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1

Crosslinkable poly(vinyl acetate) emulsions for wood adhesive  

Microsoft Academic Search

Purpose – The purpose of this paper is to enhance the water resistance and the heat resistance of poly(vinyl acetate) (PVAc) emulsion adhesive, by providing the emulsion with controllable thermosetting capability. Design\\/methodology\\/approach – Emulsion polymerisation was used to synthesise PVAc\\/VeoVa 10 copolymers with varying proportions of acetoacetoxyethyl methacrylate (AAEM) incorporated in the copolymer chains. The AAEM component provided sites for

Jia Lu; Allan J. Easteal; Neil R. Edmonds

2011-01-01

2

MECHANICAL PROPERTIES OF BLENDS OF PAMAM DENDRIMERS WITH POLY(VINYL CHLORIDE) AND POLY(VINYL ACETATE)  

EPA Science Inventory

Hybrid blends of poly(amidoamine) PAMAM dendrimers with two linear high polymers, poly(vinyl chloride), PVC, and poly(vinyl acetate), PVAc, are reported. The interaction between the blend components was studied using dynamic mechanical analysis, xenon nuclear magnetic resonacne ...

3

Oral 4-week and 13-week toxicity studies of polyvinyl acetate vinyl laurate copolymer in rats.  

PubMed

Polyvinyl acetate vinyl laurate copolymer (PVAcVL) is a useful component of gum base for chewing gum production. The safety of PVAcVL was examined in a 4-week and a 13-week oral toxicity study in rats. Finely powdered PVAcVL was administered with the diet at levels of 1.25%, 2.0% and 5% in the 4-week study and 1.25%, 2.5% and 5% in the 13-week study. There were no treatment related effects on mortality, bodyweight gains feed efficiency, ophthalmoscopic findings, hematological and clinical chemical parameters, neurobehavioral observations as well as gross and histopathological changes of standard organs and tissues. The highest dose tested in the 13-week study (3783 and 4396mg/kgbw/d for males and females, respectively) proved to be a NOAEL. PMID:24932800

Messinger, Horst; Bär, Albert

2014-10-01

4

Photochemical degradation study of polyvinyl acetate paints used in artworks by Py–GC/MS  

PubMed Central

Photochemical degradation of commercial polyvinyl acetate (PVAc) homopolymer and PVAc paints mixed with burnt umber, cobalt blue, cadmium red dark, nickel azo yellow and titanium white commonly used for artworks were studied by pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) and Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR). Py–GC/MS with single-shot technique was used for the characterization of the thermal degradation of PVAc at different temperatures, while the double-shot technique of Py–GC/MS was used to reveal the differences in the specimens before and after UV ageing, including the changes of detectable amounts of deacetylation product – acetic acid and plasticizers such as diethyl phthalate (DEP). Furthermore, the relative concentration of the pyrolysis products of the paint samples could be measured and compared in the second step of the double-shot Py–GC/MS, which are highly dependent on the presence of pigments and the ageing status of PVAc paints. PMID:23024446

Wei, Shuya; Pintus, Valentina; Schreiner, Manfred

2012-01-01

5

Evaluation of CO2-Philicity of Poly(vinyl acetate) and Poly(vinyl acetate-alt-maleate) Copolymers through Molecular Modeling and Dissolution Behavior Measurement.  

PubMed

Multiscale molecular modeling and dissolution behavior measurement were both used to evaluate the factors conclusive on the CO2-philicity of poly(vinyl acetate) (PVAc) homopolymer and poly(vinyl acetate-alt-maleate) copolymers. The ab initio calculated interaction energies of the candidate CO2-philic molecule models with CO2, including vinyl acetate dimer (VAc), dimethyl maleate (DMM), diethyl maleate (DEM), and dibutyl maleate (DBM), showed that VAc was the most CO2-philc segment. However, the cohesive energy density, solubility parameter, Flory-Huggins parameter, and radial distribution functions calculated by using the molecular dynamics simulations for the four polymer and polymer-CO2 systems indicated that poly(VAc-alt-DBM) had the most CO2-philicity. The corresponding polymers were synthesized by using free radical polymerization. The measurement of cloud point pressures of the four polymers in CO2 also demonstrated that poly(VAc-alt-DBM) had the most CO2-philicity. Although copolymerization of maleate, such as DEM or DBM, with PVAc reduced the polymer-CO2 interactions, the weakened polymer-polymer interaction increased the CO2-philicity of the copolymers. The polymer-polymer interaction had a significant influence on the CO2-philicity of the polymer. Reduction of the polymer-polymer interaction might be a promising strategy to prepare the high CO2-philic polymers on the premise that the strong polymer-CO2 interaction could be maintained. PMID:25599262

Hu, Dongdong; Sun, Shaojun; Yuan, Peiqing; Zhao, Ling; Liu, Tao

2015-02-19

6

Poly(ethylene oxide) Dynamics in Blends with Poly(vinyl acetate)  

NASA Astrophysics Data System (ADS)

^2H NMR relaxation measurements were performed to study the segmental dynamics of perdeuteropoly(ethylene oxide) (d4PEO) in miscible blends with poly(vinyl acetate) (PVAc). For two compositions (2% and 50% d4PEO), spin-lattice relaxation times were measured in a temperature range well above Tg. Over the temperature range studied, the segmental dynamics of the PEO component in 2% PEO/PVAc blend is almost the same as that in 3% PEO/PMMA blend reported by Lutz et al. (Macromolecules 2003, 36, 1724-1730), even though the Tg of PVAc is 100K lower than that of PMMA. In the 2% d4PEO blend, the segmental dynamics of PEO is 9 orders of magnitude faster than PVAc segmental dynamics at the blend Tg. For the two compositions studied, segmental dynamics of the PEO component can be well described by L-M model with a self-concentration of 0.3. By comparing the segmental correlation times of the PEO component with viscoelastic shift factors reported by Urakawa et al. (J. Non-Crystalline Solids 352, 2006 5042-5049), it is found that the temperature dependence of the segmental dynamics of the PEO component is weaker than the temperature dependence of the PEO terminal dynamics.

Zhao, Junshu; Ediger, Mark

2007-03-01

7

Time dependence of the segmental relaxation time of poly(vinyl acetate)-silica nanocomposites  

NASA Astrophysics Data System (ADS)

The aging-time dependence of the segmental relaxation time of poly(vinyl acetate) (PVAc) in the glassy state is investigated in the bulk polymer and its nanocomposites with silica (SiO2). These systems present identical segmental dynamics, when this is probed in the equilibrium supercooled liquid by broadband dielectric spectroscopy. An acceleration of the physical aging process of PVAc with SiO2 was detected by monitoring the enthalpy recovery through differential scanning calorimetry. The segmental relaxation time during physical aging, followed by means of BDS, has been shown to increase more rapidly the higher the SiO2 concentration in PVAc is. Thermally stimulated depolarization current experiments show that this is the case over the whole probed glassy state. This means that nanocomposites displaying a relatively slow segmental mobility evolve toward equilibrium more rapidly than the bulk. Furthermore, despite the faster increase in the relaxation time with aging time, so-called self-retardation, the nanocomposites and their bulk counterpart reach the same values of equilibrium relaxation time. These findings not only confirm the assumption of identical equilibrium dynamics even in the aging regime for all nanocomposites and bulk polymers, proposed in previous works, but also highlight the fact that the physical aging rate is not determined solely by the polymer segmental dynamics, the amount of interface being an additional relevant parameter.

Boucher, Virginie M.; Cangialosi, Daniele; Alegría, Angel; Colmenero, Juan

2012-10-01

8

Method development for compositional analysis of low molecular weight poly(vinyl acetate) by matrix-assisted/laser desorption-mass spectrometry and its application to analysis of chewing gum.  

PubMed

The influence of the sample preparation parameters (the choice of the solvent and of the matrix:analyte ratio) was investigated and optimal conditions were established for MALDI mass spectrometry analysis of the pristine low molecular weight polyvinyl acetate (PVAc). It was demonstrated that comparison of polymer's and solvent's Hansen solubility parameters could be used as a guide when choosing the solvent for MALDI sample preparation. The highest intensity PVAc signals were obtained when ethyl acetate was used as a solvent along with the lowest matrix-analyte ratio (2,5-dihydroxybenzoic acid was used as a matrix in all experiments). The structure of the PVAc was established with high accuracy using the matrix-assisted laser desorption/ionization-Fourier transform mass spectrometry (MALDI-FTMS) analysis. It was demonstrated that PVAc undergoes unimolecular decomposition by losing acetic acid molecules from its backbone under the conditions of FTMS measurements. Number and weight average molecular weights as well as polydispersity indices were determined with both MALDI-TOF and MALDI-FTMS methods. The sample preparation protocol developed was applied to the analysis of a chewing gum and the molecular weight and structure of the polyvinyl acetate present in the sample were established. Thus, it was shown that optimized MALDI mass spectrometry could be used successfully for characterization of polyvinyl acetate in commercially available chewing gum. PMID:24745742

Tisdale, Evgenia; Wilkins, Charles

2014-04-11

9

Temperature divergence of the dynamics of a poly(vinyl acetate) glass: Dielectric vs. mechanical behaviors  

NASA Astrophysics Data System (ADS)

The dynamics of glass forming liquids as the glass transition temperature (Tg) is traversed has become of special interest because of the continuing question as to whether or not the dynamics diverge towards an ideal glass transition/Kauzmann temperature or if the apparent Vogel-Fulcher-Tammann (VFT) divergence is lost as one goes below the conventional Tg but remains in equilibrium. Here we examine the response of a poly(vinyl acetate) PVAc polymer glass-former using both dielectric and mechanical methods in the vicinity of Tg. Isothermal measurements were performed to study the aging behavior of the PVAc and to assure that the equilibrium state was achieved for temperatures as much as 16 K below the calorimetric Tg. Surprisingly, we found that the mechanical response took much longer to age into its equilibrium than did the dielectric response. Also, the temperature dependence of the time-temperature shift factors obtained from the two methods is different and the dielectric response shows a turnover to an apparent Arrhenius behavior rather than a continuation of the VFT extrapolated divergence at the lowest temperatures tested.

Zhao, Jing; McKenna, Gregory B.

2012-04-01

10

Structural and mechanical properties of "peelable" organoaqueous dispersions with partially hydrolyzed poly(vinyl acetate)-borate networks: applications to cleaning painted surfaces.  

PubMed

The preparation and structural characterization of a family of viscoelastic dispersions of borate cross-linked, 80% hydrolyzed poly(vinyl acetate) (80PVAc) in aqueous-organic liquids are presented. Correlations between mechanical properties (from rheological measurements) and the degree and nature of cross-linking (from (11)B NMR spectroscopy) are reported, and the results are used to assess their potential as low-impact cleaning agents for the surfaces of paintings. Because the dispersions can be prepared at room temperature by simple procedures from readily available materials and can contain up to 50% (w/w) of an organic liquid, they offer important advantages over previously described cleaning agents that are based on fully hydrolyzed PVAc (i.e., poly(vinyl alcohol). The mechanical properties of the various aqueous-organic dispersions, as determined quantitatively by rheological investigations and qualitatively by their ease of removal from a solid surface (i.e., the so-called "peel-off" ability) have been tuned systematically by varying the amount of organic liquid, its structure, and the concentrations of borax and 80PVAc. The (11)B NMR studies demonstrate that the concentration of borate ions actively participating in cross-linking increases significantly with the amount of organic liquid in the mixture. The degree of cross-linking remains constant when the 80PVAc and borax concentrations are varied, as long as their ratios are kept constant. Some of the 80PVAc-borax dispersions have been tested successfully as cleaning agents on the surface of a 16th-17th century oil-on-wood painting by Lodovico Cardi, "Il Cigoli", that was covered by a brown patina and on the surface of a Renaissance wall painting by Vecchietta in Santa Maria della Scala, Siena, Italy, that had a degraded polyacrylate coating from a previous conservation treatment. PMID:21749078

Natali, Irene; Carretti, Emiliano; Angelova, Lora; Baglioni, Piero; Weiss, Richard G; Dei, Luigi

2011-11-01

11

A novel simple one-step air jet spinning approach for deposition of poly(vinyl acetate)/hydroxyapatite composite nanofibers on Ti implants.  

PubMed

A biocompatible coating consists of a poly(vinyl acetate)/hydroxyapatite (PVAc/HA) composite nanofiber mat was applied to NaOH-treated titanium metal by means of a novel, facile and efficient air jet spinning (AJS) approach. Results showed that HA nanoparticles (NPs) strongly embedded onto the AJS single fiber surface resulting in a strong chemical interfacial bonding between the two phases due to the difference in kinetic energies. It was proven that AJS membrane coatings can provide significant improvement in the corrosion resistance of titanium substrate. Interestingly, the biocompatibility using MC3T3-E1 osteoblast to the PVAc/HA fiber composite layer coated on Ti was significantly higher than pure titanium-substrates. PMID:25686997

Abdal-Hay, Abdalla; Hamdy, Abdel Salam; Khalil, Khalil Abdelrazek; Lim, Ju Hyun

2015-04-01

12

Novel Poly(vinyl alcohol)\\/Clay Nanocomposite Microspheres via Suspension Polymerization and Saponification  

Microsoft Academic Search

Poly(vinyl alcohol) (PVA)\\/montmorillonite (MMT) clay nanocomposite microspheres were synthesized through suspension polymerization followed by the heterogeneous saponification for the first time. The effects of MMT on the saponification rate of poly(vinyl acetate) (PVAc) microspheres were studied. It was found that the saponification rate of PVAc significantly increased in the presence of MMT particles. The molecular weight of extracted PVA from

Jeong Hyun Yeum

2011-01-01

13

Physicochemical characterization of partially hydrolyzed poly(vinyl acetate)-borate aqueous dispersions.  

PubMed

The dynamic and structural properties of Highly Viscous Polymeric Dispersions (HVPDs), constituted of polyvinyl alcohol obtained from the 75% hydrolysis (75PVA) of polyvinlyl acetate (PVAc) cross-linked with borate ions, were studied as a function of the 75PVA concentration at a constant ratio between the OH groups and the borate ions (OH/B(OH)4(-)). The threshold 75PVA concentration C* necessary for the formation of the three-dimensional network was determined by flow rheology. The oscillating rheology measurements were performed in the linear viscoelastic region; the relaxation spectra calculated from the frequency sweep curves showed only one peak whose width increased upon increasing the 75PVA concentration due to the broadening of the relaxation modes. The dependence of the mean relaxation time ?H upon the concentration of 75PVA followed a power law expression (?H ? C(x) with x = 1.9) indicating that ?H referred to a sticky reptation mechanism and that water was a good solvent for 75PVA as confirmed also by small angle X-rays scattering (SAXS) investigation. The HVPDs were used for the removal of grime layers from the surface of Carlo Carrà (1881-1966) paints decorating the walls of the Palazzo di Giustizia in Milan, Italy. PMID:24818671

Carretti, E; Matarrese, C; Fratini, E; Baglioni, P; Dei, L

2014-07-01

14

Composite poly(vinyl alcohol)/poly(vinyl acetate) electrospun nanofibrous mats as a novel wound dressing matrix for controlled release of drugs  

PubMed Central

The aim of this study was to develop novel biomedicated nanofiber electrospun mats for controlled drug release, especially drug release directly to an injury site to accelerate wound healing. Nanofibers of poly(vinyl alcohol) (PVA), poly(vinyl acetate) (PVAc), and a 50:50 composite blend, loaded with ciprofloxacin HCl (CipHCl), were successfully prepared by an electrospinning technique for the first time. The morphology and average diameter of the electrospun nanofibers were investigated by scanning electron microscopy. X-ray diffraction studies indicated an amorphous distribution of the drug inside the nanofiber blend. Introducing the drug into polymeric solutions significantly decreased solution viscosities as well as nanofiber diameter. In vitro drug release evaluations showed that both the kind of polymer and the amount of drug loaded greatly affected the degree of swelling, weight loss, and initial burst and rate of drug release. Blending PVA and PVAc exhibited a useful and convenient method for electrospinning in order to control the rate and period of drug release in wound healing applications. Also, the thickness of the blend nanofiber mats strongly influenced the initial release and rate of drug release. PMID:21720511

Jannesari, Marziyeh; Varshosaz, Jaleh; Morshed, Mohammad; Zamani, Maedeh

2011-01-01

15

Effects of adding nano-clay on performance of polyvinyl acetate (PVA) as a wood adhesive  

Microsoft Academic Search

Polyvinyl acetate (PVA), a thermoplastic polymer, has poor performance at elevated temperatures and humid conditions as a wood adhesive. Two types of hydrophilic nano-clay were mixed at different loadings (1%, 2% and 4%) with PVA to improve the performance of PVA towards water and elevated temperatures. The properties of PVA-clay nanocomposites were characterized by measuring the shear strength of wood

Alireza Kaboorani; Bernard Riedl

2011-01-01

16

Poly(vinyl chloride) polyacrylonitrile composite membranes for the dehydration of acetic acid  

Microsoft Academic Search

Composite membranes have been prepared consisting of a poly(vinyl chloride) (PVC) top layer on either a dense polyacrylonitrile (PAN) layer (bi-layer membrane) or a porous PAN support layer (normal composite membrane) and studied with respect to the dehydration of acetic acid. Especially, the influence of the surface porosity of the porous support layer on the selectivity and flux was studied

G. H. Koops; J. A. M. Nolten-Oude Hendrikman; M. H. V. Mulder; C. A. Smolders

1993-01-01

17

Li ion conducting gel polymer electrolytes based on Poly(vinyl acetate)  

NASA Astrophysics Data System (ADS)

A novel gel polymer electrolyte based on poly(vinyl acetate) and poly(vinylidene fluoride) with different plasticizers was prepared and studied by X-ray diffraction and Ac impedance methods. The blend polymer electrolyte containing propylene carbonate (PC) exhibits the highest conductivity 0.922 × 10-2 Scm-1 at room temperature and the results were discussed.

Rajendran, S.; Mathew, Chithra M.; Marimuthu, T.; Kesavan, K.

2013-06-01

18

Effect of poly(vinyl alcohol-co-vinyl acetate) copolymer blockiness on the dynamic interfacial tension and dilational viscoelasticity of polymer-anionic surfactant complex at the water-1-chlorobutane interface.  

PubMed

Poly(vinyl alcohol-co-vinyl acetate) (PVA) copolymers obtained by partial hydrolysis of poly(vinyl acetate) (PVAc) are of practical importance for many applications, including emulsion and suspension polymerization processes. Their molecular characteristics have a major influence on the colloidal and interfacial properties. The most significant characteristics are represented by the average degree of hydrolysis , average degree of polymerization but also by the average acetate sequence length n which designates the so-called blockiness. Colloidal aggregates were observed in the aqueous PVA solutions having a value of 73 mol%. The volume fraction of these aggregates at a given value is directly correlated to the blockiness. Three PVA samples with identical and but different blockiness were examined. By pendant drop and oscillating pendant drop techniques it was shown that the PVA sample having the lowest blockiness and thus the lowest volume fraction of colloidal aggregates has lower interfacial tension and elastic modulus E' values. On the contrary, the corresponding values are highest for PVA sample of higher blockiness. In the presence of sodium dodecyl sulfate (SDS), the colloidal aggregates are disaggregated by complex formation due to the hydrophobic-hydrophobic interactions. The PVA-SDS complex acts as a partial polyelectrolyte that induces the stretching of the chains and thus a reduction of the interface thickness. In this case, the interfacial tension and the elastic modulus both increase with increasing SDS concentration for all three PVA samples and the most significant effect was noticed for the most "blocky" copolymer sample. PMID:25691435

Atanase, Leonard Ionut; Bistac, Sophie; Riess, Gérard

2015-03-18

19

Modulated differential scanning calorimetry: 8. Interface development between films of polyepichlorohydrin and poly(vinyl acetate)  

Microsoft Academic Search

A thermal method with the potential to determine the weight fraction and the interfacial thickness in multiphase polymer materials is described. The extent of interdiffusion, and hence the development of an interface between two miscible polymers, polyepichlorohydrin and poly(vinyl acetate), with time at 100°C has been studied by means of modulated-temperature differential scanning calorimetry. This polymer pair is known to

M. Reading

1997-01-01

20

Preparation of poly(vinyl alcohol)/kaolinite nanocomposites via in situ polymerization  

SciTech Connect

Poly(vinyl alcohol)/kaolinite intercalated nanocomposites (Kao-PVA) were prepared via in situ intercalation radical polymerization. Vinyl acetate (VAc) was intercalated into kaolinite by a displacement method using dimethyl sulfoxide/kaolinite (Kao-DMSO) as the intermediate. Then, PVAc/kaolinite (Kao-PVAc) was obtained via radical polymerization with benzoyl peroxide (BPO) as initiator. Last, PVAc/kaolinite was saponified via direct-hydrolysis with NaOH solution in order to obtain PVA/kaolinite nanocomposites, which was characterized by Fourier-Transformation spectroscopy (FTIR), wide X-ray diffraction (WXRD) and transmission electron microscopy (TEM). Their differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) results of the obtained PVA/kaolinite suggested that the thermal properties had an obvious improvement.

Jia Xin [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology, Lanzhou University, Lanzhou 730000 (China); Department of Chemistry, Hexi University, Zhangye 734000 (China); Li Yanfeng [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology, Lanzhou University, Lanzhou 730000 (China)], E-mail: liyf@lzu.edu.cn; Zhang Bo; Cheng Qiong; Zhang Shujiang [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology, Lanzhou University, Lanzhou 730000 (China)

2008-03-04

21

Influence of hydrophobe on the release behavior of vinyl acetate miniemulsion polymerization.  

PubMed

Poly(vinyl acetate) (PVAc) nanoparticles containing antibiotic have been prepared by miniemulsion polymerization. To compare the effect of hydrophobe types, hexadecane and poly(vinyl acetate) were used as hydrophobe. The particle characteristics as the manufacturing condition were examined by particle size analyzer. As a result, the diameter of PVAc latexes was adjusted between 80 and 260 nm by homogenization conditions and amounts of surfactant. Also, the miniemulsion by using hexadecane showed the more long shelf stability and led to the more small particle size after polymerization, as compared with the case of using poly(vinyl acetate). This indicated that the use of poly(vinyl acetate) as a hydrophobe could not make the stable emulsion, but it could avoid volatile organic chemical problems in the final product. From the release profile of drug through UV spectra, the drug release was very slow and it could be seen that the release of drug encapsulated with PVAc was occurred with the polymer degradation. PMID:16214307

Park, Soo-Jin; Kim, Ki-Seok

2005-11-25

22

Biomedical applications of stereoregular poly(vinyl alcohol) micro- and nanoparticles  

NASA Astrophysics Data System (ADS)

Syndiotactic poly(vinyl alcohol) (PVA)/poly(vinyl pivalate/vinyl acetate) (P(VPi/VAc)) and atactic PVA/PVAc micro- and nanoparticles with skin/core structure have been prepared by heterogeneous saponification of P(VPi/VAc) and PVAc micro- and nanoparticles. Especially, to prepare P(VPi/VAc) and PVAc microparticles having various particle sizes and uniform particle size distribution, vinyl pivalate (VPi)/vinyl acetate (VAc) and VAc were suspension-polymerized using a low-temperature initiator, 2,2"-azobis(2,4-dimethylvaleronitrile). P(VPi/VAc) particles are promising precursor of stereoregular PVA embolic materials which can be introduced through catheters in the management of gastrointestinal bleeders, arteriovenous malformations, hemangiomas, and traumatic rupture of blood vessels. Monodisperse and/or nearly monodisperse P(VPi/VAc) and PVAc microparticles with various particle diameters were obtained by controlling suspension polymerization conditions. Monodisperse P(VPi/VAc) and PVAc microparticles having various particle sizes were partially saponified in the heterogeneous system. PVA/P(VPi/VAc) and PVA/PVAc microparticles having various tacticity and degree of saponification were produced by controlling various polymerization and saponification conditions. The coating of stereoregular PVA micro- and nanoparticles for drug release experiments was conducted with the strepo-avidin-alkaline phosphatase conjugate in variable conditions of pH value, coating buffer, and reaction temperature. Protein-coated syndiotactic PVA micro- and nanoparticles, which does not crosslinking, were more superior to controllability of drug release, durability, and dimensional stability to water and blood than atactic one.

Lyoo, Won Seok; Kim, Joon Ho; Kim, Sam Soo; Ghim, Han Do

2002-11-01

23

Enhancement of service characteristics of boon boards by modifying carbamide-formaldehyde binder with poly(vinyl acetate) dispersion  

Microsoft Academic Search

Carbamide-formaldehyde oligomer is modified with poly(vinyl acetate) dispersion taking into account the basic notions of the\\u000a theory of adhesive wetting. It is established that this type of modification makes it possible to enhance the adhesive properties\\u000a of carbamide-formaldehyde oligomer to the flax boon and to improve the qualitative characteristics of boon boards. The optimal\\u000a amount of modifier is determined. Results

S. A. Ugryumov; V. E. Tsvetkov

2008-01-01

24

Preparation and study of poly(vinyl acetate) and poly(styrene) nanosized latex with indometacin.  

PubMed

During the last decade the number of investigations on the preparation and application of more effective drug release systems on the basis of nanocarriers from biocompatible and biodegradable polymers are considerably increasing. This is notably in force for practically water insoluble drugs to be applied in liquid forms (eye solutions for an example). The aim of the work presented was the preparation of model poly(vinyl acetate) and poly(styrene) nanosupports for indometacin and their potential inclusion in eye drops. The polymers are synthesized as nanosized latex by a radical polymerization of the monomers in the presence of indometacin. It is proved that the low polymerization temperature and initiator used do not influence indometacin structure and properties. The nanoparticles were characterized by attenuated total reflection Fourier transform infrared spectroscopic analyses, atomic force microscopy, scanning electron microscopy and transmission electron microscopy. The size of the latex particles was around 200 nm, determined by the scan electron microscopy. The indometacin delivery rate from the supports discussed in aqueous solutions was determined at pH 7.4. The change of this rate, in comparison with that for a pure drug substance, was established also as well as its dependence on the nature of the carrier. PMID:22888516

Andonova, V; Georgiev, G; Toncheva, V; Kassarova, M

2012-07-01

25

Controlled Release of Retinyl Acetate from ?-Cyclodextrin Functionalized Poly(vinyl alcohol) Electrospun Nanofibers.  

PubMed

Retinyl acetate (RA) was effectively incorporated into electrospun nanofibers of poly(vinyl alcohol) (PVA) containing ?-cyclodextrin (?-CD) in order to form inclusion complexes for encapsulation to prolong shelf life and thermal stability. The physical and thermal properties of encapsulated RA were determined by scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). The nanofibers of PVA/RA and PVA/RA/?-CD exhibited bead free average fiber diameters of 264 ± 61 and 223 ± 49 nm, respectively. The surface chemistry of the functional nanofibers was investigated by X-ray photoelectron spectroscopy (XPS). Thermogravimetric analysis (TGA) demonstrated different thermal stabilities between the bioactive and the polymer, with and without ?-CD. Square-wave voltammogram peak current changes were used to follow the release kinetics of RA from the nanofibers. Results indicate that RA coated inside PVA/?-CD nanofibers was protected against oxidation much better than RA in PVA nanofibers and should extend the shelf life. In addition, RA encapsulated in the PVA/?-CD had better thermal stability than PVA nanofibers. PMID:25779354

Lemma, Solomon M; Scampicchio, Matteo; Mahon, Peter J; Sbarski, Igor; Wang, James; Kingshott, Peter

2015-04-01

26

Poly(vinyl chloride) blend with biodegradable cellulose acetate in presence of N-(phenyl amino) maleimides.  

PubMed

Wider plastic applications of poly(vinyl chloride) (PVC) has raised serious problem to the environment. Since (PVC) waste products resist biodegradation and persist in the environment for longer time. The object of this study is to blend (PVC) with biodegradable cellulose acetate to thermally support the polymer during the molding process as well as to enhance the biodegradability of (PVC) waste products. Blending of poly(vinyl chloride) and cellulose acetate (CA) in presence of N-(phenyl amino) maleimides (R-PhAM) where (R=H, 4-NO2) led to improvement in the thermal stability of the blend film at high temperatures as shown from the high values of initial decomposition temperature (To) determined from their thermogravimetry (TG) curves. Also, blending (PVC) with (CA) led to improvement in the mechanical properties of the blend films as compared to (PVC). The crystalline regions of cellulose acetate enhanced the elasticity of the blend films as shown from their high Young's modulus values. PMID:24973650

Abdel-Naby, Abir S; Al-Ghamdi, Azza A

2014-09-01

27

Space resolved relaxation dynamics of poly(vinyl acetate) close to interfaces with SiOx nanoinclusions  

NASA Astrophysics Data System (ADS)

The influence on relaxation dynamics of poly(vinyl acetate) of SiOx nanoparticles dispersed in the polymeric matrix was investigated by Local Dielectric Spectroscopy, measuring the phase loss angle in the polymer as a function of the distance from the nanoparticles. Both images of phase loss angle and acquisition of local dielectric spectra show two distinct features, namely, a faster relaxation dynamics when approaching the nanoparticle surface, and a rather large range of influence on polymer dynamics with respect to nanoparticle size, probe size, and gyration radius of the polymer.

Labardi, M.; Prevosto, D.; Nguyen, H. K.; Lucchesi, M.; Fanizza, E.; Depalo, N.; Striccoli, M.

2012-07-01

28

Determination of the plasticizer content in poly(vinyl acetate) paint medium by pyrolysis–silylation–gas chromatography–mass spectrometry  

Microsoft Academic Search

The use of plasticizers in emulsion paints is intended to provide optimal mechanical properties to polyvinyl acetate polymers (PVA), making them suitable as binding media for paintings. The loss of these properties with ageing is often related to the slow migration and evaporation of such plasticizers, resulting in severe embrittlement and potential damage to the paint film.A new method consisting

Miguel F. Silva; Maria Teresa Doménech-Carbó; Laura Fuster-Lopéz; Susana Martín-Rey; Marion F. Mecklenburg

2009-01-01

29

Determination of the plasticizer content in poly(vinyl acetate) paint medium by pyrolysis-silylation-gas chromatography-mass spectrometry  

Microsoft Academic Search

The use of plasticizers in emulsion paints is intended to provide optimal mechanical properties to polyvinyl acetate polymers (PVA), making them suitable as binding media for paintings. The loss of these properties with ageing is often related to the slow migration and evaporation of such plasticizers, resulting in severe embrittlement and potential damage to the paint film. A new method

Miguel F. Silva; Maria Teresa Domenech-Carboa; Laura Fuster-Lopez; Susana Martin-Rey; Marion F. Mecklenburg

30

Polyvinyl Alcohol Hydrogel Irradiated and Acetalized for Osteochondral Defect Repair: Mechanical, Chemical, and Histological Evaluation after Implantation in Rat Knees  

PubMed Central

Polyvinyl Alcohol (PVA) hydrogel plugs were implanted in artificial osteochondral defects on the trochlear groove of rat knees. After 0, 3, 6, 12, and 24 weeks of followup, samples containing the implants were mechanically evaluated by creep indentation test, chemically, and histologically by optical microscopy. The mechanical test pointed towards an increase of the implant creep modulus and the chemical analysis exhibited an increasing concentration of calcium and phosphorus within the implants over time. Optical microscopy showed no foreign body reaction and revealed formation, differentiation, and maintenance of new tissue at the defect/implant interface. The absence of implant wear indicated that the natural articular lubrication process was not disturbed by the implant. The performance of the irradiated and acetalized PVA was considered satisfactory for the proposed application. PMID:23197982

Batista, N. A.; Rodrigues, A. A.; Bavaresco, V. P.; Mariolani, J. R. L.; Belangero, W. D.

2012-01-01

31

Modifying theophylline microparticle surfaces via the sequential deposition of poly(vinyl alcohol-co-vinyl acetate) copolymers.  

PubMed

The aim of this study was to investigate the manner in which amphiphilic poly(vinyl alcohol-co-vinyl acetate) copolymers (PVA-Ac) assembled on drug surfaces and use this information to generate a novel bi-layer polymer coating for a theophylline microparticle. Three grades of PVA-Ac, differing in hydrolysis degree and monomer distribution, were synthesised, characterised by nuclear magnetic resonance and shown to interact with theophylline when suspended in water. PVA-Ac deposition at the solid/liquid interface was driven by polymer hydrogen bond formation in a process that induced consequential structural changes in the macromolecule architecture. The most hydrophobic grades of the copolymer appeared to adsorb in a multistage process that passed through a series of equilibrium points. The PVA-Ac surface allowed two grades of the copolymer to be sequentially adsorbed and this resulted in the fabrication of a microparticle with desirable characteristics for pharmaceutical formulation production. PMID:24355619

Zhao, Yanjun; Alas'ad, Mannar A; Jones, Stuart A

2014-03-10

32

Nonwoven mats of poly(vinyl alcohol)\\/chitosan blends containing silver nanoparticles: Fabrication and characterization  

Microsoft Academic Search

Non-woven mats of a poly(vinyl alcohol) (PVA)\\/chitosan (CS) blend (PVA\\/CS) and PVA\\/CS blends incorporated with silver (Ag) nanoparticles (Ag\\/PVA\\/CS) were fabricated by an electrospinning method. The electrospun fibers attained a beaded structure at PVA to CS weight ratios of up to 88\\/12. The addition of AgNO3 to the PVA\\/CS blend solution improved the electrospinnability. The morphology of the electrospun non-woven

Au Thi Hang; Beomseok Tae; Jun Seo Park

2010-01-01

33

Aspects of the performance of PVAc adhesives in wood joints  

Microsoft Academic Search

Various modifications of polyvinyl acetate emulsion wood adhesive were made and their performance evaluated in standard tests. The results are interpreted in the context of adhesion theories and the chemical structures of the polymers and wood. The adhesion of the polymers to wood and the cohesive strength of the polymers are the two predominant factors determining the performance of the

Lijun Qiao; Allan J. Easteal

2001-01-01

34

Coating gigaporous polystyrene microspheres with cross-linked poly(vinyl alcohol) hydrogel as a rapid protein chromatography matrix.  

PubMed

Gigaporous polystyrene (PS) microspheres were hydrophilized by in situ polymerization to give a stable cross-linked poly(vinyl alcohol) (PVA) hydrogel coating, which can shield proteins from the hydrophobic PS surface underneath. The amination of microspheres (PS-NH2) was first carried out through acetylization, oximation and reduction, and then 4,4'-azobis (4-cyanovaleric acid) (ACV), a polymerization initiator, was covalently immobilized on PS-NH2 through amide bond formation, and the cross-linked poly(vinyl acetate) (PVAc) was prepared by radical polymerization at the surfaces of ACV-immobilized PS microspheres (PS-ACV). Finally, the cross-linked PVA hydrogel coated gigaporous PS microspheres (PS-PVA) was easily achieved through alcoholysis of PVAc. Results suggested that the PS microspheres were effectively coated with cross-linked PVA hydrogel, where the gigaporrous structure remained under optimal conditions. After hydrophilic modification (PS-PVA), the protein-resistant ability of microspheres was greatly improved. The hydroxyl-rich PS-PVA surface can be easily derivatized by classical chemical methods. Performance advantages of the PS-PVA column in flow experiment include good permeability, low backpressure, and mechanical stability. These results indicated that PS-PVA should be promising in rapid protein chromatography. PMID:25017479

Qu, Jian-Bo; Huan, Guan-Sheng; Chen, Yan-Li; Zhou, Wei-Qing; Liu, Jian-Guo; Huang, Fang

2014-08-13

35

Anion recognition using newly synthesized hydrogen bonding disubstituted phenylhydrazone-based receptors: poly(vinyl chloride)-based sensor for acetate.  

PubMed

A potentiometric acetate-selective sensor, based on the use of butane-2,3-dione,bis[(2,4-dinitrophenyl)hydrazone] (BDH) as a neutral carrier in poly(vinyl chloride) (PVC) matrix, is reported. Effect of various plasticizers and cation excluder, cetryaltrimethylammonium bromide (CTAB) was studied. The best performance was obtained with a membrane composition of PVC:BDH:CTAB ratio (w/w; mg) of 160:8:8. The sensor exhibits significantly enhanced selectivity toward acetate ions over a wide concentration range 5.0 x 10(-6) to 1.0 x 10(-1)M with a lower detection limit of 1.2 x 10(-6)M within pH range 6.5-7.5 with a response time of <15s and a Nernstian slope of 60.3+/-0.3 mV decade(-1) of activity. Influences of the membrane composition, and possible interfering anions were investigated on the response properties of the electrode. Fast and stable response, good reproducibility and long-term stability are demonstrated. The sensor has a response time of 15s and can be used for at least 65 days without any considerable divergence in their potential response. Selectivity coefficients determined with the separate solution method (SSM) and fixed interference method (FIM) indicate that high selectivity for acetate ion. The proposed electrode shows fairly good discrimination of acetate from several inorganic and organic anions. It was successfully applied to direct determination of acetate within food preservatives. Total concentration of acetic acid in vinegar samples were determined by direct potentiometry and the values agreed with those mentioned by the manufacturers. PMID:18656670

Gupta, Vinod K; Goyal, Rajendra N; Sharma, Ram A

2008-08-15

36

Preparation and characterization of poly(vinyl chloride-co-vinyl acetate)-based gel electrolytes for Li-ion batteries  

SciTech Connect

Poly(vinyl chloride) (PVC)-based electrolytes, a class of the most promising polymer electrolytes, are found to suffer from solvent exudation. Two strategies were employed to suppress this shortcoming, one involving the replacement of PVC with poly(vinyl chloride-co-vinyl acetate) (PVCAC) copolymer and the other the direct utilization of solvents for PVC or PVCAC instead of using an auxiliary carrier solvent (e.g., tetrahydrofuran, THF). The thermodynamics of polymer solubility was particularly emphasized in the latter approach. N,N-dimethylformamide (DMF) and N-methyl pyrrolidionone (NMP) are preferred cosolvents of ethylene carbonate (EC) and/or propylene carbonate (PC). The PVCAC-based gel electrolytes prepared were then characterized by ionic conductivity, cyclic voltammetry, and ac impedance data. The results indicate that electrolytes containing NMP/EC mixed solvent exhibit conductivities exceeding 10{sup {minus}3} S/cm whereas the electrolytes containing DMF/EC/PC exhibit conductivities around 10{sup {minus}4} S/cm at room temperature. Moreover, the former category was found to be oxidatively stable up to 4.9 V vs. Li/Li{sup +} and the latter to 4.6 V vs. Li/Li{sup +}. Finally, ac impedance results suggest that the stability of the Li/electrolyte interface needs further improvement, which is a crucial task for most polymer gel electrolytes at present.

Sung, H.Y.; Wang, Y.Y.; Wan, C.C. [National Tsing-Hua Univ., Hsinchu (Taiwan, Province of China). Dept. of Chemical Engineering

1998-04-01

37

Response to ``Comment on `Temperature divergence of the dynamics of a poly(vinyl acetate) glass: Dielectric vs. mechanical behaviors''' [J. Chem. Phys. 139, 137101 (2013)  

NASA Astrophysics Data System (ADS)

R. Richert has made a comment to a paper of ours in which dielectric measures on poly(vinyl acetate) suggest that there is a change in temperature dependence of the temperature shift factors from Vogel-Fulcher-Tammann (VFT) to Arrhenius near to the glass transition temperature. He notes that we made an error in the description of his data and further notes that the data we did not use show a VFT behavior to well below the glass transition. Here we respond to the comment and add additional analysis that suggest that the differences in results are related to the differences between time temperature superposition (TTS) of data and fitting the data with a Kohlrausch, Williams, and Watts function. When TTS is used on the data from Wagner and Richert [Polymer 38, 255 (1997)] the change in behavior to Arrhenius-like below Tg is recovered.

Zhao, Jing; McKenna, Gregory B.

2013-10-01

38

Comment on ``Temperature divergence of the dynamics of a poly(vinyl acetate) glass: Dielectric vs. mechanical behaviors'' [J. Chem. Phys. 136, 154901 (2012)  

NASA Astrophysics Data System (ADS)

The temperature dependence of polymer dynamics below the standard glass transition is of considerable interest. Glassy relaxation dictates the process of physical aging, and understanding these slow dynamics helps in assessing a possible divergence at a finite temperature. In a recent paper, Zhao and McKenna have measured the equilibrium dynamics of poly(vinyl acetate) in the range from Tg - 15 K to Tg + 30 K using Struiks protocol [J. Zhao and G. B. McKenna, J. Chem. Phys. 136, 154901 (2012)]. In a figure that is meant to compare their results with dielectric relaxation data from Wagner and Richert [Polymer 38, 255 (1997)], dielectric retardation data from that work is shown instead. The corrected figure shows a considerable difference in the two measurements below Tg - 10 K, Arrhenius versus Vogel-Fulcher-Tammann behavior, and a possible source of the difference is discussed.

Richert, Ranko

2013-10-01

39

New insights on poly(vinyl acetate)-based coated floating tablets: Characterisation of hydration and CO 2 generation by benchtop MRI and its relation to drug release and floating strength  

Microsoft Academic Search

The purpose of this study was to investigate the mechanism of floating and drug release behaviour of poly(vinyl acetate)-based floating tablets with membrane controlled drug delivery. Propranolol HCl containing tablets with Kollidon® SR as an excipient for direct compression and different Kollicoat® SR 30 D\\/Kollicoat® IR coats varying from 10 to 20mg polymer\\/cm2 were investigated regarding drug release in 0.1N

Sandra Strübing; Tâmara Abboud; Renata Vidor Contri; Hendrik Metz; Karsten Mäder

2008-01-01

40

Estimation of polyvinyl alcohol cryogel mechanical properties with four ultrasound elastography methods and comparison with gold standard testings  

Microsoft Academic Search

Tissue-mimicking phantoms are very useful in the field of tissue characterization and essential in elastography for the purpose of validating motion estimators. This study is dedicated to the characterization of polyvinyl alcohol cryogel (PVA-C) for these types of applications. A strict fabrication procedure was defined to optimize the reproducibility of phantoms having a similar elasticity. Following mechanical stretching tests, the

Jeremie Fromageau; Jean-Luc Gennisson; Cedric Schmitt; Roch L. Maurice; Rosaire Mongrain; G. Cloutier

2007-01-01

41

Cellulose Nanocrystals/ZnO as a Bifunctional Reinforcing Nanocomposite for Poly(vinyl alcohol)/Chitosan Blend Films: Fabrication, Characterization and Properties  

PubMed Central

In this study, cellulose nanocrystals/zinc oxide (CNCs/ZnO) nanocomposites were dispersed as bifunctional nano-sized fillers into poly(vinyl alcohol) (PVA) and chitosan (Cs) blend by a solvent casting method to prepare PVA/Cs/CNCs/ZnO bio-nanocomposites films. The morphology, thermal, mechanical and UV-vis absorption properties, as well antimicrobial effects of the bio-nanocomposite films were investigated. It demonstrated that CNCs/ZnO were compatible with PVA/Cs and dispersed homogeneously in the polymer blend matrix. CNCs/ZnO improved tensile strength and modulus of PVA/Cs significantly. Tensile strength and modulus of bio-nanocomposite films increased from 55.0 to 153.2 MPa and from 395 to 932 MPa, respectively with increasing nano-sized filler amount from 0 to 5.0 wt %. The thermal stability of PVA/Cs was also enhanced at 1.0 wt % CNCs/ZnO loading. UV light can be efficiently absorbed by incorporating ZnO nanoparticles into a PVA/Cs matrix, signifying that these bio-nanocomposite films show good UV-shielding effects. Moreover, the biocomposites films showed antibacterial activity toward the bacterial species Salmonella choleraesuis and Staphylococcus aureus. The improved physical properties obtained by incorporating CNCs/ZnO can be useful in variety uses. PMID:24945313

Azizi, Susan; Ahmad, Mansor B.; Ibrahim, Nor Azowa; Hussein, Mohd Zobir; Namvar, Farideh

2014-01-01

42

Cellulose nanocrystals/ZnO as a bifunctional reinforcing nanocomposite for poly(vinyl alcohol)/chitosan blend films: fabrication, characterization and properties.  

PubMed

In this study, cellulose nanocrystals/zinc oxide (CNCs/ZnO) nanocomposites were dispersed as bifunctional nano-sized fillers into poly(vinyl alcohol) (PVA) and chitosan (Cs) blend by a solvent casting method to prepare PVA/Cs/CNCs/ZnO bio-nanocomposites films. The morphology, thermal, mechanical and UV-vis absorption properties, as well antimicrobial effects of the bio-nanocomposite films were investigated. It demonstrated that CNCs/ZnO were compatible with PVA/Cs and dispersed homogeneously in the polymer blend matrix. CNCs/ZnO improved tensile strength and modulus of PVA/Cs significantly. Tensile strength and modulus of bio-nanocomposite films increased from 55.0 to 153.2 MPa and from 395 to 932 MPa, respectively with increasing nano-sized filler amount from 0 to 5.0 wt %. The thermal stability of PVA/Cs was also enhanced at 1.0 wt % CNCs/ZnO loading. UV light can be efficiently absorbed by incorporating ZnO nanoparticles into a PVA/Cs matrix, signifying that these bio-nanocomposite films show good UV-shielding effects. Moreover, the biocomposites films showed antibacterial activity toward the bacterial species Salmonella choleraesuis and Staphylococcus aureus. The improved physical properties obtained by incorporating CNCs/ZnO can be useful in variety uses. PMID:24945313

Azizi, Susan; Ahmad, Mansor B; Ibrahim, Nor Azowa; Hussein, Mohd Zobir; Namvar, Farideh

2014-01-01

43

Preparation and properties of poly(vinyl alcohol)/chitosan blend bionanocomposites reinforced with cellulose nanocrystals/ZnO-Ag multifunctional nanosized filler  

PubMed Central

A series of novel bionanocomposites were cast using different contents of zinc oxide-silver nanoparticles (ZnO-AgNPs) stabilized by cellulose nanocrystals (CNC) as multifunctional nanosized fillers in poly(vinyl alcohol)/chitosan (PVA/Cs) matrices. The morphological structure, mechanical properties, ultraviolet-visible absorption, and antimicrobial properties of the prepared films were investigated as a function of their CNC/ZnO-AgNP content and compared with PVA/chitosan/CNC bionanocomposite films. X-ray diffraction and field emission scanning electron microscopic analyses showed that the CNC/ZnO-AgNPs were homogeneously dispersed in the PVA/Cs matrix and the crystallinity increased with increasing nanosized filler content. Compared with pure PVA/Cs, the tensile strength and modulus in the films increased from 0.055 to 0.205 GPa and from 0.395 to 1.20 GPa, respectively. Ultraviolet and visible light can be efficiently absorbed by incorporating ZnO-AgNPs into a PVA/Cs matrix, suggesting that these bionanocomposite films show good visibility and ultraviolet-shielding effects. The bionanocomposite films had excellent antimicrobial properties, killing both Gram-negative Salmonella choleraesuis and Gram-positive Staphylococcus aureus. The enhanced physical properties achieved by incorporating CNC/ZnO-AgNPs could be beneficial in various applications. PMID:24790433

Azizi, Susan; Ahmad, Mansor Bin; Hussein, Mohd Zobir; Ibrahim, Nor Azowa; Namvar, Farideh

2014-01-01

44

Development of the S3Pvac vaccine against murine Taenia crassiceps cysticercosis: a historical review.  

PubMed

Our work of the last 25 yr was concerned with the development of a vaccine aimed to prevent porcine Taenia solium cysticercosis and was based on cross-reacting Taenia crassiceps antigens that had proved protective against experimental intraperitoneal murine T. crassiceps cysticercosis (EIMTcC). In recent times the efficacy of the vaccine has been considered in need of confirmation, and the use of EIMTcC has been questioned as a valid tool in screening for vaccine candidates among the many antigens possibly involved. A review of our work divided in 2 parts is presented at this point, the first dealing with EIMTcC and the second with porcine T. solium cysticercosis (presented in this issue). Herein, we revise our results using EIMTcC as a measure of the protective capacity of T. crassiceps complex antigen mixtures, of purified native antigens, and of S3Pvac anti-cysticercosis vaccine composed by 3 protective peptides: GK-1, KETc1, and KETc12 either synthetic or recombinantly expressed and collectively or separately, by diverse delivery systems when administered at different doses and by different routes. Statistical analyses of the data lead confidently to the strong inference that S3Pvac is indeed an effective vaccine against EIMTcC via specific and non-specific mechanisms of protection. PMID:23409920

Sciutto, Edda; Fragoso, Gladis; Hernández, Marisela; Rosas, Gabriela; Martínez, José J; Fleury, Agnès; Cervantes, Jacquelynne; Aluja, Aline; Larralde, Carlos

2013-08-01

45

In situ self cross-linking of polyvinyl alcohol battery separators  

Microsoft Academic Search

A battery separator was produced from a polyvinyl alcohol sheet structure which was subjected to an in situ, self crosslinking process by selective oxidation of the 1,2 diol units present in the polyvinyl alcohol sheet structure. The 1,2 diol units were cleaved to form aldehyde end groups which subsequently crosslink through acetalization of the 1,3 diol units of the polyvinyl

W. H. Philipp; L. C. Hsu; D. W. Sheibley

1979-01-01

46

Characterization of S3Pvac Anti-Cysticercosis Vaccine Components: Implications for the Development of an Anti-Cestodiasis Vaccine  

PubMed Central

Background Cysticercosis and hydatidosis seriously affect human health and are responsible for considerable economic loss in animal husbandry in non-developed and developed countries. S3Pvac and EG95 are the only field trial-tested vaccine candidates against cysticercosis and hydatidosis, respectively. S3Pvac is composed of three peptides (KETc1, GK1 and KETc12), originally identified in a Taenia crassiceps cDNA library. S3Pvac synthetically and recombinantly expressed is effective against experimentally and naturally acquired cysticercosis. Methodology/Principal Findings In this study, the homologous sequences of two of the S3Pvac peptides, GK1 and KETc1, were identified and further characterized in Taenia crassiceps WFU, Taenia solium, Taenia saginata, Echinococcus granulosus and Echinococcus multilocularis. Comparisons of the nucleotide and amino acid sequences coding for KETc1 and GK1 revealed significant homologies in these species. The predicted secondary structure of GK1 is almost identical between the species, while some differences were observed in the C terminal region of KETc1 according to 3D modeling. A KETc1 variant with a deletion of three C-terminal amino acids protected to the same extent against experimental murine cysticercosis as the entire peptide. On the contrary, immunization with the truncated GK1 failed to induce protection. Immunolocalization studies revealed the non stage-specificity of the two S3Pvac epitopes and their persistence in the larval tegument of all species and in Taenia adult tapeworms. Conclusions/Significance These results indicate that GK1 and KETc1 may be considered candidates to be included in the formulation of a multivalent and multistage vaccine against these cestodiases because of their enhancing effects on other available vaccine candidates. PMID:20585656

Rassy, Dunia; Bobes, Raúl J.; Rosas, Gabriela; Anaya, Victor H.; Brehm, Klaus; Hernández, Beatriz; Cervantes, Jacquelynne; Pedraza, Saúl; Morales, Julio; Villalobos, Nelly; de Aluja, Aline S.; Laclette, Juan P.; Nunes, Caris M.; Biondi, Germano F.; Fragoso, Gladis; Hernández, Marisela; Sciutto, Edda

2010-01-01

47

Fabrication and characterization of cobalt ferrite (CoFe 2O 4) nanofibers by electrospinning  

Microsoft Academic Search

By sol–gel process and electrospinning method, cobalt ferrite\\/polyvinyl acetate (PVAc) composite fiber was obtained. Cobalt ferrite (CoFe2O4) nanofibers were synthesized by calcination of the cobalt ferrite\\/polyvinyl acetate (PVAc) composite fiber with several temperatures. The nanofibers were characterized by SEM, FT-IR, XRD and EXAFS. The diameter of nanofibers was slightly decreased with increasing the calcination temperature. The fibers calcined at 800°C

Young-Wan Ju; Jae-Hyun Park; Hong-Ryun Jung; Sung-June Cho; Wan-Jin Lee

2008-01-01

48

Mercaptobenzothiazole-on-gold organic phase biosensor systems: 1. Enhanced organosphosphate pesticide determination  

Microsoft Academic Search

This paper reports the construction of the gold\\/mercaptobenzothiazole\\/polyaniline\\/acetylcholinesterase\\/polyvinylacetate (Au\\/ MBT\\/PANI\\/AChE\\/PVAc) thick-film biosensor for the determination of certain organophosphate pesticide solutions in selected aqueous organic solvent solutions. The Au\\/MBT\\/PANI\\/AChE\\/PVAc electrocatalytic biosensor device was constructed by encapsulating acetylcholinesterase (AChE) enzyme in the PANI polymer composite, followed by the coating of poly(vinyl acetate) (PVAc) on top to secure the biosensor film from disintegration

V. Somerset; P. Baker; E. Iwuoha

2009-01-01

49

SOURCE ASSESSMENT: POLYVINYL CHLORIDE  

EPA Science Inventory

This report summarizes data on air emissions from the polyvinyl chloride (PVC) industry. PVC is manufactured by 20 companies at 35 plants. Each plant uses one or more of four possible polymerization processes: (1) suspension polymerization, (2) emulsion polymerization, (3) bulk p...

50

Ceramic-supported polymer membranes for pervaporation of binary organic\\/organic mixtures  

Microsoft Academic Search

Asymmetric tubular alumina-supported poly(vinyl acetate) (PVAc) and poly(vinyl pyrrolidone) (PVP) membranes were created and characterized by pervaporation separation of binary mixtures of methanol and methyl tert-butyl ether (MTBE). The active separation layer was created by free-radical graft polymerization of PVAc and PVP onto a vinylsilane-modified alumina substrate with an average native pore diameter of 50Å. The separation layer consisted of

Wayne Yoshida; Yoram Cohen

2003-01-01

51

In situ self cross-linking of polyvinyl alcohol battery separators  

NASA Technical Reports Server (NTRS)

A battery separator was produced from a polyvinyl alcohol sheet structure which was subjected to an in situ, self crosslinking process by selective oxidation of the 1,2 diol units present in the polyvinyl alcohol sheet structure. The 1,2 diol units were cleaved to form aldehyde end groups which subsequently crosslink through acetalization of the 1,3 diol units of the polyvinyl alcohol. Selective oxidation was achieved using a solution of a suitable oxidizing agent such as periodic acid or lead tetraacetate.

Philipp, W. H.; Hsu, L. C.; Sheibley, D. W. (inventors)

1979-01-01

52

Mesoxalaldehyde acetals  

SciTech Connect

The treatment of methylglyoxal acetals by alkyl nitrites in the presence of the corresponding aliphatic alcohols and hydrochloric acid leads to the formation of linear mesoxalaldehyde acetals, whose structure was established by NMR spectroscopy and mass spectrometry. The major pathways for the decomposition of these molecules upon electron impact were established.

Gordeeva, G.N.; Kalashnikov, S.M.; Popov, Yu.N.; Kruglov, E.A.; Imashev, U.B.

1987-11-10

53

Hydroxymethylated resorcinol (HMR) priming agent for improved bondability of wax-treated wood  

Microsoft Academic Search

The effects of hydroxymethylated resorcinol (HMR) on the tensile shear strength of wood joints treated\\u000a with montan ester wax were studied with polyvinyl acetate (PVAc) and melamine formaldehyde (MF) adhesives.\\u000a Untreated specimens which were bonded with MF and PVAc had similar bond strength properties under dry conditions,\\u000a but MF bonded specimens’ tensile shear strength values were higher than that of

R. Kurt; A. Krause; H. Militz; C. Mai

2008-01-01

54

Hydrolysis of ethyl acetate:a pervaporation study  

Microsoft Academic Search

The influence of temperature on the separation factor, diffusion process, permeation rate, and permeability coefficient (k) for hydrolysis of ethyl acetate using a standard poly(vinyl alcohol) (PVA) membrane by pervaporation was investigated. The preliminary data presented in this work was obtained using a simple pervaporation technique built in-house. The experiments were conducted at 80, 65, 50 and 35°C. The initial

Habib I. Shaban

1998-01-01

55

Polyvinyl alcohol battery separator containing inert filler  

Microsoft Academic Search

A cross-linked polyvinyl alcohol battery separator is disclosed. A particulate filler, inert to alkaline electrolyte of an alkaline battery, is incorporated in the separator in an amount of 1-20% by weight, based on the weight of the polyvinyl alcohol, and is dispersed throughout the product. Incorporation of the filler enhances performance and increases cycle life of alkaline batteries when compared

D. W. Sheibley; L. C. Hsu; M. A. Manzo

1981-01-01

56

Polyvinyl alcohol hydrogels for iontohporesis  

NASA Astrophysics Data System (ADS)

Transdermal therapeutic systems propound controlled release of active ingredients through the skin into the systemic circulation in a predictive manner. Drugs administered through these systems escape first-pass metabolism and maintain a steady state scenario similar to a continuous intravenous infusion for up to several days. The iontophoresis deal with the systemic delivery of the bioactive agents (drug) by applying an electric current. It is basically an injection without the needle. The iontophoretic system requires a gel-based matrix to accommodate the bioactive agent. Hydrogels have been used by many investigators in controlled-release drug delivery systems because of their good tissue compatibility and easy manipulation of swelling level and, thereby, solute permeability. In this work we have prepared polyvinyl alcohol (PVA) hydrogel. We have cross linked polyvinyl alcohol chemically with Glutaraldehyde with different wt%. FTIR study reveals the chemical changes during cross linking. Swelling in water, is done to have an idea about drug loading and drug release from the membrane. After drug loading to the hydrogels, we have studied the drug release property of the hydrogels using salicylic acid as a model drug.

Bera, Prasanta; Alam, Asif Ali; Arora, Neha; Tibarewala, Dewaki Nandan; Basak, Piyali

2013-06-01

57

Biocorrosion behavior and cell viability of adhesive polymer coated magnesium based alloys for medical implants  

NASA Astrophysics Data System (ADS)

The present study was ultimately aimed to design novel adhesive biodegradable polymer, poly(vinyl acetate) (PVAc), coatings onto Mg based alloys by the dip-coating technique in order to control the degradation rate and enhance the biocompatibility of magnesium alloys. The influence of various solvents on PVAc surface topography and their protection of Mg alloys were dramatically studied in vitro. Electrochemical polarization, degradation, and PVAc film cytocompatibility were also tested. Our results showed that the solvent had a significant effect on coating quality. PVAc/dichloromethane solution showed a porous structure and solution concentration could control the porous size. The coatings prepared using tetrahydrofuran and dimethylformamide solvents are exceptional in their ability to generate porous morphology even at low polymer concentration. In general, the corrosion performance appears to be different on different PVAc-solvent system. Immersion tests illustrated that the porous morphology on PVAc stabilized corrosion rates. A uniform corrosion attack in artificial simulation body fluid was also exhibited. The cytocompatibility of osteoblast cells (MC3T3) revealed high adherence, proliferation, and survival on the porous structure of PVAc coated Mg alloy, which was not observed for the uncoated samples. This novel PVAc coating is a promising candidate for biodegradable implant materials, which might widen the use of Mg based implants.

Abdal-hay, Abdalla; Dewidar, Montasser; Lim, Jae Kyoo

2012-11-01

58

Three methods for in situ cross-linking of polyvinyl alcohol films for application as ion-conducting membranes in potassium hydroxide electrolyte. [battery separators  

NASA Technical Reports Server (NTRS)

Three methods of in situ cross-linking polyvinyl alcohol films are presented. They are: (1) acetalization with a dialdehyde such as glutaraldehyde, (2) acetalization with aldehyde groups formed by selective oxidative cleaving of the few percent of 1,2 diol units present in polyvinyl alcohol, and (3) cross-linking by hydrogen abstraction by reaction with hydrogen atoms and hydroxyl radicals from irradiated water. For the third method, improvement in film conductivity in KOH solution at the expense of mechanical strength is obtained by the presence of polyacrylic acid in the polyvinyl alcohol films. Resistivities in 45 percent KOH are given for in situ cross-linked films prepared by each of the three methods.

Philipp, W. H.; Hsu, L. C.

1979-01-01

59

Pallidol hexa­acetate ethyl acetate monosolvate  

PubMed Central

The entire mol­ecule of pallidol hexa­acetate {systematic name: (±)-(4bR,5R,9bR,10R)-5,10-bis­[4-(acet­yloxy)phen­yl]-4b,5,9b,10-tetra­hydro­indeno­[2,1-a]indene-1,3,6,8-tetrayl tetra­acetate} is completed by the application of twofold rotational symmetry in the title ethyl acetate solvate, C40H34O12·C4H8O2. The ethyl acetate mol­ecule was highly disordered and was treated with the SQUEEZE routine [Spek (2009 ?). Acta Cryst. D65, 148–155]; the crystallographic data take into account the presence of the solvent. In pallidol hexa­acetate, the dihedral angle between the fused five-membered rings (r.m.s. deviation = 0.100?Å) is 54.73?(6)°, indicating a significant fold in the mol­ecule. Significant twists between residues are also evident as seen in the dihedral angle of 80.70?(5)° between the five-membered ring and the pendent benzene ring to which it is attached. Similarly, the acetate residues are twisted with respect to the benzene ring to which they are attached [C—O(carb­oxy)—C—C torsion angles = ?70.24?(14), ?114.43?(10) and ?72.54?(13)°]. In the crystal, a three-dimensional architecture is sustained by C—H?O inter­actions which encompass channels in which the disordered ethyl acetate mol­ecules reside. PMID:24046702

Mao, Qinyong; Taylor, Dennis K.; Ng, Seik Weng; Tiekink, Edward R. T.

2013-01-01

60

Electrorheology of Polymer Blends Suspended in Silicon Oil  

NASA Astrophysics Data System (ADS)

We studied the electrorheology of amorphous poly(lactic acid) (PLA), poly(vinyl acetate) (PVAc) and poly(ethylene glycol) (PEG) suspensions. For PEG suspensions, the yield stress was observed and increased with the increase in electric field. On the other hand, the PLA and PVAc suspensions did not show ER effect because electrophoresis and discharge between plates occurred. We also studied the ER effect of PLA/PEG and PVAc/PEG blend suspensions. These suspensions snowed the higher yield stress than the neat PEG suspension. It is considered that when the electrophoresis occurs in the weak electric field, the particles migrate to electrode. In general, ER effect is shown in the high electric field. It is considered that high electric field is required to cut this electrophoretic effect for development of striking ER effect. For PLA and PVAc suspensions, it is considered that the electrophoretic effect is too strong and does not show the ER effect.

Hirose, Yuji; Otsubo, Yasufumi

2006-05-01

61

Effect of Renal Embolization with Trisacryl and PAVc  

PubMed Central

OBJECTIVES Evaluate the degree of vascular occlusion, vascular recanalization, and necrosis of the vascular wall caused by polyvinyl alcohol-covered polyvinyl acetate (PVAc) particles compared to trisacryl particles after renal embolization. METHODS Seventy-nine female albino New Zealand rabbits underwent arterial catheterization of the right kidney. Thirty-three animals were embolized with trisacryl particles, thirty-one with PVAc particles, and fifteen were kept as controls. Four animals were excluded (three trisacryl and one PVAc) due to early death. Five subgroups of six animals were created. The animals in the different groups were sacrificed either 48 hours, 5 days, 10 days, 30 days, or 90 days after embolization. The control group was divided into subgroups of three animals each and kept for the same periods of time. The kidneys were dyed with hematoxylin-eosin and Masson’s trichrome and then examined using optical microscopy. RESULTS There were significant differences in the degree of vascular occlusion caused by the trisacryl and the PVAc particles between the five-day and the ten-day groups. Additional differences were noted between the five-day and 48-hour groups in regard to the amount of necrosis. For both findings, the PVAc group members showed adequate tissue reaction (ischemia and volumetric reduction) and less recanalization than those treated with trisacryl. CONCLUSION The use of PVAc as an embolization material exhibited an adequate tissue reaction (ischemia and volumetric reduction), more expressive vascular occlusion and necrosis, and less recanalization than the trisacryl material. PMID:19936185

de Assis Barbosa, Leandro; Caldas, Jose Guilherme Mendes Pereira; Conti, Mario Luiz; Malheiros, Denise Maria Avancini Costa; Ramos, Francisco Ferreira

2009-01-01

62

21 CFR 177.1670 - Polyvinyl alcohol film.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Polyvinyl alcohol film. 177.1670 Section 177.1670 Food and Drugs...Contact Surfaces § 177.1670 Polyvinyl alcohol film. Polyvinyl alcohol film may be safely used in contact with food of...

2014-04-01

63

21 CFR 177.1670 - Polyvinyl alcohol film.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2009-04-01 true Polyvinyl alcohol film. 177.1670 Section 177.1670 Food and Drugs...Contact Surfaces § 177.1670 Polyvinyl alcohol film. Polyvinyl alcohol film may be safely used in contact with food of...

2010-04-01

64

21 CFR 177.1670 - Polyvinyl alcohol film.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Polyvinyl alcohol film. 177.1670 Section 177.1670 Food and Drugs...Contact Surfaces § 177.1670 Polyvinyl alcohol film. Polyvinyl alcohol film may be safely used in contact with food of...

2012-04-01

65

21 CFR 177.1670 - Polyvinyl alcohol film.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Polyvinyl alcohol film. 177.1670 Section 177.1670 Food and Drugs...Contact Surfaces § 177.1670 Polyvinyl alcohol film. Polyvinyl alcohol film may be safely used in contact with food of...

2011-04-01

66

21 CFR 177.1670 - Polyvinyl alcohol film.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Polyvinyl alcohol film. 177.1670 Section 177.1670 Food and Drugs...Contact Surfaces § 177.1670 Polyvinyl alcohol film. Polyvinyl alcohol film may be safely used in contact with food of...

2013-04-01

67

Polyvinyl alcohol battery separator containing inert filler  

NASA Astrophysics Data System (ADS)

A cross-linked polyvinyl alcohol battery separator is disclosed. A particulate filler, inert to alkaline electrolyte of an alkaline battery, is incorporated in the separator in an amount of 1-20% by weight, based on the weight of the polyvinyl alcohol, and is dispersed throughout the product. Incorporation of the filler enhances performance and increases cycle life of alkaline batteries when compared with batteries containing a similar separator not containing filler. Suitable fillers include titanates, silicates, zirconates, aluminates, wood floor, lignin, and titania. Particle size is not greater than about 50 microns.

Sheibley, D. W.; Hsu, L. C.; Manzo, M. A.

1981-06-01

68

Polyvinyl alcohol battery separator containing inert filler  

SciTech Connect

A cross-linked polyvinyl alcohol battery separator is disclosed. A particulate filler, inert to alkaline electrolyte of an alkaline battery, is incorporated in the separator in an amount of 1-20% by weight, based on the weight of the polyvinyl alcohol, and is dispersed throughout the product. Incorporation of the filler enhences performance and increases cycle life of alkaline batteries when compared with batteries containing a similar separator not containing filler. Suitable fillers include titanates, silicates, zirconates, aluminates, wood floor, lignin, and titania. Particle size is not greater than about 50 microns.

Sheibley, D.W.; Hsu, L.C.; Manzo, M.A.

1981-06-01

69

Immunological evaluation of mannosylated chitosan nanoparticles based foot and mouth disease virus DNA vaccine, pVAC FMDV VP1-OmpA in guinea pigs.  

PubMed

A DNA vaccine for foot and mouth disease (FMD) based on mannosylated chitosan nanoparticles was evaluated in guinea pigs. The DNA construct was comprised of FMD virus full length-VP1 gene and outer membrane protein A (Omp A) gene of Salmonella typhimurium as a Toll-like receptor (TLR)-ligand in pVAC vector. Groups of guinea pigs immunized either intramuscularly or intra-nasally were evaluated for induction of virus neutralizing antibodies, Th1(IgG2) and Th2 (IgG1) responses, lymphocyte proliferation, reactive nitrogen intermediate production, secretory IgA for naso-mucosal immune response and protection upon homotypic type O virulent FMD virus challenge. The results indicate the synergistic effect of OmpA on the immunogenic potential of FMD DNA vaccine construct delivered using mannosylated chitosan nano-particles by different routes of administration. These observations suggest the substantial improvement in all the immunological parameters with enhanced protection in guinea pigs. PMID:24656961

Nanda, Raj Kishore; Hajam, Irshad Ahmed; Edao, Bedaso Mammo; Ramya, Kalaivanan; Rajangam, Mageswary; Chandra Sekar, Shanmugam; Ganesh, Kondabattula; Bhanuprakash, Veerakyathappa; Kishore, Subodh

2014-05-01

70

POLY(VINYL ACETATE) AND POLY(VINYL ACETATE-CO-ETHYLENE) LATEXES VIA DISPERSION POLYMERIZATIONS IN CARBON DIOXIDE. (R826115)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

71

Preparation of vinyl acetate  

DOEpatents

This invention pertains to the preparation of vinyl acetate by contacting a mixture of hydrogen and ketene with a heterogeneous catalyst containing a transition metal to produce acetaldehyde, which is then reacted with ketene in the presence of an acid catalyst to produce vinyl acetate.

Tustin, Gerald Charles (Kingsport, TN); Zoeller, Joseph Robert (Kingsport, TN); Depew, Leslie Sharon (Kingsport, TN)

1998-01-01

72

Preparation of vinyl acetate  

DOEpatents

This invention pertains to the preparation of vinyl acetate by contacting a mixture of hydrogen and ketene with a heterogeneous catalyst containing a transition metal to produce acetaldehyde, which is then reacted with ketene in the presence of an acid catalyst to produce vinyl acetate.

Tustin, G.C.; Zoeller, J.R.; Depew, L.S.

1998-03-24

73

Catalytic poly(vinyl alcohol) functionalized membranes obtained by gamma irradiation  

NASA Astrophysics Data System (ADS)

Polymeric catalytic membranes bearing sulfonic acid functions have been prepared by mutual gamma irradiation at a 60Co source, of poly(vinyl alcohol) (PVA) membranes and methanesulfonic acid. The effect of various synthesis conditions on membranes' physical-chemical properties and catalytic activity in the esterification reaction between acetic acid and isoamyl alcohol to obtain isoamyl acetate (banana flavor), was evaluated. The membranes were characterized by ATR-FTIR, TPP, AFM and SEM. Water contact angle determinations were also performed. The obtained results showed that within the range of conditions studied the increase in sulfonic acid groups' content is accompanied by an enhancement in the membranes catalytic activity, while the increase in absorbed dose leads to a decrease in catalytic activity.

Casimiro, M. H.; Silva, A. G.; Pinto, J. V.; Ramos, A. M.; Vital, J.; Ferreira, L. M.

2012-09-01

74

75 FR 61175 - Polyvinyl Alcohol From Taiwan  

Federal Register 2010, 2011, 2012, 2013, 2014

...INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-1088 (Final)] Polyvinyl Alcohol...phase of antidumping investigation No. 731-TA-1088 (Final) under section 735...solution color 20mm cell, 10.0 maximum APHA units, haze index, 20mm cell, 5.0,...

2010-10-04

75

MECHANISM OF DISCOLORATION OF IRRADIATED POLYVINYL CHLORIDE  

Microsoft Academic Search

The radiation chemical process in polyvinyl chloride was studied by ; means of electron spin resonance, optical spectroscopy, and measurement of gas ; evolution. The chief technique was to irradiate sampies at - 196 deg C and then ; follow the change or changes with rising temperature. primary radicals, such as --; CHâ--CH--CHâ-- and -- CHCl -- CH-- CHCl--, were

Shun-Ichi Ohnishi; Yoshiharu Nakajima; Isamu Nitta

1962-01-01

76

Some reactions of dehydrochlorinated polyvinyl chloride  

Microsoft Academic Search

1.Dehydrochlorinated polyvinyl chloride (PVC) is a black polymer, containing a system of conjugated double bonds and possessing unpaired electrons; it adds HCl. In this case, the system of conjugation is disrupted, but the EPR signal is retained.2.In the presence of oxygen, the amount of HCl added to the black polymer is substantially increased (by four to fivefold). The product obtained

É. P. Oleinik; N. S. Vasileiskaya; G. A. Razuvaev

1968-01-01

77

Polyvinyl alcohol: A taste sensing material  

Microsoft Academic Search

There are reports of taste sensor fabrication by incorporating lipids in a PVC matrix. We have taken an attempt to prepare a taste sensor material by using a functionalized polymer. Polyvinyl alcohol (PVA) has been modified to fabricate the sensor material. The research work covers polymer membrane preparation, morphology study, structural characterization of the membrane, and study of the taste

Sarmishtha Majumdar; Basudam Adhikari

2006-01-01

78

Effect of Heat Treatment on Some Mechanical Properties of Laminated Window Profiles Manufactured Using Two Types of Adhesives  

PubMed Central

The mechanical properties of laminated window profiles manufactured using two types of adhesives were determined. The objective of this study is to evaluate the effects of heat treatment on some mechanical properties of laminated window profiles that manufactured from Kosipo (Entandrophragma candollei Harms.) using differenet type adhesives. Commercially produced polyurethane based Macroplast UR 7221 and polyvinyl acetate (PVAc) adhesive were used for experiments. The overall test results were found to be comparable to those obtained in the previous studies. Both types of adhesives resulted in significant differences in their strength characteristics at 95% confidence level. Adhesive UR 7221 improved the overall properties of the samples in contrast to PVAc. PMID:19325761

Korkut, Derya Sevim; Korkutand, Suleyman; Dilik, Tuncer

2008-01-01

79

Polyvinyl alcohol membranes as alkaline battery separators  

Microsoft Academic Search

Polyvinyl alcohol (PVA) cross-linked with aldehyde reagents yields membranes that demonstrate properties that make them suitable for use as alkaline battery separators. Film properties can be controlled by the choice of cross-linker, cross-link density and the method of cross-linking. Three methods of cross-linking and their effects on film properties are discussed. Film properties can also be modified by using a

D. W. Sheibley; O. Gonzalez-Sanabria; M. Manzo

1982-01-01

80

78 FR 20890 - Polyvinyl Alcohol From Taiwan: Preliminary Results of Antidumping Duty Administrative Review...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Administration [A-583-841] Polyvinyl Alcohol From Taiwan: Preliminary Results of Antidumping...the antidumping duty order on polyvinyl alcohol (PVA) from Taiwan. The period of review...Duty Administrative Review: Polyvinyl Alcohol from Taiwan; 2010-2012'' dated...

2013-04-08

81

78 FR 39256 - Polyvinyl Alcohol From Taiwan: Rescission of Antidumping Duty Administrative Review; 2012-2013  

Federal Register 2010, 2011, 2012, 2013, 2014

...Administration [A-583-841] Polyvinyl Alcohol From Taiwan: Rescission of Antidumping...the antidumping duty order on polyvinyl alcohol (PVA) from Taiwan for the period March...CCPC to the Department, ``Polyvinyl Alcohol from Taiwan: Withdrawal of...

2013-07-01

82

Continuous microcellular foaming of polyvinyl chloride and compatibilization of polyvinyl chloride and polylactide composites  

Microsoft Academic Search

This dissertation focuses on overcoming existing limitations of WPCs which prevent them from realizing their full market potential. These limitations include: (i) lack of a continuous extrusion process for microcellular foaming of polyvinyl chloride (PVC) and its composites using supercritical fluids to reduce the high density of the WPCs, (ii) need for an efficient coupling agent for WPCs to overcome

Bhavesh Shah

2007-01-01

83

Preparation of synthetic carbon adsorbents by polyvinyl chloride (PVC) carbonization  

Microsoft Academic Search

Preparation of synthetic carbon adsorbents by carbonization of polyvinyl chloride (produced by Anwil, Wocawek, Poland) is described in the paper. The influence of polyvinyl chloride (PVC) carbonization conditions on the porous structure of the obtained carbon was studied. Part of the prepared carbonizates was activated in the atmosphere of in water vapour and carbon dioxide (600 - 800 oC). The

SECTIO AA; M. Seredych; A. Gierak

84

Flow-Injection Determination of Elemental Iodine by Polyvinyl Alcohol  

Microsoft Academic Search

Complex formation between elemental iodine and polyvinyl alcohol was studied under flow conditions. The formation of substances with a weak hyperchromic effect in the UV and visible regions was detected. It was shown that this reaction could be used under flow conditions provided the gel-forming ability and viscosity of the polyvinyl alcohol solution were reduced by adding isopropanol and 6%

V. V. Kuznetsov; Yu. V. Ermolenko; L. Seffar

2004-01-01

85

Complex compound polyvinyl alcohol-titanic acid/titanium dioxide  

NASA Astrophysics Data System (ADS)

A complex compound polyvinyl alcohol-titanic acid has been produced and investigated by means of IR and Raman spectroscopy, X-ray diffraction, and synchronous thermal analysis. It is claimed that it represents an interpolymeric complex of polyvinyl alcohol and hydrated titanium oxide.

Prosanov, I. Yu.

2013-02-01

86

Effects of Gamma Rays on Aqueous Solution of Polyvinyl Alcohol  

Microsoft Academic Search

The general treatment developed in previous papers is applied to the case where the aqueous solution of polyvinyl alcohol is irradiated by gamma rays and the results are compared with Danno's measurements. The behaviours of irradiated aqueous solution of polyvinyl alcohol before and after gelation are well explained by the author's general theory. It is concluded from the analysis that

Osamu Saito

1959-01-01

87

RESEARCH PAPER Effects of iron oxide nanoparticles on polyvinyl alcohol  

E-print Network

RESEARCH PAPER Effects of iron oxide nanoparticles on polyvinyl alcohol: interfacial layer and bulk:1 and 14 nm for 50:1). The presence of polyvinyl alcohol (PVA) limits the particle growth (15 nm for 20 to the nanoparticle surface, the nanoparticles are found not only to increase the PVA cross-linking with an increase

Guo, John Zhanhu

88

PREPARATION OF POLY(VINYL ACETATE) LATEXES IN LIQUID AND SUPERCRITICAL CARBON DIOXIDE. (R826115)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

89

Nanofiltration of model acetate solutions  

Microsoft Academic Search

Several nanofiltration and reverse osmosis membranes were screened for separating acetic acid from model solutions. Flux increased with pressure and temperature and decreased with pH and concentration of acetate. Rejection increased with pH, probably depending on the degree of dissociation of the acetate. At higher pH, acetate rejection could be correlated with NaCl rejection. Of all the membranes screened, the

I. S. Han; M. Cheryan

1995-01-01

90

Ulipristal acetate: in uterine fibroids.  

PubMed

Ulipristal acetate, a selective progesterone-receptor modulator, inhibits the proliferation and induces apoptosis of leiomyoma cells in vitro. It also modulates the expression of vascular endothelial growth factors and hormone receptors and modulates extracellular matrix breakdown in leiomyoma cells but not in myometrial cells. In two randomized, double-blind, multinational phase III trials of 13 weeks' duration in women aged 18-50 years with uterine fibroids, a once-daily regimen of oral ulipristal acetate 5 mg/day controlled excessive uterine bleeding (primary endpoint) in ?90% of patients. Ulipristal acetate 5 mg/day was more effective than placebo and was shown to be noninferior to intramuscular leuprolide acetate 3.75 mg once monthly in controlling uterine bleeding. Uterine bleeding was rapidly controlled by ulipristal acetate. Approximately half of recipients of ulipristal acetate 5 mg/day became amenorrhoeic within the first 10 days of treatment. Furthermore, uterine bleeding was controlled significantly more rapidly for recipients of ulipristal acetate than recipients of leuprolide acetate. A significantly greater median reduction from baseline in total fibroid volume was observed for recipients of ulipristal acetate 5 mg once daily than recipients of placebo following 13 weeks' treatment (coprimary endpoint). For patients who did not undergo surgery, the volume reduction was maintained for at least 6 months after discontinuing treatment. Ulipristal acetate was generally well tolerated in women with uterine fibroids. The incidence of hot flush occurred with a significantly lower frequency for recipients of ulipristal acetate than for recipients of leuprolide acetate. PMID:22568731

Croxtall, Jamie D

2012-05-28

91

Acetate dependence of tumors.  

PubMed

Acetyl-CoA represents a central node of carbon metabolism that plays a key role in bioenergetics, cell proliferation, and the regulation of gene expression. Highly glycolytic or hypoxic tumors must produce sufficient quantities of this metabolite to support cell growth and survival under nutrient-limiting conditions. Here, we show that the nucleocytosolic acetyl-CoA synthetase enzyme, ACSS2, supplies a key source of acetyl-CoA for tumors by capturing acetate as a carbon source. Despite exhibiting no gross deficits in growth or development, adult mice lacking ACSS2 exhibit a significant reduction in tumor burden in two different models of hepatocellular carcinoma. ACSS2 is expressed in a large proportion of human tumors, and its activity is responsible for the majority of cellular acetate uptake into both lipids and histones. These observations may qualify ACSS2 as a targetable metabolic vulnerability of a wide spectrum of tumors. PMID:25525877

Comerford, Sarah A; Huang, Zhiguang; Du, Xinlin; Wang, Yun; Cai, Ling; Witkiewicz, Agnes K; Walters, Holly; Tantawy, Mohammed N; Fu, Allie; Manning, H Charles; Horton, Jay D; Hammer, Robert E; McKnight, Steven L; Tu, Benjamin P

2014-12-18

92

Preparation of porous super-hydrophobic and super-oleophilic polyvinyl chloride surface with corrosion resistance property  

NASA Astrophysics Data System (ADS)

Porous super-hydrophobic polyvinyl chloride (PVC) surfaces were obtained via a facile solvent/non-solvent coating process without introducing compounds with low surface energy. The microstructure, wetting behavior, and corrosion resistance of resultant super-hydrophobic PVC coatings were investigated in relation to the effects of dosage of glacial acetic acid and the temperature of drying the mixed PVC solution spread over glass slide substrate. As-prepared PVC coatings had porous microstructure, and the one obtained at a glacial acetic acid to tetrahydrofuran volume ratio of 2.5:10.0 and under a drying temperature of 17 °C had a water contact angle of 150 ± 1.5°, showing super-hydrophobicity. In the meantime, it possessed very small contact angles for liquid paraffin and diiodomethane and good corrosion resistance against acid and alkali corrosive mediums, showing promising applications in self-cleaning, waterproof for outer wall of building, seawater resistant coating, and efficient separation of oil and water.

Kang, Yingke; Wang, Jinyan; Yang, Guangbin; Xiong, Xiujuan; Chen, Xinhua; Yu, Laigui; Zhang, Pingyu

2011-11-01

93

Impacts of impregnation with boron compounds on the bonding strength of wood materials  

Microsoft Academic Search

The objective of this research was to evaluate bonding strength of poly(vinyl acetate) (PVAc), polyurethane based Desmodur-VTKA (D-VTKA), phenol–formaldehyde (PF) and melamine–formaldehyde (MF) adhesives to impregnated wood materials. For this purpose, oriental beech (Fagus orientalis lipsky), white oak (Quercus petraea spp.), Uludag fir (Abies bornmülleriana Mattf.) and poplar (Populus nigra) woods were impregnated with borax (Bo), boric acid (Ba), Bo+Ba

Ayhan Özçifçi

2008-01-01

94

Impacts of impregnation chemicals on combustion properties of the laminated wood materials produced combination of beech and poplar veneers  

Microsoft Academic Search

The aim of this study was to investigate the effects of impregnation with boron compounds Borax (BX), Boric acid (BA), BX+BA, Imersol-Aqua (IAQUA) and Timbercare-Aqua (TAQUA) on combustion properties of the laminated wood materials produced combination of Oriental beech and poplar veneers bonded with Desmodur-VTKA (DV) and Poly(vinyl acetate) (PVAc) adhesives. The test samples, prepared from beech (Fagus orientalis Lipsky)

Hakan Keskin; Musa Atar; Mahmut Izciler

2009-01-01

95

Structural performance of the finger-jointed strength of some wood species with different joint configurations  

Microsoft Academic Search

This study was conducted to evaluate the effects of adhesive type, wood species, and finger joint configurations on structural performance of the finger joint. The wood species studied were oriental beech (Fagus orientalis lipsky.), oak (Quercus robur), Scots pine (Pinus sylvestris lipsky.), poplar (Populus tremula lipsk.) and Uluda? fir (Abies bormülleriana Matff.) and adhesives were poly(vinyl acetate) (PVAc), Desmodur-VTKA (D-VTKA).

Ayhan Özçifçi; Fatih Yap?c?

2008-01-01

96

Effects of cold setting adhesives on properties of laminated veneer lumber from oil palm trunks in comparison with rubberwood  

Microsoft Academic Search

In this study, the properties of laminated veneer lumber (LVL) made from oil palm trunks (OPT) were evaluated in comparison\\u000a with rubberwood using cold setting adhesives, namely, emulsion polymeric isocyanate (EPI) and polyvinyl acetate (PVAc). The\\u000a evaluations were based on either dry or after cold water, hot water and cyclic pre-treatment. The density of the OPT LVL was\\u000a slightly higher

Rokiah Hashim; Siti Noorbaini Sarmin; Othman Sulaiman

2011-01-01

97

Properties of laminated veneer lumber (LVL) made with low density hardwood species: effect of the pressure duration  

Microsoft Academic Search

Cross-linked polyvinyl acetate (PVAc) adhesive and thin veneers of three low density wood species,\\u000a namely silver maple, yellow poplar and aspen, were used to produce LVL engineered wood products using different\\u000a press durations. Density, water absorption, thickness swelling, flexural strength and surface hardness\\u000a were evaluated. Internal bond strength, tensile shear and block shear strengths were tested in dry, accelerated\\u000a (boiling

S. R. Shukla; D. Pascal Kamdem

2008-01-01

98

Vapoconductive materials: Mechanisms and sensor applications  

Microsoft Academic Search

Two new conductiometric sensor materials: (1) ferric chloride in poly(vinyl acetate) (PVAc\\/FeCl3) and (2) polyaniline emeraldine base (PaniEB) are reported and used in a device with a previously reported material, tetrabutylammonium triiodide in poly(methyl methacrylate) (PMMA\\/TBAI3) for the detection of vapors. Polymer electrolytes have been shown to exhibit large increases in conductivity when exposed to vapors. This phenomenon has been

Jeffrey Scott Bankers

2004-01-01

99

Electrospinning processed nanofibrous TiO2 membranes for photovoltaic applications  

Microsoft Academic Search

We have recently fabricated dye-sensitized solar cells (DSSCs) comprising nanofibrous TiO2 membranes as electrode materials. A thin TiO2 film was pre-deposited on fluorine doped tin oxide (FTO) coated conducting glass substrate by immersion in TiF4 aqueous solution to reduce the electron back-transfer from FTO to the electrolyte. The composite polyvinyl acetate (PVac)\\/titania nanofibrous membranes can be deposited on the pre-deposited

Katsuhiro Onozuka; Bin Ding; Yosuke Tsuge; Takayuki Naka; Michiyo Yamazaki; Shinichiro Sugi; Shingo Ohno; Masato Yoshikawa; Seimei Shiratori

2006-01-01

100

Acetate Kinase Isozymes Confer Robustness in Acetate Metabolism  

PubMed Central

Acetate kinase (ACK) (EC no: 2.7.2.1) interconverts acetyl-phosphate and acetate to either catabolize or synthesize acetyl-CoA dependent on the metabolic requirement. Among all ACK entries available in UniProt, we found that around 45% are multiple ACKs in some organisms including more than 300 species but surprisingly, little work has been done to clarify whether this has any significance. In an attempt to gain further insight we have studied the two ACKs (AckA1, AckA2) encoded by two neighboring genes conserved in Lactococcus lactis (L. lactis) by analyzing protein sequences, characterizing transcription structure, determining enzyme characteristics and effect on growth physiology. The results show that the two ACKs are most likely individually transcribed. AckA1 has a much higher turnover number and AckA2 has a much higher affinity for acetate in vitro. Consistently, growth experiments of mutant strains reveal that AckA1 has a higher capacity for acetate production which allows faster growth in an environment with high acetate concentration. Meanwhile, AckA2 is important for fast acetate-dependent growth at low concentration of acetate. The results demonstrate that the two ACKs have complementary physiological roles in L. lactis to maintain a robust acetate metabolism for fast growth at different extracellular acetate concentrations. The existence of ACK isozymes may reflect a common evolutionary strategy in bacteria in an environment with varying concentrations of acetate. PMID:24638105

Chan, Siu Hung Joshua; Nørregaard, Lasse; Solem, Christian; Jensen, Peter Ruhdal

2014-01-01

101

Poly(vinyl chloride) processes and products.  

PubMed Central

Poly(vinyl chloride) resins are produced by four basic processes: suspension, emulsion, bulk and solution polymerization. PVC suspensions resins are usually relatively dust-free and granular with varying degrees of particle porosity. PVC emulsion resins are small particle powders containing very little free monomer. Bulk PVC resins are similar to suspension PVC resins, though the particles tend to be more porous. Solution PVC resins are smaller in particle size than suspension PVC with high porosity particles containing essentially no free monomer. The variety of PVC resin products does not lend itself to broad generalizations concerning health hazards. In studying occupational hazards the particular PVC process and the product must be considered and identified in the study. PMID:7333230

Wheeler, R N

1981-01-01

102

Polyvinyl alcohol membranes as alkaline battery separators  

SciTech Connect

Polyvinyl alcohol (PVA) cross-linked with aldehyde reagents yields membranes that demonstrate properties that make them suitable for use as alkaline battery separators. Film properties can be controlled by the choice of cross-linker, cross-link density and the method of cross-linking. Three methods of cross-linking and their effects on film properties are discussed. Film properties can also be modified by using a copolymer of vinyl alcohol and acrylic acid as the base for the separator and cross-linking it similarly to the PVA. Fillers can be incorporated into the films to further modify film properties. Results of separator screening tests and cell tests for several variations of PBA films are discussed.

Sheibley, D.W.; Gonzalez-Sanabria, O.; Manzo, M.

1982-01-01

103

Polyvinyl alcohol cross-linked with two aldehydes  

NASA Technical Reports Server (NTRS)

A film forming polyvinyl alcohol resin is admixed, in aqueous solution, with a dialdehyde crosslinking agent which is capable of crosslinking the polyvinyl alcohol resin and a water soluble acid aldehyde containing a reactive aldehyde group capable of reacting with hydroxyl groups in the polyvinyl alcohol resin and an ionizable acid hydrogen atom. The dialdehyde is present in an amount sufficient to react with from 1 to 20% by weight of the theoretical amount required to react with all of the hydroxyl groups of the polyvinyl alcohol. The amount of acid aldehyde is from 1 to 50% by weight, same basis, and is sufficient to reduce the pH of the aqueous admixture to 5 or less. The admixture is then formed into a desired physical shape, such as by casting a sheet or film, and the shaped material is then heated to simultaneously dry and crosslink the article.

Sheibley, D. W.; Rieker, L. L.; Hsu, L. C.; Manzo, M. A. (inventors)

1982-01-01

104

In Situ Cross-Linking of Polyvinyl Alcohol Films  

NASA Technical Reports Server (NTRS)

Films or impregnated matrices readily made from aqueous polyvinyl alcohol solution. Controlled thickness films made by casting precise quantities of aqueous polymer solution on smooth surface, allowing water to evaporate and then removing film. Composite separators formed in similar fashion by impregnating cloth matrix with polyvinyl alcohol solution and drying composite. Insoluble thin hydrophilic membranes made from aqueous systems, and use of undesirable organic solvents not required.

Philipp, W. H.; Shu, L. C.; May, C. E.

1984-01-01

105

Macroporous polymeric hydrogels formed from acrylate modified polyvinyl alcohol macromers  

Microsoft Academic Search

Macroporous polymeric hydrogels for the last several years have found broad application in areas connected with medicine,\\u000a especially in such new disciplines as cell and tissue engineering. In present work a novel combine approach is proposed for\\u000a preparation of polyvinyl alcohol macroporous hydrogels by cross-linking of polyvinyl alcohol acrylic derivatives in the presence\\u000a of heterophase of frozen aqueous media. Hydrogels

Alexander A. Artyukhov; Mikhail I. Shtilman; Andrey N. Kuskov; Anna P. Fomina; Denis E. Lisovyy; Anna S. Golunova; Aristidis M. Tsatsakis

2011-01-01

106

[Nomegestrol acetate: clinical pharmacology].  

PubMed

Progestogens are used in clinical practice in some conditions. Their effects depend on their chemical structure, pharmacokinetics, pharmacodynamics, with important differences among various progestogens. Generally, progestins are classified according to their parent molecule, of which often they keep some features. Derivatives of 19-nor-progesterone are characterized by high selectivity of action on progestin receptor. In particular, nomegestrol acetate (NomAc) shows an important progestational potency, neutral gluco-lipid profile, and antigonadotropic activity. It is used for treating menstrual cycle disorders and for hormone replacement therapy in menopause in association with an estrogen. In future, thanks to its antigonadotropic activity, NomAc will be used in estroprogestin combinations in fertile women, thus taking advantage of its tolerability profile and obtaining numerous non-contraceptive benefits as well. PMID:19749678

Lello, S

2009-10-01

107

Hydrothermal carbonization of poly(vinyl chloride).  

PubMed

Poly(vinyl chloride) (PVC) was subjected to hydrothermal carbonization in subcritical water at 180-260 °C. Dehydrochlorination increased with increasing reaction temperature. The release of chlorine was almost quantitative above ?235 °C. The fraction of organic carbon (OC) recovered in the hydrochar decreased with increasing operating temperature from 93% at 180 °C to 75% at 250 °C. A wide array of polycyclic aromatic hydrocarbons (PAHs) could be detected in the aqueous phase, but their combined concentration amounted to only ?140 ?g g(-1) PVC-substrate at 240 °C. A pathway for the formation of cyclic hydrocarbons and O-functionalized organics was proposed. Chlorinated hydrocarbons including chlorophenols could only be identified at trace levels (low ppb). Polychlorinated dibenzodioxins (PCDDs) and dibenzofurans (PCDFs) could not be detected. The sorption potential of the hydrochar turned out to be very low, in particular for polar organic pollutants. Our results provide strong evidence that hydrothermal carbonization of household organic wastes which can be tied to co-discarded PVC-plastic residues is environmentally sound regarding the formation of toxic organic products. Following these findings, hydrothermal treatment of PVC-waste beyond operating temperatures of ?235 °C to allow complete release of organic chlorine should be further pursued. PMID:25150971

Poerschmann, J; Weiner, B; Woszidlo, S; Koehler, R; Kopinke, F-D

2015-01-01

108

Preparation and properties of polyvinyl alcohol microspheres  

SciTech Connect

Polyvinyl alcohol (PVA) microspheres, having a size range of approx.150- to 250-..mu..m diameter with 1- to 5-..mu..m wall thickness, have been fabricated using a solution droplet technique. The spheres were developed for possible use on the Lawrence Livermore National Laboratory (LLNL) Inertial Confinement Fusion (ICF) Program. PVA, a polymer chosen based on earlier survey work carried out at KMS Fusion, Inc., has good strength, low hydrogen permeability, is optically transparent, and water soluble. The latter property makes it safe and easy to use in our droplet generator system. A unique dual-orifice droplet generator was used to prepare the spheres. The droplet generator operating conditions and the column processing parameters were chosen using results from our 1-D model calculations as a guide. The polymer microsphere model is an extension of the model we developed to support the glass sphere production. After preparation, the spheres were physically characterized for surface quality, sphericity, wall thickness (and uniformity), and size. We also determined the buckling pressure for both uncoated and CH-coated spheres. Radiation stability to beta decay (from tritium) was evaluated by exposing the spheres to a 7-keV electron beam. The results from these and other physical property measurements are presented in this report.

Campbell, J.H.; Grens, J.Z.; Poco, J.F.; Ives, B.H.

1986-06-01

109

Molecular Structure of Phenylmercuric acetate  

NSDL National Science Digital Library

Phenylmercuric acetate is white to white-yellow crystalline powder that is odorless. This phenyl mercury compound is used mainly as a fungicide, herbicide, slimicide and bacteriocide. Phenylmercuric acid serves as a preservative in canned paint, eye ointments and drops, injectable solutions, skin disinfectants and in cosmetics products such as hair shampoos, mouthwashes and toothpastes. It is also used in contraceptive gels and foams. Phenylmercuric acetate is prepared by interaction of benzene with mercuric acetate in glacial acetic acid. Phenylmercuric acetate's former production and use as a fungicide and as a mildew inhibitor in paints may have resulted in its direct release to the environment. This substance is very toxic to aquatic organisms and may be hazardous to the environment.

2004-11-10

110

Preparation and characterization of film of poly vinyl acetate ethylene copolymer emulsion  

NASA Astrophysics Data System (ADS)

In order to improve the storage modulus and water resistance of poly (vinyl acetate), the vinyl acetate and poly (vinyl alcohol) (PVA) were respectively used as monomers and protective colloid to prepare a new kind of polyvinyl acetate emulsion adhesive by continuous emulsion polymerization. The dynamic mechanics, particle distribution, glass transition temperature, polymer emulsion structure of both polymerized and copolymerized emulsion were analyzed by SEM, DMA and XPS, respectively. The results indicated that the copolymerized emulsion has the appropriate particle size and the uniform particle distribution, the glass transition temperature increased from 50 °C to 70 °C, compared with poly (vinyl acetate). It could be seen from XPS spectra of copolymerized emulsion that key characteristic peak of Cdbnd O was still existent. X-ray photoelectron spectra revealed that the addition of EVA did not generate the new bond, whereas the maximum percentage increases in ester was determined in the composite film with the introduction of EVA of 25%, which indicated that the composite film has copolymer structure. The storage modulus and water resistance of poly (vinyl acetate) were improved due to the introduction of the EVA.

Zhang, Yanhua; Gu, Jiyou; Tan, Haiyan; Shi, Junyou; Di, Mingwei; Zuo, Yingfeng; Qiu, Si

2013-07-01

111

Ulipristal acetate for emergency contraception.  

PubMed

Ulipristal acetate is a progesterone receptor modulator. As an emergency contraceptive, a 30-mg micronized formulation is effective for use up to 120 h from unprotected sexual intercourse. Ulipristal acetate acts as an antagonist of the progesterone receptor at the transcriptional level and a competitive antagonist of glucocorticoid receptor function. In contrast to other contraceptives, it has little effect on sex hormone-binding globulin. Although a single small study demonstrated some potential endometrial effects after ulipristal acetate administration, the clinical relevance of these findings is unclear. The incidence of adverse events in clinical trials for emergency contraception has typically been minimal, with one study showing a higher than expected incidence of nausea upon ulipristal acetate use. Ulipristal acetate, like other emergency contraceptive products, can lengthen the time to the next expected menstruation. Ulipristal acetate may have several advantages over currently approved emergency contraceptives. When compared to levonorgestrel, ulipristal acetate maintains its efficacy for a full 120 h, whereas levonorgestrel formulations have declining efficacy over that time frame. Moreover, although the copper intrauterine device (IUD) is highly effective as an emergency contraceptive, accessibility is an issue since the IUD requires a skilled provider for insertion. PMID:20967297

Russo, J A; Creinin, M D

2010-09-01

112

Molecular Structure of Sodium acetate  

NSDL National Science Digital Library

Sodium acetate is known for its ability to supercool. It freezes at 130 degrees, but can exist as a liquid at a much lower temperature. In order to melt solidified sodium acetate, however, every single crystal must liquify, otherwise the material will recrystallize. Sodium acetate has been used as a deicer for roads and runways. It is also used a component of buffer systems and in the manufacture of pharmaceuticals and heat pads. The compound is quite stable. It may act as an irritant and be harmful if inhaled or absorbed through the skin.

2002-08-26

113

Ulipristal acetate: contraceptive or contragestive?  

PubMed

Ulipristal acetate is the first selective progesterone receptor modulator approved for postcoital contraception in the US. It appears to be significantly more effective in inhibition of ovulation than other forms of emergency contraception. However, ulipristal acetate is structurally similar to mifepristone, and several lines of evidence suggest that a postfertilization mechanism of action is also operative. This mechanism of action is considered to be contragestive versus contraceptive. Ulipristal acetate administration is contraindicated in a known or suspected pregnancy; however, it could quite possibly be used as an effective abortifacient. Health-care providers should inform patients of the possibility of both mechanisms of action with use of this drug. PMID:21666088

Keenan, Jeffrey A

2011-06-01

114

40 CFR 61.64 - Emission standard for polyvinyl chloride plants.  

Code of Federal Regulations, 2010 CFR

...polyvinyl chloride plants. An owner or operator...polyvinyl chloride plant shall comply with...postpolymerization. (3) Manual vent valve discharge...atmosphere from any manual vent valve...the reactor if the plant has no...

2010-07-01

115

Radiation-chemical preparation of poly(vinyl alcohol) hydrogels  

NASA Astrophysics Data System (ADS)

This work reports the usage of method of radiation-chemical synthesis to prepare cross-linked hydrogels from poly(vinyl alcohol) modified with glycidyl methacrylate. Synthesis kinetics of modified poly(vinyl alcohol) and properties of hydrogels were studied. The gel fraction, swelling, mechanical properties, and water content of the hydrogels were measured. It was found that gel fraction increases with increasing radiation dose, concentration of modified poly(vinyl alcohol), and reaches 60%. It was established by differential scanning calorimetry that a fraction of the 'bound' water in hydrogels is 50-70% and independent of gel fraction content. In addition to 'bound' and 'free' states, water in hydrogels is also present in the intermediate state.

Duflot, Anastasia V.; Kitaeva, Natalia K.; Duflot, Vladimir R.

2015-02-01

116

Molecular Structure of Acetic acid  

NSDL National Science Digital Library

Acetic Acid commonly associated with vinegar; it is the most commercially important organic acid and is used to manufacture a wide range of chemical products, such as plastics and insecticides. Acetic acid is produced naturally by Aceto bacteria but, except for making vinegar, is usually made through synthetic processes. Ethanoic acid is used as herbicide, as a micro-biocide, as a fungicide and for pH adjustment.

2003-06-02

117

Strength of modified polyvinyl chloride films taking account of operating conditions  

Microsoft Academic Search

Experimental data are given for the strength and deformability of a wide range of polyvinyl chloride films obtained by combining different grades of polyvinyl chlorides and modifiers. The effect is considered of temperature and longterm climatic factors on the strength of these materials. The possibility is demonstrated of predicting the change in deformability of polyvinyl chloride films under conditions of

É. S. Umanskii; N. S. Shidlovskii; L. L. Stezhko; V. V. Kryuchkov; V. L. Nikityuk

1990-01-01

118

Poly(vinyl alcohol) (PVA)/sulfonated polyhedral oligosilsesquioxane (sPOSS) hybrid membranes  

E-print Network

Poly(vinyl alcohol) (PVA)/sulfonated polyhedral oligosilsesquioxane (sPOSS) hybrid membranes/inorganic hybrid membranes based on poly(vinyl alcohol) (PVA) and sulfonated polyhedral oligosilsesquioxane (s membrane. Copyright # 2007 John Wiley & Sons, Ltd. KEYWORDS: poly(vinyl alcohol) (PVA); sulfonated

Mather, Patrick T.

119

Effect of Microwave Irradiation on the Cross-Linking of Polyvinyl Alcohol  

Microsoft Academic Search

The possibility of dehydration (cross-linking) of polyvinyl alcohol upon microwave irradiation of thin polymer films was examined. The properties of polyvinyl alcohol samples treated by convection heating and irradiation were compared. Immobilization of polyvinyl alcohol on polymer matrices by microwave irradiation was studied.

N. V. Petrova; A. M. Evtushenko; I. P. Chikhacheva; V. P. Zubov; I. V. Kubrakova

2005-01-01

120

Polyvinyl alcohol battery separator containing inert filler. [alkaline batteries  

NASA Technical Reports Server (NTRS)

A cross-linked polyvinyl alcohol battery separator is disclosed. A particulate filler, inert to alkaline electrolyte of an alkaline battery, is incorporated in the separator in an amount of 1-20% by weight, based on the weight of the polyvinyl alcohol, and is dispersed throughout the product. Incorporation of the filler enhances performance and increases cycle life of alkaline batteries when compared with batteries containing a similar separator not containing filler. Suitable fillers include titanates, silicates, zirconates, aluminates, wood floor, lignin, and titania. Particle size is not greater than about 50 microns.

Sheibley, D. W.; Hsu, L. C.; Manzo, M. A. (inventors)

1981-01-01

121

Photooxidative degradation of carboxylated poly(vinyl chloride)  

Microsoft Academic Search

Thin films of poly(vinyl chloride), PVC, and carboxylated poly(vinyl chloride), C-PVC, containing 1.8% of carboxyl groups\\u000a were exposed to high energy ultraviolet radiation (? = 254 nm) in laboratory conditions. The photochemical reactions in irradiated\\u000a samples were studied by FTIR and UV–Vis spectroscopy, gel permeation chromatography and gravimetric estimation of insoluble\\u000a gel. It was found that photodegradation and photocrosslinking in C-PVC is accelerated,

Halina Kaczmarek; Agnieszka Felczak; Dagmara Bajer

2009-01-01

122

The polyvinyl alcohol sponge model implantation.  

PubMed

Wound healing is a complicated, multistep process involving many cell types, growth factors and compounds(1-3). Because of this complexity, wound healing studies are most comprehensive when carried out in vivo. There are many in vivo models available to study acute wound healing, including incisional, excisional, dead space, and burns. Dead space models are artificial, porous implants which are used to study tissue formation and the effects of substances on the wound. Some of the commonly used dead space models include polyvinyl alcohol (PVA) sponges, steel wire mesh cylinders, expanded polytetrafluoroethylene (ePTFE) material, and the Cellstick(1,2). Each dead space model has its own limitations based on its material's composition and implantation methods. The steel wire mesh cylinder model has a lag phase of infiltration after implantation and requires a long amount of time before granulation tissue formation begins(1). Later stages of wound healing are best analyzed using the ePTFE model(1,4). The Cellstick is a cellulose sponge inside a silicon tube model which is typically used for studying human surgery wounds and wound fluid(2). The PVA sponge is limited to acute studies because with time it begins to provoke a foreign body response which causes a giant cell reaction in the animal(5). Unlike other materials, PVA sponges are easy to insert and remove, made of inert and non-biodegradable materials and yet are soft enough to be sectioned for histological analysis(2,5). In wound healing the PVA sponge is very useful for analyzing granulation tissue formation, collagen deposition, wound fluid composition, and the effects of substances on the healing process(1,2,5). In addition to its use in studying a wide array of attributes of wound healing, the PVA sponge has also been used in many other types of studies. It has been utilized to investigate tumor angiogenesis, drug delivery and stem cell survival and engraftment(1,2,6,7). With its great alterability, prior extensive use, and reproducible results, the PVA sponge is an ideal model for many studies(1,2). Here, we will describe the preparation, implantation and retrieval of PVA sponge disks (Figure 1) in a mouse model of wound healing. PMID:22546933

Deskins, Desirae L; Ardestani, Shidrokh; Young, Pampee P

2012-01-01

123

Electrically Conducting Polymer-Copper Sulphide Composite Films, Preparation by Treatment of Polymer-Copper (2) Acetate Composites with Hydrogen Sulfide  

NASA Technical Reports Server (NTRS)

Polymer copper sulfide composite films were prepared by treatment of polymer poly(vinyl chloride), poly(acrylonitrile), copolymer of vinyl chloride and vinyl acetate (90:10), and ABS resin copper (2) acetate composites with hydrogen sulfide. The films showed electrical conductivity higher than 0.015 S/cm when they contained more than 20 wt percent of copper sulfide. A poly(acrylonitrile)-copper sulfide composite film containing 40 to 50 wt percent of copper sulfide showed electrical conductivity of 10 to 150.0 S/cm and had relatively high mechanical strength to be used in practical purposes.

Yamamoto, Takakazu; Kamigaki, Takahira; Kubota, Etsuo

1988-01-01

124

Anammox sludge immobilized in polyvinyl alcohol (PVA) cryogel carriers  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study evaluated the use of polyvinyl alcohol (PVA) cryogels to encapsulate slow-growing anammox bacteria for deammonification treatment of wastewater. The cryogel pellets were prepared by a freezing-thawing procedure at -8 oC. On average, pellets contained 11.8 mg TSS/g-pellet of enriched anamm...

125

EXPOSURE TO CHEMICAL ADDITIVES FROM POLYVINYL CHLORIDE POLYMER EXTRUSION PROCESSING  

EPA Science Inventory

This report presents a model to predict worker inhalation exposure due to off-gassing of additives during polyvinyl chloride (PVC) extrusion processing. ata on off-gassing of additives were reviewed in the literature, the off-gassing at normal PVC processing temperatures was stud...

126

1 INTRODUCTION In Spain, Plasticized polyvinyl chloride (PVC-  

E-print Network

1 INTRODUCTION In Spain, Plasticized polyvinyl chloride (PVC- P) geomembranes began being used in waterproof- ing of infrastructure in the seventies. Early usage of PVC-P geomembranes was not particularly for the PVC-P homogeneous geomem- branes used in roofing. Subsequently, other stan- dards were drafted

Zornberg, Jorge G.

127

Flow-induced swelling of poly(vinyl alcohol) gel  

Microsoft Academic Search

Flow and swelling behavior was investigated for poly(vinyl alcohol) (PVA) gel in the solvent flow field. It was found that the PVA gel swelled under solvent flow and the volume of the gel increased with increasing solvent pressure. The flow rate also increased with increasing solvent pressure. On the other hand, the characteristic times determined by swelling and flow kinetics

T. Takigawa; K. Uchida; K. Takahashi; T. Masuda

1999-01-01

128

Using polyvinyl chloride dyed with bromocresol purple in radiation dosimetry  

Microsoft Academic Search

Polyvinyl chloride (PVC) dyed with bromocresol purple was investigated as a high-dose radiation dosimeter. The absorbance at 417nm depends linearly on the dose below 50kGy. The response depends neither on dose rate nor on the irradiation temperature. The effects of post-irradiation storage in the dark and in indirect sunlight are also discussed.

Munzer Kattan; Haroun al Kassiri; Yarob Daher

2011-01-01

129

Using polyvinyl chloride dyed with bromocresol purple in radiation dosimetry.  

PubMed

Polyvinyl chloride (PVC) dyed with bromocresol purple was investigated as a high-dose radiation dosimeter. The absorbance at 417 nm depends linearly on the dose below 50 kGy. The response depends neither on dose rate nor on the irradiation temperature. The effects of post-irradiation storage in the dark and in indirect sunlight are also discussed. PMID:21109445

Kattan, Munzer; al Kassiri, Haroun; Daher, Yarob

2011-02-01

130

Lung function in workers exposed to polyvinyl chloride dust  

Microsoft Academic Search

Several reported studies on the effects of polyvinyl chloride (PVC) dust in animals and man have been conflicting. The present study of the ventilatory function of 509 male workers exposed to PVC dust was made in 1977. Altogether 104 men exposed to PVC dust only, 112 men exposed to non-chlorinated solvents only, and 293 men exposed to a mixture of

C P Chivers; C Lawrence-Jones; G M Paddle

1980-01-01

131

Immobilization of enzymes in photochemically cross-linked polyvinyl alcohol  

Microsoft Academic Search

Invertase and amyloglucosidase were entrapped in polyvinyl alcohol membranes through UV irradiation of pendent styrylpyridinium groups. The influence of cross-linking on immobilization efficiency was studied using prepolymers with varied cross-linker density, the above mentioned enzymes of different molecular weight, and various substrates. It was found that the larger enzyme invertase is effectively immobilized even in polymers with very low contents

Thomas Uhlich; Mathias Ulbricht; Georg Tomaschewski

1996-01-01

132

Novel Low Flammable Coating Based on Polyvinyl Alcohol  

Microsoft Academic Search

A new type of polymer varnish (coating) based on Polyvinyl Alcohol was developed using potassium permanganate oxidation in water solution. The flammability of this coating was tested using Cone Calorimeter. All tests on flammability indicated an increase of flame retardancy of this polymer coating due to carbonization of cross-linked polymer fragments.

Guennadi E. Zaikov; Sergei M. Lomakin

1997-01-01

133

Treatment of desizing wastewater containing poly(vinyl alcohol) by wet air oxidation  

SciTech Connect

The effectiveness of wet air oxidation (WAO) is studied in a 2-L autoclave for the treatment of desizing wastewater from man-made fiber textile plants. At an oxygen pressure of less than 2 MPa, over 30-min, chemical oxygen demand (COD) removal was found to increase from 15 to 65% when the temperature was raised from 150 to 250 C. The biodegradability of the wastewater was also simultaneously increased. Up to 90% of the COD could be removed within 120 min. A simplified reaction mechanism is proposed which involves a direct mineralization step in parallel with a step in which an intermediate is formed prior to mineralization. A kinetic model for COD removal was developed based on this reaction mechanism. The model was tested with experimental COD results over the temperature range of the experiments. The dependence of the specific reaction rate constants was found to follow the Arrhenius type of equation. The direct oxidation of poly(vinyl alcohol) (PVA) to carbon dioxide and water is the dominant reaction step. The intermediates formed are not likely to be the acetic acid but may be short segments of PVA that are easily oxidized.

Chen, G.; Lei, L.; Yue, P.L.; Cen, P.

2000-05-01

134

DNA capillary electrophoresis using poly(vinyl alcohol). I. Inner capillary coating.  

PubMed

Two new methods of inner capillary coating with poly(vinyl alcohol) (PVAL) have been investigated and evaluated by performing DNA capillary electrophoresis (CE) using PVAL as a separation medium and by measuring the electroosmotic flow (EOF) mobility. The treatment of capillaries with a silanol-group modified PVAL (PVAL-Si) has been found to give good coating effects for improving the resolution of DNA CE and for reducing the EOF. This coating must be effectively achieved by combining the adsorptive property of PVAL chains onto silica with the reaction between the silanol groups of PVAL-Si and the silica surface. The adsorption of PVAL onto silica has been observed by using atomic force microscopy (AFM) for PVAL-Si as well as for a nonmodified PVAL as a control. The coating with PVAL that links to the capillary wall surface with more hydrolytically stable bonding, -Si-C-, has been formed by performing the Grignard reaction, followed by in-capillary polymerization of vinyl acetate (VAc) and hydrolysis. This coating has been found to be effective for improving the resolution of DNA CE and for reducing the EOF. PMID:12929172

Moritani, Tohei; Yoon, Kyunghwan; Rafailovich, Miriam; Chu, Benjamin

2003-08-01

135

Desmopressin Acetate in Intracranial Haemorrhage  

PubMed Central

Introduction. The secondary increase in the size of intracranial haematomas as a result of spontaneous haemorrhage or trauma is of particular relevance in the event of prior intake of platelet aggregation inhibitors. We describe the effect of desmopressin acetate as a means of temporarily stabilising the platelet function. Patients and Methods. The platelet function was analysed in 10 patients who had received single (N = 4) or multiple (N = 6) doses of acetylsalicylic acid and 3 patients (control group) who had not taken acetylsalicylic acid. All subjects had suffered intracranial haemorrhage. Analysis was performed before, half an hour and three hours after administration of desmopressin acetate. Statistical analysis was performed by applying a level of significance of P ? 0.05. Results. (1) Platelet function returned to normal 30 minutes after administration of desmopressin acetate. (2) The platelet function worsened again after three hours. (3) There were no complications related to electrolytes or fluid balance. Conclusion. Desmopressin acetate can stabilise the platelet function in neurosurgical patients who have received acetylsalicylic acid prior to surgery without causing transfusion-related side effects or a loss of time. The effect is, however, limited and influenced by the frequency of drug intake. Further controls are needed in neurosurgical patients. PMID:25610644

Kapapa, Thomas; Röhrer, Stefan; Struve, Sabine; Petscher, Matthias; König, Ralph; Wirtz, Christian Rainer; Woischneck, Dieter

2014-01-01

136

Concentrating aqueous acetate solutions with tertiary amines  

E-print Network

= I'7o(w/wk) 11 Liquid-liquid equilibrium data for the calcium acetate/water/amuie system with various extractants. (T= TEA, D= DEMA. Initial aqueous-phase calcium acetate concentration= 2%(w/w). ) 27 28 31 34 via FIGURE Page 12 Liquid.... (Calcium acetate/water /amine, TEA:DEMA= I mL:2 mL, initial aqueous calcium acetate= 1% (w/w). ) Equilibrium calcium acetate concentrations in the aqueous phase determined by FTIR and AA measurements. (Calcium acetate/water /amine, TEA:DEMA= I mL;2 m...

Lee, Champion

1993-01-01

137

Cross-linked polyvinyl alcohol and method of making same  

NASA Technical Reports Server (NTRS)

A film-forming polyvinyl alcohol polymer is mixed with a polyaldehyde-polysaccharide cross-linking agent having at least two monosaccharide units and a plurality of aldehyde groups per molecule, perferably an average of at least one aldehyde group per monosaccharide units. The cross-linking agent, such as a polydialdehyde starch, is used in an amount of about 2.5 to 20% of the theoretical amount required to cross-link all of the available hydroxyl groups of the polyvinyl alcohol polymer. Reaction between the polymer and cross-linking agent is effected in aqueous acidic solution to produce the cross-linked polymer. The polymer product has low electrical resistivity and other properties rendering it suitable for making separators for alkaline batteries.

Hsu, L. C.; Sheibley, D. W.; Philipp, W. H. (inventors)

1981-01-01

138

Polyvinyl Alcohol Based Membrane as Separator for Alkaline Water Electrolyzer  

Microsoft Academic Search

Alkaline water Electrolyzer employs Nickel based electrodes and asbestos cloth diaphragm. Asbestos is considered as carcinogenic. In order to limit the usage of asbestos diaphragm, separator membrane was synthesized from polyvinyl alcohol, glutaraldehyde, N,N,N'N'-Tetramethyl hexane-1,6 diamine and Titanium dioxide. The role of N,N,N'N'-Tetramethyl hexane-1,6 diamine is to improve the dimensional stability of the membrane. The fabricated membranes were characterized by

S. Seetharaman; S. Ravichandran; D. J. Davidson; S. Vasudevan; G. Sozhan

2011-01-01

139

Immobilization of lipase enzyme in polyvinyl alcohol (PVA) nanofibrous membranes  

Microsoft Academic Search

Lipase enzyme from Candida rugosa (E.C. 3.1.1.3) has been successfully immobolized in 100–500nm diameter fibers via electrospinning of aqueous mixtures of lipase and polyvinyl alcohol (PVA). Enzyme loading in these bicomponent fibers reached as high as 50%. The catalytic activity of the fiber bound lipase was the same as the crude enzyme, showing no adverse effects from either electric charges

Y. Wang; Y.-L. Hsieh

2008-01-01

140

Study on morphology of electrospun poly(vinyl alcohol) mats  

Microsoft Academic Search

Submicron poly(vinyl alcohol) (PVA) fiber mats were prepared by electrospinning of aqueous PVA solutions in 6–8% concentration. Fiber morphology was observed under a scanning electron microscope and effects of instrument parameters including electric voltage, tip–target distance, flow rate and solution parameters such as concentration on the morphology of electrospun PVA fibers were evaluated. Results showed that, when PVA with higher

Chunxue Zhang; Xiaoyan Yuan; Lili Wu; Yue Han; Jing Sheng

2005-01-01

141

Water resistance of photocrosslinked polyvinyl alcohol based fibers  

Microsoft Academic Search

Electrospinning and photocrosslinking were combined in this study to prepare water-insoluble fibers of polyvinyl alcohol (PVA) with the styrylpyridinium (SbQ) pendent group. The PVA-SbQ exhibited high photosensitivity in a spectroscopic study. Electrospun PVA and PVA-SbQ fibers were soluble and totally dissolved after water immersion. UV irradiation of the electrospun mat led to a significant decrease in the mass loss of

Yurong Liu; Brian Bolger; Paul A. Cahill; Garrett B. McGuinness

2009-01-01

142

Fabrication and characterization of conducting polyvinyl alcohol nanofibers  

Microsoft Academic Search

Conducting polyvinyl alcohol (PVA) nanofibers with diameters ranging from 100nm to 300nm were fabricated by an electrospinning method from spinning dopes of the dissolved PVA polymer in aqueous dispersion of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS). Using a chemical cross-linking agent, glutaraldehyde (GA), water insoluble conducting PVA nanofibers were obtained through an in-situ crosslinking of PVA polymer during electrospinning. The cross-linked conducting nanofibers

Daehwan Cho; Nikolas Hoepker; Margaret W. Frey

143

Preparation and properties of microfibrillated cellulose polyvinyl alcohol composite materials  

Microsoft Academic Search

This work reports the preparation of MFC–PVA composite films, and the thermal and mechanical properties of these films. Microfibrillated cellulose (MFC), which was separated from kraft pulp by a mechanical process, was used as the reinforcement in polyvinyl alcohol (PVA) matrix. This MFC reinforcement has an interconnected web-like structure with fibrils having a diameter in the range of 10–100nm, as

Jue Lu; Tao Wang; Lawrence T. Drzal

2008-01-01

144

Epoxidation of thermally degraded poly(vinyl chloride)  

Microsoft Academic Search

Epoxidation of conjugated polyenes formed by thermal degradation of poly(vinyl chloride) (PVC) was carried out in cyclohexanone and tetrahydrofuran solution with m-chloroperoxybenzoic acid (mCPBA). PVC was thermally degraded in the solid state under continuous nitrogen flow at 200 °C for 30 min leading to 0.6 mol% double bonds in the polymer chain as determined from the UV-visible spectrum of the

Tibor Szakács; Béla Iván

2004-01-01

145

Cross-linked polyvinyl alcohol films as alkaline battery separators  

Microsoft Academic Search

Cross-linking methods have been investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: PVA-dialdehyde blends post-treated with an acid or acid periodate solution and PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid functionality. Laboratory samples

Dean W. Sheibley; O. D. Gonzalez-Sanabria; M. A. Manzo

1983-01-01

146

Cross-linked polyvinyl alcohol and method of making same  

Microsoft Academic Search

A film-forming polyvinyl alcohol polymer is mixed with a polyaldehyde-polysaccharide cross-linking agent having at least two monosaccharide units and a plurality of aldehyde groups per molecule, preferably an average of at least one aldehyde group per monosaccharide units. The cross-linking agent, such as a polydialdehyde starch, is used in an amount of about 2.5 to 20% of the theoretical amount

L. Hsu; W. H. Philipp; D. W. Sheibley

1981-01-01

147

Humidity sensors using polyvinyl alcohol mixed with electrolytes  

Microsoft Academic Search

Resistive-type humidity sensors were fabricated by casting polyvinyl alcohol on comb-shaped electrodes. The impedance of the PVA film decreased with increasing relative humidity (RH), the best sensing behavior being attained at a film thickness of 10 ?m. The addition of p-styrenesulfonate sodium (PSSD), sodium chloride or m-benzenedisulfonate disodium (MBSD) to the PVA film was effective for improving the humidity sensitivity.

Mu-Rong Yang; Ko-Shao Chen

1998-01-01

148

Adsorptive Selectivity of DNA\\/Polyvinyl Alcohol Interpenetrating Polymer Networks  

Microsoft Academic Search

An interpenetrating polymer network (IPN) containing natural DNA was prepared by cross-linking polyvinyl alcohol (PVA) with a glutaraldehyde (GA) reagent and then cross-linking DNA with UV irradiation. This DNA\\/PVA IPN structure could selectively bind chemicals with affinity for DNA, and adsorb L-tryptophan (L-Trp) with a high chiral-selectivity over D-Trp. More than ten times more L-Trp was adsorbed on the DNA\\/PVA

XiangDong Liu; Tetsuro Kubo; WenXing Chen; Jonganurakkun Benjamas; Tomomi Yonemichi; Norio Nishi

2011-01-01

149

Cross-linked polyvinyl alcohol films as alkaline battery separators  

Microsoft Academic Search

Cross-linking methods were investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: (1) PVA-dialdehyde blends post-treated with an acid or acid periodate solution (two-step method) and (2) PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid

D. W. Sheibley; M. A. Manzo; O. D. Gonzalez-Sanabria

1982-01-01

150

Ozone decomposition in aqueous acetate solutions  

SciTech Connect

The acetate radical ion reacts with ozone with a rate constant of k = (1.5 +/- 0.5) x 10Z dmT mol s . The products from this reaction are CO2, HCHO, and O2 . By subsequent reaction of the peroxy radical with ozone the acetate radical ion is regenerated through the OH radical. A chain decomposition of ozone takes place. It terminates when the acetate radical ion reacts with oxygen forming the unreactive peroxy acetate radical. The chain is rather short as oxygen is developed, as a result of the ozone consumption. The inhibiting effect of acetate on the ozone decay is rationalized by OH scavenging by acetate and successive reaction of the acetate radical ion with oxygen. Some products from the bimolecular disappearance of the peroxy acetate radicals, however, react further with ozone, reducing the effectiveness of the stabilization.

Sehested, K.; Holcman, J.; Bjergbakke, E.; Hart, E.J.

1987-01-01

151

40 CFR 414.40 - Applicability; description of the thermoplastic resins subcategory.  

Code of Federal Regulations, 2012 CFR

...Resins Polyvinyl Acetate *Polyvinyl Acetate—PVC Copolymers *Polyvinyl Acetate Copolymers ...*Polyvinylidene-Vinyl Chloride Resins *PVC Copolymers, Acrylates (Latex) *PVC Copolymers, Ethylene-Vinyl Chloride...

2012-07-01

152

40 CFR 414.40 - Applicability; description of the thermoplastic resins subcategory.  

Code of Federal Regulations, 2014 CFR

...Resins Polyvinyl Acetate *Polyvinyl Acetate—PVC Copolymers *Polyvinyl Acetate Copolymers ...*Polyvinylidene-Vinyl Chloride Resins *PVC Copolymers, Acrylates (Latex) *PVC Copolymers, Ethylene-Vinyl Chloride...

2014-07-01

153

40 CFR 414.40 - Applicability; description of the thermoplastic resins subcategory.  

Code of Federal Regulations, 2013 CFR

...Resins Polyvinyl Acetate *Polyvinyl Acetate—PVC Copolymers *Polyvinyl Acetate Copolymers ...*Polyvinylidene-Vinyl Chloride Resins *PVC Copolymers, Acrylates (Latex) *PVC Copolymers, Ethylene-Vinyl Chloride...

2013-07-01

154

40 CFR 414.40 - Applicability; description of the thermoplastic resins subcategory.  

Code of Federal Regulations, 2011 CFR

...Resins Polyvinyl Acetate *Polyvinyl Acetate—PVC Copolymers *Polyvinyl Acetate Copolymers ...*Polyvinylidene-Vinyl Chloride Resins *PVC Copolymers, Acrylates (Latex) *PVC Copolymers, Ethylene-Vinyl Chloride...

2011-07-01

155

Genera and species in acetic acid bacteria  

Microsoft Academic Search

Taxonomic studies of acetic acid bacteria were historically surveyed. The genus Acetobacter was first introduced in 1898 with a single species, Acetobacter aceti. The genus Gluconobacter was proposed in 1935 for strains with intense oxidation of glucose to gluconic acid rather than oxidation of ethanol to acetic acid and no oxidation of acetate. The genus “Acetomonas\\

Yuzo Yamada; Pattaraporn Yukphan

2008-01-01

156

Formation of Linear Polyenes in Thermal Dehydration of Polyvinyl Alcohol, Catalyzed by Phosphotungstic Acid  

NASA Astrophysics Data System (ADS)

In order to obtain linear polyenes in polyvinyl alcohol films via acid-catalyzed thermal dehydration of the polyvinyl alcohol, we used phosphotungstic acid as the catalyst: a safe and heat-stable solid chemical compound. We established that phosphotungstic acid, introduced as solid nanoparticles into polyvinyl alcohol films, is a more effective dehydration catalyst than hydrochloric acid, since in contrast to HCl it does not evaporate from the film during heat treatment.

Tretinnikov, O. N.; Sushko, N. I.

2015-01-01

157

Improving performance of polyvinyl acetate (PVA) as a binder for wood by combination with melamine based adhesives  

Microsoft Academic Search

In this study blending PVA with MUF and MF was evaluated as an approach to enhance the performance of PVA towards water and elevated temperatures. MF and MUF were added to PVA at different proportions: 15%, 30%, 50%, 70% and 100%. Blends of PVA with MF and MUF were used as adhesives to bond wood joints. The shear strength of

Alireza Kaboorani; Bernard Riedl

2011-01-01

158

Effect of composite microstructure on electrical and mechanical properties of poly(vinyl acetate) composites with carbon black and clay.  

E-print Network

-based) from those with random dispersion (solution-based) of the filler. The percolation thresholds for the emulsion-based composites were near 1.2 vol% carbon black, while the solution-based composites were around 8.2 vol% carbon black. This difference is due...

Miriyala, Sethu M.

2009-05-15

159

Biodegradation of cellulose acetate by Neisseria sicca.  

PubMed

Bacteria capable of assimilating cellulose acetate, strains SB and SC, were isolated from soil on a medium containing cellulose acetate as a carbon source, and identified as Neisseria sicca. Both strains degraded cellulose acetate membrane filters (degree of substitution, DS, mixture of 2.8 and 2.0) and textiles (DS, 2.34) in a medium containing cellulose acetate (DS, 2.34) or its oligomer, but were not able to degrade these materials in a medium containing cellobiose octaacetate. Biodegradation of cellulose acetate (DS, 1.81 and 2.34) on the basis of biochemical oxygen demand reached 51 and 40% in the culture of N. sicca SB and 60 and 45% in the culture of N. sicca SC within 20 days. A decrease in the acetyl content of degraded cellulose acetate films and powder was confirmed by infrared and nuclear magnetic resonance analyses. After 10-day cultivation of N. sicca SB and SC, the number-average molecular weight of residual cellulose acetate decreased by 9 and 5%, respectively. Activities of enzymes that released acetic acid and produced reducing sugars from cellulose acetate were mainly present in the culture supernatant. Reactivity of enzymes for cellulose acetate (DS, 1.81) was higher than that for cellulose acetate (DS, 2.34). PMID:8987659

Sakai, K; Yamauchi, T; Nakasu, F; Ohe, T

1996-10-01

160

Molecular Structure of Ethyl acetate  

NSDL National Science Digital Library

Ethyl acetate is a colorless, volatile liquid with a mild and fragrant odor. It is used as solvent in chemistry laboratories but can also be found in many household products such as paints, coatings, and adhesives. The compound is also used in some extraction processes such as decaffeination or purification of antibiotics. It is present in both nail polish and removers. Some synthetic fruit essences may contain this and other esters. Etymologists like to use this solvent for insect collecting as the vapor kill the insect quickly and keep it soft for mounting.

2006-03-08

161

[Antiovulatory action of chlormadinone acetate].  

PubMed

Antiovulatory action of chlormadinone acetate (5 mg twice daily from day 7 to day 25) has been assessed in 6 healthy volunteers by daily determination of plasma FSH, LH, estradiol and progesterone. Hormonal profiles during the second treated cycle show that preovulatory gonadotropin surge is blunted and that no significant progesterone secretion occurs. Estradiol production is variable up to the middle of the cycle, and then homogeneously low normal. Menstrual cyclicity is respected and ovarian function is restored during the first cycle after treatment disruption. PMID:7511024

Pelissier, C; Blacker, C; Feinstein, M C; Cournot, A; Denis, C

1994-01-01

162

Continuous microcellular foaming of polyvinyl chloride and compatibilization of polyvinyl chloride and polylactide composites  

NASA Astrophysics Data System (ADS)

This dissertation focuses on overcoming existing limitations of WPCs which prevent them from realizing their full market potential. These limitations include: (i) lack of a continuous extrusion process for microcellular foaming of polyvinyl chloride (PVC) and its composites using supercritical fluids to reduce the high density of the WPCs, (ii) need for an efficient coupling agent for WPCs to overcome the poor compatibility between wood and plastic, and (iii) unproven use of wood as a filler for the biopolymer polylactide (PLA) to make "green" composites. These limitations were addressed through experimentation to develop a continuous extrusion process for microcellular foaming, and through surface modification of wood flour using natural coupling agents. The effects of wood flour, acrylic modifier and plasticizer content on the rheological properties of PVC based WPCs were studied using an extrusion capillary rheometer and a two-level factorial design. Wood flour content and acrylic modifier content were the major factors affecting the die swell ratio. Addition of plasticizer decreased the true viscosity of unfilled and filled PVC, irrespective of the acrylic modifier content. However, the addition of acrylic modifier significantly increased the viscosity of unfilled PVC but decreased the composite viscosity. Results of the rheological study were used to set baseline conditions for the continuous extrusion foaming of PVC WPCs using supercritical CO 2. Effects of material composition and processing conditions on the morphology of foamed samples were investigated. Foamed samples were produced using various material compositions and processing conditions, but steady-state conditions could not be obtained for PVC. Thus the relationships could not be determined. Incompatibility between wood flour and PVC was the focus of another study. The natural polymers chitin and chitosan were used as novel coupling agents to improve interfacial adhesion between the polymer matrix and wood fiber. Results indicated that addition of chitin and chitosan significantly increased the flexural properties and storage modulus of PVC WPCs, compared to composites without coupling agent. Significant improvements were attained with 0.5 wt. % chitosan and with 6.67 wt. % chitin. Based on the efficiency of chitosan as a coupling agent for PVC based WPCs, a biodegradable composite using polylactide (PLA) and chitosan was developed. Wood flour (0--40 wt. %) was evaluated as a filler for PLA composites and its effect on mechanical, thermal and chemical properties was studied with and without chitosan (0--10 wt. %). Addition of wood flour significantly increased the flexural and storage moduli of PLA-wood flour composites, but had no effect on glass transition temperature (Tg). Chitosan had no significant effect on any of the properties of the composites studied. Development of an efficient and effective coupling agent for PVC wood composite is a significant development which will increase performance while reducing cost. Wood filled PLA composites can further expand WPCs into applications such as packaging and automotive. Results from these studies have broadened the current knowledge base for WPC products and will be useful in the continued expansion of wood composites technology into a variety of industries.

Shah, Bhavesh

163

Nanodielectric system for cryogenic applications: Barium titanate filled polyvinyl alcohol  

SciTech Connect

In the current study the focus is on dielectric properties (as a function of frequency and temperature) of a polymeric composite system composed of polyvinyl alcohol and barium titanate nano powder. In the investigations, the temperature range is between 50-295 K, and the frequency range is between $20\\ \\hertz-1\\ \\mega\\hertz$. Polarization and conduction processes are investigated in the linear regime. Dielectric breakdown strengths of samples are also reported. The materials presented have potential to be implemented in cryogenic capacitor or field grading applications.

Tuncer, Enis [ORNL; Sauers, Isidor [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL; Duckworth, Robert C [ORNL

2008-01-01

164

Memristive learning and memory functions in polyvinyl alcohol polymer memristors  

NASA Astrophysics Data System (ADS)

Polymer based memristive devices can offer simplicity in fabrication and at the same time promise functionalities for artificial neural applications. In this work, inherent learning and memory functions have been achieved in polymer memristive devices employing Polyvinyl Alcohol. The change in conduction in such polymer devices strongly depends on the pulse amplitude, duration and time interval. Through repetitive stimuli training, temporary short-term memory can transfer into consolidated long-term memory. These behaviors bear remarkable similarities to certain learning and memory functions of biological systems.

Lei, Yan; Liu, Yi; Xia, Yidong; Gao, Xu; Xu, Bo; Wang, Suidong; Yin, Jiang; Liu, Zhiguo

2014-07-01

165

Comparison of storage stability of odorous VOCs in polyester aluminum and polyvinyl fluoride Tedlar® bags.  

PubMed

Whole air sampling using containers such as flexible bags or rigid canisters is commonly used to collect samples of volatile organic compounds (VOC) in air. The objective of this study was to compare the stability of polyester aluminum (PEA) and polyvinyl fluoride (PVF, brand name Tedlar(®)) bags for gaseous VOC sampling. Eight VOC standards (benzene, toluene, p-xylene, styrene, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, and isobutyl alcohol) were placed into each bag at storage times of 0, 2, and 3 days prior to analyses by gas chromatography/mass spectrometry (GC/MS). From each bag representing each storage day, samples of 3 different mass loadings were withdrawn and analyzed to derive response factors (RF) of each chemical between the slope of the GC response (y-axis) vs. loaded mass (x-axis). The relative recoveries (RR) of VOC, if derived by dividing RF value of a given storage day by that of 0 day, varied by time, bag type, and VOC type. If the RR values after three days are compared, those of methyl isobutyl ketone were the highest with 96 (PVF) and 99% (PEA); however, the results of isobutyl alcohol were highly contrasting between the two bags with 31 and 94%, respectively. Differences in RR values between the two bag types increased with storage time, such that RR of PEA bags (88±10%) were superior to those of PVF bags (73±22%) after three days, demonstrating that VOC in PEA bags were more stable than in PVF bags. PMID:22177080

Kim, Yong-Hyun; Kim, Ki-Hyun; Jo, Sang-Hee; Jeon, Eui-Chan; Sohn, Jong Ryeul; Parker, David B

2012-01-27

166

Cross-linked polyvinyl chloride resin foam and method of manufacturing the same  

Microsoft Academic Search

This invention provides a method of continuously manufacturing a cross-linked polyvinyl chloride resin foam sheet which has a low density, uniformly fine cell, excellent thermal moldability and high heat resistance and is neither deformed nor deteriorated even by long storage characterized by uniformly kneading the polyvinyl chloride resin with a blowing agent, stabilizer, plasticizer and cross-linking promoter without causing the

J. Sasajima; K. Mogi; H. Nagai; A. Nojiri; N. Shiina

1984-01-01

167

Polymeric sulfides CdS, CuS, and NiS in polyvinyl alcohol matrix  

NASA Astrophysics Data System (ADS)

Cadmium, copper, and nickel sulfides have been synthesized in a polyvinyl alcohol matrix. The specimens have been investigated by means of vibration spectroscopy and X-ray diffraction analysis. The obtained data have confirmed the formation of cadmium sulfide with a polymeric chain structure in polyvinyl alcohol. The possibility of producing similar materials based on copper and nickel sulfides has been discussed.

Prosanov, I. Yu.; Bulina, N. V.

2014-06-01

168

Preparation and Properties of Biodegradable Polymer Film Based on Polyvinyl Alcohol and Tropical Fruit Waste Flour  

Microsoft Academic Search

In this study, two different types of tropical fruit waste flour, rambutan waste flour (RWF) and banana waste flour (BWF), were blended with polyvinyl alcohol (PVOH) by solution casting method. The structure of the blend film was characterised by Fourier Transform Infrared Spectroscopy. The tensile strength and elongation at break of tropical fruit waste flour-filled polyvinyl alcohol were lower, but

Ooi Xian Zhong; Hanafi Ismail; Nor Aziah Abdul Aziz; Azhar Abu Bakar

2011-01-01

169

Microwave reflectivity measurement of silicon urea polyvinyl alcohol \\/ epoxy resin composites in X and Ku bands  

Microsoft Academic Search

In the paper presented here, a thermally stable epoxy resin modified urea - polyvinyl alcohol - silicon blends have been prepared by in situ polymerization technique. For this, the materials were modified with triethylene tetramine (hardener) to obtain highly cross-linked thermosetting resins. The authors have synthesized the polymer composites; silicon-urea-polyvinyl alcohol in three ratios in weight percentages with analytical reagent

M. Murugan; V. K. Kokate

2009-01-01

170

Sorption of boric acid by hydroxylic sorbents synthesized from polyvinyl alcohol and polyvinylene glycol  

Microsoft Academic Search

It has been shown that sorbents synthesized from polyvinyl alcohol (PVA) and polyvinyl glycol (PVG) are the most effective agents for extraction of boron from natural waters and brines. The action of such sorbents is based on the ability of boric acid to form stable complexes with polyhydroxy compounds. In this work the authors studied hydroxylic sorbents differing in OH-group

G. V. Kiselgof; L. K. Arkhangelskii; N. A. Bochkova

1986-01-01

171

Solute Diffusion in Poly(vinyl alcohol)/Poly(acrylic acid) Interpenetrating Networks  

E-print Network

Solute Diffusion in Poly(vinyl alcohol)/Poly(acrylic acid) Interpenetrating Networks Nikolaos A contained within the hydrogel at equilibrium; it is a function of the network structure, cross-linking ratio studied such interactions using well- characterized interpenetrating networks of poly(vinyl alcohol) (PVA

Peppas, Nicholas A.

172

CORROSION OF LEAD SHIELDING IN NUCLEAR MATERIALS PACKAGES  

SciTech Connect

Inspection of United States-Department of Energy (US-DOE) model 9975 nuclear materials shipping package revealed corrosion of the lead shielding induced by off-gas constituents from organic components in the package. Experiments were performed to determine the corrosion rate of lead when exposed to off-gas or degradation products of these organic materials. The results showed that the room temperature vulcanizing (RTV) sealant was the most corrosive organic species followed by the polyvinyl acetate (PVAc) glue. The fiberboard material induced corrosion to a much lesser extent than the PVAc glue and RTV, and only in the presence of condensed water. The results indicated faster corrosion at temperatures higher than ambient and with condensed water as expected. A corrosion rate of 0.05 mm/year measured for coupons exposed to the most aggressive conditions was recommended as a conservative estimate for use in package performance calculations.

Subramanian, K; Kerry Dunn, K

2007-11-16

173

CORROSION OF LEAD SHIELDING IN NUCLEAR MATERIALS PACKAGES  

SciTech Connect

Inspection of United States-Department of Energy (US-DOE) model 9975 nuclear materials shipping package revealed corrosion of the lead shielding that was induced by off-gas constituents from organic components in the package. Experiments were performed to determine the corrosion rate of lead when exposed to off-gas or degradation products of these organic materials. The results showed that the room temperature vulcanizing (RTV) sealant was the most corrosive organic species used in the construction of the packaging, followed by polyvinyl acetate (PVAc) glue. Fiberboard material, also used in the construction of the packaging induced corrosion to a much lesser extent than the PVAc glue and RTV sealant, and only in the presence of condensed water. The results indicated faster corrosion at temperatures higher than ambient and with condensed water. In light of these corrosion mechanisms, the lead shielding was sheathed in a stainless steel liner to mitigate against corrosion.

Subramanian, K; Kerry Dunn, K; Joseph Murphy, J

2008-07-18

174

Enzymatic production of glycerol acetate from glycerol.  

PubMed

In this study, we report the enzymatic production of glycerol acetate from glycerol and methyl acetate. Lipases are essential for the catalysis of this reaction. To find the optimum conditions for glycerol acetate production, sequential experiments were designed. Type of lipase, lipase concentration, molar ratio of reactants, reaction temperature and solvents were investigated for the optimum conversion of glycerol to glycerol acetate. As the result of lipase screening, Novozym 435 (Immobilized Candida antarctica lipase B) was turned out to be the optimal lipase for the reaction. Under the optimal conditions (2.5 g/L of Novozym 435, 1:40 molar ratio of glycerol to methyl acetate, 40 °C and tert-butanol as the solvent), glycerol acetate production was achieved in 95.00% conversion. PMID:25640720

Oh, Seokhyeon; Park, Chulhwan

2015-02-01

175

Preparation and application of low molecular weight poly(vinyl chloride). III mechanical properties of blended poly(vinyl chloride)  

SciTech Connect

The blending effect of poly(vinyl chloride) with relatively higher molecular weight (HMW-PVC) and relatively lower molecular weight (LMW-PVC) has been investigated by measuring various mechanical properties: melt properties, tensile strength, tensile modulus, and impact strength. The blended PVC has slightly improved melt properties in comparison with the HMW-PVC used. The tensile strength of the blended PVC is related to the weight-average polymerization degree (Pw) of LMW-PVC and the LMW-PVC content. At the LMW-PVC content of 20%, the tensile strength of blended PVC is a maximum: approximately 58 MPa.

Yamamoto, Kikuo; Maehala, Takashi; Mitani, Katsuo; Mizutani, Yukio (Tokuyama Soda Co., Ltd., Tokuyama-city (Japan))

1993-11-05

176

Acetate kinase: a triple-displacement enzyme.  

PubMed

Facts relating to the mechanism of phosphoryl transfer by acetate kinase (ATP:acetate phosphotransferase, EC 2.7.2.1) are reviewed. They point to the existence of at least one experimentally established phosphoenzyme (E-P) intermediate on the reaction pathway. Sterically, the phosphoryl transfer occurs with a net inversion of the configuration of the phosphorus atom. These facts are best in accord with a triple-displacement mode of action for acetate kinase, with two E-P intermediates and three steric inversions on phosphorus. It follows that a second E-P for acetate kinase must exist. PMID:6248856

Spector, L B

1980-05-01

177

Contact dermatitis induced by glatiramer acetate.  

PubMed

Glatiramer acetate (Copaxone(®)) is an immunomodulatory polypeptide used in patients with relapsing-remitting multiple sclerosis. It represents a safe treatment option with mild side effects. In this study, we look at a 39-year-old woman who received glatiramer acetate as subcutaneous injections for two months and developed contact dermatitis. The drug had to be stopped, and treatment with topical prednisone was initiated. Prick/scratch testing was negative but the lymphocyte transformation test was highly positive for glatiramer acetate. This is the first report on contact dermatitis induced by glatiramer acetate injections. The treatment consisted of local topical steroids and cessation of the drug. PMID:21729979

Haltmeier, S; Yildiz, M; Müller, S; Anliker, M D; Heinzerling, L

2011-11-01

178

Cross-linked polyvinyl alcohol and method of making same  

SciTech Connect

A film-forming polyvinyl alcohol polymer is mixed with a polyaldehyde-polysaccharide cross-linking agent having at least two monosaccharide units and a plurality of aldehyde groups per molecule, preferably an average of at least one aldehyde group per monosaccharide units. The cross-linking agent, such as a polydialdehyde starch, is used in an amount of about 2.5 to 20% of the theoretical amount required to cross-link all of the available hydroxyl groups of the polyvinyl alcohol polymer. Reaction between the polymer and cross-linking agent is effected in aqueous acidic solution to produce the cross-linked polymer. The polymer product has low electrical resistivity and other properties rendering it suitable for making separators for alkaline batteries. In that event, the mixture of polymer and cross-linking agent is formed into a sheet or film or the like and the film is cut to size and otherwise fabricated into a configuration suitable for a particular end use. The crosslinking reaction is then carried out to produce the final product.

Hsu, L.; Philipp, W.H.; Sheibley, D.W.

1981-06-09

179

New insight into modified release pellets - Internal structure and drug release mechanism.  

PubMed

The aim of the study was to explore the drug release mechanism from pellets, coated with blends of poly(vinyl acetate) (PVAc) and polyvinyl alcohol-polyethylene glycol graft copolymer (PVA-PEG). Water influx and drug solubilization inside the pellets were investigated in correlation to drug release. The highly soluble drug Chlorpheniramine maleate (CPM) was used as a model compound. Modified release pellets were manufactured by fluid bed drug layering and film coating of starter beads. The pellets were characterized using cross section EDX mapping, confirming location and homogeneity of the different layers. A film coat of 23%, containing PVAc/PVA-PEG in 9:1 ratio, resulted in a sigmoid shaped release curve with 2 h lag-time, followed by 3 h of continuous drug release. Using NMR analysis, water influx and drug solubilization inside the pellets were detected within 20 min. Additionally, dissolution of PVA-PEG after several minutes and drug release after the lag-time were measurable. A fast water influx into PVAc/PVA-PEG film coated pellets did not result in a fast drug release. Despite a fast drug solubilization within the pellets, drug release was initiated after 2 h, suggesting a one way stream of water during the observed lag-time. PMID:18433911

Ensslin, Simon; Moll, Klaus Peter; Paulus, Kurt; Mäder, Karsten

2008-06-01

180

Soluplus Graft Copolymer: Potential Novel Carrier Polymer in Electrospinning of Nanofibrous Drug Delivery Systems for Wound Therapy  

PubMed Central

Electrospinning is an effective method in preparing polymeric nanofibrous drug delivery systems (DDSs) for topical wound healing and skin burn therapy applications. The aim of the present study was to investigate a new synthetic graft copolymer (Soluplus) as a hydrophilic carrier polymer in electrospinning of nanofibrous DDSs. Soluplus (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (PCL-PVAc-PEG)) was applied in the nonwoven nanomats loaded with piroxicam (PRX) as a poorly water-soluble drug. Raman spectroscopy, X-ray powder diffraction, differential scanning calorimetry, and scanning electron microscopy (SEM) were used in the physical characterization of nanofibrous DDSs. According to the SEM results, the drug-loaded PCL-PVAc-PEG nanofibers were circular in cross-section with an average diameter ranging from 500?nm up to 2?µm. Electrospinning stabilized the amorphous state of PRX. In addition, consistent and sustained-release profile was achieved with the present nanofibrous DDSs at the physiologically relevant temperature and pH applicable in wound healing therapy. In conclusion, electrospinning can be used to prepare nanofibrous DDSs of PCL-PVAc-PEG graft copolymer (Soluplus) and to stabilize the amorphous state of a poorly water-soluble PRX. The use of this synthetic graft copolymer can open new options to formulate nanofibrous DDSs for wound healing. PMID:24575414

Tamm, Ingrid; Laidmäe, Ivo; Lust, Andres; Kirsimäe, Kalle

2014-01-01

181

Utilizing Matrix-Filler Interactions in the Design of Stimuli-Responsive, Mechanically-Adaptive Electrospun Composites  

NASA Astrophysics Data System (ADS)

A new class of all-organic, stimuli-responsive and mechanically-adaptive electrospun nanocomposites, which have the ability to alter their stiffness upon hydration, were developed. These materials were fabricated by incorporating an electrospun mat of poly(vinyl alcohol) (PVA) as the filler in a polymeric matrix consisting of either poly(vinyl acetate) (PVAc) or ethylene oxide-epicholorohydrin copolymer (EO-EPI). The incorporation of high stiffness, high aspect ratio PVA filler mat significantly enhanced the tensile storage modulus of EO-EPI based composites, while modulus enhancement was only noticed above the glass transition for PVAc-based composites. Composite materials based on a rubbery EO-EPI host polymer and PVA filler exhibit an irreversible reduction by a factor of 12 of the tensile modulus upon hydration. In contrast, composites comprised of PVAc show a reversible reduction of modulus by a factor of 280 upon water uptake. The mechanical morphing of the electrospun composites is the result of the filler crystallinity, and matrix-filler interactions facilitated by the surface hydroxyl groups of the PVA filler. The choice of polymer matrix and electrospun nanofiber fillers allow control of matrix-filler interactions in a new series of all-organic composites to achieve desired stimuli-responsiveness and mechanical-adaptability upon exposure to various stimuli.

Wanasekara, Nandula; Stone, David; Wnek, Gary; Korley, Lashanda

2013-03-01

182

Positron scattering from vinyl acetate  

NASA Astrophysics Data System (ADS)

Using a Beer-Lambert attenuation approach, we report measured total cross sections (TCSs) for positron scattering from vinyl acetate (C4H6O2) in the incident positron energy range 0.15-50 eV. In addition, we also report an independent atom model with screening corrected additivity rule computation results for the TCSs, differential and integral elastic cross sections, the positronium formation cross section and inelastic integral cross sections. The energy range of these calculations is 1-1000 eV. While there is a reasonable qualitative correspondence between measurement and calculation for the TCSs, in terms of the energy dependence of those cross sections, the theory was found to be a factor of ˜2 larger in magnitude at the lower energies, even after the measured data were corrected for the forward angle scattering effect.

Chiari, L.; Zecca, A.; Blanco, F.; García, G.; Brunger, M. J.

2014-09-01

183

Fluctuation Dissipation Relation in stuctural and polymeric glasses  

NASA Astrophysics Data System (ADS)

We present results from ongoing experimental studies to probe deviations from the fluctuation dissipation relation in supercooled liquids and glasses following a thermal quench. Small deviations have been theoretically predicted (Cugliandolo et. al.) and seen in some systems like glycerol and in a colloidal system like laponite. We present results on glycerol and PolyvinylAcetate(PVac),probing the dielectric and viscoelastic relaxation respectively. We also present some experimental results to see if thermal history has any effect on the response function like dielectric susceptibility as these response functions are used in calculating deviations from the fluctuation deviation relation.

Mukhopadhyay, Shomeek; Israeloff, Nathan

2002-03-01

184

Manufacturing Ethyl Acetate From Fermentation Ethanol  

NASA Technical Reports Server (NTRS)

Conceptual process uses dilute product of fermentation instead of concentrated ethanol. Low-concentration ethanol, extracted by vacuum from fermentation tank, and acetic acid constitutes feedstock for catalytic reaction. Product of reaction goes through steps that increases ethyl acetate content to 93 percent by weight. To conserve energy, heat exchangers recycle waste heat to preheat process streams at various points.

Rohatgi, Naresh K.; Ingham, John D.

1991-01-01

185

Biodegradable Plastics Based on Cellulose Acetate  

Microsoft Academic Search

It is generally known that secondary cellulose acetate (with 53 to 56% acetyl groups) is suitable for thermoplastic processing. With appropriate plasticizers a plastic material is obtained which excels in transparency and pleasant texture, and it is therefore often used for tool handles, combs, spectacle frames, and the like. In principle, cellulose acetate with such a degree of substitution is

Alexander Ach

1993-01-01

186

X-ray analysis of poly(vinyl fluoride)  

SciTech Connect

Three different X-ray analysis technique were used to investigate the chain defect content present in the crystalline regions of poly(vinyl fluoride). The techniques used were a fiber pattern analysis, a powder pattern analysis, and a meridional intensity analysis. The fiber pattern analysis proved unable to determine either the tacticity or regic defect content in PVF. However, it was found that the refinement favored a statistical packing of the chains in the crystalline regions. This packing arrangement was supported by the powder pattern analysis and molecular modeling calculations. The meridional intensity analysis proved to be sensitive to the regic defect content of the sample. The results of this analysis correlated well with previous DSC work.

Lando, J.B. [Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Macromolecular Science; Hanes, M.D. [Phillips Petroleum, Bartlesville, OK (United States)

1995-02-13

187

Vitrification of Polyvinyl Chloride Waste from Korean Nuclear Power Plants  

SciTech Connect

Vitrification is considered as an economical and safe treatment technology for low-level radioactive waste (LLW) generated from nuclear power plants (NPPs). Korea is in the process of preparing for its first ever vitrification plant to handle LLW from its NPPs. Polyvinyl chloride (PVC) has the largest volume of dry active wastes and is the main waste stream to treat. Glass formulation development for PVC waste is the focus of study. The minimum additive waste stabilization approach has been utilized in vitrification. It was found that glasses can incorporate a high content of PVC ash (up to 50 wt%), which results in a large volume reduction. A glass frit, KEP-A, was developed to vitrify PVC waste after the optimization of waste loading, melt viscosity, melting temperature, and chemical durability. The KEP-A could satisfactorily vitrify PVC with a waste loading of 30 to 50 wt%. The PVC-frit was tolerant of variations in waste composition.

Sheng, Jiawei [Kyoto University (Japan); Choi, Kwansik [Nuclear Environment Technology Institute (Korea, Republic of); Yang, Kyung-Hwa [Nuclear Environment Technology Institute (Korea, Republic of); Lee, Myung-Chan [Nuclear Environment Technology Institute (Korea, Republic of); Song, Myung-Jae [Nuclear Environment Technology Institute (Korea, Republic of)

2000-02-15

188

Cross-linked polyvinyl alcohol films as alkaline battery separators  

NASA Technical Reports Server (NTRS)

Cross-linking methods were investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: (1) PVA-dialdehyde blends post-treated with an acid or acid periodate solution (two-step method) and (2) PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid functionality (one-step method). Laboratory samples of each cross-linked type of film were prepared and evaluated in standard separator screening tests. The pilot-plant batches of films were prepared and compared to measure differences due to the cross-linking method. The pilot-plant materials were then tested in nickel oxide - zinc cells to compare the two methods with respect to performance characteristics and cycle life. Cell test results are compared with those from tests with Celgard.

Sheibley, D. W.; Manzo, M. A.; Gonzalez-Sanabria, O. D.

1982-01-01

189

Polyvinyl alcohol coating of polystyrene inertial confinement fusion targets  

NASA Technical Reports Server (NTRS)

An inertial confinement fusion (ICF) target made of polystyrene is first levitated in an acoustic field. The surface of the target is then etched using an appropriate solution (e.g., cyclohexane) to enhance the wetting characteristics. A specially prepared polyvinyl alcohol solution is atomized using an acoustic atomizer and deposited on the surface of the target. The solution is air dried to form a thin coating (2 microns) on the target (outside diameter of about 350-850 microns). Thicker coatings are obtained by repeated applications of the coating solutions. Preliminary results indicate that uniform coatings may be achievable on the targets with a background surface smoothness in the order of 1000 A.

Annamalai, P.; Lee, M. C.; Crawley, R. L.; Downs, R. L.

1985-01-01

190

Cross-linked polyvinyl alcohol films as alkaline battery separators  

NASA Technical Reports Server (NTRS)

Cross-linking methods have been investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: (1) PVA-dialdehyde blends post-treated with an acid or acid periodate solution (two-step method) and (2) PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid functionality (one-step method). Laboratory samples of each cross-linked type of film were prepared and evaluated in standard separator screening tests. Then pilot-plant batches of films were prepared and compared to measure differences due to the cross-linking method. The pilot-plant materials were then tested in nickel oxide-zinc cells to compare the two methods with respect to performance characteristics and cycle life. Cell test results are compared with those from tests with Celgard.

Sheibley, D. W.; Manzo, M. A.; Gonzalez-Sanabria, O. D.

1983-01-01

191

Biodegradable thermoplastic composites based on polyvinyl alcohol and algae.  

PubMed

Algae constitute a largely available, low value material from renewable resources of marine origin to be used for the production of eco-compatible composites. Fibers of the green alga Ulva armoricana from the French coast were positively evaluated for the production of composites with a hydrophilic, eco-compatible polymer, such as poly(vinyl alcohol) (PVA) as continuous matrix by casting of aqueous suspensions and compression molding. PVA, Ulva, and starch were also successfully processed by the melt in the presence of glycerol. Positive results were obtained for film-forming properties and mechanical characteristics also with limited amounts of PVA (40%) attesting for Ulva suitability to be introduced in composites (up to 30%). Degradation in soil of Ulva and an Ulva-based composites outlined a rapid mineralization of Ulva in the selected medium (over 80% in 100 days) while the composite samples underwent a mineralization rate affected by the different component propensity to degradation. PMID:18257530

Chiellini, Emo; Cinelli, Patrizia; Ilieva, Vassilka I; Martera, Martina

2008-03-01

192

Cross-linked polyvinyl alcohol films as alkaline battery separators  

SciTech Connect

Cross-linking methods were investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: (1) PVA-dialdehyde blends post-treated with an acid or acid periodate solution (two-step method) and (2) PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid functionality (one-step method). Laboratory samples of each cross-linked type of film were prepared and evaluated in standard separator screening tests. The pilot-plant batches of films were prepared and compared to measure differences due to the cross-linking method. The pilot-plant materials were then tested in nickel oxide - zinc cells to compare the two methods with respect to performance characteristics and cycle life. Cell test results are compared with those from tests with Celgard.

Sheibley, D.W.; Manzo, M.A.; Gonzalez-Sanabria, O.D.

1982-03-01

193

Cross-linked polyvinyl alcohol films as alkaline battery separators  

SciTech Connect

Cross-linking methods have been investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: PVA-dialdehyde blends post-treated with an acid or acid periodate solution and PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid functionality. Laboratory samples of each cross-linked type of film were prepared and evaluated in standard separator screening tests. Then pilotplant batches of films were prepared and compared to measure differences due to the cross-linking method. The pilot-plant materials were then tested in nickel oxide-zinc cells to compare the two methods with respect to performance characteristics and cycle life. Cell test results are compared with those from tests with Celgard.

Sheibley, D.W.; Gonzalez-Sanabria, O.D.; Manzo, M.A.

1983-02-01

194

Growth characteristics of selected fungi on polyvinyl film  

SciTech Connect

The objective of this study was to determine if plasticized polyvinyl chloride film would support the growth of any of nine species of fungi. The film was suspended in distilled water with no nutrients or with glucose or ammonium sulfate. Spores of each of the test species were inoculated into the suspension medium, and the mixture was incubated at 30/sup 0/C for up to 18 weeks. Most species were found to be capable of utilizing the film for carbon or nitrogen when the other nutrient was supplied. Only two species, Aspergillus fischeri and Paecilomyces sp., were found to be capable of utilizing components of the film without added nutrients. Components of the polyvinyl chloride film were then incorporated into mineral salts medium to determine if these components could serve as carbon sources in the presence of ammonium nitrate. The only component found to be utilized by all the fungi as a carbon source was epoxidized oil, a plasticizer-stabilizer. Calcium-zinc stearate was an available carbon source for all except the Penicillium and Verticillium strains. The only other component utilized was a stearamide, which was metabolized solely by the Aspergillus sp. Only the stearamide contained enough nitrogen to serve as a primary source in the film. The compound, however, did not support growth of fungi in the presence of glucose. It was theorized that either the nitrogen of the stearamide was more readily available to the fungi in the whole film due to the presence of trace nutrients or the nitrogen was supplied by exogenous sources.

Roberts, W.T.; Davidson, P.M.

1986-04-01

195

An experimental study for syndiotactic polyvinyl alcohol spheres as an embolic agent: can it maintain spherical shape in vivo?  

PubMed

Syndiotactic polyvinyl alcohol (PVA) had been developed to overcome the drawbacks of atactic PVA spheres that deform easily, which can lead to non-target embolization. This study was performed to evaluate the in vivo stability of spherical shape of the syndiotactic PVA spheres. Selective arteriography and transarterial embolization (TAE) were performed in the main renal arteries of eight New Zealand white rabbits using syndiotactic PVA sphere that consisted of syndiotactic PVA skin and a copolymer core of vinyl acetate/vinyl pivalate. The size of the syndiotactic PVA spheres used for the TAE was 212-355 ?m. The rabbits were sacrificed 12-14 days after TAE. Gross and microscopic examinations of each kidney were performed. The microscopic examination showed infarction of all embolized kidneys. Syndiotactic PVA spheres were seen uniformly within the arterial lumen and appeared as round ring-like structures without any deformity. The syndiotactic PVA spheres exclusively occupied the arterial lumen. As a conclusion, syndiotactic PVA spheres maintained their spherical shape without significant deformation in this in vivo short-term experimental study. Further investigation is necessary for evaluation of detailed effects of physical stability in tumor embolization. PMID:24948458

Chun, Ho Jong; Lee, Hae Giu; Lyoo, Won Seok; Lee, Ji Youl; Kim, Jina

2014-01-01

196

Covalently attached, silver-doped poly(vinyl alcohol) hydrogel films on poly(l-lactic acid).  

PubMed

Covalently attached, soft poly(vinyl alcohol) (PVA) hydrogel films containing silver particles were prepared on solid biodegradable poly(l-lactic acid) (PLLA) samples by a multistep procedure involving oxygen plasma treatment, UV-initiated graft polymerization, and chemical grafting methods. The modification steps were followed and verified using attenuated total reflection infrared spectroscopy and X-ray photoelectron spectroscopy. 2-Hydroxyethyl methacrylate (HEMA) was graft polymerized from the surface of oxygen plasma-treated PLLA film samples and the alcohol functionality in the grafted polyHEMA chains was oxidized using pyridinium dichromate to obtain an aldehyde-rich surface. PVA was then grafted onto this surface using acid catalysis (acetal formation). The "freeze/thaw method" was used to form a PVA hydrogel layer that incorporated the covalently grafted PVA chains in the physically cross-linked gel. This composite film (PLLA-PVA(gel)) was doped with silver ions, which were reduced to silver using NaBH(4). Scanning electron microscopy of cross sections of PLLA-PVA(gel) indicates robust attachment of the PVA hydrogel layer to the PLLA film. PLLA-PVA(gel/Ag(0)) film samples exhibit both antibacterial and reduced cell adhesion properties due to the antibacterial properties of silver nanoparticles and high water content, respectively. This method provides a route to mechanically sound biodegradable materials with tunable soft material surface properties. Potential applications in tissue engineering and biomedical devices are envisioned. PMID:20307097

Zan, Xingjie; Kozlov, Mikhail; McCarthy, Thomas J; Su, Zhaohui

2010-04-12

197

Roles of tryptophan residue and disulfide bond in the variable lid region of oxidized polyvinyl alcohol hydrolase.  

PubMed

Oxidized polyvinyl alcohol hydrolase (OPH) catalyzes the cleavage of C-C bond in ?-diketone. It belongs to the ?/?-hydrolase family and contains a unique lid region that covers the active site. The lid is the most variable region when pOPH from Pseudomonas sp. VM15C and sOPH from Sphingopyxis sp. 113P3 are compared. The wild-type enzymes and the pOPH mutants W255A, W255Y and W255F were analyzed for lipase activity by using p-nitrophenyl (pNP) esters as the substrates. The wild-type enzymes showed increased Km and decreased kcat/Km with the acyl chain length, and the mutants showed reduced kcat/Km for pNP acetate, indicating the importance of Trp255 in sequestering the active site from solvent. The significantly lower activity for pNP butyrate can be a result of product inhibition, as suggested by the complex crystal structures, in which butyric acid, DMSO or PEG occupied the same substrate-binding cleft. The mutant activity was retained with pNP caprylate and pNP laurate as the substrates, reflecting the amphipathic nature of the cleft. Moreover, the disulfide bond formation of Cys257/267 is important for the activity of pOPH, but it is not essential for sOPH, which has a shorter lid structure. PMID:25173935

Yang, Yu; Ko, Tzu-Ping; Liu, Long; Li, Jianghua; Huang, Chun-Hsiang; Chen, Jian; Guo, Rey-Ting; Du, Guocheng

2014-09-26

198

Emulsion polymerization of vinyl acetate: safe optimization of a hazardous complex process.  

PubMed

Fast and exothermic discontinuous emulsion polymerization processes are particularly difficult to optimize from both safety and productivity point of view because of the occurrence of side undesired reactions (e.g. chain transfer to monomer, backbiting, propagation of tertiary radicals, termination by disproportion, etc.) and the hazards of boiling phenomena and stable foam formation under atmospheric pressure. Moreover, the relevant number of loading, heating and cooling steps, required before starting the monomer addition (that is, the desired reaction), makes a strict product quality reproducibility very difficult to obtain. Under these operating conditions, it is necessary to employ a suitable combined theoretical and experimental procedure able to detect the optimum process dosing time at both the laboratory and the industrial scale. In this work, it is shown how to use the topological criterion theory together with proper adiabatic calorimeter and RC1 experimental data to safely optimize the synthesis of polyvinyl acetate through the radical emulsion polymerization of vinyl acetate by the means of an indirectly cooled isoperibolic semibatch reactor. PMID:21632179

Copelli, S; Derudi, M; Sempere, J; Serra, E; Lunghi, A; Pasturenzi, C; Rota, R

2011-08-15

199

Ulipristal acetate in emergency contraception.  

PubMed

Despite the widespread availability of highly effective methods of contraception, unintended pregnancy is common. Unplanned pregnancies have been linked to a range of health, social and economic consequences. Emergency contraception reduces risk of pregnancy after unprotected intercourse, and represents an opportunity to decrease number of unplanned pregnancies and abortions. Emergency contraception pills (ECP) prevent pregnancy by delaying or inhibiting ovulation, without interfering with post fertilization events. If pregnancy has already occurred, ECPs will not be effective, therefore ECPs are not abortificants. Ulipristal acetate (17alpha-acetoxy-11beta-(4N-N,N-dymethilaminophenyl)-19-norpregna--4,9-diene-3,20-dione) is the first drug that was specifically developed and licensed for use as an emergency contraceptive. It is an orally active, synthetic, selective progesterone modulator that acts by binding with high affinity to the human progesterone receptor where it has both antagonist and partial agonist effects. It is a new molecular entity and the first compound in a new pharmacological class defined by the pristal stem. Up on the superior clinical efficacy evidence, UPA has been quickly recognized as the most effective emergency contraceptive pill, and recently recommended as the first prescription choice for all women regardless of the age and timing after intercourse. This article provides literature review of UPA and its role in emergency contraception. PMID:24851646

Goldstajn, Marina Sprem; Baldani, Dinka Pavici?; Skrgati?, Lana; Radakovi?, Branko; Vrbi?, Hrvoje; Cani?, Tomislav

2014-03-01

200

Vesicles protect activated acetic acid.  

PubMed

Abstract Methyl thioacetate, or activated acetic acid, has been proposed to be central to the origin of life and an important energy currency molecule in early cellular evolution. We have investigated the hydrolysis of methyl thioacetate under various conditions. Its uncatalyzed rate of hydrolysis is about 3 orders of magnitude faster (K=0.00663 s(-1); 100°C, pH 7.5, concentration=0.33 mM) than published rates for its catalyzed production, making it unlikely to accumulate under prebiotic conditions. However, our experiments showed that methyl thioacetate was protected from hydrolysis when inside its own hydrophobic droplets. Further, we found that methyl thioacetate protection from hydrolysis was also possible in droplets of hexane and in the membranes of nonanoic acid vesicles. Thus, the hydrophobic regions of prebiotic vesicles and early cell membranes could have offered a refuge for this energetic molecule, increasing its lifetime in close proximity to the reactions for which it would be needed. This model of early energy storage evokes an additional critical function for the earliest cell membranes. PMID:25280019

Todd, Zoe R; House, Christopher H

2014-10-01

201

Application of lipase immobilized on the biocompatible ternary blend polymer matrix for synthesis of citronellyl acetate in non-aqueous media: kinetic modelling study.  

PubMed

This work reports the use of new support for immobilization of lipase Burkholderia cepacia (BCL) matrix made up of polylactic acid (PLA), chitosan (CH), and polyvinyl alcohol (PVA). Initially lipase from various microbial sources and immobilization support composition was screened to obtain a robust biocatalyst. Among various biocatalysts preparation, the PLA:PVA:CH:BCL (1:6:1:2) was worked as a robust biocatalyst for the citronellyl acetate synthesis. Various reaction parameters were studied in detail to obtain the suitable reaction conditions for model citronellyl acetate synthesis reaction. Various kinetic parameters such as r(max), K(i(citronellol)), K(m(citronellol)), K(m(vinyl acetate)) were determined using non-linear regression analysis for the ternary complex as well as bi-bi ping-pong mechanism. The experimental results and kinetic study showed that citronellyl acetate synthesis catalyzed by immobilized lipase BCL followed the ternary complex mechanism with inhibition by alcohol (citronellol). The energy of activation for citronellyl acetate synthesis was found to be lower for immobilized lipase (8.9 kcal/mol) than aggregated lipase (14.8 kcal/mol) enzyme. The developed biocatalyst showed four to fivefold higher catalytic activity and excellent recyclability (up to six cycles) than the aggregated lipase. PMID:24629263

Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

2014-04-10

202

21 CFR 582.5933 - Vitamin A acetate.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

2013-04-01

203

21 CFR 582.5933 - Vitamin A acetate.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

2011-04-01

204

21 CFR 582.5933 - Vitamin A acetate.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

2012-04-01

205

21 CFR 582.5933 - Vitamin A acetate.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

2010-04-01

206

21 CFR 582.5933 - Vitamin A acetate.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

2014-04-01

207

21 CFR 522.1881 - Sterile prednisolone acetate aqueous suspension.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 false Sterile prednisolone acetate aqueous suspension. 522...ANIMAL DRUGS § 522.1881 Sterile prednisolone acetate aqueous suspension. (a...suspension contains 25 milligrams of prednisolone acetate. (b) Sponsor . See...

2010-04-01

208

Viscosity of Mixtures of ?-Tocopherol Acetate + Mesitylene  

NASA Astrophysics Data System (ADS)

The paper presents results of the share viscosity measurements performed as a function of temperature and concentration for mixtures of ?-tocopherol acetate (vitamine E acetate) and mesitylene, two liquids of essentially different viscosity (four order of magnitude difference at 280 K). The viscosity/ temperature dependence for pure ?-tocopherol acetate as well as for the mixtures studied can be well described with the Vogel-Fulcher-Tammann equation. The viscosities of the mixtures exhibit a strong negative deviation from the rule of additive dependence on concentration and for increasing temperature the maximum value of the deviation shows an exponential decreasing.

Szwajczaka, El?bieta; Stagraczy?ski, Ryszard; Herba, Henryk; ?wiergielb, Jolanta; Jad?yn, Jan

2009-08-01

209

Hydrogen-bonded layer-by-layer assembly of poly(vinyl alcohol) and tannic acid  

E-print Network

Hydrogen-bonded multilayer thin films containing tannic acid (TA) and poly(vinyl alcohol) (PVA) were assembled under different pH conditions, and film growth and dissolution behavior was assessed through profilometry. ...

Sample, Caitlin (Caitlin Sarah)

2014-01-01

210

Structural studies of alumina pillared hectorite using polyvinyl alcohol as a pillaring agent  

E-print Network

In the present work, the structures of a natural hectorite clay pillared with alumina were studied. Frequently, polyvinyl alcohol (PVA) was added as a pillaring agent to observe structural differences in the calcined products. Series of products...

Kroenig, Andrea N

1997-01-01

211

The pharmacology of nomegestrol acetate.  

PubMed

Nomegestrol acetate (NOMAC) is a 19-norprogesterone derivative with high biological activity at the progesterone receptor, a weak anti-androgenic effect, but with no binding to estrogen, glucocorticoid or mineralocorticoid receptors. At dosages of 1.5mg/day or more, NOMAC effectively suppresses gonadotropic activity and ovulation in women of reproductive age. Hemostasis, lipids and carbohydrate metabolism remain largely unchanged. In normal and cancerous human breast cells, NOMAC has shown favorable effects on estrogen metabolism. Like natural progesterone (but in contrast to some other synthetic progestogens), it does not appear stimulate the proliferation of cancerous breast cells. While there has been some experience of the use of NOMAC in combination with estrogens as a hormone replacement therapy, most of the data on the compound are reported in the context of its inclusion as a component of a new contraceptive pill comprising 2.5mg NOMAC combined with 1.5mg estradiol. Because of its strong endometrial efficacy, and due to its high antigonadotropic activity and long elimination half-life (about 50h), the contraceptive efficacy of the new pill is maintained even when dosages are missed. Furthermore, for the first time with a monophasic 24/4 regimen containing estradiol, cyclical stability can be achieved comparable with that obtained using pills containing ethinyl estradiol and progestogens like levonorgestrel or drospirenone. The addition of NOMAC to estradiol means that the beneficial effects of estrogen are not lost, which is of especial importance in relation to the cardiovascular system. On the basis both of its pharmacology and of studies performed during the development of the NOMAC/estradiol pill, involving some 4000 women in total, good long-term tolerability can be expected for NOMAC, although its safety profile is still to be fully ascertained, as the clinical endpoint studies are yet to be completed. PMID:22364709

Ruan, Xiangyan; Seeger, Harald; Mueck, Alfred O

2012-04-01

212

Poly(vinyl chloride) (PVC) hollow fiber ultrafiltration membranes prepared from PVC\\/additives\\/solvent  

Microsoft Academic Search

Using poly(vinyl pyrrolidone) (PVP 40,000) or poly(ethylene glycol) (PEG) with different molecular weights (PEG 600, PEG 800, PEG 1000) as additives and N,N-dimethylacetamide (DMAc) as a solvent, asymmetric poly(vinyl chloride) (PVC) hollow fiber ultrafiltration membranes were prepared by phase inversion technique from 14 to 20wt.% solids including PVC and additives. The 95\\/5 DMAc\\/water and pure water were used as the

Jian Xu; Zhen-Liang Xu

2002-01-01

213

Carboxymethylcellulose and poly(vinyl alcohol) used as a film support for lipases immobilization  

Microsoft Academic Search

Lipases from 10 different sources were immobilized on poly(vinyl alcohol) (PVA), carboxymethycellulose (CMC) and poly(vinyl alcohol):carboxymethycellulose blend (50:50% m\\/m) and used as biocatalysts in esterification reactions of carboxylic acids with n-pentanol in organic media. Among the tested lipases, higher yields in n-pentyl laurate were obtained when lipases from Mucor javanicus (MJL) or Rhyzopus oryzae (ROL) were immobilized in CMC, PVA

Roberto Dalla-Vecchia; Damianni Sebrão; Maria da Graça Nascimento; Valdir Soldi

2005-01-01

214

Semi-interpenetrating polymer networks based on polyaniline and polyvinyl alcohol–glutaraldehyde  

Microsoft Academic Search

A new semi-Interpenetrating Polymer Network (semi-IPN) based on polyvinyl alcohol–glutaraldehyde\\/polyaniline was synthesized and characterized by spectroscopic analysis in the UV–Visible–Infrared region and by scanning electron microscopy (SEM). The semi-IPNs exhibit good mechanical properties, characteristic of polyvinyl alcohol–glutaraldehyde polymer network, and excellent optical properties. The UV–Visible results show that the optical properties of the semi-IPNs are characteristic only of polyaniline polymer,

W. M de Azevedo; J. M de Souza; J. V de Melo

1999-01-01

215

Electrospinning and characterization of medium-molecular-weight poly(vinyl alcohol)\\/high-molecular-weight poly(vinyl alcohol)\\/montmorillonite nanofibers  

Microsoft Academic Search

Submicron fibers of medium-molecular-weight poly(vinyl alcohol) (MMW-PVA), high-molecular-weight poly(vinyl alcohol) (HMW-PVA),\\u000a and montmorillonite clay (MMT) in aqueous solutions were prepared by electrospinning technique. The effect of HMW-PVA and\\u000a MMT on the morphology and mechanical properties of the MMW-PVA\\/HMW-PVA\\/MMT nanofibers were investigated for the first time.\\u000a Scanning electron microscopy, viscometer, tensile strength testing machine, thermal gravimetric analyzer (TGA), and transmission\\u000a electron

Hyun Mi Ji; Hyun Woo Lee; Mohammad Rezaul Karim; In Woo Cheong; Eun A. Bae; Tae Hun Kim; Byung Chul Ji; Jeong Hyun Yeum

2009-01-01

216

Fragrance material review on 4-methylbenzyl acetate.  

PubMed

A toxicologic and dermatologic review of 4-methylbenzyl acetate when used as a fragrance ingredient is presented. 4-Methylbenzyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 4-methylbenzyl acetate were evaluated, then summarized, and includes: physical properties, skin irritation, skin sensitization, and elicitation data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414643

McGinty, D; Letizia, C S; Api, A M

2012-09-01

217

Polyvinyl alcohol functionalized cobalt ferrite nanoparticles for biomedical applications  

NASA Astrophysics Data System (ADS)

In the present work, cobalt ferrite nanoparticles (CoFe2O4 NPs) have been synthesized by combustion method. The surface of the CoFe2O4 NPs was modified with biocompatible polyvinyl alcohol (PVA). To investigate effect and nature of coating on the surface of CoFe2O4 NPs, the NPs were characterized X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The transmission electron microscopy (TEM) and dynamic light scattering (DLS) results demonstrate the monodispersed characteristics of CoFe2O4 NPs after surface modification with PVA. The decrease in contact angle from 162° to 50° with PVA coating on NPs indicates the transition from hydrophobic nature to hydrophilic. The Magnetic properties measurement system (MPMS) results show that the NPs have ferromagnetic behavior with high magnetization of 75.04 and 71.02 emu/g of uncoated and coated CoFe2O4 NPs respectively. These PVA coated NPs exhibit less toxicity over uncoated CoFe2O4 NPs up to 1.8 mg mL-1 when tested with mouse fibroblast L929 cell line.

Salunkhe, A. B.; Khot, V. M.; Thorat, N. D.; Phadatare, M. R.; Sathish, C. I.; Dhawale, D. S.; Pawar, S. H.

2013-01-01

218

Oil reclamation from waste plastics including polyvinyl chloride  

SciTech Connect

The purpose of this report is to present the results of plant scaleup investigations for oil reclamation from waste plastics. The reclamation process examined was thermal decomposition of polypropylene (PP) and polyvinyl chloride (PVC) under alkali addition and subsequent pressurization. Thermal analyses of the two plastics was performed, indicating that hydrogen chloride evolution occurs at around 300 C and decomposition of PP and oil formation occurs occures arount 450 C. A pilot plant was built and tested with PP and PVC pellets. In accordance with thermal analyses, the temperature of the pyrolysis chamber was raised in two steps. Pilot plant results were compared with bench-scale pilot plant and laboratory experiments. The oil reclamation ratio became smaller with an increase in the volume of the pyrolysis chamber due to temperature distributions and deposition of polymer-alkali residue. Molecular weight distributions of the recovered oil were similar for all three vessels. It was also found that the chlorine concentration in the organic chlorinated compounds in the reclaimed oil stayed below 1/30 that of the oil reclaimed from PVC decomposition without alkali in a laboratory flask-scale vessel.

Tadauchi, M. [Toshiba Corporation, Yokohama (Japan)

1995-12-31

219

Dielectric breakdown during Cs+ sputtering of polyvinyl chloride  

NASA Astrophysics Data System (ADS)

Thin films of insulating polymers are sometimes analyzed by secondary ion mass spectrometry (SIMS) or by X-ray photoelectron spectroscopy (XPS) without the use of an electron gun. In this work, both SIMS and XPS have been used to study the chemical and structural modifications due to the charge effect during Cs+ sputtering of a thin film of polyvinyl chloride (PVC). The kinetic energy distribution study shows that at a small primary fluence ˜1015 Cs+ ions/cm2, the dielectric breakdown voltage of the PVC film is reached, i.e. the minimum voltage that causes a portion of an insulator to become electrically conductive. XPS study indicates that the conducting phase created in the PVC film after energetic Cs+ bombardment consists of graphitized carbon and metallic cesium clusters. After the dielectric breakdown of the film, the positive charge, previously accumulated on the surface, is neutralized through the conductive regions, which are created in the insulating film. During Cs+ sputtering of a PVC film, the chemical structure of the analyzed surface is completely modified and some ionic bonds such as CsC and CsCl are also created.

Wahoud, F.; Guillot, J.; Audinot, J. N.; Bertrand, P.; Delcorte, A.; Migeon, H. N.

2014-02-01

220

Respiratory illness caused by overheating of polyvinyl chloride.  

PubMed Central

On 9 August 1979, 62 (30.8%) of 201 workers and one of 60 management personnel in a polyvinyl chloride (PVC) fabricating plant developed acute upper and lower respiratory irritation, headache, nausea, and fainting. All were taken to hospital; none died. Sixty of the patients were women. Interviews two weeks later with 57 affected and 14 unaffected workers disclosed that illness had followed exposure to fumes from an overheated (362 degrees C) PVC extruding machine. Fumes were emitted from 1100 until 1150; cases occurred from 1100 until late afternoon. All workers who became ill worked west of the overheated extruder, and the affected manager had visited that area. The earliest cases occurred closest to the machine, and incidence decreased (from 53.3% to 15.4%) with distance westward. This pattern was consistent with plant ventilation. Incidence rates in men and women did not differ (p greater than 0.1). At two and 14 weeks, pulmonary function testing of workers with persistent pulmonary symptoms showed abnormalities in 13 of 16 and in 9 of 11 respectively; the group with persistent symptoms contained an excess of non-smokers and of those with previous respiratory illnesses. One kilogram of PVC heated to 300 degrees C releases an estimated 12.9 g of hydrochloric acid (HCl) and 4.9 g of carbon monoxide (CO). We attributed the outbreak to exposure to toxic HCl and CO and rejected the hypothesis of mass psychogenic illness. PMID:7093150

Froneberg, B; Johnson, P L; Landrigan, P J

1982-01-01

221

Preparation and flammability of poly(vinyl alcohol) composite aerogels.  

PubMed

Poly(vinyl alcohol) (PVOH)-based aerogel composites with nanoscale silica, halloysite, montmorillonite (MMT), and laponite were prepared via a freeze-drying method. The PVOH/MMT and PVOH/laponite composites exhibit higher compressive moduli than the PVOH/SiO2 or PVOH/halloysite samples. Layered microstructures were observed for the samples except with PVOH/laponite, which showed irregular network morphologies. Thermogravimetric analysis of the aerogel samples showed increased thermal stability with the addition of nanofillers. The heat release measured by cone calorimetry, smoke release, and carbon monoxide production of the aerogel composites are all significantly decreased with the addition of nanofillers; these values are much lower than those for commercial expanded polystyrene foam. The fillers did not lead to obvious increases in the limiting oxygen index values, and the corresponding time to ignition values decrease. The ability to adjust the nanofiller levels in these foamlike aerogel composites allows for specific tuning of these products for fire safety. PMID:24731187

Chen, Hong-Bing; Wang, Yu-Zhong; Schiraldi, David A

2014-05-14

222

Electrospun chitosan/polyvinyl alcohol nanofibre mats for wound healing.  

PubMed

Chitosan (CS) aqueous salt blended with polyvinyl alcohol (PVA) nanofibre mats was prepared by electrospinning. CS was dissolved with hydroxybenzotriazole (HOBt), thiamine pyrophosphate (TPP) and ethylenediaminetetraacetic acid (EDTA) in distilled water without the use of toxic or hazardous solvents. The CS aqueous salts were blended with PVA at different weight ratios, and the effect of the solution ratios was investigated. The morphologies and mechanical and swelling properties of the generated fibres were analysed. Indirect cytotoxicity studies indicated that the CS/PVA nanofibre mats were non-toxic to normal human fibroblast cells. The CS-HOBt/PVA and CS-EDTA/PVA nanofibre mats demonstrated satisfactory antibacterial activity against both gram-positive and gram-negative bacteria, and an in vivo wound healing test showed that the CS-EDTA/PVA nanofibre mats performed better than gauze in decreasing acute wound size during the first week after tissue damage. In conclusion, the biodegradable, biocompatible and antibacterial CS-EDTA/PVA nanofibre mats have potential for use as wound dressing materials. PMID:22925275

Charernsriwilaiwat, Natthan; Rojanarata, Theerasak; Ngawhirunpat, Tanasait; Opanasopit, Praneet

2014-04-01

223

Acetic acid production from food wastes using yeast and acetic acid bacteria micro-aerobic fermentation.  

PubMed

In this study, yeast and acetic acid bacteria strains were adopted to enhance the ethanol-type fermentation resulting to a volatile fatty acids yield of 30.22 g/L, and improve acetic acid production to 25.88 g/L, with food wastes as substrate. In contrast, only 12.81 g/L acetic acid can be obtained in the absence of strains. The parameters such as pH, oxidation reduction potential and volatile fatty acids were tested and the microbial diversity of different strains and activity of hydrolytic ferment were investigated to reveal the mechanism. The optimum pH and oxidation reduction potential for the acetic acid production were determined to be at 3.0-3.5 and -500 mV, respectively. Yeast can convert organic matters into ethanol, which is used by acetic acid bacteria to convert the organic wastes into acetic acid. The acetic acid thus obtained from food wastes micro-aerobic fermentation liquid could be extracted by distillation to get high-pure acetic acid. PMID:25416587

Li, Yang; He, Dongwei; Niu, Dongjie; Zhao, Youcai

2015-05-01

224

Tested Demonstrations: Buffer Capacity of Various Acetic Acid-Sodium Acetate Systems: A Lecture Experiment.  

ERIC Educational Resources Information Center

Background information and procedures are provided for a lecture experiment which uses indicators to illustrate the concept of differing buffer capacities by titrating acetic acid/sodium acetate buffers with 1.0 molar hydrochloric acid and 1.0 molar sodium hydroxide. A table with data used to plot the titration curve is included. (JN)

Donahue, Craig J.; Panek, Mary G.

1985-01-01

225

Acetylation of Starch with Vinyl Acetate in Imidazolium Ionic Liquids and Characterization of Acetate Distribution  

Technology Transfer Automated Retrieval System (TEKTRAN)

Starch was acetylated with vinyl acetate in different 1-butyl-3-methylimidazolium (BMIM) salts as solvent in effort to produce starches with different acetylation patterns. Overall degree of substitution was much higher for basic anions such as acetate and dicyanimide (dca) than for neutral anions ...

226

A mammalian acetate switch regulates stress erythropoiesis  

PubMed Central

Endocrine erythropoietin (Epo), which is synthesized in the kidney or liver of adult mammals, controls erythrocyte production and is regulated by the stress-responsive transcription factor Hypoxia Inducible Factor 2 (HIF-2). We previously reported that the lysine acetyltransferase Cbp is required for HIF-2? acetylation and efficient HIF-2 dependent Epo induction during hypoxia. We now show these processes require acetate-dependent acetyl CoA synthetase 2 (Acss2). In Hep3B hepatoma cells and in Epo-generating organs of hypoxic or acutely anemic mice, acetate levels increase and Acss2 is required for HIF-2? acetylation, Cbp/HIF-2? complex formation and recruitment to the Epo enhancer, and efficient Epo induction. In acutely anemic mice, acetate supplementation augments stress erythropoiesis in an Acss2-dependent manner. In acquired and genetic chronic anemia mouse models, acetate supplementation also increases Epo expression and resting hematocrits. Thus, a mammalian stress-responsive acetate switch controls HIF-2 signaling and Epo induction during pathophysiological states marked by tissue hypoxia. PMID:25108527

Xu, Min; Nagati, Jason S.; Xie, Jian; Li, Jiwen; Walters, Holly; Moon, Young-Ah; Gerard, Robert D.; Huang, Chou-Long; Comerford, Sarah A.; Hammer, Robert E.; Horton, Jay D.; Chen, Rui; Garcia, Joseph A.

2014-01-01

227

A systematic study of the effect of molecular weights of polyvinyl alcohol on polyvinyl alcohol-graphene oxide composite hydrogels.  

PubMed

Polyvinyl alcohol (PVA) hydrogels have been proposed for use as promising biomaterials in biomedical and tissue engineering, and graphene oxide (GO) has been recognized as a unique two-dimensional building block for various graphene-based supramolecular architectures. In this article, we systematically studied the influence of three kinds of PVA with different molecular weights on the interaction between PVA and GO. Moreover, the effects of PVA on the gelation of GO were also investigated. The native PVA hydrogel, as well as PVA-GO hybrid hydrogels, have been thoroughly characterized by the phase behavior study and various techniques including field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and rheological measurements. It can be seen that with the increase of the molecular weight of PVA, the addition of GO can effectively promote the gelation of PVA which can be reflected by a decrease of the critical gel concentration (CGC) for PVA-GO hydrogels. Dye adsorption experiments indicate that the toxic dye, i.e., methylene blue (MB), was efficiently entrapped in the PVA-GO xerogels. It is also demonstrated that the gelation of PVA and GO composites can be promoted by different supramolecular interactions, including hydrogen bonding and electrostatic interaction. This work indicates that the PVA-GO composite is a good candidate for preparing "super" and "smart" hydrogels and will enable further studies on the supramolecular chemistry of PVA, graphene and its derivatives. PMID:25613714

Xue, Rongrong; Xin, Xia; Wang, Lin; Shen, Jinglin; Ji, Fangrui; Li, Wenzhe; Jia, Chunyu; Xu, Guiying

2015-02-21

228

Identification method of synthetic polymers by high-performance liquid chromatography  

SciTech Connect

Polyvinyl chloride (PVC), polyvinyl acetate (PVAc), and their copolymers and blends, polystyrene, poly(methyl, ethyl, and butyl) acrylates and methacrylates were dissolved in tetrahydrofuran (THF), respectively, and the solutions were injected into a column of silica gel having a pore diameter of 30 A and eluted with the mobile phases of THF, chloroform, ethyl acetate, methanol, methylethylketone, acetonitrile and 1,2-dichloroethane (DCE). Some polymers eluted from the column and the rest were retained in the column. The identification of the polymers was not based on the difference in the retention volumes of the polymers, but the elution of the polymers from or the retention in the column were a measure of the identification. This technique was termed as On-Off Elution Method'. Two retention mechanisms were proposed: hydrogen bonding between silica gel and the sample polymers, and the precipitation of polymers in the column. In case of the former, some polymers were retained in the column even though a good solvent to the polymers was used as the mobile phase. When poor solvents to the polymers were used as the mobile phases, the polymers were precipitated in the column, except PVC with DCE. The physical blend of PVC and PVAc could be discriminated from the copolymer having the same composition by this procedure.

Mori, Sadao (Mie Univ., Tsu (Japan))

1993-01-01

229

FTIR studies of plasticized poly(vinyl alcohol)-chitosan blend doped with NH 4NO 3 polymer electrolyte membrane  

NASA Astrophysics Data System (ADS)

Fourier transform infrared (FTIR) spectroscopy studies of poly(vinyl alcohol) (PVA), and chitosan polymer blend doped with ammonium nitrate (NH 4NO 3) salt and plasticized with ethylene carbonate (EC) have been performed with emphasis on the shift of the carboxamide, amine and hydroxyl bands. 1% acetic acid solution was used as the solvent. It is observed from the chitosan film spectrum that evidence of polymer-solvent interaction can be observed from the shifting of the carboxamide band at 1660 cm -1 and the amine band at 1591 cm -1 to 1650 and 1557 cm -1 respectively and the shift of the hydroxyl band from 3377 to 3354 cm -1. The hydroxyl band in the spectrum of PVA powder is observed at 3354 cm -1 and is observed at 3343 cm -1 in the spectrum of the PVA film. On addition of NH 4NO 3 up to 30 wt.%, the carboxamide, amine and hydroxyl bands shifted from 1650, 1557 and 3354 cm -1 to 1642, 1541 and 3348 cm -1 indicating that the chitosan has complexed with the salt. In the PVA-NH 4NO 3 spectrum, the hydroxyl band has shifted from 3343 to 3272 cm -1 on addition of salt from 10 to 30 wt.%. EC acts as a plasticizing agent since there is no shift in the bands as observed in the spectrum of PVA-chitosan-EC films. The mechanism of ion migration is proposed for the plasticized and unplasticized PVA-chitosan-NH 4NO 3 systems. In the spectrum of PVA-chitosan-NH 4NO 3-EC complex, the doublet C dbnd O stretching in EC is observed in the vicinity 1800 and 1700. This indicates that there is some interaction between the salt and EC.

Kadir, M. F. Z.; Aspanut, Z.; Majid, S. R.; Arof, A. K.

2011-03-01

230

Carboxyl-modified poly(vinyl alcohol)-crosslinked chitosan hydrogel films for potential wound dressing.  

PubMed

The objective of this study was to develop a novel carboxyl-modified poly(vinyl alcohol)-crosslinked chitosan hydrogel films for potential wound dressing. To prepare the crosslinked hydrogels, poly(vinyl alcohol) (PVA) was grafted with succinate acid to yield carboxyl-modified poly(vinyl alcohol) (PVA-COOH). Hydrogel films based on PVA-COOH and chitosan (CS) at different concentrations were crosslinked through the formation of amide linkages. The mechanical properties of these crosslinked hydrogel films in dry and swollen state were greatly improved with high swelling ratio. Water vapor and oxygen permeability evaluations indicated that crosslinked hydrogel films could maintain a moist environment over wound bed. Biocompatibility test showed the crosslinked hydrogels had no cytotoxicity and hemolytic potential. Gentamicin sulfate-loaded crosslinked hydrogel films showed sustained drug release profile, and could effectively suppress bacterial proliferation and protect wound from infection. PMID:25857974

Zhang, Di; Zhou, Wei; Wei, Bing; Wang, Xin; Tang, Rupei; Nie, Jiemin; Wang, Jun

2015-07-10

231

Semicrystalline poly(vinyl alcohol) films and their blends with poly(acrylic acid) and poly(ethylene glycol)  

E-print Network

291 Semicrystalline poly(vinyl alcohol) films and their blends with poly(acrylic acid) and poly@che.utexas.edu Semicrystalline films of poly(vinyl alcohol) (PVA) were prepared by annealing amorphous PVA films at temperatures, which stabilized the films and made them behave as if they were chemically cross-linked. Films were

Peppas, Nicholas A.

232

Process for the preparation of vinyl acetate  

DOEpatents

This invention pertains to the preparation of vinyl acetate by contacting within a contact zone a mixture of ketene and acetaldehyde with an acid catalyst at about one bar pressure and between about 85.degree. and 200.degree. C. and removing the reaction products from the contact zone.

Tustin, Gerald Charles (Kingsport, TN); Zoeller, Joseph Robert (Kingsport, TN); Depew, Leslie Sharon (Kingsport, TN)

1998-01-01

233

Process for the preparation of vinyl acetate  

DOEpatents

This invention pertains to the preparation of vinyl acetate by contacting within a contact zone a mixture of ketene and acetaldehyde with an acid catalyst at about one bar pressure and between about 85 and 200 C and removing the reaction products from the contact zone.

Tustin, G.C.; Zoeller, J.R.; Depew, L.S.

1998-02-17

234

Fragrance material review on ?-methylbenzyl acetate.  

PubMed

A toxicologic and dermatologic review of ?-methylbenzyl acetate when used as a fragrance ingredient is presented. ?-Methylbenzyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for ?-methylbenzyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, and repeated dose data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22406576

McGinty, D; Letizia, C S; Api, A M

2012-09-01

235

Treatment of Pedophilia with Leuprolide Acetate  

Microsoft Academic Search

To date, the literature on the treatment of individuals who have committed sexual offenses has focused primarily on psychotherapeutic interventions and the use of antiandrogens. Recently case reports and small series supporting the efficacy of other psychiatric medication, such as serotonin reuptake inhibitors, have been published. Only a few publications have looked at the efficacy of leuprolide acetate, an LH-RH

Nancy Raymond; Bean Robinson; Chris Kraft; Barry Rittberg; Eli Coleman

2002-01-01

236

Corrosion of stainless steel during acetate production  

SciTech Connect

Corrosion of types 304, 304L, 316, and 316L stainless steel (SS) during the esterification of acetic acid and alcohol or glycol ether was investigated. The catalyst for this reaction, sulfuric acid or para-toluene sulfonic acid (PTSA), was shown to cause more corrosion on reactor equipment than CH{sub 3}COOH under the process conditions commonly practiced in industry. The corrosive action of the catalyst occurred only in the presence of water. Thus, for the batch processes, corrosion occurred mostly during the initial stage of esterification, where water produced by the reaction created an aqueous environment. After water was distilled off, the corrosion rate declined to a negligible value. The corrosion inhibitor copper sulfate, often used in industrial acetate processes, was found to work well for a low-temperature process (< 95 C) such as in production of butyl acetate, but it accelerated corrosion in the glycol ether acetate processes where temperatures were > 108 C. Process conditions that imparted low corrosion rates were determined.

Qi, J.S.; Lester, G.C. [Occidental Chemical Corp. Technology Center, Grand Island, NY (United States)

1996-07-01

237

Fragrance material review on piperonyl acetate.  

PubMed

A toxicologic and dermatologic review of piperonyl acetate when used as a fragrance ingredient is presented. Piperonyl acetate is a member of the fragrance structural group aryl alkyl alcohol simple acid esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for piperonyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, toxicokinetics, and genotoxicity data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22445840

McGinty, D; Letizia, C S; Api, A M

2012-09-01

238

Fragrance material review on benzyl acetate.  

PubMed

A toxicologic and dermatologic review of benzyl acetate when used as a fragrance ingredient is presented. Benzyl acetate is a member of the fragrance structural group aryl alkyl alcohol simple acid esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for benzyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, phototoxicity, toxicokinetics, repeated dose, reproductive toxicity, genotoxicity, or carcinogenicity data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Refer Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22387848

McGinty, D; Vitale, D; Letizia, C S; Api, A M

2012-09-01

239

Fragrance material review on 2-phenylpropyl acetate.  

PubMed

A toxicologic and dermatologic review of 2-phenylpropyl acetate when used as a fragrance ingredient is presented. 2-Phenylpropyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 2-phenylpropyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, and skin sensitization data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22421639

McGinty, D; Letizia, C S; Api, A M

2012-09-01

240

Heat Bonding of Irradiated Ethylene Vinyl Acetate  

NASA Technical Reports Server (NTRS)

Reliable method now available for joining parts of this difficult-tobond material. Heating fixture encircles ethylene vinyl acetate multiplesocket part, providing heat to it and to tubes inserted in it. Fixtures specially designed to match parts to be bonded. Tube-and-socket bonds made with this technique subjected to tensile tests. Bond strengths of 50 percent that of base material obtained consistently.

Slack, D. H.

1986-01-01

241

Spray-on polyvinyl alcohol separators and impact on power production in air-cathode microbial fuel cells with different solution conductivities  

E-print Network

Spray-on polyvinyl alcohol separators and impact on power production in air-cathode microbial fuel, PA 16802, USA h i g h l i g h t s Polyvinyl alcohol (PVA) separators were prepared with spray Polyvinyl alcohol a b s t r a c t Separators are used to protect cathodes from biofouling and to avoid

242

Structural and electronic properties of poly(vinyl alcohol) using density functional theory  

SciTech Connect

The first principles calculations have been carried out to investigate the structural, electronic band structure density of states along with the projected density of states for poly(vinyl alcohol). Our structural calculation suggests that the poly(vinyl alcohol) exhibits monoclinic structure. The calculated structural lattice parameters are in excellent agreement with available experimental values. The band structure calculations reveal that the direct and indirect band gaps are 5.55 eV and 5.363 eV respectively in accordance with experimental values.

Dabhi, Shweta, E-mail: shwetadabhi1190@gmail.com; Jha, Prafulla K., E-mail: shwetadabhi1190@gmail.com [Department of Physics, Maharaja Krishnakumasinhji Bhavnagar University, Bhavnagar-364001 (India)

2014-04-24

243

CORROSION OF LEAD SHIELDING IN MODEL 9975 PACKAGE  

SciTech Connect

Experiments were performed to determine the corrosion rate of lead when exposed to off-gas or degradation products of organic materials used in the model 9975 package.[1] The experiments were completed within the framework of a parametric test matrix with variables of organic configuration, temperature, humidity and the effect of durations of exposure on the corrosion of lead in the 9975 package. The room temperature vulcanizing (RTV) sealant was the most corrosive organic species in the testing, followed by the polyvinyl acetate (PVAc) glue. The Celotex{copyright} material uniquely induced measurable corrosion only in situations with condensed water, and to a much lesser extent than the PVAc glue and RTV. The coupons exhibited faster corrosion at higher temperatures than at room temperatures. There was a particularly pronounced effect of condensed water as the coupons exposed in the cells with condensed water exhibited much higher corrosion rates. In the 9975 package, the PVAc glue was determined to be the most aggressive due to it's proximity in the design. The condition considered most representative of the package conditions is that of the coupon exposed to the Celotex{copyright}/glue organic exposed in the ambient humidity conditions. The corrosion rate of 2 mpy measured in the laboratory experiments for this condition is considered to be a bounding condition to the 9975 package conditions when the laboratory results are extrapolated to actual package conditions, and is recommended as a conservative estimate for package performance calculations.

Subramanian, K

2006-03-15

244

Electrospinning processed nanofibrous TiO2 membranes for photovoltaic applications  

NASA Astrophysics Data System (ADS)

We have recently fabricated dye-sensitized solar cells (DSSCs) comprising nanofibrous TiO2 membranes as electrode materials. A thin TiO2 film was pre-deposited on fluorine doped tin oxide (FTO) coated conducting glass substrate by immersion in TiF4 aqueous solution to reduce the electron back-transfer from FTO to the electrolyte. The composite polyvinyl acetate (PVac)/titania nanofibrous membranes can be deposited on the pre-deposited thin TiO2 film coated FTO by electrospinning of a mixture of PVac and titanium isopropoxide in N,N-dimethylformamide (DMF). The nanofibrous TiO2 membranes were obtained by calcining the electrospun composite nanofibres of PVac/titania as the precursor. Spectral sensitization of the nanofibrous TiO2 membranes was carried out with a ruthenium (II) complex, cis-dithiocyanate-N,N'-bis(2,2'-bipyridyl-4,4'-dicarboxylic acid) ruthenium (II) dihydrate. The results indicated that the photocurrent and conversion efficiency of electrodes can be increased with the addition of the pre-deposited TiO2 film and the adhesion treatment using DMF. Additionally, the dye loading, photocurrent, and efficiency of the electrodes were gradually increased by increasing the average thickness of the nanofibrous TiO2 membranes. The efficiency of the fibrous TiO2 photoelectrode with the average membrane thickness of 3.9 µm has a maximum value of 4.14%.

Onozuka, Katsuhiro; Ding, Bin; Tsuge, Yosuke; Naka, Takayuki; Yamazaki, Michiyo; Sugi, Shinichiro; Ohno, Shingo; Yoshikawa, Masato; Shiratori, Seimei

2006-02-01

245

Flexible latex—polyaniline segregated network composite coating capable of measuring large strain on epoxy  

NASA Astrophysics Data System (ADS)

A new conductive polymer nanocomposite (CPC) strain sensor, with a segregated network of polyaniline nanoparticles in a poly(vinyl acetate) latex matrix (PVAc-PANI), was created to improve upon existing systems. The strain sensing capabilities of these CPC transducers, attached to epoxy beams, were determined by subjecting them to loading/unloading cycles up to 1% strain (and straining them until the epoxy beam failed (around 5% strain)), in uniaxial tension. Microstructural images and visco-elastic properties show that these CPC are homogeneous and behave much like neat PVAc. PVAc with 4 wt.% PANI provided the best compromise among high sensitivity, small hysteresis and low noise. These environmentally friendly, flexible and low cost strain sensors are capable of monitoring strain above 5%, with a gauge factor between 6 and 8 (3 times those of classical metallic gauges). Moreover, this technology can be easily scaled up to monitor deformations of large composite structures, opening up many promising areas (e.g., damage detection for aircraft).

Levin, Z. S.; Robert, C.; Feller, J. F.; Castro, M.; Grunlan, J. C.

2013-01-01

246

Organic/inorganic nanocomposites, methods of making, and uses as a permeable reactive barrier  

DOEpatents

Nanocomposite materials having a composition including an inorganic constituent, a preformed organic polymer constituent, and a metal ion sequestration constituent are disclosed. The nanocomposites are characterized by being single phase, substantially homogeneous materials wherein the preformed polymer constituent and the inorganic constituent form an interpenetrating network with each other. The inorganic constituent may be an inorganic oxide, such as silicon dioxide, formed by the in situ catalyzed condensation of an inorganic precursor in the presence of the solvated polymer and metal ion sequestration constituent. The polymer constituent may be any hydrophilic polymer capable of forming a type I nanocomposite such as, polyacrylonitrile (PAN), polyethyleneoxide (PEO), polyethylene glycol (PEG), polyvinyl acetate (PVAc), polyvinyl alcohol (PVA), and combinations thereof. Nanocomposite materials of the present invention may be used as permeable reactive barriers (PRBs) to remediate contaminated groundwater. Methods for making nanocomposite materials, PRB systems, and methods of treating groundwater are also disclosed.

Harrup, Mason K. (Idaho Falls, ID); Stewart, Frederick F. (Idaho Falls, ID)

2007-05-15

247

Novel nanosized water soluble fluorescent micelles with embedded perylene diimide fluorophores for potential biomedical applications: Cell permeability, localization and cytotoxicity.  

PubMed

Novel biocompatible water-soluble fluorescent micelles with embedded perylene diimides (PDI) for intracellular applications have been prepared by self assembling of amphiphilic poly(vinyl alcohol)-b-poly(acrylonitrile) (PVA-b-PAN) copolymers in the presence of synthesized fluorophores. Amphiphilic PVA-b-PAN copolymers were obtained by selective hydrolysis of well-defined poly(vinyl acetate)-b-poly(acrylonitrile) (PVAc-b-PAN) copolymer. The preparation of the novel fluorescence micelles consisting of PVA hydrophilic shell and PAN hydrophobic core with incorporated PDI fluorophores has been confirmed by DLS and TEM analysis. The cytotoxicity of the water-soluble fluorophores and their internalization into living cells depending on the micellar concentration have been tested. It was shown that they could successfully enter in living cells without destroying their morphology. The results obtained indicate that the novel water-soluble fluorescent micelles with embedded PDI fluorophores would be suitable for potential intracellular biomedical applications. PMID:25842102

Bryaskova, Rayna; Georgiev, Nikolai I; Dimov, Stefan M; Tzoneva, Rumiana; Detrembleur, Christophe; Asiri, Abdullah M; Alamry, Khalid A; Bojinov, Vladimir B

2015-06-01

248

The microwave spectrum of n-hexyl acetate and structural aspects of n-alkyl acetates  

NASA Astrophysics Data System (ADS)

The microwave spectrum of n-hexyl acetate was recorded in the range of 10-13.5 GHz using the Aachen MB-FTMW spectrometer. The rotational constants of the most abundant conformer were determined to be A = 3.3591100(32) GHz, B = 0.39596553(53) GHz, and C = 0.36999804(31) GHz. Quantum chemical calculations for specific conformers were carried out at the MP2/6-311++G(d,p) level. The programs XIAM and BELGI were used to analyze the internal rotation of the acetyl methyl group. The observed conformer of n-hexyl acetate was compared to the lowest energy conformers of n-butyl acetate and n-pentyl acetate.

Attig, T.; Kannengießer, R.; Kleiner, I.; Stahl, W.

2014-04-01

249

Phenyl Acetate Preparation from Phenol and Acetic Acid: Reassessment of a Common Textbook Misconception.  

ERIC Educational Resources Information Center

Reassesses a common textbook misconception that "...phenols cannot be esterified directly." Results of experiments are discussed and data tables provided of an effective method for the direct preparation of phenyl acetate. (CS)

Hocking, M. B.

1980-01-01

250

Release characteristics of diclofenac sodium from poly(vinyl alcohol)\\/sodium alginate and poly(vinyl alcohol)-grafted-poly(acrylamide)\\/sodium alginate blend beads  

Microsoft Academic Search

In this study, acrylamide (AAm) was grafted onto poly(vinyl alcohol) (PVA) with UV radiation at ambient temperature. The graft copolymer (PVA-g-PAAm) was characterized by using Fourier transform infrared spectroscopy (FTIR), elemental analysis and differential scanning calorimetry (DSC). Polymeric blend beads of PVA-g-PAAm and PVA with sodium alginate (NaAlg) were prepared by cross-linking with glutaraldehyde (GA) and used to deliver a

Oya ?anl?; Nuran Ay; Nuran I??klan

2007-01-01

251

Expression of acetate permease-like (apl) genes in subsurface communities of Geobacter species under fluctuating acetate concentrations  

SciTech Connect

The addition of acetate to uranium-contaminated aquifers in order to stimulate the growth and activity of Geobacter species that reduce uranium is a promising in situ bioremediation option. Optimizing this bioremediation strategy requires that sufficient acetate be added to promote Geobacter species growth. We hypothesized that under acetate-limiting conditions, subsurface Geobacter species would increase the expression of either putative acetate symporters genes (aplI and aplII). Acetate was added to a uranium-contaminated aquifer (Rifle, CO) in two continuous amendments separated by 5 days of groundwater flush to create changing acetate concentrations. While the expression of aplI in monitoring well D04 (high acetate) weakly correlated with the acetate concentration over time, the transcript levels for this gene were relatively constant in well D08 (low acetate). At the lowest acetate concentrations during the groundwater flush, the transcript levels of aplII were the highest. The expression of aplII decreased 2-10-fold upon acetate reintroduction. However, the overall instability of acetate concentrations throughout the experiment could not support a robust conclusion regarding the role of apl genes in response to acetate limitation under field conditions, in contrast to previous chemostat studies, suggesting that the function of a microbial community cannot be inferred based on lab experiments alone.

Elifantz, H.; N'Guessan, L.A.; Mouser, P.J.; Williams, K H.; Wilkins, M J.; Risso, C.; Holmes, D.E.; Long, P.E.; Lovley, D.R.

2010-03-01

252

Acetate concentrations and oxidation in salt marsh sediments  

NASA Technical Reports Server (NTRS)

Acetate concentrations and rates of acetate oxidation and sulfate reduction were measured in S. alterniflora sediments in New Hampshire and Massachusetts. Pore water extracted from cores by squeezing or centrifugation contained in greater than 0.1 mM acetate and, in some instances, greater than 1.0 mM. Pore water sampled nondestructively contained much less acetate, often less than 0.01 mM. Acetate was associated with roots, and concentrations varied with changes in plant physiology. Acetate turnover was very low whether whole core or slurry incubations were used. Radiotracers injected directly into soils yielded rates of sulfate reduction and acetate oxidation not significantly different from core incubation techniques. Regardless of incubation method, acetate oxidation did not account for a substantial percentage of sulfate reduction. These results differ markedly from data for unvegetated coastal sediments where acetate levels are low, oxidation rate constants are high, and acetate oxication rates greatly exceed rates of sulfate reduction. The discrepancy between rates of acetate oxidation and sulfate reduction in these marsh soils may be due either to the utilization of substrates other than acetate by sulfate reducers or artifacts associated with measurements of organic utilization by rhizosphere bacteria. Care must be taken when interpreting data from salt marsh sediments since the release of material from roots during coring may affect the concentrations of certain compounds as well as influencing results obtained when sediment incubations are employed.

1992-01-01

253

Kinetics of Ethyl Acetate Synthesis Catalyzed by Acidic Resins  

ERIC Educational Resources Information Center

A low-cost experiment to carry out the second-order reversible reaction of acetic acid esterification with ethanol to produce ethyl acetate is presented to illustrate concepts of kinetics and reactor modeling. The reaction is performed in a batch reactor, and the acetic acid concentration is measured by acid-base titration versus time. The…

Antunes, Bruno M.; Cardoso, Simao P.; Silva, Carlos M.; Portugal, Ines

2011-01-01

254

Lithium acetate transformation of yeast Maitreya Dunham August 2004  

E-print Network

Lithium acetate transformation of yeast Maitreya Dunham August 2004 Original protocol from Katja until the OD600 is around 0.7-0.8 (~7 hours). Spin down the cells. Resuspend in 5 ml lithium acetate mix. Spin. Resuspend in 0.5 ml lithium acetate mix. Transfer to an eppendorf tube. Incubate 60 minutes

Dunham, Maitreya

255

Influence of lead acetate on hypersensitivity. Experimental study.  

PubMed

Recent studies showed that lead acetate has an important immunotoxicity for the phagocytic activity as well as humoral and cell-mediated immunity. We studied the influence of lead acetate on immediate and delayed hypersensitivity. The lead acetate exerts an important action on hypersensitivity reactions whether on rat mast cells degranulation (immediate hypersensitivity) or on contact hypersensitivity. PMID:6470497

Laschi-Loquerie, A; Descotes, J; Tachon, P; Evreux, J C

1984-01-01

256

Comparison of storage stability of odorous VOCs in polyester aluminum and polyvinyl fluoride tedlar bags  

Technology Transfer Automated Retrieval System (TEKTRAN)

Whole air sampling using containers such as flexible bags or rigid canisters is commonly used to collect samples of volatile organic compounds (VOC) in air. The objective of this study was to compare the stability of polyester aluminum (PEA) and polyvinyl fluoride (PVF, brand name Tedlar®) bags for ...

257

Recovery of agricultural odors and odorous compounds from polyvinyl fluoride film bags  

Technology Transfer Automated Retrieval System (TEKTRAN)

Accurate sampling methods are necessary when quantifying odor and volatile organic compound emissions at agricultural facilities. The commonly accepted methodology in the U.S. has been to collect odor samples in polyvinyl fluoride bags (PVF, brand name Tedlar®) and, subsequently, analyze with human ...

258

Influence of smoke from the combustion of polyvinyl chloride insulation on northern hardwood forest species  

Microsoft Academic Search

Open burning is often used as a method of removing insulation from wire in salvage operations. Forest communities in the vicinity of an open burning site in northern Pennsylvania where polyvinyl chloride (PVC) insulation was being burned from copper wire were examined. Chlorotic flecks of the upper leaf surface, red-brown to black necrotic spots on the leaves, defoliation, and death

Wood

1968-01-01

259

Tensile and thermal properties of nanocellulose-reinforced poly(vinyl alcohol) nanocomposites  

Microsoft Academic Search

This work reports on the mechanical and thermal properties of poly(vinyl alcohol) (PVA) nanocomposites reinforced with nanocelluloses isolated by the sulfuric acid hydrolysis using commercial microcrystalline cellulose (MCC). Nanocellulose-reinforced PVA nanocomposite films were prepared by the casting method with different nanocellulose loadings, which were exposed to tensile test, thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The nanocellulose obtained by

Mi-Jung Cho; Byung-Dae Park

2011-01-01

260

Long-term dimensional stability and reproduction of surface detail of four polyvinyl siloxane duplicating materials  

Microsoft Academic Search

ObjectivesDuplicating materials must routinely accurately reproduce the details of dental casts and thus contribute significantly to the close adaptation and success of a removable prosthesis or fixed indirect restoration. It is important to establish the long-term dimensional stability of polyvinyl siloxane materials (PVS) as they are widely used in dental technology and over the duration of a course of treatment,

Ravi Pant; Andrzej S. Juszczyk; Robert K. F. Clark; David R. Radford

2008-01-01

261

Polyvinyl pyridine metal complex as permanent antimicrobial finishing for viscose fabric  

Microsoft Academic Search

Viscose fabrics were treated with polyvinyl pyridine (PVP) using padding technique, followed by oxidation with hydrogen peroxide or peracetic acid, which was prepared by the reaction of tetra acetyl ethylene diamine (TAED) with hydrogen peroxide.Peracetic acid gives higher oxidation of PVP than hydrogen peroxide. FTIR study proved the formation of N-oxide as a result of oxidation. Incorporation of copper and

A. Kantouch; A. Atef El-Sayed

2008-01-01

262

Linear Dichroism of Cyanine Dyes in Stretched Polyvinyl Alcohol Films: A Physical Chemistry Laboratory Experiment.  

ERIC Educational Resources Information Center

Provides background information, procedures, and results of an undergraduate physical chemistry experiment on the polarization of absorption spectra of cyanine dyes in stretched polyvinyl alcohol films. The experiment gives a simple demonstration of the concept of linear dichromism and the validity of the TEM method used in the analyses. (JN)

Natarajan, L. V.; And Others

1983-01-01

263

Note and Record A note on polyvinyl chloride (PVC) pipe traps for  

E-print Network

Note and Record A note on polyvinyl chloride (PVC) pipe traps for sampling vegetation of traditional traps, and many are furtive (Myers et al., 2007; Pittman et al., 2008). PVC pipe traps, which and Hyperolius (see Channing, 2001; du Preez & Carruthers, 2009), may be attracted to artificial refugia of PVC

Pretoria, University of

264

ORIGINAL PAPER Natural Fiber Reinforced Poly(vinyl chloride) Composites: Effect  

E-print Network

Science+Business Media, LLC 2008 Abstract Poly(vinyl chloride) (PVC) and natural fiber composites were of the composites. The addition of fiber to PVC matrix increased glass transi- tion temperature (Tg), but lowered, PVC/rice husk compos- ites presented relatively smaller water absorption (WA) and thickness swelling

265

FOAMED ARTICLES BASED ON POTATO STARCH, CORN AND WHEAT FIBRE, AND POLY(VINYL ALCOHOL)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Continued research cooperation between USDA Laboratories (USA) and the University of Pisa, Italy, has yielded several composites based on blends of poly(vinyl alcohol) (PVA) and either corn or wheat fibres, co-product of the corn-wheat wet-milling process. Foam trays were prepared by baking the blen...

266

Potassium Iodide in Coloring of Polyvinyl Alcohol Film in Oxidizing Solution  

Microsoft Academic Search

Conversion of potassium iodide in polyvinyl alcohol film by its treatment in the (NH4)2S2O8- CuSO4-KI-KCl-H2SO4-H2O oxidizing solution, leading to coloring of the film with molecular iodine, was studied. The conversion mechanism was analyzed as influenced by each component of the oxidizing solution.

N. G. Ariko; V. E. Agabekov

2003-01-01

267

Polyvinyl Pyrrolidone is not Effective for Improving Recovery of Cryopreserved Shoots of Two Rubus Cultivars  

Technology Transfer Automated Retrieval System (TEKTRAN)

The use of the antioxidant polyvinyl pyrrolidone as a pretreatment or recovery treatment for Rubus shoot cultures was tested with two blackberry cultivars. Plantlet growth was initially evaluated on medium with 1 to 10% PVP (10,000 MW). Growth and multiplication of the plantlets was severely inhib...

268

Photophysical comparative study of amylose and polyvinyle pyrrolidone / single walled carbon nanotubes complex.  

E-print Network

Photophysical comparative study of amylose and polyvinyle pyrrolidone / single walled carbon : pierre.m.bonnet@univ-bpclermont.fr ABSTRACT: Progressive addition of hydroxypropylated amylose (Am structures of (a): PVP; (b): Hydroxypropylated amylose (AmH). The circle shows the hydroxypropyl side group

Paris-Sud XI, Université de

269

Preparation and Characterization of Atactic Poly(vinyl alcohol)\\/Platinum Nanocomposites by Electrospinning  

Microsoft Academic Search

Poly(vinyl alcohol) (PVA)\\/platinum composite nanofibers were successfully prepared by the electrospinning method. Water-based colloidal platinum in a PVA solution was directly mixed without any chemical or structural modifications into PVA polymer fibers to form organic-inorganic composite nanofibers. The PVA\\/platinum composite nanofibers were characterized by field emission scanning electron microscopy (SEM).

Won Seok Lyoo; Young Jae Lee; Jin Wook Cha; Min Jae Kim; Sang Woo Joo; Yeong Soon Gal; Tae Hwan Oh; Sung Soo Han

2010-01-01

270

Development of Meloxicam-Loaded Electrospun Polyvinyl Alcohol Mats as a Transdermal Therapeutic Agent  

Microsoft Academic Search

This study reports on the use of electrospun polyvinyl alcohol (PVA) nanofiber mats loaded with meloxicam (MX) as a transdermal drug delivery system. The amounts of MX loaded in the base PVA solution (10% w\\/v solution) were 2.5, 5, 10 and 20% weight, based on the dry weight of PVA (% wt). The average diameters of these fibers ranged from

Tanasait Ngawhirunpat; Praneet Opanasopit; Theerasak Rojanarata; Prasert Akkaramongkolporn; Uracha Ruktanonchai; Pitt Supaphol

2009-01-01

271

Preparation and Characterization of Atactic Poly(vinyl alcohol)/Platinum Nanocomposites by Electrospinning  

NASA Astrophysics Data System (ADS)

Poly(vinyl alcohol) (PVA)/platinum composite nanofibers were successfully prepared by the electrospinning method. Water-based colloidal platinum in a PVA solution was directly mixed without any chemical or structural modifications into PVA polymer fibers to form organic-inorganic composite nanofibers. The PVA/platinum composite nanofibers were characterized by field emission scanning electron microscopy (SEM).

Seok Lyoo, Won; Jae Lee, Young; Wook Cha, Jin; Jae Kim, Min; Woo Joo, Sang; Soon Gal, Yeong; Hwan Oh, Tae; Soo Han, Sung

2010-06-01

272

Optical dephasing of cresyl violet in a polyvinyl alcohol polymer by non-photochemical hole burning  

NASA Astrophysics Data System (ADS)

A new burn—probe sequence is utilized with non-photochemical hole burning to study the optical dephasing of impurities in polymer films. For cresyl violet in polyvinyl alcohol the temperature dependence of dephasing is close to linear in the range studied. A burn time dependence of hole width is observed and discussed.

Carter, T. P.; Fearey, B. L.; Hayes, J. M.; Small, G. J.

1983-11-01

273

Monitoring the photobleaching of cresyl violet in polyvinyl alcohol using the photoacoustic effect  

NASA Astrophysics Data System (ADS)

Bleaching of cresyl violet in polyvinyl alcohol due to irradiation by a laser beam at three chopping frequencies is investigated using the photoacoustic technique. The results indicate that the bleaching rate decreases with increase in chopping frequency. This can be used as a potential medium for holographic recording and information storage.

Philip, Annieta; Radhakrishnan, P.; Nampoori, V. P.; Vallabhan, C. P.

1994-06-01

274

CHARACTERIZATION OF BIODEGRADABLE COMPOSITE FILMS PREPARED FROM BLENDS OF POLYVINYL ALCOHOL, CORNSTARCH AND LIGNOCELLULOSICC FIBER  

Technology Transfer Automated Retrieval System (TEKTRAN)

Several composite blends of poly(vinyl alcohol) (PVA) and lignocellulosic fibers were prepared and characterized. Cohesive and flexible cast films were obtained by blending lignocellulosic fibers derived from orange waste and PVA with or without cornstarch. Films were evaluated for their thermal s...

275

Study on miscibility of poly(vinyl chloride) and polyepichlorohydrin by viscometric and thermal analysis  

Microsoft Academic Search

Viscometric analysis was carried out to study the miscibility of poly(vinyl chloride) (PVC) and polyepichlorohydrin (PECH) in various solvents, tetrahydrofuran (THF), methyl ethyl ketone (MEK) and dimethylformamide (DMF). The Krigbaum–Wall criterion is used here to evaluate the miscibility of the two components, and ?b is introduced which can be calculated from the viscosity curves. The results show that their attractive

Yiming Ren; Ruizhu Yang; Xiaoli Liu; Fengqi Liu

2011-01-01

276

Synthesis and Magnetorheological Characterization of Magnetite Nanoparticle and Poly(Vinyl Butyral) Composite  

Microsoft Academic Search

Iron oxide nanoparticle of magnetite, one of well-known soft magnetic materials, has been investigated due to their various potential applications. In order to apply it as a magnetorheological (MR) material, composite of poly(vinyl butyral) and magnetite nanoparticles was prepared via solvent evaporation method using synthesized magnetite nanoparticles because of their proper magnetic characteristics and dispersion stability in a viscous medium.

Bong Jun Park; Jae Lim You; Hyoung Jin Choi; Seong Yong Park; Byoung Yoon Lee

2009-01-01

277

Structure-sensitive film materials based on polyvinyl alcohol compositions with polyacids  

Microsoft Academic Search

The influence of polyacidic additives (silicotungstic acid -- STA, carboxymethylcellulose -- Na-CMC, polymethacrylic acid -- PMA, polyacrylic acid -- PAA) on the molecular mobility of film composition based on polyvinyl alcohol (PVA) in the temperature range 20 - 200 degree(s)C has been evaluated. It has been concluded that interpolymer complexes are formed due to hydrogen bonding of the PVA and

Tatiana G. Lazareva; Irina A. Iljushenko

1995-01-01

278

Oxidative mineralization and characterization of polyvinyl alcohol for compatibility with tank farm processing chemistry  

SciTech Connect

Polyvinyl alcohol (PVA) material has been evaluated for use as a cost-effective substitute for conventional cellulose-based disposal materials (decontamination mops and wipes), plastic bags, and disposable personal protection clothing, that are currently used at Savannah River Site. This study also provides process design criteria for ultraviolet/ultrasonic/hydrogen peroxide PVA reactor system.

Oji, L.N.

2000-01-04

279

Antimicrobial Effect of An Essential Oil Blend on Surface-attached Salmonella on Polyvinyl Chloride  

Technology Transfer Automated Retrieval System (TEKTRAN)

The majority of drinking water lines for broilers are made of polyvinyl chloride (PVC) and surface attachment of Salmonella on the inner surface of water lines can be the initial stage of biofilm development. These biofilms can be the source of Salmonella infection in water lines and are known to re...

280

Neutron attenuation characteristics of polyethylene, polyvinyl chloride, and heavy aggregate concrete and mortars.  

PubMed

Polyethylene and polyvinyl chloride pellets were introduced into concrete to improve its neutron attenuation characteristics while several types of heavy coarse aggregates were used to improve its gamma ray attenuation properties. Neutron and gamma ray attenuation were studied in concrete samples containing coarse aggregates of barite, pyrite, basalt, hematite, and marble as well as polyethylene and polyvinyl chloride pellets in narrow-beam geometry. The highest neutron attenuation was shown by polyethylene mortar, followed by polyvinyl chloride mortar; barite and pyrite concrete showed higher gamma ray attenuation than ordinary concrete. Broad-beam and continuous (infinite) medium geometries were used to study the neutron attenuation of samples containing polymers at different concentrations with and without heavy aggregates, the fitting equations were established, and from these the neutron removal coefficients were deduced. In a radiation field of neutrons and gamma rays, the appropriate concentration of polymer and heavy aggregate can be selected to give the optimum total dose attenuation depending on the relative intensities of each type of radiation. This would give much better design flexibility over ordinary concrete. The compressive strength tests performed on mortar and concrete samples showed that their value, in general, decreases as polymer concentration increases and that the polyvinyl chloride mortar showed higher values than the polyethylene mortar. For general construction purposes, the compression strength was considered acceptable in these samples. PMID:8106253

Abdul-Majid, S; Othman, F

1994-03-01

281

Neutron attenuation characteristics of polyethylene, polyvinyl chloride, and heavy aggregate concrete and mortars  

SciTech Connect

Polyethylene and polyvinyl chloride pellets were introduced into concrete to improve its neutron attenuation characteristics while several types of heavy coarse aggregates were used to improve its gamma ray attenuation properties. Neutron and gamma ray attenuation were studied in concrete samples containing coarse aggregates of barite, pyrite, basalt, hematite, and marble as well as polyethylene and polyvinyl chloride pellets in narrow-beam geometry. The highest neutron attenuation was shown by polyethylene mortar, followed by polyvinyl chloride mortar; barite and pyrite concrete showed higher gamma ray attenuation than ordinary concrete. Broad-beam and continuous (infinite) medium geometries were used to study the neutron attenuation of samples containing polymers at different concentrations with and without heavy aggregates, the fitting equations were established, and from these the neutron removal coefficients were deduced. In a radiation field of neutrons and gamma rays, the appropriate concentration of polymer and heavy aggregate can be selected to give the optimum total dose attenuation depending on the relative intensities of each type of radiation. This would give much better design flexibility over ordinary concrete. The compressive strength tests performed on mortar and concrete samples showed that their value, in general, decreases as polymer concentration increases and that the polyvinyl chloride mortar showed higher values than the polyethylene mortar. For general construction purposes, the compression strength was considered acceptable in these samples. 34 refs., 16 figs., 4 tabs.

Abdul-Majid, S.; Othman, F. [King Abdulaziz Univ., Jeddah (Saudi Arabia)

1994-03-01

282

Composite Nafion\\/polyvinyl alcohol membranes for the direct methanol fuel cell  

Microsoft Academic Search

The methanol crossover in the direct methanol fuel cell (DMFC) can be reduced by casting a thin film containing the mixture of polyvinyl alcohol (PVA) and Nafion on a commercial perfluorosulfonic membrane (Nafion, Dupont). In addition to the cell polarization testing, a design factor defined as the reciprocal of the multiplication of the methanol permeation current density and membrane area

Zhi-Gang Shao; Xin Wang; I.-Ming Hsing

2002-01-01

283

Separation of Polyvinyl Chloride from Plastic Mixture by Froth Flotation after Surface Modification with Ozone  

Microsoft Academic Search

Selective modification by ozonation for the surface of polyvinyl chloride (PVC) was evaluated to separate PVC from the other plastics, polyethylene terephthalate (PET), polycarbonate (PC) and polymethyl methacrylate (PMMA), with almost the same density as PVC by the froth flotation process. Ozonation could selectively decrease the contact angles of flexible PVC from 87.5 degrees to 68.4 degrees and rigid PVC

Tetsuji Okuda; Keisuke Kurose; Wataru Nishijima; Mitsumasa Okada

2007-01-01

284

Synthesis of chemically crosslinked poly(vinyl chloride) by vinyl chloride\\/divinyls suspension copolymerization  

Microsoft Academic Search

Vinyl chloride (VC)\\/divinyl derivative copolymerization was carried out in the suspension process for preparing chemically crosslinked poly(vinyl chloride) (PVC). Effects of the reactivity ratios and concentration of divinyl, polymerization temperature and conversion on the structure of crosslinked PVC (such as the gel fraction, polymerization degree of sol and crosslinking density of gel) were investigated. It showed that the crosslinking behavior

Yong-Zhong Bao; Zhi-Xue Weng; Zhi-Ming Huang; Zu-Ren Pan

2000-01-01

285

THE EFFECT OF IRRADIATION ON THE DIELECTRIC PROPERTIES OF POLYVINYL CHLORIDE  

Microsoft Academic Search

The most important change which appears in the polyvinyl chloride (PVC) ; molecules following irradiation is the HCl-cleavage. It is combined with the ; originating macro molecular radical and unsaturated bonds. This reaction starts ; a series of further chemical reactions for which the presence or absence of ; oxygen in the reaction zone is of decisive importance. it was

Kiessling

1961-01-01

286

Chapter 5 Development of Adiabatic Force Field for Polyvinyl Chloride PVC  

E-print Network

73 Chapter 5 Development of Adiabatic Force Field for Polyvinyl Chloride PVC and Chlorinated PVC, dielectric, and ame and smoke properties, chemical inertness, and low sensitivity to hydrocarbon costs would be to determine the non-adiabatic surface by xing all bonds and angles so that only the torsional

Goddard III, William A.

287

Adhesion of Poly(vinyl chloride) to Hydrogenated Nitrile Rubber Part 1: Peel Studies  

Microsoft Academic Search

The adhesion of poly(vinyl chloride) to hydrogenated nitrile rub ber is studied by Tpeel test. The peel-fracture energy is found to be dependent on the presence of stabilizer and plasticizer in the PVC phase, in addition to the molding and testing conditions. At high contact temperatures and long contact times, in addition to the segmental diffusion across the interface, the

N. R. Manoj; P. P. De

1994-01-01

288

Chemical modification of poly(vinyl chloride)—Still on the run  

Microsoft Academic Search

Poly(vinyl chloride) (PVC) has continued to be a research topic in polymer science since its discovery in the early 19th century. Its internal structural defects, which stem from its direct manufacture (via free radical polymerization), heighten its peculiarities, including its thermal instability. Apart from the addition of organic and inorganic thermal stabilizers, improved chemistry in the formation of PVC has

S. Moulay

2010-01-01

289

Preparation of polyvinyl alcohol-polyacrylamide composite polymer membrane by ?-irradiation for entrapment of urease  

Microsoft Academic Search

Composite polymer membrane of polyvinyl alcohol (PVA) and acrylamide was prepared on cheesecloth support by ?-irradiation induced free radical polymerization. The enzyme urease was entrapped in the membrane during polymerization and was cross-linked within the matrix using glutaraldehyde. The membranes could be reused a number of times without significant loss of urease activity.

Sandeep Kumar Jha; Stanislaus F. D'Souza

2005-01-01

290

Comparative study on polyvinyl alcohol and alginate for cell immobilization in biosorption  

Microsoft Academic Search

In this work, we compared the performance of a new method of cell immobilization in a novel matrix for biosorption. Yeast cells were entrapped in a polyvinyl alcohol (PVA) matrix, based on an adapted iterative freeze-thaw-freeze process. Spherical and uniform beads were produced, and SEM micrographs confirmed that the cells were uniformly dispersed within the PVA matrix. Further experiments revealed

Y. P. Ting; G. Sun

2000-01-01

291

Modification of cellulosic fabric using polyvinyl alcohol, Part-II: Colorfastness properties  

Microsoft Academic Search

A series of aqueous solutions of poly (vinyl alcohol) of various commercial products were prepared and applied onto the surfaces of cotton and blends of cotton\\/polyester fabrics. Fourier Transform Infrared spectrophotometer was used to confirm the molecular structure of the polyvinyl alcohol used. Performance tests such as colorfastness to rubbing (dry and wet) and colorfastness to washing were determined. The

Mohammad Zuber; Khalid Mahmood Zia; Ijaz Ahmad Bhatti; Tahir Jamil; Ali Rizwan

292

DSC and FTIR studies on Gellan and Polyvinyl alcohol (PVA) blend films  

Microsoft Academic Search

Homopolymer films of Gellan and polyvinyl alcohol (PVA) and blended films were prepared by a solution casting method from a polymer solution in water of Gellan and PVA using glycerol as plasticizer. The films were studied for thermal characteristics by differential scanning calorimetry, for intermolecular interactions by Fourier transform infrared spectroscopy and for the mechanical properties of tear strength, tensile

S. R Sudhamani; M. S Prasad; K Udaya Sankar

2003-01-01

293

Recent advances in starch, polyvinyl alcohol based polymer blends, nanocomposites and their biodegradability  

Microsoft Academic Search

Recent environmental regulations, societal concerns and growing environmental understanding throughout the world have triggered renewed efforts in plastic industry to develop new products and processes compatible with our environment. This review outlines the new developments in thermoplastic starch, polyvinyl alcohol based blends and nanocomposites. These materials show a broad and versatile range of physical properties and other advantageous characteristics at

Xiaozhi Tang; Sajid Alavi

2011-01-01

294

Mechanistic analysis of protein delivery from porous poly(vinyl alcohol) systems  

E-print Network

285 Mechanistic analysis of protein delivery from porous poly(vinyl alcohol) systems N.A. Peppas hydrogels are cross-linked networks of hydrophilic polymers that are used as versatile releasematerials is one of the few polymers that exhibit this phenomenon. Its crystalline regions serve as cross-linking

Peppas, Nicholas A.

295

In vivo calcium deposition on polyvinyl alcohol matrix used in hollow fiber cell macroencapsulation devices  

Microsoft Academic Search

The encapsulation of genetically modified cells represents a promising approach for the delivery of therapeutic proteins. The functionality of the device is dependent on the characteristics of the biomaterials, the procedures used in its confection and the adaptability of the encapsulated cells in the host. We report conditions leading to the development of calcifications on the polyvinyl alcohol (PVA) matrix

F. Schwenter; N. Bouche; W.-F. Pralong; P. Aebischer

2004-01-01

296

Assessment Guidelines for Managing Cellulose Acetate Collections  

NSDL National Science Digital Library

Photographic negatives, motion picture film, microfilm, and sound recordings produced from the 1930s into the 1950s often used cellulose acetate as the transparent plastic carrier. As anyone who has ever come in contact with it well knows, its strong vinegar-like scent is hard to miss. Unfortunately, over time, the material is prone to deterioration, which eventually renders it unusable. In an effort to help guide libraries in Australia with this problem, the National Library of Australia has created this document. It provides assistance in identification of cellulose acetate (vs. other similar materials) and establishes criteria to assess condition, cultural importance, and use within the library or storage context. The document guides readers through the first step in a strategy for preserving these collections.

2001-01-01

297

Leuprolide Acetate Suppresses Pedophilic Urges and Arousability  

Microsoft Academic Search

Cognitive–behavioral psychotherapy was compared with cognitive–behavioral psychotherapy augmented by leuprolide acetate (LA)\\u000a for suppression of pedophilic behavior. Five male pedophiles (M age, 50 years; range, 36–58) were administered LA by Depo injection for 12 months, followed by saline placebo for 12 months.\\u000a Testosterone levels, sexual interest preference by visual reaction time (Abel Assessment), penile tumescence (Monarch Penile\\u000a Plethysmography, PPG), as

Justine M. Schober; Phyllis J. Kuhn; Paul G. Kovacs; James H. Earle; Peter M. Byrne; Ruth A. Fries

2005-01-01

298

Interconversion studies of betamethasone acetate polymorphs.  

PubMed

The polymorph interconversions of Betamethasone Acetate (BA) were studied under various pharmaceutical conditions, such as grinding, heating and suspending in water, based on differential scanning calorimetry, thermogravimetric analysis, and X-ray powder diffraction. There existed enantiotropic relationships between the three polymorphs of BA, which were named form II, Ialpha, and Ibeta work, respectively. It was concluded that form II was the most stable form when suspended in water. PMID:16221616

Ke, Xue; Ping, QiNeng; Shi, Hua

2005-09-01

299

Corrosion of Stainless Steel During Acetate Production  

Microsoft Academic Search

Corrosion of types 304, 304L, 316, and 316L stainless steel (SS) during the esterification of acetic acid and alcohol or glycol ether was investigated. The catalyst for this reaction, sulfuric acid or para-toluene sulfonic acid (PTSA), was shown to cause more corrosion on reactor equipment than CHâCOOH under the process conditions commonly practiced in industry. The corrosive action of the

J. S. Qi; G. C. Lester

1996-01-01

300

Ulipristal acetate: the newest emergency contraceptive.  

PubMed

More than 50 percent of pregnancies in the United States are unplanned. Emergency contraception has been shown to possibly reduce the risk of pregnancy by as much as 75 percent. Ulipristal acetate is a selective progesterone receptor modulator that was approved by the U.S. Food and Drug Administration (FDA) for emergency contraceptive use in August 2010. This article reviews information on its mechanism of action, efficacy, safety and implications for women's health nurses. PMID:22900810

Wilton, Jeanne M

2012-01-01

301

Ultrasound-assisted dyeing of cellulose acetate.  

PubMed

The possibility of reducing the use of auxiliaries in conventional cellulose acetate dyeing with Disperse Red 50 using ultrasound technique was studied as an alternative to the standard procedure. Dyeing of cellulose acetate yarn was carried out by using either mechanical agitation alone, with and without auxiliaries, or coupling mechanical and ultrasound agitation in the bath where the temperature range was maintained between 60 and 80 °C. The best results of dyeing kinetics were obtained with ultrasound coupled with mechanical agitation without auxiliaries (90% of bath exhaustion value at 80 °C). Hence the corresponding half dyeing times, absorption rate constants according to Cegarra-Puente modified equation and ultrasound efficiency were calculated confirming the synergic effect of sonication on the dyeing kinetics. Moreover the apparent activation energies were also evaluated and the positive effect of ultrasound added to mechanical agitation was evidenced by the lower value (48 kJ/mol) in comparison with 112 and 169 kJ/mol for mechanical stirring alone with auxiliaries and without, respectively. Finally, the fastness tests gave good values for samples dyed with ultrasound technique even without auxiliaries. Moreover color measurements on dyed yarns showed that the color yield obtained by ultrasound-assisted dyeing at 80 °C of cellulose acetate without using additional chemicals into the dye bath reached the same value yielded by mechanical agitation, but with remarkably shorter time. PMID:24457001

Udrescu, C; Ferrero, F; Periolatto, M

2014-07-01

302

The clinical, histologic, and ultrastructural presentation of polyvinyl sponge (Ivalon) breast prostheses removed for massive fluid accumulation.  

PubMed

The current study describes what we believe is the first report of bilateral massive seromas associated with open-cell Ivalon sponges. Additionally, the gross, histologic, and ultrastructural features consistent with previous reports of polyvinyl alcohol prostheses are presented. Despite the reported chemical inertness of polyvinyl alcohol, this material may incite a biologic response in some patients, leading to dense fibrosis and occasional foreign-body giant-cell reaction. It is postulated that the molecular breakdown products of the polyvinyl alcohol polymer may create an osmotic gradient across the periprosthetic capsule, which may lead to intracapsular fluid accumulation, as presented in this case. PMID:10359261

Smith, A R; Garrison, J L; Greene, W B; Raso, D S

1999-06-01

303

Overview on mechanisms of acetic acid resistance in acetic acid bacteria.  

PubMed

Acetic acid bacteria (AAB) are a group of gram-negative or gram-variable bacteria which possess an obligate aerobic property with oxygen as the terminal electron acceptor, meanwhile transform ethanol and sugar to corresponding aldehydes, ketones and organic acids. Since the first genus Acetobacter of AAB was established in 1898, 16 AAB genera have been recorded so far. As the main producer of a world-wide condiment, vinegar, AAB have evolved an elegant adaptive system that enables them to survive and produce a high concentration of acetic acid. Some researches and reviews focused on mechanisms of acid resistance in enteric bacteria and made the mechanisms thoroughly understood, while a few investigations did in AAB. As the related technologies with proteome, transcriptome and genome were rapidly developed and applied to AAB research, some plausible mechanisms conferring acetic acid resistance in some AAB strains have been published. In this review, the related mechanisms of AAB against acetic acid with acetic acid assimilation, transportation systems, cell morphology and membrane compositions, adaptation response, and fermentation conditions will be described. Finally, a framework for future research for anti-acid AAB will be provided. PMID:25575804

Wang, Bin; Shao, Yanchun; Chen, Fusheng

2015-02-01

304

[Determination of 46 plasticizers in food contact polyvinyl chloride packaging materials and their migration into food simulants by gas chromatography-mass spectrometry].  

PubMed

A gas chromatography-mass spectrometry (GC-MS) method was developed for the determination of 46 plasticizers in food contact polyvinyl chloride (PVC) packaging materials and their migration into food simulants, i. e. water, 3% acetic acid, 10% ethanol and olive oil. Plasticizers in the PVC packaging materials, aqueous food simulants and olive oil food simulants were extracted by the dissolution-precipitation, liquid-liquid extraction and gel permeation chromatography (GPC) approaches, respectively. The extracts were analyzed by GC-MS in selective ion monitoring (SIM) mode and quantified using the external standard method. The cal-ibration curves were linear in the ranges of 0.1-2.0 mg/L with the correlation coefficients of 0.9910-0. 999 9. The limits of detection were from 0. 005 mg/kg to 0. 05 mg/kg ( S/N = 5 ). The recoveries at 3 spiked levels were 69.51%-107. 21% and the relative standard deviations (RSDs n = 6) ranged from 3.53% to 18.95%. These results show that this method is fast, sensitive and accurate for the qualitative and quantitative determination of plasticizers in food contact plastic products and 4 types of food simulants. PMID:21574398

Guo, Chunhai; Bo, Haibo; Duan, Wenzhong; Jia, Haitao; Chen, Ruichun; Ma, Yusong; Ai, Lianfeng

2011-01-01

305

Analysis of plasticizers in poly(vinyl chloride) medical devices for infusion and artificial nutrition: comparison and optimization of the extraction procedures, a pre-migration test step.  

PubMed

Medical devices (MDs) for infusion and enteral and parenteral nutrition are essentially made of plasticized polyvinyl chloride (PVC). The first step in assessing patient exposure to these plasticizers, as well as ensuring that the MDs are free from di(2-ethylhexyl) phthalate (DEHP), consists of identifying and quantifying the plasticizers present and, consequently, determining which ones are likely to migrate into the patient's body. We compared three different extraction methods using 0.1 g of plasticized PVC: Soxhlet extraction in diethyl ether and ethyl acetate, polymer dissolution, and room temperature extraction in different solvents. It was found that simple room temperature chloroform extraction under optimized conditions (30 min, 50 mL) gave the best separation of plasticizers from the PVC matrix, with extraction yields ranging from 92 to 100 % for all plasticizers. This result was confirmed by supplemented Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) and gravimetric analyses. The technique was used on eight marketed medical devices and showed that they contained different amounts of plasticizers, ranging from 25 to 36 % of the PVC weight. These yields, associated with the individual physicochemical properties of each plasticizer, highlight the need for further migration studies. PMID:25577357

Bernard, Lise; Cueff, Régis; Bourdeaux, Daniel; Breysse, Colette; Sautou, Valérie

2015-02-01

306

Formulation and characterization of modified release tablets containing isoniazid using swellable polymers.  

PubMed

The aim of this work was to develop swellable modified release (MR) isoniazid tablets using different combinations of polyvinyl acetate (PVAc) and sodium-carboxymethylcellulose (Na-CMC). Granules were prepared by moist granulation technique and then compressed into tablets. In vitro release studies for 12 hr were carried out in dissolution media of varying pH i.e. pH 1.2, 4.5, 7.0 and 7.5. Tablets of all formulations were found to be of good physical quality with respect to appearance (width and thickness), content uniformity, hardness, weight variation and friability. In vitro release data showed that increasing total polymer content resulted in more retarding effect. Formulation with 35% polymer content exhibited zero order release profile and it released 35% of the drug in first hr, later on, controlled drug release was observed upto the 12(th) hour. Formulations with PVAc to Na-CMC ratio 20:80 exhibited zero order release pattern at levels of studied concentrations, which suggested that this combination can be used to formulate zero order release tablets of water soluble drugs like isoniazid. Korsmeyer-Peppas modeling of drug release showed that non-Fickian transport is the primary mechanism of isoniazid release from PVAc and Na-CMC based tablets. The value of mean dissolution time decreased with the increase in the release rate of drug clearly showing the retarding behavior of the swellable polymers. The application of a mixture of PVAc to Na-CMC in a specific ratio may be feasible to formulate zero order release tablets of water soluble drugs like isoniazid. PMID:22468003

Akhtar, M F; Rabbani, M; Sharif, A; Akhtar, B; Saleem, A; Murtaza, G

2011-01-01

307

Acetate supplementation attenuates lipopolysaccharide-induced neuroinflammation  

PubMed Central

Glyceryl triacetate (GTA), a compound effective at increasing circulating and tissue levels of acetate was used to treat rats subjected to a continual 28 day intra-ventricular infusion of bacterial lipopolysaccharide (LPS). This model produces a neuroinflammatory injury characterized by global neuroglial activation and a decrease in choline acetyltransferase immunoreactivity in the basal forebrain. During the LPS infusion, rats were given a daily treatment of either water or GTA at a dose of 6g/kg by oral gavage. In parallel experiments free-CoA and acetyl-CoA levels were measured in microwave fixed brains and flash frozen heart, liver, kidney and muscle following a single oral dose of GTA. We found that a single oral dose of GTA significantly increased plasma acetate levels by 15 min and remained elevated for up to 4 hr. At 30 min the acetyl-CoA levels in microwave-fixed brain and flash frozen heart and liver were increased at least 2.2-fold. The concentrations of brain acetyl-CoA was significantly increased between 30 and 45 min following treatment and remained elevated for up to 4 hr. The concentration of free-CoA in brain was significantly decreased compared to controls at 240 min. Immunohistochemical and morphological analysis demonstrated that a daily treatment with GTA significantly reduced the percentage of reactive GFAP-positive astrocytes and activated CD11b-positive microglia by 40–50% in rats subjected to LPS-induced neuroinflammation. Further, in rats subjected to neuroinflammation, GTA significantly increased the number of ChAT-positive cells by 40% in the basal forebrain compared to untreated controls. These data suggest that acetate supplementation increases intermediary short chain acetyl-CoA metabolism and that treatment is potentially anti-inflammatory and neuroprotective with regards to attenuating neuroglial activation and increasing ChAT immunoreactivity in this model. PMID:21272004

Reisenauer, Chris J.; Bhatt, Dhaval P.; Mitteness, Dane J.; Slanczka, Evan R.; Gienger, Heidi M.; Watt, John A.; Rosenberger, Thad A.

2011-01-01

308

Effects of Concentration of Organically Modified Nanoclay on Properties of Sulfonated Poly(vinyl alcohol) Nanocomposite Membranes  

E-print Network

Electrolyte nanocomposite membranes for proton exchange membrane fuel cells and direct methanol fuel cells were prepared by carrying out a sulfonation of poly(vinyl alcohol) with sulfosuccinic acid and adding a type of ...

Sanglimsuwan, Apiradee

309

Infrared absorption and vibrational circular dichroism spectra of poly(vinyl ether) containing diastereomeric menthols as pendants  

Microsoft Academic Search

The absorption and vibrational circular dichroism (VCD) spectra in the 1700 to 830 cm?1 region are reported and qualitatively interpreted for poly(vinyl ether) with (+)-menthol (I), (+)-isomenthol (II) and (+)-neomenthol (III) as pendants.

Jennifer L. McCann; Arvi Rauk; Hal Wieser

1997-01-01

310

Crystal growth of calcium carbonate on the cellulose acetate/pyrrolidon blend films in the presence of L-aspartic acid  

NASA Astrophysics Data System (ADS)

The morphogenesis and growth process of calcium carbonate on the cellulose acetate/polyvinyl pyrrolidone (CA/PVP) blend films in the presence of L-aspartic acid was carefully investigated. The results showed that the concentration of L-aspartic acid, the initial pH value of reaction solution and temperature turned out to be important factors for the control of morphologies and polymorphs of calcium carbonate. Complex morphologies of CaCO3 particles, such as cubes, rose-like spheres, twinborn-spheres, cone-like, bouquet-like, etc. could be obtained under the different experimental conditions. The dynamic process of formation of rose-like sphere crystals was analyzed by monitoring the continuous morphological and structural evolution and components of crystals in different crystal stages. This research may provide a promising method to prepare other inorganic materials with complex morphologies.

Zhang, Xiuzhen; Xie, Anjian; Huang, Fangzhi; Shen, Yuhua

2014-03-01

311

Surface and Interfacial Structure of Release Coatings for Pressure Sensitive Adhesives I. Polyvinyl N-Alkyl Carbamates  

Microsoft Academic Search

Polyvinyl N-alkyl carbamates belong to the general class of long alkyl side chain polymers. Such polymers are commonly used as release coatings for pressure sensitive adhesive tapes. In this paper the bulk, surface, and interfacial structures of polyvinyl N-alkyl carbamates having either decyl or octadecyl side chains are examined. The bulk structures and thermal transitions were characterized using X-ray scattering

David J. Kinning

1997-01-01

312

Application of mixtures of polymeric carriers for dissolution enhancement of fenofibrate using hot-melt extrusion.  

PubMed

Hot-melt extrusion was applied to improve dissolution behavior of poorly soluble model drug fenofibrate. Blends of polymers were used as carrier: copovidone (COP), polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol copolymer (PVCL-PVAc-PEG) and hypromellose 2910/5 (HPMC). The ratio of fenofibrate to COP remained constantly 1+3 (weighted parts) with varying amounts of PVCL-PVAc-PEG and HPMC. Solid state of fenofibrate was characterized by X-ray diffractometry and differential scanning calorimetry. Dissolution performance was compared to marketed formulations Lipidil and Lipidil-Ter. Stability studies were conducted at 25°C/60%rH. The dissolution rate from extrudates was significantly increased when compared to pure fenofibrate powder or physical mixture of the components. A supersaturation of 7.6-12.1 was reached with the pelletized extrudates. All extrudates were superior to marketed formulations. No recrystallization was observed after 26 weeks of storage for fenofibrate-COP extrudates 1+3 (weighted parts) with or without polymeric additives. Even so, both degree and duration of supersaturation decreased with increasing storage periods with the exception of fenofibrate-HPMC extrudates. Of particular interest is the finding that by adding polymers with differing release characteristics to the drug-carrier mixture, the dissolution performance of hot-melt extruded solid dosage forms can be readily adapted to meet specific requirements. PMID:22440149

Kalivoda, Adela; Fischbach, Matthias; Kleinebudde, Peter

2012-06-15

313

Effect of Some Chemicals on Thermal Conductivity of Impregnated Laminated Veneer Lumbers Bonded with Poly(vinyl acetate) and Melamine–Formaldehyde Adhesives  

Microsoft Academic Search

Thermal conductivity is a very important parameter in determining heat transfer rate and is required for the development of drying models and for the industrial operations such as adhesive cure rate. The objective of this research was to investigate the effects of impregnation on the thermal conductivity of six-layered laminated veneer lumber (LVL) made of beech and pine. Boric acid,

Hamiyet ?ahin Kol; Suat Altun

2009-01-01

314

Immunotoxicity of trenbolone acetate in Japanese quail  

USGS Publications Warehouse

Trenbolone acetate is a synthetic androgen that is currently used as a growth promoter in many meat-exporting countries. Despite industry laboratories classifying trenbolone as nonteratogenic, data showed that embryonic exposure to this androgenic chemical altered development of the immune system in Japanese quail. Trenbolone is lipophilic, persistent, and released into the environment in manure used as soil fertilizer. This is the first study to date to assess this chemical's immunotoxic effects in an avian species. A one-time injection of trenbolone into yolks was administered to mimic maternal deposition, and subsequent effects on the development and function of the immune system were determined in chicks and adults. Development of the bursa of Fabricius, an organ responsible for development of the humoral arm of the immune system, was disrupted, as indicated by lower masse, and smaller and fewer follicles at day 1 of hatch. Morphological differences in the bursas persisted in adults, although no differences in either two measures of immune function were observed. Total numbers of circulating leukocytes were reduced and heterophil-lymphocyte ratios were elevated in chicks but not adults. This study shows that trenbolone acetate is teratogenic and immunotoxic in Japanese quail, and provides evidence that the quail immune system may be fairly resilient to embryonic endocrine-disrupting chemical-induced alterations following no further exposure posthatch.

Quinn, M.J.; McKernan, M.; Lavoie, E.T.; Ottinger, M.A.

2007-01-01

315

[Ulipristal acetate, 5mg: a new alternative].  

PubMed

Fibroids have a high prevalence (approaching 50%) in the female population. Although they are a benign entity, they represent a health problem of considerable magnitude, causing hemorrhaging, pain and sterility. Surgical treatment is currently safe and effective, but in recent decades numerous less invasive alternatives have appeared, such as uterine artery embolization and thermal ablation (HIFU and radiofrequency). New possibilities for medical treatment have also emerged, such as GnRh analogues, aromatase inhibitors and selective progesterone receptor modulators (SPRMs). SPRMs act through progesterone receptors and behave as agonists or antagonists in various target organs. Among them, ulipristal acetate (UA) inhibits the proliferation and induction of apoptosis and cell death pathways in leiomyoma cells, translating at the clinical level to smaller fibroids and lower uterine volumes, with no significant side effects. UA also produces amenorrhea in most patients. Randomized, phase III (PEARL I and II) clinical trials have shown the efficacy and security of UA versus placebo and leuprolide acetate (LA). UA is similar to LA, and superior to placebo in controlling bleeding and decreasing the size of the fibroid, with fewer side effects than LA. The safety and tolerance of UA have been satisfactory. UA is a reality in the preoperative treatment of fibroids, with broad potential for further development. PMID:24314567

Monleón Sancho, Javier; Romaguera, Eugenia; Romero, Ainhoa; Higueras, Gema; Morcillo, Inmaculada; Fuster, Sonia

2013-07-01

316

Phytogenic biosynthesis and emission of methyl acetate.  

PubMed

Acetylation of plant metabolites fundamentally changes their volatility, solubility and activity as semiochemicals. Here we present a new technique termed dynamic (13) C-pulse chasing to track the fate of C1-3 carbon atoms of pyruvate into the biosynthesis and emission of methyl acetate (MA) and CO2 . (13) C-labelling of MA and CO2 branch emissions respond within minutes to changes in (13) C-positionally labelled pyruvate solutions fed through the transpiration stream. Strong (13) C-labelling of MA emissions occurred only under pyruvate-2-(13) C and pyruvate-2,3-(13) C feeding, but not pyruvate-1-(13) C feeding. In contrast, strong (13) CO2 emissions were only observed under pyruvate-1-(13) C feeding. These results demonstrate that MA (and other volatile and non-volatile metabolites) derive from the C2,3 atoms of pyruvate while the C1 atom undergoes decarboxylation. The latter is a non-mitochondrial source of CO2 in the light generally not considered in studies of CO2 sources and sinks. Within a tropical rainforest mesocosm, we also observed atmospheric concentrations of MA up to 0.6 ppbv that tracked light and temperature conditions. Moreover, signals partially attributed to MA were observed in ambient air within and above a tropical rainforest in the Amazon. Our study highlights the potential importance of acetyl coenzyme A (CoA) biosynthesis as a source of acetate esters and CO2 to the atmosphere. PMID:23862653

Jardine, Kolby; Wegener, Frederik; Abrell, Leif; van Haren, Joost; Werner, Christiane

2014-02-01

317

Synthesis and characterization of polyvinyl alcohol based multiwalled carbon nanotube nanocomposites  

NASA Astrophysics Data System (ADS)

Multiwalled carbon nanotubes were synthesized by chemical vapor deposition over an Fe-Co/alumina catalyst. Nanotubes were then oxidized and grafted with polyvinyl alcohol (PVA). The obtained nanostructure was characterized by Raman spectroscopy, XRD, FTIR, EDX, SEM, TEM and TGA methods. FTIR confirmed the presence of the characteristic peaks of the anticipated ester group. The formation of polymer nanocomposites based on polyvinyl alcohol and multiwalled carbon nanotubes was confirmed by SEM and TEM. High resolution electron micrographs revealed that the primary binding sites for PVA grafting are the sidewall defects of the nanotubes. The novelty of this work is the use of the Fischer esterification reaction for creating the permanent link between the nanotubes and the PVA matrix.

Malikov, E. Y.; Muradov, M. B.; Akperov, O. H.; Eyvazova, G. M.; Puskás, R.; Madarász, D.; Nagy, L.; Kukovecz, Á.; Kónya, Z.

2014-07-01

318

In-situ cross linking of polyvinyl alcohol. [application to battery separator films  

NASA Technical Reports Server (NTRS)

A method of producing a crosslinked polyvinyl alcohol structure, such as a battery separator membrane or electrode envelope is described. An aqueous solution of a film-forming polyvinyl alcohol is admixed with an aldehyde crosslinking agent a basic pH to inhibit crosslinking. The crosslinking agent, perferably a dialdehyde such as glutaraldehyde, is used in an amount of from about 1/2 to about 20% of the theoretical amount required to crosslink all of the hydroxyl groups of the polymer. The aqueous admixture is formed into a desired physical shape, such as by casting a sheet of the solution. The sheet is then dried to form a self-supporting film. Crosslinking is then effected by immersing the film in aqueous acid solution. The resultant product has excellent properties for use as a battery separator.

Philipp, W. H.; Hsu, L. C.; Sheibley, D. W. (inventors)

1981-01-01

319

Plasticizer for poly(vinyl chloride) from cardanol as a renewable resource material  

Microsoft Academic Search

The present work is aimed to the preliminary analysis of the applicability of cardanol derivatives as renewable plasticizers for soft PVC. Two different plasticizers were studied, obtained by esterification of the cardanol hydroxyl group (cardanol acetate) and further epoxidation of the side chain double bonds (epoxidated cardanol acetate). Differential Scanning Calorimetry (DSC) was used to study the miscibility between PVC

A. Greco; D. Brunetti; G. Renna; G. Mele; A. Maffezzoli

2010-01-01

320

Acetate absorption and metabolism in the rabbit hindgut.  

PubMed Central

Acetate disappearance from the loops of the hindgut in the rabbit was evaluated by measuring variations in the concentration of acetate in caecocolonic loops and differences in the arterial and venous plasma. In vivo metabolism in gut and liver tissues was studied after introduction of (1-14C) acetate into caecocolonic loops. The rate of disappearance from the loops was quantitatively significant and showed little variation irrespective of the location in the hindgut. Hindgut tissue metabolised acetate and the intensity of the metabolism varied with the segment studied. The distal position of the gut showed by far the highest acetate uptake. Radioactivity was found in a certain number of free amino acids, organic acids, and sugars. Acetate was mainly converted into aspartate and glutamate. These can be considered as 'stock forms' which can be diverted either towards oxidative metabolism or towards protein synthesis. Images Fig. 1 PMID:4007603

Marty, J F; Vernay, M Y; Abravanel, G M

1985-01-01

321

Preparation of Colloidal Rhodium in Poly(vinyl Alcohol) by Reduction with Methanol  

Microsoft Academic Search

Refluxing of a solution of poly(vinyl alcohol) and rhodium(III) chloride in methanol-water gives a colloidal dispersion of rhodium which is an effective catalyst for hydrogenation of cyclohexene in methanol at 30°C under atmospheric hydrogen pressure. Formaldehyde is produced quantitatively with the reduction of rhodium(III) chloride to metallic rhodium. The rhodium particles in the colloidal dispersion are found to consist of

Hidefumi Hirai; Yukimichi Nakao; Naoki Toshima

1978-01-01

322

Influence of polymer additives on thermal decomposition and smoke emission of poly(vinyl chloride)  

Microsoft Academic Search

The influence of polymer additives and metal oxides on thermal decomposition and smoke suppression of poly(vinyl chloride) was investigated using a cone calorimeter at an incident heat flux of 25 kW m?2. Acrylate (acrylic K120N), chlorinated polyethylene, PVC-MC100 and polyethylene wax were used as polymer additives, and metal oxides including CuO, MoO3 and FeOOH as smoke suppressants. The experimental data

Bin Li

2003-01-01

323

Strain hardening behavior of lightweight hybrid polyvinyl alcohol (PVA) fiber reinforced cement composites  

Microsoft Academic Search

Experimental results on the strain hardening and multiple cracking behaviors of polyvinyl alcohol (PVA) fiber reinforced cementitious\\u000a composites under bending are reported in this paper. Different hybrid combinations of PVA fibers with different lengths and\\u000a volume fractions are considered to reinforce the mortar matrix. Among different hybrid combinations, the composite containing\\u000a 2% thicker PVA fibers of 12 mm length and 1%

Shaikh Faiz Uddin Ahmed; Hirozo Mihashi

2011-01-01

324

Swelling behavior of interpenetrating polymer network hydrogels composed of poly(vinyl alcohol) and chitosan  

Microsoft Academic Search

Interpenetrating polymer network (IPN) hydrogels composed of poly(vinyl alcohol) (PVA) and chitosan were prepared by UV irradiation. The characteristics of IPN hydrogels were investigated by swelling experiments, Fourier transform infrared (FT-IR) spectroscopy and differential scanning calorimetry (DSC). IPN hydrogels exhibited a relatively high swelling ratio in the range of 210–350% at 35°C. The swelling ratio of PVA\\/chitosan IPN hydrogels depended

Seon Jeong Kim; Sang Jun Park; Sun I. Kim

2003-01-01

325

Preparation and property of polyvinyl alcohol-based film embedded with gold nanoparticles  

Microsoft Academic Search

Gold nanoparticles were prepared by a simple heat-treated method using polyvinyl alcohol (PVA) as reducing and stabilizing\\u000a agent in this article. UV\\/Vis spectroscopy was used to monitor the preparation. The formation of a sharp band at ~530 nm in\\u000a the UV\\/Vis spectra and morphological characters revealed by transmission electron microscopy indicated the generation of Au\\u000a nanoparticles. The PVA film embedded with

Changmei Sun; Rongjun Qu; Chunnuan Ji; Yanfeng Meng; Chunhua Wang; Yanzhi Sun; Lingyan Qi

2009-01-01

326

Inhibition of nucleation and growth of ice by poly(vinyl alcohol) in vitrification solution  

Microsoft Academic Search

Control of ice formation is crucial in cryopreservation of biological substances. Successful vitrification using several additives that inhibit ice nucleation in vitrification solutions has previously been reported. Among these additives, here we focused on a synthetic polymer, poly(vinyl alcohol) (PVA), and investigated the effects of PVA on nucleation and growth of ice in 35% (w\\/w) aqueous 1,2-propanediol solution by using

Hai-Yan Wang; Takaaki Inada; Kunio Funakoshi; Shu-Shen Lu

2009-01-01

327

Miscibility and morphology of blends of poly(3-hydroxybutyrate) and poly(vinyl butyral)  

Microsoft Academic Search

The miscibility and morphology of blends of biodegradable poly(3-hydroxybutyrate) (PHB) and poly(vinyl butyral) (PVB) were studied by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). PHB is a semi-crystalline polymer while PVB can be regarded as a random copolymer containing vinyl butyral (VB) and vinyl alcohol (VA) units whose composition ratio can be systematically changed over a wide range.

Wenjie Chen; Donald J David; William J MacKnight; Frank E Karasz

2001-01-01

328

Assessing biodegradability of plastics based on poly(vinyl alcohol) and protein wastes  

Microsoft Academic Search

Research was conducted into biodegradability of mixed polymer films based on poly(vinyl alcohol), protein hydrolyzate (collagen hydrolyzate from wastes after chrome tanning) and glycerol in an aqueous aerobic environment. Evaluation of biodegradation was based on carbon dioxide produced in the gas phase. Pure PVAL was degraded by a current mixed culture for water-treatment (unadapted) only after an approx. 10-day lag

Jarom??r Hoffmann; Iveta ?ezn???ková; Jarmila Kozáková; Jan R?ži?ka; Pavol Alexy; Dušan Bakoš; Lenka Precnerová

2003-01-01

329

Relaxation phenomena in poly(vinyl alcohol)\\/fumed silica affected by interfacial water  

Microsoft Academic Search

Interaction of poly(vinyl alcohol) (PVA) with fumed silica was investigated in the gas phase and aqueous media using adsorption, broadband dielectric relaxation spectroscopy (DRS), thermally stimulated depolarization current (TSDC), infrared spectroscopy, thermal analysis, and one-pass temperature-programmed desorption (OPTPD) mass-spectrometry (MS) methods. PVA monolayer formation leads to certain textural changes in the system (after suspension and drying) because of strong hydrogen

V. M. Gun'ko; P. Pissis; A. Spanoudaki; V. I. Zarko; Y. M. Nychiporuk; L. S. Andriyko; E. V. Goncharuk; R. Leboda; J. Skubiszewska-Zi?ba; V. D. Osovskii; Y. G. Ptushinskii

2007-01-01

330

Chemical alteration of poly(vinyl fluoride) Tedlar by hyperthermal atomic oxygen  

Microsoft Academic Search

In this study the erosion of poly(vinyl fluoride) Tedlar by hyperthermal atomic oxygen (AO) has been examined using X-ray photoelectron spectroscopy (XPS). Initially the Tedlar film had F\\/C and O\\/C atom ratios of 0.45 and 0.11, which decrease to 0.018 and 0.04, respectively, after a 2-h exposure to a flux of 2 × 1015atoms\\/cm2s AO with an average kinetic energy

Gar B. Hoflund; Michael L. Everett

2005-01-01

331

Chemical alteration of poly(vinyl fluoride) Tedlar ® induced by exposure to vacuum ultraviolet radiation  

Microsoft Academic Search

In this study the chemical alteration of poly(vinyl fluoride) Tedlar® by vacuum ultraviolet radiation (VUV) (115–400nm) has been examined using X-ray photoelectron spectroscopy (XPS). The initial F\\/C atom ratio of 0.34 decreases to 0.17 after a 2-h exposure. The F\\/C atom ratio is further reduced to a steady-state value of approximately 0.04 after a 24-h exposure. Similarly, the O\\/C atom

Michael L. Everett; Gar B. Hoflund

2006-01-01

332

Vinyl chloride and polyvinyl chloride: Toxicology. (Latest citations from the Life Sciences Collection database). Published Search  

SciTech Connect

The bibliography contains citations concerning the toxicity of vinyl chloride and polyvinyl chloride following short- and long-term exposure. The citations explore how these compounds are metabolized and consider their carcinogenic and teratogenetic potential. Methodologies to quantitate their presence in atmospheric dust and body tissues are discussed. Occupational hazards are also noted.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

NONE

1995-12-01

333

Preparation of the poly(vinyl alcohol)/layered double hydroxide nanocomposite  

SciTech Connect

Intercalated nanocomposite based on Mg, Al layered double hydroxide (LDH) and poly(vinyl alcohol) (PVA) was prepared using exfoliation-adsorption technique, and characterized by X-ray diffraction and thermal gravimetric analysis. The results suggest that the intercalated species are formed via the re-aggregation of the delaminated LDH lamellar with the interlayer spacing 14.5 A, and the thermal stability of the nanocomposite improved compared with the original PVA.

Li Baoguang; Hu Yuan; Zhang Rui; Chen Zuyao; Fan Weicheng

2003-10-01

334

Carbon nanotubes for reinforcement of plastics? A case study with poly(vinyl alcohol)  

Microsoft Academic Search

This paper reports a 4.5 fold increase in the Young’s modulus of a semi-crystalline polymer, poly(vinyl alcohol), with the addition of carbon nanotubes. The importance of nanotube diameter is addressed with the production of four composite solutions with each solution containing carbon nanotubes of a specific diameter. Thin films were cast for tensile tests while Differential Scanning Calorimetry (DSC) measured

Kevin P. Ryan; Martin Cadek; Valeria Nicolosi; David Blond; Manuel Ruether; Gordon Armstrong; Harry Swan; Antonio Fonseca; Janos B. Nagy; Wolfgang K. Maser; Werner J. Blau; Jonathan N. Coleman

2007-01-01

335

Disruption of the protective properties of the polyvinyl chloride coating under the effect of microorganisms  

SciTech Connect

The presence of sulfate-reducing bacteria results in a reduction of the protective properties of polyvinyl chloride (PVC) film coatings. The authors examine the effect of other types of soil microorganisms. Investigations were carried out with the cultures of bacteria Pseudomonas fluorescens B-22 and fungus Aspergillus niger van Tieghem F-1119 which are almost always present in corrosion regions in the routes of transmission pipelines. The microorganisms were grown in a mineral medium with glucose (Ps. fluorescens) and sucrose (A. niger).

Mogil'nitskii, G.M.; Sagatelyan, R.T.; Kutishcheva, T.N.; Zhukova, S.V.; Kerimov, S.I.; Parfenova, T.B.

1987-09-01

336

Fiber mats of poly(vinyl alcohol)\\/silica composite via electrospinning  

Microsoft Academic Search

Fiber mats of organic–inorganic hybrids, poly(vinyl alcohol) (PVA)\\/silica composite thin fibers, in the diameter of 200–400 nm were prepared by electrospinning. The fiber mats were characterized by IR, XRD, DSC, and TGA. The results indicated that PVA was changed from semicrystalline to amorphous state because of the increase of silica content. SEM photograph showed that junctions and bundles of the

Changlu Shao; Hak-Yong Kim; Jian Gong; Bin Ding; Douk-Rae Lee; Soo-Jin Park

2003-01-01

337

Preparation and characterization of chitosan-hydroxybenzotriazole\\/polyvinyl alcohol blend nanofibers by the electrospinning technique  

Microsoft Academic Search

Nanofibers of a chitosan-hydroxybenzotriazole (CS-HOBt)\\/polyvinyl alcohol (PVA) blend were successfully prepared using electrospinning techniques. In this study, nanofibers were fabricated without the use of standard organic solvents or organic acids. CS was dissolved with HOBt in distilled water, and this solution of CS-HOBt (2wt%) with PVA (10wt%), blended in different weight ratios, was electrospun to obtain nanofibers. The morphology, diameter,

Natthan Charernsriwilaiwat; Praneet Opanasopit; Theerasak Rojanarata; Tanasait Ngawhirunpat; Pitt Supaphol

2010-01-01

338

On the electrospinning of poly(vinyl alcohol) nanofiber mats: A revisit  

Microsoft Academic Search

Electrospinning was used to fabricate mats of poly(vinyl alcohol) (PVA; Mw 5 72,000 Da, degree of hy- drolysis 97.5-99.5) nanofibers from PVA solutions in reverse osmotic water. The effects of solution concentra- tion, applied electrical potential, sonication, and collection distance on morphological appearance and diameters of the as-spun fiber mats as well as those of the individual fibers were carefully

Pitt Supaphol; Surawut Chuangchote

2008-01-01

339

Effect of Process Parameters on the Microstructural Characteristics of Electrospun Poly(Vinyl Alcohol) Fiber Mats  

Microsoft Academic Search

Fiber mats with average fiber diameter ranging between 80 and 250 nm of polyvinyl alcohol (PVA)\\/water solution having a concentration\\u000a of 4 wt.% have been prepared by electrospinning method. The influence of applied voltage, flow rate, and needle-to-collector\\u000a distance on the fiber morphology and diameters has been studied. Scanning electron microscopy and atomic force microscopy\\u000a are used to characterize the fibers. It

Sarabjit Singh; S. G. Lakshmi; M. Vijayakumar

2009-01-01

340

Effect of pH on electrospinning of poly(vinyl alcohol)  

Microsoft Academic Search

7 wt.% poly(vinyl alcohol) (PVA) solutions at various pH values from 2.0 to 12.9 were electrospun in order to investigate the effect of pH on the morphology and diameter of electrospun PVA. The average diameter of PVA fibers electrospun at pH 7.2 was 290 nm. Electrospun PVA fibers became straighter and finer with increasing pH under basic conditions, whereas the

Won Keun Son; Ji Ho Youk; Taek Seung Lee; Won Ho Park

2005-01-01

341

Some aspects of the ozone degradation of poly(vinyl alcohol)  

Microsoft Academic Search

Poly(vinyl alcohol) (PVAL) forms a strong hydrogen-bond complex with ozone. The interaction energy is of the order of 47.3kJ\\/mol as calculated from the blue shift undergone by the ozone absorption band in the UV after its complexation with PVAL. This fact may have many important practical implications in the application of PVAL in wastewater treatment both in terms of O3

Franco Cataldo; Giancarlo Angelini

2006-01-01

342

Study on the photo-Fenton degradation of polyvinyl alcohol in aqueous solution  

Microsoft Academic Search

The degradation of polyvinyl alcohol (PVA) by the photo-Fenton process was studied in laboratory scale, with aim of investigating the effect of process conditions on the polymer degradation rate. The experiments were based on a complete factorial design for the amounts of Fe(II) and H2O2 added to water solutions of PVA of different concentrations. The degradation rate of the organic

J. A. Giroto; R. Guardani; A. C. S. C. Teixeira; C. A. O. Nascimento

2006-01-01

343

Inorganic salts effect on the poly(vinyl alcohol) cryogels properties  

Microsoft Academic Search

Poly(vinyl alcohol) (PVA) is a polymer with exceptional properties such as water solubility, biodegradability, biocompatibility, non-toxicity and non-carcinogenity that possesses the capability to form hydrogels by chemical or physical methods 1-3 . Its applicability fields were widely broadened during the latest years due to the development of the medicine and the increase of the needs in new biomaterials, to the

Silvia Patachia; Claudia Florea; Christian Friedrich; Yi Thomann; Camelia Scarneciu

344

pH-sensitive poly(vinyl alcohol)\\/sodium carboxymethylcellulose hydrogel beads for drug delivery  

Microsoft Academic Search

A series of pH-sensitive hydrogel beads were prepared composed of poly(vinyl alcohol) (PVA) and sodium carboxymethylcellulose (CMC) by using Fe crosslinking and freeze-thawing (FT) cycle techniques. The mixed solution of CMC and PVA was firstly crosslinked with Fe to form beads and then subjected to freezing-thawing cycles for further crosslinking. The formation of hydrogel were confirmed by Fourier transform infrared

Shengjie Wang; Qian Zhang; Biwu Tan; Liying Liu; Linfeng Shi

2011-01-01

345

Entrapment of glucose oxidase in non-porous poly(vinyl chloride)  

Microsoft Academic Search

We have used solvent casting techniques to immobilise glucose oxidase (GOD) within unplasticised and plasticised poly(vinyl chloride) (PVC) matrices. The plasticisers studied were the cationic surfactant, tricaprylmethylammonium chloride (Aliquat 336s), the anionic surfactant bis(2-ethylhexyl) hydrogenphosphate (BEP) and the lipid, isopropylmyristate (IPM). The activity of the enzyme-membrane was tested by amperometric electrode. Changes in enzyme-membrane electrode response are rationalised on the

Subrayal M. Reddy; Pankaj Vadgama

2002-01-01

346

DNA\\/polyvinyl alcohol interpenetrating polymer network as stationary phase for thin layer chromatography  

Microsoft Academic Search

Natural DNA was introduced to thin layer chromatography (TLC) with an aim to separate chemicals like DNA-affinity compounds and enantiomers. By cross-linking polyvinyl alcohol (PVA) with glutaraldehyde (GA) and subsequent cross-linking DNA with a UV irradiation, a DNA\\/PVA interpenetrating polymer network (IPN) is formed and was used to coat the surface of the porous silica particles of the TLC. Three

XiangDong Liu; Tetsuro Kubo; HongYan Diao; Jonganurakkun Benjamas; Tomomi Yonemichi; Norio Nishi

2009-01-01

347

Blood compatibility of novel poly(?-glutamic acid)\\/polyvinyl alcohol hydrogels  

Microsoft Academic Search

Sodium poly(?-glutamic acid) (PGA), a water-soluble and biodegradable polypeptide, was reacted with polyvinyl alcohol (PVA) to form hydrogel without any chemical treatment. The gelation occurred probably due to physical cross-linking of polymer chains by interpenetrating hydrogen bonding. From the results of thermal analysis, PGA\\/PVA exhibited better thermal stability than native PVA. Although the swelling ratio decreased with the increase of

Wen-Ching Lin; Da-Guang Yu; Ming-Chien Yang

2006-01-01

348

?-Irradiation Effect on the Non-Cross-Linked and Cross-Linked Polyvinyl Alcohol Films  

Microsoft Academic Search

The non-cross-linked and cross-linked polyvinyl alcohol (PVA) films were prepared by the casting method then irradiated with gamma rays for various doses up to 300 kGy. The structure and characterization of PVA were determined by using Infrared spectroscopy (FTIR), ultraviolet spectroscopy (UV) and X-ray diffraction (XRD). Swelling behaviour was also investigated. Mechanical properties have been examined with respect to the absorbed

N. M. El-Sawy; M. B. El-Arnaouty; A. M. Abdel Ghaffar

2010-01-01

349

Polyvinyl alcohol cross-linked macroporous polymeric hydrogels: Structure formation and regularity investigation  

Microsoft Academic Search

A series of novel polyvinyl alcohol (PVA) hydrogels were synthesized by cross-linking of acrylate-modified PVA in aqueous solutions. Hydrogels were prepared at a temperature range ?7.5 to ?25°?, macromer concentration 4–12wt.%, and initiator concentration 0.4 to 1.6mg\\/ml. The swelling behavior of polymeric hydrogels in aqueous media with different pH and ionic strength values was investigated. It was shown that they

A. A. Artyukhov; M. I. Shtilman; A. N. Kuskov; L. I. Pashkova; A. M. Tsatsakis; ?. K. Rizos

2011-01-01

350

Swelling and Reswelling Characteristics of Cross-Linked Poly(vinyl alcohol)\\/Chitosan Hydrogel Film  

Microsoft Academic Search

Poly(vinyl alcohol) (PVA), hydrogel was prepared by using glutaraldehyde as a cross-linking agent. The blend semi-synthetic hydrogel film, consisting of PVA and chitosan, was prepared from a solvent-casting technique and characterized for their intermolecular interactions using infrared method. The swelling and reswelling behaviors, as well as mechanical properties of the synthetic and semi-synthetic gels were examined by weighing and tensile

Z. Abdeen

2011-01-01

351

Chemical reaction between polyvinyl alcohol and titanate coupling agent with x-ray photoelectron spectroscopy  

Microsoft Academic Search

The chemical reaction between polyvinyl alcohol (PVA) and tri (dioctylpyrophosphoryloxy) isopropyl titanate (NDZ-201) was studied using X-ray photoelectron spectroscopy (XPS). The results show that some C?OH functional groups of PVA react\\u000a with the titanate coupling agent to form CPVA?O?Ti?O?CPVA bond. The cross-linking of the PVA chains occurs through the formation of CPVA?O?Ti?O?CPVA bonds and produces a three dimensional hydrophobic polymer

Li Bei-xing; Zhang Wen-sheng

2003-01-01

352

Mixed photo-cross-linked polyvinyl alcohol and calcium-alginate gels for cell entrapment  

Microsoft Academic Search

Living cells may be immobilized by gel entrapment under very mild conditions. The ionotropic gelation of alginate with bivalent cations such as Ca2+, as well as photo-induced gelation of polyvinyl alcohol (PVA) bearing photosensitive stilbazolium (SbQ) groups, are procedures that are compatible with most bioactive materials. In the search for more stable and stronger alginate gel beads, experiments have been

S. Hertzberg; E. Moen; C. Vogelsang; K. Østgaard

1995-01-01

353

High flux ultrafiltration nanofibrous membranes based on polyacrylonitrile electrospun scaffolds and crosslinked polyvinyl alcohol coating  

Microsoft Academic Search

In this study, we demonstrated a high flux thin film nanofibrous composite (TFNC) membrane system based on polyacrylonitrile (PAN) electrospun scaffold coupled with a thin barrier layer of cross-linked polyvinyl alcohol (PVA). With carefully chosen structural parameters (i.e., a mid-layer PAN scaffold with porosity of about 85% and cross-linked PVA top coating with thickness of about 0.5?m), the demonstrated TFNC

Kyunghwan Yoon; Benjamin S. Hsiao; Benjamin Chu

2009-01-01

354

Electrospun single-walled carbon nanotube\\/polyvinyl alcohol composite nanofibers: structure property relationships  

Microsoft Academic Search

Polyvinyl alcohol (PVA) nanofibers and single-walled carbon nanotube (SWNT)\\/PVA composite nanofibers have been produced by electrospinning. An apparent increase in the PVA crystallinity with a concomitant change in its main crystalline phase and a reduction in the crystalline domain size were observed in the SWNT\\/PVA composite nanofibers, indicating the occurrence of a SWNT-induced nucleation crystallization of the PVA phase. Both

Minoo Naebe; Tong Lin; Mark P. Staiger; Liming Dai; Xungai Wang

2008-01-01

355

Nanoporous Nanocomposite Hydrogels Composed of Polyvinyl Alcohol and Na-montmorillonite  

Microsoft Academic Search

Polyvinyl alcohol nanoporous nanocomposite hydrogels containing various levels of Na-montmorillonite were prepared by a cyclic freezing-thawing technique. An exfoliated morphology of silicate layers was observed for the nanocomposite hydrogels. The uniaxial tensile test indicated that the tensile modulus and tensile strength of the nanocomposite hydrogels increased with increasing Na-montmorillonite content, while their elongation-at-break values decreased. The results showed that by

M. SIROUSAZAR; M. KOKABI; Z. M. HASSAN; A. R. BAHRAMIAN

2012-01-01

356

Improvement of Physicochemical Properties of Natural Rubber and Polyvinyl Alcohol Blends by Radiation Vulcanization  

Microsoft Academic Search

Variable compositions of natural rubber latex (NRL) and polyvinyl alcohol (PVA) have been blended. The contents of PVA in the blends were varied from 0.5 phr to 3.0 phr and the total solids contents of NRL was fixed to 50%. The blends were irradiated at different irradiation doses (0–20 kGy) in the presence of normal butylacrylate (n-BA). The permanent set; swelling ratio and

M. A. Haque; M. U. Ahmad; F. Akhtar; N. C. Dafader; M. E. Haque

2007-01-01

357

The use of polyvinyl alcohol glutaraldehyde antigen coated discs for laser induced fluorescence detection of plague  

Microsoft Academic Search

F1-antigen purified from Yersinia pestis was covalently linked to polyvinyl alcohol (PVA) glutaraldehyde cross-linked discs synthesized by acid catalysis. This derivative was incubated with fluorescein labeled antibody against F1-antigen and excited at 4880 Å by either an argon laser or a dye laser. The fluorescence was detected at 5200 Å. The appearance of the transition at 5200 Å was indicative

L. B. Carvalho; A. M. Araujo; A. M. P. Almeida; W. M. Azevedo

1996-01-01

358

A polyvinyl alcohol\\/ p-sulfonate phenolic resin composite proton conducting membrane  

Microsoft Academic Search

Membranes composed of poly(vinyl alcohol) (PVA) and a proton source polymer, sulfonated phenolic resin (s-Ph) displayed good proton conductivity of the order of 10?2Scm?1 at ambient temperatures. Upon cross-linking above 110°C, covalent links between the sulfonate groups of the phenolic resin and the hydroxyl groups of the PVA were established. Although this sacrificed certain sulfonate groups, the conductivity value was

Chien-Shun Wu; Fan-Yen Lin; Chih-Yuan Chen; Peter P. Chu

2006-01-01

359

Synthesis, characterization and in vitro antimicrobial activities of boron\\/starch\\/polyvinyl alcohol hydrogels  

Microsoft Academic Search

Starch\\/polyvinyl alcohol (PVA) hydrogel films (SF) and boron complexes of these hydrogels were synthesized with or without using glutaraldehyde as a cross-linking agent (SF-BA, SF-GA, SF-GA-BA) and characterized by using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscope (SEM) and X-ray diffraction analysis (XRD) methods. In the preparation of the hydrogels; glutaraldehyde (GA) was used as cross-linking

Elif Ant Bursali; Senem Coskun; Murat Kizil; Mürüvvet Yurdakoc

2011-01-01

360

Preparation, structure, and catalytic activity of aluminum chloride immobilized on cross-linked polyvinyl alcohol microspheres  

Microsoft Academic Search

Aluminum chloride was covalently bound to cross-linked polyvinyl alcohol (CPVA) microspheres, giving rise to polymer-supported Lewis acid catalysts CPVA-AlCl3 with a high loading (2.07mmol\\/g). Their chemical structures were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, atomic absorption spectrometry, and chemical analysis methods. The catalytic activity of CPVA-AlCl3 as well as the relationship between structure and activity was investigated

Zhanbin Wang; Baojiao Gao

2010-01-01

361

Trypsin immobilization on discs of polyvinyl alcohol glutaraldehyde\\/polyaniline composite  

Microsoft Academic Search

Discs of polyvinyl alcohol cross-linked with glutaraldehyde (PVAG) were synthesized and covered with polyaniline activated with glutaraldehyde (PANIG). Trypsin was covalently immobilized on this composite yielding a preparation containing 21.1 units per disc. The FT-IR spectra of the discs showed bands of PVA (3300cm?1, 2930cm?1 and 1440cm?1) and PANI (1594cm?1 and 1100cm?1). The best immobilization conditions were: trypsin concentration at

Samantha Salomão Caramori; Flaviana Naves de Faria; Miriam Pereira Viana; Kátia Flávia Fernandes; Luiz Bezerra Carvalho

2011-01-01

362

Preparation of PVP (polyvinyl pyrrolidone)\\/Ba-Sr hexaferrites via gel to crystalline method  

Microsoft Academic Search

Ba-M and Sr-M-type hexagonal ferrites have been prepared via a sol–gel route, and the effects of adding different amounts of polyvinyl pyrrolidone (PVP) into the sol solutions. The average crystallite, size, D and ?, was obtained as for Z13 = 22 ±2 nm and Z13–2 = 16±3 nm and for Z16 = 18±7 nm and Z16–2 = 17±5 nm by XRD. FT-IR and TG

Z. Durmus; A. Baykal; H. Sozeri; M. S. Toprak

2012-01-01

363

Electrodialytic Transport Properties of Anion-Exchange Membranes Prepared from Poly(vinyl alcohol) and Poly(vinyl alcohol-co-methacryloyl aminopropyl trimethyl ammonium chloride)  

PubMed Central

Random-type anion-exchange membranes (AEMs) have been prepared by blending poly(vinyl alcohol) (PVA) and the random copolymer-type polycation, poly(vinyl alcohol-co-methacryloyl aminopropyl trimethyl ammonium chloride) at various molar percentages of anion-exchange groups to vinyl alcohol groups, Cpc, and by cross-linking the PVA chains with glutaraldehyde (GA) solution at various GA concentrations, CGA. The characteristics of the random-type AEMs were compared with blend-type AEMs prepared in our previous study. At equal molar percentages of the anion exchange groups, the water content of the random-type AEMs was lower than that of the blend-type AEMs. The effective charge density of the random-type AEMs increased with increasing Cpc and reached a maximum value. Further, the maximum value of the effective charge density increased with increasing CGA. The maximum value of the effective charge density, 0.42 mol/dm3, was obtained for the random-type AEM with Cpc = 4.2 mol % and CGA = 0.15 vol %. A comparison of the random-type and blend-type AEMs with almost the same Cpc showed that the random-type AEMs had lower membrane resistance than the blend-type ones. The membrane resistance and dynamic transport number of the random-type AEM with Cpc = 6.0 mol % and CGA = 0.15 vol % were 4.8 ? cm2 and 0.83, respectively. PMID:24958543

Jikihara, Atsushi; Ohashi, Reina; Kakihana, Yuriko; Higa, Mitsuru; Kobayashi, Kenichi

2012-01-01

364

Mesophilic syntrophic acetate oxidation during methane formation in biogas reactors  

Microsoft Academic Search

The reaction pathway for the formation of methane from acetate was investigated in sludge from 13 different biogas reactors. By following the conversion of [2-14C]acetate and [14C]bicarbonate it was shown that methane formation by syntrophic acetate oxidation was the dominating mechanism for acetotrophic methanogenesis in sludge containing high levels of salts, mainly ammonium, and volatile fatty acids. In one biogas

Anna Schnürer; Gerhard Zellner; Bo H. Svensson

1999-01-01

365

Solution behavior and surface properties of carboxymethylcellulose acetate butyrate  

Microsoft Academic Search

Solution behavior of carboxymethylcellulose acetate butyrate (CMCAB) in acetone and ethyl acetate has been investigated by\\u000a small-angle X-ray scattering (SAXS) and capillary viscometry and correlated with the characteristics of CMCAB films. Viscosity\\u000a and SAXS measurements showed that ethyl acetate is a better solvent than acetone for CMCAB. Thin films of CMCAB were deposited\\u000a onto silicon wafers (Si\\/SiO2) by spin coating.

Jorge Amim Jr; Denise F. S. Petri; Francisco C. B. Maia; Paulo B. Miranda

2009-01-01

366

Evaluation of dimensional stability and accuracy of autoclavable polyvinyl siloxane impression material.  

PubMed

Dimensionally stable autoclavable impressions will be effective in controlling the cross-infection and contamination caused by patient's saliva and other oral secretions. The accuracy of newly introduced autoclavable polyvinyl siloxane impression material was assessed for its dimensional stability and accuracy. A standard metal model (Dentoform, U-501, Columbia) was customised for impression making. The impressions were made using the newly introduced polyvinyl siloxane impression materials (AFFINIS, Coltene/Whaledent AG, 9450 Alstalten, Switzerland). Fifty impressions were made and were divided into two groups A and B of 25 each. Group A was the control sample (non-autoclaved impressions) and group B was the test sample (autoclaved impressions), which was subjected to the steam autoclave procedure at 134 °C for 18 min, casts were poured in type IV gypsum products. The customised metal model, casts obtained from control and test group were subjected to laboratory evaluation with help of a travelling microscope (×10 magnification), and digital vernier calliper (0.01 mm/10 ?m accuracy). Data analysis was done using one-way ANOVA and One-Sample t test to evaluate the overall accuracy (P < 0.005). As a result, there was an average reduction of 0.016 ?m in overall dimension between the test and the control group when compared with the master model, which is not statistically or clinically significant. The newly introduced polyvinyl siloxane impression material is accurate and dimensional stable for clinical use when steam autoclaved at 134 °C for 18 min. PMID:24431790

Reddy, Subash M; Vijitha, D; Karthikeyan, S; Balasubramanian, R; Satish, A

2013-12-01

367

Downstream processing of acetate fermentation broths by nanofiltration  

Microsoft Academic Search

Acetate can be separated from fermentation broths and partially purified by nanofiltration (NF). Membrane performance was\\u000a a function of pressure, pH, concentration of acetate, temperature, and the presence of other media components. With Nitto-Denko’s\\u000a NTR729 membrane, average acetate rejection was 60%, glucose rejection was 99%, and flux was 15 L\\/m2\\/h at 200 psig, 30°C, pH 5.6, and 20 g\\/L acetic

In Soo Han; Munir Cheryan

1996-01-01

368

Study of the complexation of iron (III) and iron (II) with thioamidated copolymers based on polyvinyl alcohol and polyacrylonitrile by Moessbauer spectroscopy  

SciTech Connect

The mechanism of the interaction of iron(III) with polymeric ligands of vibrous structure, viz., polyvinyl alcohol (PVA), a copolymer of polyvinyl alcohol and polyacrylonitrile (PVA-PAN), and a thioamidated copolymer of polyvinyl alcohol and polyacrylonitrile (PVA-PAN-T), has been established by Moessbauer spectroscopy. It has been found that Fe(III) is partially or completely reduced to Fe(II) during sorption and that both forms of iron coordinate the oxygen-containing functional groups of the polymers.

Turte, K.I.; Yakubov, K.M.; Sokhibov, S.S.; Kalontarova, E.Ya.; Kalontarov, I.Ya.

1988-04-01

369

Ulipristal acetate: a new emergency contraceptive.  

PubMed

Ulipristal acetate (UPA) is a newly developed emergency contraceptive currently available in the USA and Europe. It is approved as a 30 mg one-time dose taken within 120 h (5 days) of unprotected intercourse or failed contraception. This selective progesterone receptor modulator appears to be more effective than the levonorgestrel-containing emergency contraceptive, which must be taken within 72 h of unprotected intercourse. According to pharmacodynamic trials, UPA delays follicular maturation and ovulation. In addition, UPA may modulate the endometrium. Both Phase III clinical trials found that UPA does not lose efficacy within the 120-h dosing interval. Throughout all phases of clinical studies, UPA was shown to be well tolerated with only minimal adverse drug reactions, all of which are similar to competitor therapies. PMID:22114852

Sullivan, Jade L; Bulloch, Marilyn N

2011-07-01

370

Oxidation of indole-3-acetic acid to oxindole-3-acetic acid by an enzyme preparation from Zea mays  

NASA Technical Reports Server (NTRS)

Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.

Reinecke, D. M.; Bandurski, R. S.

1988-01-01

371

Heterogeneous catalyst for the production of acetic anhydride from methyl acetate  

DOEpatents

This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

Ramprasad, Dorai (Allentown, PA); Waller, Francis Joseph (Allentown, PA)

1999-01-01

372

Heterogeneous catalyst for the production of acetic anhydride from methyl acetate  

DOEpatents

This invention relates to a process for producing acetic anhydride by the reaction of methyl acetate, carbon monoxide, and hydrogen at elevated temperatures and pressures in the presence of an alkyl halide and a heterogeneous, bifunctional catalyst that contains an insoluble polymer having pendant quaternized phosphine groups, some of which phosphine groups are ionically bonded to anionic Group VIII metal complexes, the remainder of the phosphine groups being bonded to iodide. In contrast to prior art processes, no accelerator (promoter) is necessary to achieve the catalytic reaction and the products are easily separated from the catalyst by filtration. The catalyst can be recycled for consecutive runs without loss in activity. Bifunctional catalysts for use in carbonylating dimethyl ether are also provided.

Ramprasad, D.; Waller, F.J.

1999-04-06

373

Subcutaneous Depot Medroxyprogesterone Acetate versus Leuprolide Acetate in the Treatment of Endometriosis-Associated Pain  

Microsoft Academic Search

BACKGROUND: A clinical study compared efficacy and safety of depot medroxyprogesterone acetate (DMPA) with leuprolide for endometriosis-associated pain. METHODS: This multicentre, 18 month, evaluator-blinded, comparator- controlled trial randomized 300 women with laparoscopically diagnosed endometriosis to 6 month treatment with subcutaneous injection of 104 mg\\/0.65 ml DMPA (DMPA-SC 104) every 3 months or leuprolide (3.75 mg monthly or 11.25 mg every

P. G. Crosignani; A. Luciano; A. Ray; A. Bergqvist

2006-01-01

374

Modification of textile acetate yarn with polyethylene oxide  

Microsoft Academic Search

Small proportions of polyethylene oxides are known to exert a modifying effect on acetate fibre when added to the common solvent. In the case of textile yarn the effect is optimum (improved fatigue strength) when the polymer solution contains I 2% polyethylene oxide (PEO) of a molecular weight of 4000 - 5000 \\/I\\/. Several batches of modified textile acetate yarn

M. Sh. Tairov; M. V. Polovnikova; D. I. Kalandarov; P. I. Baboshkin; Z. Z. Gulombaev; A. A. Saidov

1975-01-01

375

Transition-Metal-Catalyzed Carbonylation of Methyl Acetate.  

ERIC Educational Resources Information Center

Presents a study of the rhodium-catalyzed, ioding-promoted carbonylation of methyl acetate. This study provides an interesting contrast between the carbonylation of methyl acetate and the carbonylation of methanol when similar rhodium/iodine catalyst systems are used. (JN)

Polichnowski, S. W.

1986-01-01

376

Characterization of acetic acid bacteria in “traditional balsamic vinegar”  

Microsoft Academic Search

This study evaluated the glucose tolerance of acetic acid bacteria strains isolated from Traditional Balsamic Vinegar. The results showed that the greatest hurdle to acetic acid bacteria growth is the high sugar concentration, since the majority of the isolated strains are inhibited by 25% of glucose. Sugar tolerance is an important technological trait because Traditional Balsamic Vinegar is made with

Maria Gullo; Cinzia Caggia; Luciana De Vero; Paolo Giudici

2006-01-01

377

Asymmetric Hydrogenation of Itaconic Acid and Enol Acetate Derivatives with  

E-print Network

. A variety of chiral 2-substituted succinic acids and chiral acetates have been obtained in excellent ee)- acrylates.3b Herein we report the applications of TangPhos in asymmetric hydrogenation of itaconic acid of acyclic enol acetates bearing aromatic substituents. Chiral 2-substituted succinic acids have attracted

Zhang, Xumu

378

Original article Ethanol and acetic-acid tolerances  

E-print Network

Original article Ethanol and acetic-acid tolerances in Drosophila melanogaster: similar maternal) Summary - Ethanol and acetic-acid tolerances were studied in a cross between 2 geo- graphic races disappeared in the F2. Further investigations demonstrated that for ethanol tolerance, the large difference

Paris-Sud XI, Université de

379

Gas-phase properties and reactivity of the acetate radical anion. Determination of the CH bond strengths in acetic acid and acetate ion  

Microsoft Academic Search

The acetate radical anion, CH[sub 2]CO[sub 2] [sup [center dot]-], has been generated in the gas phase at room temperature and its thermochemical properties and reactivity have been examined with use of a flowing afterglow-triple quadrupole instrument. This ion is formed in high yield from the reaction between F[sub 2] and the enolate ions of either acetic acid or trimethylsilyl

Paul G. Wenthold; Robert R. Squires

1994-01-01

380

The utilisation of glucose\\/acetate mixtures by Escherichia coli W3110 under aerobic growth conditions  

Microsoft Academic Search

Byproduct acetate is of major concern when considering the growth of Escherichia coli on glucose. Besides the fact that acetate production detracts from the overall yield, acetate itself is also a growth inhibitor. To further complicate matters, E. coli is capable of growth on acetate via the glyoxylate bypass. In an effort to evaluate the influence of acetate on the

D. O'Beirne; G. Hamer

2000-01-01

381

Polymer coating of paramagnetic particulates for in vivo oxygen-sensing applications  

PubMed Central

Crystalline lithium phthalocyanine (LiPc) can be used to sense oxygen. To enhance biocompatibility/stability of LiPc, we encapsulated LiPc in Teflon AF (TAF), cellulose acetate (CA), and polyvinyl acetate (PVAc) (TAF, previously used to encapsulate LiPc, was a comparator). We identified water-miscible solvents that don’t dissolve LiPc crystals, but are solvents for the polymers, and encapsulated crystals by solvent evaporation. Oxygen sensitivity of films was characterized in vitro and in vivo. Encapsulation did not change LiPc oximetry properties in vitro at anoxic conditions or varying partial pressures of oxygen (pO2). EPR linewidth of encapsulated particles was linear with pO2, responding to pO2 changes quickly and reproducibly for dynamic measurements. Encapsulated LiPc was unaffected by biological oxidoreductants, stable in vivo for four weeks. Oximetry, stability and biocompatibility properties of LiPc films were comparable, but both CA and PVAc films are cheaper, and easier to fabricate and handle than TAF films, making them superior. PMID:19083100

Eteshola, Edward; Pandian, Ramasamy P.; Kuppusamy, Periannan

2009-01-01

382

Supercritical water oxidation of polyvinyl alcohol and desizing wastewater: influence of NaOH on the organic decomposition.  

PubMed

Polyvinyl alcohol is a refractory compound widely used in industry. Here we report supercritical water oxidation of polyvinyl alcohol solution and desizing wastewater with and without sodium hydroxide addition. However, it is difficult to implement complete degradation of organics even though polyvinyl alcohol can readily crack under supercritical water treatment. Sodium hydroxide had a significant catalytic effect during the supercritical water oxidation of polyvinyl alcohol. It appears that the OH- ion participated in the C-C bond cleavage of polyvinyl alcohol molecules, the CO2-capture reaction and the neutralization of intermediate organic acids, promoting the overall reactions moving in the forward direction. Acetaldehyde was a typical intermediate product during reaction. For supercritical water oxidation of desizing wastewater, a high destruction rate (98.25%) based on total organic carbon was achieved. In addition, cases where initial wastewater was alkaline were favorable for supercritical water oxidation treatment, but salt precipitation and blockage issues arising during the process need to be taken into account seriously. PMID:24520696

Zhang, Jie; Wang, Shuzhong; Guo, Yang; Xu, Donghai; Gong, Yanmeng; Tang, Xingying

2013-08-01

383

Conducting polymer blends: Polypyrrole and polythiophene blends with polystyrene, polycarbonate resin, poly(vinyl alcohol) and poly(vinyl methyl ketone)  

SciTech Connect

Various aromatic compounds can be polymerized by electrochemical oxidation in solution containing a supporting electrolyte. Most studies have been devoted to polypyrrole and polythiophene. In situ doping during electrochemical polymerization yields free standing conductive polymer film. One major approach to making conducting polymer blends is electrochemical synthesis after coating the host polymer on a platinum electrode. In the electrolysis of pyrrole or thiophene monomer, using (t-Bu[sub 4]N)BF[sub 4] as supporting electrolyte, and acetonitrile as solvent, monomer can diffuse through the polymer film, to produce a polypyrrole or polythiophene blend in the film. Doping occurs along with polymerization to form a conducting polymer alloy. The strongest molecular interaction in polymers, and one that is central to phase behavior, is hydrogen bonding. This mixing at the molecular level enhances the degree of miscibility between two polymers and results in macroscopic properties indicative of single phase behavior. In this dissertation, the authors describes the syntheses of conducting polymer blends: polypyrrole and polythiophene blends with polystyrene, poly(bisphenol-A-carbonate), polyvinyl alcohol and poly(vinyl methyl ketone). The syntheses are performed both electrochemically and chemically. Characterization of these blends was carried out by Fourier Transform Infrared spectroscopy, Differential Scanning Calorimetry, Thermogravimetric Analysis, Scanning Electron Microscopy, and X-ray diffraction. Percolating threshold conductivities occur from 7% to 20% for different polymer blends. The low threshold conductivity is attributed to blend homogeneity enhanced by hydrogen bonding between the carbonyl group in the insulating polymer and the N-H group in polypyrrole. Thermal stability, environmental stability, mechanical properties, crystallinity and morphological structure are also discussed. The authors have also engaged in the polymerization of imidazoles.

Wang, H.L.

1992-01-01

384

Diffusion of benzocaine in poly(ethylene-vinyl acetate) membranes: Effects of vehicle ethanol concentration and membrane vinyl acetate content  

Microsoft Academic Search

The effect of vehicle ethanol concentration and membrane vinyl acetate (VA) content on the diffusion properties of poly (ethylene-vinyl acetate) (EVA) membranes was studied. The maximum flux of a model drug, benzocaine, through EVA membranes increases with increasing ethanol concentration and membrane VA content. The flux enhancement is attributed to the increases of both benzocaine membrane solubility and diffusivity. For

Shirlynn X. Chen; Richard T. Lostritto

1996-01-01

385

The effect of oral sodium acetate administration on plasma acetate concentration and acid-base state in horses  

PubMed Central

Aim Sodium acetate (NaAcetate) has received some attention as an alkalinizing agent and possible alternative energy source for the horse, however the effects of oral administration remain largely unknown. The present study used the physicochemical approach to characterize the changes in acid-base status occurring after oral NaAcetate/acetic acid (NAA) administration in horses. Methods Jugular venous blood was sampled from 9 exercise-conditioned horses on 2 separate occasions, at rest and for 24 h following a competition exercise test (CET) designed to simulate the speed and endurance test of 3-day event. Immediately after the CETs horses were allowed water ad libitum and either: 1) 8 L of a hypertonic NaAcetate/acetic acid solution via nasogastric tube followed by a typical hay/grain meal (NAA trial); or 2) a hay/grain meal alone (Control trial). Results Oral NAA resulted in a profound plasma alkalosis marked by decreased plasma [H+] and increased plasma [TCO2] and [HCO3-] compared to Control. The primary contributor to the plasma alkalosis was an increased [SID], as a result of increased plasma [Na+] and decreased plasma [Cl-]. An increased [Atot], due to increased [PP] and a sustained increase in plasma [acetate], contributed a minor acidifying effect. Conclusion It is concluded that oral NaAcetate could be used as both an alkalinizing agent and an alternative energy source in the horse. PMID:18096070

Waller, Amanda; Lindinger, Michael I

2007-01-01

386

Micelles Protect and Concentrate Activated Acetic Acid  

NASA Astrophysics Data System (ADS)

As more and more exoplanets are discovered and the habitability of such planets is considered, one can turn to searching for the origin of life on Earth in order to better understand what makes a habitable planet. Activated acetic acid, or methyl thioacetate, has been proposed to be central to the origin of life on Earth, and also as an important energy currency molecule in early cellular evolution. We have investigated the hydrolysis of methyl thioacetate under various conditions. Its uncatalyzed rate of hydrolysis is about three orders of magnitude faster (K = 0.00663 s^-1; 100°C, pH 7.5, concentration = 0.33mM) than published rates for its catalyzed production making it unlikely to accumulate under prebiotic conditions. However, we also observed that methyl thioacetate was protected from hydrolysis when inside its own hydrophobic droplets. We found that methyl thioacetate protection from hydrolysis was also possible in droplets of hexane and in the membranes of nonanoic acid micelles. Thus, the hydrophobic regions of prebiotic micelles and early cell membranes could have offered a refuge for this energetic molecule increasing its lifetime in close proximity to the reactions for which it would be needed. Methyl thioacetate could thus be important for the origin of life on Earth and perhaps for better understanding the potential habitability of other planets.

Todd, Zoe; House, C.

2014-01-01

387

Biodegradable cellulose acetate nanofiber fabrication via electrospinning.  

PubMed

Nanofiber manufacturing is one of the key advancements in nanotechnology today. Over the past few years, there has been a tremendous growth of research activities to explore electrospinning for nanofiber formation from a rich variety of materials. This quite simple and cost effective process operates on the principle that the solution is extracted under the action of a high electric field. Once the voltage is sufficiently high, a charged jet is ejected following a complicated looping trajectory. During its travel, the solvent evaporates leaving behind randomly oriented nanofibers accumulated on the collector. The combination of their nanoscale dimensionality, high surface area, porosity, flexibility and superior strength makes the electrospun fibers suitable for several value-added applications, such as filters, protecting clothes, high performance structures and biomedical devices. In this study biodegradable cellulose acetate (CA) nanofibrous membranes were produced using electrospinning. The device utilized consisted of a syringe equipped with a metal needle, a microdialysis pump, a high voltage supply and a collector. The morphology of the yielded fibers was determined using SEM. The effect of various parameters, including electric field strength, tip-to-collector distance, solution feed rate and composition on the morphological features of the electrospun fibers was examined. The optimum operating conditions for the production of uniform, non-beaded fibers with submicron diameter were also explored. The biodegradable CA nanofiber membranes are suitable as tissue engineering scaffolds and as reinforcements of biopolymer matrix composites in foils by ultrasonic welding methods. PMID:21133179

Christoforou, Theopisti; Doumanidis, Charalabos

2010-09-01

388

Eslicarbazepine acetate (BIA 2-093).  

PubMed

Eslicarbazepine acetate (ESL) [(S)-(--)-10-acetoxy-10,11-dihydro-5H-dibenz[b,f]azepine-5-carboxamide], formerly known as BIA 2-093, is a novel central nervous system (CNS)-active compound with anticonvulsant activity. It behaves as a voltage-gated sodium channel (VGSC) blocker and is currently under clinical development for the treatment of epilepsy and bipolar disorder. ESL shares with carbamazepine and oxcarbazepine the dibenzazepine nucleus bearing the 5-carboxamide substitute, but is structurally different at the 10,11-position. This molecular variation results in differences in metabolism, preventing the formation of toxic epoxide metabolites such as carbamazepine-10,11 epoxide. In pharmacokinetic studies in humans, ESL was rapidly and extensively metabolized to eslicarbazepine (S-licarbazepine), which is responsible for pharmacological activity. ESL has been tested in patients with refractory partial-onset seizures and was found to be efficacious and well tolerated. Monotherapy studies in adult epileptic patients and add-on studies in epileptic children are in the planning process. The efficacy and safety data appear to be very promising considering the refractory nature of the epileptic population enrolled in studies to date. Results of ongoing phase III studies in adult epileptic patients are expected to be available in 2007 and are required to define the position of ESL in the therapy of patients with epilepsy. PMID:17199020

Almeida, Luis; Soares-da-Silva, Patrício

2007-01-01

389

Emergency contraception: potential role of ulipristal acetate  

PubMed Central

Unintended pregnancy is a global reproductive health problem. Emergency contraception (EC) provides women with a safe means of preventing unwanted pregnancies after having unprotected intercourse. While 1.5 mg of levonorgestrel (LNG) as a single dose or in 2 doses with 12 hours apart is the currently gold standard EC regimen, a single dose of 30 mg ulipristal acetate (UPA) has recently been proposed for EC use up to 120 hours of unprotected intercourse with similar side effect profiles as LNG. The main mechanism of action of both LNG and UPA for EC is delaying or inhibiting ovulation. However, the ‘window of effect’ for LNG EC seems to be rather narrow, beginning after selection of the dominant follicular and ending when luteinizing hormone peak begins to rise, whereas UPA appears to have a direct inhibitory effect on follicular rupture which allows it to be also effective even when administered shortly before ovulation, a time period when use of LNG is no longer effective. These experimental findings are in line with results from a series of clinical trials conducted recently which demonstrate that UPA seems to have higher EC efficacy compared to LNG. This review summarizes some of the data available on UPA used after unprotected intercourse with the purpose to provide evidence that UPA, a new type of second-generation progesterone receptor modulator, represents a new evolutionary step in EC treatment. PMID:21072297

Gemzell-Danielsson, Kristina; Meng, Chun-Xia

2010-01-01

390

Emergency contraception: potential role of ulipristal acetate.  

PubMed

Unintended pregnancy is a global reproductive health problem. Emergency contraception (EC) provides women with a safe means of preventing unwanted pregnancies after having unprotected intercourse. While 1.5 mg of levonorgestrel (LNG) as a single dose or in 2 doses with 12 hours apart is the currently gold standard EC regimen, a single dose of 30 mg ulipristal acetate (UPA) has recently been proposed for EC use up to 120 hours of unprotected intercourse with similar side effect profiles as LNG. The main mechanism of action of both LNG and UPA for EC is delaying or inhibiting ovulation. However, the 'window of effect' for LNG EC seems to be rather narrow, beginning after selection of the dominant follicular and ending when luteinizing hormone peak begins to rise, whereas UPA appears to have a direct inhibitory effect on follicular rupture which allows it to be also effective even when administered shortly before ovulation, a time period when use of LNG is no longer effective. These experimental findings are in line with results from a series of clinical trials conducted recently which demonstrate that UPA seems to have higher EC efficacy compared to LNG. This review summarizes some of the data available on UPA used after unprotected intercourse with the purpose to provide evidence that UPA, a new type of second-generation progesterone receptor modulator, represents a new evolutionary step in EC treatment. PMID:21072297

Gemzell-Danielsson, Kristina; Meng, Chun-Xia

2010-01-01

391

Chemical Leucoderma Induced by Ear-ring Stoppers Made of Polyvinyl Chloride  

PubMed Central

We report a case of chemical leucoderma (CL) in a 15-year-old girl, who developed patterned depigmentation at the back of both ear lobules after contact with plastic ear-ring stoppers made of polyvinyl chloride (PVC) after continuous use for 6–7 months. Patch test with Indian standard series and cosmetic series was negative after 48 h, but she refused patch testing for extended duration as the possibility of induced depigmentation at the test site was unacceptable to her. To the best of our knowledge, this is the first report of plastic ear-ring stopper induced CL. PMID:23060712

Sharma, Reena; Singal, Archana; Verma, Prashant; Grover, Chander

2012-01-01

392

Study of polyvinyl alcohol nanofibrous membrane by electrospinning as a magnetic nanoparticle delivery approach  

NASA Astrophysics Data System (ADS)

Electrospinning technique was used to fabricate polyvinyl alcohol (PVA)-based magnetic biodegradable nanofibers. PVA solution was mixed with ferrofluid or magnetic nanoparticles (MNPs) powder and formed two individual nanofibrous membranes (PVA/ferrofluid and PVA/MNPs powder) by electrospinning. The surface morphology of the nanofibrous membrane was characterized by scanning electron microscopy and the magnetic properties were measured by vibrating sample magnetometer. Macrophages (RAW 264.7) were co-cultured with the nanofibrous membranes for 12, 24, and 48 h and exhibited good cell viability (>95%). Results showed that the PVA fibers would be degraded and the embedded Fe3O4 nanoparticles would be released and delivered to cells.

Ger, Tzong-Rong; Huang, Hao-Ting; Huang, Chen-Yu; Hu, Keng-Shiang; Lai, Jun-Yang; Chen, Jiann-Yeu; Lai, Mei-Feng

2014-05-01

393

Flexible polyvinyl chloride neutron guides for transporting ultracold and very cold neutrons  

SciTech Connect

The transmission of ultracold neutrons (UCNs) through flexible polyvinyl chloride (PVC) tubes with lengths of up to 3 m and an internal diameter of 6-8 mm has been studied. High UCN transmission is found even for arbitrarily bent tubes (single bend, double bend, triple bend, figure eight, etc.). The transmission can be improved significantly by coating the inner surface of the tube with a thin layer of liquid fluorine polymer. The prospects of these neutron guides in fundamental and applied research are discussed.

Arzumanov, S. S., E-mail: sarzumanov@yandex.ru; Bondarenko, L. N. [Russian Research Center Kurchatov Institute (Russian Federation); Geltenbort, P. [Institut Laue-Langevin (France); Morozov, V. I. [Russian Research Center Kurchatov Institute (Russian Federation); Nesvizhevsky, V. V. [Institut Laue-Langevin (France); Panin, Yu. N.; Strepetov, A. N.; Chuvilin, D. Yu. [Russian Research Center Kurchatov Institute (Russian Federation)

2011-12-15

394

Role of metal oxides in the thermal degradation of poly(vinyl chloride)  

SciTech Connect

Thermal degradation of poly(vinyl chloride) has been studied in the presence of metal oxides by a thermogravimetric method. It follows a two-step mechanism. In the first step chlorine free radical is formed as in the case of pure PVC, and in the second step chlorine free radical replaces oxygen from metal oxide to form metal chloride and oxygen free radical. Subsequently, the oxygen free radical abstracts hydrogen from PVC. Formation of metal chloride is the rate-controlling step. The metal chlorides formed during the thermal degradation either volatilize or decompose simultaneously to lower metallic chlorides depending on the boiling point or the volatilization temperature.

Gupta, M.C.; Viswanath, S.G. [Nagpur Univ. (India)] [Nagpur Univ. (India)

1998-07-01

395

Preparation and characterization of poly(vinyl alcohol)/graphene nanofibers synthesized by electrospinning  

NASA Astrophysics Data System (ADS)

We report on the synthesis and characterization of electrospun polyvinyl alcohol (PVA)/graphene nanofibers. The samples produced were characterized by Raman spectroscopy for structural and defect density analysis, scanning electron microscopy (SEM) for morphological analysis, and thermogravimetric (TGA) for thermal analysis. SEM measurements show uniform hollow PVA fibers formation and excellent graphene dispersion within the fibers, while TGA measurements show the improved thermal stability of PVA in the presence of graphene. The synthesized polymer reinforced nanofibers have potential to serve in many different applications such as thermal management, supercapacitor electrodes and biomedical materials for drug delivery.

Barzegar, Farshad; Bello, Abdulhakeem; Fabiane, Mopeli; Khamlich, Saleh; Momodu, Damilola; Taghizadeh, Fatemeh; Dangbegnon, Julien; Manyala, Ncholu

2015-02-01

396

Polyvinyl alcohol-cellulose nanofibrils-graphene oxide hybrid organic aerogels.  

PubMed

Hybrid organic aerogels consisting of polyvinyl alcohol (PVA), cellulose nanofibrils (CNFs), and graphene oxide nanosheets (GONSs) were prepared using an environmentally friendly freeze-drying process. The material properties of these fabricated aerogels were measured and analyzed using various characterization techniques including compression testing, scanning electron microscopy, thermogravimetric (TGA) analysis, Brunauer-Emmet-Teller (BET) surface area analysis, and contact angle measurements. These environmentally friendly, biobased hybrid organic aerogels exhibited a series of desirable properties including a high specific compressive strength and compressive failure strain, ultralow density and thermal conductivity, good thermal stability, and moisture resistance, making them potentially useful for a broad range of applications including thermal insulation. PMID:23789837

Javadi, Alireza; Zheng, Qifeng; Payen, Francois; Javadi, Abdolreza; Altin, Yasin; Cai, Zhiyong; Sabo, Ronald; Gong, Shaoqin

2013-07-10

397

White-light emission of polyvinyl alcohol/ZnO hybrid nanofibers prepared by electrospinning  

NASA Astrophysics Data System (ADS)

Polyvinyl alcohol/ZnO (PVA/ZnO) hybrid nanofibers were prepared by the electrospinning technique. The structural and spectral information of the nanofibers was characterized by scanning electron microscopy, x-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, resonant Raman, and photoluminescence (PL). The results indicate that ZnO were successfully embedded in the one-dimensional hybrid fibers via chemical interactions between ZnO and PVA. PL results show the PVA/ZnO nanofibers have an intense white-light emission, which originates from the simultaneous emission of three bands covering from the UV to visible range. A possible PL mechanism was proposed accordingly.

Sui, X. M.; Shao, C. L.; Liu, Y. C.

2005-09-01

398

Monitoring of Temperature Fatigue Failure Mechanism for Polyvinyl Alcohol Fiber Concrete Using Acoustic Emission Sensors  

PubMed Central

The applicability of acoustic emission (AE) techniques to monitor the mechanism of evolution of polyvinyl alcohol (PVA) fiber concrete damage under temperature fatigue loading is investigated. Using the temperature fatigue test, real-time AE monitoring data of PVA fiber concrete is achieved. Based on the AE signal characteristics of the whole test process and comparison of AE signals of PVA fiber concretes with different fiber contents, the damage evolution process of PVA fiber concrete is analyzed. Finally, a qualitative evaluation of the damage degree is obtained using the kurtosis index and b-value of AE characteristic parameters. The results obtained using both methods are discussed. PMID:23012555

Li, Dongsheng; Cao, Hai

2012-01-01

399

Preparation and Characterization of Palm Leaf Incorporated Polyvinyl Alcohol Bio Composites  

NASA Astrophysics Data System (ADS)

The Bio Composites of palm leaf (PL) incorporated polyvinyl alcohol (PVA) has been prepared using solution cast technique. Structural and microhardness properties of pure PVA and PL filled PVA Bio Composites has been determined by using FTIR and Vicker's indentation techniquque respectively. The FTIR analysis reveals the presence of PL moieties in PVA, which indicates the good compatibility between PL and PVA. The values of microhardness increases in all composition of PL incorporated PVA films as compared to the pure PVA. This increment in the microhardness is attributed to the excellent binding of PL into PVA.

Patel, Arunendra Kumar; Bajpai, Rakesh; Keller, J. M.; Saha, Abhijit

2011-12-01

400

Synthesis of poly(vinyl ether)s with perfluoroalkyl pendant groups  

Microsoft Academic Search

2-Perfluoro(alkyl)ethyl vinyl ethers, F(CF2)nCH2CH2OCHCH2, (n = 6 or 8), were synthesized and polymerized by means of cationic initiators (HI\\/ZnI2 and CF3SO3H\\/(CH3)2S). The perfluorohexyl-substituted poly(vinyl ether) is completely amorphous. The polymer with perfluorooctyl segments shows side chain crystallization with a disordering transition. For the corresponding perfluorooctyl monomer a liquid-crystalline phase was observed before melting. Copolymerization experiments of the flurocarbon-segmented monomers with

Jens Höpken; Martin Möller; Myongsoo Lee; Virgil Percec

1992-01-01

401

Poly(vinyl chloride) ion-selective electrodes for Piribedil determination  

Microsoft Academic Search

Piribedil (PD) ion-selective electrodes have been constructed from poly(vinyl chloride) matrix membrane containing piribedil-tetraphenylborate (PD-TPB) as the electroactive component with dibutylphthalate or dioctylphthalate as the plasticizing solvent mediator. The electrodes displayed a linear response over the concentration range 2.0×10?5 to 10?2 M PD. The working pH ranges of the electrodes were 3.5–6.4 and 3.0–6.0, and the isothermal coefficients of the

Y. M Issa; M. M Hassouna; F. M Abdel-Gawad; E. M Hussien

2000-01-01

402

Poly(vinyl alcohol-co-lactic acid)\\/Hydroxyapatite Composites: Synthesis and Characterization  

Microsoft Academic Search

There is a wide range of applications where calcium phosphate and hydroxyapatite (HA) are used as biomaterials, e.g. as synthetic\\u000a bone grafts, coating on metal prostheses (like hip endoprostheses or dental implants) and drug carriers. In the study, the\\u000a design and synthesis of composites based on poly(vinyl alcohol-co-lactic acid)\\/hydroxyapatite (PVA-co-LA\\/HA) with potential\\u000a for biomedical applications, they are presented. The hydroxyapatite

Nita TudorachiAurica; Aurica P. Chiriac

2011-01-01

403

Cross-linked polyvinyl alcohols and oil reservoir permeability control therewith  

SciTech Connect

This patent describes an improved method of recovering oil under steam flooding conditions from an oil-bearing subterranean formation penetrated by an injection well and a production well, in which an aqueous fluid is injected into the formation through the injection well to displace oil to the production well. The improvement comprising employing, in at least a portion of the aqueous fluid injected into the formation, a cross-linked polymer obtained by cross-linking polyvinyl alcohol with a cross-linking agent which is a mixture of a phenolic component and an aldehyde or a mixture of a naphtholic component and an aldehyde.

Hoskin, D.H.; Shu, P.

1990-01-30

404

Electrospun nano-fibre mats with antibacterial properties from quaternised chitosan and poly(vinyl alcohol).  

PubMed

Nano-fibres containing quaternised chitosan (QCh) have been successfully prepared by electrospinning of QCh solutions mixed with poly(vinyl alcohol) (PVA). The average fibre diameter is in the range of 60-200 nm. UV irradiation of the composite electrospun nano-fibrous mats containing triethylene glycol diacrylate as cross-linking agent has resulted in stabilising of the nano-fibres against disintegration in water or water vapours. Microbiological screening has demonstrated the antibacterial activity of the photo-cross-linked electrospun mats against Staphylococcus aureus and Escherichia coli. The obtained nano-fibrous electrospun mats are promising for wound-healing applications. PMID:16750180

Ignatova, Milena; Starbova, Kirilka; Markova, Nadya; Manolova, Nevena; Rashkov, Iliya

2006-09-01

405

21 CFR 524.1484f - Neomycin sulfate, prednisolone acetate, tetracaine hydrochloride eardrops.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Neomycin sulfate, prednisolone acetate, tetracaine hydrochloride... § 524.1484f Neomycin sulfate, prednisolone acetate, tetracaine hydrochloride...neomycin base, 2.5 milligrams of prednisolone acetate, and 5 milligrams of...

2010-04-01

406

21 CFR 524.1881b - Prednisolone acetate-neomycin sulfate sterile suspension.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Prednisolone acetate-neomycin sulfate sterile...ANIMAL DRUGS § 524.1881b Prednisolone acetate-neomycin sulfate sterile... (a) Specifications. Prednisolone acetate-neomycin...

2010-04-01

407

Alignment of micro-crystals of Mn12-acetate and direct observation of single molecules thereof  

E-print Network

This dissertation focuses on three separate studies. First, magnetization of the Mn12- acetate was studied by low temperature hysteresis loops and DC magnetization data on magnetically aligned Mn12-acetate micro-crystals. Secondly, Mn12-acetate thin...

Seo, Dongmin

2009-05-15

408

Crystal structure of a mixed solvated form of amoxapine acetate  

PubMed Central

The mixed solvated salt 4-(2-chloro­dibenzo[b,f][1,4]oxazepin-11-yl)piperazin-1-ium acetate–acetic acid–cyclo­hexane (2/2/1), C17H17ClN3O+·C2H3O2 ?·C2H4O2·0.5C6H12, crystallizes with one mol­ecule of protonated amoxapine (AXPN), an acetate anion and a mol­ecule of acetic acid together with half a mol­ecule of cyclo­hexane. In the centrosymmetric crystal, both enanti­omers of the protonated AXPN mol­ecule stack alternatively along [001]. Acetate anions connect the AXPN cations through N—H?O hydrogen bonding in the [010] direction, creating a sheet lying parallel to (100). The acetic acid mol­ecules are linked to the acetate anions via O—H?O hydrogen bonds within the sheets. Within the sheets there are also a number of C—H?O hydrogen bonds present. The cyclo­hexane solvent mol­ecules occupy the space between the sheets.

Bhardwaj, Rajni M.; Raval, Vishal; Oswald, Iain D. H.; Florence, Alastair J.

2015-01-01

409

Increased brain uptake and oxidation of acetate in heavy drinkers  

PubMed Central

When a person consumes ethanol, the body quickly begins to convert it to acetic acid, which circulates in the blood and can serve as a source of energy for the brain and other organs. This study used 13C magnetic resonance spectroscopy to test whether chronic heavy drinking is associated with greater brain uptake and oxidation of acetic acid, providing a potential metabolic reward or adenosinergic effect as a consequence of drinking. Seven heavy drinkers, who regularly consumed at least 8 drinks per week and at least 4 drinks per day at least once per week, and 7 light drinkers, who consumed fewer than 2 drinks per week were recruited. The subjects were administered [2-13C]acetate for 2 hours and scanned throughout that time with magnetic resonance spectroscopy of the brain to observe natural 13C abundance of N-acetylaspartate (NAA) and the appearance of 13C-labeled glutamate, glutamine, and acetate. Heavy drinkers had approximately 2-fold more brain acetate relative to blood and twice as much labeled glutamate and glutamine. The results show that acetate transport and oxidation are faster in heavy drinkers compared with that in light drinkers. Our finding suggests that a new therapeutic approach to supply acetate during alcohol detoxification may be beneficial. PMID:23478412

Jiang, Lihong; Gulanski, Barbara Irene; De Feyter, Henk M.; Weinzimer, Stuart A.; Pittman, Brian; Guidone, Elizabeth; Koretski, Julia; Harman, Susan; Petrakis, Ismene L.; Krystal, John H.; Mason, Graeme F.

2013-01-01

410

The Effects of Acetate Buffer Concentration on Lysozyme Solubility  

NASA Technical Reports Server (NTRS)

The micro-solubility column technique was employed to systematically investigate the effects of buffer concentration on tetragonal lysozyme solubility. While keeping the NaCl concentrations constant at 2%, 3%, 4%, 5% and 7%, and the pH at 4.0, we have studied the solubility of tetragonal lysozyme over an acetate buffer concentration range of 0.01M to 0.5M as a function of temperature. The lysozyme solubility decreased with increasing acetate concentration from 0.01M to 0.1M. This decrease may simply be due to the net increase in solvent ionic strength. Increasing the acetate concentration beyond 0.1M resulted in an increase in the lysozyme solubility, which reached a peak at - 0.3M acetate concentration. This increase was believed to be due to the increased binding of acetate to the anionic binding sites of lysozyme, preventing their occupation by chloride. In keeping with the previously observed reversal of the Hoffmeister series for effectiveness of anions in crystallizing lysozyme, acetate would be a less effective precipitant than chloride. Further increasing the acetate concentration beyond 0.3M resulted in a subsequent gradual decrease in the lysozyme solubility at all NaCl concentrations.

Forsythe, Elizabeth L.; Pusey, Marc L.

1996-01-01

411

SAGA Complex Components and Acetate Repression in Aspergillus nidulans  

PubMed Central

Alongside the well-established carbon catabolite repression by glucose and other sugars, acetate causes repression in Aspergillus nidulans. Mutations in creA, encoding the transcriptional repressor involved in glucose repression, also affect acetate repression, but mutations in creB or creC, encoding components of a deubiquitination system, do not. To understand the effects of acetate, we used a mutational screen that was similar to screens that uncovered mutations in creA, creB, and creC, except that glucose was replaced by acetate to identify mutations that were affected for repression by acetate but not by glucose. We uncovered mutations in acdX, homologous to the yeast SAGA component gene SPT8, which in growth tests showed derepression for acetate repression but not for glucose repression. We also made mutations in sptC, homologous to the yeast SAGA component gene SPT3, which showed a similar phenotype. We found that acetate repression is complex, and analysis of facA mutations (lacking acetyl CoA synthetase) indicates that acetate metabolism is required for repression of some systems (proline metabolism) but not for others (acetamide metabolism). Although plate tests indicated that acdX- and sptC-null mutations led to derepressed alcohol dehydrogenase activity, reverse-transcription quantitative real-time polymerase chain reaction showed no derepression of alcA or aldA but rather elevated induced levels. Our results indicate that acetate repression is due to repression via CreA together with metabolic changes rather than due to an independent regulatory control mechanism. PMID:23173087

Georgakopoulos, Paraskevi; Lockington, Robin A.; Kelly, Joan M.

2012-01-01

412

Clostridiumm ljungdahlii, an anaerobic ethanol and acetate producing microorganism  

DOEpatents

A newly discovered microorganism was isolated in a biologically pure culture and designated Clostridium ljungdahlii, having the identifying characteristics of ATCC No. 49587. Cultured in an aqueous nutrient medium under anaerobic conditions, this microorganism is capable of producing ethanol and acetate from CO and H.sub.2 O and/or CO.sub.2 and H.sub.2 in synthesis gas. Under optimal growth conditions, the microorganism produces acetate in preference to ethanol. Conversely, under non-growth conditions, ethanol production is favored over acetate.

Gaddy, James L. (Fayetteville, AR); Clausen, Edgar C. (Fayetteville, AR)

1992-01-01

413

Clostridiumm ljungdahlii, an anaerobic ethanol and acetate producing microorganism  

DOEpatents

A newly discovered microorganism was isolated in a biologically pure culture and designated Clostridium ljungdahlii, having the identifying characteristics of ATCC No. 49587. Cultured in an aqueous nutrient medium under anaerobic conditions, this microorganism is capable of producing ethanol and acetate from CO and H[sub 2]O and/or CO[sub 2] and H[sub 2] in synthesis gas. Under optimal growth conditions, the microorganism produces acetate in preference to ethanol. Conversely, under non-growth conditions, ethanol production is favored over acetate. 3 figs.

Gaddy, J.L.; Clausen, E.C.

1992-12-22

414

Selective Cross-Coupling of Organic Halides with Allylic Acetates  

PubMed Central

A general protocol for the coupling of haloarenes with a variety of allylic acetates is presented. Strengths of the method are a tolerance for electrophilic (ketone, aldehyde) and acidic (sulfonamide, trifluoroacetamide) substrates and the ability to couple with a variety of substituted allylic acetates. Secondary alkyl bromides can also be allylated under slightly modified conditions, demonstrating the generality of the approach. Finally, the coupling of a reactive vinyl halide could be achieved by the use of a very hindered ligand and more reactive, branched allylic acetates. PMID:23095043

Anka-Lufford, Lukiana L.; Prinsell, Michael R.

2012-01-01

415

Gold-loaded carbon nanoparticles from poly(vinyl alcohol)-b-poly(acrylonitrile) non-shell-cross-linked micelles.  

PubMed

Herein we show that a new amphiphilic poly(vinyl alcohol)-b-poly(acrylonitrile) block copolymer dispersed in water can be easily loaded with gold nanoparticles by addition of chlorauric acid followed by reduction by sodium borohydride. After deposition of the so-loaded micelles onto a silicon wafer, followed by an appropriate thermal treatment, the poly(acrylonitrile) core of the micelles is carbonized, while the poly(vinyl alcohol) shell is completely decomposed and volatilized, leading to gold encapsulated in carbon nanoparticles. The morphology of the micelles is maintained during thermal treatment without requiring shell-cross-linking of the micelles prior to pyrolysis. PMID:19557781

Bryaskova, Rayna; Willet, Nicolas; Duwez, Anne-Sophie; Debuigne, Antoine; Lepot, Laurent; Gilbert, Bernard; Jérôme, Christine; Jérôme, Robert; Detrembleur, Christophe

2009-08-01

416

Water dispersible microbicidal cellulose acetate phthalate film  

PubMed Central

Background Cellulose acetate phthalate (CAP) has been used for several decades in the pharmaceutical industry for enteric film coating of oral tablets and capsules. Micronized CAP, available commercially as "Aquateric" and containing additional ingredients required for micronization, used for tablet coating from water dispersions, was shown to adsorb and inactivate the human immunodeficiency virus (HIV-1), herpesviruses (HSV) and other sexually transmitted disease (STD) pathogens. Earlier studies indicate that a gel formulation of micronized CAP has a potential as a topical microbicide for prevention of STDs including the acquired immunodeficiency syndrome (AIDS). The objective of endeavors described here was to develop a water dispersible CAP film amenable to inexpensive industrial mass production. Methods CAP and hydroxypropyl cellulose (HPC) were dissolved in different organic solvent mixtures, poured into dishes, and the solvents evaporated. Graded quantities of a resulting selected film were mixed for 5 min at 37°C with HIV-1, HSV and other STD pathogens, respectively. Residual infectivity of the treated viruses and bacteria was determined. Results The prerequisites for producing CAP films which are soft, flexible and dispersible in water, resulting in smooth gels, are combining CAP with HPC (other cellulose derivatives are unsuitable), and casting from organic solvent mixtures containing ?50 to ?65% ethanol (EtOH). The films are ?100 µ thick and have a textured surface with alternating protrusions and depressions revealed by scanning electron microscopy. The films, before complete conversion into a gel, rapidly inactivated HIV-1 and HSV and reduced the infectivity of non-viral STD pathogens >1,000-fold. Conclusions Soft pliable CAP-HPC composite films can be generated by casting from organic solvent mixtures containing EtOH. The films rapidly reduce the infectivity of several STD pathogens, including HIV-1. They are converted into gels and thus do not have to be removed following application and use. In addition to their potential as topical microbicides, the films have promise for mucosal delivery of pharmaceuticals other than CAP. PMID:14617380

Neurath, A Robert; Strick, Nathan; Li, Yun-Yao

2003-01-01

417

Inhibition of Ice Growth and Recrystallization by Zirconium Acetate and Zirconium Acetate Hydroxide  

PubMed Central

The control over ice crystal growth, melting, and shaping is important in a variety of fields, including cell and food preservation and ice templating for the production of composite materials. Control over ice growth remains a challenge in industry, and the demand for new cryoprotectants is high. Naturally occurring cryoprotectants, such as antifreeze proteins (AFPs), present one solution for modulating ice crystal growth; however, the production of AFPs is expensive and inefficient. These obstacles can be overcome by identifying synthetic substitutes with similar AFP properties. Zirconium acetate (ZRA) was recently found to induce the formation of hexagonal cavities in materials prepared by ice templating. Here, we continue this line of study and examine the effects of ZRA and a related compound, zirconium acetate hydroxide (ZRAH), on ice growth, shaping, and recrystallization. We found that the growth rate of ice crystals was significantly reduced in the presence of ZRA and ZRAH, and that solutions containing these compounds display a small degree of thermal hysteresis, depending on the solution pH. The compounds were found to inhibit recrystallization in a manner similar to that observed in the presence of AFPs. The favorable properties of ZRA and ZRAH suggest tremendous potential utility in industrial applications. PMID:23555701

Mizrahy, Ortal; Bar-Dolev, Maya; Guy, Shlomit; Braslavsky, Ido

2013-01-01

418

Fragrance material review on 2-(p-tolyloxy)ethyl acetate.  

PubMed

A toxicologic and dermatologic review of 2-(p-tolyloxy)ethyl acetate when used as a fragrance ingredient is presented. 2-(p-tolyloxy)ethyl acetate is a member of the fragrance structural group aryl alkyl alcohol simple acid esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 2-(p-tolyloxy)ethyl acetate were evaluated, then summarized, and includes physical properties data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414652

McGinty, D; Letizia, C S; Api, A M

2012-09-01

419

SOLVENT EXTRACTION OF WASTEWATERS FROM ACETIC-ACID MANUFACTURE  

EPA Science Inventory

Solvent extraction was evaluated as a potential treatment method for wastewaters generated during the manufacture of acetic acid. Possible goals for an extraction process were considered. For the wastewater samples studied, extraction appeared to be too expensive to be practical ...

420

Original article Effect of indole-3-acetic acid (plant auxin)  

E-print Network

Original article Effect of indole-3-acetic acid (plant auxin) on the preservation at 15 °C of boar; Effet de l'auxine végétale, l'acide 3-indole-acétique, sur la conservation du sperme de verrat pourl

Paris-Sud XI, Université de

421

Electronic interactions between gold films and mn12-acetate  

E-print Network

Interactions between Mn12–acetate molecular magnets and thin gold films have been explored in light of the theory of weak localization. Low-temperature measurements of the magnetoresistance of gold films of varying thicknesses, with and without...

Means, Joel Lewis

2009-05-15

422

Degradation by acetic acid for crystalline Si photovoltaic modules  

NASA Astrophysics Data System (ADS)

The degradation of crystalline Si photovoltaic modules during damp-heat test was studied using some test modules with and without polymer film insertion by observing electrical and electroluminescence properties and by chemical analyses. Acetic acid generated by the hydrolysis decomposition of ethylene vinyl acetate used as an encapsulant is the main origin of degradation. The change in electroluminescence images is explained on the basis of the corrosion of electrodes by acetic acid. On the other hand, little change was observed at the pn junction even after damp-heat test for a long time. Therefore, carrier generation occurs even after degradation; however, such generated carriers cannot be collected owing to corrosion of electrodes. The guiding principle that module structure and module materials without saving acetic acid into the modules was obtained.

Masuda, Atsushi; Uchiyama, Naomi; Hara, Yukiko

2015-04-01

423

A PROGESTOGEN (CHLORMADINONE ACETATE = CAP) FOR CYCLE CONTROL AND INFERTILITY  

E-print Network

A PROGESTOGEN (CHLORMADINONE ACETATE = CAP) FOR CYCLE CONTROL AND INFERTILITY TREATMENT IN THE MARE, CAP has been used for infertility treatments and cycle control in mares in Austria. In all indications

Paris-Sud XI, Université de

424

Microorganisms having enhanced resistance to acetate and methods of use  

DOEpatents

The present invention provides isolated or genetically modified strains of microorganisms that display enhanced resistance to acetate as a result of increased expression of a sodium proton antiporter. The present invention also provides methods for producing such microbial strains, as well as related promoter sequences and expression vectors. Further, the present invention provides methods of producing alcohol from biomass materials by using microorganisms with enhanced resistance to acetate.

Brown, Steven D; Yang, Shihui

2014-10-21

425

Intrinsic hydration of monopositive uranyl hydroxide, nitrate, and acetate cations  

Microsoft Academic Search

The intrinsic hydration of three monopositive uranyl-anion complexes (UO2A)+ (where A = acetate, nitrate, or hydroxide) was investigated using ion-trap mass spectrometry (IT-MS). The relative rates\\u000a for the formation of the monohydrates [(UO2A)(H2O)]+, with respect to the anion, followed the trend: Acetate ? nitrate ? hydroxide. This finding was rationalized in terms of\\u000a the donation of electron density by the

Winnie Chien; Victor Anbalagan; Melvin Zandler; Michael Van Stipdonk; Dorothy Hanna; Garold Gresham; Gary Groenewold

2004-01-01

426

Sample water removal method in volatile organic compound analysis based on diffusion through poly(vinyl fluoride) film  

Microsoft Academic Search

The humidity caught during air sampling or sample storage causes various problems during volatile organic compound (VOC) analysis and gives unreliable results. In this study, water vapour diffusion capacities through poly(vinyl fluoride) Tedlar, fluoroethylene propylene Teflon and Flex foil film were compared. A new approach to humidity removal has been tested for moderately polluted atmospheres. This approach consists in using

Sandra Beghi; Jean-Michel Guillot

2006-01-01

427

Influence of glass mechanical strengthening on the adhesion properties of poly(vinyl butyral) films to a float glass surface  

Microsoft Academic Search

The effects of various methods of mechanical strengthening of glass on the adhesion properties of poly(vinyl butyral) (PVB) film to a float glass surface were investigated. The mechanisms of the influence of the strengthening processes on the adhesion properties were analyzed. The influence of different types of pretreatment of the glass surface on the adhesion of the polymer films was

Alexander V. Gorokhovsky; Konstantin N. Matazov

2000-01-01

428

Synthesis using electrospinning and stabilization of single layer macroporous films and fibrous networks of poly(vinyl alcohol)  

Microsoft Academic Search

We demonstrated in this paper an electrospinning technique could be employed to prepare the single layer macroporous films and fibrous networks of poly(vinyl alcohol) (PVA). A crucial element using electrospinning on the development of these electrospun structures was to shorten the distance of from the needle tip to the collector (L), which resulted in the bond of the wet fibers

Youliang Hong; Tiecun Shang; Yanyan Li; Lizhu Wang; Ce Wang; Xuesi Chen; Xiabin Jing

2006-01-01

429

Calculation of the rate constant for the ultrasonic degradation of aqueous solutions of polyvinyl alcohol by viscometry  

Microsoft Academic Search

Ultrasonic degradation of polyvinyl alcohol (PVA) was carried out in aqueous solution at 25 °C. In this experiment, the effect of solution concentration on the rate of degradation was investigated. Kinetics of degradation was studied by viscometry method. The calculated rate constants indicate that degradation rate of PVA solutions decreases with increasing of solution concentration (C=glit?1). The calculated rate constants

Mohammad Taghi Taghizadeh; Abbas Mehrdad

2003-01-01

430

Polyvinyl alcohol–sulphanilic acid water soluble composite as corrosion inhibitor for mild steel in hydrochloric acid medium  

Microsoft Academic Search

The inhibitive action of synthesised polyvinyl alcohol–sulphanilic acid (PVASA) composite on the corrosion of commercial mild steel in 1M HCl medium has been investigated by weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopic (EIS) methods. Characterization of PVASA composite has been carried out using Fourier transform infrared spectroscopy (FTIR). Experimental results reveal that PVASA composite acts as an inhibitor in

M. Srimathi; R. Rajalakshmi; S. Subhashini

431

Prevention of Plasticizer Leaching From the Inner Surface of Narrow Polyvinyl Chloride Tube by DC Glow Discharge Plasma  

Microsoft Academic Search

The prevention of plasticizer leaching from the inner surface of a narrow polyvinyl chloride (PVC) tube by dc glow discharge plasma generated inside the tube was investigated. The inner surface of PVC tubes with a 4-mm inner diameter was treated by Ar plasma. The amount of plasticizer leached from the inner surface of the PVC tubes was measured by using

Xiao Qiong Wen; Xue Hua Liu; Gui Shi Liu

2010-01-01

432

Mechanical Properties of Benzoylated Oil Palm Empty Fruit Bunch Short Fiber Reinforced Poly(vinyl chloride) Composites  

Microsoft Academic Search

The influence of untreated and benzoylated oil palm empty fruit bunch (OPEFB) short fiber loading on the mechanical properties of the poly(vinyl chloride) (PVC) composite was studied. Benzoylated OPEFB was produced by mixing OPEFB with NaOH solution and agitating vigorously with benzoyl chloride. The PVC resin, various additives, and OPEFB were first dry blended using a laboratory mixer before being

Aznizam Abu Bakar; Norfhairna Baharulrazi

2008-01-01

433

Study on Immobilization Activated Sludge by Polyvinyl Alcohol-sodium Alginate - Calcium Nitrate in Domestic Sewage Treatment  

Microsoft Academic Search

Preparation conditions of immobilization activated sludge were studied with polyvinyl alcohol-sodium alginate as carrier and calcium nitrate as cross linking agent. Physical properties and removal effect of immobilization activated sludge were also investigated, where cross linking agent was boric acid, calcium chloride, calcium nitrate, respectively. The effect of sewage treatment was compared with activated sludge cross optimum linker calcium nitrate

Nie Qian; Jian Peichao; Liu Zhibin; Gu Fang

2010-01-01

434

Preparation of biomembrane by immobilizing enriched ammonia-oxidizing bacteria (AOB) in polyvinyl alcohol (PVA) for biosensor  

Microsoft Academic Search

A biomembrane that was used to make a biosensor for detecting inhibitor of ammoia oxidation was prepared by entrapping enriched ammonia-oxidizing bacteria (AOB) in polyvinyl alcohol (PVA). AOB were enriched by fed batch cultivation with using return activated sludge from A 2 \\/O process as seed. Enrichment of AOB was confirmed by denaturing gradient gel electrophoresis (DGGE) analysis. The optimum

Rong Cui; Jinling Li; Ke Zhang; Jinglong Han

2011-01-01

435

Interactions of linear and cross-linked polyacrylic acid with polyvinyl ether of ethyleneglycol in some aliphatic alcohols  

Microsoft Academic Search

Summary  \\u000a The interaction of linear and cross-linked polyacrylic acid (PAA) with polyvinyl ether of ethyleneglycol (PVEEG) has been\\u000a studied in ethanol, isopropanol and their mixture. Formation of interpolymer complexes (IPC) in solutions is accompanied by\\u000a aggregation of compact particles. Gels of PAA undergo shrinking in solutions of PVEEG.

Zauresh S. Nurkeeva; Grigoriy A. Mun; Vitaliy V. Khutoryanskiy; Victor A. Kan; Alexei A. Zotov; Erengaip M. Shaikhutdinov

2000-01-01

436

VALIDATION OF AN EPA METHOD FOR THE ION CHROMATOGRAPHIC DETERMINATION OF PERCHLORATE IN FERTILIZERS USING A POLYVINYL ALCOHOL GEL RESIN.  

EPA Science Inventory

This paper summarizes the key points of a joint study between the EPA and Metrohm-Peak, Inc., on the use of polyvinyl alcohol [PVA] columns for the ion chromatographic determination of percholorate in aqueous leachates or solutions of fertilizers. A series of fertilizer samples ...

437

Water transport in cement-in-polymer dispersions at variable temperature studied by magnetic resonance imaging  

SciTech Connect

The hydration of recently developed cement-in-polymer dispersions (c/p) containing 30% and 40% poly (vinyl acetate) [PVAc] and 30% poly(vinyl alcohol) [PVA] was monitored on-line at various temperatures using {sup 1}H Single Point Imaging (SPI). The physical changes undergone by the materials as well as the complex manner in which the absorption process takes place and the evolution of the spin density were characterized and were found to be strongly dependent on the nature and amount of polymer and on the temperature. Based on the results obtained we propose a simple mathematical model which can be used to characterize the behaviour of the c/p dispersions exposed to hydration at variable temperature.

Olaru, A.M., E-mail: aolaru@mc.rwth-aachen.de; Bluemich, B.; Adams, A., E-mail: aadams@mc.rwth-aachen.de

2013-02-15

438

N-Type Thermoelectric Performance of Functionalized Carbon Nanotube-Filled Polymer Composites  

PubMed Central

Carbon nanotubes (CNTs) were functionalized with polyethyleneimine (PEI) and made into composites with polyvinyl acetate (PVAc). CNTs were dispersed with different amounts of sodium dodecylbenzenesulfonate (SDBS) prior to the PEI functionalization. The resulting samples exhibit air-stable n-type characteristics with electrical conductivities as great as 1500 S/m and thermopowers as large as ?100 µV/K. Electrical conductivity and thermopower were strongly affected by CNT dispersion, improving the properties with better dispersion with high concentrations of SDBS. This improvement is believed to be due to the increase in the number of tubes that are evenly coated with PEI in a better-dispersed sample. Increasing the amount of PEI relative to the other constituents positively affects thermopower but not conductivity. Air exposure reduces both thermopower and conductivity presumably due to oxygen doping (which makes CNTs p-type), but stable values were reached within seven days following sample fabrication. PMID:23133605

Freeman, Dallas D.; Choi, Kyungwho; Yu, Choongho

2012-01-01

439

PREPARATION OF WATER-SOLUBLE AND WATER-SWELLABLE STARCH ACETATES USING MICROWAVE HEATING  

Technology Transfer Automated Retrieval System (TEKTRAN)

Starch acetates of degree of substitution 0.1-1.5 were prepared by heating corn starch, acetic acid and acetic anhydride in sealed, stirred, Teflon vessels in a microwave reactor. Reaction efficiencies were typically >90% at reaction temperatures of 150-160 deg C for 4-7 minutes. Starch acetates w...

440

Ulipristal acetate: a review of its use in emergency contraception.  

PubMed

Ulipristal acetate (ellaOne®; ella®) is the first of a new class of selective progesterone receptor modulators, and is indicated for emergency contraception within 120 hours after unprotected sexual intercourse or contraceptive failure. The principal effect of ulipristal acetate is to inhibit or delay ovulation. This effect may result from the drug's ability to delay the onset of luteinizing hormone (LH) surge or postpone LH peak if LH surge has started, or possibly by a direct inhibitory effect on follicular rupture, when administered in the follicular phase (including just before ovulation). In clinical trials, a single oral dose of ulipristal acetate 30?mg was effective in preventing pregnancies in women requesting emergency contraception after unprotected sexual intercourse and provided sustained efficacy throughout the 120-hour postcoital period in which it is indicated. When compared with levonorgestrel in well designed noninferiority trials, it was no less effective in preventing pregnancies when administered within 72 hours of unprotected intercourse, but was more effective when administered later (within 72-120 hours). Results of a meta-analysis suggest that ulipristal acetate may be more effective than levonorgestrel from day 1 and throughout the entire 5-day period following unprotected sexual intercourse. Ulipristal acetate is generally well tolerated, with a similar tolerability profile to that of levonorgestrel. In general, the onset of menses is delayed by 2-3 days following treatment. Although, ulipristal acetate is more expensive than levonorgestrel, it may represent a cost-effective alternative to levonorgestrel for women requesting emergency contraception within 120 hours of unprotected intercourse. Thus, ulipristal acetate provides effective, sustained and well tolerated emergency contraception when taken within 120 hours of unprotected sexual intercourse, thereby offering an extended treatment window compared with levonorgestrel, which should be administered within 72 hours. PMID:21568368

McKeage, Kate; Croxtall, Jamie D

2011-05-01

441

Tetrazole acetic acid: Tautomers, conformers, and isomerization  

NASA Astrophysics Data System (ADS)

Monomers of (tetrazol-5-yl)-acetic acid (TAA) were obtained by sublimation of the crystalline compound and the resulting vapors were isolated in cryogenic nitrogen matrices at 13 K. The conformational and tautomeric composition of TAA in the matrix was characterized by infrared spectroscopy and vibrational calculations carried out at the B3LYP/6-311++G(d,p) level. TAA may adopt two tautomeric modifications, 1H- and 2H-, depending on the position of the annular hydrogen atom. Two-dimensional potential energy surfaces (PESs) of TAA were theoretically calculated at the MP2/6-311++G(d,p) level, for each tautomer. Four and six symmetry-unique minima were located on these PESs, for 1H- and 2H-TAA, respectively. The energetics of the detected minima was subsequently refined by calculations at the QCISD level. Two 1H- and three 2H-conformers fall within the 0-8 kJ mol-1 energy range and should be appreciably populated at the sublimation temperature (˜330 K). Observation of only one conformer for each tautomer (1ccc and 2pcc) is explained in terms of calculated barriers to conformational rearrangements. All conformers with the cis O=COH moiety are separated by low barriers (less than 10 kJ mol-1) and collapse to the most stable 1ccc (1H-) and 2pcc (2H-) forms during deposition of the matrix. On the trans O=COH surfaces, the relative energies are very high (between 12 and 27 kJ mol-1). The trans forms are not thermally populated at the sublimation conditions and were not detected in matrices. One high-energy form in each tautomer, 1cct (1H-) and 2pct (2H-), was found to differ from the most stable form only by rotation of the OH group and separated from other forms by high barriers. This opened a perspective for their stabilization in a matrix. 1cct and 2pct were generated in the matrices selectively by means of narrow-band near-infrared (NIR) irradiations of the samples at 6920 and 6937 cm-1, where the first OH stretching overtone vibrations of 1ccc and 2pcc occur. The reverse transformations could be induced by irradiations at 7010 and 7030 cm-1, transforming 1cct and 2pct back to 1ccc and 2pcc, also selectively. Besides the NIR-induced transformations, the photogenerated 1cct and 2pct forms also decay in N2 matrices back to 1ccc and 2pcc spontaneously, with characteristic decay times of hours (1H) and tens of minutes (2H). The decay mechanism is rationalized in terms of the proton tunneling. In crystals, TAA exists exclusively as 1H-tautomer. By contrast, the tautomeric composition of the matrix-isolated monomers was found to consist of both 1H- and 2H-tautomers, in comparable amounts. A mechanistic discussion of the tautomerization process occurring during sublimation, accounting also for the observed minor decomposition of TAA leading to CO2 and 5-methyl-tetrazole, is proposed.

Araujo-Andrade, C.; Reva, I.; Fausto, R.

2014-02-01

442

Zuclopenthixol acetate for acute schizophrenia and similar serious mental illnesses  

PubMed Central

Background Medication used for acute aggression in psychiatry must have rapid onset of effect, low frequency of administration and low levels of adverse effects. Zuclopenthixol acetate is said to have these properties. Objectives To estimate the clinical effects of zuclopenthixol acetate for the management of acute aggression or violence thought to be due to serious mental illnesses, in comparison to other drugs used to treat similar conditions. Search methods We searched the Cochrane Schizophrenia’s Group Trials Register (July 2011). We supplemented this by citation searching and personal contact with authors and relevant pharmaceutical companies. Selection criteria All randomised clinical trials involving people thought to have serious mental illnesses comparing zuclopenthixol acetate with other drugs. Data collection and analysis Two review authors extracted and cross-checked data independently. We calculated fixed-effect relative risks (RR) and 95% confidence intervals (CI) for dichotomous data. We analysed by intention-to-treat. We used mean differences (MD) for continuous variables. Main results We found no data for the primary outcome, tranquillisation. Compared with haloperidol, zuclopenthixol acetate was no more sedating at two hours (n = 40, 1 RCT, RR 0.60, 95% CI 0.27 to 1.34). People given zuclopenthixol acetate were not at reduced risk of being given supplementary antipsychotics (n = 134, 3 RCTs, RR 1.49, 95% CI 0.97 to 2.30) although additional use of benzodiazepines was less (n = 50, 1 RCT, RR 0.03, 95% CI 0.00 to 0.47). People given zuclopenthixol acetate had fewer injections over seven days compared with those allocated to haloperidol IM (n = 70, 1 RCT, RR 0.39, 95% CI 0.18 to 0.84, NNT 4, CI 3 to 14). We found no data on more episodes of aggression or harm to self or others. One trial (n = 148) reported no significant difference in adverse effects for people receiving zuclopenthixol acetate compared with those allocated haloperidol at one, three and six days (RR 0.74, 95% CI 0.43 to 1.27). Compared with haloperidol or clotiapine, people allocated zuclopenthixol did not seem to be at more risk of a range of movement disorders (< 20%). Three studies found no difference in the proportion of people getting blurred vision/dry mouth (n = 192, 2 RCTs, RR at 24 hours 0.90, 95% CI 0.48 to 1.70). Similarly, dizziness was equally infrequent for those allocated zuclopenthixol acetate compared with haloperidol (n = 192, 2 RCTs, RR at 24 hours 1.15, 95% CI 0.46 to 2.88). There was no difference between treatments for leaving the study before completion (n = 522, RR 0.85, 95% CI 0.31 to 2.31). One study reported no difference in adverse effects and outcome scores, when high dose (50-100 mg/injection) zuclopenthixol acetate was compared with low dose (25-50 mg/injection) zuclopenthixol acetate. Authors’ conclusions Recommendations on the use of zuclopenthixol acetate for the management of psychiatric emergencies in preference to ‘standard’ treatment have to be viewed with caution. Most of the small trials present important methodological flaws and findings are poorly reported. This review did not find any suggestion that zuclopenthixol acetate is more or less effective in controlling aggressive acute psychosis, or in preventing adverse effects than intramuscular haloperidol, and neither seemed to have a rapid onset of action. Use of zuclopenthixol acetate may result in less numerous coercive injections and low doses of the drug may be as effective as higher doses. Well-conducted pragmatic randomised controlled trials are needed. PMID:22513898

Jayakody, Kaushadh; Gibson, Roger Carl; Kumar, Ajit; Gunadasa, Shalmini

2014-01-01

443

Electrospun polyvinyl alcohol-collagen-hydroxyapatite nanofibers: a biomimetic extracellular matrix for osteoblastic cells  

NASA Astrophysics Data System (ADS)

The failure of prosthesis after total joint replacement is due to the lack of early implant osseointegration. In this study polyvinyl alcohol-collagen-hydroxyapatite (PVA-Col-HA) electrospun nanofibrous meshes were fabricated as a biomimetic bone-like extracellular matrix for the modification of orthopedic prosthetic surfaces. In order to reinforce the PVA nanofibers, HA nanorods and Type I collagen were incorporated into the nanofibers. We investigated the morphology, biodegradability, mechanical properties and biocompatibility of the prepared nanofibers. Our results showed these inorganic-organic blended nanofibers to be degradable in vitro. The encapsulated nano-HA and collagen interacted with the PVA content, reinforcing the hydrolytic resistance and mechanical properties of nanofibers that provided longer lasting stability. The encapsulated nano-HA and collagen also enhanced the adhesion and proliferation of murine bone cells (MC3T3) in vitro. We propose the PVA-Col-HA nanofibers might be promising modifying materials on implant surfaces for orthopedic applications.

Song, Wei; Markel, David C.; Wang, Sunxi; Shi, Tong; Mao, Guangzhao; Ren, Weiping

2012-03-01

444

Dielectric investigations and ac conductivity of polyvinyl alcohol films doped with europium and terbium chloride  

NASA Astrophysics Data System (ADS)

Differential scanning calorimetry (DSC) was used to identify the phase transitions of polyvinyl alcohol (PVA) doped with europium chloride (EuCl 3) and terbium chloride (TbCl 3). The dielectric constant and the loss tangent behavior of the investigated samples were studied as a function of temperature in the frequency range 1-100 kHz. The detailed analysis of the results showed that dielectric dispersion consists of both dipolar and interfacial polarization. The temperature coefficient of permittivity (TCP) and the electrical dipole moment ( ?) were calculated. Also, the activation energy for the glass relaxation process from the dielectric loss tangent measurements was calculated. Measurements of the ac conductivity as a function of frequency at different temperatures indicated that the correlated barrier hopping (CBH) model is the most suitable mechanism for the ac conduction behavior. The ac parameters, such as hopping distance ( R, Rmin), polaron binding energy ( UM) and Coulombic barrier height ( Uh) were calculated.

Abd El-kader, F. H.; Osman, W. H.; Mahmoud, K. H.; Basha, M. A. F.

2008-10-01

445

Improvement of polyvinyl alcohol properties by adding nanocrystalline cellulose isolated from banana pseudostems.  

PubMed

Cellulose nanocrystals (CNCs) isolated from banana pseudostems fibers (BPF) of the Pacovan variety were used as fillers in a polyvinyl alcohol (PVOH) matrix to yield a nanocomposite. The fibers from the external fractions of the BPF were alkaline bleached and hydrolyzed under acidic conditions (H2SO4 62% w/w, 70 min, 45 °C) to obtain CNCs with a length (L) of 135.0 ± 12.0 nm and a diameter (D) of 7.2 ± 1.9 nm to yield an aspect ratio (L/D) of 21.2. The CNCs were applied to PVOH films at different concentrations (0%, 1%, 3%, and 5% w/w, dry basis). With higher concentrations of CNCs, the water-vapor barrier of the films increased, while the optical properties changed very little. Increasing the concentration of the CNCs up to 3% significantly improved the mechanical properties of the nanocomposite. PMID:25129731

Pereira, André Luís S; do Nascimento, Diego M; Souza Filho, Men de Sá M; Morais, João Paulo S; Vasconcelos, Niedja F; Feitosa, Judith P A; Brígida, Ana Iraidy S; Rosa, Morsyleide de F

2014-11-01

446

Enhanced mechanical properties and morphological characterizations of poly(vinyl alcohol) carbon nanotube composite films  

NASA Astrophysics Data System (ADS)

Tensile tests were carried out on free-standing composite films of poly(vinyl alcohol) (PVA) and multiwall carbon nanotubes (MWNTs) for different loading levels. Results show that overall mechanical properties of the composite were greatly improved as compared to the neat PVA film. For PVA-based materials at significant high loading level such as 9.1 wt.% MWNTs, considerable increases in Young's modulus, tensile strength and toughness by factors of 4.5, 2.7 and 4.1, respectively, were achieved. Raman, SEM, TEM, and DSC techniques were used to evaluate the PVA/MWNTs composite system. Strong acid-modification of the pristine MWNTs and the subsequent ultrasonication processing allowed good distribution of the nanotubes in the matrix. SEM together with DSC result shows apparent good wetting of the nanotubes by the PVA matrix, which are supportive of good interfacial bonding between the modified carbon nanotubes and the hosting polymer matrix.

Chen, Wei; Tao, Xiaoming; Xue, Pu; Cheng, Xiaoyin

2005-12-01

447

Nitrogen-doped carbon dots derived from polyvinyl pyrrolidone and their multicolor cell imaging  

NASA Astrophysics Data System (ADS)

Nitrogen-doped carbon dots (N-CDs) with a high quantum yield of 19.6% were prepared by calcining polyvinyl pyrrolidone (PVP, K-30), and then modified with 4,7,10-trioxa-1,13-tridecanediamine. The as-prepared N-CDs exhibited excitation-dependent and pH-sensitive photoluminescence. Transmission electron microscopy and Raman spectra demonstrated the graphitic structure of the N-CDs. Fourier transform infrared spectroscopy and x-ray diffraction studies revealed successful passivation and the presence of hydrophilic groups on the surface. Importantly, such modified quantum dots acted as good multicolor cell imaging probes due to their excellent fluorescent properties, low cytotoxicity and fine dispersity.

Ding, Hui; Zhang, Peng; Wang, Tian-Yi; Kong, Ji-Lie; Xiong, Huan-Ming

2014-05-01

448

Chemical alteration of poly(vinyl fluoride) Tedlar by hyperthermal atomic oxygen  

NASA Astrophysics Data System (ADS)

In this study the erosion of poly(vinyl fluoride) Tedlar by hyperthermal atomic oxygen (AO) has been examined using X-ray photoelectron spectroscopy (XPS). Initially the Tedlar film had F/C and O/C atom ratios of 0.45 and 0.11, which decrease to 0.018 and 0.04, respectively, after a 2-h exposure to a flux of 2 × 10 15 atoms/cm 2 s AO with an average kinetic energy of 5 eV. This exposure essentially produced a graphitic or amorphous carbon-like layer with a carbon content greater than 90 at.%. Longer AO exposures do not alter the composition of this layer significantly. Exposure to O 2 or air nearly doubles the oxygen content in the near-surface region. This is due to dissociative oxygen adsorption at reactive sites formed at the polymer surface during AO exposure. Further exposure to AO removes this chemisorbed oxygen.

Hoflund, Gar B.; Everett, Michael L.

2005-01-01

449

Glass transition behavior of the vitrification solutions containing propanediol, dimethyl sulfoxide and polyvinyl alcohol.  

PubMed

Knowledge of the glass transition behavior of vitrification solutions is important for research and planning of the cryopreservation of biological materials by vitrification. This brief communication shows the analysis for the glass transition and glass stability of the multi-component vitrification solutions containing propanediol (PE), dimethyl sulfoxide (Me2SO) and polyvinyl alcohol (PVA) by using differential scanning calorimetry (DSC) during the cooling and subsequent warming between 25 and -150 degrees C. The glass formation of the solutions was enhanced by introduction of PVA. Partial glass formed during cooling and the fractions of free water in the partial glass matrix increased with the increasing of PVA concentration, which caused slight decline of glass transition temperature, T(g). Exothermic peaks of devitrification were delayed and broadened, which may result from the inhibition of ice nucleation or recrystallization of PVA. PMID:19026625

Wang, Hai-Yan; Lu, Shu-Shen; Lun, Zhao-Rong

2009-02-01

450

Polyvinyl pyridine metal complex as permanent antimicrobial finishing for viscose fabric.  

PubMed

Viscose fabrics were treated with polyvinyl pyridine (PVP) using padding technique, followed by oxidation with hydrogen peroxide or peracetic acid, which was prepared by the reaction of tetra acetyl ethylene diamine (TAED) with hydrogen peroxide. Peracetic acid gives higher oxidation of PVP than hydrogen peroxide. FTIR study proved the formation of N-oxide as a result of oxidation. Incorporation of copper and silver ion onto oxidized PVP was also proved by FTIR. The antimicrobial study emphasise that Cu/oxidized PVP and Ag/oxidized PVP have retarded the growth of bacteria significantly, and Ag/oxidized PVP has a far better biocidal activity. The antibacterial activity of both metal ions survived after washing 10 times. PMID:18835405

Kantouch, A; El-Sayed, A Atef

2008-12-01

451

Low temperature magnetoresistance and magnetization studies of iron encapsulated multiwall carbon nanotube/polyvinyl chloride composites  

NASA Astrophysics Data System (ADS)

We present the experimental results of temperature dependent magnetoresistance (MR) and the magnetization studies of iron encapsulated multiwall carbon nanotube (MWCNT)/polyvinyl chloride (PVC) composites with different wt% of MWCNTs. Transmission electron microscopy characterization shows that MWCNTs are encapsulated with rod-shaped iron nanoparticles of aspect ratio of ~3. The MR behavior of 1.9 wt% MWCNT/PVC sample shows dominance of forward scattering and wave function shrinkage whereas, weak localization and electron-electron interactions explain the MR data of higher wt% samples (9.1, 16.6 and 44.4 wt%). The composites of 4.7 and 9.1 wt% exhibit ferromagnetic behavior at all temperatures with room temperature coercivities of ~1036 and 628 Oe, respectively.

Vasanthkumar, M. S.; Sameera, I.; Bhatia, Ravi; Prasad, V.; Jayanna, H. S.

2015-01-01

452

Highly reflective and adhesive surface of aluminized polyvinyl chloride film by vacuum evaporation  

NASA Astrophysics Data System (ADS)

Aluminized poly(vinyl chloride) (PVC) film with high reflectivity and strong adhesion was facilely fabricated by vacuum evaporation. The technical study revealed that both alkali-pretreatment of the PVC matrix and thermal annealing after aluminization could greatly promote the peeling adhesion force of this metal/polymer composite by producing interfacial active chemical groups and removing the inner stress, respectively. Reflectivity test and AFM study indicated that the reflecting capacitance of the aluminum coating was closely related to the surface roughness, which can be easily controlled by modulating deposition of aluminum. Moreover, the formation of aluminum layer follows an island model process, and a continuous and smooth coating with highest reflectivity and lowest surface resistance was achieved at deposition time of 60 s. We anticipate that the cost-effective metallized PVC film by this strategy may find extensive applications in light harvesting, solar energy, and flexible mirrors, among others.

Li, Denian; Tai, Qile; Feng, Qiang; Li, Qi; Xu, Xizhe; Li, Hairong; Huang, Jing; Dong, Lijie; Xie, Haian; Xiong, Chuanxi

2014-08-01

453

Study of polyvinyl alcohol nanofibrous membrane by electrospinning as a magnetic nanoparticle delivery approach  

SciTech Connect

Electrospinning technique was used to fabricate polyvinyl alcohol (PVA)-based magnetic biodegradable nanofibers. PVA solution was mixed with ferrofluid or magnetic nanoparticles (MNPs) powder and formed two individual nanofibrous membranes (PVA/ferrofluid and PVA/MNPs powder) by electrospinning. The surface morphology of the nanofibrous membrane was characterized by scanning electron microscopy and the magnetic properties were measured by vibrating sample magnetometer. Macrophages (RAW 264.7) were co-cultured with the nanofibrous membranes for 12, 24, and 48 h and exhibited good cell viability (>95%). Results showed that the PVA fibers would be degraded and the embedded Fe{sub 3}O{sub 4} nanoparticles would be released and delivered to cells.

Ger, Tzong-Rong; Huang, Hao-Ting; Hu, Keng-Shiang [Institute of NanoEngineering and MicroSystems, National Tsing Hua University, Hsinchu, Taiwan (China); Huang, Chen-Yu [Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu, Taiwan (China); Lai, Jun-Yang [Department of Applied Physics, National Ping Tung University of Education, Pingtung, Taiwan (China); Chen, Jiann-Yeu [Center of Nanoscience and Nanotechnology, National Chung Hsing University, Taichung, Taiwan (China); Lai, Mei-Feng, E-mail: mflai@mx.nthu.edu.tw [Institute of NanoEngineering and MicroSystems, National Tsing Hua University, Hsinchu, Taiwan (China); Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu, Taiwan (China)

2014-05-07

454

Asymmetric supercapacitor based on nanostructured graphene foam/polyvinyl alcohol/formaldehyde and activated carbon electrodes  

NASA Astrophysics Data System (ADS)

We present the electrochemical results of highly porous and interconnected carbon material by activation of graphene foam/polyvinyl alcohol-formaldehyde composite material designated as GF/PVA-F. Asymmetric supercapacitor devices were fabricated using the activated material (GF/PVA-F) and activated carbon (AC) as the positive and negative electrodes respectively. The device exhibited a maximum energy density of 42 mWh cm-2, a power density of 0.5 W cm-2 and 98% retention of its initial capacitance after 2000 cycles in an extended cell potential window of 1.8 V in 1 M Na2SO4 aqueous electrolyte. This work shows the great potential of this material for high performance energy storage application.

Bello, Abdulhakeem; Barzegar, Farshad; Momodu, Damilola; Dangbegnon, Julien; Taghizadeh, Fatemeh; Fabiane, Mopeli; Manyala, Ncholu

2015-01-01

455

Electrospun polyvinyl-alcohol nanofibers as oral fast-dissolving delivery system of caffeine and riboflavin.  

PubMed

Fast-dissolving drug delivery systems were prepared by electrospinning using polyvinyl alcohol (PVA) as the filament-forming polymer and drug carrier. Caffeine and riboflavin were used as the model drugs. Scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) and X-ray diffraction were applied to investigate the physicochemical properties of electrospun nanofibers. The SEM images showed that nanofibers prepared from electrospinning PVA/drug aqueous solutions possessed an ultrafine morphology with an average diameter in the range of 260-370 nm. Pharmacotechnical tests showed that PVA/caffeine and PVA/riboflavin nanofibrous mats had almost the same dissolution time (about 1.5 s) and wetting time (about 4.5 s). The release measurements indicated that drugs can be released in a burst manner (caffeine to an extent of 100% and riboflavin to an extent of 40% within 60 s) from the PVA nanofibrous matrices. PMID:23201736

Li, Xiaoqiang; Kanjwal, Muzafar A; Lin, Lin; Chronakis, Ioannis S

2013-03-01

456

Electrospun polyvinyl alcohol/chitosan composite nanofibers involving Au nanoparticles and their in vitro release properties.  

PubMed

Au nanoparticles (Au NPs) containing polyvinyl alcohol (PVA)/chitosan (CS) composite nanofibers were successfully prepared by a simple and effective method called electrospinning. Au NPs were firstly synthesized under a mild condition with CS as the reducing agent and stabilizer, followed by being mixed with PVA solution and then the resulting fibers were fabricated. The research indicated that Au NPs were indeed doped into the as-prepared fibers and the composite fibers well preserved Au NPs' unique optical characteristics. Additionally, with the adjustment of the weight ratios between PVA and CS, the diameter distribution and the morphology of the nanofibers were largely changed. In vitro drug release experiments demonstrated that the drug release rate can be conveniently controlled by changing the crosslink time. PMID:25428096

Yan, Eryun; Fan, Shan; Li, Xunqi; Wang, Cheng; Sun, Zhiyao; Ni, Liang; Zhang, Deqing

2013-01-01

457

Fabrication of ?-chitin whisker-reinforced poly(vinyl alcohol) nanocomposite nanofibres by electrospinning  

NASA Astrophysics Data System (ADS)

The present contribution reports, for the first time, the successful fabrication of ?-chitin whisker-reinforced poly(vinyl alcohol) (PVA) nanocomposite nanofibres by electrospinning. The ?-chitin whiskers were prepared from ?-chitin flakes from shrimp shells by acid hydrolysis. The as-prepared chitin whiskers exhibited lengths in the range 231-969 nm and widths in the range 12-65 nm, with the average length and width being about 549 and 31 nm, respectively. Successful incorporation of the chitin whiskers within the as-spun PVA/chitin whisker nanocomposite nanofibres was verified by infrared spectroscopic and thermogravimetric methods. The incorporation of chitin whiskers within the as-spun nanocomposite fibre mats increased the Young's modulus by about 4-8 times over that of the neat as-spun PVA fibre mat.

Junkasem, Jirawut; Rujiravanit, Ratana; Supaphol, Pitt

2006-09-01

458

Microporous poly(vinyl methyl ether) hydrogels prepared by ?-ray irradiation at different heating rates  

NASA Astrophysics Data System (ADS)

We prepared thermoresponsive and microporous polymer hydrogels by ?-ray irradiation of aqueous solutions poly(vinyl methyl ether) (PVME) at different heating rates. Under all temperature programs, opaque and heterogeneous PVME gels formed, which swelled at temperatures below the lower critical solution temperature and shrank at temperatures above it. All of the samples contained porous and phase-separated structures. The shape and size of the gel pores varied depending on the temperature programs. Gels having a sponge-like continuous porous structure formed only when the radiation-induced crosslinking was carried out at an optimum heating rate, which we found to be 0.11-0.13°C min -1. For temperature changes between 10°C and 40°C, gels with this structure showed rapid volume transitions on a time scale of about a minute.

Kishi, Ryoichi; Kihara, Hideyuki; Miura, Toshiaki; Ichijo, Hisao

2005-04-01

459

Evaluation of electrospun polyvinyl chloride/polystyrene fibers as sorbent materials for oil spill cleanup.  

PubMed

A novel, high-capacity oil sorbent consisting of polyvinyl chloride (PVC)/polystyrene (PS) fiber was prepared by an electrospinning process. The sorption capacity, oil/water selectivity, and sorption mechanism of the PVC/PS sorbent were studied. The results showed that the sorption capacities of the PVC/PS sorbent for motor oil, peanut oil, diesel, and ethylene glycol were 146, 119, 38, and 81 g/g, respectively. It was about 5-9 times that of a commercial polypropylene (PP) sorbent. The PVC/PS sorbent also had excellent oil/water selectivity (about 1000 times) and high buoyancy in the cleanup of oil over water. The SEM analysis indicated that voids among fibers were the key for the high capacity. The electrospun PVC/PS sorbent is a better alternative to the widely used PP sorbent for oil spill cleanup. PMID:21513310

Zhu, Haitao; Qiu, Shanshan; Jiang, Wei; Wu, Daxiong; Zhang, Canying

2011-05-15

460

Antibacterial surfaces by adsorptive binding of polyvinyl-sulphonate-stabilized silver nanoparticles  

NASA Astrophysics Data System (ADS)

This paper presents a novel and facile method for the generation of efficient antibacterial coatings which can be applied to practically any type of substrate. Silver nanoparticles were stabilized with an adsorbed surface layer of polyvinyl sulphonate (PVS). This steric layer provided excellent colloidal stability, preventing aggregation over periods of months. PVS-coated silver nanoparticles were bound onto amine-containing surfaces, here produced by deposition of an allylamine plasma polymer thin film onto various substrates. SEM imaging showed no aggregation upon surface binding of the nanoparticles; they were well dispersed on amine surfaces. Such nanoparticle-coated surfaces were found to be effective in preventing attachment of Staphylococcus epidermidis bacteria and also in preventing biofilm formation. Combined with the ability of plasma polymerization to apply the thin polymeric binding layer onto a wide range of materials, this method appears promising for the fabrication of a wide range of infection-resistant biomedical devices.

Vasilev, Krasimir; Sah, Vasu R.; Goreham, Renee V.; Ndi, Chi; Short, Robert D.; Griesser, Hans J.

2010-05-01

461

Hydroxyapatite nanoparticles: electrospinning and calcination of hydroxyapatite/polyvinyl butyral nanofibers and growth kinetics.  

PubMed

Electrospinning of hydroxyapatite (HA)/polyvinyl butyral solution resulted in the formation of fibers with average diameter of 937-1440 nm. These fibers were converted into HA nanoparticles with size <100 nm after undergoing calcination treatment at 600°C. The diameter of the fiber was found to be influenced by applied voltage and spinning distance. The injection flowrate did not affect the diameter significantly. The electrospinning method successfully reduced the commercial HA particle size in the range of 400-1100 nm into <100 nm. The dispersion of the finally calcined HA nanoparticles was improved significantly after anionic sodium dodecyl sulfate surfactant was introduced. The experimental data of HA growth kinetics were subjected to the integral method of analysis, and the rate law of the reaction was found to follow the first order reaction. PMID:23225849

Zakaria, Siti Maisurah; Sharif Zein, Sharif Hussein; Othman, Mohd Roslee; Jansen, John A

2013-07-01

462

Method of cross-linking polyvinyl alcohol and other water soluble resins  

NASA Technical Reports Server (NTRS)

A self supporting sheet structure comprising a water soluble, noncrosslinked polymer such as polyvinyl alcohol which is capable of being crosslinked by reaction with hydrogen atom radicals and hydroxyl molecule radicals is contacted with an aqueous solution having a pH of less than 8 and containing a dissolved salt in an amount sufficient to prevent substantial dissolution of the noncrosslinked polymer in the aqueous solution. The aqueous solution is then irradiated with ionizing radiation to form hydrogen atom radicals and hydroxyl molecule radicals and the irradiation is continued for a time sufficient to effect crosslinking of the water soluble polymer to produce a water insoluble polymer sheet structure. The method has particular application in the production of battery separators and electrode envelopes for alkaline batteries.

Phillipp, W. H.; May, C. E.; Hsu, L. C.; Sheibley, D. W. (inventors)

1980-01-01

463

Antimicrobial-coated polypropylene films with polyvinyl alcohol in packaging of fresh beef.  

PubMed

The utility of packaging films consisting of cast polypropylene/polyvinyl alcohol with rhubarb ethanolic extracts (REE) and cinnamon essential oil (CEO) in maintaining fresh beef quality was investigated. Fresh beefsteaks were packed with antimicrobial films containing different concentrations of REE and CEO. Beef characteristics, including pH, total viable counts, instrumentally measured color, weight loss, total volatile base nitrogen (TVB-N) and sensory quality were determined. All experimental films significantly inhibited bacterial growth (p<0.05) and maintained the pH and TVB-N of beefsteaks. Three of four experimental films significantly reduced instrumental color loss (p<0.05). Antimicrobial packaging films efficiently maintained the quality of fresh beefsteaks during storage. PMID:24211547

Han, Chunyang; Wang, Jianqing; Li, Yang; Lu, Fei; Cui, Yan

2014-02-01

464

Structure-property relationships in Sterculia urens/polyvinyl alcohol electrospun composite nanofibres.  

PubMed

Sterculia urens (Gum Karaya) based polyvinyl alcohol (PVA) composite nanofibres have been successfully electrospun after chemical modification of S. urens to increase its solubility. The effect of deacetylated S. urens (DGK) on the morphology, structure, crystallization behaviour and thermal stability was studied for spuned fibres before and after spinning post treatment. An apparent increase in the PVA crystallinity were observed in the PVA-DGK composite nanofibres indicating S. urens induced crystallization of PVA. The pure PVA nanofibre and the nanofibres of PVA-DGK composites were introduced to post electrospinning heat treatment at 150°C for 15min. The presence of sterculia gum reduced the fibre diameter and distribution of the nanofibres due to the increased stretching of the fibres during spinning. Switching of the thermal behaviour occurs due to post spinning heat treatments. PMID:25662689

Patra, Niranjan; Martinová, Lenka; Stuchlik, Martin; ?erník, Miroslav

2015-04-20

465

The effect of electron beam irradiation on preparation of sago starch/polyvinyl alcohol foams  

NASA Astrophysics Data System (ADS)

Blends of sago starch (SS)/polyvinyl alcohol (PVA) were irradiated with doses ranging from 10 to 30 kGy. Foams were then produced from these irradiated blends using a microwave. Changes in the degree of crosslinking, gel strength, thermal stability morphology of blends and linear expansion of foam with increasing irradiation doses were subsequently investigated. It was observed that the degree of crosslinking was important in maximizing the positive effect on foams produced. The gel strength of SS/PVA blends was affected by the irradiation. The crosslinking by the irradiation enhanced the thermal stability of SS/PVA blends. The results also revealed that the highest linear expansion of foams could be produced by irradiation blends at 15 kGy. Changes in blend morphology were observed upon irradiation.

Wongsuban, Benchamaporn; Muhammad, Kharidah; Ghazali, Zulkafli; Hashim, Kamaruddin; Ali Hassan, Muhammad

2003-10-01

466

Host-dependent optical dephasing of dye molecules doped in cross-linked polyvinyl alcohols  

NASA Astrophysics Data System (ADS)

Host-dependent optical dephasing of the zero-phonon line of two organic dye molecules doped in several cross-linked polyvinyl alcohol (PVA) derivatives was studied by using an incoherent photon echo technique. It was found that the optical dephasing time of the zero-phonon line increases with increasing the length of the cross-link introduced to the PVA backbone. Our results indicate that, by the introduction of the cross-link, the effect of the two-level tunneling system in PVA on optical dephasing of a doped dye is greatly reduced and the dephasing time of the dye becomes longer than that in the PVA without the cross-link. The decrease of the optical dephasing can be interpreted by assuming a void space in PVA, which is created near to an introduced cross-linker.

Kawase, M.; Fujiwara, S.; Nakanishi, S.; Itoh, H.

1992-07-01

467

PIXE investigation of in vitro release of chloramphenicol across polyvinyl alcohol/acrylamide hydrogel  

NASA Astrophysics Data System (ADS)

Hydrogels based on polyvinyl alcohol and different amounts of acrylamide monomer were prepared by thermal cross-linking in the solid state. The hydrogels were investigated for drug delivery system applications. Chloramphenicol was adopted as a model drug to study its release behavior. Particle induced X-ray emission was utilized to study the drug release behavior across the hydrogels and a comparison study with ultraviolet measurements was performed. Fourier Transform Infrared measurements were carried out for molecular characterization. The releasing behavior of the drug exhibits a decrease and a subsequent increase in the release rate, as the acrylamide monomer increases. Characterization of the hydrogels has shown a competitive behavior between crosslinking with AAm acrylamide monomer or oligomerized version, depending on the amount added to prepare the hydrogels.

Rihawy, M. S.; Alzier, A.; Allaf, A. W.

2011-09-01

468

Dye-doped polyvinyl alcohol recording materials for holography and nonlinear optics  

NASA Astrophysics Data System (ADS)

Photo-induced cross-linking polymers offer excellent properties, such as ease of handling, low cost, and real-time recording, for the application of holography and nonlinear optics. A vinyl polymer, namely, polyvinyl alcohol (PVA), has been chosen as a host matrix and is employed for holographic recording and nonlinear optics. Significant results of our experimental investigations on recording media fabricated by doping PVA with azo dyes and rhodamine 6G for real-time holographic recording and nonlinear optics are reported. The evaluation of third- order nonlinearities of azo dye/PVA systems and the characteristics of chrysoidine/PVA as a nonlinear waveguide are presented. Also, degenerate four-wave mixing experiments using a novel geometry have been carried out in rhodamine 6G/PVA films.

Lessard, Roger A.; Malouin, Christian; Changkakoti, Rupak; Manivannan, Gurusamy

1993-04-01

469

Development of clindamycin-loaded wound dressing with polyvinyl alcohol and sodium alginate.  

PubMed

To develop a clindamycin-loaded wound dressing, cross-linked hydrogel films were prepared using freeze-thawing method with various mixtures of polyvinyl alcohol (PVA) and sodium alginate (SA). The physicochemical properties such as swelling ratio, tensile strength and elongation of hydrogels were evaluated. The drug release from this clindamycin-loaded hydrogel, in vitro protein adsorption test and in vivo wound healing observations in rats were then performed. Increased SA concentration decreased the gelation %, maximum strength and break elongation, but it resulted into an increment in the swelling ability, elasticity and thermal stability of hydrogel film. However, SA had insignificant effect on the release of clindamycin. This hydrogel improved the healing rate of artificial wounds in rats. Thus, a clindamycin-loaded wound dressing with PVA and SA hydrogel should be a candidate for wound care. PMID:19043213

Kim, Jong Oh; Choi, Jun Young; Park, Jung Kil; Kim, Jeong Hoon; Jin, Sung Giu; Chang, Sun Woo; Li, Dong Xun; Hwang, Ma-Ro; Woo, Jong Soo; Kim, Jung-Ae; Lyoo, Won Seok; Yong, Chul Soon; Choi, Han-Gon

2008-12-01

470

Performance of large diameter polyvinyl chloride (PVC) pipes in water applications  

NASA Astrophysics Data System (ADS)

Polyvinyl chloride (PVC) pipes are used in water management utilities to manage safe and efficient water transport. The material's advantages includes strength, flexibility, anti-corrosive properties and easy installation methods. The disadvantages include joint failure, pipe fractures, material contamination and oxidative degradation. This thesis evaluates the use of 24 inch and larger diameter PVC pipes in water management utilities. Center of Undergraduate Infrastructure and Research Education (CUIRE) conducted surveys consisting of questions pertaining to PVC pipe material and installation practices to different water management utilities. While PVC material is most commonly used in pipelines less than 24", the CUIRE responses show that PVC pipes are not the most common type of pipe material in 24" and larger diameters installed in the facilities for various reasons. These reasons are discussed and evaluated in hopes of understanding the material's fallbacks in the piping industry. Finally, future research recommendations are constructed for researchers in the PVC piping industry.

Deshmukh, Pradip P.

471

Structural dependence of silver nanowires on polyvinyl pyrrolidone (PVP) chain length  

NASA Astrophysics Data System (ADS)

The effect of the chain length of polyvinyl pyrrolidone (PVP) on the structures of silver nanowires (AgNWs) is explored in this study. It was found in the experiments that PVP, when serving as a capping agent, has a great impact on the morphology and structure of AgNWs. By means of a series of experiments and the inquiry of the growth mechanism, the critical minimum PVP chain length for the successful formation of uniform nanowires was discovered, below which only nanoparticles or short nanorods can be obtained. Surprisingly, a core–shell structure of a nanowire with a polycrystal was observed when PVP with a very long chain length was employed in the processing.

Zeng, Xiping; Zhou, Bingpu; Gao, Yibo; Wang, Cong; Li, Shunbo; Yeung, Chau Yeung; Wen, WeiJia

2014-12-01

472

Structural dependence of silver nanowires on polyvinyl pyrrolidone (PVP) chain length.  

PubMed

The effect of the chain length of polyvinyl pyrrolidone (PVP) on the structures of silver nanowires (AgNWs) is explored in this study. It was found in the experiments that PVP, when serving as a capping agent, has a great impact on the morphology and structure of AgNWs. By means of a series of experiments and the inquiry of the growth mechanism, the critical minimum PVP chain length for the successful formation of uniform nanowires was discovered, below which only nanoparticles or short nanorods can be obtained. Surprisingly, a core-shell structure of a nanowire with a polycrystal was observed when PVP with a very long chain length was employed in the processing. PMID:25407502

Zeng, Xiping; Zhou, Bingpu; Gao, Yibo; Wang, Cong; Li, Shunbo; Yeung, Chau Yeung; Wen, WeiJia

2014-12-12

473

Catalytic oxidation of butyl acetate over silver-loaded zeolites.  

PubMed

The performance of silver-loaded zeolite (HY and HZSM-5) catalysts in the oxidation of butyl acetate as a model volatile organic compound (VOC) was studied. The objective was to find a catalyst with superior activity, selectivity towards deep oxidation product and stability. The catalyst activity was measured under excess oxygen condition in a packed bed reactor operated at gas hourly space velocity (GHSV)=15,000-32,000 h(-1), reaction temperature between 150 and 500 degrees C and butyl acetate inlet concentration of 1000-4000 ppm. Both AgY and AgZSM-5 catalysts exhibited high activity in the oxidation of butyl acetate. Despite lower silver content, AgY showed better activity, attributed to better metal dispersion, surface characteristics and acidity, and its pore system. Total conversion of butyl acetate was achieved at above 400 degrees C. The oxidation of butyl acetate followed a simple power law model. The reaction orders, n and m were evaluated under differential mode by varying the VOC partial pressure between 0.004 and 0.018 atm and partial pressure of oxygen between 0.05 and 0.20 atm. The reaction rate was independent of oxygen concentration and single order with respect to VOC concentration. The activation energies were 19.78 kJ/mol for AgY and 32.26 kJ/mol for AgZSM-5, respectively. PMID:18294771

Wong, Cheng Teng; Abdullah, Ahmad Zuhairi; Bhatia, Subhash

2008-09-15

474

[Conversion of acetic acid to methane by thermophiles: Progress report  

SciTech Connect

The objective of this project is to provide an understanding of thermophilic anaerobic microorganisms capable of breaking down acetic acid, the precursor of two-thirds of the methane produced by anaerobic bioreactors. Recent results include: (1) the isolation of Methanothrix strain CALLS-1, which grows much more rapidly than mesophilic strains; (2) the demonstration that thermophilic cultures of Methanosarcina and Methanothrix show minimum thresholds for acetate utilization of 1--2.5 mM and 10--20{mu}m respectively, in agreement with ecological data indicating that Methanothrix is favored by low acetate concentration; (3) the demonstration of high levels of thermostable acetyl-coA synthetase and carbon monoxide dehydrogenase in cell-free extracts of Methanothrix strains CALS-1; (4) the demonstration of methanogenesis from acetate and ATP in cell free extracts of strain CALS-1. (5) the demonstration that methanogenesis from acetate required 2 ATP/methane, and, in contrast to Methanosarcina, was independent of hydrogen and other electron donors; (6) the finding that entropy effects must be considered when predicting the level of hydrogen in thermophilic syntrophic cultures. (7) the isolation and characterization of the Desulfotomaculum thermoacetoxidans. Current research is centered on factors which allow thermophilic Methanothrix to compete with Methanosarcina.

Zinder, S.

1991-12-31

475

(Conversion of acetic acid to methane by thermophiles: Progress report)  

SciTech Connect

The objective of this project is to provide an understanding of thermophilic anaerobic microorganisms capable of breaking down acetic acid, the precursor of two-thirds of the methane produced by anaerobic bioreactors. Recent results include: (1) the isolation of Methanothrix strain CALLS-1, which grows much more rapidly than mesophilic strains; (2) the demonstration that thermophilic cultures of Methanosarcina and Methanothrix show minimum thresholds for acetate utilization of 1--2.5 mM and 10--20{mu}m respectively, in agreement with ecological data indicating that Methanothrix is favored by low acetate concentration; (3) the demonstration of high levels of thermostable acetyl-coA synthetase and carbon monoxide dehydrogenase in cell-free extracts of Methanothrix strains CALS-1; (4) the demonstration of methanogenesis from acetate and ATP in cell free extracts of strain CALS-1. (5) the demonstration that methanogenesis from acetate required 2 ATP/methane, and, in contrast to Methanosarcina, was independent of hydrogen and other electron donors; (6) the finding that entropy effects must be considered when predicting the level of hydrogen in thermophilic syntrophic cultures. (7) the isolation and characterization of the Desulfotomaculum thermoacetoxidans. Current research is centered on factors which allow thermophilic Methanothrix to compete with Methanosarcina.

Zinder, S.

1991-01-01

476

The Metabolism of Acetate by the Blue-green Algae, Anabaena variabilis and Anacystis nidulans  

Microsoft Academic Search

SUMMARY The utilization of acetate by blue-green algae was examined and the activities of enzymes involved in its metabolism measured. Although acetate did not stimulate the endogenous respiration of these organisms, the oxida- tion of acetate was followed by the rate of release of (14C) carbon dioxide from (I-~~CC) and (2-l4CC) sodium acetate. Similarly, sodium acetate did not alter the

J. Pearce; N. G. Carr

1967-01-01

477

[Preparation and characterization of polyvinyl alcohol microsphere pre-coated dynamic membranes].  

PubMed

To alleviate membrane fouling and reduce the price of membrane module, polyvinyl alcohol microsphere pre-coated dynamic membranes (PVA-MS/PCDMs) were investigated detailedly. It was prepared when the polyvinyl alcohol microsphere of the pre-coated reagent deposited on the surface and entered the pores of porous substrate common filter cloth which was low-cost by means of circulatory filtration. The morphology and structure of PVA-MS/PCDMs were examined using scanning electron microscope (SEM), and approximate maximal separated aperture, water contact angle, pure water permeation resistance and relative Zeta potential of the membrance surface were also determined. The results showed that pure water permeation resistance of PVA-MS/PCDMs was between 0.64 x 10(10) m(-1) and 3.84 x 10(10) m(-1) and the approximate maximal separated aperture reached microfiltration level. The hydrophilicity of PVA-MS/PCDMs increased with increasing PVA-MS pre-coated mass. The relative Zeta potential of the PVA-MS/PCDMs, which were measured using 0.01 mol x L(-1) KCl solution, pH 8.0 +/- 0.2 and at 20 degrees C, reached a peak value of -36.4 mV with pre-coated mass of 15.7 g x m(-2) PVA-MS on the membrance surface. In addition, evolutions of PVA-MS/PCDMs flux versus time were investigated using a 4 hours short-term filtration experiment at 9.5 kPa in an SMBR and the permeability coefficient of PVA-MS/PCDMs were measured by the extracellular polymeric substances (EPS) diffusion experiments. Results indicated that the PVA-MS/PCDMs presented dramatically high anti-fouling characteristics when the pre-coated mass of PVA-MS was 23.9-61.9 g x m(-2). PMID:19774996

Wang, Jiang-Wei; Zhang, Han-Min; Ye, Mao-Sheng; Yang, Feng-Lin

2009-07-15

478

Improvement of productivity in acetic acid fermentation with Clostridium thermoaceticum  

SciTech Connect

Production of acetic acid by a mutant strain of Clostridium thermoaceticum was compared in three types of membrane cell-recycle bioreactors. A modified fed-batch bioreactor (where the product is partially removed at the end of fermentation, but the cells are retained), and a two-stage CSTR (with product being removed continuously and the cells being recycled from the second to the first stage) resulted in better performance than a one-stage CSTR or batch fermenter. The difference in performance was greater at higher acetate concentration. With 45 g/L of glucose in the feed, productivity was 0.75-1.12 g/L-h and acetic acid concentrations were 34-38 g/L. This is more than double the batch system. The nutrient supply rate also appeared to have a strong influence on productivity of the microorganism.

Shah, M.M.; Cheryan, M. [Univ. of Illinois, Urbana, IL (United States)

1995-12-31

479

Photoionization of small sodium-doped acetic acid clusters.  

PubMed

The uptake of sodium and the fragmentation before and after "soft" photoionization with ultraviolet light are investigated for small acetic acid clusters. The acetic acid clusters are generated in a supersonic expansion and ionized with ultraviolet light after doping with sodium in a pick-up chamber. The composition of the bare acetic acid clusters in the molecular beam is determined independently from complementary photoionization experiments using extreme ultraviolet light. The experimental results are analyzed with the help of density functional calculations for energetics and statistical adiabatic channel calculations for fragmentation kinetics. The study demonstrates that the detected ions originate from fragmentation in the neutral as well as in the ionic state, and in particular that the fragmentation pathway strongly depends on the cluster size. PMID:21384976

Forysinski, Piotr W; Zielke, Philipp; Luckhaus, David; Corbett, Jennifer; Signorell, Ruth

2011-03-01

480

Functionalization of cellulose acetate fibers with engineered cutinases.  

PubMed

In the present work, we describe for the first time the specific role of cutinase on surface modification of cellulose acetate fibers. Cutinase exhibits acetyl esterase activity on diacetate and triacetate of 0.010 U and 0.007 U, respectively. An increase on the hydroxyl groups at the fiber surface of 25% for diacetate and 317% for triacetate, after a 24 h treatment, is estimated by an indirect assay. Aiming at further improvement of cutinase affinity toward cellulose acetate, chimeric cutinases are genetically engineered by fusing the 3'-end coding sequence with a bacterial or a fungal carbohydrate-binding module and varying the linker DNA sequence. A comparative analysis of these genetic constructions is presented showing that, the superficial regeneration of cellulose hydrophilicity and reactivity on highly substituted cellulose acetates is achieved by chimeric cutinases. PMID:20014432

Matamá, Teresa; Araújo, Rita; Gübitz, Georg M; Casal, Margarida; Cavaco-Paulo, Artur

2010-01-01

481

Disinfection of mung bean seed with gaseous acetic acid.  

PubMed

Mung bean seed inoculated with Salmonella Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes (3 to 5 log CFU/g) was exposed to gaseous acetic acid in an aluminum fumigation chamber. Salmonella Typhimurium and E. coli O157:H7 were not detected by enrichment of seeds treated with 242 microl of acetic acid per liter of air for 12 h at 45 degrees C. L. monocytogenes was recovered by enrichment from two of 10 25-g seed samples treated in this manner. Fumigation with gaseous acetic acid was also lethal to indigenous bacteria and fungi on mung bean seed. The treatment did not significantly reduce seed germination rates, and no differences in surface microstructure were observed between treated and untreated seed viewed by scanning electron microscopy. PMID:10456753

Delaquis, P J; Sholberg, P L; Stanich, K

1999-08-01

482

[Conversion of acetic acid to methane by thermophiles  

SciTech Connect

The primary goal of this project is to obtain a better understanding of thermophilic microorganisms which convert acetic acid to CH[sub 4]. The previous funding period represents a departure from earlier research in this laboratory, which was more physiological and ecological. The present work is centered on the biochemistry of the thermophile Methanothrix sp. strain CALS-1. this organism presents a unique opportunity, with its purity and relatively rapid growth, to do comparative biochemical studies with the other major acetotrophic genus Methanosarcina. We previously found that Methanothrix is capable of using acetate at concentrations 100 fold lower than Methanosarcina. This finding suggests that there are significant differences in the pathways of methanogenesis from acetate in the two genera.

Zinder, S.H.

1993-01-01

483

Multi-core cable-like TiO2 nanofibrous membranes for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Multi-core cable-like TiO2 nanofibres were fabricated by calcination of composite polyvinyl acetate (PVAc)/titania nanofibres with a hot pressing pre-treatment. This resultant novel fibre structure was composed of sheaths of 200 nm in diameter and 25 nm in wall thickness, and cores filled with 24 nm thick TiO2 fibrils. The formation of multi-core cable-like structures of fibres is considered to be due to the enhanced phase separation of PVAc-rich and TiO2-rich phases during the hot pressing process. The BET results showed that the specific surface area of pressed TiO2 membranes was much higher than that of unpressed TiO2 membranes. In this study, the novel multi-core cable-like TiO2 fibrous membranes were used as electrode materials for dye-sensitized solar cells (DSSCs). It was observed that the photocurrent and conversion efficiency of the electrodes increased concurrently with increasing applied pressure and average membrane thickness in the range of 1-9 µm. The maximum short circuit photocurrent and energy conversion efficiency were 16.09 mA cm-2 and 5.77% when the membrane had an average thickness of 9.21 µm and 8 MPa applied pressure.

Kokubo, Hiroshi; Ding, Bin; Naka, Takayuki; Tsuchihira, Hiroki; Shiratori, Seimei

2007-04-01

484

Evaluation of vinyl laurate in a battery of in vitro and in vivo tests for genotoxicity.  

PubMed

Vinyl laurate is a potential residual monomer in chewing gum base formulated with polyvinyl acetate vinyl laurate copolymer (PVAcVL). The genotoxic potential of vinyl laurate was examined in a battery of in vitro and in vivo genotoxicity tests. Vinyl laurate was not mutagenic in Ames tests. In addition, it was not mutagenic in the HPRT mutation assay in L5178Y cells. An in vitro mammalian chromosome aberration assay performed in CHO cells was equivocal. Vinyl laurate and/or its metabolites were not clastogenic in the mouse bone marrow micronucleus test. Kinetic data indicate that VL is metabolised to acetaldehyde and lauric acid. Both metabolites are well known and have been studied previously. Model calculations show, that any exposure to acetaldehyde from the consumption of PVAcVL containing chewing gum will remain far below levels of acetaldehyde exposure from food in which acetaldehyde occurs naturally. Direct exposure to VL will primarily be at the site of entry. The lack of toxicity in a 90-day repeated dose toxicity test, performed with VL doses up to approximately 3000 times higher than the maximal VL intake from the consumption of a typical piece of chewing gum, demonstrates a high safety margin. PMID:25445001

van Acker, Frédérique; Messinger, Horst; Bär, Albert

2014-10-31

485

Nanodomain formation in a liquid polymer blend: The initial stages of phase separation  

SciTech Connect

The morphology of nanodomain structures in binary polymer blends of a random copolymer and a homopolymer is determined using electronic excitation transport (EET) studies. The experimental system employed is a copolymer, 6.5% atactic poly(methyl methacrylate-{ital co}-2-vinyl naphthalene) [P(MMA-2VN)], in atactic poly(vinyl acetate) (PVAc). The naphthalene groups serve as chromophores in the EET experiments. The mixtures are prepared such that initially the P(MMA-2VN) chains are randomly distributed in the PVAc matrix. The nanodomains are formed while low-concentration mixtures of the P(MMA-2VN) in PVAc are held at constant temperature in the melt state ({ital T}{gt}{ital T}{sub {ital g}}), above the temperature at which phase separation occurs. In the melt the chains diffuse, and P(MMA-2VN) chains aggregate until the temperature is quenched below {ital T}{sub {ital g}}. The structures of the resulting domains are examined with time-resolved fluorescence depolarization measurements, and the data are analyzed using an analytical theory to model EET among interacting polymer chains. The agreement between theory and data is very good. The results of the analysis indicate that the nanodomains correspond to aggregates with a characteristic size equal to the radius of gyration of the copolymer, {ital R}{sub {ital g}}. The number of P(MMA-2VN) chains in aggregates prepared under different conditions is determined. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Marcus, A.H.; Hussey, D.M.; Diachun, N.A.; Fayer, M.D. [Department of Chemistry, Stanford University, Stanford, California 94305 (United States)] [Department of Chemistry, Stanford University, Stanford, California 94305 (United States)

1995-11-08

486

Delineation of LASIK Flaps with Prednisolone Acetate Eyedrops  

PubMed Central

We describe the use and safety of prednisolone acetate eyedrops at the end of laser in situ keratomileusis (LASIK) to aid proper positioning of the corneal flap. The LASIK flap is created using the preferred technique. Following laser ablation and flap repositioning, one drop of prednisolone acetate is instilled on the eye. This delineates the flap “gutters” and allows perfect flap positioning and centration. We used this technique in 425 eyes undergoing LASIK for correction of spherocylindrical refractive errors. Flap margins were adequately delineated intraoperatively. The only complication related to the use of the steroid suspension was crystal deposition under the flap in one case which resolved completely in 48 hours. PMID:24982743

Fahd, Daoud C; Fahed, Sharbel D

2014-01-01

487

Investigation of Pyrolyses of Benzyl Benzoate, Acetate and Formate  

Microsoft Academic Search

The pyrolysis of benzyl benzoate, benzyl acetate, and benzyl formate has been studied by means of ``toluene carrier gas'' technique. It has been shown that benzyl-benzoate decomposes according to the equation Ph·CH2·O·CO·Ph?Ph·CH2·+Ph·COO. The Ph·CH2&sngbnd;O·CO·Ph bond dissociation energies have been estimated as less than 69 kcal\\/mole. Decompositions of benzyl acetate and of benzyl formate are more complicated; the dissociation into radicals

M. Szwarc; J. Watson Taylor

1953-01-01

488

[Ice application for reducing pain associated with goserelin acetate injection].  

PubMed

We investigated the effectiveness of using an ice pack for reducing the pain associated with goserelin acetate injection. In this study, 39 patients with prostate cancer and 1 patient with breast cancer receiving hormonal therapy with goserelin acetate were enrolled. All patients completed a questionnaire regarding the use of ice application. We used the numerical rating scale (NRS) to assess the pain associated with injection. The NRS scores indicated that the pain was significantly less with ice application than with the usual method (p < 0.001). Further, ice application could decrease the duration of pain sensation. Ice application at the injection site is safe and effective for reducing pain. PMID:24105059

Ishii, Kaname; Nagata, Chika; Koshizaki, Eiko; Nishiuchi, Satoko

2013-10-01

489

Synthesis of radiolabeled acetyl-coenzyme A from sodium acetate  

SciTech Connect

The synthesis of high specific radioactivity (/sup 14/C)-acetyl-Coenzyme A from (/sup 14/C)sodium acetate, 2,6-dichlorobenzoic acid, 1,1'-carbonyldiimidazole, and CoA is reported. Starting with 1 mumol of (/sup 14/C)sodium acetate, this method yields pure (/sup 14/C)acetyl-CoA in yields approaching 40%. Chromatography on a reversed-phase ODS column was used to separate acetyl-CoA from Coenzyme A and side products. The acetylating agent is apparently a reaction intermediate, acetylimidazole.

Clough, R.C.; Barnum, S.R.; Jaworski, J.G.

1989-01-01

490

First synthesis and characterization for the stereoisomers of Ulipristal acetate.  

PubMed

The three stereoisomers, 11?,17?-isomer I, 11?,17?-isomer II and 11?,17?-isomer III are related substances of the selective progesterone receptor modulator Ulipristal acetate. Herein, we presented an efficient and practical synthesis approach to deliver these three stereoisomers for the first time, and also confirmed the structure of the key intermediate 5a by single-crystal X-ray analysis. Our research will be of immense help for organic chemists to study the impurity profile of Ulipristal acetate. PMID:25554579

Zhao, Yi; Li, Xiaolong; Liu, Hong; Yu, Yongguo; Hai, Li; Guo, Li; Wu, Yong

2015-03-01

491

Kanokonyl acetate-rich Indian valerian from northwestern Himalaya.  

PubMed

The volatile composition of rhizomes of Valeriana wallichii DC has been studied by GC, GC/MS and NMR spectroscopy. Sesquiterpenes were shown to be the main constituents (> 89.3%) comprising kanokonyl acetate (42.4%), gamma-curcumene (10.7%), ar-curcumene (7.2%), (Z)-beta-farnesene (3.2%), xanthorrhizol (4.1%), 7-epi-alpha-selinene (2.2%), valeranone (2.0%) and curcuphenol (1.4%). The unique presence of kanokonyl acetate and the complete absence of the earlier reported chemotype marker constituents of Indian valerian viz. maaliol and patchouli alcohol makes the composition significant. PMID:19831039

Mathela, Chandra S; Padalia, Rajendra C; Chanotiya, Chandan S

2009-09-01

492

A Heterogeneously Structured Composite Based on Poly(lactic-co-glycolic acid) Microspheres and Poly(vinyl alcohol) Hydrogel Nanoparticles for Long-Term Protein Drug Delivery  

Microsoft Academic Search

Purpose. To prepare a heterogeneously structured composite based on poly (lactic-co-glycolic acid) (PLGA) microspheres and poly(vinyl alcohol) (PVA) hydrogel nanoparticles for long-term protein drug delivery.

Nuo Wang; XueShen Wu; JiaKui Li

1999-01-01

493

Fate and residues of trenbolone acetate in edible tissues from sheep amd calves implanted with tritium-labeled trenbolone acetate  

SciTech Connect

In order to study the fate and residues of trenbolone acetate in edible tissues, two groups of six animals from two ruminant species (ewes and calves) were implanted with (3H)trenbolone acetate. The distribution of extractable radioactive residues was measured in liver, kidney and muscle. We found that the largest proportion of residues was not extractable and thus was considered as covalently bound residues. The proportion of the main extractable metabolites (17 alpha-trenbolone, trendione, 17 beta-trenbolone) was measured. The evaluation of the distribution of trenbolone acetate metabolites directly soluble in water showed that unknown metabolite(s) were predominant. The covalent binding to nucleic acids was measured. It was so low that it was not detectable. The results are discussed in light of the data presented in the scientific report on anabolic agents in animal production from the European scientific working group.

Evrard, P.; Maghuin-Rogister, G.; Rico, A.G. (Univ. of Liege (Belgium))

1989-06-01

494

Effect of the polymer concentration on the ON/OFF states of a TN-LCD: polyvinyl alcohol vs. soy lecithin  

NASA Astrophysics Data System (ADS)

In this work we study the response of a Twisted Nematic Liquid Crystal Display (TN-LCD) by varying both the concentration and the polymer used for the microgroove. We compare the performance of two polymers: polyvinyl alcohol and soy lecithin. In particular, the light transmission for the ON/OFF states is evaluated. The polyvinyl alcohol is a polymer widely used in LCDs while lecithin soy is a natural polymer.

de Coss Martinez, Romeo; Gonzalez Murguia, Jose Luis

2011-03-01

495

Water and toluene resistance and mechanical properties of semi-interpenetrating polymer network based on epoxided NR or NR and polyvinyl alcohol blends containing maleic acid as crosslinking  

Microsoft Academic Search

Recently, natural rubber (NR) and its derivative as renew able and biodegradable material have attracted considerable attention because of the serious pollution problems caused by synthetic materials and shortage of resources. In the present study we prepare the semi-interpenetrating polymer network (semi-IPN) based on NR\\/polyvinyl alcohol (NR\\/PVA) or epoxidise NR\\/polyvinyl alcolhol (ENR\\/PVA) to make the surface possessing those interesting properties

Sa-ad Riyajan; Suwit Chaiphonban

496

Encapsulation of the peptide Ac–Glu–Thr–Lys–Thr–Tyr–Phe–Trp–Lys–NH 2 into polyvinyl alcohol biodegradable formulations—Effect of calcium alginate  

Microsoft Academic Search

It has been recently reported that the peptide Ac–Glu–Thr–Lys–Thr–Tyr–Phe–Trp–Lys–NH2, analogue of the Glu1811–Lys1818 region of A3 light chain of blood coagulation factor VIII, presents in vitro significant anticoagulant activity. The encapsulation of this peptide into different polyvinyl alcohol formulations is examined here. The formulations were prepared using polyvinyl alcohol cross-linked with either boric acid or glutaraldehyde, giving a series of

Konstantinos Patsialas; Emmanouil H. Papaioannou; Maria Liakopoulou-Kyriakides

497

Linalyl Acetate Is Metabolized by Pseudomonas incognita with the Acetoxy Group Intact  

PubMed Central

Metabolism of linalyl acetate by Pseudomonas incognita isolated by enrichment culture on the acyclic monoterpene alcohol linalool was studied. Biodegradation of linalyl acetate by this strain resulted in the formation of linalool, linalool-8-carboxylic acid, oleuropeic acid, and ?5-4-acetoxy-4-methyl hexenoic acid. Cells adapted to linalyl acetate metabolized linalyl acetate-8-aldehyde to linalool-8-carboxylic acid, linalyl acetate-8-carboxylic acid, ?5-4-acetoxy-4-methyl hexenoic acid, and geraniol-8-carboxylic acid. Resting cell suspensions previously grown with linalyl acetate oxidized linalyl acetate-8-aldehyde to linalyl acetate-8-carboxylic acid, ?5-4-acetoxy-4-methyl hexenoic acid, and pyruvic acid. The crude cell-free extract (10,000 g of supernatant), obtained from the sonicate of linalyl acetate-grown cells, was shown to contain enzyme systems responsible for the formation of linalyl acetate-8-carboxylic acid and linalool-8-carboxylic acid from linalyl acetate. The same supernatant contained NAD-linked alcohol and aldehyde dehydrogenases involved in the formation of linalyl acetate-8-aldehyde and linalyl acetate-8-carboxylic acid, respectively. On the basis of various metabolites isolated from the culture medium, resting cell experiments, growth and manometric studies carried out with the isolated metabolites as well as related synthetic analogs, and the preliminary enzymatic studies performed with the cell-free extract, a probable pathway for the microbial degradation of linalyl acetate with the acetoxy group intact is suggested. PMID:16346182

Renganathan, V.; Madyastha, K. Madhava

1983-01-01

498

Analysis of thermal decomposition products arising from polyvinyl chloride analogs by supersonic jet/multiphoton ionization/mass spectrometry.  

PubMed

Polyvinyl chloride (PVC) and chlorinated polyvinyl chloride (CPVC) were thermally decomposed at 200-500 degrees C, and the reaction products measured by supersonic jet/multiphoton ionization/mass spectrometry. No precursor molecules of dioxins, such as chlorobenzene, were observed from PVC, although benzene was produced as one of the major components. On the other hand, a large peak corresponding to chlorobenzene was observed, when CPVC was used as a sample. These results suggest that the release of hydrogen chloride and aromatic ring formation occur efficiently and produce chlorinated aromatic hydrocarbons only when excess chlorine atoms are present in the chain of PVC. This method, which has very high selectivity is preferred for trace analysis of specific compounds such as dioxin precursors in a complex mixture. Isomer-selective analysis, e.g. detection of o-, m-, and p-dichlorobenzenes, is also demonstrated in this study. PMID:18968029

Urabe, T; Imasaka, T

2000-07-31

499

Novel hydrogels of chitosan and poly(vinyl alcohol)-g-glycolic acid copolymer with enhanced rheological properties.  

PubMed

Poly(vinyl alcohol) (PVA) has been grafted with glycolic acid (GL), a biodegradable hydroxyl acid to yield modified poly(vinyl alcohol) (PVAGL). The formation of hydrogels at pH = 6.8 and physiological temperature through blending chitosan (CS) and PVAGL at different concentrations has been investigated. FTIR, DOSY NMR and oscillatory rheology measurements have been carried out on CS/PVAGL hydrogels and the results have been compared to those obtained for CS/PVA hydrogels prepared under the same conditions. The experimental results point to an increase in the number of interactions between chitosan and PVAGL in polymer hydrogels prepared with modified PVA. The resulting materials with enhanced elastic properties and thixotropic behavior are potential candidates to be employed as injectable materials for biomedical applications. PMID:24528729

Lejardi, A; Hernández, R; Criado, M; Santos, Jose I; Etxeberria, A; Sarasua, J R; Mijangos, C

2014-03-15

500

PROCESS FOR OBTAINING CELLULOSE ACETATE FROM AGRICULTURAL BY-PRODUCTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

A method of preparation of commercially useful product, cellulose acetate from discarded byproducts such as rice-straw, wheat hull and corn fiber will be discussed. This work will provide potential new markets and applications for low-value agricultural wastes and co-products. By converting the ce...