-bis-L-alanine and aromatic diamines: synthesis and characterization

Energy Technology Data Exchange (ETDEWEB)

Faghihi, Khalil; Absalar, Morteza; Hajibeygi, Mohsen [Arak University (Iran, Islamic Republic of). Faculty of Science. Organic Polymer Chemistry Research Lab.

2009-07-01

Five new optically active poly(amide-imide)s (PAIs) 6a-e were prepared by direct polycondensation reaction of the newly synthesized N,N'-(bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetra carboxylic)-bis-L-alanine 4 with various aromatic diamines 5a-e using polar aprotic solvents such as N-methyl-2-pyrrolidone (NMP). In this technique triphenyl phosphite (TPP) and pyridine were used as condensing agents to form poly(amide-imide)s through the N-phosphonium salts of pyridine. All of the polymers were obtained in quantitative yields with inherent viscosities between 0.29-0.46 dL g{sup -1} and were highly soluble in polar aprotic solvents such as N,N-dimethyl acetamide (DMAc), N,N-dimethyl formamide (DMF), dimethyl sulfoxide (DMSO), N-methyl- 2-pyrrolidone (NMP) and solvents such as sulfuric acid. They were fully characterized by means of {sup 1}H NMR, FTIR spectroscopy, elemental analyses, inherent viscosity, solubility test, specific rotation and thermal properties of these polymers were investigated using thermogravimetric analysis techniques (TGA and DTG). (author)

Extraction Separation of Am(III) and Eu(III) with Thermo-sensitive Gel introducing TPEN Derivatives

International Nuclear Information System (INIS)

Kenji Takeshita; Yoshio Nakano; Tatsuro Matsumura; Atsunori Mori

2008-01-01

A thermal-swing chromatographic process using a thermo-sensitive gel co-polymerized with NIPA (N-isopropyl-acrylamide) and TPPEN (N,N,N',N'-tetrakis(4-propenyl-oxy-2-pyridyl-methyl)ethylenediamine) was studied for the separation of Am(III) from Eu(III). First, the radiolysis of the TPPEN-NIPA gel was tested by the γ-ray irradiation and the α nuclide adsorption. The extraction separation of Am(III) was not influenced in the radioactive environment of the proposed process. Next, the TPPEN-NIPA gel was immobilized in porous silica particles and the applicability of the gel-immobilized silica to the proposed process was tested. Am(III) was extracted selectively in the gel-immobilized silica at 5 deg. C and the separation factor of Am(III) over Eu(III) was evaluated to be 3.7. The distribution ratio of Am(III) was reduced to less than 1/20 by increasing temperature from 5 deg. C to 40 deg. C. These results indicate that the TPPEN-NIPA gel is applicable to the thermal-swing chromatographic process for the minor actinide recovery. (authors)

Predicting Avian Influenza Co-Infection with H5N1 and H9N2 in Northern Egypt

Directory of Open Access Journals (Sweden)

Sean G. Young

2016-09-01

Full Text Available Human outbreaks with avian influenza have been, so far, constrained by poor viral adaptation to non-avian hosts. This could be overcome via co-infection, whereby two strains share genetic material, allowing new hybrid strains to emerge. Identifying areas where co-infection is most likely can help target spaces for increased surveillance. Ecological niche modeling using remotely-sensed data can be used for this purpose. H5N1 and H9N2 influenza subtypes are endemic in Egyptian poultry. From 2006 to 2015, over 20,000 poultry and wild birds were tested at farms and live bird markets. Using ecological niche modeling we identified environmental, behavioral, and population characteristics of H5N1 and H9N2 niches within Egypt. Niches differed markedly by subtype. The subtype niches were combined to model co-infection potential with known occurrences used for validation. The distance to live bird markets was a strong predictor of co-infection. Using only single-subtype influenza outbreaks and publicly available ecological data, we identified areas of co-infection potential with high accuracy (area under the receiver operating characteristic (ROC curve (AUC 0.991.

Efficient synthesis of benzothiazine and acrylamide compounds

Energy Technology Data Exchange (ETDEWEB)

Souza, Ana Maria Alves; Walfrido, Simone Torres Padua; Leite, Lucia Fernanda Costa; Lima, Maria Carmo Alves; Galdino, Suely Lins; Pitta, Ivan Rocha [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Antibioticos; Barbosa Filho, Jose Maria [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil); Simone, Carlos Alberto de; Ellena, Javier Alcides, E-mail: irpitta@gmail.co [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Fisica

2010-07-01

This article describes the synthesis of the new (2Z)-2-(4-methoxybenzylidene)-6-nitro-4H -benzo[1,4]thiazine-3-one, (2Z)-2-(4-methoxybenzylidene)-4-methyl-6-nitro-4H-benzo[1,4]thiazine-3-one, (2Z)-6-amino-2-(4-methoxybenzylidene)-4H -benzo[1,4]thiazine-3-one, (2Z)-6-butylamino-2-(4-methoxybenzylidene)-4-methyl-4H-benzo[1,4] -thiazine-3-one and (2E)-N-alkyl-N-(2-hydroxy-5-nitrophenyl) -3-phenylacrylamides and the spectroscopic data. The arylidenebenzothiazine compounds were prepared using the Knoevenagel condensation with substituted benzaldehydes in the presence of sodium methoxide in DMF. The presence of a nitro substituent in the 4-position, water and a slightly acid reaction medium in this condensation caused the rupture of the benzothiazine ring and subsequent formation of the phenylacrylamide compounds. A crystallographic data was presented for (2E)-3-(4-bromophenyl)-N-dodecyl-N -(2-hydroxy-5-nitrophenyl) acrylamide. (author)

Efficient synthesis of benzothiazine and acrylamide compounds

International Nuclear Information System (INIS)

Souza, Ana Maria Alves; Walfrido, Simone Torres Padua; Leite, Lucia Fernanda Costa; Lima, Maria Carmo Alves; Galdino, Suely Lins; Pitta, Ivan Rocha; Simone, Carlos Alberto de; Ellena, Javier Alcides

2010-01-01

This article describes the synthesis of the new (2Z)-2-(4-methoxybenzylidene)-6-nitro-4H -benzo[1,4]thiazine-3-one, (2Z)-2-(4-methoxybenzylidene)-4-methyl-6-nitro-4H-benzo[1,4]thiazine-3-one, (2Z)-6-amino-2-(4-methoxybenzylidene)-4H -benzo[1,4]thiazine-3-one, (2Z)-6-butylamino-2-(4-methoxybenzylidene)-4-methyl-4H-benzo[1,4] -thiazine-3-one and (2E)-N-alkyl-N-(2-hydroxy-5-nitrophenyl) -3-phenylacrylamides and the spectroscopic data. The arylidenebenzothiazine compounds were prepared using the Knoevenagel condensation with substituted benzaldehydes in the presence of sodium methoxide in DMF. The presence of a nitro substituent in the 4-position, water and a slightly acid reaction medium in this condensation caused the rupture of the benzothiazine ring and subsequent formation of the phenylacrylamide compounds. A crystallographic data was presented for (2E)-3-(4-bromophenyl)-N-dodecyl-N -(2-hydroxy-5-nitrophenyl) acrylamide. (author)

N-isopropylacrylamide-based fine-dispersed thermosensitive ferrogels obtained via in-situ technique.

Science.gov (United States)

Korotych, O; Samchenko, Yu; Boldeskul, I; Ulberg, Z; Zholobak, N; Sukhodub, L

2013-03-01

Thermosensitive hydrogels with magnetic properties (ferrogels) are very promising for medical application, first of all, for the design of targeted delivery systems with controlled release of drugs and for magnetic hyperthermia and chemotherapy treatment of cancer. These magnetic hydrogels could be obtained using diverse techniques: ex- and in-situ syntheses. The present work is devoted to the study of magnetite (Fe(3)O(4)) formation inside the nanoreactors of (co)polymeric hydrogels. Polymeric templates (hydrogel films and fine-dispersed hydrogels) used for obtaining ferrogels were based on acrylic monomers: thermosensitive N-isopropylacrylamide, and hydrophilic acrylamide. Covalent cross-linking was accomplished using bifunctional monomer N,N'-methylenebisacrylamide. Influence of hydrophilic-lipophilic balance of polymeric templates and concentration of iron cations on the magnetite formation were investigated along with the development of ferrogel preparation technique. Cytotoxicity, physical and chemical properties of obtained magnetic hydrogels have been studied in this work. Copyright © 2012 Elsevier B.V. All rights reserved.

Temperature-responsive nanogel multilayers of poly(N-vinylcaprolactam) for topical drug delivery.

Science.gov (United States)

Zavgorodnya, Oleksandra; Carmona-Moran, Carlos A; Kozlovskaya, Veronika; Liu, Fei; Wick, Timothy M; Kharlampieva, Eugenia

2017-11-15

We report nanothin temperature-responsive hydrogel films of poly(N-vinylcaprolactam) nanoparticles (νPVCL) with remarkably high loading capacity for topical drug delivery. Highly swollen (νPVCL) n multilayer hydrogels, where n denotes the number of nanoparticle layers, are produced by layer-by-layer hydrogen-bonded assembly of core-shell PVCL-co-acrylic acid nanoparticles with linear PVPON followed by cross-linking of the acrylic acid shell with either ethylene diamine (EDA) or adipic acid dihydrazide (AAD). We demonstrate that a (νPVCL) 5 film undergoes dramatic and reversible swelling up to 9 times its dry thickness at pH = 7.5, indicating 89v/v % of water inside the network. These hydrogels exhibit highly reversible ∼3-fold thickness changes with temperature variations from 25 to 50°C at pH = 5, the average pH of human skin. We also show that a (νPVCL) 30 hydrogel loaded with ∼120µgcm -2 sodium diclofenac, a non-steroidal anti-inflammatory drug used for osteoarthritis pain management, provides sustained permeation of this drug through an artificial skin membrane for up to 24h at 32°C (the average human skin surface temperature). The cumulative amount of diclofenac transported at 32°C from the (νPVCL) 30 hydrogel after 24h is 12 times higher than that from the (νPVCL) 30 hydrogel at 22°C. Finally, we demonstrate that the (νPVCL) hydrogels can be used for multiple drug delivery by inclusion of Nile red, fluorescein and DAPI dyes within the νPVCL nanoparticles prior to hydrogel assembly. Using confocal microscopy we observed the presence of separate dye-loaded νPVCL compartments within the hydrogel matrix with all three dyes confined to the nanogel particles without intermixing between the dyes. Our study provides opportunity for development of temperature-responsive multilayer hydrogel coatings made via the assembly of core-shell nanogel particles which can be used for skin-sensitive materials for topical drug delivery. Copyright © 2017

Poly(N-vinyl-2-pyrrolidone)-stabilized palladium-platinum nanoparticles-catalyzed hydrolysis of ammonia borane for hydrogen generation

Science.gov (United States)

Rakap, Murat

2015-02-01

The catalytic use of highly efficient poly(N-vinyl-2-pyrrolidone)-stabilized palladium-platinum nanoparticles (4.2 ± 1.9 nm) in the hydrolysis of ammonia-borane is reported. The catalyst is prepared by co-reduction of two metal ions in ethanol/water mixture by an alcohol reduction method and characterized by transmission electron microscopy, X-ray photoelectron spectroscopy and UV-Vis spectroscopy. They are recyclable and highly active for hydrogen generation from the hydrolysis of ammonia-borane even at very low concentrations and temperature, providing a record numbers of average turnover frequency value (125 mol H2/mol cat.min-1) and maximum hydrogen generation rate (3468 L H2 min-1 (mol cat)-1). They also provide activation energy of 51.7 ± 2 kJ/mol for the hydrolysis of ammonia borane.

Controlling acrylamide in French fry and potato chip models and a mathematical model of acrylamide formation: acrylamide: acidulants, phytate and calcium.

Science.gov (United States)

Park, Yeonhwa; Yang, Heewon; Storkson, Jayne M; Albright, Karen J; Liu, Wei; Lindsay, Robert C; Pariza, Michael W

2005-01-01

We previously reported that in potato chip and French fry models, the formation of acrylamide can be reduced by controlling pH during processing steps, either by organic (acidulants) or inorganic acids. Use of phytate, a naturally occurring chelator, with or without Ca++ (or divalent ions), can reduce acrylamide formation in both models. However, since phytate itself is acidic, the question remains as to whether the effect of phytate is due to pH alone or to additional effects. In the French fry model, the effects on acrylamide formation of pH, phytate, and/or Ca++ in various combinations were tested in either blanching or soaking (after blanching) steps. All treatments significantly reduced acrylamide levels compared to control. Among variables tested, pH may be the single most important factor for reducing acrylamide levels, while there were independent effects of phytate and/or Ca++ in this French fry model. We also developed a mathematical formula to estimate the final concentration of acrylamide in a potato chip model, using variables that can affect acrylamide formation: glucose and asparagine concentrations, cut potato surface area and shape, cooking temperature and time, and other processing conditions.

Articulación de fuentes para la administración del dominio .co: ¿inserción de Colombia en el entorno internacional?

Directory of Open Access Journals (Sweden)

Daniel Peña Valenzuela

2008-11-01

Full Text Available La Ley 1065 de 2006, mediante la cual se reguló específicamente la administración del nombre de dominio .co, estableció que este constituye un recurso de interés público del sector de las telecomunicaciones, cuya administración debe ejercerla el Ministerio de Comunicaciones en ejercicio de una función administrativa, la cual puede ser delegada en un particular. La consagración de la administración del dominio .co como una función administrativa parece ir en contra de la naturaleza privada con la que fueron concebidos los nombres de dominio, por lo cual no es claro si es posible respetar y preservar la especialidad de los nombres de dominio a partir del marco normativo colombiano. Este artículo pretende responder este interrogante, para lo cual será necesario identificar todos los instrumentos que hacen parte de dicho marco normativo y cómo se articulan, para determinar, a partir de ello, el funcionamiento del modelo colombiano.

APLICACIÓN DE LA METODOLOGÍA DE SUPERFICIE DE RESPUESTA EN UN PROCESO DE ABSORCIÓN DEL CO2 DE UN BIOGÁS EN UNA SOLUCIÓN ALCALINA

OpenAIRE

MUÑOZ SIERRA, JULIÁN DAVID; CAMARGO TRILLOS, DIEGO ALEJANDRO; GALLEGO SUÁREZ, DARÍO

2009-01-01

Se empleó un diseño factorial 2³ ampliado a central compuesto para investigar los efectos de las variables relación [CO3=/HCO3−], presión inicial del gas y temperatura del sistema gas-líquido, en el proceso de absorción de CO2 en una solución alcalina de carbonato-bicarbonato de sodio, utilizando un biogás simulado como mezcla gaseosa problema. Se encontró una significante influencia de la relación de concentración en el proceso de remoción del dióxido de carbono, obteniéndose un modelo de su...

Phytoremediation potential of Arabidopsis with reference to acrylamide and microarray analysis of acrylamide-response genes.

Science.gov (United States)

Gao, Jian-Jie; Peng, Ri-He; Zhu, Bo; Wang, Bo; Wang, Li-Juan; Xu, Jing; Sun, Miao; Yao, Quan-Hong

2015-10-01

Acrylamide (ACR) is a widely used industrial chemical. However, it is a dangerous compound because it showed neurotoxic effects in humans and act as reproductive toxicant and carcinogen in many animal species. In the environment, acrylamide has high soil mobility and may travel via groundwater. Phytoremediation is an effective method to remove the environmental pollutants, but the mechanism of plant response to acrylamide remains unknown. With the purpose of assessing remediation potentials of plants for acrylamide, we have examined acrylamide uptake by the model plant Arabidopsis grown on contaminated substrates with high performance liquid chromatography (HPLC) analysis. The result revealed that acrylamide could be absorbed and degraded by Arabidopsis. Further microarray analysis showed that 527 transcripts were up-regulated within 2-days under acrylamide exposure condition. We have found many potential acrylamide-induced genes playing a major role in plant metabolism and phytoremediation. Copyright © 2015 Elsevier Inc. All rights reserved.

13C n.m.r. study of solvation mechanisms in the radiation-induced polymerization of vinyl ethers

International Nuclear Information System (INIS)

Deffieux, A.; Subira, F.; Stannett, V.T.

1984-01-01

A 13 C n.m.r. study of the microstructure of ethyl vinyl ether (EVE) and isopropyl vinyl ether (IPVE) polymers prepared under various experimental conditions and using chemical or γ-ray initiation has been made. Long stereo-sequence assignments were conducted for poly EVE allowing determination of the configurational statistics of propagation in the radiation-induced polymerization of EVE in low polar solvents. Stereo-sequence intensities are found in good agreement with the Markovian model. The results are considered as further support for the occurrence of a specific interaction between the growing active centres and the polymer chains. In the case of IPVE polymers much more important overlappings of the resonance patterns are observed thus preventing any similar detailed study. (author)

Thermoresponsive Poly(2-oxazoline) Molecular Brushes by Living Ionic Polymerization: Kinetic Investigations of Pendant Chain Grafting and Cloud Point Modulation by Backbone and Side Chain Length Variation

KAUST Repository

Zhang, Ning

2012-04-17

Molecular brushes of poly(2-oxazoline)s were prepared by living anionic polymerization of 2-iso-propenyl-2-oxazoline to form the backbone and subsequent living cationic ring-opening polymerization of 2-n- or 2-iso-propyl-2-oxazoline for pendant chain grafting. In situ kinetic studies indicate that the initiation efficiency and polymerization rates are independent from the number of initiator functions per initiator molecule. This was attributed to the high efficiency of oxazolinium salt and the stretched conformation of the backbone, which is caused by the electrostatic repulsion of the oxazolinium moieties along the macroinitiator. The resulting molecular brushes showed thermoresponsive properties, that is, having a defined cloud point (CP). The dependence of the CP as a function of backbone and side chain length as well as concentration was studied. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation and characterization of reactive blends of poly(lactic acid), poly(ethylene-co-vinyl alcohol), and poly(ethylene-co-glycidyl methacrylate)

International Nuclear Information System (INIS)

Warangkhana, Phromma; Rathanawan, Magaraphan; Jana Sadhan, C.

2015-01-01

The ternary blends of poly(lactic acid) (PLA), poly(ethylene-co-vinyl alcohol) (EVOH), and poly(ethylene-co-glycidyl methacrylate) (EGMA) were prepared. The role of EGMA as a compatibilizer was evaluated. The weight ratio of PLA:EVOH was 80:20 and the EGMA loadings were varied from 5-20 phr. The blends were characterized as follows: thermal properties by differential scanning calorimetry, morphology by scanning electron microscopy, and mechanical properties by pendulum impact tester, and universal testing machine. The glass transition temperature of PLA blends did not change much when compared with that of PLA. The blends of PLA/EGMA and EVOH/EGMA showed EGMA dispersed droplets where the latter led to poor impact properties. However, the tensile elongation at break and tensile toughness substantially increased upon addition of EGMA to blends of PLA and EVOH. It was noted in tensile test samples that both PLA and EVOH domains fibrillated significantly to produce toughness

Preparation and characterization of reactive blends of poly(lactic acid), poly(ethylene-co-vinyl alcohol), and poly(ethylene-co-glycidyl methacrylate)

Energy Technology Data Exchange (ETDEWEB)

Warangkhana, Phromma; Rathanawan, Magaraphan, E-mail: rathanawan.k@chula.ac.th [Chulalongkorn University, Petroleum and Petrochemical College - Bangkok (Thailand); Jana Sadhan, C., E-mail: janas@uakron.edu [The University of Akron, Department of Polymer Engineering, Ohio (United States)

2015-05-22

The ternary blends of poly(lactic acid) (PLA), poly(ethylene-co-vinyl alcohol) (EVOH), and poly(ethylene-co-glycidyl methacrylate) (EGMA) were prepared. The role of EGMA as a compatibilizer was evaluated. The weight ratio of PLA:EVOH was 80:20 and the EGMA loadings were varied from 5-20 phr. The blends were characterized as follows: thermal properties by differential scanning calorimetry, morphology by scanning electron microscopy, and mechanical properties by pendulum impact tester, and universal testing machine. The glass transition temperature of PLA blends did not change much when compared with that of PLA. The blends of PLA/EGMA and EVOH/EGMA showed EGMA dispersed droplets where the latter led to poor impact properties. However, the tensile elongation at break and tensile toughness substantially increased upon addition of EGMA to blends of PLA and EVOH. It was noted in tensile test samples that both PLA and EVOH domains fibrillated significantly to produce toughness.

Preparation and Characterization of Facilitated Transport Membranes Composed of Chitosan-Styrene and Chitosan-Acrylonitrile Copolymers Modified by Methylimidazolium Based Ionic Liquids for CO2 Separation from CH4 and N2

Directory of Open Access Journals (Sweden)

Ksenia V. Otvagina

2016-06-01

Full Text Available CO2 separation was found to be facilitated by transport membranes based on novel chitosan (CS–poly(styrene (PS and chitosan (CS–poly(acrylonitrile (PAN copolymer matrices doped with methylimidazolium based ionic liquids: [bmim][BF4], [bmim][PF6], and [bmim][Tf2N] (IL. CS plays the role of biodegradable film former and selectivity promoter. Copolymers were prepared implementing the latest achievements in radical copolymerization with chosen monomers, which enabled the achievement of outstanding mechanical strength values for the CS-based membranes (75–104 MPa for CS-PAN and 69–75 MPa for CS-PS. Ionic liquid (IL doping affected the surface and mechanical properties of the membranes as well as the gas separation properties. The highest CO2 permeability 400 Barrers belongs to CS-b-PS/[bmim][BF4]. The highest selectivity α (CO2/N2 = 15.5 was achieved for CS-b-PAN/[bmim][BF4]. The operational temperature of the membranes is under 220 °C.

Fabrication, thermal properties and thermal stabilities of microencapsulated n-alkane with poly(lauryl methacrylate) as shell

International Nuclear Information System (INIS)

Qiu, Xiaolin; Lu, Lixin; Wang, Ju; Tang, Guoyi; Song, Guolin

2015-01-01

Highlights: • Microencapsulation of octadecane and paraffin by crosslinked poly(lauryl methacrylate). • Octadecane microcapsules have a melting enthalpy of about 118 J g −1 . • Weight loss temperatures of the microcapsules were increased by 67 °C and 28 °C. • Phase change enthalpies decreased by around 10 wt% after 500 thermal cycles. • Foams with microcapsules can be applied for passive temperature control. - Abstract: Microencapsulation of n-octadecane or paraffin with poly(lauryl methacrylate) (PLMA) shell was performed by a suspension-like polymerization. The polymer shell was crosslinked by pentaerythritol tetraacrylate (PETRA). The surface morphologies of microcapsules were investigated by scanning electron microscopy (SEM). Phase change properties, thermal reliabilities and thermal stabilities of microcapsules were determined by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The n-octadecane microcapsule exhibits higher melting enthalpy (118.0 J g −1 ) and crystallization enthalpy (108.3 J g −1 ) compared with the paraffin microcapsule. The thermal resistant temperatures were enhanced by more than 25 °C when n-alkanes were microencapsulated by PLMA. The PCM contents of microcapsules decreased by less than 4 wt% and 6 wt% after 500 and 1000 thermal cycles, respectively. Heat-up experiments indicated that microcapsule-treated foams exhibited upgraded thermal regulation capacities. Consequently, microencapsulated n-octadecane or paraffin with PLMA as shell possesses good potentials for heat storage and thermal regulation.

A first principles calculations of structural, electronic, magnetic and dynamical properties of mononitrides FeN and CoN

International Nuclear Information System (INIS)

Soni, Himadri R.; Mankad, Venu; Gupta, Sanjeev K.; Jha, Prafulla K.

2012-01-01

Highlights: ► We present spin dependent bandstructure, structural and magnetic moment of FeN/CoN. ► The PDC, PHDOS, spin effect on phonons suggests ZB is preferred at ambient pressure. ► Spin calculation offers an opportunity to understand the role of spin on phonons. - Abstract: Using first principles density functional theoretical calculations, the present paper reports a systematic nonspin and spin polarized total energy calculations of the lattice dynamical and a number of other properties such as band structure, structural and magnetic moment of two mononitrides FeN and CoN. The phonon dispersion curves and phonon density of states in the case of FeN and CoN have been determined for the first time and discussed. The structural and dynamical calculations suggest that the zinc blende structure is preferred at ambient pressure for both compounds. The rocksalt FeN has a nonzero magnetic moment while for FeN in zinc blende phase, it is either zero or very small. The zinc blende phase for both compounds is nonmagnetic. The spin calculation offers an intensive opportunity to understand the role of spin on the phonon properties of two mononitrides. Majority of the modes are sensitive to the effect of spin due to the modification of lattice constant. In this work we reveal that spin modifies the interionic interactions and local structure and leads to a flexible lattice which can be used for the functional materials design.

Morphological, dielectric and electric conductivity characteristics of clay-containing nanohybrids of Poly(N-Vinyl Carbazole) and Polypyrrole

CSIR Research Space (South Africa)