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Sample records for clinical polymer gel

  1. Water equivalence of polymer gel dosimeters

    International Nuclear Information System (INIS)

    To evaluate the water equivalence and radiation transport properties of polymer gel dosimeters over the wide range of photon and electron energies 14 different types of polymer gels were considered. Their water equivalence was evaluated in terms of effective atomic number (Zeff), electron density (ρe), photon mass attenuation coefficient (μ/ρ), photon mass energy absorption coefficient (μen/ρ) and total stopping power (S/ρ)tot of electrons using the XCOM and the ESTAR database. The study showed that the effective atomic number of polymer gels were very close (en/ρ for all polymer gels were in close agreement (tot of electrons in polymer gel dosimeters were within 1% agreement with that of water. From the study we conclude that at lower energy (<80keV) the polymer gel dosimeters cannot be considered water equivalent and study has to be carried out before using the polymer gel for clinical application

  2. Active Polymer Gel Actuators

    Directory of Open Access Journals (Sweden)

    Shuji Hashimoto

    2010-01-01

    Full Text Available Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of heart muscles. Here we show a novel biomimetic gel actuator that can walk spontaneously with a wormlike motion without switching of external stimuli. The self-oscillating motion is produced by dissipating chemical energy of oscillating reaction. Although the gel is completely composed of synthetic polymer, it shows autonomous motion as if it were alive.

  3. Active Polymer Gel Actuators

    OpenAIRE

    Shuji Hashimoto; Ryo Yoshida; Yusuke Hara; Shingo Maeda

    2010-01-01

    Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of he...

  4. Water equivalence of polymer gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Sellakumar, P. [Bangalore Institute of Oncology, 44-45/2, II Cross, RRMR Extension, Bangalore-560 027 (India)]. E-mail: psellakumar@rediffmail.com; James Jebaseelan Samuel, E. [School of Science and Humanities, Vellore Institute of Technology, Vellore-632 014 (India); Supe, Sanjay S. [Kidwai Memorial Institute of Oncology, Hosur Road, Bangalore-560 027 (India)

    2007-07-15

    To evaluate the water equivalence and radiation transport properties of polymer gel dosimeters over the wide range of photon and electron energies 14 different types of polymer gels were considered. Their water equivalence was evaluated in terms of effective atomic number (Z{sub eff}), electron density ({rho}{sub e}), photon mass attenuation coefficient ({mu}/{rho}), photon mass energy absorption coefficient ({mu}{sub en}/{rho}) and total stopping power (S/{rho}){sub tot} of electrons using the XCOM and the ESTAR database. The study showed that the effective atomic number of polymer gels were very close (<1%) to that of water except PAGAT, MAGAT and NIPAM which had the variation of 3%, 2% and 3%, respectively. The value of {mu}/{rho} and {mu}{sub en}/{rho} for all polymer gels were in close agreement (<1%) with that of water beyond 80keV. The value of (S/{rho}){sub tot} of electrons in polymer gel dosimeters were within 1% agreement with that of water. From the study we conclude that at lower energy (<80keV) the polymer gel dosimeters cannot be considered water equivalent and study has to be carried out before using the polymer gel for clinical application.

  5. Topical Review: Polymer gel dosimetry

    OpenAIRE

    Baldock, C; De Deene, Y; Doran, S.; Ibbott, G; Jirasek, A.; Lepage, M.; McAuley, K B; Oldham, M; Schreiner, L J

    2010-01-01

    Polymer gel dosimeters are fabricated from radiation sensitive chemicals which, upon irradiation, polymerize as a function of the absorbed radiation dose. These gel dosimeters, with the capacity to uniquely record the radiation dose distribution in three-dimensions (3D), have specific advantages when compared to one-dimensional dosimeters, such as ion chambers, and two-dimensional dosimeters, such as film. These advantages are particularly significant in dosimetry situations where steep dose ...

  6. 3-dimensional polymer gel dosimetry

    International Nuclear Information System (INIS)

    Recently developed techniques in conformal radiotherapy demand special properties of radiation dosimeters. Polymer gel dosimeter evaluated by nuclear magnetic resonance (NMR) is promising tool which can be used for measuring rather complicated 3-dimensional dose distributions with required precision of ± 5 %. This system is based on radiation-induced polymerisation and cross-linking of acrylic monomers which are uniformly dispersed in aqueous gel. The formation of cross-linked polymers in the irradiated regions of the gel increases the NMR relaxation rates of neighbouring water protons. BANG-2 type polymer gel was prepared. The composition of gel dosimeter was as follows: 3 % N,N'-methylene-bisacrylamide, 3 % acrylic acid, 1 % sodium hydroxide, 5 % gelatine, and 88 % water, where all percentages are by weight. The dosimeters in glass vessels were homogeneously irradiated by 60Co gamma photons in a Gammacell 220 unit and by 4 MV, 6 MV and 18 MV X ray photons on Varian Clinac 600C and 2100 C linear accelerators by doses in the range of 0-50 Gy. Evaluation of dosimeters was performed on Siemens EXPERT 1 T and Siemens VISION 1,5 T scanners. Multi-echo CPMG sequence with 16 echoes was used for the evaluation of T2-relaxation times in irradiated gel dosimeters. The dependence of 1/T2 response of dosimeters was studied on following factors: absorbed dose, energy of applied radiation, temperature during NMR evaluation, time since irradiation to NMR evaluation and strength of the magnetic field. An exponential dependence of 1/T2 response on absorbed dose in the range of 0-50 Gy was observed, in the range 0-10 Gy the data could be fitted by a linear function. There was observed no dependence of 1/T2 response on: energy (for three different photon energies used in this study), strength of magnetic field of NMR scanner, time from irradiation of the dosimeters to NMR evaluation. Increase of gel dosimeter 1/T2 response with the decrease of the temperature during NMR evaluation

  7. Conductivity behaviour of polymer gel electrolytes: Role of polymer

    Indian Academy of Sciences (India)

    S S Sekhon

    2003-04-01

    Polymer is an important constituent of polymer gel electrolytes along with salt and solvent. The salt provides ions for conduction and the solvent helps in the dissolution of the salt and also provides the medium for ion conduction. Although the polymer added provides mechanical stability to the electrolytes yet its effect on the conductivity behaviour of gel electrolytes as well as the interaction of polymer with salt and solvent has not been conclusively established. The conductivity of lithium ion conducting polymer gel electrolytes decreases with the addition of polymer whereas in the case of proton conducting polymer gel electrolytes an increase in conductivity has been observed with polymer addition. This has been explained to be due to the role of polymer in increasing viscosity and carrier concentration in these gel electrolytes.

  8. Polymer gel dosimetry system for radiation therapy

    International Nuclear Information System (INIS)

    Purpose/Objective: Recently developed treatment modalities such as stereotactic and conformal radiation therapy produce complex dose distributions which are difficult or impractical to measure with conventional dosimetry instrumentation. Three-dimensional treatment planning systems which purport to calculate these complex dose distributions should be compared to experimental results before being routinely applied to clinical problems. There is a need for a new class of tissue-equivalent dosimeters capable of providing accurate, high resolution, time-integrated and three dimensional dose distributions. The recently developed BANG polymer gel dosimetry system (MGS Research, Inc., Guilford, CT) is ideally suited for the task described above. Physico-chemical principles of the polymer gel dosimetry are presented, together with examples of its application to radiation therapy. Data analysis and display program, written for Macintosh computer, is demonstrated. Materials and Methods: Radiation-induced polymerization of acrylic monomers, which are dispersed in tissue-equivalent gelatin, has been shown to be dependent on the dose, but independent of the dose rate or photon energy. Therefore, the spatial distribution of polymer in the gel is precisely representative of the dose distribution. As the polymeric microparticles reduce the water proton NMR relaxation times in the gel, the dose distribution can be measured with high resolution and accuracy using magnetic resonance imaging. Also, as these microparticles cannot diffuse through the gelatin matrix, their distribution is permanent. An improved formulation of the BANG dosimeter consists of 3% w/v acrylic acid, 3% N,N'-methylene-bis-acrylamide, 1% sodium hydroxide, 5% gelatin, and 88% water. MR images are transferred via a local network to a Macintosh computer, and R2 maps constructed on the basis of multiple TE images, using a non-linear least squares fit based on the Levenberg-Marquardt algorithm. A dose-to-R2

  9. Hybrid Materials of Polymer Gels with Surfactants

    Institute of Scientific and Technical Information of China (English)

    Hu Yan; Kaoru Tsujii

    2005-01-01

    @@ 1 Introduction Polymer gels have been extensively studied[1~17] since the discovery of volume phase-transition of a gel by Tanaka[1~5]. As a unique soft material, gels attract much attention and are tried to be applied for drug-delivery systgems[6], actuators or chemo-mechanical devices[7~9] and so on. In particular, controlled-release of small molecules from a gel is now a subject of special interest[10].

  10. Coordination Polymer Gels by Electron Beam

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Ha; Cho, Young Je; Jung, Jong Hwa [Gyeongsang National Univ., Jinju (Korea, Republic of)

    2011-07-01

    Hydrogenation of a pyridine derivative possessing tetrazole moieties as end groups, without long alkyl chain groups, results in the formation of a Mg(NO{sub 3}){sub 2} coordination polymer gel. The polymer exhibits a strong fluorescence enhancement upon gel formation. 1 can also be gloated with a variety of magnesium anions such as SO{sub 4}{sup 2-}, NO{sub 3}{sup -}, Cl{sup -}, Br{sup -} and I{sup -}, indicating that the coordination polymer gel formation of 1 does not strongly depends on anions. The Seam and ABM images of Mg{sup 2+} coordination polymer gel 1 display a flabbier network with several micrometers long, widths in the range 60-70 nm and thicknesses of about 3 nm. In addition, photophysical studies show that the hydrogel exhibits a typical {pi}-{pi} transition and gives rise to high fluorescence behavior. The coordination polymer hydrogel exhibits viscoelastic behavior as evidenced from the rheological studies.

  11. Electrochemical Study of Conductive Gel Polymer

    Institute of Scientific and Technical Information of China (English)

    Zhaohui Li; Jing Jiang; Gangtie Lei

    2005-01-01

    @@ 1Introduction Conventional ion-conducting polymer consists of electrolyte salt and polymer matrix, so-called salt-inpolymer. It possesses lower conductivity because the migration of ions depends on the motion of polymer segmental. To increase the ionic conductivity, a kind of gel polymer film (GPF) was prepared by in situ polymerization of methyl methacrylate (MMA) monomer in room-temperature ionic liquid(RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIPF6). Due to immeasurably low vapor pressure, high ionic conductivity, and greater thermal and electrochemical stability, BMIPF6 is suitable electrolyte salts for ion-conducting polymer.

  12. Conducting polymer electrodes for gel electrophoresis.

    Directory of Open Access Journals (Sweden)

    Katarina Bengtsson

    Full Text Available In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that π-conjugated polymers such as poly(3,4-ethylenedioxythiophene (PEDOT can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis systems. In this report, we extend our previous result to gel electrophoresis, and show that electrodes containing PEDOT can be used with a commercial polyacrylamide gel electrophoresis system with minimal impact to the resulting gel image or the ionic transport measured during a separation.

  13. Dynamic Scaling of Polymer Gels Comprising Nanoparticles

    OpenAIRE

    Teixeira, Alvaro V. N. C.; Geissler, Erik; Licinio, Pedro

    2014-01-01

    We present dynamic light scattering (DLS) measurements of soft polymethyl-methacrylate (PMMA) and polyacrylamide(PA) polymer gels prepared with trapped bodies (latex spheres or maghemite nanoparticles). We show that the anomalous diffusivity of the trapped particles can be analyzed in terms of a fractal Gaussian network gel model for the entire time range probed by DLS technique. This model is a generalization of the Rouse model for linear chains extended for structures with power law network...

  14. Rheological properties of polymer micro-gel dispersions

    Institute of Scientific and Technical Information of China (English)

    Dong Zhaoxia; Li Yahua; Lin Meiqin; Li Mingyuan

    2009-01-01

    The influence of swelling time, temperature, NaCI concentration and polymer micro-gel concentration on rheological properties of polymer micro-gel dispersions was studied by using a HAAKE rheometer. The results showed that with increasing swelling time and NaCI concentration, the polymer micro-gel dispersions changed from a shear-thickening fluid to a Newtonian fluid. The polymer micro- gel dispersion show shear-thinning in non-saline water. At higher swelling temperature, the time of the polymer micro-gel dispersion showing shear-thickening was shorter. With increasing polymer micro-gel concentration, the dispersion changed from shear-thickening to shear-thinning.

  15. A comparative study of new type polymer gel dosimeters

    International Nuclear Information System (INIS)

    In this study we have investigated and evaluated some dosimetric properties of polymer gel dosimeter encountered when using gels in clinical radiation therapy environment. Four different compositions of polymer gel dosimeter were manufactured. Two compositions (A and D) represent widely recognized gels prepared following literature instructions. In case of MAGIC type dosimeter (D), gelatin weight fraction was decreased to 5%. During our previous research, we have experienced some substantial changes in behavior when lowering amount of sodium hydroxide and when potassium aluminum sulfate was added. Therefore another two gels were prepared (B and C). Gel dosimeters were evaluated using transversal relaxation rate R2. Details of the used acquisition sequence may be found in Spevacek V. et.al. (2001), only eight echo times were used for R2 calculation in this case. The following properties have been investigated for the four gel compositions: dose response; temperature dependence of dose response; short and long term stability; behavior of gels in a region of steep dose gradient; and uniformity of homogeneously irradiated region. (authors)

  16. Mechanical properties and morphology of polymer gels

    Science.gov (United States)

    Sliozberg, Yelena; Sirk, Timothy; Brennan, John; Andzelm, Jan; Mrozek, Randy; Lenhart, Joseph

    2012-02-01

    Understanding morphology and mechanical response of polymeric gels is of particular importance to design materials with required energy dissipation characteristics. We will present our latest results for polymer gels based on 1) self-assembled block copolymers and 2) chemically cross-linked polymers. The dissipative particle dynamics (DPD) was used to predict morphology in good agreement with atomic force microscopy. We have performed DPD non-equilibrium oscillatory shear calculations predicting elastic modulus of unentangled gels that correlates well with experimental rheology data. However, this methodology fails to predict mechanics of entangled polymer networks due to unphysical chain crossing brought by the soft potentials used in DPD simulations. Recently, we have introduced an improved segmental repulsion potential that removes the bond crossing allowing for reptation dynamics. The improved DPD method was used in simulations for entangled gels to explore impact of branched architecture of solvent on the mechanical response to the tensile deformation. Novel architectures of solvent resulting in a dramatic increase of the elastic modulus were identified. The topological analysis was applied to understand contributions of chemical cross-links and entanglements to the stress.

  17. Optical-CT scanning of polymer gels

    International Nuclear Information System (INIS)

    The application of optical-CT scanning to achieve accurate high-resolution 3D dosimetry is a subject of current interest. The purpose of this paper is to provide a brief overview of past research and achievements in optical-CT polymer gel dosimetry, and to review current issues and challenges. The origins of optical-CT imaging of light-scattering polymer gels are reviewed. Techniques to characterize and optimize optical-CT performance are presented. Particular attention is given to studies of artifacts in optical-CT imaging, an important area that has not been well studied to date. The technique of optical-CT simulation by Monte-Carlo modeling is introduced as a tool to explore such artifacts. New simulation studies are presented and compared with experimental data

  18. Carbon Redox-Polymer-Gel Hybrid Supercapacitors

    Science.gov (United States)

    Vlad, A.; Singh, N.; Melinte, S.; Gohy, J.-F.; Ajayan, P. M.

    2016-02-01

    Energy storage devices that provide high specific power without compromising on specific energy are highly desirable for many electric-powered applications. Here, we demonstrate that polymer organic radical gel materials support fast bulk-redox charge storage, commensurate to surface double layer ion exchange at carbon electrodes. When integrated with a carbon-based electrical double layer capacitor, nearly ideal electrode properties such as high electrical and ionic conductivity, fast bulk redox and surface charge storage as well as excellent cycling stability are attained. Such hybrid carbon redox-polymer-gel electrodes support unprecedented discharge rate of 1,000C with 50% of the nominal capacity delivered in less than 2 seconds. Devices made with such electrodes hold the potential for battery-scale energy storage while attaining supercapacitor-like power performances.

  19. SURFACE DYNAMIC FRICTION OF POLYMER GELS

    Institute of Scientific and Technical Information of China (English)

    J.P.Gong; G.Kagata; Y.Iwasaki; Y.Osada

    2000-01-01

    The sliding friction of various kinds of hydrogels has been studied and it was found that the frictional behaviors of the hydrogels do not conform to Amonton's law F =μW which well describes the friction of solids. The frictional force and its dependence on the load are quite different depending on the chemical structures of the gels, surface properties of the opposing substrates, and the measurement condition. The gel friction is explained in terms of interfacial interaction, either attractive or repulsive, between the polymer chain and the solid surface. According to this model, the friction is ascribed to the viscous flow of solvent at the interface in the repulsive case. In the attractive case, the force to detach the adsorbing chain from the substrate appears as friction. The surface adhesion between glass particles and gels measured by AFM showed a good correlation with the friction, which supported the repulsion-adsorption model proposed by the authors.

  20. Polymer and Polymer Gel of Liquid Crystalline Semiconductors

    Institute of Scientific and Technical Information of China (English)

    Teppei Shimakawa; Naoki Yoshimoto; Jun-ichi Hanna

    2004-01-01

    It prepared a polymer and polymer gel of a liquid crystalline (LC) semiconductor having a 2-phenylnaphthalene moiety and studied their charge carrier transport properties by the time-of-flight technique. It is found that polyacrylate having the mesogenic core moiety of 2-phenylnaphtalene (PNP-acrylate) exhibited a comparable mobility of 10-4cm2/Vs in smectic A phase to those in smectic A (SmA) phase of small molecular liquid crystals with the same core moiety, e.g., 6-(4'-octylphenyl)- 2-dodecyloxynaphthalene (8-PNP-O12), and an enhanced mobility up to 10-3cm2/Vs in the LC-glassy phase at room temperature, when mixed with a small amount of 8-PNP-O12. On the other hand, the polymer gel consisting of 20 wt %-hexamethylenediacrylate (HDA)-based cross-linked polymer and 8-PNP-O12 exhibited no degraded mobility when cross-linked at the mesophase. These results indicate that the polymer and polymer composite of liquid crystalline semiconductors provide us with an easy way to realize a quality organic semiconductor thin film for the immediate device applications.

  1. Soluble polymers in sol-gel silica

    Science.gov (United States)

    Beaudry, Christopher Laurent

    In the last few years, the inherent versatility of sol-gel processing has led to a significant research effort on inorganic/organic materials. One method of incorporating an organic phase into sol-gel silica is dissolving an organic polymer in a tetraethylorthosilicate (TEOS) solution, followed by in situ polymerization of silica in the presence of organic polymer. The first part of the study involved the development of a two-step (acid-base) synthesis procedure to allow systematic control of acidity in TEOS solutions. With this procedure, it was possible to increase the pH of the TEOS solution while correlating the acidity and properties. The properties were the gelation time, syneresis rate, drying behavior, and xerogel pore structure, as determined by nitrogen sorption. Furthermore, controlling the acidity was shown to control the silica xerogel pore structure. In the second part of the study, the two-step procedure was used to synthesize silica/poly(ethylene glycol) (PEG), and silica/poly(vinyl acetate) (PVAc) composite materials. The content of organic polymer and the molecular weight were varied. The gelation time, the syneresis rate, the drying behavior, and the pore structure were determined for compositions with 10% PEG (M.W. 2,000), 5, 10, and 15% PEG (M.W. 3,400), and 10 and 25% PVAc (M.W. 83,000). Other compositions and molecular weights of PEG lead to sedimentation. In the PEG compositions, the tendency to phase separate was correlated with the effects of the processing variables on the segregation strength and polymerization rate. The PVAc compositions did not show any visible phase separation during processing, giving the composite xerogels an appearance similar to pure silica. The property differences between gels with PEG and gels with PVAc show the relative strength of the interactions with silica. Both polymers exhibit hydrogen bonding between the phases. In the case of PEG, hydrogen bonding between the ether oxygens of the polymer and silanol

  2. Antioxidant effect of green tea on polymer gel dosimeter

    International Nuclear Information System (INIS)

    Extract from Green Tea (GTE) acts as an antioxidant in acrylamide based polymer gel dosimeter. In this work, PAGAT gel was used for investigation of antioxidant effect of GTE.PAGAT was called PAGTEG (Polyacrylamide green tea extract gel dosimeter) after adding GTE. Free radicals in water cause pre polymerization of polymer gel before irradiation. Polyphenols from GTE are highly effective to absorb the free radicals in water. THPC is used as an antioxidant in polymer gel dosimeter but here we were replaced it by GTE and investigated its effect by spectrophotometer. GTE added PAGAT samples response was lower compared to THPC added sample. To increase the sensitivity of the PAGTEG, sugar was added. This study confirmed that THPC was a good antioxidant for polymer gel dosimeter. However, GTE also can be used as an antioxidant in polymer gel if use less quantity (GTE) and add sugar as sensitivity enhancer

  3. Antioxidant effect of green tea on polymer gel dosimeter

    Science.gov (United States)

    Samuel, E. J. J.; Sathiyaraj, P.; Deena, T.; Kumar, D. S.

    2015-01-01

    Extract from Green Tea (GTE) acts as an antioxidant in acrylamide based polymer gel dosimeter. In this work, PAGAT gel was used for investigation of antioxidant effect of GTE.PAGAT was called PAGTEG (Polyacrylamide green tea extract gel dosimeter) after adding GTE. Free radicals in water cause pre polymerization of polymer gel before irradiation. Polyphenols from GTE are highly effective to absorb the free radicals in water. THPC is used as an antioxidant in polymer gel dosimeter but here we were replaced it by GTE and investigated its effect by spectrophotometer. GTE added PAGAT samples response was lower compared to THPC added sample. To increase the sensitivity of the PAGTEG, sugar was added. This study confirmed that THPC was a good antioxidant for polymer gel dosimeter. However, GTE also can be used as an antioxidant in polymer gel if use less quantity (GTE) and add sugar as sensitivity enhancer.

  4. CURRENT COLLOIDAL DISPERSION GELS ARE NOT SUPERIOR TO POLYMER FLOODING

    Institute of Scientific and Technical Information of China (English)

    Seright Randy; Han Peihui; Wang Dongmei

    2006-01-01

    The suggestion that the colloidal-dispersion-gel (CDG) process is superior to normal polymer flooding is misleading and generally incorrect. Colloidal dispersion gels, in their present state of technological development, should not be advocated as an improvement to, or substitute for, polymer flooding. Gels made from aluminum-citrate crosslinked polyacrylamides can act as conventional gels and provide effective conformance improvement in treating some types of excess water production problems if sound scientific and engineering principles are respected.

  5. Investigating potential physicochemical errors in polymer gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Sedaghat, Mahbod; Lepage, Martin [Centre d' imagerie moleculaire de Sherbrooke, Departement de medecine nucleaire et radiobiologie, Universite de Sherbrooke, Sherbrooke, QC (Canada); Bujold, Rachel, E-mail: martin.lepage@usherbrooke.ca [Service de radio-oncologie, Centre hospitalier universitaire de Sherbrooke, Sherbrooke, QC (Canada)

    2011-09-21

    Measurement errors in polymer gel dosimetry can originate either during irradiation or scanning. One concern related to the exothermic nature of polymerization reaction was that the heat released in polymer gel dosimeters during irradiation modifies their dose response. In this paper, the effect of heat released from the exothermal polymerization reaction on the dose response of a number of dosimeters was studied. In addition, we investigated whether heat-generated geometric distortion existed in newly proposed gel dosimeters that contain highly thermoresponsive polymers. Our results suggest that despite a significant internal temperature increase in some gel compositions, their dose responses are not affected when oxygen is well expelled mechanically from the gel mixture. We also report on significant pre-irradiation instability in some recently developed polymer gel dosimeters but that geometric distortions were not observed. Data obtained by a set of small calibration vials are compared to those obtained from larger phantoms, and potential physicochemical causes of deviations between them are identified.

  6. How to scan polymer gels with MRI?

    Science.gov (United States)

    De Deene, Y.

    2013-06-01

    The absorbed radiation dose fixated in a polymer gel dosimeter can be read out by several methods such as magnetic resonance imaging (MRI), optical CT, X-ray CT and ultrasound with MRI being the first method that was explored. Although MRI was considered as an elegant scanning technique, readily available in most hospitals, it was later found that using a non-optimized imaging protocol may result in unacceptable deviations in the obtained dose distribution. Although most medical physicists have an understanding of the basic principles of magnetic resonance imaging (MRI), the optimization of quantitative imaging sequences and protocols is often perceived as the work of MRI experts. In this paper, we aim at providing the reader with some easy guidelines in how to obtain reliable quantitative MRI maps.

  7. Drying and shrinkage of polymer gels

    Directory of Open Access Journals (Sweden)

    S. S. Waje

    2005-06-01

    Full Text Available The polymer hydrogel was synthesized by photo-polymerization process (UV light, 60 ºC in presence of Photo-initiator (IrgacureR and Cross-linker (NN'-methylene bisacrylamide; MBAM. In the present work, the drying of polymer hydrogel was carried out to study the effect of temperature, gel-sheet thickness, monomer ratio of acryl acid to acrylamide (AA/AM, concentration of MBAM and quantity of monomers. A correlation has been developed for modified sheet thickness as a function of contraction coefficient and degree of drying. Effective diffusivity was estimated from Fickian-diffusive model considering modified sheet thickness and was found to be in the range of 1.1 ´ 10-10-5.93 ´ 10-10 m²/s. The activation energy obtained using Arrhenius type equation was found to be in the range of 2979-10737 kJ/kmol H2O. The drying behavior shows an initial shoot-up in drying rate followed by constant rate and two falling rate periods.

  8. Stabilization of polymer gels against divalent ion-induced syneresis

    Energy Technology Data Exchange (ETDEWEB)

    Albonico, Paola; Lockhart, Thomas P. [Eniricerche SpA, San Donato, Milan (Italy)

    1997-07-15

    Polymer solutions and polymer gels are unstable to extended ageing in divalent cation-rich brines at elevated temperature. This paper shows that low-molecular-weight compounds that complex strongly with Ca{sup 2+} and Mg{sup 2+} are capable of neutralizing their destabilizing influence on polymer solubility and of inhibiting the syneresis of crosslinked acrylamide polymer gels in hard brines. The solubility of the inhibitor-divalent ion complexes formed in hard brine at elevated temperature have also been examined. The results obtained offer the possibility to extend significantly the upper temperature limit for the use of polyacrylamides and acrylamide copolymers in brines in both polymer flooding and polymer gel treatments

  9. Preparation and clinical application of indomethacin gel for medical treatment of stomatitis.

    Science.gov (United States)

    Momo, Kenji; Shiratsuchi, Tatsuko; Taguchi, Hiroyuki; Hashizaki, Kaname; Saito, Yoshihiro; Makimura, Mizue; Ogawa, Naotake

    2005-05-01

    The preparation and clinical applications of indomethacin (IM) gel were investigated in the treatment of stomatitis resulting from chemotherapy and radiotherapy for cancer. IM gel was prepared by adding various water-soluble polymers [hydroxypropyl cellulose (HPC), etc.] to IM aqueous solution. The release rate of IM from IM gels was found to decrease with increasing polymer concentration and viscosity and to follow a first-order reaction rate equation. The release rate of IM from the IM gel with HPC was decreased gradually with increasing polymer concentration and to be easily controllable compared with gels with other polymers. The time before pain relief occurred after application of the IM gel was slightly shorter and the duration of pain relief was longer compared with the IM aqueous solution. It was confirmed that IM gel is useful in the treatment of stomatitis.

  10. Morphology of Polyvinylidene Fluoride Based Gel Polymer Electrolytes

    Institute of Scientific and Technical Information of China (English)

    田立颖; 黄小彬; 唐小真

    2004-01-01

    Two series of polyvinylidene fluoride (PVDF) based gel polymer electrolytes, with different LiClO4 or propylene carbonate (PC) content, were prepared and analyzed by infrared spectrometer, differential scanning calorimetry, scanning electron microscope and complex impedance spectrometer. The results show that there are great interactions between PVDF, PC and lithium cations. Both LiClO4 and PC content lead to evident change of the morphology of the gel polymer electrolytes. The content of LiClO4 and PC also influences the ionic conductivity of the samples,and an ionic conductivity of above 10-3S·cm-1 can be reached at room temperature.

  11. PMMA-based Gel Polymer Electrolytes with Crosslinking Network

    Institute of Scientific and Technical Information of China (English)

    H.P. Zhang; Y. P. Wu; H. Q. Wu; M. Sun

    2005-01-01

    @@ 1Introduction The lithium-ion battery has a good rate capability and low-temperature performance, but its safety is relatively low due to the possibility of leakage of liquid electrolyte. The use of a solid or gel type electrolyte can lower the probability of leakage liquid electrolyte, and the electrochemical performance of gel electrolyte doesn't decrease so markedly as the solid electrolyte. Now, new types of advanced lithium-ion battery with gel polymer electrolytes are under developing which can be used in the future.

  12. Nonlinear dynamics of self-oscillating polymer gels

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Self-oscillating polymer gels driven by Belousov-Zhabotinsky (BZ) chemical reaction are a new class of functional gels that have a wide range of potential applications (e.g., autonomously functioning membranes, actuate artificial muscles). However, the precise control of these gels has been an issue due to limited investigations of the influences of key system parameters on the characteristics of BZ gels. To address this deficiency, we studied the self-oscillating behavior of BZ gels using the nonline-ar dynamics theory and an Oregonator-like model, with focus placed upon the influences of various system parameters. The analysis of the oscillation phase indicated that the dynamic response of BZ gels represents the classical limit cycle oscillation. We then investigated the characteristics of the limit cycle oscillation and quantified the influences of key parameters (i.e., ini-tial reactant concentration, oxidation and reduction rate of catalyst, and response coefficient) on the self-oscillating behavior of BZ gels. The results demonstrated that sustained limit cycle oscillation of BZ gels can be achieved only when these key pa-rameters meet certain requirements, and that the pattern, period and amplitude of the oscillation are significantly influenced by these parameters. The results obtained in this study could enable the controlled self-oscillation of BZ gels system. This has several potential applications such as controlled drug delivery, miniature peristaltic pumps and microactuators.

  13. Dosimetric evaluation of a novel polymer gel dosimeter for proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Zeidan, O. A.; Sriprisan, S. I.; Lopatiuk-Tirpak, O.; Kupelian, P. A.; Meeks, S. L.; Hsi, W. C.; Li, Z.; Palta, J. R.; Maryanski, M. J. [M. D. Anderson Cancer Center Orlando, Orlando, Florida 32806 (United States); University of Florida Proton Therapy Institute, Jacksonville, Florida 32206 (United States); MGS Research, Inc., Madison, Connecticut 06443 (United States)

    2010-05-15

    Purpose: The aim of this study is to evaluate the dosimetric performance of a newly developed proton-sensitive polymer gel formulation for proton therapy dosimetry. Methods: Using passive scattered modulated and nonmodulated proton beams, the dose response of the gel was assessed. A next-generation optical CT scanner is used as the readout mechanism of the radiation-induced absorbance in the gel medium. Comparison of relative dose profiles in the gel to ion chamber profiles in water is performed. A simple and easily reproducible calibration protocol is established for routine gel batch calibrations. Relative stopping power ratio measurement of the gel medium was performed to ensure accurate water-equivalent depth dose scaling. Measured dose distributions in the gel were compared to treatment planning system for benchmark irradiations and quality of agreement is assessed using clinically relevant gamma index criteria. Results: The dosimetric response of the gel was mapped up to 600 cGy using an electron-based calibration technique. Excellent dosimetric agreement is observed between ion chamber data and gel. The most notable result of this work is the fact that this gel has no observed dose quenching in the Bragg peak region. Quantitative dose distribution comparisons to treatment planning system calculations show that most (>97%) of the gel dose maps pass the 3%/3 mm gamma criterion. Conclusions: This study shows that the new proton-sensitive gel dosimeter is capable of reproducing ion chamber dose data for modulated and nonmodulated Bragg peak beams with different clinical beam energies. The findings suggest that the gel dosimeter can be used as QA tool for millimeter range verification of proton beam deliveries in the dosimeter medium.

  14. Carbon beam dosimetry using VIP polymer gel and MRI

    DEFF Research Database (Denmark)

    Kantemiris, I; Petrokokkinos, L; Angelopoulos, A;

    2009-01-01

    VIP polymer gel dosimeter was used for Carbon ion beam dosimetry using a 150 MeV/n beam with 10 Gy plateau dose and a SOBP irradiation scheme with 5 Gy Bragg peak dose. The results show a decrease by 8 mm in the expected from Monte Carlo simulation range in water, suggesting that the dosimeter...

  15. Rheology and Relaxation Timescales of ABA Triblock Polymer Gels

    Science.gov (United States)

    Peters, Andrew; Lodge, Timothy

    When dissolved in a midblock selective solvent, ABA polymers form gels composed of aggregated end block micelles bridged by the midblocks. While much effort has been devoted to the study of the structure of these systems, the dynamics of these systems has received less attention. We examine the underlying mechanism of shear relaxation of ABA triblock polymer gels, especially as a function of chain length, composition, and concentration. Recent work using time-resolved small-angle neutron scattering of polystyrene (PS)-block-poly(ethylene-alt-propylene) (PEP) in squalane has elucidated many aspects of the dynamics of diblock chain exchange. By using rheology to study bulk relaxation phenomena of the triblock equivalent, PS-PEP-PS, we apply the knowledge gained from the chain exchange studies to bridge the gap between the molecular and macroscopic relaxation phenomena in PS-PEP-PS triblock gels.

  16. NMR study of starch based polymer gel electrolytes: Humidity effects

    International Nuclear Information System (INIS)

    In this work, nuclear magnetic resonance spectroscopy (NMR) was used to study the effect of water absorption in polymer gel electrolytes formed by amylopectin rich starch, plasticized with glycerol and containing lithium perchlorate. The position of the 7Li spin-lattice relaxation rate maximum is shifted progressively towards lower temperatures with increasing hydration, reflecting an increase of the lithium mobility. The mechanism responsible for the spin-lattice relaxation of the 7Li nuclei in the gel electrolytes are the fluctuations of the quadrupolar interaction due to the lithium motions. The 7Li relaxation results of the gel electrolyte hydrated with 2.2 water per complex unit suggest that the lithium ions are almost decoupled from the polymer chain and coordinate, hence preferring the water molecules

  17. Feasibility of quantitative PET/CT dosimetry for proton therapy using polymer gels

    Energy Technology Data Exchange (ETDEWEB)

    Zeidan, O A; Hsi, W C; Lopatiuk-Tirpak, O; Sriprisan, S I; Meeks, S L; Kupelian, P A; Li, Z; Palta, J R, E-mail: lenatirpak@gmail.co

    2010-11-01

    A feasibility study of proton beam PET/CT off-line quantitative dosimetry using polymer gels is presented. A newly developed proton-sensitive polymer gel dosimeter (BANG( (registered)) 3-Pro2) is used as a dosimeter and a tissue-equivalent phantom medium for this study. We explore a new approach to correlating measured proton 3-dimensional (3D) dose distributions directly to measured positron emission from in the gel medium using PET/CT imaging. A large cylindrical volume (2.2 Litres) of the gel was irradiated with a clinical modulated proton beam using irregular-shaped aperture geometry. The gel was imaged in a nearby PET/CT unit immediately (<3 min) after irradiation. Dose distribution in the gel was generated using an optical tomography scanning system. Direct 3D spatial comparison of dose and positron emission distributions was then performed. Profiles along the beam path show that the distal fall-off of the dose is nearly 2 cm deeper than the activity profile which is comparable to previous studies with plastic phantoms and Monte Carlo simulations of activity distributions. Planar PET and dose distributions at depth and perpendicular to beam axis show a strong one-to-one spatial correlation. This phantom study demonstrates that the gel medium could be potentially useful for quantifying various physical factors that can influence the PET activity range verification method in patients.

  18. All-solid-state proton battery using gel polymer electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Kuldeep, E-mail: mishkuldeep@gmail.com [Department of Applied Science and Humanities, ABES Engineering College, Ghaziabad-201009, India and Department of Physics and Materials Science and Engineering, Jaypee Institute of Information Technology, Noida-201307 (India); Pundir, S. S.; Rai, D. K. [Department of Physics and Materials Science and Engineering, Jaypee Institute of Information Technology, Noida-201307 (India)

    2014-04-24

    A proton conducting gel polymer electrolyte system; PMMA+NH{sub 4}SCN+EC/PC, has been prepared. The highest ionic conductivity obtained from the system is 2.5 × 10−4 S cm{sup −1}. The optimized composition of the gel electrolyte has been used to fabricate a proton battery with Zn/ZnSO{sub 4}⋅7H{sub 2}O anode and MnO{sub 2} cathode. The open circuit voltage of the battery is 1.4 V and the highest energy density is 5.7 W h kg−1 for low current drain.

  19. Investigation on poly (vinylidene fluoride) based gel polymer electrolytes

    Indian Academy of Sciences (India)

    S Rajendran; P Sivakumar; Ravi Shanker Babu

    2006-12-01

    An investigation is carried out on gel polymer electrolytes consisting of poly (vinylidene fluoride) (PVdF) as a host polymer, lithium perchlorate (LiClO4), lithium triflate (LiCF3SO3) as salts and mixture of ethylene carbonate (EC) and propylene carbonate (PC) as plasticizers. Polymer thin films were prepared by solvent casting technique and the obtained films were subjected to different characterizations, to confirm their structure, complexation and thermal changes. X-ray diffraction revealed that the salts and plasticizers disrupted the crystalline nature of PVdF based polymer electrolytes and converted them into an amorphous phase. TG/DTA studies showed the thermal stability of the polymer electrolytes. The role of interaction between polymer hosts on conductivity is discussed using the results of a.c. impedance studies. Room temperature (28°C) conductivity of 2.786 × 10-3 Scm-1 was observed in PVdF (24)–EC/PC (68)–LiCF3SO3 (2)/LiClO4 (6) polymer system.

  20. The fundamental radiation properties of normoxic polymer gel dosimeters: a comparison between a methacrylic acid based gel and acrylamide based gels

    International Nuclear Information System (INIS)

    Polymer gel dosimeters offer a wide range of applications in the three-dimensional verification of complex dose distributions such as in intensity-modulated radiotherapy. One of the major difficulties with polymer gel dosimeters is their sensitivity to oxygen, as oxygen inhibits the radiation-induced polymerization reaction. For several years, oxygen was removed from the gels by bubbling the sol with inert gases for several hours during the gel fabrication. Also, the gel had to be poured in containers with low oxygen permeability and solubility. Recently, it was found that these technical difficulties can easily be solved by adding an antioxidant to the gel. These gels are called 'normoxic' gels as they can be produced under normal atmospheric conditions. In this study several properties of polymer gel dosimeters have been investigated: the dose sensitivity, the temporal and spatial stability of the gel, the sensitivity of the dose response to temperature during irradiation and during MR imaging, the energy dependence and the dose-rate dependence. This study reveals that the normoxic polymer gel dosimeter based on methacrylic acid (nMAG) studied in this work has inferior radiation properties as compared to the polyacrylamide gelatine (PAG) gel dosimeters. It is shown that from the three different gel dosimeters investigated in this study, the nPAG gel dosimeter results in a less sensitive gel dosimeter but with superior radiation properties as compared to the nMAG gel dosimeter. The importance of investigating relevant radiation properties of gel dosimeters apart from the radiation sensitivity-prior to their use for dosimetric validation experiments-is illustrated and emphasized throughout this study. Other combinations of monomer and gelling agent may result in more reliable normoxic polymer gel dosimeters

  1. Surface structure of polymer Gels and emerging functions

    CERN Document Server

    Kobiki, Y

    1999-01-01

    We report the surface structure of polymer gels on a submicrometer scale during the volume phase transition. Sponge-like domains with a mesoscopic scale were directly observed in water by using at atomic force microscope (AFM). The surface structure characterized by the domains is discussed in terms of the root-mean-square roughness and the auto-correlation function, which were calculated from the AFM images. In order to demonstrate the role of surface structure in determining the macroscopic properties of film-like poly (N-isopropylacrylamide: NIPA) gels. It was found that the temperature dependence, as well as the absolute values of the static contact angle, were strongly dependent on the bulk network inhomogeneities. The relation between the mesoscopic structure and the macroscopic properties is qualitatively discussed in terms of not only the changes in the chemical, but also in the physical, surface properties of the NIPA gels in response to a temperature change.

  2. Polymer sol-gel composite inverse opal structures.

    Science.gov (United States)

    Zhang, Xiaoran; Blanchard, G J

    2015-03-25

    We report on the formation of composite inverse opal structures where the matrix used to form the inverse opal contains both silica, formed using sol-gel chemistry, and poly(ethylene glycol), PEG. We find that the morphology of the inverse opal structure depends on both the amount of PEG incorporated into the matrix and its molecular weight. The extent of organization in the inverse opal structure, which is characterized by scanning electron microscopy and optical reflectance data, is mediated by the chemical bonding interactions between the silica and PEG constituents in the hybrid matrix. Both polymer chain terminus Si-O-C bonding and hydrogen bonding between the polymer backbone oxygens and silanol functionalities can contribute, with the polymer mediating the extent to which Si-O-Si bonds can form within the silica regions of the matrix due to hydrogen-bonding interactions.

  3. Uptake and Recovery of Lead by Agarose Gel Polymers

    Directory of Open Access Journals (Sweden)

    Anurag Pandey

    2009-01-01

    Full Text Available Problem statement: The uptake and recovery of lead ions were investigated by using agarose gel polymers. Approach: The experimental results showed that the agarose gel were effective in removing Pb (II from solution. Biosorption equilibrium was approached within 4 h. Pseudo second-order was applicable to all the sorption data over the entire time range. Results: The sorption data conformed well to both the Langmuir and the Freundlich isotherm model. The maximum adsorption capacity (qmax onto agarose gel was 115 mg g-1 for Pb (II. The maximum uptake of metal ions was obtained at pH 2.0. At temperature 35°C, the biosorption of metal ions was found to be highest, with increase or decrease in temperature resulted in a decrease in the metal ions uptake capacity. Conclusion: Elution experiments were carried out to remove Pb (II ions from loaded agarose gel and the bound metal ions could be eluted successfully using 0.1 M EDTA solution. The results suggest that agarose gel can be used as a biosorbent for an efficient removal of Pb(II ions from aqueous solution.

  4. Gelation Behavior of Poly (Vinylidene Fluoride )-based Gel Polymer Electrolyte

    Institute of Scientific and Technical Information of China (English)

    WANG Biao-bing; GU Li-xia

    2006-01-01

    Poly ( vinylidene fluoride ) ( PVdF )-based gel polymer electrolytes with various compositions were prepared by solution casting technique. The kinetics of gelation was analyzed via the correlation between the apparent gelation rate and concentration of PVdF at a given temperature.Combination the results of the kinetics of gelation and the DSC study, it revealed that the phase separation was the major behavior and the fibrils were the major junction joints of the three-dimensional network even in the ease the concentration of PVdF was higher than 25 wt%. The porous surface observed by ESEM also reflected that the phase separation took place during the gelation.

  5. Formulation Development and Evaluation of Innovative Two-Polymer (SR-2P) Bioadhesive Vaginal Gel

    OpenAIRE

    Podaralla, Satheesh; Alt, Carsten; Shankar, Gita N.

    2014-01-01

    The main objective of this investigation was to study the feasibility of developing a vaginal bioadhesive microbicide using a SRI’s proprietary two-polymer gel platform (SR-2P). Several formulations were prepared with different combinations of temperature-sensitive polymer (Pluronic® F-127) and mucoadhesive polymer (Noveon® AA-1), producing gels of different characteristics. Prototype polymeric gels were evaluated for pH, osmolality, buffering capacity, and viscosity under simulated vaginal s...

  6. Energy dependence of polymer gels in the orthovoltage energy range

    Directory of Open Access Journals (Sweden)

    Yvonne Roed

    2014-03-01

    Full Text Available Purpose: Ortho-voltage energies are often used for treatment of patients’ superficial lesions, and also for small- animal irradiations. Polymer-Gel dosimeters such as MAGAT (Methacrylic acid Gel and THPC are finding increasing use for 3-dimensional verification of radiation doses in a given treatment geometry. For mega-voltage beams, energy dependence of MAGAT has been quoted as nearly energy-independent. In the kilo-voltage range, there is hardly any literature to shade light on its energy dependence.Methods: MAGAT was used to measure depth-dose for 250 kVp beam. Comparison with ion-chamber data showed a discrepancy increasing significantly with depth. An over-response as much as 25% was observed at a depth of 6 cm.Results and Conclusion: Investigation concluded that 6 cm water in the beam resulted in a half-value-layer (HVL change from 1.05 to 1.32 mm Cu. This amounts to an effective-energy change from 81.3 to 89.5 keV. Response measurements of MAGAT at these two energies explained the observed discrepancy in depth-dose measurements. Dose-calibration curves of MAGAT for (i 250 kVp beam, and (ii 250 kVp beam through 6 cm of water column are presented showing significant energy dependence.-------------------Cite this article as: Roed Y, Tailor R, Pinksy L, Ibbott G. Energy dependence of polymer gels in the orthovoltage energy range. Int J Cancer Ther Oncol 2014; 2(2:020232. DOI: 10.14319/ijcto.0202.32 

  7. Responsive Gels with the Polymer Containing Alternating Naphthalene Diimide and Fluorinated Alkyl Chains: Gel Formation and Responsiveness as Well as Electrical Conductivity of Polymer Thin Films

    Institute of Scientific and Technical Information of China (English)

    罗河伟; 刘子桐; 蔡政旭; 吴刘锁; 张关心; 刘琛阳; 张德清

    2012-01-01

    A new electroactive polymer 1 with alternating NDI (naphthalene diimide) moieties and fluorinated alkyl chains was prepared and characterized. Gels of polymer 1 were formed in several solvents. Interestingly, gels of polymer 1 exhibited responsiveness toward N2H4, F and CN . Absorption and ESR spectroscopic studies revealed that such responsiveness is owing to the reduction of NDI moieties into the respective NDI'-. In addition, thin films of polymer 1 were easily prepared with spin-coating technique and the electrical conductivity of thin films reached 52.4 S/m after exposure to NeH4 vapor.

  8. Availability of a containerless polymer gel detector and a gelatin container

    International Nuclear Information System (INIS)

    We considered an availability of the polymer gel detector without container but with a plastic wrap under assumption of the low oxygen transmissivity of a sheet of plastic wrap. And a gelatin container was also examined for a gel detector. These samples can be made easily and this containerless polymer gel detector well works without any artifacts by means of wrapping with a thin plastic sheet. Nevertheless, there is still room for improvement on preventing oxygen contamination. Combination with a gelatin container and a polymer gel detector and/or Gafchromic films has a various potential for extension of 3D dosimetry

  9. Biodegradable polymers in clinical use and clinical development

    CERN Document Server

    Domb, Abraham J

    2011-01-01

    The definitive guide to biodegradable polymer science-where we are and what's to come The most comprehensive review of biodegradable polymers already utilized or under development for clinical use, Biodegradable Polymers in Clinical Use and Clinical Development looks at the state of biodegradable polymers now and over the next five years. Implantable molecules that break down within the body over a predetermined period of time, biodegradable polymers have been employed as drug carriers, orthopedic fixation devices, and absorbable sutures. Yet while hundreds of such polymers have been deve

  10. Characterization of dose-dependent Young's modulus for a radiation-sensitive polymer gel

    International Nuclear Information System (INIS)

    Radiation-sensitive polymer gels for clinical dosimetry have been intensively investigated with magnetic resonance imaging (MRI) because the transversal magnetic relaxation time is dependent on irradiation dose. MRI is expensive and not easily available in most clinics. For this reason, low-cost, quick and easy-to-use potential alternatives such as optical computed tomography (CT), x-ray CT or ultrasound attenuation CT have also been studied by others. Here, we instead evaluate the dose dependence of the elastic material property, Young's modulus and the dose response of the viscous relaxation of radiation-sensitive gels to discuss their potential for dose imaging. Three batches of a radiation-sensitive polymer gel (MAGIC gel) samples were homogeneously irradiated to doses from 0 Gy to 45.5 Gy. Young's modulus was computed from the measured stress on the sample surface and the strain applied to the sample when compressing it axially, and the viscous relaxation was determined from the stress decay under sustained compression. The viscous relaxation was found not to change significantly with dose. However, Young's modulus was dose dependent; it approximately doubled in the gels between 0 Gy and 20 Gy. By fitting a second-order polynomial to the Young's modulus-versus-dose data, 99.4% of the variance in Young's modulus was shown to be associated with the change in dose. The precision of the gel production, irradiation and Young's modulus measurement combined was found to be 4% at 2 Gy and 3% at 20 Gy. Potential sources of measurement error, such as those associated with the boundary conditions in the compression measurement, inhomogeneous polymerization, temperature (up to 1% error) and the evaporation of water from the sample (up to 1% error), were estimated and discussed. It was concluded that Young's modulus could be used for dose determination. Imaging techniques such as elastography may help to achieve this if they can provide a local measurement of Young

  11. Polymer gels with associating side chains and their interaction with surfactants

    Science.gov (United States)

    Gordievskaya, Yulia D.; Rumyantsev, Artem M.; Kramarenko, Elena Yu.

    2016-05-01

    Conformational behaviour of hydrophobically modified (HM) polymer gels in solutions of nonionic surfactants is studied theoretically. A HM gel contains hydrophobic side chains (stickers) grafted to its subchains. Hydrophobic stickers are capable to aggregate into joint micelles with surfactant molecules. Micelles containing more than one sticker serve as additional physical cross-links of the network, and their formation causes gel shrinking. In the proposed theoretical model, the interior of the gel/surfactant complex is treated as an array of densely packed spherical polymer brushes consisting of gel subchains tethered to the surface of the spherical sticker/surfactant micelles. Effect of stickers length and grafting density, surfactant concentration and hydrophobicity on gel swelling as well as on hydrophobic association inside it is analyzed. It is shown that increasing surfactant concentration can result in a gel collapse, which is caused by surfactant-induced hydrophobic aggregation of stickers, and a successive gel reswelling. The latter should be attributed to a growing fraction of surfactants in joint aggregates and, hence, increasing number of micelles containing only one sticker and not participating in gel physical cross-linking. In polyelectrolyte (PE) gels hydrophobic aggregation is opposed by osmotic pressure of mobile counterions, so that at some critical ionization degree hydrophobic association is completely suppressed. Hydrophobic modification of polymers is shown to open new ways for controlling gel responsiveness. In particular, it is discussed that incorporation of photosensitive groups into gel subchains and/or surfactant tail could give a possibility to vary the gel volume by light. Since hydrophobic aggregation regularities in gels and solutions are common, we hope our findings will be useful for design of polymer based self-healing materials as well.

  12. Multiple-phase behavior and memory effect of polymer gel

    CERN Document Server

    Annaka, M; Nakahira, T; Sugiyama, M; Hara, K; Matsuura, T

    2002-01-01

    A poly(4-acrylamidosalicylic acid) gel (PASA gel) exhibits multiple phases as characterized by distinct degrees of swelling; the gel can take one of four different swelling values, but none of the intermediate values. The gel has remarkable memory: the phase behavior of the gel depends on whether the gel has experienced the most swollen phase or the most collapsed phase in the immediate past. The information is stored and reversibly erased in the form of a macroscopic phase transition behavior. The structure factors corresponding to these four phases were obtained by SANS, which indicated the presence of characteristic structures depending on pH and temperature, particularly in the shrunken state. (orig.)

  13. Crosslinked polymer gel electrolytes based on polyethylene glycol methacrylate and ionic liquid for lithium battery applications

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Chen [ORNL; Sun, Xiao-Guang [ORNL; Dai, Sheng [ORNL

    2013-01-01

    Gel polymer electrolytes were synthesized by copolymerization polyethylene glycol methyl ether methacrylate with polyethylene glycol dimethacrylate in the presence of a room temperature ionic liquid, methylpropylpyrrolidinium bis(trifluoromethanesulfonyl)imide (MPPY TFSI). The physical properties of gel polymer electrolytes were characterized by thermal analysis, impedance spectroscopy, and electrochemical tests. The ionic conductivities of the gel polymer electrolytes increased linearly with the amount of MPPY TFSI and were mainly attributed to the increased ion mobility as evidenced by the decreased glass transition temperatures. Li||LiFePO4 cells were assembled using the gel polymer electrolytes containing 80 wt% MPPY TFSI via an in situ polymerization method. A reversible cell capacity of 90 mAh g 1 was maintained under the current density of C/10 at room temperature, which was increased to 130 mAh g 1 by using a thinner membrane and cycling at 50 C.

  14. Effect of Oxygen and Bacteria on the Property of Polymer Gel

    Institute of Scientific and Technical Information of China (English)

    Weidong Jiang; Xiangguo Lu; Xinxia Xu

    2007-01-01

    The viscosity property of Cr3+, Al3+, and compound ion cross-linked polymer gel solution in the anaerobic and aerobic environment was investigated aiming at meeting the practical demand of the oil field. The viscosity reserving effect after adding the biocide and the gelation in the anaerobic and aerobic environments was also studied in the paper. The results indicate that the viscosity of the cross-linked polymer gel solution caused by the water produced in aerobic environment is higher than that in anaerobic environment, and that the viscosity value of the cross-linked polymer gel solutions after adding biocides has improved to some extent and polymer gel has gelated well in anaerobic environment.

  15. High resolution polymer gel dosimetry for small beam irradiation using a 7T micro-MRI scanner

    Energy Technology Data Exchange (ETDEWEB)

    Ding Xuanfeng; Olsen, John; Best, Ryan; Bennett, Marcus; McGowin, Inna; Dorand, Jennifer; Link, Kerry; Bourland, J Daniel, E-mail: dingx6@wfu.ed

    2010-11-01

    The use of small field radiation beams has greatly increased with advanced radiation therapy techniques such as IMRT, rotational IMRT, and stereotactic body radiotherapy. In this work small field 3D dose distributions have been measured with high spatial resolution using polymer gels and 7T micro-MR imaging. A MAGIC (Methacrylic and Ascorbic acid in Gelatin Initiated by Copper) polymer gel {sup [1]} phantom was used to capture the 3D dose distributions for two small field (5 x 5 mm{sup 2} and 10 x 10 mm{sup 2}) for a 6MV x-ray beam. High resolution 3D T2 maps were obtained with 7T micro-MRI (0.156mm x 0.156mm x 1mm, MSME pulse sequence). For comparison T2 maps, the gel phantom was scanned in a 3T MRI clinical scanner (0.254mm x 0.254mm x 2mm, FSE pulse sequence). Normalized 3D dose maps were calculated in Matlab. Results show that 7T micro-MRI 3D gel dosimetry measurements are much more stable, less noisy, and have higher spatial resolution than those obtained using a 3T clinical scanner for the same amount of scan time. In general, 3D gel dosimetry results also agree with simultaneously-obtained radiochromic film dosimetry. This study indicates that the MAGIC polymer gel with 7T micro-MRI for 3D dose readout could potentially be used for small radiation beams, including measurements for micro-beams (field size {approx} 100um).

  16. "JCE" Classroom Activity Connections: NaCl or CaCl[subscript 2], Smart Polymer Gel Tells More

    Science.gov (United States)

    Chen, Yueh-Huey; Lin, Jia-Ying; Wang, Yu-Chen; Yaung, Jing-Fun

    2010-01-01

    This classroom activity connection demonstrates the differences between the effects of NaCl (a salt of monovalent metal ions) and CaCl[subscript 2] (a salt of polyvalent metal ions) on swollen superabsorbent polymer gels. Being ionic compounds, NaCl and CaCl[subscript 2] both collapse the swollen polymer gels. The gel contracted by NaCl reswells…

  17. A HYBRID POLYMER GEL AND ITS STATIC NONERGODICIT

    Institute of Scientific and Technical Information of China (English)

    Yue Zhao; Chi Wu

    2002-01-01

    We used a thermally reversible hybrid gel made of billions of physically jam-packed swollen thermally sensitive poly(N-isopropyl-acrylamide) chemical microgels. Laser light scattering study on a series of such hybrid gels formed at different gelling rates and temperatures revealed that the position-dependence of the scattering speckle pattern (static nonergodicity) came from large voids formed during the sol-gel transition. With a proper preparation, such a nonergodicity could be completely removed, indicating that the static nonergodicity generally observed in a gel is not intrinsic, but comes from the clustering "island" structure formed during the gelation process.

  18. Associative polymers and physical gels derived from natural biopolymers; Polymeres associes et gels physiques derives de biopolymeres naturels

    Energy Technology Data Exchange (ETDEWEB)

    Muller, G.; Huguet, J.; Merle, L.; Grisel, M.; Picton, L.; Bataille, I.; Charpentier, D.; Glinel, K. [CNRS, Polymeres, Biopolymeres et Membranes, Universite de Rouen, 76 - Mont-Saint-Aignan (France)

    1997-04-01

    Polymers are largely used in oil-field operations where the control of rheology of aqueous phases ids of primary importance. Polymers systems showing high viscosity present many advantages as candidates for drilling muds. Associating polymers, i.e. polymers the hydrophilic main chains of which have been properly modified by introducing hydrophobic groups and weak physical ges are good examples of such systems. The different systems chosen to be studied are derived from natural biopolymers. They are: Alkyl derivatives issued from neutral (HEC) and ionic (CMC) cellulosic ether derivatives; alkyl and fluoro alkyl derivatives from neutral (Pull) and ionic (CMP) bacterial polysaccharide pullulane; weak physical gels resulting from complex formation between borate ions and the neutral fungal polysaccharide schizophyllan. The different results are given in tables and figures. (N.C.)

  19. Polymer composite principles applied to hair styling gels.

    Science.gov (United States)

    Wade Rafferty, Denise; Zellia, Joseph; Hasman, Daniel; Mullay, John

    2008-01-01

    A novel approach is taken to understand the mechanical performance of fixative-treated hair tresses. Polymer composite principles are applied to explain the performance. Examples are given for polyacrylate-2 crosspolymer that show that the choice of neutralizer affects the film properties of anionic acrylic polymers by plasticization or by hardening through ionic (physical) crosslinking. The effect of these changes in the polymer film on the composite properties was determined by mechanical stiffness and high-humidity curl retention testing. It is shown that both adhesion to the hair and polymer cohesion are important in determining fixative polymer performance. The implications of the results for the formulation of fixative systems are discussed.

  20. A study of normoxic polymer gel using monomer 2-hydroxyethyl methacrylate (HEMA)

    Energy Technology Data Exchange (ETDEWEB)

    Ishak, Siti Atiqah; Mustafa, Iskandar Shahrim; Rahman, Azhar Abdul [School of Physics, Universiti Sains Malaysia, Pulau Pinang (Malaysia); Moktar, Mohd; Min, Ung Ngie [Radiotherapy Department, University Malaya Medical Centre, Kuala Lumpur (Malaysia)

    2015-04-24

    The aim of this study is to determine the sensitivity of HEMA-polymer gel mixture consist of monomer 2-hydroxyethyl methacrylate (HEMA) with different types of composition. Several composition of HEMA-polymer gel were fabricated and the gels were irradiated with radiation dose between 10 cGy to 100cGy by using x-ray machine and 100 cGy to 1400 cGy by using 6 MV photon beam energy of linear accelerator. The degree of polymerization was evaluated by using magnetic resonance imaging (MRI) with dependence of R2-dose response. Polymer gel consists of cross-linker, anti-oxidant Tetrakis(Hydroxymethyl)phosphonium chloride solution (THPC) and oxygen scavenger hydroquinone shows a stable sensitivity with highest dose dependency. Besides, the results shows the stage polymerization consist of induction, propagation, termination, and chain transfer were dependence with type of chemical mixture and radiation dose. Thus, normoxic HEMA-polymer gel with the different gel formulations can have a better dose resolution and an appropriate recipe must be selected to increase of the sensitivity required and the stability of the dosimeter.

  1. Clinically Relevant Anticancer Polymer Paclitaxel Therapeutics

    International Nuclear Information System (INIS)

    The concept of utilizing polymers in drug delivery has been extensively explored for improving the therapeutic index of small molecule drugs. In general, polymers can be used as polymer-drug conjugates or polymeric micelles. Each unique application mandates its own chemistry and controlled release of active drugs. Each polymer exhibits its own intrinsic issues providing the advantage of flexibility. However, none have as yet been approved by the U.S. Food and Drug Administration. General aspects of polymer and nano-particle therapeutics have been reviewed. Here we focus this review on specific clinically relevant anticancer polymer paclitaxel therapeutics. We emphasize their chemistry and formulation, in vitro activity on some human cancer cell lines, plasma pharmacokinetics and tumor accumulation, in vivo efficacy, and clinical outcomes. Furthermore, we include a short review of our recent developments of a novel poly(l-γ-glutamylglutamine)-paclitaxel nano-conjugate (PGG-PTX). PGG-PTX has its own unique property of forming nano-particles. It has also been shown to possess a favorable profile of pharmacokinetics and to exhibit efficacious potency. This review might shed light on designing new and better polymer paclitaxel therapeutics for potential anticancer applications in the clinic

  2. Clinically Relevant Anticancer Polymer Paclitaxel Therapeutics

    Directory of Open Access Journals (Sweden)

    Danbo Yang

    2010-12-01

    Full Text Available The concept of utilizing polymers in drug delivery has been extensively explored for improving the therapeutic index of small molecule drugs. In general, polymers can be used as polymer-drug conjugates or polymeric micelles. Each unique application mandates its own chemistry and controlled release of active drugs. Each polymer exhibits its own intrinsic issues providing the advantage of flexibility. However, none have as yet been approved by the U.S. Food and Drug Administration. General aspects of polymer and nano-particle therapeutics have been reviewed. Here we focus this review on specific clinically relevant anticancer polymer paclitaxel therapeutics. We emphasize their chemistry and formulation, in vitro activity on some human cancer cell lines, plasma pharmacokinetics and tumor accumulation, in vivo efficacy, and clinical outcomes. Furthermore, we include a short review of our recent developments of a novel poly(L-g-glutamylglutamine-paclitaxel nano-conjugate (PGG-PTX. PGG-PTX has its own unique property of forming nano-particles. It has also been shown to possess a favorable profile of pharmacokinetics and to exhibit efficacious potency. This review might shed light on designing new and better polymer paclitaxel therapeutics for potential anticancer applications in the clinic.

  3. Stable Lithium Deposition Generated from Ceramic-Cross-Linked Gel Polymer Electrolytes for Lithium Anode.

    Science.gov (United States)

    Tsao, Chih-Hao; Hsiao, Yang-Hung; Hsu, Chun-Han; Kuo, Ping-Lin

    2016-06-22

    In this work, a composite gel electrolyte comprising ceramic cross-linker and poly(ethylene oxide) (PEO) matrix is shown to have superior resistance to lithium dendrite growth and be applicable to gel polymer lithium batteries. In contrast to pristine gel electrolyte, these nanocomposite gel electrolytes show good compatibility with liquid electrolytes, wider electrochemical window, and a superior rate and cycling performance. These silica cross-linkers allow the PEO to form the lithium ion pathway and reduce anion mobility. Therefore, the gel not only features lower polarization and interfacial resistance, but also suppresses electrolyte decomposition and lithium corrosion. Further, these nanocomposite gel electrolytes increase the lithium transference number to 0.5, and exhibit superior electrochemical stability up to 5.0 V. Moreover, the lithium cells feature long-term stability and a Coulombic efficiency that can reach 97% after 100 cycles. The SEM image of the lithium metal surface after the cycling test shows that the composite gel electrolyte with 20% silica cross-linker forms a uniform passivation layer on the lithium surface. Accordingly, these features allow this gel polymer electrolyte with ceramic cross-linker to function as a high-performance lithium-ionic conductor and reliable separator for lithium metal batteries. PMID:27247991

  4. A flexible Li polymer primary cell with a novel gel electrolyte based on poly(acrylonitrile)

    Science.gov (United States)

    Akashi, Hiroyuki; Tanaka, Ko-ichi; Sekai, Koji

    The performance of a Li polymer primary cell with fire-retardant poly(acrylonitrile) (PAN)-based gel electrolytes is reported. By optimizing electrodes, electrolytes, the packaging material, and the structural design of the polymer cell, we succeeded in developing a "film-like" Li polymer primary cell with sufficient performance for practical use. The cell is flexible and less than 0.5 mm thick, which makes it suitable for a power source for some smart devices, such as an IC card. Fast cation conduction in the gel electrolyte minimizes the drop of the discharge capacity even at -20 °C. The high chemical stability of the gel electrolytes and the new packaging material allow the self-discharge rate to be limited to under 4.3%, which is equivalent to that of conventional coin-shaped or cylindrical Li-MnO 2 cells.

  5. Multi-Stimuli-Responsive Polymer Materials: Particles, Films, and Bulk Gels.

    Science.gov (United States)

    Cao, Zi-Quan; Wang, Guo-Jie

    2016-06-01

    Stimuli-responsive polymers have received tremendous attention from scientists and engineers for several decades due to the wide applications of these smart materials in biotechnology and nanotechnology. Driven by the complex functions of living systems, multi-stimuli-responsive polymer materials have been designed and developed in recent years. Compared with conventional single- or dual-stimuli-based polymer materials, multi-stimuli-responsive polymer materials would be more intriguing since more functions and finer modulations can be achieved through more parameters. This critical review highlights the recent advances in this area and focuses on three types of multi-stimuli-responsive polymer materials, namely, multi-stimuli-responsive particles (micelles, micro/nanogels, vesicles, and hybrid particles), multi-stimuli-responsive films (polymer brushes, layer-by-layer polymer films, and porous membranes), and multi-stimuli-responsive bulk gels (hydrogels, organogels, and metallogels) from recent publications. Various stimuli, such as light, temperature, pH, reduction/oxidation, enzymes, ions, glucose, ultrasound, magnetic fields, mechanical stress, solvent, voltage, and electrochemistry, have been combined to switch the functions of polymers. The polymer design, preparation, and function of multi-stimuli-responsive particles, films, and bulk gels are comprehensively discussed here. PMID:27153184

  6. Multi-Stimuli-Responsive Polymer Materials: Particles, Films, and Bulk Gels.

    Science.gov (United States)

    Cao, Zi-Quan; Wang, Guo-Jie

    2016-06-01

    Stimuli-responsive polymers have received tremendous attention from scientists and engineers for several decades due to the wide applications of these smart materials in biotechnology and nanotechnology. Driven by the complex functions of living systems, multi-stimuli-responsive polymer materials have been designed and developed in recent years. Compared with conventional single- or dual-stimuli-based polymer materials, multi-stimuli-responsive polymer materials would be more intriguing since more functions and finer modulations can be achieved through more parameters. This critical review highlights the recent advances in this area and focuses on three types of multi-stimuli-responsive polymer materials, namely, multi-stimuli-responsive particles (micelles, micro/nanogels, vesicles, and hybrid particles), multi-stimuli-responsive films (polymer brushes, layer-by-layer polymer films, and porous membranes), and multi-stimuli-responsive bulk gels (hydrogels, organogels, and metallogels) from recent publications. Various stimuli, such as light, temperature, pH, reduction/oxidation, enzymes, ions, glucose, ultrasound, magnetic fields, mechanical stress, solvent, voltage, and electrochemistry, have been combined to switch the functions of polymers. The polymer design, preparation, and function of multi-stimuli-responsive particles, films, and bulk gels are comprehensively discussed here.

  7. Investigation of optimal scanning protocol for X-ray computed tomography polymer gel dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Sellakumar, P. [Bangalore Institute of Oncology, 44-45/2, II Cross, RRMR Extension, Bangalore 560 027 (India)], E-mail: psellakumar@rediffmail.com; James Jebaseelan Samuel, E. [School of Science and Humanities, VIT University, Vellore 632 014 (India); Supe, Sanjay S. [Department of Radiation Physics, Kidwai Memorial Institute of Oncology, Hosur Road, Bangalore 560 027 (India)

    2007-11-15

    X-ray computed tomography is one of the potential tool used to evaluate the polymer gel dosimeters in three dimensions. The purpose of this study is to investigate the factors which affect the image noise for X-ray CT polymer gel dosimetry. A cylindrical water filled phantom was imaged with single slice Siemens Somatom Emotion CT scanner. The imaging parameters like tube voltage, tube current, slice scan time, slice thickness and reconstruction algorithm were varied independently to study the dependence of noise on each other. Reductions of noise with number of images to be averaged and spatial uniformity of the image were also investigated. Normoxic polymer gel PAGAT was manufactured and irradiated using Siemens Primus linear accelerator. The radiation induced change in CT number was evaluated using X-ray CT scanner. From this study it is clear that image noise is reduced with increase in tube voltage, tube current, slice scan time, slice thickness and also reduced with increasing the number of images averaged. However to reduce the tube load and total scan time, it was concluded that tube voltage of 130 kV, tube current of 200 mA, scan time of 1.5 s, slice thickness of 3 mm for high dose gradient and 5 mm for low dose gradient were optimal scanning protocols for this scanner. Optimum number of images to be averaged was concluded to be 25 for X-ray CT polymer gel dosimetry. Choice of reconstruction algorithm was also critical. From the study it is also clear that CT number increase with imaging tube voltage and shows the energy dependency of polymer gel dosimeter. Hence for evaluation of polymer gel dosimeters with X-ray CT scanner needs the optimization of scanning protocols to reduce the image noise.

  8. Investigation of optimal scanning protocol for X-ray computed tomography polymer gel dosimetry

    International Nuclear Information System (INIS)

    X-ray computed tomography is one of the potential tool used to evaluate the polymer gel dosimeters in three dimensions. The purpose of this study is to investigate the factors which affect the image noise for X-ray CT polymer gel dosimetry. A cylindrical water filled phantom was imaged with single slice Siemens Somatom Emotion CT scanner. The imaging parameters like tube voltage, tube current, slice scan time, slice thickness and reconstruction algorithm were varied independently to study the dependence of noise on each other. Reductions of noise with number of images to be averaged and spatial uniformity of the image were also investigated. Normoxic polymer gel PAGAT was manufactured and irradiated using Siemens Primus linear accelerator. The radiation induced change in CT number was evaluated using X-ray CT scanner. From this study it is clear that image noise is reduced with increase in tube voltage, tube current, slice scan time, slice thickness and also reduced with increasing the number of images averaged. However to reduce the tube load and total scan time, it was concluded that tube voltage of 130 kV, tube current of 200 mA, scan time of 1.5 s, slice thickness of 3 mm for high dose gradient and 5 mm for low dose gradient were optimal scanning protocols for this scanner. Optimum number of images to be averaged was concluded to be 25 for X-ray CT polymer gel dosimetry. Choice of reconstruction algorithm was also critical. From the study it is also clear that CT number increase with imaging tube voltage and shows the energy dependency of polymer gel dosimeter. Hence for evaluation of polymer gel dosimeters with X-ray CT scanner needs the optimization of scanning protocols to reduce the image noise

  9. Comparison of Energy Dependence of PAGAT Polymer Gel Dosimeter with Electron and Photon Beams using Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    B. Azadbakht

    2012-02-01

    Full Text Available The purpose of this study was to evaluate dependence of PAGAT polymer gel dosimeter 1/T2 on different electron and photon energies for a standard clinically used 60Co therapy unit and an electa linear accelerator.Using MRI, the formulation to give the maximum change in the transverse relaxation rate R2(1/T2 was determined to be 4.5% N,N'-methylen-bis-acrylamide(bis, 4.5% acrylamid(AA, 5% gelatine, 5 mM tetrakis (hydroxymethyl phosphonium chloride (THPC, 0.01 mM hydroquinone (HQ and 86% HPLC(Water. When the preparation of final polymer gel solution is completed, it is transferred into phantoms and allowed to set by storage in a refrigerator at about 4°C. The optimal post-manufacture irradiation and post imaging times were both determined to be 24 h. The sensitivity of PAGAT polymer gel dosimeter with irradiation of photon and electron beams was represented by the slope of calibration curve in the linear region measured for each modality. The response of PAGAT gel with photon and electron beams is very similar in the lower dose region. The R2-dose response was linear up to 30 Gy and the R2-dose response of the PAGAT polymer gel dosimeter is linear between 10 to 30 Gy. In electron beams the R2-dose response for doses less than 3 Gy is not exact, but in photon beams the R2-dose response for doses less than 2Gy is not exact. Dosimeter energy dependence was studied for electron energies of 4, 12 and 18MeV and photon energies of 1.25, 4, 6 and 18 MV. Evaluation of dosimeters were performed on Siemens Symphony, Germany 1.5T Scanner in the head coil. In this study no trend in polymer-gel dosimeter 1/T2 dependence was found on mean energy for electron and photon beams.

  10. Gel Formation in Polymers Undergoing Radiation-Induced Crosslinking and Scission

    DEFF Research Database (Denmark)

    Handlos, V. N.; Singer, Klaus Albert Julius

    1976-01-01

    A study was made of the solubility of irradiated polyethylene. The experimental data were treated according to the Saito-Inokuti theory for gel formation in polymers exposed to ionizing radiation. Among other things, this theory is based upon the molecular weight distribution of the unirradiated...... polymer; in the present work, the actual distributions were determined by high-temperature gel permeation chromatography and corrected for long-chain branching. Under these circumstances, good agreement between theory and experimental data was obtained, which allowed the determination of the radiation...

  11. Formulation development and evaluation of innovative two-polymer (SR-2P) bioadhesive vaginal gel.

    Science.gov (United States)

    Podaralla, Satheesh; Alt, Carsten; Shankar, Gita N

    2014-08-01

    The main objective of this investigation was to study the feasibility of developing a vaginal bioadhesive microbicide using a SRI's proprietary two-polymer gel platform (SR-2P). Several formulations were prepared with different combinations of temperature-sensitive polymer (Pluronic® F-127) and mucoadhesive polymer (Noveon® AA-1), producing gels of different characteristics. Prototype polymeric gels were evaluated for pH, osmolality, buffering capacity, and viscosity under simulated vaginal semen dilutions, and bioadhesivity using ex vivo mini pig vaginal tissues and texture analyzer. The pH of the polymeric gel formulations ranged from 5.1 to 6.4; the osmolality varied from 13 to 173 mOsm. Absolute viscosity ranged from 513 to 3,780 cPs, and was significantly reduced (1.5- to 3-fold) upon incubation with simulated vaginal and semen fluid mixture. Among the tested gels (indicated in the middle row as a molar ratio of a mixture of Noveon vs. Pluronic), only SR-2P retained gel structure upon dilution with simulated fluids and mild simulated coital stress. The pH of the SR-2P gel was maintained at about 4.6 in simulated vaginal fluid and also showed high peak force of adhesion in mini pig vaginal tissue. Furthermore, SR-2P gel caused no or only minimal irritation in a mouse vaginal irritation model. The results of this preliminary study demonstrated the potential application of SR-2P gel as a vaginal microbicide vehicle for delivery of anti-HIV agents. PMID:24781671

  12. Polymer Physics Prize: Designing ''Materials that Compute'': Exploiting the Properties of Self-oscillating Polymer Gels

    Science.gov (United States)

    Balazs, Anna

    Lightweight, deformable materials that can sense and respond to human touch and motion can be the basis of future wearable computers, where the material itself will be capable of performing computations. To facilitate the creation of ''materials that compute'', we draw from two emerging modalities for computation: chemical computing, which relies on reaction-diffusion mechanisms to perform operations, and oscillatory computing, which performs pattern recognition through synchronization of coupled oscillators. Chemical computing systems, however, suffer from the fact that the reacting species are coupled only locally; the coupling is limited by diffusion as the chemical waves propagate throughout the system. Additionally, oscillatory computing systems have not utilized a potentially wearable material. To address both these limitations, we develop the first model for coupling self-oscillating polymer gels to a piezoelectric (PZ) micro-electro-mechanical system (MEMS). The resulting transduction between chemo-mechanical and electrical energy creates signals that can be propagated quickly over long distances and thus, permits remote, non-diffusively coupled oscillators to communicate and synchronize. The oscillators can be organized into arbitrary topologies because the electrical connections lift the limitations of diffusive coupling. Using our model, we predict the synchronization behavior that can be used for computational tasks, ultimately enabling ''materials that compute''.

  13. Hemoglobin-imprinted polymer gel prepared using modified glucosamine as functional monomer

    Institute of Scientific and Technical Information of China (English)

    Hai Li Zhao; Tian Ying Guo; Yong Qing Xia; Mou Dao Song

    2008-01-01

    A new functional glycomonomer was obtained from modified glucosamine.Hemoglobin-imprinted polymer gel was prepared with allyl-bromide modified glucosamine as functional monomer,poly(ethylene-glycol)diaorylate(PEGDA)as cross-linker and ammonium persulfate[(NH4)2S2O8]/sodium hydrogen sulfite(NaHSO3)as initiators in a phosphate buffer.The adsorption capacity and selective adsorption of the molecular imprinting polymer(MIP)were also discussed.

  14. Sensitivity calibration procedures in optical-CT scanning of BANG®3 polymer gel dosimeters

    OpenAIRE

    Xu, Y; Wuu, Cheng-Shie; Maryanski, Marek J.

    2010-01-01

    The dose response of the BANG®3 polymer gel dosimeter (MGS Research Inc., Madison, CT) was studied using the OCTOPUS™ laser CT scanner (MGS Research Inc., Madison, CT). Six 17 cm diameter and 12 cm high Barex cylinders, and 18 small glass vials were used to house the gel. The gel phantoms were irradiated with 6 and 10 MV photons, as well as 12 and 16 MeV electrons using a Varian Clinac 2100EX. Three calibration methods were used to obtain the dose response curves: (a) Optical density measurem...

  15. A novel method of estimating dose responses for polymer gels using texture analysis of scanning electron microscopy images.

    Directory of Open Access Journals (Sweden)

    Cheng-Ting Shih

    Full Text Available Polymer gels are regarded as a potential dosimeter for independent validation of absorbed doses in clinical radiotherapy. Several imaging modalities have been used to convert radiation-induced polymerization to absorbed doses from a macro-scale viewpoint. This study developed a novel dose conversion mechanism by texture analysis of scanning electron microscopy (SEM images. The modified N-isopropyl-acrylamide (NIPAM gels were prepared under normoxic conditions, and were administered radiation doses from 5 to 20 Gy. After freeze drying, the gel samples were sliced for SEM scanning with 50×, 500×, and 3500× magnifications. Four texture indices were calculated based on the gray level co-occurrence matrix (GLCM. The results showed that entropy and homogeneity were more suitable than contrast and energy as dose indices for higher linearity and sensitivity of the dose response curves. After parameter optimization, an R (2 value of 0.993 can be achieved for homogeneity using 500× magnified SEM images with 27 pixel offsets and no outlier exclusion. For dose verification, the percentage errors between the prescribed dose and the measured dose for 5, 10, 15, and 20 Gy were -7.60%, 5.80%, 2.53%, and -0.95%, respectively. We conclude that texture analysis can be applied to the SEM images of gel dosimeters to accurately convert micro-scale structural features to absorbed doses. The proposed method may extend the feasibility of applying gel dosimeters in the fields of diagnostic radiology and radiation protection.

  16. DEVELOPMENT OF POLYMER GEL SYSTEMS TO IMPROVE VOLUMETRIC SWEEP AND REDUCE PRODUCING WATER/OIL RATIOS

    Energy Technology Data Exchange (ETDEWEB)

    G. Paul Willhite; Stan McCool; Don W. Green; Min Cheng; Rajeev Jain; Tuan Nguyen

    2003-11-01

    Gelled polymer treatments are applied to oil reservoirs to increase oil production and to reduce water production by altering the fluid movement within the reservoir. This report describes the results of the first year of a three-year research program that is aimed at the understanding of the chemistry of gelation and the fundamental mechanisms that alter the flows of oil and water in reservoir rocks after a gel treatment. Work has focused on a widely-applied system in field applications, the partially hydrolyzed polyacrylamide-chromium acetate gel. Gelation occurs by network formation through the crosslinking of polyacrylamide molecules as a result of reaction with chromium acetate. The initial reaction between chromium acetate and one polymer is referred to as the uptake reaction. The uptake reaction was studied as functions of chromium and polymer concentrations and pH values. Experimental data were regressed to determine a rate equation that describes the uptake reaction of chromium by polyacrylamide. Pre-gel aggregates form and grow as the reactions between chromium acetate and polyacrylamide proceed. A statistical model that describes the growth of pre-gel aggregates was developed using the theory of branching processes. The model gives molecular weight averages that are expressed as functions of the conversion of the reactive sites on chromium acetate or on the polymer molecule. Results of the application of the model correlate well with experimental data of viscosity and weight-average molecular weight and gives insights into the gelation process. A third study addresses the flow of water and oil in rock material after a gel treatment. Previous works have shown that gel treatments usually reduce the permeability to water to a greater extent than the permeability to oil is reduced. This phenomenon is referred to as disproportionate permeability reduction (DPR). Flow experiments were conducted to determine the effect of polymer and chromium concentrations on

  17. Fracturing Fluid (Guar Polymer Gel Degradation Study by using Oxidative and Enzyme Breaker

    Directory of Open Access Journals (Sweden)

    Aung Kyaw

    2012-06-01

    Full Text Available Oxidative and enzyme breakers are used in this research project with the main objective to study on the degradation pattern of fracturing fluid (i.e., guar polymer gel as a function of time, temperature and breaker concentration itself. The fracturing fluid used in hydraulic fracturing or frac pack contain a chemical breakers to reduce the viscosity of the fluid intermingled with the proppant. Chemical breakers reduce viscosity of the guar polymer by cleaving the polymer into small-molecular-weight fragments. The reduction of viscosity will facilitate the flow-back of residual polymer providing rapid recovery of polymer from proppant pack. Ineffective breakers or misapplication of breakers can result in screen-outs or flow-back of viscous fluids both of which can significantly decrease the well productivity. Breaker activity of low to medium temperature range oxidative and enzyme breaker systems was evaluated. ViCon NF an oxidative breaker (Halliburton product and GBW 12- CD an enzyme breaker (BJ Services product were used in this research project with the main objective to study on the degradation pattern of fracturing fluid (guar polymer gel as a function of (time, temperature and breaker concentration itself. This study provides focuses on the way to mix the fracturing fluid, compositions of the fracturing fluid and how to conduct the crosslink and break test. Crosslink test indicate the optimum cross-linker concentration to produce good crosslink gel and the break test gave the characteristic of the gel during degradation process and also the break time. Besides relying on the laboratory experiment, information obtained from research on SPE and US Pattern papers were used to make a comparison study on oxidative and enzyme breakers properties. Degradation pattern observed from the break test showed that reduction in gel viscosity depends on time, temperature and breaker concentration. Observations from experiment also revealed that small

  18. A novel and high-effective redox-mediated gel polymer electrolyte for supercapacitor

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Alkali and P-phenylenediamine doped polyvinyl alcohol gel electrolyte is prepared. • The PVA-KOH-PPD gel electrolyte can also be used as separator. • The introduction of PPD increases the ionic conductivity of electrolyte. • The supercapacitor exhibits flexible and high energy density. - Abstract: A supercapacitor utilize a novel redox-mediated gel polymer (PVA-KOH-PPD) as electrolyte and separator, and activated carbon as electrodes is assembled. The PVA-KOH-PPD gel polymer as potential electrolyte for supercapacitor is investigated by cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy techniques. It is found that the supercapacitor exhibits high ionic conductivity (25 mS cm−1), large electrode specific capacitance (611 F g−1) and high energy density (82.56 Wh kg−1). The high performance is attributed to the addition of quick redox reactions at the electrolyte|electrode interface as PPD undergoes a two-proton/two-electron reduction and oxidation during cycling. Furthermore, the supercapacitor with PVA-KOH-PPD gel polymer shows excellent charge-discharge stability, after 1000 charge-discharge cycles, the supercapacitor still retains a high electrode specific capacitance of 470 F g−1. It is believed that the idea using redox mediator has a good prospect for improving the performances of supercapacitors

  19. Interpretation of mucoadhesive properties of polymer gel preparations using a tensile strength method.

    Science.gov (United States)

    Hägerström, H; Edsman, K

    2001-12-01

    We have developed a new tensile strength method for assessing mucoadhesive properties of polymer gels utilising freshly excised porcine nasal mucosa and a texture analyser. In conjunction with this, we propose a method for interpreting the mucoadhesive properties that is based on reasoning about the locus of the failure of a mucoadhesive joint. This involves measuring the cohesiveness of the gel and the mucus layer, respectively, and comparing these results with those obtained from a mucoadhesion measurement. Linear polymers (sodium carboxymethylcellulose, poly(acrylic acid) and sodium hyaluronate) and a cross-linked polymer (poly(acrylic acid)) were used as model polymers in this study. It was shown that the withdrawal speed of the probe should be low, about 0.1 mm s(-1), and that a contact time of 2 min was sufficient. In the mucoadhesion measurements there was no dependence of the results on the contact time in the interval 2-20 min. The tensile work appeared to be more applicable than the fracture strength for interpreting mucoadhesive properties. Furthermore, it was concluded that the interpretation procedure offers a good basis by which to assess whether the measured tensile work reflects a cohesive failure of the gel or a true interaction of the gel with the mucus layer. PMID:11804389

  20. Polymer gel dosimetry of an electron beam in the presence of a magnetic field

    Science.gov (United States)

    Vandecasteele, J.; De Deene, Y.

    2013-06-01

    The effect of a strong external magnetic field on 4 MeV electron beam was measured with polymer gel dosimetry. The measured entrance dose distribution was compared with a calculated fluence map. The magnetic field was created by use of two permanent Neodymium (NdFeB) magnets that were positioned perpendicular to the electron beam. The magnetic field between the magnets was measured with Hall sensors. Based on the magnetic field measurement and the law of Biot-Savart, the magnetic field distribution was extrapolated. Electron trajectories were calculated using a relativistic Lorentz force operator. Although the simplified computational model that was applied, the shape and position of the calculated entrance fluence map are found to be in good agreement with the measured dose distribution in the first layer of the phantom. In combination with the development of low density polymer gel dosimeters, these preliminary results show the potential of 3D gel dosimetry in MRI-linac applications.

  1. Novel composition of polymer gel dosimeters based on N-(Hydroxymethyl)acrylamide for radiation therapy

    Science.gov (United States)

    Basfar, Ahmed A.; Moftah, Belal; Rabaeh, Khalid A.; Almousa, Akram A.

    2015-07-01

    A new composition of polymer gel dosimeters is developed based on radiation induced polymerization of N-(Hydroxymethyl)acrylamide (NHMA) for radiotherapy treatment planning. The dosimeters were irradiated by 10 MV photon beam of a medical linear accelerator at a constant dose rate of 600 cGy/min with doses up to 20 Gy. The polymerization occurs and increases with increasing absorbed dose. The dose response of polymer gel dosimeters was studied using nuclear magnetic imaging (NMR) for relaxation rate (R2) of water proton. Dose rate, energy of radiation and the stability of the polymerization after irradiation were investigated. No appreciable effects of these parameters on the performance of the novel gel dosimeters were observed.

  2. On the mechanical characterization and modeling of polymer gel brain substitute under dynamic rotational loading.

    Science.gov (United States)

    Fontenier, B; Hault-Dubrulle, A; Drazetic, P; Fontaine, C; Naceur, H

    2016-10-01

    The use of highly sensitive soft materials has become increasingly apparent in the last few years in numerous industrial fields, due to their viscous and damping nature. Unfortunately these materials remain difficult to characterize using conventional techniques, mainly because of the very low internal forces supported by these materials especially under high strain-rates of deformation. The aim of this work is to investigate the dynamic response of a polymer gel brain analog material under specific rotational-impact experiments. The selected polymer gel commercially known as Sylgard 527 has been studied using a specific procedure for its experimental characterization and numerical modeling. At first an indentation experiment was conducted at several loading rates to study the strain rate sensitivity of the Sylgard 527 gel. During the unloading several relaxation tests were performed after indentation, to assess the viscous behavior of the material. A specific numerical procedure based on moving least square approximation and response surface method was then performed to determine adequate robust material parameters of the Sylgard 527 gel. A sensitivity analysis was assessed to confirm the robustness of the obtained material parameters. For the validation of the obtained material model, a second experiment was conducted using a dynamic rotational loading apparatus. It consists of a metallic cylindrical cup filled with the polymer gel and subjected to an eccentric transient rotational impact. Complete kinematics of the cup and the large strains induced in the Sylgard 527 gel, have been recorded at several patterns by means of optical measurement. The whole apparatus was modeled by the Finite Element Method using explicit dynamic time integration available within Ls-dyna(®) software. Comparison between the physical and the numerical models of the Sylgard 527 gel behavior under rotational choc shows excellent agreements.

  3. In-phantom dosimetry for BNCT with Fricke and normoxic-polymer gels

    Science.gov (United States)

    Gambarini, G.; Agosteo, S.; Carrara, M.; Gay, S.; Mariani, M.; Pirola, L.; Vanossi, E.

    2006-05-01

    Measurements of in-phantom dose distributions and images are important for Boron Neutron Capture Therapy treatment planning. The method for spatial determination of absorbed doses in thermal or epithermal neutron fields, based on Fricke-xylenol-orange-infused gel dosimeters in form of layers, has revealed to be very reliable, as gel layer dosimeters give the possibility of obtaining spatial dose distributions and measurements of each dose contribution in neutron fields, by means of a properly studied procedure. Quite recently, BNCT has been applied to treat liver metastases; in this work the results of in-phantom dosimetry for explanted liver in BNCT treatments are described. Moreover, polyacrylamide gel (PAG) dosimeters in which a polymerization process appears as a consequence of absorbed dose, have been recently tested, because of their characteristic absence of diffusion. In fact, due to the diffusion of ferric ions, Fricke-gel dosimeters require prompt analysis after exposure to avoid spatial information loss. In this work the preliminary results of a study about the reliability of polymer gel in BNCT dosimetry are also discussed. Gel layers have been irradiated in a phantom exposed in the thermal column of the TRIGA MARK II reactor (Pavia). The results obtained with the two kinds of gel dosimeter have been compared.

  4. Photon and neutron kerma coefficients for polymer gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    El-Khayatt, A.M., E-mail: Ahmed_el_khayatt@yahoo.com [Physics Department, College of Science, Al Imam Mohammad Ibn Saud Islamic University (IMSIU) (Saudi Arabia); Reactor Physics Department, Nuclear Research Centre, Atomic Energy Authority, 13759 Cairo (Egypt); Vega-Carrillo, Hector Rene [Unidad Academica de Estudios Nucleares, Universidad Autonoma de Zacatecas, C. Cipres 10, Fracc. La Peñuela, 98068 Zacatecas, Zac. (Mexico)

    2015-08-21

    Neutron and gamma ray kerma coefficients were calculated for 17 3D dosimeters, for the neutron and gamma ray energy ranges extend from 2.53×10{sup −8} to 29 MeV and from 1.0×10{sup −3} to 20 MeV, respectively. The calculated kermas given here for discrete energies and the kerma coefficients are referred to as “point-wise data”. Curves of gamma ray kermas showed slight dips at about 60 keV for most 3D dosimeters. Also, a noticeable departure between thermal and epithermal neutrons kerma sets for water and polymers has been observed. Finally, the obtained results could be useful for dose estimation in the studied 3D dosimeters. - Highlights: • Neutron and gamma ray kerma coefficients were calculated in 17 3D dosimeters. • Curves of gamma-ray kermas showed slight dips at about 60 keV. • Disagreement between neutron kermas for water and polymers has been observed. • The obtained results could be useful for dose estimation in the studied dosimeters.

  5. Technical Note: Preliminary investigations into the use of a functionalised polymer to reduce diffusion in Fricke gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S. T., E-mail: s164.smith@qut.edu.au; Masters, K.-S.; Hosokawa, K.; Blinco, J. P.; Trapp, J. V. [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane 4000 (Australia); Crowe, S. B. [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane 4000, Australia and Cancer Care Services, Royal Brisbane and Women’s Hospital, Brisbane 4006 (Australia); Kairn, T. [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane 4000, Australia and Genesis Cancer Care Queensland, Brisbane 4066 (Australia)

    2015-12-15

    Purpose: A modification of the existing PVA-FX hydrogel has been made to investigate the use of a functionalised polymer in a Fricke gel dosimetry system to decrease Fe{sup 3+} diffusion. Methods: The chelating agent, xylenol orange, was chemically bonded to the gelling agent, polyvinyl alcohol (PVA) to create xylenol orange functionalised PVA (XO-PVA). A gel was created from the XO-PVA (20% w/v) with ferrous sulfate (0.4 mM) and sulfuric acid (50 mM). Results: This resulted in an optical density dose sensitivity of 0.014 Gy{sup −1}, an auto-oxidation rate of 0.0005 h{sup −1}, and a diffusion rate of 0.129 mm{sup 2} h{sup −1}; an 8% reduction compared to the original PVA-FX gel, which in practical terms adds approximately 1 h to the time span between irradiation and accurate read-out. Conclusions: Because this initial method of chemically bonding xylenol orange to polyvinyl alcohol has inherently low conversion, the improvement on existing gel systems is minimal when compared to the drawbacks. More efficient methods of functionalising polyvinyl alcohol with xylenol orange must be developed for this system to gain clinical relevance.

  6. Correlation between ionic conductivity and fluidity of polymer gel electrolytes containing NH4CF3SO3

    Indian Academy of Sciences (India)

    Harinder Pal Singh; Rajiv Kumar; S S Sekhon

    2005-08-01

    Nonaqueous polymer gel electrolytes containing ammonium triflate (NH4CF3SO3) and dimethylacetamide (DMA) with polymethylmethacrylate (PMMA) as the gelling polymer have been synthesized which show high value of conductivity (∼ 10-2 S/cm) at 25°C. The conductivity of polymer gel electrolytes containing different concentrations of NH4CF3SO3 shows a small decrease with the addition of PMMA and this has been correlated with the variation of fluidity of these gel electrolytes. The small decrease in conductivity with PMMA addition shows that polymer plays the role of stiffener and this is supported by FTIR results which also indicates the absence of any active interaction between polymer and NH4CF3SO3 in these gel electrolytes.

  7. Autonomous Oscillation of Nonthermoresponsive Polymers and Gels Induced by the Belousov–Zhabotinsky Reaction

    Directory of Open Access Journals (Sweden)

    Yusuke Hara

    2013-09-01

    Full Text Available This review introduces the self-oscillating behavior of two types of nonthermoresponsive polymer systems with Ru catalyst moieties for the Belousov-Zhabotinsky (BZ reaction: one with a poly-vinylpyrrolidone (PVP main chain, and the other with a poly(2-propenamide (polyacrylamide (PAM main chain. The amplitude of the VP-based self-oscillating polymer chain and the activation energy for self-oscillation are hardly affected by the initial concentrations of the BZ substrates. The influences of the initial concentrations of the BZ substrates and the temperature on the period of the swelling-deswelling self-oscillation are examined in detail. Logarithmic plots of the period against the initial concentration of one BZ substrate, when the concentrations of the other two BZ substrates are fixed, show good linear relationships. The period of the swelling-deswelling self-oscillation decreases with increasing temperature, in accordance with the Arrhenius equation. The maximum frequency (0.5 Hz of the poly(VP-co-Ru(bpy3 gel is 20 times that of the poly(NIPAAm-co-Ru(bpy3 gel. It is also demonstrated that the amplitude of the volume self-oscillation for the gel has a tradeoff with the self-oscillation period. In addition, this review reports the self-oscillating behavior of an AM-based self-oscillating polymer chain as compared to that of the VP-based polymer chain.

  8. Highly compliant shape memory polymer gels for tunable damping and reversible adhesion

    Science.gov (United States)

    Mrozek, Randy A.; Berg, Michael C.; Gold, Christopher S.; Leighliter, Brad; Morton, Jeffrey T.; Lenhart, Joseph L.

    2016-02-01

    Materials that can dynamically change their properties to better adapt to the local environment have potential utility in robotics, aerospace, and coatings. For some of these applications, most notably robotics, it is advantageous for these responsive materials to be highly compliant in an effort to provide dynamic changes in adhesion and mechanical damping within a broad temperature operational environment. In this report, non-aqueous, highly compliant shape-memory polymer gels are developed by incorporating a low density of chemical cross-links into a physically cross-linked thermoplastic elastomer gel. Chemical cross-linkers were evaluated by varying there size and degree of functionality to determine the impact on the mechanical and adhesive properties. As a result of the chemical cross-linking, the gels exhibit modulus plateaus around room temperature and at elevated temperatures above 100 °C, where the thermoplastic elastomer gel typically melts. The materials were designed so that moduli in the plateaued regions were above and below the Dahlquist criteria of 4 × 104 Pa, respectively, where materials with a modulus below this value typically exhibit an increase in adhesion. The shape memory polymer gels were also integrated into fiber-reinforced composites to determine the temperature-dependent changes in mechanical damping. It is anticipated that this work will provide insight into materials design to provide dynamic changes in adhesion and damping to improve robotic appendage manipulation and platform mobility.

  9. Effect of pH grade on polymer-gel dosimeter and its brachytherapy application

    International Nuclear Information System (INIS)

    To evaluate impact of pH grade on characteristics of polymer-gel dosimeter and its application in dose distribution verification in brachytherapy. A polymer-gel dosimeter based on radiation induced polymerization and crosslinking of acrylic monomers (acrylic acid, N,N' methylen-bis-acrylamide) was investigated with respect to its pH grade. pH grade of a dosimeter was varied by concentration of natrium hydroxide. Afterwards, dosimeter was split into several samples which were uniformly irradiated with Co-60 gamma rays. The range of doses applied was usually from 0 to 50 Gy with the main interest in region up to 20 Gy. Evaluation of dosimeter dose response was performed using MRI (T2). Dose response curves obtained were evaluated with respect to pH grade as a parameter. In parallel, there was studied temperature resistance (melting temperature) of gels with various pH grade. pH grade modified polymer-gel dosimeter was then used to compare dose distribution calculated with brachytherapy treatment planning system for simple irradiation geometry with Ir-192 HDR source. Additionaly, Monte Carlo calculated data were also included in the brachytherapy study. There was observed effect of pH grade on dose-response curve parameters (slope of linear fit, background response, linear range and maximum measurable dose). In general, the lower pH grade the higher sensitivity. Another positive effect of decreased pH grade is significantly higher maximum measurable dose. Maximum melting temperature of a gel was observed with pH grade between 3.5 and 4. For both higher and lower pH grades the melting temperature was lower. Using pH modified polymer-gel dosimeter simple brachytherapy dose distribution was measured and compared with calculated and Monte Carlo simulated data. There was observed strong dependence of dose-response relationship on pH grade of polymer-gel dosimeter resulting in significant improvement of dosimeter characteristics, namely sensitivity, applicable range of

  10. Study on the Ion Association in PVdF-based Gel Polymer Electrolyte

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Gel polymer electrolytes based on the poly (vinylidene fluoride) (PVdF) and the electrolyte of LiClO4 in propylene carbonate (PC) were prepared by the solution casting technique. The ionic conductivity of the gel electrolytes was concentration of lithium salt. Because of the strong coulombiq attractions, the dissolved salt ions might aggregate into ion pairs and multiple ion aggregates. The analysis of DSC and X-ray diffraction revealed that the ions association occurred at higher concentration of lithium salt.

  11. Preparation of a Star Network PEG-based Gel Polymer Electrolyte and Its Application to Electrochromic Devices

    Institute of Scientific and Technical Information of China (English)

    GONG Yong-Feng; FU Xiang-Kai; ZHANG Shu-Peng; JIANG Qing-Long

    2007-01-01

    A star network polymer with a pentaerythritol core linking four PEG-block polymeric arms was synthesized,and its corresponding gel polymer electrolyte based on lithium perchlorate and plasticizers EC/PC with the character being colorless and highly transparent has been also prepared. The polymer host was characterized and confirmed to be of a star network and an amorphous structure by FTIR, 1H NMR and XRD studies. The polymer host hold good mechanical properties for pentaerythritol cross-linking. Maximum ionic conductivity of the prepared electrolyte showed that the thermal stability was up to at least 150 ℃. The gel polymer electrolyte was further evaluated in electrochromic devices fabricated by transparent PET-ITO and electrochromically active viologen derivative films, and its excellent performance promised the usage of the gel polymer electrolyte as ionic conductor material in electrochrornic devices.

  12. Characterization of new polyacrylonitrile-co-bis[2-(2-methoxyethoxy)ethyl]itaconate based gel polymer electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Choi, B.K.; Kim, Y.W. [Dankook Univ., Seoul (Korea). Dept. of Applied Physics; Gong, M.S. [Dankook Univ., Seoul (Korea). Dept. of Chemistry; Ahn, S.H. [Battery Research Center, LG Chemical Ltd., Taejon (Korea)

    2001-07-01

    Since the gel polymer electrolytes based on polyacrylonitrile (PAN) host have not been sufficient to fulfil the requirements as a separator of current lithium polymer battery, a new polymer host copolymerized with PAN, polyacrylonitrile-co-bis[2-(2-methoxyethoxy)ethyl]itaconate (abbreviated as PANI), was synthesized in expectation of enhanced trapping ability of liquid electrolytes. Electrical, electrochemical, thermal and mechanical studies have been carried out on PAN and PANI blended gel polymer electrolytes, complexed with ethylene carbonate (EC) and {sup g}amma{sup -}butyrolactone (BL) containing LiClO{sub 4} salt. The addition of PANI as a host polymer in the PAN-based gel polymer electrolytes has beneficial effects such as higher ionic conductivity, better thermal and electrochemical stabilities and enhanced ability of trapping organic solvent, possibly due to ion chelating ability of itaconate unit, though it shows less mechanical rigidity caused by amorphization of the PAN matrix. (Author).

  13. Radiological characteristics of MRI-based VIP polymer gel under carbon beam irradiation

    Science.gov (United States)

    Maeyama, T.; Fukunishi, N.; Ishikawa, K. L.; Furuta, T.; Fukasaku, K.; Takagi, S.; Noda, S.; Himeno, R.; Fukuda, S.

    2015-02-01

    We study the radiological characteristics of VIP polymer gel dosimeters under carbon beam irradiation with energy of 135 and 290 AMeV. To evaluate dose response of VIP polymer gels, the transverse (or spin-spin) relaxation rate R2 of the dosimeters measured by magnetic resonance imaging (MRI) as a function of linear energy transfer (LET), rather than penetration depth, as is usually done in previous reports. LET is evaluated by use of the particle transport simulation code PHITS. Our results reveal that the dose response decreases with increasing dose-averaged LET and that the dose response-LET relation also varies with incident carbon beam energy. The latter can be explained by taking into account the contribution from fragmentation products.

  14. Studies of plastic crystal gel polymer electrolytes based on poly(vinylidene chloride-co-acrylonitrile)

    Science.gov (United States)

    Hambali, D.; Zainuddin, Z.; Supa'at, I.; Osman, Z.

    2016-02-01

    In this work, we have prepared systems of poly(vinylidene chloride-co-acrylonitrile) (PVdC-co-AN) based gel polymer electrolytes (GPEs) which are single plasticized-GPEs and double plasticized-GPEs. Both systems comprised plastic crystal succinonitrile SN to form plastic crystal gel polymer electrolyte (PGPE) films. The ionic conductivity of the PGPE films were analysed by means of a.c. impedance spectroscopy at room temperature as well as at the temperature range of 303 K to 353 K. The temperature dependence ionic conductivity was found to obey the VTF rule. To study the interactions among the constituents in the PGPEs, Fourier Transform Infrared Spectroscopy (FTIR) was carried out and hence, the complexation between them has also been confirmed.

  15. Contrast enhancement of magnetic resonance imaging (MRI) of polymer gel dosimeter by adding Platinum nano- particles

    International Nuclear Information System (INIS)

    In this research different concentrations of Platinum nanoparticles (Pt-NPs) embedded in PAGAT polymer gel and irradiated with Cobalt -60 (60Co). The OD of samples indicate significant dose enhancement caused by Pt-NPs. Different concentrations of Pt-NPs were investigated: 0.5×10−2,1×10−2 2×10−2 and 3×10−2 mg/l and these were presented the enhancement in OD by the factor of 11.56, 27.10, 15.84 and 10.07 respectively. As the mean energy of 60Co is 1.25 MeV and atomic number (Z) of Pt is 78, the predominant effect will be Compton effect and Photoelectric cannot occurred. This work studied the feasibility of using PAGAT polymer gel combined with Pt-NPs as a suitable tool to perform dosimetric investigation of nanoparticles application in radiotherapy as dosimeter and dose enhancer

  16. Effect of the exothermal polymerization reaction on polymer gel dosimetric measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sedaghat, Mahbod; Bujold, Rachel; Lepage, Martin, E-mail: mahbod.sedaghat@Usherbrooke.c

    2010-11-01

    Discrepancies in polymer gel dosimetric measurements have been observed between containers of different sizes receiving the same radiation dose. We hypothesized that these deviations are caused by a change in the rate of polymerization due to internal heat increase in the gel containers resulting from the exothermic polymerization of monomers. Here, we test this hypothesis in a polyacrylamide gel dosimeter by recording the temperature in glass phantoms of different sizes during and after irradiation. The dose response of the samples was determined with magnetic resonance imaging. The difference of R{sub 2} values along the depth of the containers was below {+-}1%. We discuss that this small difference can be attributed to variations in the rate of gelatin cooling during manufacture rather than to the measured heat increase during irradiation.

  17. An x-ray CT polymer gel dosimetry prototype: I. Remnant artefact removal.

    Science.gov (United States)

    Jirasek, A; Carrick, J; Hilts, M

    2012-05-21

    In this study a new x-ray CT polymer gel dosimetry (PGD) filtering technique is presented for the removal of (i) remnant ring and streak artefacts, and (ii) 'structured' noise in the form of minute, intrinsic gel density fluctuations. It is shown that the noise present within x-ray CT PGD images is not purely stochastic (pixel by pixel) in nature, but rather is 'structured', and hence purely stochastic-based noise-removal filters fail in removing this significant, unwanted noise component. The remnant artefact removal (RAR) technique is based on a class of signal stripping (i.e. baseline-estimation) algorithms typically used in the estimation of unwanted non-uniform baselines underlying spectral data. Here the traditional signal removal algorithm is recast, whereby the 'signal' that is removed is the structured noise and remnant artefacts, leaving the desired polymer gel dose distribution. The algorithm is extended to 2D and input parameters are optimized for PGD images. RAR filter results are tested on (i) synthetic images with measured gel background images added, in order to accurately represent actual noise present in PGD images, and (ii) PGD images of a three-field gel irradiation. RAR results are compared to a top-performing noise filter (adaptive mean, AM), used in previous x-ray CT PGD studies. It is shown that, in all cases, the RAR filter outperforms the AM filter, particularly in cases where either (i) a low-dose gel image has been acquired or (ii) the signal-to-noise ratio of the PG image is low, as in the case when a low number of image averages are acquired within a given experiment. Guidelines for the implementation of the RAR filter are given.

  18. Tubular array, dielectric, conductivity and electrochemical properties of biodegradable gel polymer electrolyte

    International Nuclear Information System (INIS)

    Highlights: • A new finding of tubular array of 10–20 μm in length and 1–2 μm in thickness of gel polymer electrolyte (GPE) having 2.2 × 10−3 S cm−1 conductivity is reported. • Thermal and electrochemical characterizations of GPEs show good interaction among the polymer, plasticizer and salt. • GPE based supercapacitor demonstrates high capacitance of 186 F g−1. • Low temperature studies did not influence much on capacitance values obtained from AC impedance studies. • Charge–discharge exhibits high capacity with excellent cyclic stability and energy density. -- Abstract: A supercapacitor based on a biodegradable gel polymer electrolyte (GPE) has been fabricated using guar gum (GG) as the polymer matrix, LiClO4 as the doping salt and glycerol as the plasticizer. The scanning electron microscopy (SEM) images of the gel polymer showed an unusual tubular array type surface morphology. FTIR, DSC and TGA results of the GPE indicated good interaction between the components used. Highest ionic conductivity and lowest activation energy values were 2.2 × 10−3 S cm−1 and 0.18 eV, respectively. Dielectric studies revealed ionic behavior and good capacitance with varying frequency of the GPE system. The fabricated supercapacitor showed a maximum specific capacitance value of 186 F g−1 using cyclic voltammetry. Variation of temperature from 273 K to 293 K did not significantly influence the capacitance values obtained from AC impedance studies. Galvanostatic charge–discharge study of supercapacitor indicated that the device has good stability, high energy density and power density

  19. Development of Polymer Gel Systems to Improve Volumetric Sweep and Reduce Producing Water/Oil Ratios

    Energy Technology Data Exchange (ETDEWEB)

    G. Paul Willhite; Stan McCool; Don W. Green; Min Cheng; Feiyan Chen

    2005-12-31

    Gelled polymer treatments are applied to oil reservoirs to increase oil production and to reduce water production by altering the fluid movement within the reservoir. This report describes the results of a 42-month research program that focused on the understanding of gelation chemistry and the fundamental mechanisms that alter the flows of oil and water in reservoir rocks after a gel treatment. Work was conducted on a widely applied system in the field, the partially hydrolyzed polyacrylamide-chromium acetate gel. Gelation occurs by network formation through the crosslinking of polyacrylamide molecules as a result of reaction with chromium acetate. Pre-gel aggregates form and grow as reactions between chromium acetate and polyacrylamide proceed. A rate equation that describes the reaction between chromium acetate and polymer molecules was regressed from experimental data. A mathematical model that describes the crosslinking reaction between two polymer molecules as a function of time was derived. The model was based on probability concepts and provides molecular-weight averages and molecular-weight distributions of the pre-gel aggregates as a function of time and initial system conditions. Average molecular weights of pre-gel aggregates were measured as a function of time and were comparable to model simulations. Experimental methods to determine molecular weight distributions of pre-gel aggregates were unsuccessful. Dissolution of carbonate minerals during the injection of gelants causes the pH of the gelant to increase. Chromium precipitates from solution at the higher pH values robbing the gelant of crosslinker. Experimental data on the transport of chromium acetate solutions through dolomite cores were obtained. A mathematical model that describes the transport of brine and chromium acetate solutions through rocks containing carbonate minerals was used to simulate the experimental results and data from literature. Gel treatments usually reduce the permeability

  20. Effect of polymer aggregation on the open circuit voltage in organic photovoltaic cells: aggregation-induced conjugated polymer gel and its application for preventing open circuit voltage drop.

    Science.gov (United States)

    Kim, Bong-Gi; Jeong, Eun Jeong; Park, Hui Joon; Bilby, David; Guo, L Jay; Kim, Jinsang

    2011-03-01

    To investigate the structure-dependent aggregation behavior of conjugated polymers and the effect of aggregation on the device performance of conjugated polymer photovoltaic cells, new conjugated polymers (PVTT and CN-PVTT) having the same regioregularity but different intermolecular packing were prepared and characterized by means of UV-vis spectroscopy and atomic force microscopy (AFM). Photovoltaic devices were prepared with these polymers under different polymer-aggregate conditions. Polymer aggregation induced by thermal annealing increases the short circuit current but provides no advantage in the overall power conversion efficiency because of a decrease in the open circuit voltage. The device fabricated from a pre-aggregated polymer suspension, acquired from ultrasonic agitation of a conjugated polymer gel, showed enhanced performance because of better phase separation and reduced recombination between polymer/PCBM.

  1. Deformation of redox-active polymer gel based on polysiloxane backbone and bis(benzodithiolyl)bithienyl scaffold.

    Science.gov (United States)

    Ohtake, Toshihiro; Tanaka, Hideki; Matsumoto, Tetsuro; Ohta, Akira; Kimura, Mutsumi

    2014-12-01

    Redox-active polymer gels consisting of polysiloxane backbone and bis(benzodithiolyl)bithienyl units have been designed and synthesized. The bis(benzodithiolyl)bithienyl units, which undergo interconversion between cyclic form and opened dicationic form, have been incorporated into polysiloxane backbone via hydrosilylation of vinyl-terminated bis(benzodithiolyl)bithienyl derivative and poly(methylhydrosiloxane) (PMHS) or poly(dimethylsiloxane-co-hydrogenmethylsiloxane) (PDMS-co-PMHS), resulting in polymer gels cross-linked with bis(benzodithiolyl)bithienyl units. After the incorporation of M1 into polysiloxane backbone, these polymer gels (P1 and P2) also exhibit redox responses associated with the electrochemical interconversion of the bis(benzodithiolyl)bithienyl moieties. The polymer gels show swelling behavior upon chemical oxidization, and bending behavior has been observed for the polymer gel immobilized poly(vinylidene difluoride) (PVdF) film. These results provide a useful perspective for fabricating redox-triggered polymer gel actuators based on the conformational change of the functional molecular unit. PMID:25400032

  2. The application of polymer gel dosimeters to dosimetry for targeted radionuclide therapy

    International Nuclear Information System (INIS)

    There is a lack of standardized methodology to perform dose calculations for targeted radionuclide therapy and at present no method exists to objectively evaluate the various approaches employed. The aim of the work described here was to investigate the practicality and accuracy of calibrating polymer gel dosimeters such that dose measurements resulting from complex activity distributions can be verified. Twelve vials of the polymer gel dosimeter, 'MAGIC', were uniformly mixed with varying concentrations of P-32 such that absorbed doses ranged from 0 to 30 Gy after a period of 360 h before being imaged on a magnetic resonance scanner. In addition, nine vials were prepared and irradiated using an external 6 MV x-ray beam. Magnetic resonance transverse relaxation time, T2, maps were obtained using a multi-echo spin echo sequence and converted to R2 maps (where T2 = 1/R2). Absorbed doses for P-32 irradiated gel were calculated according to the medical internal radiation dose schema using EGSnrc Monte Carlo simulations. Here the energy deposited in cylinders representing the irradiated vials was scored. A relationship between dose and R2 was determined. Effects from oxygen contamination were present in the internally irradiated vials. An increase in O2 sensitivity over those gels irradiated externally was thought to be a result of the longer irradiation period. However, below the region of contamination dose response appeared homogenous. Due do a drop-off of dose at the periphery of the internally irradiated vials, magnetic resonance ringing artefacts were observed. The ringing did not greatly affect the accuracy of calibration, which was comparable for both methods. The largest errors in calculated dose originated from the initial activity measurements, and were approximately 10%. Measured R2 values ranged from 5-35 s-1 with an average standard deviation of 1%. A clear relationship between R2 and dose was observed, with up to 40% increased sensitivity for internally

  3. The application of polymer gel dosimeters to dosimetry for targeted radionuclide therapy

    Energy Technology Data Exchange (ETDEWEB)

    Gear, J I [Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, Surrey (United Kingdom); Flux, G D [Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, Surrey (United Kingdom); Charles-Edwards, E [Clinical Magnetic Research Group, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, Surrey (United Kingdom); Partridge, M [Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, Surrey (United Kingdom); Cook, G [Department of Nuclear Medicine, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, Surrey (United Kingdom); Ott, R J [Joint Department of Physics, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, Surrey (United Kingdom)

    2006-07-21

    There is a lack of standardized methodology to perform dose calculations for targeted radionuclide therapy and at present no method exists to objectively evaluate the various approaches employed. The aim of the work described here was to investigate the practicality and accuracy of calibrating polymer gel dosimeters such that dose measurements resulting from complex activity distributions can be verified. Twelve vials of the polymer gel dosimeter, 'MAGIC', were uniformly mixed with varying concentrations of P-32 such that absorbed doses ranged from 0 to 30 Gy after a period of 360 h before being imaged on a magnetic resonance scanner. In addition, nine vials were prepared and irradiated using an external 6 MV x-ray beam. Magnetic resonance transverse relaxation time, T{sub 2}, maps were obtained using a multi-echo spin echo sequence and converted to R{sub 2} maps (where T{sub 2} = 1/R{sub 2}). Absorbed doses for P-32 irradiated gel were calculated according to the medical internal radiation dose schema using EGSnrc Monte Carlo simulations. Here the energy deposited in cylinders representing the irradiated vials was scored. A relationship between dose and R{sub 2} was determined. Effects from oxygen contamination were present in the internally irradiated vials. An increase in O{sub 2} sensitivity over those gels irradiated externally was thought to be a result of the longer irradiation period. However, below the region of contamination dose response appeared homogenous. Due do a drop-off of dose at the periphery of the internally irradiated vials, magnetic resonance ringing artefacts were observed. The ringing did not greatly affect the accuracy of calibration, which was comparable for both methods. The largest errors in calculated dose originated from the initial activity measurements, and were approximately 10%. Measured R{sub 2} values ranged from 5-35 s{sup -1} with an average standard deviation of 1%. A clear relationship between R{sub 2} and dose was

  4. Thermostable gel polymer electrolyte based on succinonitrile and ionic liquid for high-performance solid-state supercapacitors

    Science.gov (United States)

    Pandey, Gaind P.; Liu, Tao; Hancock, Cody; Li, Yonghui; Sun, Xiuzhi Susan; Li, Jun

    2016-10-01

    A flexible, free-standing, thermostable gel polymer electrolyte based on plastic crystalline succinonitrile (SN) and ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF4) entrapped in copolymer poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) is prepared and optimized for application in solvent-free solid-state supercapacitors. The synthesized gel polymer electrolyte exhibits a high ionic conductivity over a wide temperature range (from ∼5 × 10-4 S cm-1 at -30 °C up to ∼1.5 × 10-2 S cm-1 at 80 °C) with good electrochemical stability window (-2.9 to 2.5 V). Thermal studies confirm that the SN containing gel polymer electrolyte remains stable in the same gel phase over a wide temperature range from -30 to 90 °C. The electric double layer capacitors (EDLCs) have been fabricated using activated carbon as active materials and new gel polymer electrolytes. Electrochemical performance of the EDLCs is assessed through cyclic voltammetry, galvanostatic charge-discharge cycling and impedance spectroscopy. The EDLC cells with the proper SN-containing gel polymer electrolyte has been found to give high specific capacitance 176 F g-1 at 0.18 A g-1 and 138 F g-1 at 8 A g-1. These solid-state EDLC cells show good cycling stability and the capability to retain ∼80% of the initial capacitance after 10,000 cycles.

  5. Structure and Hydrogen Bonding of Water in Polyacrylate Gels: Effects of Polymer Hydrophilicity and Water Concentration.

    Science.gov (United States)

    Mani, Sriramvignesh; Khabaz, Fardin; Godbole, Rutvik V; Hedden, Ronald C; Khare, Rajesh

    2015-12-10

    The ability to tune the hydrophilicity of polyacrylate copolymers by altering their composition makes these materials attractive candidates for membranes used to separate alcohol-water mixtures. The separation behavior of these polyacrylate membranes is governed by a complex interplay of factors such as water and alcohol concentrations, water structure in the membrane, polymer hydrophilicity, and temperature. We use molecular dynamics simulations to investigate the effect of polymer hydrophilicity and water concentration on the structure and dynamics of water molecules in the polymer matrix. Samples of poly(n-butyl acrylate) (PBA), poly(2-hydroxyethyl acrylate) (PHEA), and a 50/50 copolymer of BA and HEA were synthesized in laboratory, and their properties were measured. Model structures of these systems were validated by comparing the simulated values of their volumetric properties with the experimental values. Molecular simulations of polyacrylate gels swollen in water and ethanol mixtures showed that water exhibits very different affinities toward the different (carbonyl, alkoxy, and hydroxyl) functional groups of the polymers. Water molecules are well dispersed in the system at low concentrations and predominantly form hydrogen bonds with the polymer. However, water forms large clusters at high concentrations along with the predominant formation of water-water hydrogen bonds and the acceleration of hydrogen bond dynamics. PMID:26514915

  6. 凝胶聚合物电解质的研究进展%Research Progress of Gel Polymer Electrolytes

    Institute of Scientific and Technical Information of China (English)

    万玉荣; 乔庆东; 李琪

    2015-01-01

    Several kinds of polymer materials used as the matrix of gel polymer electrolytes were introduced, such as polyethylene oxide (PEO), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), poly (vinylidene fluoride) (PVDF). Currently, research on gel polymer electrolyte is still in the primary stage. And there are many problems in the study of gel polymer electrolytes. In this article, modification methods of gel polymer electrolytes were discussed, such as crosslinking, copolymerization, blending or adding fillers, and so on. The application prospect of gel polymer electrolytes was analyzed.%介绍了几种聚合物高分子材料,常以其作为凝胶聚合物电解质基体。如聚氧化乙烯(PEO)、聚丙烯腈(PAN)、聚甲基丙烯酸甲酯(PMMA)、聚偏氟乙烯(PVDF)。对于凝胶聚合物电解质的研究,目前仍处于初级阶段,还存在许多问题。本文探讨了凝胶聚合物电解质的改性方法,主要有交联、共聚、共混或添加填料等,并展望了凝胶聚合物电解质的应用前景。

  7. Theory of DNA electrophoresis in physical gels and entangled polymer solutions

    Science.gov (United States)

    Duke, Thomas; Viovy, Jean Louis

    1994-03-01

    A scaling theory is presented for the electrophoretic mobility of DNA in sieving media that form dynamically evolving meshworks, such as physical gels and solutions of entangled polymers. In such media, the topological constraints on the DNA's motion are perpetually changing as cross links break and rejoin or as the polymers diffuse. It is shown that if the rate of constraint release falls within a certain range (which depends on the field strength), fractionation can be extended to higher molecular weights than would be feasible using a permanent gel of equivalent pore size. This improvement is a consequence of the disruptive effect that constraint release has on the mechanism of molecular orientation. Numerical simulations support the predictions of the theory. The possibility of realizing such a system in practice, with the aim of improving on current electrophoresis methods, is commented upon. It is suggested that semidilute polymer solutions may be a versatile medium for the rapid separation of long single-stranded DNA molecules, and the particular quality of solution required is identified.

  8. Insulin release from islets of Langerhans entrapped in a poly(N-isopropylacrylamide-co-acrylic acid) polymer gel.

    Science.gov (United States)

    Vernon, B; Kim, S W; Bae, Y H

    1999-01-01

    A copolymer of N-isopropylacrylamide (98 mol% in feed) and acrylic acid, poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAAm-co-AAc)), was prepared by free radical polymerization for development of a thermally reversible polymer to entrap islets of Langerhans for a refillable biohybrid artificial pancreas. A 5 wt% solution of the polymer in Hanks' balanced salt solution forms a gel at 37 degrees C that exhibits no syneresis. Diffusion of fluorescein isothiocyanate (FITC) dextrans having molecular weights of 4400 and 70000 were used to evaluate mass transport in the gel at 37 degrees C. Insulin secretion from islets in the polymer gel was also investigated in both static and dynamic systems. The polymer gel exhibited excellent diffusion of FITC dextran 4400 and FITC dextran 70000 with diffusion ratios, D/D0 (ratio of diffusion in the gel to diffusion in water), of 0.20+/-0.04 and 0.35+/-0.17, respectively. Human islets entrapped in the polymer gel showed prolonged insulin secretion in response to basal (5.5 mM) glucose concentration compared to free human islets. Rat islets showed prolonged insulin secretion in response to high (16.5 mM) glucose concentrations compared to free rat islets. Rat islets in the polymer gel maintained insulin secretion in response to the higher glucose concentration for over 26 days. Rat islets entrapped by the polymer also released higher quantities of insulin more rapidly in response to changes in concentrations of glucose and other stimulants than rat islets entrapped in an alginate control. These results suggest that this material would provide adequate diffusion for rapid insulin release in an application as a synthetic extracellular matrix for a biohybrid artificial pancreas.

  9. 4.4 V lithium-ion polymer batteries with a chemical stable gel electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Takeru; Hara, Tomitaro; Akashi, Hiroyuki [Sony Corporation, Energy Business Group, R and D Division, 1-1 Aza, Shimosugishita, Takakura, Hiwada-machi, Koriyama-shi, Fukushima 963-0531 (Japan); Segawa, Ken; Honda, Kazuo [Sony Energy Device Corporation, PB Technology Center, 1-1 Aza, Shimosugishita, Takakura, Hiwada-machi, Koriyama-shi, Fukushima 963-0531 (Japan)

    2007-12-06

    We tested 4.2 V Li-ion polymer batteries (LIPB) with physical gel electrolyte, poly(vinylidene fluoride) (PVDF), 4.4 V LIPB and 4.4 V Li-ion batteries (LIB) with a liquid electrolyte. The discharge capacity of the 4.4 V LIPB reached 520 Wh l{sup -1} which was 9% higher than that of the 4.2 V LIPB. The 4.4 V LIPB had a high capacity retention ratio of 91.4% at 3 C because of the excellent ion conductivity of the PVDF gel. The capacity retention ratio of the 4.4 V LIPB was 82% after 500 cycles, which is comparable to those of some commercial LIBs. The 4.4 V LIPB retained its original thickness even after many cycles and after being stored at 90 C, whereas the 4.4 V LIB swelled by over 20%. Peaks in the FT-IR spectrum of the discolored separator in the 4.4 V LIB after storage were assigned to C=C double bonds, suggesting that the separator in direct contact with the 4.4 V cathode had been oxidized. The PVDF gel electrolyte not only had a high ionic conductivity but also completely suppressed oxidation. The 4.4 V LIPB with PVDF gel electrolyte has properties suitable for practical cells, namely, high energy density, high permanence and it is safe to use. (author)

  10. A pH-responsive supramolecular polymer gel as an enteric elastomer for use in gastric devices.

    Science.gov (United States)

    Zhang, Shiyi; Bellinger, Andrew M; Glettig, Dean L; Barman, Ross; Lee, Young-Ah Lucy; Zhu, Jiahua; Cleveland, Cody; Montgomery, Veronica A; Gu, Li; Nash, Landon D; Maitland, Duncan J; Langer, Robert; Traverso, Giovanni

    2015-10-01

    Devices resident in the stomach-used for a variety of clinical applications including nutritional modulation for bariatrics, ingestible electronics for diagnosis and monitoring, and gastric-retentive dosage forms for prolonged drug delivery-typically incorporate elastic polymers to compress the devices during delivery through the oesophagus and other narrow orifices in the digestive system. However, in the event of accidental device fracture or migration, the non-degradable nature of these materials risks intestinal obstruction. Here, we show that an elastic, pH-responsive supramolecular gel remains stable and elastic in the acidic environment of the stomach but can be dissolved in the neutral-pH environment of the small and large intestines. In a large animal model, prototype devices with these materials as the key component demonstrated prolonged gastric retention and safe passage. These enteric elastomers should increase the safety profile for a wide range of gastric-retentive devices.

  11. Superspreading on Immersed Gel Surfaces for the Confined Synthesis of Thin Polymer Films.

    Science.gov (United States)

    Zhang, Pengchao; Zhang, Feilong; Zhao, Chuangqi; Wang, Shutao; Liu, Mingjie; Jiang, Lei

    2016-03-01

    Liquid spreading is of significant interest in science and technology. Although surface topography engineering and liquid surface-tension regulating can facilitate spreading, the spreading layers in these strategies are inevitably inhomogeneous or contaminated with surfactants. Herein, we show a general strategy to realize the superspreading of liquids on mutually soluble gel surfaces. The cooperation of the hydraulic pressure under liquid phase and liquid-like property of gel surfaces can dramatically eliminate the local pinning effect and enhance the advancement of three-phase contact line, thus forming stable and homogeneous superspreading liquid layers. Such liquid layers can be converted into various functional thin polymer films with controlled thicknesses (nm- to µm-scale) through one-step polymerization of the reactants. Our strategy offers opportunities for large-scale synthesis of versatile functional thin films for various applications. PMID:26880685

  12. Small field dose delivery evaluations using cone beam optical computed tomography-based polymer gel dosimetry

    Directory of Open Access Journals (Sweden)

    Timothy Olding

    2011-01-01

    Full Text Available This paper explores the combination of cone beam optical computed tomography with an N-isopropylacrylamide (NIPAM-based polymer gel dosimeter for three-dimensional dose imaging of small field deliveries. Initial investigations indicate that cone beam optical imaging of polymer gels is complicated by scattered stray light perturbation. This can lead to significant dosimetry failures in comparison to dose readout by magnetic resonance imaging (MRI. For example, only 60% of the voxels from an optical CT dose readout of a 1 l dosimeter passed a two-dimensional Low′s gamma test (at a 3%, 3 mm criteria, relative to a treatment plan for a well-characterized pencil beam delivery. When the same dosimeter was probed by MRI, a 93% pass rate was observed. The optical dose measurement was improved after modifications to the dosimeter preparation, matching its performance with the imaging capabilities of the scanner. With the new dosimeter preparation, 99.7% of the optical CT voxels passed a Low′s gamma test at the 3%, 3 mm criteria and 92.7% at a 2%, 2 mm criteria. The fitted interjar dose responses of a small sample set of modified dosimeters prepared (a from the same gel batch and (b from different gel batches prepared on the same day were found to be in agreement to within 3.6% and 3.8%, respectively, over the full dose range. Without drawing any statistical conclusions, this experiment gives a preliminary indication that intrabatch or interbatch NIPAM dosimeters prepared on the same day should be suitable for dose sensitivity calibration.

  13. Nanostructured electrodes and gel-polymer electrolyte for an improved Li-ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Bodoardo, S.; Bongiovanni, R.; Gerbaldi, C.; Meligrana, G.; Nair, J. [Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino (Italy); Mulas, G. [Dipartimento di Chimica, Universita di Sassari (Italy); Penazzi, N.

    2009-06-15

    The present communication deals with the results obtained by the electrochemistry research group at the Politecnico di Torino in Italy in the field of materials for Li-ion cells. Cathode (LiFePO{sub 4}/C powder), anode (Ni{sub 3}Sn{sub 4}-C alloy) and electrolyte (gel-polymer membrane) cell components have been prepared with the aim of obtaining, beyond high performance, cheap materials from easily disposable reagents via simple and reliable preparations. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  14. Sensitivity calibration procedures in optical-CT scanning of BANG 3 polymer gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Y.; Wuu, Cheng-Shie; Maryanski, Marek J. [Department of Radiation Oncology, Columbia University, New York, New York 10032 (United States); Department of Radiation Oncology, Columbia University, New York, New York 10032 and MGS Research Inc., Madison, Connecticut 06443 (United States)

    2010-02-15

    The dose response of the BANG 3 polymer gel dosimeter (MGS Research Inc., Madison, CT) was studied using the OCTOPUS laser CT scanner (MGS Research Inc., Madison, CT). Six 17 cm diameter and 12 cm high Barex cylinders, and 18 small glass vials were used to house the gel. The gel phantoms were irradiated with 6 and 10 MV photons, as well as 12 and 16 MeV electrons using a Varian Clinac 2100EX. Three calibration methods were used to obtain the dose response curves: (a) Optical density measurements on the 18 glass vials irradiated with graded doses from 0 to 4 Gy using 6 or 10 MV large field irradiations; (b) optical-CT scanning of Barex cylinders irradiated with graded doses (0.5, 1, 1.5, and 2 Gy) from four adjacent 4x4 cm{sup 2} photon fields or 6x6 cm{sup 2} electron fields; and (c) percent depth dose (PDD) comparison of optical-CT scans with ion chamber measurements for 6x6 cm{sup 2}, 12 and 16 MeV electron fields. The dose response of the BANG 3 gel was found to be linear and energy independent within the uncertainties of the experimental methods (about 3%). The slopes of the linearly fitted dose response curves (dose sensitivities) from the four field irradiations (0.0752{+-}3%, 0.0756{+-}3%, 0.0767{+-}3%, and 0.0759{+-}3% cm{sup -1} Gy{sup -1}) and the PDD matching methods (0.0768{+-}3% and 0.0761{+-}3% cm{sup -1} Gy{sup -1}) agree within 2.2%, indicating a good reproducibility of the gel dose response within phantoms of the same geometry. The dose sensitivities from the glass vial approach are different from those of the cylindrical Barex phantoms by more than 30%, owing probably to the difference in temperature inside the two types of phantoms during gel formation and irradiation, and possible oxygen contamination of the glass vial walls. The dose response curve obtained from the PDD matching approach with 16 MeV electron field was used to calibrate the gel phantom irradiated with the 12 MeV, 6x6 cm{sup 2} electron field. Three-dimensional dose distributions

  15. In vitro permeation studies of phenolics from horse chestnut seed gels prepared with different polyacrylic acid polymer derivatives

    Directory of Open Access Journals (Sweden)

    Zelbienė Eglė

    2015-06-01

    Full Text Available The aim of this study was to investigate the effects of polyacrylic acid polymers (Ultrez 10, Ultrez 20, Carbopol 980, and Carbopol 940 on the viscosity and the in vitro permeation of phenolic compounds from the gel prepared from natural horse chestnut seed extract. Experiments were performed in the presence and in the absence of peppermint oil (Mentha piperita. Our results showed that peppermint oil decreased the viscosity of the gels and permeation of phenolic compounds from all gel samples. Results show that the highest content of phenolic compounds (1.758 μg cm-2 permeated in vitro from gel based on Carbopol Ultrez 20 without peppermint oil added (p < 0.05 vs. other tested polymers.

  16. Cross-linked Composite Gel Polymer Electrolyte using Mesoporous Methacrylate-Functionalized SiO2 Nanoparticles for Lithium-Ion Polymer Batteries

    Science.gov (United States)

    Shin, Won-Kyung; Cho, Jinhyun; Kannan, Aravindaraj G.; Lee, Yoon-Sung; Kim, Dong-Won

    2016-05-01

    Liquid electrolytes composed of lithium salt in a mixture of organic solvents have been widely used for lithium-ion batteries. However, the high flammability of the organic solvents can lead to thermal runaway and explosions if the system is accidentally subjected to a short circuit or experiences local overheating. In this work, a cross-linked composite gel polymer electrolyte was prepared and applied to lithium-ion polymer cells as a safer and more reliable electrolyte. Mesoporous SiO2 nanoparticles containing reactive methacrylate groups as cross-linking sites were synthesized and dispersed into the fibrous polyacrylonitrile membrane. They directly reacted with gel electrolyte precursors containing tri(ethylene glycol) diacrylate, resulting in the formation of a cross-linked composite gel polymer electrolyte with high ionic conductivity and favorable interfacial characteristics. The mesoporous SiO2 particles also served as HF scavengers to reduce the HF content in the electrolyte at high temperature. As a result, the cycling performance of the lithium-ion polymer cells with cross-linked composite gel polymer electrolytes employing methacrylate-functionalized mesoporous SiO2 nanoparticles was remarkably improved at elevated temperatures.

  17. Cross-linked Composite Gel Polymer Electrolyte using Mesoporous Methacrylate-Functionalized SiO2 Nanoparticles for Lithium-Ion Polymer Batteries.

    Science.gov (United States)

    Shin, Won-Kyung; Cho, Jinhyun; Kannan, Aravindaraj G; Lee, Yoon-Sung; Kim, Dong-Won

    2016-01-01

    Liquid electrolytes composed of lithium salt in a mixture of organic solvents have been widely used for lithium-ion batteries. However, the high flammability of the organic solvents can lead to thermal runaway and explosions if the system is accidentally subjected to a short circuit or experiences local overheating. In this work, a cross-linked composite gel polymer electrolyte was prepared and applied to lithium-ion polymer cells as a safer and more reliable electrolyte. Mesoporous SiO2 nanoparticles containing reactive methacrylate groups as cross-linking sites were synthesized and dispersed into the fibrous polyacrylonitrile membrane. They directly reacted with gel electrolyte precursors containing tri(ethylene glycol) diacrylate, resulting in the formation of a cross-linked composite gel polymer electrolyte with high ionic conductivity and favorable interfacial characteristics. The mesoporous SiO2 particles also served as HF scavengers to reduce the HF content in the electrolyte at high temperature. As a result, the cycling performance of the lithium-ion polymer cells with cross-linked composite gel polymer electrolytes employing methacrylate-functionalized mesoporous SiO2 nanoparticles was remarkably improved at elevated temperatures. PMID:27189842

  18. The effect of multifunctional polymer-based gels on wound healing in full thickness bacteria-contaminated mouse models

    OpenAIRE

    Yates, Cecelia Christina; Whaley, Diana; Babu, Ranjith; Zhang, Jianying; Krishna, Priya; Beckman, Eric; Pasculle, A. William; Wells, Alan

    2007-01-01

    We determined whether a two part space-conforming polyethyleneglycol/dopa polymer-based gel promoted healing of contaminated wounds in mice. This silver-catalysed gel was previously developed to be broadly microbiocidal in vitro while being biocompatible with human wound cell functioning. Full-thickness wounds were created on the backs of mice. The wounds were inoculated with 104 CFU of each of four common skin wound contaminants, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter b...

  19. Study of the relative dose-response of BANG-3[reg] polymer gel dosimeters in epithermal neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Uusi-Simola, J [Department of Radiology, Helsinki University Central Hospital, FIN-00029 HUS (Finland); Savolainen, S [Department of Radiology, Helsinki University Central Hospital, FIN-00029 HUS (Finland); Kangasmaeki, A [Department of Radiology, Helsinki University Central Hospital, FIN-00029 HUS (Finland); Heikkinen, S [Department of Laboratory Diagnostics, Helsinki University Central Hospital, FIN-00029 HUS (Finland); Perkioe, J [Department of Radiology, Helsinki University Central Hospital, FIN-00029 HUS (Finland); Ramadan, U Abo [Department of Laboratory Diagnostics, Helsinki University Central Hospital, FIN-00029 HUS (Finland); Seppaelae, T [Department of Oncology, Helsinki University Central Hospital, FIN-00029 HUS (Finland); Karila, J [Department of Oncology, Helsinki University Central Hospital, FIN-00029 HUS (Finland); Seren, T [VTT Processes, Technical Research Centre of Finland, FIN-02044 VTT, Finland (Finland); Kotiluoto, P [VTT Processes, Technical Research Centre of Finland, FIN-02044 VTT, Finland (Finland); Sorvari, P [Department of Laboratory Diagnostics, Helsinki University Central Hospital, FIN-00029 HUS (Finland); Auterinen, I [VTT Processes, Technical Research Centre of Finland, FIN-02044 VTT, Finland (Finland)

    2003-09-07

    Polymer gels have been reported as a new, potential tool for dosimetry in mixed neutron-gamma radiation fields. In this work, BANG-3 (MGS Research Inc.) gel vials from three production batches were irradiated with 6 MV photons of a Varian Clinac 2100 C linear accelerator and with the epithermal neutron beam of the Finnish boron neutron capture therapy (BNCT) facility at the FiR 1 nuclear reactor. The gel is tissue equivalent in main elemental composition and density and its T2 relaxation time is dependent on the absorbed dose. The T2 relaxation time map of the irradiated gel vials was measured with a 1.5 T magnetic resonance (MR) scanner using spin echo sequence. The absorbed doses of neutron irradiation were calculated using DORT computer code, and the accuracy of the calculational model was verified by measuring gamma ray dose rate with thermoluminescent dosimeters and {sup 55}Mn(n,{gamma}) activation reaction rate with activation detectors. The response of the BANG-3 gel dosimeter for total absorbed dose in the neutron irradiation was linear, and the magnitude of the response relative to the response in the photon irradiation was observed to vary between different gel batches. The results support the potential of polymer gels in BNCT dosimetry, especially for the verification of two- or three-dimensional dose distributions.

  20. 3D dosimetry for complex stereotactic radiosurgery using a tomographic optical density scanner and BANG polymer gels

    International Nuclear Information System (INIS)

    Purpose: Radiation sensitive tissue equivalent BANG polymer gels (MGS Research, Inc., Guilford, CT) have been developed for three dimensional verification of complex radiotherapy treatment plans. This study evaluated the performance of a prototype optical density scanner in verification of a complex radiosurgery treatment plan using linear accelerator based radiosurgery and BANG polymer gel dosimeters. Materials and Methods: BANG polymer gel dosimeters were treated with stereotactic radiosurgery using 6MV photons to single isocenters and to a 3 isocenter radiosurgery plan. Appropriate controls for evaluating the linearity of dose response were irradiated using a water bath and 6MV photons. Two separate methods for imaging the radiation-induced polymerization in the gel were used. The first method, MRI imaging, used the spatial distribution of the NMR transverse relaxation rates (R2) of the water protons in the gel to create a 3D dose map. In the second, a prototype optical density scanner was used to reconstruct a 3D dose distribution from multiple planar images of the gel which were generated using a filtered back-projection algorithm and measurements of optical transmission. Results: Data obtained from MRI imaging and the images generated by the optical scanner were compared with the plan with excellent results. Very close agreement between all three data sets was demonstrated. The BANG polymer gels demonstrated an excellent linearity of response and a very large (∼20 Gray) dynamic range. Conclusion: The ability to permanently record (and interrogate at a later time) integrated 3D dose distributions will be valuable in assessing complex external beam treatment plans such as radiosurgical treatment plans as well as in commissioning and periodic checking of dynamic wedges, multileaf collimators, etc. used for conventionally fractionated conformal radiotherapy. The linearity of response and wide dynamic range are important in the evaluation of radiosurgical

  1. Synthesis of nano-bound microsphere Co3O4 by simple polymer-assisted sol–gel technique

    International Nuclear Information System (INIS)

    Nano-bound Co3O4 microspheres and molten Co3O4 microspheres were synthesized for the first time by a simple polymer (poly-(vinylpyrrolidone))-assisted sol–gel and sol–gel technique, respectively. Thermal decomposition of the precursor samples of both polymer-assisted sol–gel and sol–gel technique were studied by thermogravimetric analysis. In both techniques, the material was calcined at different temperatures for the formation of phase pure Co3O4. X-ray diffraction confirmed the formation of phase pure cubic spinel structured Co3O4 at 400 and 500 °C for the polymer-assisted sol–gel and sol–gel technique, respectively. Fourier transform infrared spectroscopy revealed the vibrational assignments of functional groups associated with the cubic spinel structure of Co3O4. Scanning electron microscopy of all samples showed clear microsphere sizes ranging from 1 to 4 μm. Both techniques allowed the formation of spherical-shaped microspheres by a simple process. Nano-bound microspheres were observed from the polymer-assisted sol–gel technique because the decomposition of PVP at 400 °C is the main reason for the formation of nano-bound microspheres. The nanoparticle size of the nano-bound microsphere measured by transmission electron microscopy was ∼40 nm. Therefore, PVP is an essential compound for the formation of nano-bound microspheres. This very simple and inexpensive technique is suitable for the formation of spherical-shaped microspheres.

  2. Effect of thiolated polymers to textural and mucoadhesive properties of vaginal gel formulations prepared with polycarbophil and chitosan.

    Science.gov (United States)

    Cevher, Erdal; Sensoy, Demet; Taha, Mohamed A M; Araman, Ahmet

    2008-01-01

    The aim of this study was to design and evaluate of mucoadhesive gel formulations for the vaginal application of clomiphene citrate (CLM) for local treatment of human papilloma virus (HPV) infections. Chitosan (CHI) and polycarbophil (PC) were covalently modified using the thioglycolic acid and L-cysteine, respectively. The formation of thiol conjugates of chitosan (CHI-TG) and polycarbophil (PC-CYS) were confirmed by FT-IR analysis and PC-CYS and CHI-TG were found to have 148.42 +/- 4.16 and 41.17 +/- 2.34 micromol of thiol groups per gram of polymer, respectively. One percent CLM gels were prepared by combination of various concentrations of PC and CHI with thiolated conjugates of these polymers. Hardness, compressibility, elasticity, adhesiveness and cohesiveness of the gels were measured by Texture profile analysis and the vaginal mucoadhesion was investigated by mucoadhesion test. The increasing in the amount of the thiol conjugates was found to enhance the elasticity, cohesiveness, adhesiveness and mucoadhesion of the gel formulations but not their hardness and compressibility when compared to gels prepared using their respective parent formulations. Slower release rate of CLM from gels was achieved when the polymer concentrations were increased in the gel formulations. PC and its thiol conjugate were found to prolong the release of CLM longer than 70 h unlike gel formulations prepared using CHI and its thiol conjugate which were able to release CLM up to 12 h. Stability of CLM was preserved during the 3 month stability analysis under controlled room temperature and accelerated conditions.

  3. Ionic transport and electrochemical stability of PVDF-HFP based gel polymer electrolytes

    Science.gov (United States)

    Rosdi, A.; Zainol, N. H.; Osman, Z.

    2016-02-01

    The gel polymer electrolytes (GPEs) samples consisting of polyvinylidenefluoride-co-hexafluoropropylene (PVDF-HFP), ethylene carbonate (EC) and propylene carbonate (PC) with different concentrations of magnesium triflate salt, Mg(CF3SO3)2 were prepared using the solution casting technique. The ionic conductivity of the GPEs was studied by using a.c impedance spectroscopy and the sample containing 20 wt% salt exhibited the highest conductivity of 5.11 × l0-3 Scm-1. Ionic transport number of the GPEs shows that the samples contain ionic species as main charge carrier while cationic transport number for the highest conducting sample was found to be 0.27. The electrochemical properties of the GPEs were studied using Linear Sweep Voltammetry (LSV) and Cyclic Voltammetry (CV). The GPEs show high electrochemical stability ˜3.5V (versus Mg2+/Mg) where the highest conducting sample exhibited the highest stability.

  4. STUDY OF THE DIGESTED SLUDGE DEWATERING EFFECTIVENESS USING POLYELECTROLYTE GEL BASED ON ORGANIC POLYMERS

    Directory of Open Access Journals (Sweden)

    Marcin Głodniok

    2016-02-01

    Full Text Available The paper addresses the problems connected with sewage sludge dewatering. The premise of the study was the analysis of whether there are opportunities to increase the efficiency of dewatering sludge, a relatively low-cost involving the use of innovative polymers. The authors analyzed the impact of the new type of polyelectrolyte gel on the effectiveness of dewatering sludge. Laboratory studies were carried out at polyelectrolyte dose selection and laboratory testing on the press chamber designed to simulate the actual operation of sludge dewatering system. Two different doses of polyelectrolyte were tested for dose I – 4 ml/m3 and dose II – 8 ml/m3. The conducted analysis on laboratory press showed an increase of sludge dewatering efficiency by about 2% for dose no. I and by about 13% for dose no. II, in comparison to the test without polyelectrolyte.

  5. Magnetic resonance and conductivity study of a gelatin-based polymer gel electrolyte

    International Nuclear Information System (INIS)

    This work reports results from proton nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR) and complex impedance spectroscopy of gelatin-based polymer gel electrolytes containing chloridric acid, cross-linked with formaldehyde and plasticized with glycerol. Ionic conductivity of 4 × 10−5 S/cm were obtained at room temperature for samples prepared with 0.1 M of HCl. Proton (1H) lineshapes and spin-lattice relaxation times were measured as a function of temperature. Activation energies extracted from the 1H NMR relaxation data are in the range of 23–25 kJ/mol. The EPR spectra, which were carried out in samples doped with copper perchlorate, were interpreted with the aid of an axial spin Hamiltonian and indicate the presence of two different Cu2+ species in axially distorted sites. Copper complexation with both hydrogen and nitrogen was verified by electron spin-echo envelope modulation (ESEEM) techniques.

  6. Rheological and textural properties of microemulsion-based polymer gels with indomethacin.

    Science.gov (United States)

    Froelich, Anna; Osmałek, Tomasz; Kunstman, Paweł; Roszak, Rafał; Białas, Wojciech

    2016-01-01

    In this paper, we present novel microemulsion (ME)-based semisolid polymer gels designed for topical administration of poorly water soluble non-steroidal anti-inflammatory drugs. Indomethacin (IND) was used as a model compound. The ME consisted of castor oil, water, Tween®80 as a surfactant and ethanol as cosurfactant. To obtain the desired consistency of the formulations Carbopol®960 was applied as a thickening agent. The aim of the study was to analyze in detail the mechanical properties of the obtained systems, with special attention paid to the features crucial for topical application. The rheological and textural experiments performed for samples with and without the incorporated drug clearly indicate that flow characteristics, viscoelastic properties and texture profiles were affected by the presence of IND. Novel semisolid formulations with IND described for the first time in this paper can be considered as an alternative for commercially available conventional topical dosage forms. PMID:26204348

  7. Incorporating multislice imaging into x-ray CT polymer gel dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, H., E-mail: holly.johnston@utsw.edu [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 2Y2 (Canada); Hilts, M. [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada and Medical Physics, BC Cancer Agency, Vancouver Island Centre, Victoria, British Columbia V8R 6V5 (Canada); Jirasek, A. [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada and Department of Physics, University of British Columbia—Okanagan Campus, Kelowna, British Columbia V1V 1V7 (Canada)

    2015-04-15

    Purpose: To evaluate multislice computed tomography (CT) scanning for fast and reliable readout of radiation therapy (RT) dose distributions using CT polymer gel dosimetry (PGD) and to establish a baseline assessment of image noise and uniformity in an unirradiated gel dosimeter. Methods: A 16-slice CT scanner was used to acquire images through a 1 L cylinder filled with water. Additional images were collected using a single slice machine. The variability in CT number (N{sub CT}) associated with the anode heel effect was evaluated and used to define a new slice-by-slice background subtraction artifact removal technique for CT PGD. Image quality was assessed for the multislice system by evaluating image noise and uniformity. The agreement in N{sub CT} for slices acquired simultaneously using the multislice detector array was also examined. Further study was performed to assess the effects of increasing x-ray tube load on the constancy of measured N{sub CT} and overall scan time. In all cases, results were compared to the single slice machine. Finally, images were collected throughout the volume of an unirradiated gel dosimeter to quantify image noise and uniformity before radiation is delivered. Results: Slice-by-slice background subtraction effectively removes the variability in N{sub CT} observed across images acquired simultaneously using the multislice scanner and is the recommended background subtraction method when using a multislice CT system. Image noise was higher for the multislice system compared to the single slice scanner, but overall image quality was comparable between the two systems. Further study showed N{sub CT} was consistent across image slices acquired simultaneously using the multislice detector array for each detector configuration of the slice thicknesses examined. In addition, the multislice system was found to eliminate variations in N{sub CT} due to increasing x-ray tube load and reduce scanning time by a factor of 4 when compared to

  8. Electrochemical Impedance Spectroscopy Studies of Magnesium-Based Polymethylmethacrylate Gel Polymer Electroytes

    International Nuclear Information System (INIS)

    Magnesium-based rechargeable batteries might be an interesting future alternative to lithium-based batteries since magnesium compounds are highly abundant in the earth and are environmental friendly. In this work, we have prepared polymethylmethacrylate (PMMA) based gel polymer electrolyte (GPE) films containing two different magnesium salts, which is magnesium triflate, Mg(CF3SO3)2 and magnesium perchlorate, Mg(ClO4)2 using solution casting technique. The ionic conductivity of both gel polymer electrolyte systems was evaluated using a.c impedance spectroscopy. Results show that at room temperature, GPE-Mg(CF3SO3)2 system exhibits the highest conductivity value at 1.27 × 10−3 S cm−1 for the film containing 20 wt.% of Mg(CF3SO3)2 salt, while the highest conductivity value for the GPE-Mg(ClO4)2 system is 3.13 × 10−3 S cm−1 for the film containing 15 wt.% of Mg(ClO4)2 salt. The conductivity-temperature studies of both GPE systems follow the Arrhenius behavior. The activation energies for ionic conduction were determined to be in the range of 0.18–0.26 eV. The transport numbers of magnesium ions in both GPE systems were evaluated using the combination of a.c impedance spectroscopy and d.c polarization techniques. The results obtained indicate that the charge carriers in the GPE films for both systems are predominantly due to ions

  9. Effectiveness of papain gel in venous ulcer treatment: randomized clinical trial1

    OpenAIRE

    Ana Luiza Soares Rodrigues; Beatriz Guitton Renaud Baptista de Oliveira; Débora Omena Futuro; Silvia Regina Secoli

    2015-01-01

    OBJECTIVE: to assess the effectiveness of 2% papain gel compared to 2% carboxymethyl cellulose in the treatment of chronic venous ulcer patients. METHOD: randomized controlled clinical trial with 12-week follow-up. The sample consisted of 18 volunteers and 28 venous ulcers. In the trial group, 2% papain gel was used and, in the control group, 2% carboxymethyl cellulose gel. RESULTS: the trial group showed a significant reduction in the lesion area, especially between the fifth and twelfth wee...

  10. Dye-sensitized solar cell with poly(acrylic acid-co-acrylonitrile)-based gel polymer electrolyte

    International Nuclear Information System (INIS)

    Highlights: ► A nontoxic, easily synthesized poly(acrylic acid-co-acrylonitrile) showed suitable transmittance for dye-sensitized solar cell. ► A cell with relatively large active area fabricated with this polymer material showed acceptable efficiency. ► The gel polymer matrix affected the charge recombination, I3− diffusion, double layer capacitance, and electron lifetime in the cell. - Abstract: A non-conducting, nontoxic poly(acrylic acid-co-acrylonitrile) (PAA) was prepared and used as a supporting matrix for the electrolyte of dye-sensitized solar cells (DSSCs). DSSCs of active area 0.80 cm × 1.10 cm fabricated with PAA, 0.5 M LiI, 0.05 M I2, 0.5 M 3-tert-butylpyridine, and 0.1 M 1-methyl-3-propylimidazolium iodide in 3-methoxypropionitrile solvent showed an average solar energy conversion efficiency of 1.61% under simulated sunlight illumination of 100 mW cm−2, AM 1.5. The effects of the gel polymer matrix on the electrochemical properties of DSSCs were studied using the electrochemical impedance spectroscopy. Relative to the non-gel reference cells, the results showed a decrease in charge recombination, ionic diffusion, and double layer capacitance and an increase in electron lifetime. These results could play an important role in determining the future direction for the development of high-performance gel polymer electrolytes.

  11. Whisker formation of $\\pi$-stacking long polymers: Gel transition in absence of mechanically percolating structures

    CERN Document Server

    Villalobos, Gabriel

    2016-01-01

    We present numerical evidence showing a gel transition occurring in the absence of mechanically percolating structures. The system under consideration consists of long slender laths who interact mostly in the direction perpendicular to their areas; self-assembling into ordered aggregates. An example of such system, which inspired this project, is the poly 3 hexylthiophene (P3HT); a polymer used in the construction of solar cells. In this context, the ordered aggregates are known as whiskers. In order to do the numerical oscillatory shear experiments, we have developed a Brownian dynamics model, in which the potential depends on the orientation of the particles, Brownian Orientational Lath moDel (BOLd). It is characterized by a potential energy that depends both on the angle between orientation vectors, along the long axis of the laths, as well as the vectors normal to the plane of the laths; and which has only one energetic parameter. The storage and loss modulus measured here shown the gel transition, even t...

  12. Phthaloylchitosan-Based Gel Polymer Electrolytes for Efficient Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    S. N. F. Yusuf

    2014-01-01

    Full Text Available Phthaloylchitosan-based gel polymer electrolytes were prepared with tetrapropylammonium iodide, Pr4NI, as the salt and optimized for conductivity. The electrolyte with the composition of 15.7 wt.% phthaloylchitosan, 31.7 wt.% ethylene carbonate (EC, 3.17 wt.% propylene carbonate (PC, 19.0 wt.% of Pr4NI, and 1.9 wt.% iodine exhibits the highest room temperature ionic conductivity of 5.27 × 10−3 S cm−1. The dye-sensitized solar cell (DSSC fabricated with this electrolyte exhibits an efficiency of 3.5% with JSC of 7.38 mA cm−2, VOC of 0.72 V, and fill factor of 0.66. When various amounts of lithium iodide (LiI were added to the optimized gel electrolyte, the overall conductivity is observed to decrease. However, the efficiency of the DSSC increases to a maximum value of 3.71% when salt ratio of Pr4NI : LiI is 2 : 1. This cell has JSC, VOC and fill factor of 7.25 mA cm−2, 0.77 V and 0.67, respectively.

  13. Molecularly imprinted polymer for 2, 4-dichlorophenoxyacetic acid prepared by a sol-gel method

    Indian Academy of Sciences (India)

    Yanli Sun

    2014-07-01

    Based on a sol-gel procedure, a molecularly imprinted polymer (MIP) for 2, 4-dichlorophenoxyacetic acid (2, 4-D) was synthesized, using phenyltrimethoxysilane (PTMOS), aminopropyltriethoxysilane (APTES) as monomers and tetraethoxysilane (TEOS) as cross-linking agent. In addition to the amount of the template, some factors in the sol-gel process: TEOS/APTES/PTMOS molar ratio, H2O/Si molar ratio, CH3CH2OH/Si molar ratio, etc. were investigated in detail. Results show that the optimum conditions for the preparation of the MIPs were 20:1.5:1 (TEOS: APTES: PTMOS), ca. 4 (H2O/Si), ca. 4 (CH3CH2OH/Si), respectively. Effects of various parameters involved in the adsorption process of 2, 4-D on MIP such as incubation time, pH, etc. were also evaluated. It is found that the adsorption attained equilibrium within 3 h, the optimum pH for adsorption was about 7 and the adsorption obeyed Langmuir model. Test results also demonstrated that the present MIP for 2, 4-D had large adsorption capacity (the maximum adsorption concluded from Langmuir model reached 243.3 mg/g) and good selectivity.

  14. Molecular structure effects on the post irradiation diffusion in polymer gel dosimeters

    International Nuclear Information System (INIS)

    Polymer gel dosimeters have specific advantages for recording 3D radiation dose distribution representing a key factor for most of the therapeutic and diagnostic radiation techniques. Radiation-induced polymerization and crosslinking reactions that take place in the dosimeter have been studied for different monomers like acrylamide and N,N-methylene-bis acrylamide (Bis) and most recently for less toxic monomers like N-isopropylacrylamide and Bis. In this work a novel system based on itaconic acid and Bis is proposed, the radical polymerization or gel formation of these monomers has been already studied for the formation of an hydrogel for non dosimetric applications and their reactivity are comparable with the already mentioned systems. Although the 3D structure is maintained after the dosimeter has been irradiated, it is not possible to eliminate the diffusion of the reacted and monomer species in regions of dose gradients within the gel after irradiation. As a consequence the dose information of the dosimeters loose quality over time. The mobility within the gelatin structure of the already mentioned species is related to their chemical structure, and nature. In this work the effect of changes in the chemical structure of the monomers over the dosimetric sensitivity and over the post-irradiation diffusion of species is studied. One of the acrylic acid groups of the itaconic acid molecule is modified to obtain molecules with similar reactivity but different molecular sizes. Dosimetric systems with these modified species, Bis, an antioxidant to avoid oxygen polymerization inhibition, water and gelatin are irradiated in an X-ray tomography at different doses, and the resulting dosimeters are characterized by Raman spectroscopy and optical absorbance to study their feasibility and capabilities as dosimetric systems, and by optical-CT to analyze the diffusion degree after being irradiated. (Author)

  15. Molecular structure effects on the post irradiation diffusion in polymer gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Mattea, F.; Romero, M.; Strumia, M. [Instituto Multidisciplinario de Biologia Vegetal / CONICET, Universidad Nacional de Cordoba, Departamento de Quimica Organica, Ciudad Universitaria, 5000 Cordoba (Argentina); Vedelago, J. [Laboratorio de Investigaciones e Instrumentacion en Fisica Aplicada a la Medicina e Imagenes por Rayos X, Laboratorio 448 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina); Quiroga, A. [Centro de Investigacion y Estudios de Matematica / CONICET, Oficina 318 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina); Valente, M., E-mail: fmattea@gmail.com [Instituto de Fisica E. Gaviola / CONICET, LIIFAMIRx, Oficina 102 FaMAF - UNC, 5000 Cordoba (Argentina)

    2014-08-15

    Polymer gel dosimeters have specific advantages for recording 3D radiation dose distribution representing a key factor for most of the therapeutic and diagnostic radiation techniques. Radiation-induced polymerization and crosslinking reactions that take place in the dosimeter have been studied for different monomers like acrylamide and N,N-methylene-bis acrylamide (Bis) and most recently for less toxic monomers like N-isopropylacrylamide and Bis. In this work a novel system based on itaconic acid and Bis is proposed, the radical polymerization or gel formation of these monomers has been already studied for the formation of an hydrogel for non dosimetric applications and their reactivity are comparable with the already mentioned systems. Although the 3D structure is maintained after the dosimeter has been irradiated, it is not possible to eliminate the diffusion of the reacted and monomer species in regions of dose gradients within the gel after irradiation. As a consequence the dose information of the dosimeters loose quality over time. The mobility within the gelatin structure of the already mentioned species is related to their chemical structure, and nature. In this work the effect of changes in the chemical structure of the monomers over the dosimetric sensitivity and over the post-irradiation diffusion of species is studied. One of the acrylic acid groups of the itaconic acid molecule is modified to obtain molecules with similar reactivity but different molecular sizes. Dosimetric systems with these modified species, Bis, an antioxidant to avoid oxygen polymerization inhibition, water and gelatin are irradiated in an X-ray tomography at different doses, and the resulting dosimeters are characterized by Raman spectroscopy and optical absorbance to study their feasibility and capabilities as dosimetric systems, and by optical-CT to analyze the diffusion degree after being irradiated. (Author)

  16. Influence of the Ionic Liquid Type on the Gel Polymer Electrolytes Properties

    Directory of Open Access Journals (Sweden)

    Juan P. Tafur

    2015-11-01

    Full Text Available Gel Polymer Electrolytes (GPEs composed by ZnTf2 salt, poly(vinylidene fluoride-co-hexafluoropropylene (PVdF-HFP, and different ionic liquids are synthesized using n-methyl-2-pyrrolidone (NMP as solvent. Three different imidazolium-based ionic liquids containing diverse cations and anions have been explored. Structural and electrical properties of the GPEs varying the ZnTf2 concentration are analyzed by ATR-FTIR, DSC, TG, and cyclic voltammetry. Free salt IL-GPEs present distinct behavior because they are influenced by the different IL cations and anions composition. However, inclusion of ZnTf2 salt inside the polymers provide GPEs with very similar characteristics, pointing out that ionic transport properties are principally caused by Zn2+ and triflate movement. Whatever the IL used, the presence of NMP solvent inside the polymer’s matrix turns out to be a key factor for improving the Zn2+ transport inside the GPE due to the interaction between Zn2+ cations and carbonyl groups of the NMP. High values of ionic conductivity, low activation energy values, and good voltammetric reversibility obtained regardless of the ionic liquid used enable these GPEs to be applied in Zn batteries. Capacities of 110–120 mAh·g−1 have been obtained for Zn/IL-GPE/MnO2 batteries discharged at −1 mA·cm−2.

  17. Dye-sensitized solar cell with natural gel polymer electrolytes and f-MWCNT as counter-electrode

    Science.gov (United States)

    Nwanya, A. C.; Amaechi, C. I.; Ekwealor, A. B. C.; Osuji, R. U.; Maaza, M.; Ezema, F. I.

    2015-05-01

    Samples of DSSCs were made with gel polymer electrolytes using agar, gelatin and DNA as the polymer hosts. Anthocyanine dye from Hildegardia barteri flower is used to sensitize the TiO2 electrode, and the spectrum of the dye indicates strong absorptions in the blue region of the solar spectrum. The XRD pattern of the TiO2 shows that the adsorption of the dye did not affect the crystallinity of the electrode. The f-MWCNT indicates graphite structure of the MWCNTs were acid oxidized without significant damage. Efficiencies of 3.38 and 0.1% were obtained using gelatin and DNA gel polymer electrolytes, respectively, for the fabricated dye-sensitized solar cells.

  18. 7Li nuclear magnetic resonance studies of dynamics in a ternary gel polymer electrolyte based on polymeric ionic liquids

    International Nuclear Information System (INIS)

    The influence of the polymeric ionic liquid (PIL) Poly(diallyldimethylammonium bis(trifluoromethylsulfonyl) imide) (PDADMATFSI) on the lithium dynamics was investigated in a ternary gel polymer electrolyte consisting of PDADMATFSI as stabilizing polymer, ionic liquid (1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide, P14TFSI) and lithium salt (lithium bis(trifluoromethylsulfonyl) imide, LiTFSI). The diffusion coefficient of the lithium ions is investigated by pulsed-field-gradient NMR, the conductivity of the electrolyte is determined by impedance spectroscopy. The local lithium dynamics is characterized by 7Li spin lattice relaxation rates (R1). The relaxation rates are well described by Blombergen-Purcell-Pound (BPP) theory at all polymer concentrations (up to 45 mol%), implying that the Li dynamics is governed by one single motional mode. Interestingly, activation energies for this motion decrease from 20 kJ/mol to 15 kJ/mol with increasing polymer content and are independent on the salt content. We thus conclude that the polymer is interacting with the anion coordination shell, which is accompanied by a very beneficial effect on the local lithium dynamics, as the polymer PDADMATFSI reduces the Li-TFSI interactions. This result is promising for further investigations for potential use of PDADMATFSI-containing gels as electrolytes in energy storage devices

  19. Evaluation of the Effects of Inhomogeneities on Dose Profiles Using Polymer Gel Dosimeter and Monte Carlo Simulation in Gamma Knife

    Directory of Open Access Journals (Sweden)

    Tayeb Allahverdi Pourfallah

    2012-03-01

    Full Text Available Introduction Polymer gel dosimeters offer a practical solution to 3D dose verification for conventional radiotherapy as well as intensity-modulated and stereotactic radiotherapy. In this study, EGSnrc calculated and PAGAT polymer gel dosimeter measured dose profiles from single shot irradiation with 18 mm collimator of Gamma Knife in homogeneous and inhomogeneous phantoms were compared with each other. Materials and Methods The head phantom was a custom-built 16 cm diameter plexiglas sphere. Inside the phantom, there were two cubic cutouts for inserting the gel vials and inhomogeneities. Following irradiation with the Gamma Knife unit, the polymer gel dosimeters were scanned with a 1.5 T MRI scanner. For the purpose of simulation the simplified channel of 60Co source of Gamma Knife BEAMnrc and for extracting the 3D dose distribution in the phantom, DOSXYZnrc codes were used. Results Within high isodose levels (>80%, there are dose differences higher than 7%, especially between air inserted and PTFE inserted phantoms, which were obtained using both simulation and experiment. This means that these values exceed the acceptance criterion of conformal radiotherapy and stereotactic radiosurgery (i.e., within some isodose levels, less than 93% of prescription dose are delivered to the target. Conclusion The discrepancies observed between the results obtained from heterogeneous and homogeneous phantoms suggest that Leksell Gamma Knife planning system (LGP predictions which assume the target as a homogeneous material must be corrected in order to take care of the air- and bone-tissue inhomogeneities.

  20. Hierarchical Sol-Gel Transition Induced by Thermosensitive Self-Assembly of an ABC Triblock Polymer in an Ionic Liquid

    Energy Technology Data Exchange (ETDEWEB)

    Kitazawa, Yuzo; Ueki, Takeshi; McIntosh, Lucas D.; Tamura, Saki; Niitsuma, Kazuyuki; Imaizumi, Satoru; Lodge, Timothy P.; Watanabe, Masayoshi (U of Tokyo); (UMM); (Yokohama)

    2016-04-29

    Here we investigate a hierarchical morphology change and accompanying sol–gel transition using a doubly thermosensitive ABC-triblock copolymer in an ionic liquid (IL). The triblock copolymer contains two different lower critical solution temperature (LCST) thermosensitive polymers, poly(benzyl methacrylate) (PBnMA) and poly(2-phenylethyl methacrylate) (PPhEtMA), as the end blocks and poly(methyl methacrylate) (PMMA) as the middle block (PBnMA-b-PMMA-b-PPhEtMA: BMP). BMP undergoes a hierarchical phase transition corresponding to the self-assembly of each of the thermosensitive blocks in the IL, and a sol–gel transition was observed in concentrated, above 10 wt %, polymer solutions. The gelation behavior was affected by polymer concentration, and at 20 wt %, the BMP/IL composite showed a phase transition, with increasing temperature, from solution through a jammed micelle suspension to a physically cross-linked gel. For each phase was formed reversibly and rapidly over the corresponding temperature range. Finally, the jammed micelle and cross-linked gel states were characterized using viscoelastic measurements and small-angle X-ray scattering (SAXS).

  1. Novel configuration of poly(vinylidenedifluoride)-based gel polymer electrolyte for application in lithium-ion batteries

    Science.gov (United States)

    Fasciani, Chiara; Panero, Stefania; Hassoun, Jusef; Scrosati, Bruno

    2015-10-01

    Herein we propose a novel poly(vinylidene difluoride) (PVdF)-based gel polymer electrolyte (GPE) for application in lithium-ion batteries, LIBs. The GPE is prepared under air as a dry, flexible film and directly gelled during LIB assembly with a conventional liquid organic electrolyte. The dry-gel here originally reported maintains its structural integrity due to the presence of crystallized EC-solvent within its matrix that avoids structural collapse, as demonstrated by TGA analysis. By avoiding the use of controlled atmosphere, the GPE is easy to handle and suitable for roll-to-roll scaling-up, i.e. characteristics missed by the common gel membranes. Scanning Electron Microscopy (SEM) evidences a micrometric polymer network of the dry membrane precursor acting as the support matrix for the gelation. Electrochemical impedance spectroscopy (EIS) measurements and galvanostatic tests suggest a good stability of the lithium electrode/gel electrolyte interface and a satisfactory lithium transference number. Cycling tests of gel-electrolyte-based lithium half-cells using lithium iron phosphate (LiFePO4, LFP) and graphite (C), respectively, as counter electrodes, as well as of a full C/LFP lithium-ion battery confirm the suitability of the GPE developed in this work for application in stable, low cost and environmentally friendly energy storage systems.

  2. Gel polymer electrolyte lithium-ion cells with improved low temperature performance

    Energy Technology Data Exchange (ETDEWEB)

    Smart, M.C.; Ratnakumar, B.V.; Behar, A.; Whitcanack, L.D. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Yu, J.-S. [LG Chem/Research Park, P.O. Box 61Yu Song, Science Town, Daejon (Korea); Alamgir, M. [Compact Power, Inc., 1857 Technology Drive, Troy, MI 48083 (United States)

    2007-03-20

    For a number of NASA's future planetary and terrestrial applications, high energy density rechargeable lithium batteries that can operate at very low temperature are desired. In the pursuit of developing Li-ion batteries with improved low temperature performance, we have also focused on assessing the viability of using gel polymer systems, due to their desirable form factor and enhanced safety characteristics. In the present study we have evaluated three classes of promising liquid low-temperature electrolytes that have been impregnated into gel polymer electrolyte carbon-LiMn{sub 2}O{sub 4}-based Li-ion cells (manufactured by LG Chem. Inc.), consisting of: (a) binary EC + EMC mixtures with very low EC-content (10%), (b) quaternary carbonate mixtures with low EC-content (16-20%), and (c) ternary electrolytes with very low EC-content (10%) and high proportions of ester co-solvents (i.e., 80%). These electrolytes have been compared with a baseline formulation (i.e., 1.0 M LiPF{sub 6} in EC + DEC + DMC (1:1:1%, v/v/v), where EC, ethylene carbonate, DEC, diethyl carbonate, and DMC, dimethyl carbonate). We have performed a number of characterization tests on these cells, including: determining the rate capacity as a function of temperature (with preceding charge at room temperature and also at low temperature), the cycle life performance (both 100% DOD and 30% DOD low earth orbit cycling), the pulse capability, and the impedance characteristics at different temperatures. We have obtained excellent performance at low temperatures with ester-based electrolytes, including the demonstration of >80% of the room temperature capacity at -60 C using a C/20 discharge rate with cells containing 1.0 M LiPF{sub 6} in EC + EMC + MB (1:1:8%, v/v/v) (MB, methyl butyrate) and 1.0 M LiPF{sub 6} in EC + EMC + EB (1:1:8%, v/v/v) (EB, ethyl butyrate) electrolytes. In addition, cells containing the ester-based electrolytes were observed to support 5C pulses at -40 C, while still

  3. Three-Dimensional Nanoporous Cellulose Gels as a Flexible Reinforcement Matrix for Polymer Nanocomposites.

    Science.gov (United States)

    Shi, Zhuqun; Huang, Junchao; Liu, Chuanjun; Ding, Beibei; Kuga, Shigenori; Cai, Jie; Zhang, Lina

    2015-10-21

    With the world's focus on utilization of sustainable natural resources, the conversion of wood and plant fibers into cellulose nanowhiskers/nanofibers is essential for application of cellulose in polymer nanocomposites. Here, we present a novel fabrication method of polymer nanocomposites by in-situ polymerization of monomers in three-dimensionally nanoporous cellulose gels (NCG) prepared from aqueous alkali hydroxide/urea solution. The NCG have interconnected nanofibrillar cellulose network structure, resulting in high mechanical strength and size stability. Polymerization of the monomer gave P(MMA/BMA)/NCG, P(MMA/BA)/NCG nanocomposites with a volume fraction of NCG ranging from 15% to 78%. SEM, TEM, and XRD analyses show that the NCG are finely distributed and preserved well in the nanocomposites after polymerization. DMA analysis demonstrates a significant improvement in tensile storage modulus E' above the glass transition temperature; for instance, at 95 °C, E' is increased by over 4 orders of magnitude from 0.03 MPa of the P(MMA/BMA) up to 350 MPa of nanocomposites containing 15% v/v NCG. This reinforcement effect can be explained by the percolation model. The nanocomposites also show remarkable improvement in solvent resistance (swelling ratio of 1.3-2.2 in chloroform, acetone, and toluene), thermal stability (do not melt or decompose up to 300 °C), and low coefficients of thermal expansion (in-plane CTE of 15 ppm·K(-1)). These nanocomposites will have great promising applications in flexible display, packing, biomedical implants, and many others. PMID:26397710

  4. Effects of refractive index mismatch in optical CT imaging of polymer gel dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Manjappa, Rakesh; Makki S, Sharath; Kanhirodan, Rajan, E-mail: rajan@physics.iisc.ernet.in [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Kumar, Rajesh [Radiological Physics and Advisory Division, BARC, Mumbai 400094 (India)

    2015-02-15

    Purpose: Proposing an image reconstruction technique, algebraic reconstruction technique-refraction correction (ART-rc). The proposed method takes care of refractive index mismatches present in gel dosimeter scanner at the boundary, and also corrects for the interior ray refraction. Polymer gel dosimeters with high dose regions have higher refractive index and optical density compared to the background medium, these changes in refractive index at high dose results in interior ray bending. Methods: The inclusion of the effects of refraction is an important step in reconstruction of optical density in gel dosimeters. The proposed ray tracing algorithm models the interior multiple refraction at the inhomogeneities. Jacob’s ray tracing algorithm has been modified to calculate the pathlengths of the ray that traverses through the higher dose regions. The algorithm computes the length of the ray in each pixel along its path and is used as the weight matrix. Algebraic reconstruction technique and pixel based reconstruction algorithms are used for solving the reconstruction problem. The proposed method is tested with numerical phantoms for various noise levels. The experimental dosimetric results are also presented. Results: The results show that the proposed scheme ART-rc is able to reconstruct optical density inside the dosimeter better than the results obtained using filtered backprojection and conventional algebraic reconstruction approaches. The quantitative improvement using ART-rc is evaluated using gamma-index. The refraction errors due to regions of different refractive indices are discussed. The effects of modeling of interior refraction in the dose region are presented. Conclusions: The errors propagated due to multiple refraction effects have been modeled and the improvements in reconstruction using proposed model is presented. The refractive index of the dosimeter has a mismatch with the surrounding medium (for dry air or water scanning). The algorithm

  5. Final Technical Report for 'Investigations of the Role of Protozoa in Transformations of Marine Biopolymers using Phaeocytis Polymer Gels as a Model'

    Energy Technology Data Exchange (ETDEWEB)

    Lessard, Evelyn

    2003-04-01

    OAK B188 Biopolymers and biopolymer gels are major components of the organic carbon and nitrogen pools in the ocean. The overall goal of this project was to better understand the chemical and physical transformations of polymers and polymer gels in coastal waters that are mediated by protists and bacteria. Bacteria are thought to be the major consumers of marine biopolymers, but direct consumption by protists, and the interactions of bacteria and protists, may also be important but largely unexplored pathways of biopolymer cycling. Phaeocystis is a colonial prymnesiophyte alga that produces large amounts of polymer gels that have similar properties to those found in the dissolved organic carbon (DOC) pool namely, they are tangled networks of polymers held together by calcium bridges. We used the polymers and polymer gels produced by two species of Phaeocystis (from the North Atlantic and Antarctica) as models to examine the consumption, degradation and alteration of algal polymer gels by protists and bacteria. We developed several novel methods and approaches to examine polymer gel transformations. One tool was an immunoassay (ELISA) using a polyclonal antibody specific to Phaeocystis polymers that allowed us to track the polymer gels in situ and in laboratory experiments. We successfully tested the ability of the immunoassay to detect and quantify Phaeocystis polymer carbon in water from the Ross Sea, Gulf of Alaska and North Water (Greenland). This exciting new approach demonstrates the usefulness of antibodies for detecting and quantifying a specific component of the DOM pool in natural samples and provides a method for following the sources and sinks of that component. We also developed a fluorescent immunoassay procedure with the antibody to visualize and quantify ingested polymers in single protist cells. In experiments with polymer gels as the sole organic source (no prey), prey plus polymer gels, and prey without polymer gels, we determined that some

  6. Developing stable, low impedance interface between metallic lithium anode and polyacrylonitrile-based polymer gel electrolyte by preliminary voltage cycling

    Energy Technology Data Exchange (ETDEWEB)

    Sotomura, Tadashi; Adachi, Kinichi [Matsushita Electric Industrial Co. Ltd., Moriguchi, Osaka (Japan). Central Research Lab.; Taguchi, Makoto; Iwaku, Masahiro; Tatsuma, Tetsu; Oyama, Noboru [Tokyo Univ. of Agriculture and Technolgy (Japan). Dept. of Applied Chemistry

    1999-09-01

    The metallic lithium anode surface facing to a gel-like polyacrylonitrile polymer electrolyte (gel-SPE) was tried to be stabilized by preliminary voltage cycling. Through voltage cycling from +0.5 to -0.5 V at a scan rate of 10 mV/s at 20 C immediately after assembling a cell having a configuration of Li/gel-SPE/Li, the cell impedance at 100 Hz was kept below 100 {omega} for the cells with a gel-SPE containing LiBF{sub 4} over 230 days at 20 C. The cells with a gel-SPE containing LiPF{sub 6} required preliminary voltage cycling at a voltage higher than 0.5 V and at an elevated temperature of 60 C to obtain and keep a lower impedance during storage. The impedance at 10 kHz which represented the bulk resistance of gel-SPE was almost the same for both cells and constant during storage, around 15 {omega}. This was confirmed in the cell of Li/gel-SPE/DMcT + polyaniline composite cathode (DMcT=2,5-dimercapto-1,3,4-thiadiazole). The metallic lithium anode surface before and after the voltage cycling was subjected to X-ray photoelectron spectroscopy (XPS) analysis: Li{sub 2}CO{sub 3} disappeared and LiF-LiOH remained in the surface layer after the voltage cycling for the LiBF{sub 4} gel-SPE cell while for the LiPF{sub 6} gel-SPE cell, a dense and thin LiF surface layer was broken into a thicker LiF-LiOH layer. The layer consisting of mainly LiF and LiOH which was formed by preliminary voltage cycling was considered to stabilize the interface. (orig.)

  7. A 3,3′-dichlorobenzidine-imprinted polymer gel surface plasmon resonance sensor based on template-responsive shrinkage

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Chunyan; Gao, Jigang, E-mail: gjg@sdau.edu.cn; Zhang, Lili; Zhou, Jie, E-mail: zhoujie@sdau.edu.cn

    2014-02-17

    Graphical abstract: -- Highlights: •Based on template-responsive shrinkage of imprinted gel film, a novel surface plasmon resonance (SPR) sensor is prepared. •The relevant electrochemical parameters are optimized. •The imprinted gel-SPR system has great capability for providing highly sensitive and selective analysis of 3,3′-dichlorobenzidine. •The present SPR sensor was successfully employed to detect 3,3′-dichlorobenzidine in tap water and soil samples. -- Abstract: Molecularly imprinted polymer gel film on the gold substrate of a chip was prepared with minute amount of cross-linker for the fabrication of a surface plasmon resonance (SPR) sensor sensitive to 3,3′-dichlorobenzidine. The molecularly imprinted gel film was anchored on a gold chip by a surface-bound photo-radical initiator. The sensing of 3,3′-dichlorobenzidine is based on responsive shrinkage of the imprinted polymer gel film that is triggered by target binding. This change can improve the responsiveness of the imprinted SPR sensor to 3,3′-dichlorobenzidine. The molecularly imprinted polymer gel film was characterized with contact angle measurements, electrochemical impedance spectroscopy, cyclic voltammogram, swelling measurements and atomic force microscopy. The changes of SPR spectroscopy wavenumber shifts revealed that the imprinted gel sensing film can ‘memorize’ the binding of 3,3′-dichlorobenzidine compared to non-imprinted one. The imprinted gel-SPR sensor showed a linear response in the range of 9.0 × 10{sup −12} to 5.0 × 10{sup −10} mol L{sup −1} (R{sup 2} = 0.9998) for the detection of 3,3′-dichlorobenzidine, and it also exhibited high selectivity to 3,3′-dichlorobenzidine compared to its structurally related analogues. We calculated the detection limits to be 0.471 ng L{sup −1} for tap water and 0.772 ng kg{sup −1} for soil based on a signal to noise ratio of 3. The method showed good recoveries and precision for the samples spiked with 3,3

  8. Supramolecular liquid-crystal gels formed by polyfluorene-based π-conjugated polymer for switchable anisotropic scattering device.

    Science.gov (United States)

    Chen, Jun-Wei; Huang, Chiu-Chang; Chao, Chih-Yu

    2014-05-14

    To overcome the problem of high driving voltage and low contrast ratio in the switchable scattering device of conventional liquid-crystal (LC) physical gel, a new type of supramolecular LC physical gel has been developed and fabricated through the fibrous self-assembly of the polyfluorene-based π-conjugated polymer, poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT), in nematic LC mixture E7. It was found that the rubbed interface between the LC molecules and polyimide layer can induce the LC physical gels to demonstrate fantastic light scattering characteristic. The gels with oriented self-assembled supramolecular structures exhibiting significant anisotropic light scattering in the main-chain direction of the F8BT molecules under an extremely low driving voltage (ca. 2.7 V) are reported for the first time. In addition, the contrast ratio can be reached exceeding 1000. In contrast to conventional LC physical gels, the large reduction of driving voltages of the supramolecular gel provides great possibility for application in various electro-optical devices such as tunable polarizers, transflective displays, and polarized light modulators. PMID:24724859

  9. Three-dimensional dosimetry of TomoTherapy by MRI-based polymer gel technique.

    Science.gov (United States)

    Watanabe, Yoichi; Gopishankar, N

    2010-09-14

    Verification of the dose calculation model and the software used for treatment planning is an important step for accurate radiation delivery in radiation therapy. Using BANG3 polymer gel dosimeter with a 3 Tesla magnetic resonance imaging (MRI) scanner, we examined the accuracy of TomoTherapy treatment planning and radiation delivery. We evaluated one prostate treatment case and found the calculated three-dimensional (3D) dose distributions agree with the measured 3D dose distributions with an exception in the regions where the dose was much smaller (25% or less) than the maximum dose (2.5 Gy). The analysis using the gamma-index (3% dose difference and 3 mm distance-to-agreement) for a volume of 12 cm × 11 cm × 9 cm containing the planning target volume showed that the gamma values were smaller than unity for 53% of the voxels. Our measurement protocol and analysis tools can be easily applied to the evaluation of other newer complex radiation delivery techniques, such as intensity-modulated arc therapy, with a reasonably low financial investment.

  10. Gel polymer electrolytes based on nanofibrous polyacrylonitrile–acrylate for lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dul-Sun [Department of Chemical and Biological Engineering, Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Woo, Jang Chang [Department of Textile Engineering, Inha University, 100 Inharo, Nam-gu Incheon 402-751 (Korea, Republic of); Youk, Ji Ho, E-mail: youk@inha.ac.kr [Department of Textile Engineering, Inha University, 100 Inharo, Nam-gu Incheon 402-751 (Korea, Republic of); Manuel, James [Department of Chemical and Biological Engineering, Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Ahn, Jou-Hyeon, E-mail: jhahn@gnu.ac.kr [Department of Chemical and Biological Engineering, Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Department of Materials Engineering and Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of)

    2014-10-15

    Graphical abstract: - Highlights: • Nanofibrous polyacrylonitrile–acrylate membranes were prepared by electrospinning. • Trimethylolpropane triacrylate was used as a crosslinking agent of fibers. • The GPE based on PAN–acrylate (1/0.5) showed good electrochemical properties. - Abstract: Nanofibrous membranes for gel polymer electrolytes (GPEs) were prepared by electrospinning a mixture of polyacrylonitrile (PAN) and trimethylolpropane triacrylate (TMPTA) at weight ratios of 1/0.5 and 1/1. TMPTA is used to achieve crosslinking of fibers thereby improving mechanical strength. The average fiber diameters increased with increasing TMPTA concentration and the mechanical strength was also improved due to the enhanced crosslinking of fibers. GPEs based on electrospun membranes were prepared by soaking them in a liquid electrolyte of 1 M LiPF{sub 6} in ethylene carbonate (EC)/dimethyl carbonate (DMC) (1:1, v/v). The electrolyte uptake and ionic conductivity of GPEs based on PAN and PAN–acrylate (weight ratio; 1/1 and 1/0.5) were investigated. Ionic conductivity of GPEs based on PAN–acrylate was the highest for PAN/acrylate (1/0.5) due to the proper swelling of fibers and good affinity with liquid electrolyte. Both GPEs based on PAN and PAN–acrylate membranes show good oxidation stability, >5.0 V vs. Li/Li{sup +}. Cells with GPEs based on PAN–acrylate (1/0.5) showed remarkable cycle performance with high initial discharge capacity and low capacity fading.

  11. ZnTe Semiconductor-Polymer Gel Composited Electrolyte for Conversion of Solar Energy

    Directory of Open Access Journals (Sweden)

    Wonchai Promnopas

    2014-01-01

    Full Text Available Nanostructured cubic p-type ZnTe for dye sensitized solar cells (DSSCs was synthesized from 1 : 1 molar ratio of Zn : Te by 600 W and 900 W microwave plasma for 30 min. In this research, their green emissions were detected at the same wavelengths of 563 nm, the energy gap (Eg at 2.24 eV, and three Raman shifts at 205, 410, and 620 cm−1. The nanocomposited electrolyte of quasisolid state ZnO-DSSCs was in correlation with the increase in the JSC, VOC, fill factor (ff, and efficiency (η by increasing the wt% of ZnTe-GPE (gel polymer electrolyte to an optimum value and decreased afterwards. The optimal ZnO-DSSC performance was achieved for 0.20 wt% ZnTe-GPE with the highest photoelectronic energy conversion efficiency at 174.7% with respect to that of the GPE without doping of p-type ZnTe.

  12. Determination of the interaction using FTIR within the composite gel polymer electrolyte

    Science.gov (United States)

    Huang, Yun; Ma, Xiaoyan; Wang, Xu; Liang, Xiao

    2013-01-01

    In the previous research, the gel polymer electrolyte (GPE) which consisted of poly(methyl methacrylate) (PMMA) matrix, propylene carbonate (PC), LiClO4 and OREC (Rectorite modified with dodecyl benzyl dimethyl ammonium chloride), achieved satisfactory properties. In the paper, the interaction between components was quantitatively determined. Characterization of interaction of Cdbnd O in PC and PMMA with Li+ and OH group on OREC surface has been thoroughly examined using FTIR, respectively. The quantitative analysis of FTIR shows that the absorptivity coefficient a of PMMA/LiClO4, PC/LiClO4, PC/OREC and PMMA/OREC is 0.902, 0.113, 0.430 and 0.753, respectively, which means that the Li+ or OH bonded Cdbnd O is more sensitive than the free Cdbnd O in FTIR spectra. The limit value of bonded Cdbnd O equivalent fraction of PMMA/LiClO4, PC/LiClO4, PC/OREC and PMMA/OREC is 17%, 94%, 57% and 20%, respectively, which implies that all the interaction within the components is reversible and the intensity of interaction is ordered as PC/LiClO4, PC/OREC, PMMA/OREC and PMMA/LiClO4.

  13. Femtosecond laser pulse filamentation characterized by polymer gel dosimetry and Fricke dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Meesat, Ridthee; Allard, Jean-Francois; Houde, Daniel; Tremblay, Luc; Khalil, Abdelouahed; Jay-Gerin, Jean-Paul; Lepage, Martin, E-mail: Martin.Lepage@USherbrooke.c [Departement de medecine nucleaire et de radiobiologie, Faculte de medecine et des sciences de la sante, Universite de Sherbrooke, Sherbrooke (Quebec) J1H 5N4 (Canada)

    2010-11-01

    A femtosecond laser pulse that can generate water radiolysis species was studied in view of its potential medical and biological applications. Intense ultra-short laser pulses can propagate in liquid water, leading to self-focusing and filamentation. Briefly, electrons produced by either multiphoton or tunnel ionization are further accelerated by the electric field of the pulse in an inverse Bremsstrahlung effect. If the electrons acquire enough kinetic energy, they will give rise to a second generation of electrons by impact ionization of other molecules in an avalanche-like process. The geometry and trajectory of femtosecond filaments were captured within a polymer gel dosimeter and imaged by magnetic resonance imaging (MRI) at high resolution. The results revealed that changing pulse duration modifies the penetration of the filament track in the medium. In addition, we used Fricke dosimetry to measure the absorbed dose and dose rate of the femtosecond laser pulse filamentation. A very high dose rate of 5.3 x 10{sup 12} Gy/s was calculated in filaments having a diameter of {approx}600 {mu}m.

  14. Hydroxypropyl Cellulose Based Non-Volatile Gel Polymer Electrolytes for Dye-Sensitized Solar Cell Applications using 1-methyl-3-propylimidazolium iodide ionic liquid

    Science.gov (United States)

    Khanmirzaei, Mohammad Hassan; Ramesh, S.; Ramesh, K.

    2015-12-01

    Gel polymer electrolytes using imidazolium based ionic liquids have attracted much attention in dye-sensitized solar cell applications. Hydroxypropyl cellulose (HPC), sodium iodide (NaI), 1-methyl-3-propylimidazolium iodide (MPII) as ionic liquid (IL), ethylene carbonate (EC) and propylene carbonate (PC) are used for preparation of non-volatile gel polymer electrolyte (GPE) system (HPC:EC:PC:NaI:MPII) for dye-sensitized solar cell (DSSC) applications. The highest ionic conductivity of 7.37 × 10-3 S cm-1 is achieved after introducing 100% of MPII with respect to the weight of HPC. Temperature-dependent ionic conductivity of gel polymer electrolytes is studied in this work. XRD patterns of gel polymer electrolytes are studied to confirm complexation between HPC polymer, NaI and MPII. Thermal behavior of the GPEs is studied using simultaneous thermal analyzer (STA) and differential scanning calorimetry (DSC). DSSCs are fabricated using gel polymer electrolytes and J-V centeracteristics of fabricated dye sensitized solar cells were analyzed. The gel polymer electrolyte with 100 wt.% of MPII ionic liquid shows the best performance and energy conversion efficiency of 5.79%, with short-circuit current density, open-circuit voltage and fill factor of 13.73 mA cm-2, 610 mV and 69.1%, respectively.

  15. Protocol and cell responses in three-dimensional conductive collagen gel scaffolds with conductive polymer nanofibres for tissue regeneration

    OpenAIRE

    Sirivisoot, Sirinrath; Pareta, Rajesh; Harrison, Benjamin S.

    2014-01-01

    It has been established that nerves and skeletal muscles respond and communicate via electrical signals. In regenerative medicine, there is current emphasis on using conductive nanomaterials to enhance electrical conduction through tissue-engineered scaffolds to increase cell differentiation and tissue regeneration. We investigated the role of chemically synthesized polyaniline (PANI) and poly(3,4-ethylenedioxythiophene) (PEDOT) conductive polymer nanofibres for conductive gels. To mimic a na...

  16. Tracer diffusion in a polymer gel: simulations of static and dynamic 3D networks using spherical boundary conditions

    Science.gov (United States)

    Kamerlin, Natasha; Elvingson, Christer

    2016-11-01

    We have investigated an alternative to the standard periodic boundary conditions for simulating the diffusion of tracer particles in a polymer gel by performing Brownian dynamics simulations using spherical boundary conditions. The gel network is constructed by randomly distributing tetravalent cross-linking nodes and connecting nearest pairs. The final gel structure is characterised by the radial distribution functions, chain lengths and end-to-end distances, and the pore size distribution. We have looked at the diffusion of tracer particles with a wide range of sizes, diffusing in both static and dynamic networks of two different volume fractions. It is quantitatively shown that the dynamical effect of the network becomes more important in facilitating the diffusional transport for larger particle sizes, and that one obtains a finite diffusion also for particle sizes well above the maximum in the pore size distribution.

  17. Tracer diffusion in a polymer gel: simulations of static and dynamic 3D networks using spherical boundary conditions.

    Science.gov (United States)

    Kamerlin, Natasha; Elvingson, Christer

    2016-11-30

    We have investigated an alternative to the standard periodic boundary conditions for simulating the diffusion of tracer particles in a polymer gel by performing Brownian dynamics simulations using spherical boundary conditions. The gel network is constructed by randomly distributing tetravalent cross-linking nodes and connecting nearest pairs. The final gel structure is characterised by the radial distribution functions, chain lengths and end-to-end distances, and the pore size distribution. We have looked at the diffusion of tracer particles with a wide range of sizes, diffusing in both static and dynamic networks of two different volume fractions. It is quantitatively shown that the dynamical effect of the network becomes more important in facilitating the diffusional transport for larger particle sizes, and that one obtains a finite diffusion also for particle sizes well above the maximum in the pore size distribution. PMID:27662260

  18. Investigation of the Spatial Resolution of MR-Based Polymer Gel Dosimetry versus Film Densitometry using Dose Modulation Transfer Function

    Directory of Open Access Journals (Sweden)

    Reza Moghadam-Drodkhani

    2011-03-01

    Full Text Available Introduction: The conventional methods of dosimetry are not capable of dosimetry in such a small volume of less than one cubic millimeter. Although the polymer gel dosimetry method based on magnetic resonance imaging (MRI could achieve three dimensional dosimetry with high resolution, a spatial resolution evaluation based on gel dose modulation transfer function has not been investigated yet. Therefore, in this study, the spatial resolution of two systems of film densitometry and polymer gel dosimetry based on MRI has been evaluated by using the dose modulation transfer function (DMTF.   Material and Methods: Kodak therapy verification films and MAGICA polymer gel samples were positioned below a brass absorption grid with different periodic slices (a/2= 280, 525, 1125 μm, which was placed in a water bath container to avoid regions of dose build-up just below the absorption grid and then irradiated with Cobalt-60 photons on a Theratron external-beam treatment unit. Dose variation under the brass grid was determined using a calibration curve, while transverse relaxation time (T2 as the selective parameter in a dose image based on multiple echo MRI with 1.5 Tesla GE Signa Echo Speed system (FOV=10 cm, matrix size=512 ×512, pixel size =0.199×0.199 mm2, TE = 20, 40, 60, 80 ms, TR=4200 ms, NEX = 4, slice thickness=2 mm, gap=1 mm was calculated. DMTF from the modulation depths of T2 and variation in film optical density after calibration would be achieved. The results of polymer gel were compared with film. Results: After deriving the dose distribution profile under the absorption grid, minima and maxima at the smallest period of a = 560 μm could scarcely be resolved, but the modulations due to a=2250 μm and a = 1050 μm grids could be discerned. The modulation depth for a=2250 μm grid was set to 100% and the other modulations were subsequently referred to this maximum modulation. For film densitometry at a = 1050 μm, the modulation depth was

  19. Scaling of the kinetics of slow aggregation and gel formation for a fluorinated polymer colloid.

    Science.gov (United States)

    Sandkühler, Peter; Sefcik, Jan; Morbidelli, Massimo

    2005-03-01

    The aggregation and gelation kinetics in moderately concentrated (0.004 polymer particles has been studied. The aggregation was adjusted to proceed slowly enough to allow a convenient characterization of the kinetics through static and dynamic light scattering on quenched and diluted samples. A population balance model based on second-order aggregation rates is developed to compute the time evolution of the cluster mass distribution, from which we calculate the values of the average radii and structure factor measured by light scattering, so as to allow a direct comparison between measured and calculated quantities. The model suggests the introduction of a dimensionless time which allows the scaling of all the aggregation data on unique master curves defined by only two parameters: the exponent of the power-law aggregation kernel, lambda, and the aggregate fractal dimension, d(f). The predicted master curves were observed experimentally, which confirms the validity of the aggregation model and allows the unique determination of the kinetic and structural parameters of the aggregation process. The cluster growth behavior, although significantly slower than DLCA, shows power-law kinetics rather than the exponential one typical of RLCA and the cluster structure is characterized by an unexpectedly small fractal dimension, d(f) = 1.7. The occurrence of gelation has been characterized using small amplitude oscillatory shearing to monitor the time evolution of the elastic modulus. It is found that also these curves, together with the gel time value, scale with the stability ratio of primary particles for a given solid volume fraction. We further use the model to calculate the cumulative occupied volume fraction of the growing aggregates and quantify in this way the increasing space filling, which is solid volume fraction dependent. The experimentally determined dimensionless gel times, which are also solid volume

  20. Polymer gels impregnated with gold nanoparticles implemented for measurements of radiation dose enhancement in synchrotron and conventional radiotherapy type beams

    International Nuclear Information System (INIS)

    Normoxic type polyacrylamide gel (nPAG) dosimeters are established for dose quantification in three-dimensions for radiotherapy and hence represent an adequate dosimeter for quantification of the dose variation due to the existence of the gold nanoparticles (AuNPs) in the target during irradiation. This work compared the degree of polymerisation in gel doped with nanoparticles (nPAG–AuNP) with control gel samples when irradiated by various sources. Samples were irradiated with a synchrotron radiation source of mean energy 125 keV, 80 kV X-ray beams from superficial therapy machine (SXRT), 6 MV X-rays and 6 MeV electron beams from linear accelerator. Analysis of the dose–response relation was used to determine a dose enhancement factor (DEF) of 1.76 ± 0.34 and 1.64 ± 0.44 obtained for samples irradiated with kilovoltage X-rays energy from synchrotron source and SXRT respectively. Similarly, including AuNPs in gel results in a DEF of approximately 1.37 ± 0.35 when irradiated by an electron beam and 1.14 ± 0.28 for high energy X-ray beams. The results demonstrate the use of AuNPs embedded in polymer gels for measuring the enhancement of radiation caused by metallic nanoparticles.

  1. EFFICIENT FORMULATION AND CHARACTERIZATION OF FLURBIPROFEN TRANSDERMAL GEL USING WATER SOLUBLE POLYACRYLAMIDE POLYMER

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    Jeevaprakash Ganapathi*1 and Dheivanai Jeevaprakash 2

    2012-06-01

    Full Text Available High molecular weights water soluble homopolymer type of acrylamide was reported to obtain very high viscosity in low concentration, transparency, film forming properties and useful in formation of transdermal gel. The flurbiprofen gels were prepared by using different concentration of polyacrylamide for topical drug delivery with an aim to gradually increase transparency and spreadability. These preparations were further compared with marketed known flurbiprofen gel. Spreadability and consistency of polyacrylamide gel containing flurbiprofen gel (S9 were 6.5g.cm/sec and 5mm as compared to 5.5g.cm/sec and 10mm respectively of known marketed gel, indicating good spreadability nature and consistency of the prepared gel (S9. The transparency nature of prepared batch (S9 was good as compared to the known marketed gel. The percent drug release was 97.85 and 98.84 from S9 and known marketed gel respectively. No irritation was felt in the skin irritation test. Stability studies conducted under accelerated condition was shown satisfactory results. It can be concluded that polyacrylamide gel containing flurbiprofen gel showed good consistency, spreadability, homogeneity and stability and had wider prospect for topical preparations.

  2. Assessment and characterization of the total geometric uncertainty in Gamma Knife radiosurgery using polymer gels

    International Nuclear Information System (INIS)

    Purpose: This work proposes and implements an experimental methodology, based on polymer gels, for assessing the total geometric uncertainty and characterizing its contributors in Gamma Knife (GK) radiosurgery. Methods: A treatment plan consisting of 26, 4-mm GK single shot dose distributions, covering an extended region of the Leksell stereotactic space, was prepared and delivered to a polymer gel filled polymethyl methacrylate (PMMA) head phantom (16 cm diameter) used to accurately reproduce every link in the GK treatment chain. The center of each shot served as a “control point” in the assessment of the GK total geometric uncertainty, which depends on (a) the spatial dose delivery uncertainty of the PERFEXION GK unit used in this work, (b) the spatial distortions inherent in MR images commonly used for target delineation, and (c) the geometric uncertainty contributor associated with the image registration procedure performed by the Leksell GammaPlan (LGP) treatment planning system (TPS), in the case that registration is directly based on the apparent fiducial locations depicted in each MR image by the N-shaped rods on the Leksell localization box. The irradiated phantom was MR imaged at 1.5 T employing a T2-weighted pulse sequence. Four image series were acquired by alternating the frequency encoding axis and reversing the read gradient polarity, thus allowing the characterization of the MR-related spatial distortions. Results: MR spatial distortions stemming from main field (B0) inhomogeneity as well as from susceptibility and chemical shift phenomena (also known as sequence dependent distortions) were found to be of the order of 0.5 mm, while those owing to gradient nonlinearities (also known as sequence independent distortions) were found to increase with distance from the MR scanner isocenter extending up to 0.47 mm at an Euclidean distance of 69.6 mm. Regarding the LGP image registration procedure, the corresponding average contribution to the total

  3. Three dimensional visualization and measurement of conformal dose distributions using magnetic resonance imaging of BANG polymer gel dosimeters

    International Nuclear Information System (INIS)

    Purpose/objective: The measurement of complex dose distributions (those created by irradiation through multiple beams or multiple source dwell positions) requires a dosimeter that can integrate the dose during a complete treatment. Integrating dosimeter devices generally are capable of measuring only dose at a point (ion chamber, diode, TLD) or in a plane (film). With increasing use of conformal dose distributions, requiring shaped, noncoplanar beams, there will be an increased requirement for a dosimeter that can record and display a 3-D dose distribution. The use of a 3-D dosimeter will be required to confirm the accuracy of treatment plans produced by the current generation of 3-D treatment planning computers. Materials and methods: We have previously described the use of a Fricke-infused gel and magnetic resonance imaging (MRI) to demonstrate the localization of stereotactic beams. The recently developed BANG polymer gel dosimetry system (MGS Research, Inc., Guilford, CT), based on radiation-induced chain polymerization of acrylic monomers dispersed in a tissue-equivalent gel, surpasses the Fricke-gel method by providing accurate, quantitative dose distribution data that do not deteriorate with time. The improved BANG2 formulation contains 3% N, N'-methylene-bisacrylamide, 3% acrylic acid, 1% sodium hydroxide, 5% gelatin, and 88% water, where all percentages are by weight. The gel was poured into volumetric flasks, of dimensions comparable to a human head. The gels were irradiated with complex beam arrangements, similar to those used for conformal radiation therapy. Images of the gels were acquired using a Siemens 1.5T imager and a Hahn spin-echo pulse sequence (90 deg. -τ-180 deg. -τ-acquire, for different values of τ). The images were transferred via network to a Macintosh computer for which a data analysis and display program was written. The program calculates R2 maps on the basis of multiple TE images, using a monoexponential non-linear least squares

  4. SU-E-T-102: Determination of Dose Distributions and Water-Equivalence of MAGIC-F Polymer Gel for 60Co and 192Ir Brachytherapy Sources

    Energy Technology Data Exchange (ETDEWEB)

    Quevedo, A; Nicolucci, P [University of Sao Paulo, Ribeirao Preto, SP (Brazil)

    2014-06-01

    Purpose: Analyse the water-equivalence of MAGIC-f polymer gel for {sup 60}Co and {sup 192}Ir clinical brachytherapy sources, through dose distributions simulated with PENELOPE Monte Carlo code. Methods: The real geometry of {sup 60} (BEBIG, modelo Co0.A86) and {sup 192}192Ir (Varian, model GammaMed Plus) clinical brachytherapy sources were modelled on PENELOPE Monte Carlo simulation code. The most probable emission lines of photons were used for both sources: 17 emission lines for {sup 192}Ir and 12 lines for {sup 60}. The dose distributions were obtained in a cubic water or gel homogeneous phantom (30 × 30 × 30 cm{sup 3}), with the source positioned in the middle of the phantom. In all cases the number of simulation showers remained constant at 10{sup 9} particles. A specific material for gel was constructed in PENELOPE using weight fraction components of MAGIC-f: wH = 0,1062, wC = 0,0751, wN = 0,0139, wO = 0,8021, wS = 2,58×10{sup −6} e wCu = 5,08 × 10{sup −6}. The voxel size in the dose distributions was 0.6 mm. Dose distribution maps on the longitudinal and radial direction through the centre of the source were used to analyse the water-equivalence of MAGIC-f. Results: For the {sup 60} source, the maximum diferences in relative doses obtained in the gel and water were 0,65% and 1,90%, for radial and longitudinal direction, respectively. For {sup 192}Ir, the maximum difereces in relative doses were 0,30% and 1,05%, for radial and longitudinal direction, respectively. The materials equivalence can also be verified through the effective atomic number and density of each material: Zef-MAGIC-f = 7,07 e .MAGIC-f = 1,060 g/cm{sup 3} and Zef-water = 7,22. Conclusion: The results showed that MAGIC-f is water equivalent, consequently being suitable to simulate soft tissue, for Cobalt and Iridium energies. Hence, gel can be used as a dosimeter in clinical applications. Further investigation to its use in a clinical protocol is needed.

  5. Electric double-layer capacitors with tea waste derived activated carbon electrodes and plastic crystal based flexible gel polymer electrolytes

    Science.gov (United States)

    Suleman, M.; Deraman, M.; Othman, M. A. R.; Omar, R.; Hashim, M. A.; Basri, N. H.; Nor, N. S. M.; Dolah, B. N. M.; Hanappi, M. F. Y. M.; Hamdan, E.; Sazali, N. E. S.; Tajuddin, N. S. M.; Jasni, M. R. M.

    2016-08-01

    We report a novel configuration of symmetrical electric double-layer capacitors (EDLCs) comprising a plastic crystalline succinonitrile (SN) based flexible polymer gel electrolyte, incorporated with sodium trifluoromethane sulfonate (NaTf) immobilised in a host polymer poly (vinylidine fluoride-co-hexafluoropropylene) (PVdF-HFP). The cost-effective activated carbon powder possessing a specific surface area (SSA) of ~ 1700 m2g-1 containing a large proportion of meso-porosity has been derived from tea waste to use as supercapacitor electrodes. The high ionic conductivity (~3.6×10-3 S cm-1 at room temperature) and good electrochemical stability render the gel polymer electrolyte film a suitable candidate for the fabrication of EDLCs. The performance of the EDLCs has been tested by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and galvanostatic charge-discharge studies. The performance of the EDLC cell is found to be promising in terms of high values of specific capacitance (~270 F g-1), specific energy (~ 36 Wh kg-1), and power density (~ 33 kW kg-1).

  6. Preparation of organic/inorganic composite membranes using two types of polymer matrix via a sol-gel process

    Science.gov (United States)

    Park, Seung-Hee; Park, Jin-Soo; Yim, Sung-Dae; Park, Seok-Hee; Lee, Young-Moo; Kim, Chang-Soo

    Organic/inorganic composite membranes were prepared using two different polymers. BPO 4 particles were introduced into polymers via an in situ sol-gel process. Pre-/post-sulfonated polymers were used to prepare composite membranes as matrix. Pre-sulfonated poly(aryl ether ketone) (SPAEK-6F) copolymer was synthesized via nucleophilic aromatic substitution. Degree of sulfonation was adjusted by the percentage of sulfonated monomer. Post-sulfonated poly(ether ether ketone) (SPEEK) was prepared using concentrated sulfuric acid as sulfonation agent. The membranes were characterized in terms of the ion-exchange capacity (IEC), proton conductivity, water uptake, AFM, SEM and their thermal properties. The SPAEK-6F plain membranes showed higher proton conductivity than that of the SPEEK plain membranes at similar water uptake or IEC due to their structural difference. SEM images of the composite membranes showed that the BPO 4 particles were homogenously dispersed in the polymer matrices and BPO 4 particle size was greatly influenced by polymer matrix. The SPAEK-6F/BPO 4 composite membranes had much smaller BPO 4 particle size than the SPEEK/BPO 4 composite membranes due to well dispersion of BPO 4 sol-like particulates in SPAEK-6F polymer solutions forming more hydrophobic/hydrophilic nanophase than SPEEK polymer solutions. The latter containing a few micrometer-scale BPO 4 particles showed higher proton conductivity than the former containing hundreds nanometer-scale BPO 4 particles at similar water uptake due to the increase in freezable water and effect of particle size.

  7. Direct Evidence for Percolation of Immobilized Polymer Layer around Nanoparticles Accounting for Sol-Gel Transition in Fumed Silica Dispersions.

    Science.gov (United States)

    Zheng, Zhong; Song, Yihu; Yang, Ruiquan; Zheng, Qiang

    2015-12-22

    Immobilized polymer fractions have been claimed to be of vital importance for sol-gel transitions generally observed in nanoparticle dispersions but remain a matter of debate regarding mechanism and difficulty for prediction. Here we investigate the immobilized layer structures of trifunctionality polyether polyol (PPG) near the surfaces of hydrophilic and hydrophobic fumed silica (FS) nanoparticles to reveal the role of surface chemistry on the molecular dynamics and sol-gel transitions of the dispersions. Using modulated differential scanning calorimetry, we measure the specific heat capacity during glass transition and the enthalpy during cold-crystallization. Comparing with hydrophobic FS that forms a fully immobilized (glassy) layer, we find that hydrophilic FS immobilizes more PPG, forming a partially immobilized outer layer being unable to crystallize next to the inner glassy layer. By correlating the thickness of the glassy layer with half of the minimum spacing between nanoparticles, we directly evidence the percolation of this layer along the nearest neighbor nanoparticles responsible for the sol-gel transition. Using effective volume fraction including the glassy layer, we successfully construct master curves of relative viscosity of both hydrophilic and hydrophobic FS dispersions, pointing to a common sol-gel transition mechanism mediated by the surface chemistry.

  8. Does nitrogen gas bubbled through a low density polymer gel dosimeter solution affect the polymerization process?

    Directory of Open Access Journals (Sweden)

    Daryoush Shahbazi-Gahrouei

    2015-01-01

    Conclusion: It appeared that reactions between gelatin-free radicals and monomers, due to an increase in the gel temperature during rotation in the household mixer, led to a higher R 2 -background response. In the second type of gel, it seemed that the collapse of the nitrogen bubbles was the main factor that affected the R 2 -responses.

  9. Preliminary study of MAGAT polymer gel dosimetry for boron-neutron capture therapy

    Science.gov (United States)

    Hayashi, Shin-ichiro; Sakurai, Yoshinori; Uchida, Ryohei; Suzuki, Minoru; Usui, Shuji; Tominaga, Takahiro

    2015-01-01

    MAGAT gel dosimeter with boron is irradiated in Heavy Water Neutron Irradiation Facility (HWNIF) of Kyoto University Research Reactor (KUR). The cylindrical gel phantoms are exposed to neutron beams of three different energy spectra (thermal neutron rich, epithermal and fast neutron rich and the mixed modes) in air. Preliminary results corresponding to depth-dose responses are obtained as the transverse relaxation rate (R2=1/T2) from magnetic resonance imaging data. As the results MAGAT gel dosimeter has the higher sensitivity on thermal neutron than on epi-thermal and fast neutron, and the gel with boron showed an enhancement and a change in the depth-R2 response explicitly. From these results, it is suggested that MAGAT gel dosimeter can be an effective tool in BNCT dosimetry.

  10. A COMPARISON OF CLINICAL PERFORMANCE OF I-GEL WITH PROSEAL LMA IN PATIENTS UNDERGOING MASTECTOMY

    Directory of Open Access Journals (Sweden)

    Basheer Padinhare Madathil

    2016-04-01

    Full Text Available AIM To assess the ease of insertion of I-gel and ProSeal LMA and incidence of post op complications. Study design-A prospective randomised controlled trial comparing the clinical performance of I-gel and ProSeal LMA. METHODS After induction and good muscle relaxation LMA/I-gel was introduced as per randomised computer allocation. After insertion, nasogastric tube was inserted through the gastric channel. Parameters monitored were heart rate, nubp, SpO2, ETCO2 at 1, 5 minutes after insertion of the device and thereafter every 5 minutes till the end of surgery. In case of failure, airway was secured with an endotracheal tube. Ease of gastric tube insertion was noted at the end of surgery; postop complications were noted. Blood staining of the device, injury to the lips, teeth, and tongue were noted. Incidence of sore throat 24 hrs. after surgery was also noted. Statistical analysis was done with SPSS software. RESULTS Age, height, weight and BMI were comparable in both groups. The airway characteristics was also comparable in both the groups. Ease of introduction was also the same for both the groups, but the time taken was much lesser for I-gel group. The ease of insertion of gastric tube was much easier for the I-gel group. Blood staining of the device was more with the ProSeal LMA group. There was no injury to any of the structures mentioned above. Postop sore throat was more in the ProSeal LMA group. CONCLUSION From our study, we conclude that the airway can be secured much faster with I-gel than ProSeal LMA. Postop sore throat was much less for I-gel than ProSeal LMA. Both were comparable in number of attempts of insertion, gastric tube introduction. Trauma to the airway structures was also minimum with both I-gel and ProSeal LMA.

  11. Terbinafine hydrochloride nanovesicular gel: In vitro characterization, ex vivo permeation and clinical investigation.

    Science.gov (United States)

    AbdelSamie, Sara M; Kamel, Amany O; Sammour, Omaima A; Ibrahim, Shady M

    2016-06-10

    In this work, nanovesicular chitosan gels were prepared for dermal delivery of terbinafine hydrochloride (TBN HCl). Ethosomes and vesicles containing different types of penetration enhancers (PEs) viz. Terpenes (cineole and limonene), labrasol and transcutol were developed. The prepared vesicles were evaluated for physical characteristics as well as skin interaction. The selected vesicles were incorporated into chitosan gel. An in vivo animal study was done on rat induced superficial Candida infection model. Moreover, randomized double blind clinical study was done on patients to compare the effect of the selected nanovesicular gel against the market product. Results showed the formation of nearly spherical, mostly deformable vesicular systems with size range of 95.5-530nm, zeta potential range of -0.1 to 15mV and entrapment efficiency range of 20-96.7%. Penetration enhancer vesicles (PEVs) prepared with 4% limonene (ELI4) showed the highest percent of drug deposition in the skin (53%) and the highest local accumulation efficiency value (35.3). In vivo animal study showed that the lowest fungal burden produced with ELI4 chitosan gel. Clinical studies showed cure rate of 86% within 7days treatment in case of limonene nanovesicular gel compared to 20% for market product (Lamisil® cream). PMID:27072432

  12. Quasi-solid-state nanocrystalline TiO2 solar cells using gel network polymer electrolytes based on polysiloxanes

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A quasi-solid-state dye-sensitized nanocrystalline porous TiO2 film solar cell was fabricated using a novel gel network polymer electrolyte based on polysiloxanes with both polyethylene oxide internal plasticized side chains and quaternary ammonium groups. The cell exhibited better photoelectrical conversion performance under 60 mW/cm2 irradiation. The short photocurrent (Isc) of 5.0 mA/cm2 and open voltage (Voc) of 0.68 V were achieved, and the energy conversion efficiency (η) and fill factor (ff) were 3.4% and 0.60, respectively.

  13. Artificial Neural Network and Response Surface Methodology Modeling in Ionic Conductivity Predictions of Phthaloylchitosan-Based Gel Polymer Electrolyte

    Directory of Open Access Journals (Sweden)

    Ahmad Danial Azzahari

    2016-01-01

    Full Text Available A gel polymer electrolyte system based on phthaloylchitosan was prepared. The effects of process variables, such as lithium iodide, caesium iodide, and 1-butyl-3-methylimidazolium iodide were investigated using a distance-based ternary mixture experimental design. A comparative approach was made between response surface methodology (RSM and artificial neural network (ANN to predict the ionic conductivity. The predictive capabilities of the two methodologies were compared in terms of coefficient of determination R2 based on the validation data set. It was shown that the developed ANN model had better predictive outcome as compared to the RSM model.

  14. A composite membrane based on a biocompatible cellulose as a host of gel polymer electrolyte for lithium ion batteries

    Science.gov (United States)

    Xiao, S. Y.; Yang, Y. Q.; Li, M. X.; Wang, F. X.; Chang, Z.; Wu, Y. P.; Liu, X.

    2014-12-01

    A composite polymer membrane is prepared by coating poly(vinylidene fluoride) (PVDF) on the surface of a membrane based on methyl cellulose (MC) which is environmentally friendly and cheap. Its characteristics are investigated by scanning electron microscopy, FT-IR, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The outer PVDF layers are porous which results in high electrolyte uptake and the lithium ion transference number is much larger than that of the pure MC. Moreover, the cell based on Li//LiFePO4 delivers high discharge capacity and good rate behavior in the range of 4.2-2.5 V when the composite membrane is used as the separator and the host of a gel polymer electrolyte, lithium as the counter and reference electrode, and LiFePO4 as cathode. The obtained results suggest that this unique composite membrane shows great attraction in the lithium ion batteries with high safety and low cost.

  15. Colloidal interactions of inorganic nanoparticles grafted with zwitterionic polymer brushes and gels by surface-mediated seeded polymerization.

    Science.gov (United States)

    An, Soyoun; Choi, Sang Koo; Cho, Jang Woo; Kim, Hyun Tae; Kim, Jin Woong

    2014-08-01

    A robust and straightforward approach is introduced to synthesize inorganic nanoparticles chemically grafted with a zwitterionic poly(2-methacryroyloxyethylphosphorylcholine) (PMPC) thin layers. The synthesis method is based on the surface-mediated seeded polymerization. In order to observe how the polymer chain architectures affect colloidal interactions, the zinc oxide nanoparticles are grafted with linear brushes and with a thin hydrogel layer, respectively. The thickness of PMPC shell layers spans a few nanometers. The studies on suspension rheology for the nanoparticles show that the nanoparticles with PMPC brushes show the stronger repulsive force than those with the PMPC gel shell due to the entropic stabilization. When the shear force is applied to the Pickering emulsion produced by assembly of the nanoparticles, it is noticeable that the presence of PMPC brushes on the particles rather enhances the drop-to-drop attraction, which presumably stems from the entanglement of polymer chains between the contacted interfacial planes of the emulsion droplets during shearing.

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

    Directory of Open Access Journals (Sweden)

    Sathiya Raj

    2016-03-01

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

  17. Organic-inorganic Polymer Nano-hybrids Based on Sol-gel Reaction

    Institute of Scientific and Technical Information of China (English)

    Yoshiki; Chujo

    2007-01-01

    1 Results Nano-ordered composite materials consisting of organic polymers and inorganic materials have been attracting attention for the purpose of the creation of high-performance or high-functional polymeric materials. Especially,the word of "polymer hybrid" claims the blends of organic and inorganic components at nano-level dispersion. By using this idea,an enhancement of mechanical strength of organic polymers with silica particles is possible.High transparency of this material is another important ...

  18. A novel stability-enhanced lithium-oxygen battery with cellulose-based composite polymer gel as the electrolyte

    International Nuclear Information System (INIS)

    Highlights: • A novel cellulose-based composite polymer gel electrolyte (PGE) membrane is prepared. • PGE exhibits excellent ionic conductivity and electrochemical stability. • PEG reduces the penetration of oxygen to lithium anode and electrolyte loss. • Non-aqueous Li/O2 battery employing PGE membrane displays good cyclic stability. - Abstract: A novel lithium-oxygen (Li-O2) battery with a polymer gel electrolyte (PGE) membrane is successfully prepared. The membrane is a blend of cellulose acetate (CA) and poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) and is fabricated using a solution casting technique followed by impregnation with lithium bis(trifluoromethane sulfonimide) (LiTFSI) solution. We demonstrate that the PGE membrane has good electrolyte uptake and shows high ionic conductivity as well as excellent thermal and electrochemical stability. A Li-O2 battery containing our PGE as the electrolyte and separator exhibits good rate capability and enhanced cycling capacity retention compared to a battery using commercial liquid electrolyte and a polyethylene (PE) separator under the same conditions. We attribute this enhanced performance to the PGE, which maybe restrain the diffusion of oxygen from the air cathode to the Li metal anode. This study may prove valuable for resolving the problem of poor cycling stability in Li-O2 batteries caused by oxygen diffusion from cathode to anode

  19. SYNTHESIS AND OPTICAL PROPERTIES OF A NOVEL ORGANIC/INORGANIC HYBRID NONLINEAR OPTICAL POLYMER VIA SOL-GEL PROCESS

    Institute of Scientific and Technical Information of China (English)

    Hong-xia Xi; Zhong Li; Zhao-xi Liang

    2001-01-01

    A new organic/inorganic hybrid nonlinear optical (NLO) material was developed by the sol-gel process of an alkoxysilane dye with tetraethoxysilane. A NLO moiety based on 4-nitro-4′-hydroxy azobenzene was covalently bonded to the triethoxysilane derivative, i.e. γ-isocyanatopropyl triethoxysilane. The preparation process and properties of the sol-gel derived NLO polymer were studied and characterized by SEM, FTIR, 1H-NMR, UV-Vis, DSC and second harmonic generation (SHG) measurement. The results indicated that the chemical bonding of the chromophores to the inorganic SiO2 networks induces Iow dipole alignment relaxation and preferable orientational stability. The SHG measurements also showed that the bonded polymer film containing 75 wt% of the akoxysilane dye has a high electro-optic coefficient (r33) of7. 1 pm/V at 1.1 μm wavelength, and exhibit good SHG stability, the r33 values can maintain about 92.7% of its initial value at room temperature for 90 days, and can maintain about 59.3% at 100℃ for 300 min.``

  20. Study of hafnium (IV) oxide nanoparticles synthesized by polymerized complex and polymer precursor derived sol-gel methods

    KAUST Repository

    Ramos-González, R.

    2010-03-01

    This work reports the preparation and characterization of hafnium (IV) oxide (HfO2) nanoparticles grown by derived sol-gel routes that involves the formation of an organic polymeric network. A comparison between polymerized complex (PC) and polymer precursor (PP) methods is presented. For the PC method, citric acid (CA) and ethylene glycol (EG) are used as the chelating and polymerizable reagents, respectively. In the case of PP method, poly(acrylic acid) (PAA) is used as the chelating reagent. In both cases, different precursor gels were prepared and the hafnium (IV) chloride (HfCl4) molar ratio was varied from 0.1 to 1.0 for the PC method and from 0.05 to 0.5 for the PP method. In order to obtain the nanoparticles, the precursors were heat treated at 500 and 800 °C. The thermal characterization of the precursor gels was carried out by thermogravimetric analysis (TGA) and the structural and morphological characterization by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD patterns of the samples obtained by both methods shows the formation of HfO2 at 500 °C with monoclinic crystalline phase. The PC method exhibited also the cubic phase. Finally, the HfO2 nanoparticles size (4 to 11 nm) was determined by TEM and XRD patterns. © (2010) Trans Tech Publications.

  1. MRI-based polymer gel dosimetry for validating plans with multiple matrices in Gamma Knife stereotactic radiosurgery.

    Science.gov (United States)

    Gopishankar, N; Watanabe, Yoichi; Subbiah, Vivekanandhan

    2011-01-31

    One of treatment planning techniques with Leksell GammaPlan (LGP) for Gamma Knife stereotactic radiosurgery (GKSRS) uses multiple matrices with multiple dose prescriptions. Computational complexity increases when shots are placed in multiple matrices with different grid sizes. Hence, the experimental validation of LGP calculated dose distributions is needed for those cases. For the current study, we used BANG3 polymer gel contained in a head-sized glass bottle to simulate the entire treatment process of GKSRS. A treatment plan with three 18 mm shots and one 8 mm shot in separate matrices was created with LGP. The prescribed maximum dose was 8 Gy to three shots and 16 Gy to one of the 18 mm shots. The 3D dose distribution recorded in the gel dosimeter was read using a Siemens 3T MRI scanner. The scanning parameters of a CPMG pulse sequence with 32 equidistant echoes were as follows: TR = 7 s, echo step = 13.6 ms, field-of-view = 256 mm × 256 mm, and pixel size = 1 mm × 1 mm. Interleaved acquisition mode was used to obtain 15 to 45 2-mm-thick slices. Using a calibration relationship between absorbed dose and the spin-spin relaxation rate (R2), we converted R2 images to dose images. MATLAB-based in-house programs were used for R2 estimation and dose comparison. Gamma-index analysis for the 3D data showed gamma values less than unity for 86% of the voxels. Through this study we accomplished the first application of polymer gel dosimetry for a true comparison between measured 3D dose distributions and LGP calculations for plans using multiple matrices for multiple targets.

  2. Clinical utility of transdermal delivery of oxybutynin gel via a metered-dose pump in the management of overactive bladder

    Directory of Open Access Journals (Sweden)

    Wagg A

    2012-11-01

    Full Text Available Adrian WaggDepartment of Medicine, University of Alberta, Edmonton, Alberta, CanadaAbstract: Oxybutynin is an efficacious treatment for overactive bladder, but its clinical utility is hampered by relative intolerability due to its side effect profile. Over the last few years, various attempts to enhance the tolerability of oxybutynin by varying the drug delivery mechanism have been introduced and have included extended release, rectal suppository, transdermal patch, and gel formulations. The recent introduction of a transdermal oxybutynin gel in a sachet form has been complemented by the administration of gel in a metered dose pump. This paper reviews the available evidence for transdermal oxybutynin gel and, where it exists, for the pump-based gel. The clinical utility of the pump-based gel is discussed.Keywords: urgency incontinence, overactive bladder, oxybutynin, transdermal

  3. High-temperature solvent stability of sol-gel germania triblock polymer coatings in capillary microextraction on-line coupled to high-performance liquid chromatography.

    Science.gov (United States)

    Segro, Scott S; Malik, Abdul

    2010-09-10

    Germania-based sol-gel organic-inorganic hybrid coatings were prepared for on-line coupling of capillary microextraction with high-performance liquid chromatography. For this, a germania-based sol-gel precursor, tetra-n-butoxygermane and a hydroxy-terminated triblock copolymer, poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) were used. These sol-gel germania triblock polymer coatings were chemically anchored to the inner walls of a fused silica capillary (0.25 mm I.D.) in course of its evolution from the sol solution. Scanning electron microscopy images of the sol-gel germania triblock polymer coating were obtained to estimate the coating thickness. For the first time, the analyte distribution constants between a sol-gel germania organic-inorganic hybrid coating and the samples (K(cs)) were determined. For a variety of analytes from different chemical classes, including polycyclic aromatic hydrocarbons (PAHs), ketones, alcohols, phenols and amines, the K(cs) values ranged from 8.1 x 10(1) to 5.6 x 10(4). Also, for the first time, the stability of the sol-gel germania-based coating in high-temperature reversed-phase solvent environment was evaluated. The sol-gel germania triblock polymer coatings were capable of surviving exposure to high-temperature solvent conditions (200 degrees C) with little change in extraction capabilities. This demonstrates that sol-gel germania triblock polymer hybrid materials might be suitable for further applications in high-temperature HPLC. The reproducibility of the method for preparation of the sol-gel germania triblock polymer coatings was also evaluated, and the capillary-to-capillary RSD values ranged from 5.3 to 6.5%. The use of higher flow rates in extraction was found to significantly reduce the time required (from 30-40 to 10-15 min) to reach equilibrium between the sol-gel germania triblock polymer coating and the analytes in the sample solution.

  4. Electrochemical characterizations on MnO2 supercapacitors with potassium polyacrylate and potassium polyacrylate-co-polyacrylamide gel polymer electrolytes

    KAUST Repository

    Lee, Kuang-Tsin

    2009-11-01

    MnO2·nH2O supercapacitors with potassium polyacrylate (PAAK) and potassium polyacrylate-co-polyacrylamide (PAAK-co-PAAM) gel polymer electrolytes (GPEs) having the weight compositions of polymer:KCl:H2O = 9%:6.7%:84.3% have been characterized for their electrochemical performance. Compared with the liquid electrolyte (LE) counterpart, the GPE cells exhibit remarkable (∼50-130%) enhancement in specific capacitance of the oxide electrode, and the extent of the enhancement increases with increasing amount of the carboxylate groups in the polymers as well as with increasing oxide/electrolyte interfacial area. In situ X-ray absorption near-edge structure (XANES) analysis indicates that the oxide electrodes of the GPE cells possess higher Mn-ion valences and are subjected to greater extent of valence variation than that of the LE cell upon charging/discharging over the same potential range. Copolymerization of PAAK with PAAM greatly improves the cycling stability of the MnO2·nH2O electrode, and the improvement is attributable to the alkaline nature of the amino groups. Both GPEs exhibit ionic conductivities greater than 1.0 × 10-1 S cm-1 and are promising for high-rate applications. © 2009 Elsevier Ltd. All rights reserved.

  5. Preparation and characterization of PAN–KI complexed gel polymer electrolytes for solid-state battery applications

    Indian Academy of Sciences (India)

    N KRISHNA JYOTHI; K K VENKATARATNAM; P NARAYANA MURTY; K VIJAYA KUMAR

    2016-08-01

    The free standing and dimensionally stable gel polymer electrolyte films of polyacrylonitrile (PAN): potassium iodide (KI) of different compositions, using ethylene carbonate as a plasticizer and dimethyl formamide as solvent, are prepared by adopting ‘solution casting technique’ and these films are examined for their conductivities. The structural, miscibility and the chemical rapport between PAN and KI are investigated using X-ray diffraction, Fourier transform infrared spectroscopy and differential scanning calorimetry methods. The conductivity is enhanced with the increase in KI concentration and temperature. The maximum conductivity at 30$^{\\circ}$C is found to be $2.089 \\times 10^{−5}$ S cm$^{−1}$ for PAN:KI (70:30) wt%, which is nine orders greater than that of pure PAN (${\\lt}10^{−14}$ S cm$^{−1}$). The conductivity-temperature dependence of these polymer electrolyte films obeys Arrhenius behaviour with activation energy ranging from 0.358 to 0.478 eV. The conducting carriers of charge transport in these polymer electrolyte films are identified by Wagner’s polarization technique and it is found that the charge transport is predominantlydue to ions. The better conducting sample is used to fabricate the battery with configuration K/PAN $+$ KI/I$_2$ $+$ C $+$ electrolyte and good discharge characteristics of battery are observed.

  6. Verification of dose volume histograms in stereotactic radiosurgery and radiotherapy using polymer gel and MRI

    Science.gov (United States)

    Šemnická, Jitka; Novotný, Josef, Jr.; Spěváček, Václav; Garčic, Jirí; Steiner, Martin; Judas, Libor

    2006-12-01

    In this work we focus on dose volume histograms (DVHs) measurement in stereotactic radiosurgery (SR) performed with the Leksell gamma knife (ELEKTA Instrument AB, Stockholm, Sweden) and stereotactic radiotherapy (SRT) performed with linear accelerator 6 MV Varian Clinac 2100 C/D (Varian Medical Systems, Palo Alto, USA) in conjunction with BrainLAB stereotactic system (BrainLAB, Germany) using modified BANG gel and magnetic resonance imaging (MRI). The aim of the experiments was to investigate a method for acquiring entire dose volume information from irradiated gel dosimeter and calculate DVHs.

  7. RapidArc treatment verification in 3D using polymer gel dosimetry and Monte Carlo simulation

    DEFF Research Database (Denmark)

    Ceberg, Sofie; Gagne, Isabel; Gustafsson, Helen;

    2010-01-01

    and MC simulations, thus investigating any discrepancy between the planned dose delivery and the actual delivery. Additionally, the reproducibility of the delivery was investigated using repeated gel measurements. A prostate treatment plan was delivered to a 1.3 liter nPAG gel phantom using one single...... was within 2.5% (1SD). A 3D gamma analysis between the dose matrices were carried out using gamma criteria 3%/3 mm and 5%/5 mm (% dose difference and mm distance to agreement) within the volume enclosed by the 50% isodose surface (VOI50) and the 90% isodose surface (VOI90), respectively. All comparisons...

  8. Experimental and theoretical investigation of time-setting polymer gels in porous media

    International Nuclear Information System (INIS)

    This paper comprises studies of the kinetics of the xanthan/chromium gel system. The central objective of this work is to perform well-characterized core flow experiments with a simple gelling system that may then be mathematically simulated to obtain a detailed knowledge of the processes that are occurring. Gamma-labeled /sup 51/Cr is used so that in-situ chromium profiles may be observed during gel emplacement. These are required to distinguish between different kinetic/transport models because effluent profiles alone are insufficient for this purpose. A generalized multicomponent transport equation including terms describing the crosslinking reaction is used to simulate the experiments

  9. Note: Utilization of polymer gel as a bolus compensator and a dosimeter in the near-surface buildup region for breast-conserving therapy

    Energy Technology Data Exchange (ETDEWEB)

    Fuse, Hiraku, E-mail: fuseh@ipu.ac.jp; Inohira, Masaya; Kawamura, Hiraku; Fujisaki, Tatsuya [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Inashiki-gun, Ibaraki 300-0331 (Japan); Shinoda, Kazuya [Graduate School of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ibaraki (Japan); Department of Radiological Technology, Tsukuba Medical Center Hospital, Tsukuba (Japan); Miyamoto, Katsumi [Department of Radiological Technology, Tsukuba Medical Center Hospital, Tsukuba (Japan); Sakae, Takeji [Faculty of Medicine, University of Tsukuba, Tsukuba (Japan)

    2015-09-15

    Tangential beam radiotherapy is routinely used for radiation therapy after breast conserving surgery. A tissue-equivalent bolus placed on the irradiated area shifts the depth of the dose distribution; this bolus provides uniform dose distribution to the breast. The gel bolus made by the BANG-Pro{sup ®} polymer gel and in an oxygen non-transmission pack was applicable as a dosimeter to measure dose distribution in near-surface buildup region. We validated the use of the gel bolus to improve in the whole-breast/chest wall, including the near-surface buildup region.

  10. Tomotherapy dose distribution verification using MAGIC-f polymer gel dosimetry

    International Nuclear Information System (INIS)

    Purpose: This paper presents the application of MAGIC-f gel in a three-dimensional dose distribution measurement and its ability to accurately measure the dose distribution from a tomotherapy unit. Methods: A prostate intensity-modulated radiation therapy (IMRT) irradiation was simulated in the gel phantom and the treatment was delivered by a TomoTherapy equipment. Dose distribution was evaluated by the R2 distribution measured in magnetic resonance imaging. Results: A high similarity was found by overlapping of isodoses of the dose distribution measured with the gel and expected by the treatment planning system (TPS). Another analysis was done by comparing the relative absorbed dose profiles in the measured and in the expected dose distributions extracted along indicated lines of the volume and the results were also in agreement. The gamma index analysis was also applied to the data and a high pass rate was achieved (88.4% for analysis using 3%/3 mm and of 96.5% using 4%/4 mm). The real three-dimensional analysis compared the dose-volume histograms measured for the planning volumes and expected by the treatment planning, being the results also in good agreement by the overlapping of the curves. Conclusions: These results show that MAGIC-f gel is a promise for tridimensional dose distribution measurements.

  11. Tomotherapy dose distribution verification using MAGIC-f polymer gel dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Pavoni, J. F.; Pike, T. L.; Snow, J.; DeWerd, L.; Baffa, O. [Departamento de Fisica, Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto-Universidade de Sao Paulo, Av. Bandeirantes, 3900 - CEP 14040-901 - Bairro Monte Alegre - Ribeirao Preto, SP (Brazil); Medical Radiation Research Center, Department of Medical Physics, University of Wisconsin, 1111 Highland Avenue, B1002 WIMR, Madison, Wisconsin 53705-2275 (United States); Departamento de Fisica, Faculdade de Filosofia Ciencias e Letras de Ribeirao Preto-Universidade de Sao Paulo, Av. Bandeirantes, 3900 - CEP 14040-901 - Bairro Monte Alegre - Ribeirao Preto, SP (Brazil)

    2012-05-15

    Purpose: This paper presents the application of MAGIC-f gel in a three-dimensional dose distribution measurement and its ability to accurately measure the dose distribution from a tomotherapy unit. Methods: A prostate intensity-modulated radiation therapy (IMRT) irradiation was simulated in the gel phantom and the treatment was delivered by a TomoTherapy equipment. Dose distribution was evaluated by the R2 distribution measured in magnetic resonance imaging. Results: A high similarity was found by overlapping of isodoses of the dose distribution measured with the gel and expected by the treatment planning system (TPS). Another analysis was done by comparing the relative absorbed dose profiles in the measured and in the expected dose distributions extracted along indicated lines of the volume and the results were also in agreement. The gamma index analysis was also applied to the data and a high pass rate was achieved (88.4% for analysis using 3%/3 mm and of 96.5% using 4%/4 mm). The real three-dimensional analysis compared the dose-volume histograms measured for the planning volumes and expected by the treatment planning, being the results also in good agreement by the overlapping of the curves. Conclusions: These results show that MAGIC-f gel is a promise for tridimensional dose distribution measurements.

  12. A green and environment-friendly gel polymer electrolyte with higher performances based on the natural matrix of lignin

    Science.gov (United States)

    Gong, Sheng-Dong; Huang, Yun; Cao, Hai-Jun; Lin, Yuan-Hua; Li, Yang; Tang, Shui-Hua; Wang, Ming-Shan; Li, Xing

    2016-03-01

    In order to explore one truly green and environment-friendly gel polymer electrolyte (GPE), the natural biopolymer of lignin is firstly all over the world used as matrix to prepare GPE. The electrolyte membrane based on lignin can be easily fabricated just with lignin, liquid electrolyte and distilled water. Through comprehensive investigation of obtained GPE, it is found that the liquid electrolyte uptake reaches up to 230 wt.%; before 100 °C, GPE does not lose any weight and is thermal stable; at room temperature the ion conductivity is 3.73 mS cm-1; the amazing property of lithium ion transference number is high up to 0.85; GPE expresses complete electrochemical stability before 7.5 V and favorable compatibility with lithium anode; the outstanding cell performance of C-rate and cycle capacity. All these remarkably excellent performances endow lignin with application potential in GPE used in lithium ion batteries (LIBs) with higher performances.

  13. Structure and biological response of polymer/silica nanocomposites prepared by sol-gel technique

    OpenAIRE

    Vallés-Lluch, A.; COSTA, E.; Ferrer, G. Gallego; Pradas, M. Monleón; Salmerón-Sánchez, M.

    2010-01-01

    Abstract Structure of P(EMA-co-HEA)/SiO2 nanocomposites with silica content in the range from 0 to 30 %wt was correlated with cell behaviour on substrates of those compositions by making use of two different populations of primary human cells: articular cartilage chondrocytes and dental pulp cells. Substrates were prepared by the simultaneous copolymerization of the organic monomers and the sol-gel reaction of the silica precursor in different proportions, which led to weight fract...

  14. Multi-responsive physical gels formed by a biosynthetic asymmetric triblock protein polymer and a polyanion

    NARCIS (Netherlands)

    Pham, T.H.T.; Wang, J.; Werten, M.W.T.; Snijkers, F.; Wolf, de F.A.; Cohen Stuart, M.A.; Gucht, van der J.

    2013-01-01

    We report the design, production and characterization of a biosynthetic asymmetric triblock copolymer which consists of one collagen-like and one cationic block spaced by a hydrophilic random coiled block. The polymer associates into micelles when a polyanion is added due to the electrostatic intera

  15. High performance of transferring lithium ion for polyacrylonitrile-interpenetrating crosslinked polyoxyethylene network as gel polymer electrolyte.

    Science.gov (United States)

    Kuo, Ping-Lin; Wu, Ching-An; Lu, Chung-Yu; Tsao, Chin-Hao; Hsu, Chun-Han; Hou, Sheng-Shu

    2014-03-12

    A polyacrylonitrile (PAN)-interpenetrating cross-linked polyoxyethylene (PEO) network (named XANE) was synthesized acting as separator and as gel polymer electrolytes simultaneously. SEM images show that the surface of the XANE membrane is nonporous, comparing to the surface of the commercial separator to be porous. This property results in excellent electrolyte uptake amount (425 wt %), and electrolyte retention for XANE membrane, significantly higher than that of commercial separator (200 wt %). The DSC result indicates that the PEO crystallinity is deteriorated by the cross-linked process and was further degraded by the interpenetration of the PAN. The XANE membrane shows significantly higher ionic conductivity (1.06-8.21 mS cm(-1)) than that of the commercial Celgard M824 separator (0.45-0.90 mS cm(-1)) ascribed to the high electrolyte retention ability of XANE (from TGA), the deteriorated PEO crystallinity (from DSC) and the good compatibility between XANE and electrode (from measuring the interfacial-resistance). For battery application, under all charge/discharge rates (from 0.1 to 3 C), the specific half-cell capacities of the cell composed of the XANE membrane are all higher than those of the aforementioned commercial separator. More specifically, the cell composed of the XANE membrane has excellent cycling stability, that is, the half-cell composed of the XANE membrane still exhibited more than 97% columbic efficiency after 100 cycles at 1 C. The above-mentioned advantageous properties and performances of the XANE membrane allow it to act as both an ionic conductor as well as a separator, so as to work as separator-free gel polymer electrolytes. PMID:24521309

  16. Sol-Gel Material-Enabled Electro-Optic Polymer Modulators.

    Science.gov (United States)

    Himmelhuber, Roland; Norwood, Robert A; Enami, Yasufumi; Peyghambarian, Nasser

    2015-07-27

    Sol-gels are an important material class, as they provide easy modification of material properties, good processability and are easy to synthesize. In general, an electro-optic (EO) modulator transforms an electrical signal into an optical signal. The incoming electrical signal is most commonly information encoded in a voltage change. This voltage change is then transformed into either a phase change or an intensity change in the light signal. The less voltage needed to drive the modulator and the lower the optical loss, the higher the link gain and, therefore, the better the performance of the modulator. In this review, we will show how sol-gels can be used to enhance the performance of electro-optic modulators by allowing for designs with low optical loss, increased poling efficiency and manipulation of the electric field used for driving the modulator. The optical loss is influenced by the propagation loss in the device, as well as the losses occurring during fiber coupling in and out of the device. In both cases, the use of sol-gel materials can be beneficial due to the wide range of available refractive indices and low optical attenuation. The influence of material properties and synthesis conditions on the device performance will be discussed.

  17. Investigation of a 2D two-point maximum entropy regularization method for signal-to-noise ratio enhancement: application to CT polymer gel dosimetry

    International Nuclear Information System (INIS)

    This study presents a new method of image signal-to-noise ratio (SNR) enhancement by utilizing a newly developed 2D two-point maximum entropy regularization method (TPMEM). When utilized as an image filter, it is shown that 2D TPMEM offers unsurpassed flexibility in its ability to balance the complementary requirements of image smoothness and fidelity. The technique is evaluated for use in the enhancement of x-ray computed tomography (CT) images of irradiated polymer gels used in radiation dosimetry. We utilize a range of statistical parameters (e.g. root-mean square error, correlation coefficient, error histograms, Fourier data) to characterize the performance of TPMEM applied to a series of synthetic images of varying initial SNR. These images are designed to mimic a range of dose intensity patterns that would occur in x-ray CT polymer gel radiation dosimetry. Analysis is extended to a CT image of a polymer gel dosimeter irradiated with a stereotactic radiation therapy dose distribution. Results indicate that TPMEM performs strikingly well on radiation dosimetry data, significantly enhancing the SNR of noise-corrupted images (SNR enhancement factors >15 are possible) while minimally distorting the original image detail (as shown by the error histograms and Fourier data). It is also noted that application of this new TPMEM filter is not restricted exclusively to x-ray CT polymer gel dosimetry image data but can in future be extended to a wide range of radiation dosimetry data

  18. Enhanced ultraviolet photocatalytic activity of Ag/ZnO nanoparticles synthesized by modified polymer-network gel method

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Y. H.; Xu, M., E-mail: hsuming-2001@aliyun.com [Southwest University for Nationalities, Key Laboratory of Information Materials of Sichuan Province, School of Electrical and Information Engineering (China); Xu, L. X. [Nanyang Technological University, Plasma Sources and Applications Center, NIE (Singapore); Zhang, C. L.; Zhang, Q. P.; Xu, X. N. [Southwest University for Nationalities, Key Laboratory of Information Materials of Sichuan Province, School of Electrical and Information Engineering (China); Xu, S. [Nanyang Technological University, Plasma Sources and Applications Center, NIE (Singapore); Ostrikov, K., E-mail: kostya.ostrikov@qut.edu.au [Queensland University of Technology, Institute for Future Environments and School of Chemistry, Physics, and Mechanical Engineering (Australia)

    2015-09-15

    Ag/ZnO nanoparticle (NP) heterostructures are synthesized through a modified polymer-network gel method in which glucose is added to the precursor solution to prevent the gel from drastically shrinking during drying of the aqueous solution. Structural and optical properties of the samples are characterized by a range of techniques including XRD, SEM, TEM, XPS, UV–Vis, and PL. The high-quality Ag-ZnO heterostructure is evidenced clearly by high-resolution TEM. The Ag/ZnO heterostructure nanocomposites exhibit a higher photocatalytic activity in the degradation of methyl orange than pure ZnO. Especially, Ag/ZnO NP heterostructures with the Ag/Zn molar ratio of 5:95 (sample ZA-5) show the highest degradation efficiency, which is 11 times higher compared with pure ZnO. The photoluminescence properties of the heterostructures and O defect states are studied to well explain the observed photocatalytic effects. ZA-5 also exhibits competitive photocatalytic activity for the degradation of other pollutant dyes such as Methylene blue and Rhodamine B compared with the recently reported techniques, while showing excellent catalyst photostability as well as offering simplicity and reliability.

  19. 3-V Solid-State Flexible Supercapacitors with Ionic-Liquid-Based Polymer Gel Electrolyte for AC Line Filtering.

    Science.gov (United States)

    Kang, Yu Jin; Yoo, Yongju; Kim, Woong

    2016-06-01

    State-of-the-art solid-state flexible supercapacitors with sufficiently fast response speed for AC line filtering application suffer from limited energy density. One of the main causes of the low energy density is the low cell voltage (1 V), which is limited by aqueous-solution-based gel electrolytes. In this work, we demonstrate for the first time a 3-V flexible supercapacitor for AC line filtering based on an ionic-liquid-based polymer gel electrolyte and carbon nanotube electrode material. The flexible supercapacitor exhibits an areal energy density that is more than 20 times higher than that of the previously demonstrated 1-V flexible supercapacitor (0.66 vs 0.03 μWh/cm(2)) while maintaining excellent capacitive behavior at 120 Hz. The supercapacitor shows a maximum areal power density of 1.5 W/cm(2) and a time constant of 1 ms. The improvement of the cell voltage while maintaining the fast-response capability greatly improves the potential of supercapacitors for high-frequency applications in wearable and/or portable electronics. PMID:27167760

  20. Effect of acid dopants in biodegradable gel polymer electrolyte and the performance in an electrochemical double layer capacitor

    Science.gov (United States)

    Sudhakar, Y. N.; Selvakumar, M.; Krishna Bhat, D.

    2015-09-01

    Proton-conducting biodegradable gellan gum gel polymer electrolytes (GPEs) have been prepared using three different dopants, namely ortho-phosphoric (o-H3PO4), sulfuric (H2SO4) and hydrochloric acids (HCl). The GPEs were cross-linked using borax. The polymeric gels were characterized by spectroscopic, thermal, ionic conductivities and dielectric measurements. Proton conductivity was in the range of 5.1 × 10-3 to 3.7 × 10-4 s cm-1 and activation energies were between 0.14 meV and 0.19 meV, at different temperatures. Among the doped acids, the H3PO4 doped GPE exhibited thermal stability at varying temperature. Electrochemical double layer capacitors (EDLCs) were fabricated using activated carbon as electrode material and GPEs. The EDLCs were tested using cyclic voltammetry, ac impedance spectroscopic and galvanostatic charge-discharge techniques. The maximum specific capacitance value was 146 F g-1 at a scan rate of 2 mV s-1. Quite stable values were obtained at a constant current density up to 1000 cycles.

  1. [Clinical observation on treatment of mycotic vaginitis with Sophora gel combined with Fluconazole capsules].

    Science.gov (United States)

    Wang, Na-mei; Cui, Lin; Ma, Chun-fen; Wang, Hui-xia

    2015-03-01

    Mycotic vaginitis is a common and frequently-occurring gynaecopathia and easy to attack repeatedly, so painful to patients. In this study, the authors observed the clinical efficacy of Sophora gel combined with Fluconazole capsules in treating mycotic vaginitis, in order to seek an effective method for treating mycotic vaginitis. Totally 85 patients with mycotic vaginitis treated in our hospital between December 2012 and July 2014 were randomly divided into the treatment group (43 patients) and the control group (42 patients). The treatment group was given vaginally Sophora gel (one piece every night for 14 days) and orally Fluconazole capsules (150 mg, once every three days, four times in total); The control group was only administered with Fluconazole capsules. The total efficacy, cure rate, recurrence rate and clinical symptom improvements of the two groups were observed. The results show that the total efficacy, the cure rate and the recurrence rate of the treatment group vs. the control group were respectively 97.7%, 90.7% and 2.6% vs. 83.3%, 71.4% and 20.0%, with statistical significance in their differences (P Fluconazole capsules can improve antifungal activity of drugs, relieve clinical symptoms, shorten the course of disease, enhance the cure rate and reduce the recurrence rate; So this therapy can be widely applied in clinic.

  2. An ion-imprinted polymer supported by attapulgite with a chitosan incorporated sol-gel process for selective separation of Ce(Ⅲ)

    Institute of Scientific and Technical Information of China (English)

    Chun Xiang Li; Jian Ming Pan; Jie Gao; Yong Sheng Yan; Gan Qing Zhao

    2009-01-01

    The surface ion-imprinting concept and chitosan incorporated sol-gel process were applied to the synthesis of a new attapulgite-supported polymer for selective separation of Ce(Ⅲ) from aqueous solution. The imprinting mechanism of prepared ion-imprinted polymer were discussed with the Characteristics of FT-IR and SEM. Results from the experiments of adsorption capacity and selectivity suggested that ion-imprinted polymer offered a fast kinetics for the adsorption of Ce(Ⅲ) under the optimum conditions. Its maximum adsorption capacity was 38.02 mg/g, and the selective recognition towards Ce(Ⅲ) was much higher than that of the non-imprinted polymer and attapulgite. The prepared functional polymer was shown to be promising for selective separation and enrichment of trace Ce(Ⅲ) in environmental samples.

  3. Assessment of the effects of CT dose in averaged x-ray CT images of a dose-sensitive polymer gel

    International Nuclear Information System (INIS)

    The signal-to-noise ratio achievable in x-ray computed tomography (CT) images of polymer gels can be increased by averaging over multiple scans of each sample. However, repeated scanning delivers a small additional dose to the gel which may compromise the accuracy of the dose measurement. In this study, a NIPAM-based polymer gel was irradiated and then CT scanned 25 times, with the resulting data used to derive an averaged image and a ''zero-scan'' image of the gel. Comparison between these two results and the first scan of the gel showed that the averaged and zero-scan images provided better contrast, higher contrast-to- noise and higher signal-to-noise than the initial scan. The pixel values (Hounsfield units, HU) in the averaged image were not noticeably elevated, compared to the zero-scan result and the gradients used in the linear extrapolation of the zero-scan images were small and symmetrically distributed around zero. These results indicate that the averaged image was not artificially lightened by the small, additional dose delivered during CT scanning. This work demonstrates the broader usefulness of the zero-scan method as a means to verify the dosimetric accuracy of gel images derived from averaged x-ray CT data

  4. Preparation and adsorption behavior of berberine hydrochloride imprinted polymers by using silica gel as sacrificed support material

    Science.gov (United States)

    Li, Hui; Li, Yuzhuo; Li, Zhiping; Peng, Xiyang; Li, Yanan; Li, Gui; Tan, Xianzhou; Chen, Gongxi

    2012-03-01

    Preparation of berberine hydrochloride (B-Cl) imprinted polymers (MIPs) based on surface imprinting technique with silica gel as sacrificial support material was performed successfully by using B-Cl as template, methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) as functional monomer and cross-linker, respectively. The prepared polymers were characterized by Fourier transmission infrared spectrometry (FTIR) and scanning electron microscopy (SEM). Adsorption behavior of the MIPs for the template and its structural analogues was investigated. Sites distribution on the surface of MIPs was explored by using different isotherm adsorption models and thermodynamic parameters for the adsorption of B-Cl on the MIPs determined. Sample application and reusability for the MIPs was also evaluated. Results indicated the strong adsorption and high selectivity of the MIPs for B-Cl. Saturated adsorption capacity reached 27.2 μmol g-1 and the selectivity coefficient of the MIPs for B-Cl relative to jatrorrhizine hydrochloride (J-Cl) and palmatine palmatus hydrochloride (P-Cl) are 3.70 and 6.03, respectively. In addition, the MIPs were shown with good reusability and selectively retention ability in sample application.

  5. Preparation and adsorption behavior of berberine hydrochloride imprinted polymers by using silica gel as sacrificed support material

    Energy Technology Data Exchange (ETDEWEB)

    Li Hui, E-mail: lihuijsdx@163.com [Key Laboratory of Plant Resource Conservation and Utilization, Jishou University, Hunan Jishou, 416000 (China); Li Yuzhuo [Key Laboratory of Plant Resource Conservation and Utilization, Jishou University, Hunan Jishou, 416000 (China); Li Zhiping [College of Chemistry and Chemical Engineering, Jishou University, Hunan Jishou, 416000 (China); Peng Xiyang; Li Yanan; Li Gui; Tan Xianzhou; Chen Gongxi [Key Laboratory of Plant Resource Conservation and Utilization, Jishou University, Hunan Jishou, 416000 (China)

    2012-03-01

    Preparation of berberine hydrochloride (B-Cl) imprinted polymers (MIPs) based on surface imprinting technique with silica gel as sacrificial support material was performed successfully by using B-Cl as template, methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) as functional monomer and cross-linker, respectively. The prepared polymers were characterized by Fourier transmission infrared spectrometry (FTIR) and scanning electron microscopy (SEM). Adsorption behavior of the MIPs for the template and its structural analogues was investigated. Sites distribution on the surface of MIPs was explored by using different isotherm adsorption models and thermodynamic parameters for the adsorption of B-Cl on the MIPs determined. Sample application and reusability for the MIPs was also evaluated. Results indicated the strong adsorption and high selectivity of the MIPs for B-Cl. Saturated adsorption capacity reached 27.2 {mu}mol g{sup -1} and the selectivity coefficient of the MIPs for B-Cl relative to jatrorrhizine hydrochloride (J-Cl) and palmatine palmatus hydrochloride (P-Cl) are 3.70 and 6.03, respectively. In addition, the MIPs were shown with good reusability and selectively retention ability in sample application.

  6. Field-theoretic model of inhomogeneous supramolecular polymer networks and gels.

    Science.gov (United States)

    Mohan, Aruna; Elliot, Richard; Fredrickson, Glenn H

    2010-11-01

    We present a field-theoretic model of the gelation transition in inhomogeneous reversibly bonding systems and demonstrate that our model reproduces the classical Flory-Stockmayer theory of gelation in the homogeneous limit. As an illustration of our model in the context of inhomogeneous gelation, we analyze the mean-field behavior of an equilibrium system of reacting trifunctional units in a good solvent confined within a slit bounded by parallel, repulsive walls. Our results indicate higher conversions and, consequently, higher concentrations of gel following the gelation transition near the center of the slit relative to the edges. PMID:21054065

  7. Oxidation increases mucin polymer cross-links to stiffen airway mucus gels.

    Science.gov (United States)

    Yuan, Shaopeng; Hollinger, Martin; Lachowicz-Scroggins, Marrah E; Kerr, Sheena C; Dunican, Eleanor M; Daniel, Brian M; Ghosh, Sudakshina; Erzurum, Serpel C; Willard, Belinda; Hazen, Stanley L; Huang, Xiaozhu; Carrington, Stephen D; Oscarson, Stefan; Fahy, John V

    2015-02-25

    Airway mucus in cystic fibrosis (CF) is highly elastic, but the mechanism behind this pathology is unclear. We hypothesized that the biophysical properties of CF mucus are altered because of neutrophilic oxidative stress. Using confocal imaging, rheology, and biochemical measures of inflammation and oxidation, we found that CF airway mucus gels have a molecular architecture characterized by a core of mucin covered by a web of DNA and a rheological profile characterized by high elasticity that can be normalized by chemical reduction. We also found that high levels of reactive oxygen species in CF mucus correlated positively and significantly with high concentrations of the oxidized products of cysteine (disulfide cross-links). To directly determine whether oxidation can cross-link mucins to increase mucus elasticity, we exposed induced sputum from healthy subjects to oxidizing stimuli and found a marked and thiol-dependent increase in sputum elasticity. Targeting mucin disulfide cross-links using current thiol-amino structures such as N-acetylcysteine (NAC) requires high drug concentrations to have mucolytic effects. We therefore synthesized a thiol-carbohydrate structure (methyl 6-thio-6-deoxy-α-D-galactopyranoside) and found that it had stronger reducing activity than NAC and more potent and fast-acting mucolytic activity in CF sputum. Thus, oxidation arising from airway inflammation or environmental exposure contributes to pathologic mucus gel formation in the lung, which suggests that it can be targeted by thiol-modified carbohydrates.

  8. Oxidation increases mucin polymer cross-links to stiffen airway mucus gels.

    Science.gov (United States)

    Yuan, Shaopeng; Hollinger, Martin; Lachowicz-Scroggins, Marrah E; Kerr, Sheena C; Dunican, Eleanor M; Daniel, Brian M; Ghosh, Sudakshina; Erzurum, Serpel C; Willard, Belinda; Hazen, Stanley L; Huang, Xiaozhu; Carrington, Stephen D; Oscarson, Stefan; Fahy, John V

    2015-02-25

    Airway mucus in cystic fibrosis (CF) is highly elastic, but the mechanism behind this pathology is unclear. We hypothesized that the biophysical properties of CF mucus are altered because of neutrophilic oxidative stress. Using confocal imaging, rheology, and biochemical measures of inflammation and oxidation, we found that CF airway mucus gels have a molecular architecture characterized by a core of mucin covered by a web of DNA and a rheological profile characterized by high elasticity that can be normalized by chemical reduction. We also found that high levels of reactive oxygen species in CF mucus correlated positively and significantly with high concentrations of the oxidized products of cysteine (disulfide cross-links). To directly determine whether oxidation can cross-link mucins to increase mucus elasticity, we exposed induced sputum from healthy subjects to oxidizing stimuli and found a marked and thiol-dependent increase in sputum elasticity. Targeting mucin disulfide cross-links using current thiol-amino structures such as N-acetylcysteine (NAC) requires high drug concentrations to have mucolytic effects. We therefore synthesized a thiol-carbohydrate structure (methyl 6-thio-6-deoxy-α-D-galactopyranoside) and found that it had stronger reducing activity than NAC and more potent and fast-acting mucolytic activity in CF sputum. Thus, oxidation arising from airway inflammation or environmental exposure contributes to pathologic mucus gel formation in the lung, which suggests that it can be targeted by thiol-modified carbohydrates. PMID:25717100

  9. Polyelectrolyte gels

    Energy Technology Data Exchange (ETDEWEB)

    Segalman, D.J.; Witkowski, W.R.

    1995-06-01

    Polyelectrolyte (PE) gels are swollen polymer/solvent networks that undergo a reversible volume collapse/expansion through various types of stimulation. Applications that could exploit this large deformation and solvent expulsion/absorption characteristics include robotic {open_quotes}fingers{close_quotes} and drug delivery systems. The goals of the research were to first explore the feasibility of using the PE gels as {open_quotes}smart materials{close_quotes} - materials whose response can be controlled by an external stimulus through a feedback mechanism. Then develop a predictive capability to simulate the dynamic behavior of these gels. This involved experimentally characterizing the response of well-characterized gels to an applied electric field and other stimuli to develop an understanding of the underlying mechanisms which cause the volume collapse. Lastly, the numerical analysis tool was used to simulate various potential engineering devices based on PE gels. This report discusses the pursuit of those goals through experimental and computational means.

  10. Dual phase polymer gel electrolyte based on non-woven poly(vinylidenefluoride-co-hexafluoropropylene)–layered clay nanocomposite fibrous membranes for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Shubha, Nageswaran [School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798 (Singapore); Prasanth, Raghavan [School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798 (Singapore); Energy Research Institute - NTU (ERI-N) Research Techno Plaza, 50 Nanyang Drive, Singapore 637553 (Singapore); TUM-CREATE Center for Electromobility, Nanyang Technological University, Singapore 637553 (Singapore); Hoon, Hng Huey [School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798 (Singapore); Srinivasan, Madhavi, E-mail: madhavi@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798 (Singapore); Energy Research Institute - NTU (ERI-N) Research Techno Plaza, 50 Nanyang Drive, Singapore 637553 (Singapore); TUM-CREATE Center for Electromobility, Nanyang Technological University, Singapore 637553 (Singapore)

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► P(VdF-co-HFP)–clay nanocomposite based electrospun membranes are prepared. ► The membranes are used as polymer gel electrolyte (PGE) in lithium ion batteries. ► The composite PGE shows ionic conductivity of 5.5 mS cm{sup −1} at room temperature. ► Li/PGE/LiFePO{sub 4} cell delivers initial discharge capacity of 160 mAh g{sup −1}. ► The use of prepared electrolyte significantly improved the cell performance. -- Abstract: A new approach for fabricating polymer gel electrolytes (PGEs) based on electrospun poly(vinylidenefluoride-co-hexafluoropropylene) (P(VdF-co-HFP)) incorporated with layered nanoclay has been employed to enhance the ionic conductivity and electrochemical properties of P(VdF-co-HFP) without compromising its mechanical strength. The effect of layered nanoclay on properties of membranes has been evaluated by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Surface morphology of the membranes has been studied using field-emission scanning electron microscopy (FE-SEM). Polymer gel electrolytes are prepared by soaking the fibrous membrane into 1 M LiPF{sub 6} in EC/DEC. The electrochemical studies show that incorporation of layered nanoclay into the polymer matrix greatly enhanced the ionic conductivity and compatibility with lithium electrodes. The charge–discharge properties and cycling performance of Li/LiFePO{sub 4} cells comprising nanocomposite polymer gel electrolytes have been evaluated at room temperature.

  11. Bioinspired design of a polymer gel sensor for the realization of extracellular Ca2+ imaging

    Science.gov (United States)

    Ishiwari, Fumitaka; Hasebe, Hanako; Matsumura, Satoko; Hajjaj, Fatin; Horii-Hayashi, Noriko; Nishi, Mayumi; Someya, Takao; Fukushima, Takanori

    2016-04-01

    Although the role of extracellular Ca2+ draws increasing attention as a messenger in intercellular communications, there is currently no tool available for imaging Ca2+ dynamics in extracellular regions. Here we report the first solid-state fluorescent Ca2+ sensor that fulfills the essential requirements for realizing extracellular Ca2+ imaging. Inspired by natural extracellular Ca2+-sensing receptors, we designed a particular type of chemically-crosslinked polyacrylic acid gel, which can undergo single-chain aggregation in the presence of Ca2+. By attaching aggregation-induced emission luminogen to the polyacrylic acid as a pendant, the conformational state of the main chain at a given Ca2+ concentration is successfully translated into fluorescence property. The Ca2+ sensor has a millimolar-order apparent dissociation constant compatible with extracellular Ca2+ concentrations, and exhibits sufficient dynamic range and excellent selectivity in the presence of physiological concentrations of biologically relevant ions, thus enabling monitoring of submillimolar fluctuations of Ca2+ in flowing analytes containing millimolar Ca2+ concentrations.

  12. Utility of colposcopy in a phase 2 portion of a microbicide clinical trial of BufferGel and 0.5% PRO 2000 Gel

    Directory of Open Access Journals (Sweden)

    Zvavahera M Chirenje

    2012-08-01

    Full Text Available Background: The majority of new HIV infections are acquired through heterosexual transmission. There is urgent need for prevention methods to compliment behavior change and condom use. Topical microbicide represent a potential strategy for reduction of HIV transmission in women. Methods: Monthly Colposcopy evaluations were performed during pelvic examinations among 299 women enrolled in the Phase 2 portion of HPTN 035 study at four sites (1 in USA, 3 in Southern Africa. This was a phase 2/2b, multisite, randomized, and controlled clinical trial with four arms: BufferGel, 0.5% PRO2000 Gel, placebo gel and no gel. At two of the sites, pelvic examinations were conducted by the use of naked eye without colposcopy. Results: A colposcopy finding of any kind was detected in 48% of participants at baseline compared to 40% at 3 months (p =0.04. The lower rates were also observed in vaginal discharge (22% at baseline, 16% at 3 months, p=0.06, erythema (15% at baseline, 8% at 3 months, p=0.004. The trend towards significance at p=0.05 disappear when utilizing stringent statistical significance levels. A pelvic finding of any kind was detected in 71% of colposcopy participants compared to 41% of participants who had naked eye examination only conducted at two sites that performed both colposcopy and naked eye without colposcopy. Use of colposcopy yielded significantly higher rates of participants with deep epithelial disruption, erythema and ecchymosis. We observed no cases of incident Chlamydia, Gonorrhea, or Syphilis during the three month follow up. There were 2 cases of incident HIV during 3-month study period neither of which was associated with any abnormal colposcopy evaluation findings. Conclusion: No safety signals were observed in the 4 study arms, allowing seamless transition from phase 2 to 2b. Colposcopy utility in microbicide clinical trials has minimal value given high rates of background noise findings of no relevant clinical significance.

  13. Hierarchical self-assembly of telechelic star polymers: from soft patchy particles to gels and diamond crystals

    Science.gov (United States)

    Capone, Barbara; Coluzza, Ivan; Blaak, Ronald; Lo Verso, Federica; Likos, Christos N.

    2013-09-01

    The design of self-assembling materials in the nanometer scale focuses on the fabrication of a class of organic and inorganic subcomponents that can be reliably produced on a large scale and tailored according to their vast applications for, e.g. electronics, therapeutic vectors and diagnostic imaging agent carriers, or photonics. In a recent publication (Capone et al 2012 Phys. Rev. Lett. 109 238301), diblock copolymer stars have been shown to be a novel system, which is able to hierarchically self-assemble first into soft patchy particles and thereafter into more complex structures, such as the diamond and cubic crystal. The self-aggregating single star patchy behavior is preserved from extremely low up to high densities. Its main control parameters are related to the architecture of the building blocks, which are the number of arms (functionality) and the fraction of attractive end-monomers. By employing a variety of computational and theoretical tools, ranging from the microscopic to the mesoscopic, coarse-grained level in a systematic fashion, we investigate the crossover between the formation of microstructure versus macroscopic phase separation, as well as the formation of gels and networks in these systems. We finally show that telechelic star polymers can be used as building blocks for the fabrication of open crystal structures, such as the diamond or the simple-cubic lattice, taking advantage of the strong correlation between single-particle patchiness and lattice coordination at finite densities.

  14. pH-Mediated Fluorescent Polymer Particles and Gel from Hyperbranched Polyethylenimine and the Mechanism of Intrinsic Fluorescence.

    Science.gov (United States)

    Liu, Shi Gang; Li, Na; Ling, Yu; Kang, Bei Hua; Geng, Shuo; Li, Nian Bing; Luo, Hong Qun

    2016-02-23

    We report that fluorescence properties and morphology of hyperbranched polyethylenimine (hPEI) cross-linked with formaldehyde are highly dependent on the pH values of the cross-linking reaction. Under acidic and neutral conditions, water-soluble fluorescent copolymer particles (CPs) were produced. However, under basic conditions, white gels with weak fluorescence emission would be obtained. The water-soluble hPEI-formaldehyde (hPEI-F) CPs show strong intrinsic fluorescence without the conjugation to any classical fluorescent agents. By the combination of spectroscopy and microscopy techniques, the mechanism of fluorescence emission was discussed. We propose that the intrinsic fluorescence originates from the formation of a Schiff base in the cross-linking process between hPEI and formaldehyde. Schiff base bonds are the fluorescence-emitting moieties, and the compact structure of hPEI-F CPs plays an important role in their strong fluorescence emission. The exploration on fluorescence mechanism may provide a new strategy to prepare fluorescent polymer particles. In addition, the investigation shows that the hPEI-F CPs hold potential as a fluorescent probe for the detection of copper ions in aqueous media. PMID:26829461

  15. Poly(vinyl Alcohol) Borate Gel Polymer Electrolytes Prepared by Electrodeposition and Their Application in Electrochemical Supercapacitors.

    Science.gov (United States)

    Jiang, Mengjin; Zhu, Jiadeng; Chen, Chen; Lu, Yao; Ge, Yeqian; Zhang, Xiangwu

    2016-02-10

    Gel polymer electrolytes (GPEs) have been studied for preparing flexible and compact electrochemical energy storage devices. However, the preparation and use of GPEs are complex, and most GPEs prepared through traditional methods do not have good wettability with the electrodes, which retard them from achieving their performance potential. In this study, these problems are addressed by conceiving and implementing a simple, but effective, method of electrodepositing poly(vinyl alcohol) potassium borate (PVAPB) GPEs directly onto the surfaces of active carbon electrodes for electrochemical supercapacitors. PVAPB GPEs serve as both the electrolyte and the separator in the assembled supercapacitors, and their scale and shape are determined solely by the geometry of the electrodes. PVAPB GPEs have good bonding to the active electrode materials, leading to excellent and stable electrochemical performance of the supercapacitors. The electrochemical performance of PVAPB GPEs and supercapacitors can be manipulated simply by adjusting the concentration of KCl salt used during the electrodeposition process. With a 0.9 M KCl concentration, the as-prepared supercapacitors deliver a specific capacitance of 65.9 F g(-1) at a current density of 0.1 A g(-1) and retain more than 95% capacitance after 2000 charge/discharge cycles at a current density of 1 A g(-1). These supercapacitors also exhibit intelligent high voltage self-protection function due to the electrolysis-induced cross-linking effect of PVAPB GPEs. PMID:26788748

  16. Increasing the Mechanical Strength of Block Polymer Ion Gels Through the Stepwise Self-Assembly of a Thermoresponsive ABC Triblock Terpolymer

    Science.gov (United States)

    Hall, Cecilia; Zhou, Can; Danielsen, Scott; Lodge, Timothy

    Blends of network-forming block polymers and ionic liquids have remarkable potential for solid electrolytes, as they allow the combination of desirable mechanical and electrical properties. While ABA triblock copolymers have successfully been implemented as the network component of ion gels, these networks contain looped defects, where the endblocks of the polymer loop back into the same spherical core instead of forming a bridge between two cores. We demonstrate that the ABC triblock terpolymer poly(ethylene-alt-propylene)-block-poly(ethylene oxide)-block-poly(N-isopropylacrylamide) (PEP-b-PEO-b-PNIPAm) in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide forms a thermoreversible gel network with negligible looping defects. PEP-core micelles exist at all temperatures, while cooling causes association of the PNIPAm micelle corona to form a bridging network. Small-angle x-ray scattering and dynamic light scattering were used to characterize the high-temperature micelles. These gels show enhanced mechanical properties and the ability to form gels at lower concentrations than the corresponding thermoresponsive ABA triblock copolymers.

  17. Gel electrolytes based on poly(acrylonitrile)/sulpholane with hybrid TiO2/SiO2 filler for advanced lithium polymer batteries

    International Nuclear Information System (INIS)

    Highlights: • Paper describes properties of gel electrolyte based on PAN with TMS and TiO2-SiO2. • The TiO2-SiO2 oxide composite was precipitated in the emulsion system and used as the fillers. • The capacity of the graphite anode depends on the current rate and the amount of TiO2-SiO2. • For PE3 electrolyte was obtained practical capacity more than 90% of the theoretical capacity. - Abstract: This paper describes the synthesis and properties of a new type of ceramic fillers for composite polymer gel electrolytes. Hybrid TiO2-SiO2 ceramic powders have been obtained by co-precipitation from titanium(IV) sulfate solution using sodium silicate as the precipitating agent. The resulting submicron-size powders have been applied as fillers for composite polymer gel electrolytes for Li-ion batteries based on polyacrylonitrile (PAN) membranes. The powders and gel electrolytes have been examined structurally and electrochemically, showing favorable properties in terms of electrolyte uptake and electrochemical characteristics in Li-ion cells

  18. A novel application of normoxic polymer gel dosimeters for near real-time dose measurement using cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Tung-Hsin; Tsai, Chia-Jung [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taiwan (China); Zhang, Geoffrey [Department of Radiation Oncology, Moffitt Cancer Center, FL (United States); Yu, Chun-Yen; Liang, Ji-An [Department of Radiation Oncology, China Medical University Hospital, Taiwan (China); Wu, Jay [Department of Radiological Technology, Central Taiwan University of Science and Technology, Taiwan (China); Lee, Jason JS. [Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taiwan (China); Ho, Yung-Jen, E-mail: d9600@mail.cmuh.org.tw [Department of Biomedical Imaging and Radiological Science, China Medical University, Taiwan (China); Huang, Tzung-Chi, E-mail: tzungchi.huang@mail.cmu.edu.tw [Department of Biomedical Imaging and Radiological Science, China Medical University, Taiwan (China)

    2011-05-15

    The aim of this study is to evaluate the feasibility of using cone-beam CT system as a near real-time measurement device in dose estimation with normoxic polymer gel dosimetry (MAG). Each vial was filled with MAG gel and irradiated with uniform doses of 0-10 Gy to generate dose response curves. After irradiation, a cone-beam CT was used to perform the 3D dose measurement. In this study, two groups of gel samples were irradiated and measured in two ways for comparison: near real-time measurement, in which the gel phantom was read right after the irradiation, and delayed measurement, in which the measurement was performed 30 min, 4 h and 1 day after the irradiation for the gel phantom to be exposed to oxygen. All groups were also performed with and without a full bowtie filter to estimate the influence of a full bowtie filter to dose response. The linear dose response curves with and without a full bowtie filter for the four different CT imaging times were within a range 0.044-0.049{Delta}N{sub CT} cGy{sup -1} and 0.061-0.063{Delta}N{sub CT} cGy{sup -1}, respectively, with no significant difference at different imaging times. Nevertheless, dose response curves with the full bowtie filter were higher than those without, with p-value <0.05 for all the different imaging times tested. Normoxic polymer gel dosimetry combined with cone-beam CT provides a useful method for near real-time dose measurement.

  19. Super-capacitive electro-chemical performance of polymer blend gel polymer electrolyte (GPE) in carbon-based electrical double-layer capacitors

    International Nuclear Information System (INIS)

    This study reports on the fabrication and comparative performance characteristics of a symmetrical electrical double-layer capacitor (EDLC) employed gel polymer electrolyte (GPE) assembled between carbon based electrodes. Three cells, A, B and C were fabricated using different composition of active materials (activated or porous carbon), binder (PVdF-HFP) and conductivity enhancer (super-P). The configuration of cell A: 0.9 porous carbon/0.1 PVdF-HFP, cell B: 0.45 activated carbon/0.45 porous carbon/0.1 PVdF-HFP and cell C: 0.8 activated carbon/0.1 super-P/0.1 PVdF-HFP. The GPE, comprising a poly(vinyl pyrrolidone) (PVP)/poly(vinylidene fluoride co-hexafluoroproplyne) (PVdF-HFP) blend complexed with magnesium triflate, Mg(CF3SO3)2, was prepared by the solution casting technique at 60 °C. The physico-chemical properties of the GPEs were characterized by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), linear sweep voltammetry (LSV) and cyclic voltammetry (CV). The ionic conductivity at the ambient temperature of the GPE is 2.16 × 10−4 S cm−1 at 7.5 wt.% of Mg(CF3SO3)2 with a ∼2.6 V electro-chemical stability window. At the 1000th cycle, the specific capacitance, Cs of cell A is 89 F g−1 while cell B and C are 63 and 49 F g−1. Cell A shows excellent long-term cyclic stability (less than a 5% decrease in specific capacitance after 1000 cycles). The best operating voltage for cell A is 1.6 V with the specific capacitance 106 F g−1 after 500 cycles

  20. A Gel-Polymer Sn-C/LiMn0.5Fe0.5PO4 Battery Using a Fluorine-Free Salt.

    Science.gov (United States)

    Di Lecce, Daniele; Fasciani, Chiara; Scrosati, Bruno; Hassoun, Jusef

    2015-09-30

    Safety and environmental issues, because of the contemporary use of common liquid electrolytes, fluorinated salts, and LiCoO2-based cathodes in commercial Li-ion batteries, might be efficiently mitigated by employing alternative gel-polymer battery configurations and new electrode materials. Herein we study a lithium-ion polymer cell formed by combining a LiMn0.5Fe0.5PO4 olivine cathode, prepared by simple solvothermal pathway, a nanostructured Sn-C anode, and a LiBOB-containing PVdF-based gel electrolyte. The polymer electrolyte, here analyzed in terms of electrochemical stability by impedance spectroscopy (EIS) and voltammetry, reveals full compatibility for cell application. The LiBOB electrolyte salt and the electrochemically delithiaded Mn0.5Fe0.5PO4 have a higher thermal stability compared to conventional LiPF6 and Li0.5CoO2, as confirmed by thermogravimetric analysis (TGA) and by galvanostatic cycling at high temperature. LiMn0.5Fe0.5PO4 and Sn-C, showing in lithium half-cell a capacity of about 120 and 350 mAh g(-1), respectively, within the gelled electrolyte configuration are combined in a full Li-ion polymer battery delivering a stable capacity of about 110 mAh g(-1), with working voltage ranging from 2.8 to 3.6 V. PMID:26348604

  1. Fabrication of TiO{sub 2} {mu}-donuts by sol-gel spin coating using a polymer mask

    Energy Technology Data Exchange (ETDEWEB)

    Saleema, N. [Atmospheric Icing Engineering of Power Networks (CIGELE) and Atmospheric Icing of Power Network Equipment (INGIVRE), Universite du Quebec a Chicoutimi, 555 Blvd. University, Quebec, G7H 2B1 (Canada)], E-mail: snoormoh@uqac.ca; Farzaneh, M. [Atmospheric Icing Engineering of Power Networks (CIGELE) and Atmospheric Icing of Power Network Equipment (INGIVRE), Universite du Quebec a Chicoutimi, 555 Blvd. University, Quebec, G7H 2B1 (Canada); Paynter, R.W. [INRS, Centre Energie Materiaux Telecommunications, 1650 Boulevard Lionel-Boulet, Varennes, Quebec, J3X 1S2 (Canada)

    2009-03-15

    TiO{sub 2} {mu}-donuts have been fabricated on glass and silicon substrates using polymer masks in combination with a sol-gel technique. Cylindrical poly(methyl methacrylate) (PMMA) nanopillars have been created using a composite polymer of polystyrene (PS) and PMMA followed by careful removal of the PS. Atomic force microscopy (AFM) analyses show that the height and diameter of the PMMA cylinders used as the mask are 440 {+-} 5 nm and 2.1 {+-} 0.2 {mu}m, respectively. The cylindrical PMMA nanopillars have been coated with the sol of the TiO{sub 2} precursor by a spin coating technique and annealed in air at elevated temperature to remove the PMMA mask. Removal of the PMMA mask has resulted in the formation of well ordered {mu}-donuts of TiO{sub 2} on silicon surfaces. The interior and exterior heights of the TiO{sub 2} {mu}-donuts are found to be 373 {+-} 152 nm and 457 {+-} 136 nm, respectively; and the interior and exterior diameters of the TiO{sub 2} {mu}-donuts are found to be 1.33 {+-} 0.63 {mu}m and 2.82 {+-} 0.50 {mu}m, respectively. X-ray photoelectron spectroscopy (XPS) spectra of the TiO{sub 2} {mu}-donuts as well as the smooth TiO{sub 2} thin film showed signals from Ti and O confirming the presence of TiO{sub 2} with Ti 2p{sub 3/2} and O 1s peaks at 458.8 eV and 530.4 eV, respectively. The O 1s peak of the TiO{sub 2} {mu}-donuts shows another peak at binding energy 532.0 eV due to SiO{sub 2}, as during annealing, the PMMA evaporates and the Si substrate is exposed. The X-ray diffractometer (XRD) pattern of the smooth TiO{sub 2} thin film indicates that the anatase phase is present, with the characteristic peaks observed at 2{theta} values of 25.4{sup o}, 37.4{sup o}, and 48{sup o} corresponding to (1 0 1), (0 0 4), and (2 0 0) planes, respectively. UV-vis absorption spectra of TiO{sub 2} {mu}-donuts on glass showed an unusual absorption of light in the visible region at {approx}524 nm in addition to the usual UV absorption at {approx}337 nm.

  2. Transport Phenomena in Gel

    Directory of Open Access Journals (Sweden)

    Masayuki Tokita

    2016-05-01

    Full Text Available Gel becomes an important class of soft materials since it can be seen in a wide variety of the chemical and the biological systems. The unique properties of gel arise from the structure, namely, the three-dimensional polymer network that is swollen by a huge amount of solvent. Despite the small volume fraction of the polymer network, which is usually only a few percent or less, gel shows the typical properties that belong to solids such as the elasticity. Gel is, therefore, regarded as a dilute solid because its elasticity is much smaller than that of typical solids. Because of the diluted structure, small molecules can pass along the open space of the polymer network. In addition to the viscous resistance of gel fluid, however, the substance experiences resistance due to the polymer network of gel during the transport process. It is, therefore, of importance to study the diffusion of the small molecules in gel as well as the flow of gel fluid itself through the polymer network of gel. It may be natural to assume that the effects of the resistance due to the polymer network of gel depends strongly on the network structure. Therefore, detailed study on the transport processes in and through gel may open a new insight into the relationship between the structure and the transport properties of gel. The two typical transport processes in and through gel, that is, the diffusion of small molecules due to the thermal fluctuations and the flow of gel fluid that is caused by the mechanical pressure gradient will be reviewed.

  3. Randomized clinical trial comparing abluminal biodegradable polymer sirolimus-eluting stents with durable polymer sirolimus-eluting stents

    Science.gov (United States)

    Zhang, Haijun; Wang, Xiangfei; Deng, Wei; Wang, Shenguo; Ge, Junbo; Toft, Egon

    2016-01-01

    Abstract Background: The biodegradable polymer drug-eluting stents (DES) were developed to improve vascular healing. However, further data and longer-term follow-up are needed to confirm safety and efficacy of these stents. This randomized clinical trial aimed to compare safety and efficacy of 2 sirolimus-eluting stents (SES): Cordimax—a novel abluminal biodegradable polymer SES and Cypher Select—a durable polymer SES, at 9 months angiographic and 5-year clinical follow-up. Methods: We randomized 402 patients with coronary artery disease to percutaneous coronary intervention with Cordimax (n = 202) or Cypher select (n = 200). Angiographic follow-up was performed at 9 months after the index procedure and clinical follow-up annually up to 5 years. The primary endpoint was angiographic in-stent late luminal loss (LLL). Secondary endpoints included angiographic restenosis rate, target vessel revascularization (TVR), and major adverse cardiac events (MACEs; defined as cardiac death, myocardial infarction, or TVR) at 5-year follow-up. Results: Cordimax was noninferior to Cypher select for in-stent LLL (0.25 ± 0.47 vs 0.18 ± 0.49 mm; P = 0.587) and in-stent mean diameter stenosis (22.19 ± 12.21% vs 19.89 ± 10.79%; P = 0.064) at 9 months angiographic follow-up. The MACE rates were not different at 1 year (5.9% vs 4.0%, P = 0.376); however, MACE rates from 2 to 5 years were lower in the Cordimax group (6.8% vs 13.1%; P = 0.039). Conclusion: Abluminal biodegradable polymer SES is noninferior to durable polymer SES at 9-month angiographic and 1-year clinical follow-up. However, MACE rates from 2 to 5 years were less in the abluminal biodegradable polymer group. PMID:27661023

  4. SU-E-T-70: Commissioning a Multislice CT Scanner for X-Ray CT Polymer Gel Dosimetry

    International Nuclear Information System (INIS)

    Purpose: To commission a multislice computed tomography (CT) scanner for fast and reliable readout of radiation therapy (RT) dose distributions using CT polymer gel dosimetry (PGD). Methods: Commissioning was performed for a 16-slice CT scanner using images acquired through a 1L cylinder filled with water. Additional images were collected using a single slice machine for comparison purposes. The variability in CT number associated with the anode heel effect was evaluated and used to define a new slice-by-slice background image subtraction technique. Image quality was assessed for the multislice system by comparing image noise and uniformity to that of the single slice machine. The consistency in CT number across slices acquired simultaneously using the multislice detector array was also evaluated. Finally, the variability in CT number due to increasing x-ray tube load was measured for the multislice scanner and compared to the tube load effects observed on the single slice machine. Results: Slice-by-slice background subtraction effectively removes the variability in CT number across images acquired simultaneously using the multislice scanner and is the recommended background subtraction method when using a multislice CT system. Image quality for the multislice machine was found to be comparable to that of the single slice scanner. Further study showed CT number was consistent across image slices acquired simultaneously using the multislice detector array for each detector configuration of the slice thickness examined. In addition, the multislice system was found to eliminate variations in CT number due to increasing x-ray tube load and reduce scanning time by a factor of 4 when compared to imaging a large volume using a single slice scanner. Conclusion: A multislice CT scanner has been commissioning for CT PGD, allowing images of an entire dose distribution to be acquired in a matter of minutes. Funding support provided by the Natural Sciences and Engineering

  5. Evaluation of boronate-containing polymer brushes and gels as substrates for carbohydrate-mediated adhesion and cultivation of animal cells.

    Science.gov (United States)

    Ivanov, Alexander E; Kumar, Ashok; Nilsang, Suthasinee; Aguilar, Maria-Rosa; Mikhalovska, Lyubov I; Savina, Irina N; Nilsson, Lars; Scheblykin, Ivan G; Kuzimenkova, Marina V; Galaev, Igor Yu

    2010-02-01

    Boronate-containing thin polyacrylamide gels (B-Gel), polymer brushes (B-Brush) and chemisorbed organosilane layers (B-COSL) were prepared on the surface of glass slides and studied as substrates for carbohydrate-mediated cell adhesion. B-COSL- and B-Brush-modified glass samples exhibited multiple submicron structures densely and irregularly distributed on the glass surface, as found by scanning electron microscopy and atomic force microscopy. B-Gel was ca. 0.1 mm thick and contained pores with effective size of 1-2 microm in the middle and of 5-20 microm on the edges of the gel sample as found by confocal laser scanning microscopy. Evidence for the presence of phenylboronic acid in the samples was given by time-of-flight secondary ion mass-spectrometry (ToF SIMS), contact angle measurements performed in the presence of fructose, and staining with Alizarin Red S dye capable of formation specific, fluorescent complexes with boronic acids. A comparative study of adhesion and cultivation of animal cells on the above substrates was carried out using murine hybridoma M2139 cell line as a model. M2139 cells adhered to the substrates in the culture medium without glucose or sodium pyruvate at pH 8.0, and then were cultivated in the same medium at pH 7.2 for 4 days. It was found that the substrates of B-Brush type were superior both regarding cell adhesion and viability of the adhered cells, among the substrates studied. MTT assay confirmed proliferation of M2139 cells on B-Brush substrates. Some cell adhesion was also registered in the macropores of B-Gel substrate. The effects of surface microstructure of the boronate-containing polymers on cell adhesion are discussed. Transparent glass substrates grafted with boronate-containing copolymers offer good prospects for cell adhesion studies and development of cell-based assays. PMID:19837569

  6. Extended release microparticle-in-gel formulation of octreotide: Effect of polymer type on acylation of peptide during in vitro release.

    Science.gov (United States)

    Vaishya, Ravi D; Mandal, Abhirup; Patel, Sulabh; Mitra, Ashim K

    2015-12-30

    Polymeric microparticles (MPs)-in-gel formulations for extended delivery of octreotide were developed. We investigated influence of polymer composition on acylation of octreotide and kinetics of release during in vitro release from biodegradable polymeric formulations. Polycaprolactone (PCL), polylactic acid (PLA), polyglycolic acid (PGA) and polyethylene glycol (PEG) based triblock (TB≈PCL10k-PEG2k-PCL10k) and pentablock (PBA≈PLA3k-PCL7k-PEG2k-PCL7k-PLA3k and PBB≈PGA3k-PCL7k-PEG2k-PCL7k-PGA3k) polymers were investigated. Octreotide was encapsulated in MPs using methanol-oil/water emulsion solvent evaporation method. The particles were characterized for size, morphology, encapsulation efficiency, drug loading and in vitro release. Release samples were subjected to HPLC analysis for quantitation and HPLC-MS analysis for identification of native and chemically modified octreotide adducts. Entrapment efficiency of methanol-oil/water method with TB, PBA and PBB polymers were 45%, 60%, and 82%, respectively. A significant fraction of released octreotide was acylated from lactide and glycolide based PBA (53%) and PBB (92%) polymers. Substantial amount of peptide was not released from PBB polymers after 330 days of incubation. Complete release of octreotide was achieved from TB polymer over a period of 3 months with minimal acylation of peptide (13%). PCL based polymers resulted in minimal acylation of peptide and hence may be suitable for extended peptide and protein delivery. Conversely, polymers having PLA and PGA blocks may not be appropriate for peptide delivery due to acylation and incomplete release.

  7. Pityriasis versicolor: clinical experience with Lamisil cream and Lamisil DermGel.

    Science.gov (United States)

    Faergemann, J; Hersle, K; Nordin, P

    1997-01-01

    Pityriasis versicolor is a chronic superficial fungal disease usually located on the upper trunk, neck or upper arms. Terbinafine is an orally and topically active allylamine antifungal derivative with a broad antifungal spectrum. Several studies have documented the high activity of terbinafine (Lamisil) cream in the treatment of pityriasis versicolor, with cure rates of 79-100% after 2-4 weeks of treatment. Lamisil emulsion gel (Lamisil DermGel) is a new topical formulation that remains in the skin in high concentrations for several months after just 1 week of application. Recently, in a prospective, double-blind, placebo-controlled, randomised, parallel-group, comparative, multicentre study, we have treated patients with pityriasis versicolor with either terbinafine 1% emulsion gel (Lamisil DermGel) or placebo gel. Sixty-one patients were included, 31 in the Lamisil DermGel group and 30 in the placebo gel group. The gel was applied once daily for 7 days and the patients were followed up for 8 weeks. Twenty-eight patients in the active and 29 patients in the placebo group were evaluable for efficacy. Using the intent-to-treat efficacy analysis, 21/28 (75%) were cured in the Lamisil-DermGel-treated group compared to 4/29 (14%) in the placebo group. No side-effects were seen. In conclusion, Lamisil DermGel was well tolerated and superior to placebo in the treatment of pityriasis versicolor when applied once daily for 7 days.

  8. Clinical evaluation of topical application of perio-Q gel (Coenzyme Q 10 in chronic periodontitis patients

    Directory of Open Access Journals (Sweden)

    Mayank Hans

    2012-01-01

    Full Text Available Background and Objectives: Coenzyme Q 10 is a well studied antioxidant in medical literature, but studies regarding its efficacy in periodontal diseases are few. Hence, the aim of this study was to test the efficacy of coenzyme Q 10 in the form of gel (Perio-Q in patients with chronic gingivitis and periodontitis. Materials and Methods: A total of 12 patients were enrolled. A split mouth design was used for topical (extrasulcular application, intra-pocket application alone, intra-pocket application combined with scaling and root planing (SRP and SRP only in each quadrant, respectively. Clinical parameters such as plaque index, gingival index, gingival bleeding index, probing pocket depth, clinical attachment level were assessed at baseline, 3rd week, and 6th week. The results were subjected to statistical analysis, which were expressed as mean±SD and proportions as percentages. Intra group comparisons were made by paired t-test and one way analysis of variance (ANOVA for inter-group comparisons. Categorical data was analyzed by Fisher′s exact test. Results: The results showed on intra-group analysis significant reduction (P<0.01 of clinical parameters (plaque index (PI, gingival index (GI, gingival bleeding index (GBI, periodontal probing pocket depth (PPD, and clinical attachment level (CAL in all four treatment groups, whereas on inter-group analysis, intra-pocket gel application in combination with SRP showed significant reduction (P<0.05 for PI, GI, GBI, and CAL in comparison to intra-pocket gel alone. Interpretation and Conclusion: In the present study, in chronic periodontitis patients, sub-gingival mechanical debridement only and with Perio-Q gel showed almost similar clinical results without any statistically significant differences. Hence, it confirmed the primary role of basic mechanical approaches in periodontal therapy and did not provide enough clinical support for the superiority of adjunctive use of Perio-Q gel. However, it

  9. Water-compatible silica sol-gel molecularly imprinted polymer as a potential delivery system for the controlled release of salicylic acid.

    Science.gov (United States)

    Li, Bin; Xu, Jingjing; Hall, Andrew J; Haupt, Karsten; Tse Sum Bui, Bernadette

    2014-09-01

    Molecularly imprinted polymers (MIPs) for salicylic acid were synthesized and evaluated in aqueous environments in the aim to apply them as drug delivery carriers. One organic MIP and one inorganic MIP based on the sol-gel process were synthesized. The organic MIP was prepared by radical polymerization using the stoichiometric functional monomer, 1-(4-vinylphenyl)-3-(3,5-bis(trifluoromethyl)phenyl)urea, which can establish strong electrostatic interactions with the -COOH of salicylic acid. The sol-gel MIP was prepared with 3-(aminopropyl)triethoxysilane and trimethoxyphenylsilane, as functional monomers and tetraethyl orthosilicate as the crosslinker. While the organic MIPs bound the target specifically in acetonitrile, they exhibited lower binding in the presence of water, although the imprinting factor increased under these conditions, due to reduced non-specific binding. The sol-gel MIP has a high specificity and capacity for the drug in ethanol, a solvent compatible with drug formulation and biomedical applications. In vitro release profiles of the polymers in water were evaluated, and the results were modelled by Fick's law of diffusion and the power law. Analysis shows that the release mechanism was predominantly diffusion-controlled.

  10. Optical and energy dependent response of the alanine gel solution produced at IPEN to clinical photons and electrons beams

    International Nuclear Information System (INIS)

    The DL-Alanine (C3H7NO2) is an amino acid tissue equivalent traditionally used as standard dosimetric material in EPR dosimetry. Recently, it has been studied to be applied in gel dosimetry, considering that the addition of Alanine in the Fricke gel solution improves the production of ferric ions radiation induced. The spectrophotometric evaluation technique can be used comparing the two spectrum wavelengths bands: 457 nm band that corresponds to ferrous ions and 588 nm band that corresponds to ferric ions concentration to evaluate the dosimetric properties of this material. The performance of the Alanine gel solution developed at IPEN has been firstly studied using the spectrophotometric technique aiming to apply this material to 3D clinical doses evaluations using MRI technique. In this work, the optical and the energy dependent response of this solution submitted to clinical photons and electrons beams were studied. Different batches of gel solutions were prepared and maintained at low temperature during 12 h to solidification. Before irradiation, the samples were maintained during 1 h at room temperature. The photons and electrons irradiations were carried out using a Varian 2100C Medical Linear Accelerator of the Radiotherapy Department of the Hospital das Clinicas of the University of Sao Paulo with absorbed doses between 1 and 40 Gy; radiation field of 10 x 10 cm2; photon energies of 6 MeV and 15 MeV; and electron with energies between 6 and 15 MeV. The obtained results indicate that signal response dependence for clinical photons and electrons beams, to the same doses, for Alanine gel dosimeter is better than 3.6 % (1σ), and the energy dependence response, to the same doses, is better 3% (1σ) for both beams. These results indicate that the same calibration factor can be used and the optical response is energy independent in the studied dose range and clinical photons and electrons beams energies. (author)

  11. Optical and energy dependent response of the alanine gel solution produced at IPEN to clinical photons and electrons beams

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cleber F. [Faculdade Metodo de Sao Paulo (FAMESP), SP (Brazil). Radiologia; Campos, Leticia L. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The DL-Alanine (C{sub 3}H{sub 7}NO{sub 2}) is an amino acid tissue equivalent traditionally used as standard dosimetric material in EPR dosimetry. Recently, it has been studied to be applied in gel dosimetry, considering that the addition of Alanine in the Fricke gel solution improves the production of ferric ions radiation induced. The spectrophotometric evaluation technique can be used comparing the two spectrum wavelengths bands: 457 nm band that corresponds to ferrous ions and 588 nm band that corresponds to ferric ions concentration to evaluate the dosimetric properties of this material. The performance of the Alanine gel solution developed at IPEN has been firstly studied using the spectrophotometric technique aiming to apply this material to 3D clinical doses evaluations using MRI technique. In this work, the optical and the energy dependent response of this solution submitted to clinical photons and electrons beams were studied. Different batches of gel solutions were prepared and maintained at low temperature during 12 h to solidification. Before irradiation, the samples were maintained during 1 h at room temperature. The photons and electrons irradiations were carried out using a Varian 2100C Medical Linear Accelerator of the Radiotherapy Department of the Hospital das Clinicas of the University of Sao Paulo with absorbed doses between 1 and 40 Gy; radiation field of 10 x 10 cm{sup 2}; photon energies of 6 MeV and 15 MeV; and electron with energies between 6 and 15 MeV. The obtained results indicate that signal response dependence for clinical photons and electrons beams, to the same doses, for Alanine gel dosimeter is better than 3.6 % (1{sigma}), and the energy dependence response, to the same doses, is better 3% (1{sigma}) for both beams. These results indicate that the same calibration factor can be used and the optical response is energy independent in the studied dose range and clinical photons and electrons beams energies. (author)

  12. Molecular Typing of Acinetobacter Baumannii Clinical Strains in Tehran by Pulsed-Field Gel Electrophoresis

    Directory of Open Access Journals (Sweden)

    Neda Farahani

    2013-03-01

    Full Text Available Background & Objective : Currently, Acinetobacter baumannii is an important nosocomial pathogen insofar as its hospital outbreaks have been described from various geographical areas. Since the discrimination of strains within a species is important for delineating nosocomial outbreaks, this study was conducted with the aim of genotyping the A. baumannii clinical strains in Tehran via the pulsed-field gel electrophoresis (PFGE method, which is the most accurate method used for the typing of bacterial species.   Materials & methods: This study was performed on 70 isolates of acinetobacter baumannii isolated from patients from Baqiyatallah, Rasoole Akram, and Milad hospitals in Tehran. Cultural and biochemical methods were used for the identification of the isolates in species level, and then susceptibility tests were carried out on 50 isolates of A. baumannii using the disk diffusion method. The PFGE method was performed on the isolates by Apa I restriction enzyme. Finally, the results of the PFGE were analyzed. Result: Acinetobacter baumannii strains isolated from hospitals in Tehran showed seven different genetic patterns, two of which were sporadic . Also, genotypic profiles were different in each hospital, and different patterns of genetic resistance to common antibiotics were observed. Conclusion: A lthough diversity was observed among the strains of A. baumannii by the PFGE method in Tehran, no epidemic strains were found among them.  

  13. Sol-Gel Entrapped Levonorgestrel Antibodies: Activity and Structural Changes as a Function of Different Polymer Formats

    OpenAIRE

    Moran Shalev; Altstein Miriam

    2011-01-01

    The paper describes development of a sol-gel based immunoaffinity method for the steroid hormone levonorgestrel (LNG) and the effects of changes in the sol-gel matrix format on the activity of the entrapped antibodies (Abs) and on matrix structure. The best sol-gel format for Ab entrapment was found to be a tetramethoxysilane (TMOS) based matrix at a TMOS:water ratio of 1:8, containing 10% polyethylene glycol (PEG) of MW 0.4 kDa. Addition of higher percentages of PEG or a higher MW PEG did no...

  14. Inhibitory activity of Aloe vera gel on some clinically isolated cariogenic and periodontopathic bacteria.

    Science.gov (United States)

    Fani, Mohammadmehdi; Kohanteb, Jamshid

    2012-03-01

    Aloe vera is a medicinal plant with anti-inflammatory, antimicrobial, antidiabetic and immune-boosting properties. In the present study we investigated the inhibitory activities of Aloe vera gel on some cariogenic (Streptococcus mutans), periodontopathic (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis) and an opportunistic periodontopathogen (Bacteroides fragilis) isolated from patients with dental caries and periodontal diseases. Twenty isolates of each of these bacteria were investigated for their sensitivity to Aloe vera gel using the disk diffusion and microdilution methods. S. mutans was the species most sensitive to Aloe vera gel with a MIC of 12.5 µg/ml, while A. actinomycetemcomitans, P. gingivalis, and B. fragilis were less sensitive, with a MIC of 25-50 µg/ml (P Aloe vera gel at optimum concentration could be used as an antiseptic for prevention of dental caries and periodontal diseases.

  15. Effect of ozonated oil and chlorhexidine gel on plaque induced gingivitis: A randomized control clinical trial

    OpenAIRE

    Maya Sanjeev Indurkar; Renu Verma

    2016-01-01

    Background: Several chemotherapeutic agents have been developed to prevent gingivitis and its progression into periodontitis. In this present study, the efficacy of ozonated oil and chlorhexidine gel was assessed and compared on plaque induced gingivitis. Aim: To evaluate the effect of ozonated oil on plaque induced gingivitis and to compare its efficacy with chlorhexidine gel. Materials and Methods: A total of 20 subjects, aged from 18 to 65 years, with plaque-induced gingivitis were selecte...

  16. Adsorption characteristics, recognition properties, and preliminary application of nordihydroguaiaretic acid molecularly imprinted polymers prepared by sol-gel surface imprinting technology

    Science.gov (United States)

    Liao, Sen; Zhang, Wen; Long, Wei; Hou, Dan; Yang, Xuechun; Tan, Ni

    2016-02-01

    In this paper, a new core-shell composite of nordihydroguaiaretic acid (NDGA) molecularly imprinted polymers layer-coated silica gel (MIP@SiO2) was prepared through sol-gel technique and applied as a material for extraction of NDGA from Ephedra. It was synthesized using NDGA as the template molecule, γ-aminopropyltriethoxysilane (APTS) and methyltriethoxysilane (MTEOS) as the functional monomers, tetraethyl orthosilicate (TEOS) as the cross-linker and ethanol as the porogenic solvent in the surface of silica. The non-imprinted polymers layer-coated silica gel (NIP@SiO2) were prepared with the same procedure, but with the absence of template molecule. In addition, the optimum adsorption affinity occurred when the molar ratio of NDGA:APTS:MTEOS:TEOS was 1:6:2:80. The prepared MIP@SiO2 and NIP@SiO2 were analyzed by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform-infrared spectroscopy (FT-IR). Their affinity properties to NDGA were evaluated through dynamic adsorption, static adsorption, and selective recognition experiments, and the results showed the saturated adsorption capacity of MIP@SiO2 could reach to 5.90 mg g-1, which was two times more than that of NIP@SiO2. High performance liquid chromatography (HPLC) was used to evaluate the extraction of NDGA from the medicinal plant ephedra by the above prepared materials, and the results indicated that the MIP@SiO2 had potential application in separation of the natural active component NDGA from medicinal plants.

  17. Spatial correlation of proton irradiation-induced activity and dose in polymer gel phantoms for PET/CT delivery verification studies

    International Nuclear Information System (INIS)

    Purpose: This work demonstrates a novel application of BANG3-Pro2 polymer gel dosimeter as a dosimetric phantom able to accurately capture both dose and induced activity. Methods: BANG3-Pro2 dosimeters were irradiated with a clinical proton beam using an unmodulated beam and a spread-out Bragg peak (SOBP) modulation, the latter with a Lucite compensator to introduce a range offset in one quadrant of the circular field. The dosimeters were imaged in a nearby positron emission tomography/computed tomography (PET/CT) unit starting within 5 min of beam-off. Induced positron emission (PE) activity along the central axis of the beam was compared to analytical calculations. Dose distributions were read out using an optical CT scanner and were validated against ion chamber measurements and the treatment plan. The offset between the distal fall-off of dose and activity (50% level) was determined over the entire irradiated field. Lateral profiles of PE were correlated to measured dose for the unmodulated beam delivery. Results: Measured profiles of PE activity along the central beam axis were found to be within 10% of the predictions of analytical calculations. The depth-dose profiles agreed with the reference values (ion chamber or treatment plan) within 3%. The offset between the depth profiles of dose and activity for the unmodulated beam was 8.4 ± 1.4 mm. For the compensator-based SOBP delivery, the distribution of offsets throughout the field was found to be bimodal, with the mean of 8.9 ± 2.8 mm for the thinner region of the compensator and 4.3 ± 2.5 mm for the thicker region. For the pristine beam delivery, lateral profiles of dose and activity were found to exhibit fair spatial correlation throughout the beam range, with the mean 2D gamma index of 0.42 and 91% of the evaluated pixels passing the test. Conclusions: This work presents the first demonstration of simultaneous and accurate experimental measurement of three-dimensional distributions of dose and induced

  18. Efficacy of 1.23% APF gel applications on incipient carious lesions: a double-blind randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Maria Laura Menezes Bonow

    2013-06-01

    Full Text Available The aim of this double-blind randomized clinical trial was to evaluate the efficacy of 1.23% APF gel application on the arrest of active incipient carious lesions in children. Sixty 7- to 12-year-old children, with active incipient lesions were included in the study. Children were divided randomly into 2 groups: 1.23% APF gel and placebo gel applications. Each group received 8 weekly applications of treatment. The lesions were re-evaluated at the 4th and 8th appointments. Poisson regression analysis was used to estimate relative risks of the presence of active white spot lesions. Groups showed similar results (PR = 1.67; CI 95% 0.69–3.98. The persistence of at least 1 active lesion was associated with a higher number of lesions in the baseline (PR = 2.67; CI 95% 1.19–6.03, but not with sugar intake (PR = 1.06; CI 95% 0.56–2.86 and previous exposure to fluoride dentifrice (PR = 1.26; CI 95% 0.49–2.29. The trial demonstrates the equivalence of the treatments. The use of the APF gel showed no additional benefits in this sample of children exposed to fluoridated water and dentifrice. The professional dental plaque removal in both groups may also account for the resulting equivalence of the treatments.

  19. Feasibility study using MRI and two optical CT scanners for readout of polymer gel and PresageTM

    Science.gov (United States)

    Svensson, H.; Skyt, P. S.; Ceberg, S.; Doran, S.; Muren, L. P.; Balling, P.; Petersen, J. B. B.; Bäck, S. Å. J.

    2013-06-01

    The aim of this study was to compare the conventional combination of three-dimensional dosimeter (nPAG gel) and readout method (MRI) with other combinations of three-dimensional dosimeters (nPAG gel/PresageTM) and readout methods (optical CT scanners). In the first experiment, the dose readout of a gel irradiated with a four field-box technique was performed with both an Octopus IQ scanner and MRI. It was seen that the MRI readout agreed slightly better to the TPS. In another experiment, a gel and a PresageTM sample were irradiated with a VMAT field and read out using MRI and a fast laser scanner, respectively. A comparison between the TPS and the volumes revealed that the MRI/gel readout had closer resemblance to the TPS than the optical CT/PresageTM readout. There are clearly potential in the evaluated optical CT scanners, but more time has to be invested in the particular scanning scenario than was possible in this study.

  20. Effect of polyacrylonitrile on triethylene glycol diacetate-2-propenoic acid butyl ester gel polymer electrolytes with interpenetrating crosslinked network for flexible lithium ion batteries

    Science.gov (United States)

    Wang, Qiujun; Song, Wei-Li; Fan, Li-Zhen; Shi, Qiao

    2015-11-01

    A new flexible gel polymer electrolytes (GPE) with interpenetrating cross-linked network is fabricated by blending long-chain polyacrylonitrile (PAN) polymer matrix and short-chain triethylene glycol diacetate-2-propenoic acid butyl ester (TEGDA-BA) framework, with the purpose of enhancing the mechanical stability of the GPE frameworks via synergistic effects of the linear polymers and crosslinked monomers. The as fabricated frameworks enable the liquid electrolytes to be firmly entrapped in the polymeric matrices, which significantly improves the mechanical bendability and interface stability of the resultant GPE. The GPE with 5 wt% PAN exhibits high ionic conductivity up to 5.9 × 10-3 S cm-1 at 25 °C with a stable electrochemical window observed (>5.0 V vs. Li/Li+). The Li|GPE|LiFePO4 half cells demonstrate remarkably stable capacity retention and rate ability during cycling tests. As expected, the LiFePO4|GPE|Li4Ti5O12 full cells also exhibit discharge capacity of 125.2 mAh g-1 coupled with high columbic efficiency greater than 98% after 100 cycles. The excellent mechanical flexibility and charge/discharge performance suggest that the GPE holds great application potential in flexible LIBs.

  1. Arnica montana gel in osteoarthritis of the knee: an open, multicenter clinical trial.

    Science.gov (United States)

    Knuesel, Otto; Weber, Michel; Suter, Andy

    2002-01-01

    This open multicenter trial investigated the safety and efficacy of an Arnica montana fresh plant gel, applied twice daily, in 26 men and 53 women with mild to moderate osteoarthritis (OA) of the knee. After 3 and 6 weeks, significant decreases in median total scores on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were evident in the intention-to-treat and per-protocol populations (both P < .0001). Scores on the pain, stiffness, and function subscales also showed significant reductions at these timepoints. The overall local adverse-event rate of 7.6% included only one allergic reaction. Sixty-nine patients (87%) rated the tolerability of the gel as "good" or "fairly good," and 76% would use it again. Topical application of Arnica montana gel for 6 weeks was a safe, well-tolerated, and effective treatment of mild to moderate OA of the knee.

  2. Solid-state electric double layer capacitors fabricated with plastic crystal based flexible gel polymer electrolytes: Effective role of electrolyte anions

    Energy Technology Data Exchange (ETDEWEB)

    Suleman, Mohd; Kumar, Yogesh; Hashmi, S.A., E-mail: sahashmi@physics.du.ac.in

    2015-08-01

    Flexible gel polymer electrolyte (GPE) thick films incorporated with solutions of lithium trifluoromethanesulfonate (Li-triflate or LiTf) and lithium bis trifluoromethane-sulfonimide (LiTFSI) in a plastic crystal succinonitrile (SN), entrapped in poly(vinylidine fluoride-co-hexafluoropropylene) (PVdF-HFP) have been prepared and characterized. The films have been used as electrolytes in the electrical double layer capacitors (EDLCs). Coconut-shell derived activated carbon with high specific surface area (∼2100 m{sup 2} g{sup −1}) and mixed (micro- and meso-) porosity has been used as EDLC electrodes. The structural, thermal, and electrochemical characterization of the GPEs have been performed using scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), impedance measurements and cyclic voltammetry. The high ionic conductivity (∼10{sup −3} S cm{sup −1} at 25 °C), good electrochemical stability window (>4.0 V) and flexible nature of the free-standing films of GPEs show their competence in the fabrication of EDLCs. The EDLCs have been tested using electrochemical impedance spectroscopy, cyclic voltammetry, and charge–discharge studies. The EDLCs using LiTf based electrolyte have been found to give higher values of specific capacitance, specific energy, power density (240–280 F g{sup −1}, ∼39 Wh kg{sup −1} and ∼19 kW kg{sup −1}, respectively) than the EDLC cell with LiTFSI based gel electrolyte. EDLCs have been found to show stable performance for ∼10{sup 4} charge–discharge cycles. The comparative studies indicate the effective role of electrolyte anions on the capacitive performance of the solid-state EDLCs. - Graphical abstract: Display Omitted - Highlights: • Flexible EDLCs with succinonitrile based gel electrolyte membranes are reported. • Anionic size of salts in gel electrolytes plays important role on capacitive performance. • Li-triflate incorporated gel electrolyte shows better

  3. Solid-state electric double layer capacitors fabricated with plastic crystal based flexible gel polymer electrolytes: Effective role of electrolyte anions

    International Nuclear Information System (INIS)

    Flexible gel polymer electrolyte (GPE) thick films incorporated with solutions of lithium trifluoromethanesulfonate (Li-triflate or LiTf) and lithium bis trifluoromethane-sulfonimide (LiTFSI) in a plastic crystal succinonitrile (SN), entrapped in poly(vinylidine fluoride-co-hexafluoropropylene) (PVdF-HFP) have been prepared and characterized. The films have been used as electrolytes in the electrical double layer capacitors (EDLCs). Coconut-shell derived activated carbon with high specific surface area (∼2100 m2 g−1) and mixed (micro- and meso-) porosity has been used as EDLC electrodes. The structural, thermal, and electrochemical characterization of the GPEs have been performed using scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), impedance measurements and cyclic voltammetry. The high ionic conductivity (∼10−3 S cm−1 at 25 °C), good electrochemical stability window (>4.0 V) and flexible nature of the free-standing films of GPEs show their competence in the fabrication of EDLCs. The EDLCs have been tested using electrochemical impedance spectroscopy, cyclic voltammetry, and charge–discharge studies. The EDLCs using LiTf based electrolyte have been found to give higher values of specific capacitance, specific energy, power density (240–280 F g−1, ∼39 Wh kg−1 and ∼19 kW kg−1, respectively) than the EDLC cell with LiTFSI based gel electrolyte. EDLCs have been found to show stable performance for ∼104 charge–discharge cycles. The comparative studies indicate the effective role of electrolyte anions on the capacitive performance of the solid-state EDLCs. - Graphical abstract: Display Omitted - Highlights: • Flexible EDLCs with succinonitrile based gel electrolyte membranes are reported. • Anionic size of salts in gel electrolytes plays important role on capacitive performance. • Li-triflate incorporated gel electrolyte shows better performance over LiTFSI-based gel. • Highest

  4. Preoperative povidone-iodine vaginal gel in abdominal hysterectomy: a randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Beigi A

    2007-09-01

    Full Text Available Background: Infectious complications of hysterectomy remain common despite the use of antibiotic. The usual existing methods of preoperative antisepsis do not control the vaginal bacteria that are the primary cause of contamination at the surgical site. Our goal was to assess whether febrile morbidity after total abdominal hysterectomy is decreased by the addition of povidone-iodine gel at the vaginal apex after the routine vaginal preparation with povidone-iodine solution.Methods: We carried out a prospective randomized trial on women admitted for elective abdominal hysterectomy. Inclusion criteria included planned abdominal hysterectomy for benign or malignant gynecologic conditions. Exclusion criteria consisted of emergency surgery, current treatment for pelvic infection, and known povidone-iodine allergy. A total of 168 patients were randomized to either the control group or the intervention group, who received 20 cc povidone-iodine gel placed at the vaginal apex immediately before the operation. Both groups received the routine preoperative preparation of antimicrobial prophylaxis, abdominal and vaginal scrubbing with povidone-iodine solution prior to the operation. The primary outcome was post-operative febrile morbidity. Other outcomes included abdominal wound infection, vaginal cuff cellulitis or pelvic abscess. Data was analyzed using Fisher's exact test. p<0.05 was considered statistically significant.Results: The overall rate of febrile morbidity was 20.5%. Febrile morbidity occurred in ten of 80 (12.5% women receiving the povidone-iodine gel preparation and 24 of 86 (27.9% women not receiving the gel (p<0.05. The rate of abdominal wound infection was 18.6% (16 in the control group, and 5% (4 in the gel group (p<0.05. Vaginal cuff cellulitis was seen in three patients from the control group versus one woman from the gel group (p>0.05. Pelvic abscess was diagnosed in one patient from the control group and in no patients from the

  5. Effects of Standardised Fermented Papaya Gel on Clinical Symptoms, Inflammatory Cytokines, and Nitric Oxide Metabolites in Patients with Chronic Periodontitis: An Open Randomised Clinical Study

    OpenAIRE

    Kharaeva, Zaira F.; Zhanimova, Lyana R.; Magomet Sh. Mustafaev; Chiara De Luca; Wolfgang Mayer; Jeffrey Chung Sheun Thai; Rebecca Tiew Siok Tuan; Korkina, Liudmila G.

    2016-01-01

    The clinical efficacy of topical administration of standardised fermented papaya gel (SFPG), known to have antioxidant and anti-inflammatory properties, versus conventional therapy was evaluated in a group of 84 patients with moderate-to-severe periodontitis, randomly assigned to control group (n = 45) undergoing traditional pharmacologic/surgical protocols or to experimental group (n = 39), additionally treated with intragingival pocket SFPG (7 g) applications (15 min daily for 10 days). Pat...

  6. Protein composition of wheat gluten polymer fractions determined by quantitative two-dimensional gel electrophoresis and tandem mass spectrometry

    Science.gov (United States)

    Flour proteins from the US bread wheat Butte 86 were extracted in 0.5% SDS using a two-step procedure with and without sonication and further separated by size exclusion chromatography into monomeric and polymeric fractions. Proteins in each fraction were analyzed by quantitative two-dimensional gel...

  7. SU-E-CAMPUS-T-05: Validation of High-Resolution 3D Patient QA for Proton Pencil Beam Scanning and IMPT by Polymer Gel Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Cardin, A; Avery, S; Ding, X; Kassaee, A; Lin, L [University of Pennsylvania, Philadelphia, PA (United States); Maryanski, M [MGS Research, Inc., Madison, CT (United States)

    2014-06-15

    Purpose: Validation of high-resolution 3D patient QA for proton pencil beam scanning and IMPT by polymer gel dosimetry. Methods: Four BANG3Pro polymer gel dosimeters (manufactured by MGS Research Inc, Madison, CT) were used for patient QA at the Robert's Proton Therapy Center (RPTC, Philadelphia, PA). All dosimeters were sealed in identical thin-wall Pyrex glass spheres. Each dosimeter contained a set of markers for 3D registration purposes. The dosimeters were mounted in a consistent and reproducible manner using a custom build holder. Two proton pencil beam scanning plans were designed using Varian Eclipse™ treatment planning system: 1) A two-field intensity modulated proton therapy (IMPT) plan and 2) one single field uniform dose (SFUD) plan. The IMPT fields were evaluated as a composite plan and individual fields, the SFUD plan was delivered as a single field plan.Laser CT scanning was performed using the manufacturer's OCTOPUS-IQ axial transmission laser CT scanner using a 1 mm slice thickness. 3D registration, analysis, and OD/cm to absorbed dose calibrations were perfomed using DICOM RT-Dose and CT files, and software developed by the manufacturer. 3D delta index, a metric equivalent to the gamma tool, was used for dose comparison. Results: Very good agreement with single IMPT fields and with SFUD was obtained. Composite IMPT fields had a less satisfactory agreement. The single fields had 3D delta index passing rates (3% dose difference, 3 mm DTA) of 98.98% and 94.91%. The composite 3D delta index passing rate was 80.80%. The SFUD passing rate was 93.77%. Required shifts of the dose distributions were less than 4 mm. Conclusion: A formulation of the BANG3Pro polymer gel dosimeter, suitable for 3D QA of proton patient plans is established and validated. Likewise, the mailed QA analysis service provided by the manufacturer is a practical option when required resources are unavailable. We fully disclose that the subject of this research regards a

  8. Improved Mobility Control for Carbon Dioxide (CO{sub 2}) Enhanced Oil Recovery Using Silica-Polymer-Initiator (SPI) Gels

    Energy Technology Data Exchange (ETDEWEB)

    Oglesby, Kenneth

    2014-01-31

    SPI gels are multi-component silicate based gels for improving (areal and vertical) conformance in oilfield enhanced recovery operations, including water-floods and carbon dioxide (CO{sub 2}) floods, as well as other applications. SPI mixtures are like-water when pumped, but form light up to very thick, paste-like gels in contact with CO{sub 2}. When formed they are 3 to 10 times stronger than any gelled polyacrylamide gel now available, however, they are not as strong as cement or epoxy, allowing them to be washed / jetted out of the wellbore without drilling. This DOE funded project allowed 8 SPI field treatments to be performed in 6 wells (5 injection wells and 1 production well) in 2 different fields with different operators, in 2 different basins (Gulf Coast and Permian) and in 2 different rock types (sandstone and dolomite). Field A was in a central Mississippi sandstone that injected CO{sub 2} as an immiscible process. Field B was in the west Texas San Andres dolomite formation with a mature water-alternating-gas miscible CO{sub 2} flood. Field A treatments are now over 1 year old while Field B treatments have only 4 months data available under variable WAG conditions. Both fields had other operational events and well work occurring before/ during / after the treatments making definitive evaluation difficult. Laboratory static beaker and dynamic sand pack tests were performed with Ottawa sand and both fields’ core material, brines and crude oils to improve SPI chemistry, optimize SPI formulations, ensure SPI mix compatibility with field rocks and fluids, optimize SPI treatment field treatment volumes and methods, and ensure that strong gels set in the reservoir. Field quality control procedures were designed and utilized. Pre-treatment well (surface) injectivities ranged from 0.39 to 7.9 MMCF/psi. The SPI treatment volumes ranged from 20.7 cubic meters (m{sup 3}, 5460 gallons/ 130 bbls) to 691 m{sup 3} (182,658 gallons/ 4349 bbls). Various size and types

  9. DMA and Conductivity Studies in PVA:NH4SCN:DMSO:MWNT Nanocomposite Polymer Dried Gel Electrolytes

    Directory of Open Access Journals (Sweden)

    S. L. Agrawal

    2015-01-01

    Full Text Available This paper deals with findings on dynamic mechanical analysis (DMA and ion-conduction behavior of MWNTs (multiwall carbon nanotubes doped PVA:NH4SCN:DMSO dried gel electrolyte system prepared for four filler concentrations (2, 4, 6 & 8 wt% by solution cast technique. XRD measurements reveal enhancement in amorphous behavior of composite gel electrolyte upon incorporation of filler particles. Better mechanical stability is noticed in the composite system upon dispersal of MWNT along with presence of dynamic Tg during DMA measurements. Enhancement in ionic conductivity has been noticed with an optimum value of 4.5 × 10−3 Scm−1 for 6 wt% MWNTs filled composite electrolyte. Composite system exhibits combination of Arrhenius and Vogel-Tammam-Fulcher (VTF behavior in temperature dependent conductivity study. The a.c. conductivity response seems to follow universal power law.

  10. An application of optical coherence tomography and a smart polymer gel to construct an enzyme-free sugar sensor

    Science.gov (United States)

    Ouiganon, Sirirat; Thammakhet, Chongdee; Thavarungkul, Panote; Kanatharana, Proespichaya; Buranachai, Chittanon

    2016-06-01

    This work reports a novel enzyme-free sugar sensor development based on optical coherence tomography (OCT) and a 3-acrylamidophenylboronic acid-acrylamide copolymer gel that swells when it binds sugar molecules. Utilizing OCT to measure the gel swelling in the presence of glucose and fructose, selected as model targets, the sensor provided a linear range of 2.5-20.0 mM for glucose and 0.01-0.20 mM for fructose detections with a good sensitivity for both sugars under optimal conditions. With some further improvements, the sensor could be used in harsh conditions that are not suitable for enzyme-based sugar sensors and for highly visible light-absorbing solutions.

  11. Randomized, controlled clinical study to evaluate efficacy of novel indigenously designed controlled release flurbiprofen gel system for management of periodontal diseases

    Directory of Open Access Journals (Sweden)

    Neeraj C Deshpande

    2013-01-01

    Full Text Available Background: This randomized, controlled clinical study was planned to evaluate the use of anti-inflammatory drug flurbiprofen in the form of locally delivered controlled release gel in the treatment of periodontal disease. Materials and Methods: The flurbiprofen gel was indigenously prepared in the concentration of 0.3%. The 30 patients with localized periodontal pockets measuring ≥5 mm were randomly divided into three groups. The groups received flurbiprofen gel, flurbiprofen gel after prophylaxis, and placebo gel after oral prophylaxis, respectively. The clinical parameters for plaque and gingival inflammation were evaluated at baseline, 7 th day, and 14 th day. Results: The results of the study suggested the statistically significant ( P < 0.05 improvement in the gingival status of the patients with the use of flurbiprofen gel as an adjunct to scaling and root planing as compared to oral prophylaxis or gel alone. Conclusion: The data demonstrated that the additional use of local drug delivery of flurbiprofen through gel media enhances the positive effects of scaling and root planing and helps in faster resolution of the inflammation.

  12. Randomized, controlled clinical study to evaluate efficacy of novel indigenously designed controlled release flurbiprofen gel system for management of periodontal diseases

    Science.gov (United States)

    Deshpande, Neeraj C.; Bhat, K. M.; Bhat, G. S.; Deshpande, Anshula N.

    2013-01-01

    Background: This randomized, controlled clinical study was planned to evaluate the use of anti-inflammatory drug flurbiprofen in the form of locally delivered controlled release gel in the treatment of periodontal disease. Materials and Methods: The flurbiprofen gel was indigenously prepared in the concentration of 0.3%. The 30 patients with localized periodontal pockets measuring ≥5 mm were randomly divided into three groups. The groups received flurbiprofen gel, flurbiprofen gel after prophylaxis, and placebo gel after oral prophylaxis, respectively. The clinical parameters for plaque and gingival inflammation were evaluated at baseline, 7th day, and 14th day. Results: The results of the study suggested the statistically significant (P < 0.05) improvement in the gingival status of the patients with the use of flurbiprofen gel as an adjunct to scaling and root planing as compared to oral prophylaxis or gel alone. Conclusion: The data demonstrated that the additional use of local drug delivery of flurbiprofen through gel media enhances the positive effects of scaling and root planing and helps in faster resolution of the inflammation. PMID:23853449

  13. Comparison between Monte Carlo simulation and measurement with a 3D polymer gel dosimeter for dose distributions in biological samples

    International Nuclear Information System (INIS)

    In this research, we used a 135 MeV/nucleon carbon-ion beam to irradiate a biological sample composed of fresh chicken meat and bones, which was placed in front of a PAGAT gel dosimeter, and compared the measured and simulated transverse-relaxation-rate (R2) distributions in the gel dosimeter. We experimentally measured the three-dimensional R2 distribution, which records the dose induced by particles penetrating the sample, by using magnetic resonance imaging. The obtained R2 distribution reflected the heterogeneity of the biological sample. We also conducted Monte Carlo simulations using the PHITS code by reconstructing the elemental composition of the biological sample from its computed tomography images while taking into account the dependence of the gel response on the linear energy transfer. The simulation reproduced the experimental distal edge structure of the R2 distribution with an accuracy under about 2 mm, which is approximately the same as the voxel size currently used in treatment planning. (paper)

  14. Comparison between Monte Carlo simulation and measurement with a 3D polymer gel dosimeter for dose distributions in biological samples

    Science.gov (United States)

    Furuta, T.; Maeyama, T.; Ishikawa, K. L.; Fukunishi, N.; Fukasaku, K.; Takagi, S.; Noda, S.; Himeno, R.; Hayashi, S.

    2015-08-01

    In this research, we used a 135 MeV/nucleon carbon-ion beam to irradiate a biological sample composed of fresh chicken meat and bones, which was placed in front of a PAGAT gel dosimeter, and compared the measured and simulated transverse-relaxation-rate (R2) distributions in the gel dosimeter. We experimentally measured the three-dimensional R2 distribution, which records the dose induced by particles penetrating the sample, by using magnetic resonance imaging. The obtained R2 distribution reflected the heterogeneity of the biological sample. We also conducted Monte Carlo simulations using the PHITS code by reconstructing the elemental composition of the biological sample from its computed tomography images while taking into account the dependence of the gel response on the linear energy transfer. The simulation reproduced the experimental distal edge structure of the R2 distribution with an accuracy under about 2 mm, which is approximately the same as the voxel size currently used in treatment planning.

  15. Three-dimensional verification of intracranial target point deviation using MRI-Based polymer-gel dosimetry for conventional and fractionated stereotactic radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Nam; Suh, Tae Suk [The Catholic University of Korea College of Medicine, Seoul (Korea, Republic of); Lee, Dong Joon [Ilsanpaik Hospital, College of Medicine, Inje University, Goyang (Korea, Republic of)

    2011-09-15

    Conventional (SRS) and fractionated (FSRS) stereotactic radiosurgery necessarily require stringent overall target point accuracy and precision. We determine three-dimensional intracranial target point deviations (TPDs) in a whole treatment procedure using magnetic resonance image (MRI)-based polymer-gel dosimetry, and suggest a technique for overall system tests. TPDs were measured using a custom-made head phantom and gel dosimetry. We calculated TPDs using a treatment planning system. Then, we compared TPDs using mid bi-plane and three-dimensional volume methods with spherical and elliptical targets to determine their inherent analysis errors; finally, we analyzed regional TPDs using the latter method. Average and maximum additive errors for ellipses were 0.62 and 0.69 mm, respectively. Total displacements were 0.92 {+-} 0.25 and 0.77 {+-} 0.15 mm for virtual SRS and FSRS, respectively. Average TPDtotal at peripheral regions was greater than that at central regions for both. Overall system accuracy was similar to that reported previously. Our technique could be used as an overall system accuracy test that considers the real radiation field shape.

  16. Directed shift of vaginal flora after topical application of sucrose gel in a phase Ⅲ clinical trial: a novel treatment for bacterial vaginosis

    Institute of Scientific and Technical Information of China (English)

    ZENG Zhong-ming; PANG Yi-cun; LIU Shu-wen; JIANG Shi-bo; LIAO Qin-pin; YAO Chen; GENG Li; FENG Li-hua; SHI Hui-rong; XIN Xiao-yan; LI Ping; WANG Hui-lan

    2010-01-01

    Background Bacterial vaginosis (BV) is one of the most common infectious diseases among sexually active women and is associated with the increased acquisition of a variety of sexually transmitted diseases.This study aimed to compare the efficacy of a non-antibiotic sucrose gel against an antibiotic metronidazole gel for the treatment of BV.Methods A randomized, double-blinded, multi-center, parallel-group, placebo-controlled phase Ⅲ clinical trial was conducted at eight hospitals in China.A total of 560 subjects with clinically diagnosed BV were randomly assigned into three groups for vaginally receiving sucrose, metronidazole, and placebo gels, respectively, twice daily for five consecutive days.The efficacy of therapeutic cure, defined as an achievement of both microbiologic cure (a Nugent score of 3 or less) and clinical cure (a resolution of the clinical findings from the baseline visit), was evaluated at the 1st and 2nd test-of-cure (TOC) visits at 7-10 and 21-35 days after the start of treatment, respectively.Results Therapeutic cure rates for sucrose, metronidazole, and placebo gel groups were 83.13%, 71.30% and 0.92%,at the 1st TOC, and 61.04%, 66.67% and 7.34%, at the 2nd TOC, respectively.While there was no significant difference between the sucrose and metronidazole gel groups at the 2nd TOC (P=0.305), and sucrose gel was more effective than metronidazole gel at the 1st TOC (P=0.009).Conclusion These findings suggest that sucrose gel restores normal vaginal flora more rapidly than metronidazole gel and can be used as a novel treatment for BV.

  17. Postcoital bioavailability and antiviral activity of 0.5% PRO 2000 gel: implications for future microbicide clinical trials.

    Directory of Open Access Journals (Sweden)

    Marla J Keller

    Full Text Available BACKGROUND: The pharmacokinetics and pharmacodynamics of vaginal microbicides are typically assessed among sexually abstinent women. However, the physical act of sex may modulate gel distribution, and preclinical studies demonstrate seminal plasma interferes with the antiviral activity of several microbicides. This study compared the biological activity and concentration of PRO 2000 in cervicovaginal lavage (CVL collected in the absence or following coitus. METHODS: CVL samples were collected from ten heterosexual couples at baseline, after sex, after a single dose of 0.5% PRO 2000 gel and sex, and after gel application without sex. The impact of CVL on HIV-1 infection of TZM-bl cells and HSV-2 infection of CaSki cells was monitored by luciferase and plaque assay, respectively. PRO 2000 concentrations were measured by fluorescence. RESULTS: CVL collected after PRO 2000 application significantly inhibited HIV-1 and HSV-2 (p = 0.01. However, the antiviral activity was reduced following sex and no significant protective effect was observed in postcoital CVL obtained in the presence compared to the absence of PRO 2000 for HIV (p = 0.45 or HSV-2 (p = 0.56. Less PRO 2000 was recovered in postcoital CVL, which, in conjunction with interference by seminal plasma, may have contributed to lower antiviral activity. CONCLUSIONS: Postcoital responses to PRO 2000 differ from precoital measures and the results obtained may provide insights into the clinical trial findings in which there was no significant protection against HIV-1 or HSV-2. Postcoital studies should be incorporated into clinical studies before embarking on large-scale efficacy trials.

  18. Effect of Thiolated Polymers to Textural and Mucoadhesive Properties of Vaginal Gel Formulations Prepared with Polycarbophil and Chitosan

    OpenAIRE

    Cevher, Erdal; Sensoy, Demet; Taha, Mohamed A. M.; Araman, Ahmet

    2008-01-01

    The aim of this study was to design and evaluate of mucoadhesive gel formulations for the vaginal application of clomiphene citrate (CLM) for local treatment of human papilloma virus (HPV) infections. Chitosan (CHI) and polycarbophil (PC) were covalently modified using the thioglycolic acid and L-cysteine, respectively. The formation of thiol conjugates of chitosan (CHI-TG) and polycarbophil (PC-CYS) were confirmed by FT-IR analysis and PC-CYS and CHI-TG were found to have 148.42 ± 4.16 and 4...

  19. Relationship between clinical manifestations and pulsed-field gel profiles of Streptococcus canis isolates from dogs and cats.

    Science.gov (United States)

    Kruger, E Freya; Byrne, Barbara A; Pesavento, Patricia; Hurley, Kate F; Lindsay, Leanne L; Sykes, Jane E

    2010-11-20

    Little is known regarding the degree of genotypic relatedness between Streptococcus canis isolates from dogs and cats. The purpose of this study was to determine whether correlations existed between the genotypes of canine and feline S. canis isolates as determined using pulsed-field gel electrophoresis (PFGE) and different clinical manifestations of disease. Eighty-two isolates of S. canis were examined that had been collected from dogs and cats presenting to the University of California, Davis Veterinary Medical Teaching Hospital (VMTH) between 1998 and 2005. Associated clinical manifestations included sepsis, otitis, pyometra, skin infections, necrotizing fasciitis, respiratory disease, and urinary tract infections. In addition, 9 feline isolates from a southern California shelter that experienced an outbreak of S. canis infection manifesting as necrotizing fasciitis and death were examined. Bacterial isolates were characterized by PFGE analysis using the restriction enzyme SmaI. The relationships between banding patterns were analyzed using gel analysis software combined with visual interpretation. The feline shelter isolates of S. canis were 99% similar in bacterial PFGE profile. The remainder of samples had less than 80% similarity in PFGE banding patterns. The relatedness of the PFGE profile in the feline shelter isolates suggested a clonal origin. In the isolates from the VMTH population, there was no relationship between specific disease manifestations and PFGE profile. PFGE typing does not appear to be useful for identifying isolates associated with specific disease presentations; however may be more useful to identify outbreaks of S. canis infections or to detect clonal populations in outbreaks. PMID:20605376

  20. CONFORMANCE IMPROVEMENT USING GELS

    Energy Technology Data Exchange (ETDEWEB)

    Randall S. Seright

    2003-09-01

    flow capacity of fractures (with widths from 1 to 4 mm) during brine and oil flow after placement. Regardless of gel age before placement, very little gel washed out from the fractures during brine or oil flow. However, increased brine or oil flow rate and cyclic injection of oil and water significantly decreased the level of permeability reduction. A particular need exists for gels that can plug large apertures (e.g., wide fractures and vugs). Improved mechanical strength and stability were demonstrated (in 1- to 4-mm-wide fractures) for a gel that contained a combination of high- and low-molecular weight polymers. This gel reduced the flow capacity of 2- and 4-mm-wide fractures by 260,000. In a 1-mm-wide fracture, it withstood 26 psi/ft without allowing any brine flow through the fracture. Cr(III)-acetate-HPAM gels exhibited disproportionate permeability reduction in fractures. The effect was most pronounced when the gel was placed as gelant or partially formed gels. The effect occurred to a modest extent with concentrated gels and with gels that were ''fully formed'' when placed. The effect was not evident in tubes. We explored swelling polymers for plugging fractures. Polymer suspensions were quickly prepared and injected. In concept, the partially dissolved polymer would lodge and swell to plug the fracture. For three types of swelling polymers, behavior was promising. However, additional development is needed before their performance will be superior to that of conventional gels.

  1. A comparative study of the clinical efficiency of chemomechanical caries removal using Carisolv® and Papacarie® - A papain gel

    OpenAIRE

    Kumar, J.; Nayak, M.; K L Prasad; Gupta, N.

    2012-01-01

    Objectives: The purpose of this study was to compare the clinical efficiency of chemomechanical caries removal using Carisolv® and Papacarie® - a papain gel. Materials and Methods: The Carisolv® system for caries removal, consisting of a solvent gel and a specially designed hand instrument, was compared to Papacarie - a papain gel. The outcome variables were: time taken for complete caries removal and volume of carious tissue excavated. Forty patients in the age-group of 20-40 years, havi...

  2. Fabricating porous materials using interpenetrating inorganic-organic composite gels

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Dong-Kyun; Volosin, Alex

    2016-06-14

    Porous materials are fabricated using interpenetrating inorganic-organic composite gels. A mixture or precursor solution including an inorganic gel precursor, an organic polymer gel precursor, and a solvent is treated to form an inorganic wet gel including the organic polymer gel precursor and the solvent. The inorganic wet gel is then treated to form a composite wet gel including an organic polymer network in the body of the inorganic wet gel, producing an interpenetrating inorganic-organic composite gel. The composite wet gel is dried to form a composite material including the organic polymer network and an inorganic network component. The composite material can be treated further to form a porous composite material, a porous polymer or polymer composite, a porous metal oxide, and other porous materials.

  3. THE EFFICACY AND SAFETY OF CARMOLIS GEL IN THE COMBINATION THERAPY OF KNEE OSTEOARTHRITIS: RESULTS OF A MULTICENTER CLINICAL TRIAL

    Directory of Open Access Journals (Sweden)

    I. N. Denisov

    2015-01-01

    Full Text Available Osteoarthritis (OA is one of the most common rheumatic diseases. Knee OA is particularly frequently encountered among all forms of OA, the prevalence of knee OA being about 25% in the general population. Despite multiple guidelines for the management of knee OA, which have been prepared by the European League Against Rheumatism (EULAR, the American College of Rheumatology (ACR, and the Osteoarthritis Research Society International (OARSI, many problems of its treatment policy remain to be solved. The same holds true for not only the symptomatic and disease-modifying effects of chondroprotectors, but also topical therapy options.Objective: to evaluate the clinical efficacy and safety of Carmolis gel in patients with knee OA.Subjects and methods.The trial included 280 patients with knee OA (a study group consisted of 190 patents; a control group comprised 90 patients. The mean age was 58.3±9.3 years in the study group and 59±10.5 years in the control group. The disease duration was 10.3±5.5 and 10.1±4.1 years, respectively. Carmolis gel was applied to the region of the most painful knee joint up to 4–5 times daily, followed by massage of this skin area. The treatment cycle lasted for 2 weeks. No therapy was performed in the control patients. The clinical efficacy was determined by the changes in joint pains at rest or on movement and palpation, according to a visual analogue scale (VAS, WOMAC questionnaire, the synovitis intensity (assessed by ultrasonography, patient and physician global assessments of disease activity (Likert scale, and the possibility of reducing the daily dosage of nonsteroidal anti-inflammatory drugs (NSAIDs. The onset the therapeutic effect of the gel and the duration of its action were recorded.Results and discussion. The topical application of Carmolis gel caused a statistically significant reduction in joint pain at rest and on movement from 57.7±6.8 to 12±1.8 mm (р < 0.01 and from 52±5.3 to 17±2.7 mm

  4. Treatment of pain in fibromyalgia patients with testosterone gel: Pharmacokinetics and clinical response.

    Science.gov (United States)

    White, Hillary D; Brown, Lin A J; Gyurik, Robert J; Manganiello, Paul D; Robinson, Thomas D; Hallock, Linda S; Lewis, Lionel D; Yeo, Kiang-Teck J

    2015-08-01

    To test our hypothesis that testosterone deficiency plays an important role in chronic pain, a Phase I/II pilot study was initiated with 12 fibromyalgia patients to verify that a daily dose for 28days with transdermal testosterone gel would 1) significantly and safely increase mean serum testosterone concentrations from low baseline levels to mid/high-normal levels, and 2) effectively treat the pain and fatigue symptoms of fibromyalgia. Pharmacokinetic data confirmed that serum free testosterone concentrations were raised significantly above baseline levels, by assessment of maximum hormone concentration (Cmax) and area under the curve (AUC) parameters: free testosterone Cmax was significantly raised from a mean of 2.64pg/mL to 3.91pg/mL (pincreased libido during study treatment. These results are consistent with the hypothesized ability of testosterone to relieve the symptoms of fibromyalgia. Symptoms not tightly related to fibromyalgia were not improved. PMID:26004317

  5. Randomized controlled clinical trial of long-term chemo-mechanical caries removal using PapacarieTM gel

    Directory of Open Access Journals (Sweden)

    Lara Jansiski MOTTA

    2014-07-01

    Full Text Available Objectives: Compare the effectiveness of PapacarieTM gel for the chemo-mechanical removal of carious lesions on primary teeth to conventional caries removal with a low-speed bur with regard to execution time, clinical aspects and radiographic findings. Material and Methods: A randomized controlled clinical trial with a split-mouth design was carried out. The sample was composed of 20 children aged four to seven years, in whom 40 deciduous teeth were randomly divided into two groups: chemo-mechanical caries removal with PapacarieTM and removal of carious dentin with a low-speed bur. Each child underwent both procedures and served as his/her own control. Restorations were performed with glass ionomer cement. The time required to perform the procedure was also analyzed. The patients underwent longitudinal clinical and radiographic follow-up of the restorations. Results: No statistically significant difference between groups was found regarding the time required to perform the procedures and the radiographic follow up. Statistically significant differences between groups were found in the clinical evaluation at 6 and 18 months after treatment. Conclusion: PapacarieTM is as effective as the traditional method for the removal of carious dentin on deciduous teeth, but offers the advantages of the preservation of sound dental tissue as well as the avoidance of sharp rotary instruments and local anesthesia.

  6. Clinical efficacy of subgingivally delivered 0.5% controlled release azithromycin gel in the management of chronic periodontitis

    Directory of Open Access Journals (Sweden)

    Prashant Tyagi

    2011-01-01

    Full Text Available Background: Recent developments suggest that the local delivery of antimicrobials into periodontal pockets can improve periodontal health. Azithromycin (AZM has a wide antimicrobial spectrum of action toward anaerobic bacteria as well as Gram-negative bacilli. It is effective against periodontal pathogens such as Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Therefore, this study was undertaken to investigate the clinical effectiveness of AZM at 0.5% concentration in an indigenously prepared bioabsorbable controlled release gel as an adjunct to non-surgical mechanical therapy in the treatment of chronic periodontitis. Materials and Methods: Thirty sites in patients with chronic periodontitis and probing depth (PD 4-6 mm were categorized randomly into two treatment groups: Scaling and root planing (SRP plus 0.5% AZM gel (group 1 and SRP only (group 2. Clinical evaluation was undertaken using the Gingival Index (GI of Loe and Silness and plaque was assessed using the Turesky et al. modification of Quigley Hein Index at baseline and 21 days. Pocket PD and clinical attachment level (CAL were also measured. Statistical Analysis: Results were expressed as mean ± standard deviation and percentages and the data were analyzed using Statistical Package for Social Sciences (SPSS version 16.0, SPSS, Chicago, IL software. Result: Both therapies resulted in significant improvements. Mean reduction in GI from baseline to 21 days was 1.20 ± 0.41 and 0.73 ± 0.45 in group 1 and group 2, respectively. Plaque Index also improved through the study period in both groups, i.e., 0.86 ± 0.51 in group 1 and 1.6 ± 0.97 in group 2. Mean PD reduced significantly with SRP plus AZM gel application in group 1, i.e., 2.1 ± 0.91 mm as compared to 1.0 ± 1.06 mm achieved with SRP alone. A significant gain in mean CAL gain was observed in the test group (1.8 ± 0.63 mm as compared to control group (1.0 ± 1.06 mm. Conclusion: Although both treatment

  7. The Effect of Honey Gel on Abdominal Wound Healing in Cesarean Section: A Triple Blind Randomized Clinical Trial

    Directory of Open Access Journals (Sweden)

    Maryam Nikpour

    2014-07-01

    Full Text Available Objective: To assess whether honey can accelerate the wound healing in women undergoing cesarean section. Methods: This was a triple blinded randomized prospective clinical trial. Women with cesarean section were randomly designated as drug (37 cases and placebo (38 cases groups. The drug group received local honey gel 25% while the placebo group received similar free-honey gel on abdominal cesarean incision twice a day for 14 days. REEDA scale (Redness, Edema, Ecchymosis, Discharge and Approximation of wound edges was used to assess wound healing. Results: The mean REEDA was 2.27 ± 2.46 and 3.91 ± 2.74 (p=0.008 on the 7th day and 0.47 ± 0.84 and 1.59± 1.95 (p=0.002 on the 14th day for the drug and placebo groups, respectively. Redness, edema and hematoma in the drug group were significantly lower on the 7th and 14th days. Conclusion: Honey was effective in healing the cesarean section incision. Using topical honey is suggested as a natural product with rare side effects in order to reduce the complications of cesarean wounds.

  8. Evaluation of the effect of hand hygiene reminder signs on the use of antimicrobial hand gel in a clinical skills center.

    Science.gov (United States)

    Wearn, Andy; Bhoopatkar, Harsh; Nakatsuji, Miriam

    2015-01-01

    Hand hygiene is a critical element of patient care, which needs to be learned and reinforced to become an autonomous behavior. Previous studies have explored aspects of hand hygiene behavior in the clinical workplace, but not in controlled learning environments with health professional students. Development of good hand hygiene behavior requires a multi-faceted approach, including education, reinforcement, feedback and audit. Our study aimed to identify the effect of unannounced hand hygiene reminder signs on the use of antimicrobial hand gel in a clinical skills center. Year 2 MBChB students received practical learning regarding hand hygiene in their clinical skills sessions. Baseline hand gel use was measured using before and after weighing of the bottles. An A5 sign was created to remind the students to hand cleanse and was used as an unannounced intervention. In semester 2 (2012), the student groups were randomly allocated as intervention (signs) or control (no signs). Hand gel use at all sessions was measured. Data were compared between groups and over time. In total, 237 students attended the skills sessions twice during the study. Hand gel use was not significantly different between the two study arms. Overall use was low, typically 1-2 hand gel pumps per student per session. In addition, hand gel use fell over time. A visual reminder to cleanse hands did not appear to have any effect on behavior. These findings may have implications for their value in a clinical setting. Low overall use of hand gel may be context-dependent. Students are in a simulated environment and examine 'healthy' peers or actors. There may have been inconsistent tutor role-modeling or problems with the educational approach to the skill. Analysis at the level of the group, and not the individual, may have also limited our study.

  9. Efficiency enhancement in dye sensitized solar cells using gel polymer electrolytes based on a tetrahexylammonium iodide and MgI2 binary iodide system.

    Science.gov (United States)

    Bandara, T M W J; Dissanayake, M A K L; Jayasundara, W J M J S R; Albinsson, I; Mellander, B-E

    2012-06-28

    Quasi-solid-state dye-sensitized solar cells have drawn the attention of scientists and technologists as a potential candidate to supplement future energy needs. The conduction of iodide ions in quasi-solid-state polymer electrolytes and the performance of dye sensitized solar cells containing such electrolytes can be enhanced by incorporating iodides having appropriate cations. Gel-type electrolytes, based on PAN host polymers and mixture of salts tetrahexylammonium iodide (Hex4N(+)I(-)) and MgI2, were prepared by incorporating ethylene carbonate and propylene carbonate as plasticizers. The salt composition in the binary mixture was varied in order to optimize the performance of solar cells. The electrolyte containing 120% Hex4N(+)I(-) with respect to weight of PAN and without MgI2 showed the highest conductivity out of the compositions studied, 2.5 × 10(-3) S cm(-1) at 25 °C, and a glass transition at -102.4 °C. However, the electrolyte containing 100% Hex4N(+)I(-) and 20% MgI2 showed the best solar cell performance highlighting the influence of the cation on the performance of the cell. The predominantly ionic behaviour of the electrolytes was established from the dc polarization data and all the electrolytes exhibit iodide ion transport. Seven different solar cells were fabricated employing different electrolyte compositions. The best cell using the electrolyte with 100% Hex4N(+)I(-) and 20% MgI2 with respect to PAN weight showed 3.5% energy conversion efficiency and 8.6 mA cm(-2) short circuit current density.

  10. Current-voltage characterization of Au contact on sol-gel ZnO films with and without conducting polymer

    International Nuclear Information System (INIS)

    This study investigates the current density-voltage (J-V) characteristics of Au/n-type ZnO and Au/polyaniline (PANI)/n-type ZnO devices. ZnO films were prepared by the sol-gel method. For Au/n-type ZnO devices, native defects and impurities resident within the ZnO depletion region contribute to barrier thinning of, carrier hopping across, and tunneling through the Schottky barrier. This leads to the formation of nonalloyed ohmic contacts. However, rectifying junctions were formed on n-type ZnO by employing the simple technique of spin-coating PANI to act as the electron-blocking layer. Our present results suggest that the ZnO depletion region at the PANI/n-type ZnO interface is not the origin of the rectifying behavior of Au/PANI/n-type ZnO contact. In addition, the presence of the built-in potential of Au/PANI/n-type ZnO devices could result in the shift of the J-V curve toward negative voltage. Excellent agreement between simulated and measured data was obtained when the built-in potential was taken into account in the J-V relationship.

  11. Porous bodies of hydroxyapatite produced by a combination of the gel-casting and polymer sponge methods.

    Science.gov (United States)

    González Ocampo, Jazmín I; Escobar Sierra, Diana M; Ossa Orozco, Claudia P

    2016-03-01

    A combination of gel-casting and polymeric foam infiltration methods is used in this study to prepare porous bodies of hydroxyapatite (HA), to provide a better control over the microstructures of samples. These scaffolds were prepared by impregnating a body of porous polyurethane foam with slurry containing HA powder, and using a percentage of solids between 40% and 50% w/v, and three different types of monomers to provide a better performance. X-Ray Diffraction (XRD), and Fourier Transformed Infrared (FTIR) and Scanning Electron Microscopy (SEM) were employed to evaluate both the powder hydroxyapatite and the scaffolds obtained. In addition, porosity and interconnectivity measurements were taken in accordance with the international norm. Bioactivity was checked using immersion tests in Simulated Body Fluids (SBF). After the sintering process of the porous bodies, the XRD results showed peaks characteristic of a pure and crystalline HA (JCPDS 9-432) as a single phase. SEM images indicate open and interconnected pores inside the material, with pore sizes between 50 and 600 μm. Also, SEM images demonstrate the relatively good bioactivity of the HA scaffolds after immersion in SBF. All results for the porous HA bodies suggest that these materials have great potential for use in tissue engineering. PMID:26966570

  12. Practical Guidance on How to Handle Levodopa/Carbidopa Intestinal Gel Therapy of Advanced PD in a Movement Disorder Clinic

    DEFF Research Database (Denmark)

    Pedersen, Stephen Wørlich; Clausen, Jesper Bøje; Gregerslund, Mie Manon

    2012-01-01

    Continuous dopaminergic delivery is recognized for the capacity to ameliorate symptoms in Parkinson's disease (PD). In advanced PD the short comings of orally administered Levodopa/Carbidopa include fluctuations resulting in unstable effect and dyskinesia. Levodopa/Carbidopa intestinal gel, LCIG......, (Duodopa®, Abbott Laboratories) is delivered continuously through a percutaneous endoscopic gastrostomy with the inner tube placed in the duodenum by means of a device (CADD legacy Duodopa pump (CE 0473)). The therapy implies continuous dopaminergic delivery directly to the duodenum and is therefore...... unaffected by gastric emptying and represents a major adjuvant in the treatment of advanced PD with significant improvement in motor and non-motor symptoms. The aim of this paper is to suggest the prerequisites for a LCIG clinic and propose a feasible set-up and lean organization of a movement disorder...

  13. Assessment of the 2-d gel-based proteomics application of clinically archived formalin-fixed paraffin embedded tissues.

    Science.gov (United States)

    Davalieva, Katarina; Kiprijanovska, Sanja; Polenakovic, Momir

    2014-04-01

    Hospital tissue repositories possess a vast and valuable supply of disease samples with matched retrospective clinical information. Detection and characterization of disease biomarkers in formalin-fixed paraffin-embedded (FFPE) tissues will greatly aid the understanding of the diseases mechanisms and help in the development of diagnostic and prognostic markers. In this study, the possibility of using full-length proteins extracted from clinically archived FFPE tissues in two-dimensional (2-D) gel-based proteomics was evaluated. The evaluation was done based on two types of tumor tissues (breast and prostate) and two extraction protocols. The comparison of the 2-D patterns of FFPE extracts obtained by two extraction protocols with the matching frozen tissue extracts showed that only 7-10% of proteins from frozen tissues can be matched to proteins from FFPE tissues. Most of the spots in the 2-D FFPE's maps had pl 4-6, while the percentages of proteins with pl above 6 were 3-5 times lower in comparison to the fresh/frozen tissue. Despite the three-fold lower number of the detected spots in FFPE maps compared to matched fresh/frozen maps, 67-78% of protein spots in FFPE could not be matched to the corresponding spots in the fresh/frozen tissue maps indicating irreversible protein modifications. In conclusion, the inability to completely reverse the cross-linked complexes and overcome protein fragmentation with the present day FFPE extraction methods stands in the way of effective use of these samples in 2-D gel based proteomics studies.

  14. Treatment of pain in fibromyalgia patients with testosterone gel: Pharmacokinetics and clinical response.

    Science.gov (United States)

    White, Hillary D; Brown, Lin A J; Gyurik, Robert J; Manganiello, Paul D; Robinson, Thomas D; Hallock, Linda S; Lewis, Lionel D; Yeo, Kiang-Teck J

    2015-08-01

    To test our hypothesis that testosterone deficiency plays an important role in chronic pain, a Phase I/II pilot study was initiated with 12 fibromyalgia patients to verify that a daily dose for 28days with transdermal testosterone gel would 1) significantly and safely increase mean serum testosterone concentrations from low baseline levels to mid/high-normal levels, and 2) effectively treat the pain and fatigue symptoms of fibromyalgia. Pharmacokinetic data confirmed that serum free testosterone concentrations were raised significantly above baseline levels, by assessment of maximum hormone concentration (Cmax) and area under the curve (AUC) parameters: free testosterone Cmax was significantly raised from a mean of 2.64pg/mL to 3.91pg/mL (pfibromyalgia by patient questionnaire and tender point exam demonstrated significant change in: decreased muscle pain, stiffness, and fatigue, and increased libido during study treatment. These results are consistent with the hypothesized ability of testosterone to relieve the symptoms of fibromyalgia. Symptoms not tightly related to fibromyalgia were not improved.

  15. A clinical and SEM evaluation of the efficiency of sofscale gel and hand scaling and hand scaling alone.

    Science.gov (United States)

    Thomas, K; Vandana, K L; Reddy, V Ramesh

    2002-01-01

    The purpose of this study is to compose between hand scaling with abd without the calculus solvent gel (sofscale) and ultrasonic instrumentation at clinical and SEM level. 30 patients belonging to the age group of 17-50 year were selected. Patients selected were subjected to three different scaling modalities namely hand scaling (control), hand scaling using sofscale (Experimental quadrant A) and ultrasonic scaling (Experimental quadrant B), in three different quadrants. Case report forms were used to document the tooth sensitivity, soft tissue pain after scaling, patient preference of instrumentation, ease of calculus removal, patient comfort, soft tissue irritation, time taken for scaling, Bleeding while scaling, pre and post operative sulcus bleeding index. In addition to the clinical criteria, the teeth treated were extracted and evaluated using the scanning electron microscope to show potential effects on cemntal surfaces. No difference in tooth sensitivity was appreciated between control and experimental quadrant A. There was a higher degree of tooth sensitivity when treated with ultrasonic. Patients in control group appreciated a higher degree of soft tissue pain. Hand scaling using softscale produced a lesser amount of pain and treatment with ultrasoincs was the least painful. Most of the patients preferred ultrasonic scaling (70%) Calculus removal was easier. Hand scaling using sofscale gel results in more patient comfort when compared to hand scaling alone. There was no significant difference in patient comfort between handscaling using sofscale and ultrasonic scaling. The percentage of reduction of sulcus bleeding index showed no difference between the 3 scaling modalities SEM evaluation revealed that there was no significant difference the 3 scaling modalities in relation to residual calculus, cleaning efficiency and damage to the root surface. This study concluded that treatment with sofscale gel appears to be safe and effective method for removal

  16. Integration in a multilayer microfluidic chip of 8 parallel cell sorters with flow control by sol-gel transition of thermoreversible gelation polymer.

    Science.gov (United States)

    Sugino, Hirokazu; Arakawa, Takahiro; Nara, Yuki; Shirasaki, Yoshitaka; Ozaki, Kazuto; Shoji, Shuichi; Funatsu, Takashi

    2010-10-01

    Microfluidic systems have significant implications in the field of cell separation since they could provide platforms with inexpensive, disposable and sterile structures. Here, we present a novel strategy to integrate microfluidic sorters into a single chip for high throughput sorting. Our parallel sorter consists of a microfluidic chip with a three-dimensional channel network that utilizes flow switching by a heat-induced sol-gel transition of thermoreversible gelation polymer. The 8 parallel sheathed sample flows were realized by injecting sample and buffer solutions into only 2 inlets. The sheathed flows enabled disposal of unwanted sample waste without laser irradiation, and collection of wanted sample upon irradiation. As an application of the sorter, two kinds of fluorescent microspheres were separated with recovery ratio and purity of 70% or 90% at throughputs of about 100 or 20 particles per second, respectively. Next, Escherichia coli cells expressing green fluorescent protein were separated from those expressing DsRed with recovery ratio and purity of 90% at a throughput of about 20 cells per second. PMID:20689871

  17. Study the effect of ion-complex on the properties of composite gel polymer electrolyte based on Electrospun PVdF nanofibrous membrane

    International Nuclear Information System (INIS)

    In this paper, nanofibrous membranes based on poly(vinylidene fluoride) (PVdF) doped with ion-complex (SiO2-PAALi) were prepared by electrospinning technique and the corresponding composite gel-polymer electrolytes (CGPEs) were obtained after being activated in liquid electrolyte. The microstructure, physical and electrochemical performances of the nanofibrous membranes and the corresponding CGPEs were studied by various measurements such as Fourier Transform Infrared Spectroscopy(FTIR), Scanning Electron Microscope (SEM), Differential Scanning Calorimetry (DSC), Thermal Gravimetric Analysis (TGA), Stress-strain test, Linear Sweep Voltammetry (LSV), AC impedance measurement and Charge/discharge cycle test. As to the ion-complex doped nanofibrous membranes, PVdF can provide mechanical support with network structure composed of fully interconnection; while the ion-complexes are absorbed onto the surface of the PVdF nanofibers evenly instead of being aggregated. With the help of doped ion-complex, the prepared nanofibrous membranes present good liquid electrolyte absorbability, excellent mechanical performance, and high decomposition temperature. For the corresponding CGPEs, they possess high ionic conductivity, wide electrochemical window, and good charge/discharge cycle performance

  18. Improved photovoltaic performance of inverted polymer solar cells through a sol-gel processed Al-doped ZnO electron extraction layer.

    Science.gov (United States)

    Kim, Jun Young; Cho, Eunae; Kim, Jaehoon; Shin, Hyeonwoo; Roh, Jeongkyun; Thambidurai, Mariyappan; Kang, Chan-mo; Song, Hyung-Jun; Kim, SeongMin; Kim, Hyeok; Lee, Changhee

    2015-09-21

    We demonstrate that nanocrystalline Al-doped zinc oxide (n-AZO) thin film used as an electron-extraction layer can significantly enhance the performance of inverted polymer solar cells based on the bulk heterojunction of poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl] (PCDTBT) and [6,6]-phenyl C(71)-butyric acid methyl ester (PC(70)BM). A synergistic study with both simulation and experiment on n-AZO was carried out to offer a rational guidance for the efficiency improvement. As a result, An n-AZO film with an average grain size of 13 to 22 nm was prepared by a sol-gel spin-coating method, and a minimum resistivity of 2.1 × 10(-3) Ω·cm was obtained for an Al-doping concentration of 5.83 at.%. When an n-AZO film with a 5.83 at.% Al concentration was inserted between the ITO electrode and the active layer (PCDTBT:PC(70)BM), the power conversion efficiency increased from 3.7 to 5.6%. PMID:26406762

  19. Sol-gel derived multiwalled carbon nanotubes ceramic electrode modified with molecularly imprinted polymer for ultra trace sensing of dopamine in real samples

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Bhim Bali, E-mail: prof.bbpd@yahoo.com [Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005 (India); Kumar, Deepak; Madhuri, Rashmi; Tiwari, Mahavir Prasad [Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221 005 (India)

    2011-08-01

    Highlights: > MWCNTs-CE was prepared by silane acrylate which provides a nanometer thin MIP film. > The sensor was modified by iniferter and MIP using 'surface grafting-from approach'. > A comparative study was performed between differentially designed ceramic electrodes. > The sensor can detect dopamine in real samples with LODs (0.143-0.154 ng mL{sup -1}). - Abstract: A new class of composite electrodes made of sol-gel derived ceramic-multiwalled carbon nanotubes is used for the growth of a nanometer thin film adopting 'surface grafting-from approach'. For this the multiwalled carbon nanotubes-ceramic electrode surface is first modified with an iniferter (benzyl N,N-diethyldithiocarbamate) and then dopamine imprinted polymer, under UV irradiation, for differential pulse anodic stripping voltammetric sensing of dopamine in aqueous, blood serum, cerebrospinal fluid, and pharmaceutical samples (detection limit 0.143-0.154 ng mL{sup -1}, 3{sigma}), without any cross reactivity, interferences and false-positive contributions. Such composite electrodes offer higher stability, electron kinetics, and renewable porous surface of larger electroactive area (with insignificant capacitance) than carbon ceramic electrodes. Additional cyclic voltammetry (stripping mode) and chronocoulometry experiments were performed to explore electrodics and kinetics of electro-oxidation of dopamine.

  20. The potential of incorporation of binary salts and ionic liquid in P(VP-co-VAc) gel polymer electrolyte in electrochemical and photovoltaic performances

    Science.gov (United States)

    Ming, Ng Hon; Ramesh, S.; Ramesh, K.

    2016-06-01

    In this study, dye-sensitized solar cells (DSSCs) has been assembled with poly(1-vinylpyrrolidone-co-vinyl acetate) (P(VP-co-VAc)) gel polymer electrolytes (GPEs) which have been incorporated with binary salt and an ionic liquid. The potential of this combination was studied and reported. The binary salt system GPEs was having ionic conductivity and power conversion efficiency (PCE) that could reach up to 1.90 × 10‑3 S cm‑1 and 5.53%, respectively. Interestingly, upon the addition of the ionic liquid, MPII into the binary salt system the ionic conductivity and PCE had risen steadily up to 4.09 × 10‑3 S cm‑1 and 5.94%, respectively. In order to know more about this phenomenon, the electrochemical impedance studies (EIS) of the GPE samples have been done and reported. Fourier transform infrared studies (FTIR) and thermogravimetric analysis (TGA) have also been studied to understand more on the structural and thermal properties of the GPEs. The Nyquist plot and Bodes plot studies have been done in order to understand the electrochemical properties of the GPE based DSSCs and Tafel polarization studies were done to determine the electrocatalytic activity of the GPE samples.

  1. 互穿聚合物网络凝胶调剖堵水剂的研究进展%Research progress of interpenetrating polymer network gel profile control and water plugging agent

    Institute of Scientific and Technical Information of China (English)

    李翠霞; 覃孝平

    2014-01-01

    Researehes both foreign and domestie on the interpenetrating polymer network gel profile eon-trol and water plugging agent are reviewed. The preparation methods,raw materials,formulas,properties and field applieation effeet of the interpenetrating polymer network gel profile eontrol and water plugging agent are diseussed. At the same time,the development trend of interpenetrating polymer network gel pro-file eontrol and water plugging agent is illustrated. The researeh results have eertain referenee value and guiding signifieanee to improve water flooding development effeet of high water eut oil field.%综述了互穿聚合物网络凝胶调剖堵水剂的国内外研究现状;阐述了互穿聚合物网络凝胶调剖堵水剂的制备方法、原料、配方、性能以及现场应用效果;同时指出了互穿聚合物网络凝胶调剖堵水剂的发展趋势。研究成果对改善高含水油田注水开发效果具有一定的参考价值和指导意义。

  2. Hydrogen Bonded Supramolecular Polymers in Both Apolar and Aqueous Media: Self-Assembly and Reversible Conversion of Vesicles and Gels%Hydrogen Bonded Supramolecular Polymers in Both Apolar and Aqueous Media: Self-Assembly and Reversible Conversion of Vesicles and Gels

    Institute of Scientific and Technical Information of China (English)

    杜平; 孔军; 王贵涛; 赵新; 李光玉; 蒋锡夔; 黎占亭

    2011-01-01

    In a preliminary letter (Tetrahedron Lett. 2010, 51, 188), we reported two new hydrazide-based quadruple hydrogen-bonding motifs, this is, two monopodal (la and lb) and five dipodal (2a, 2b and 3a--3c) aromatic hydrazide derivatives, and the formation of supramolecular polymers and vesicles from the dipodal motifs in hydrocarbons. In this paper, we present a full picture on the properties of these hydrogen-bonding motifs with an emphasis on their self-assembling behaviors in aqueous media. SEM, AFM, TEM and fluorescent micrographs indicate that all the dipodal compounds also form vesicles in polar methanol and water-methanol (up to 50% of water) mixtures. Control experiments show that lb does not form vesicles in same media. Addition of lb to the solution of the dipodal compounds inhibits the latter's capacity of forming vesicles. At high concentrations, 3b and 3c also gelate discrete solvents, including hydrocarbons, esters, methanol, and methanol-water mixture. Concentration-dependent SEM investigations reveal that the vesicles of 3b and 3c fuse to form gels and the gel of 3c can de-aggregate to form the vesicles reversibly.

  3. Comparison of effectiveness of curcumin with triamcinolone acetonide in the gel form in treatment of minor recurrent aphthous stomatitis: A randomized clinical trial.

    Science.gov (United States)

    Deshmukh, Radha A.; Bagewadi, Anjana S.

    2014-01-01

    Introduction: Recurrent aphthous stomatitis (RAS) is an unfortunately most common disease occurring in oral cavity. Although the lesion is usually self-limited, its painful presentation, high frequency of occurrence, and multifactorial etiology leads to significant morbidity. So, an efficient therapeutic strategy is needed to provide relief to the patients. Aim: To assess and compare the efficacy of Curcumin with Triamcinolone acetonide in the gel form in treatment of minor RAS. Materials and Methods: As a randomized clinical trial, 60 patients of either sex with clinically diagnosed RAS were randomly divided into 2 groups-Curcumin gel group (Group I) and Triamcinolone Acetonide gel group (Group II). Patients in either group were asked to apply the gel three times a day on each ulcer. Assessment of efficacy of gel was done on the basis of time required for regression in pain, size, and number of the ulcers. Results: The results showed significant difference in size, pain, number, and duration of ulcers in Group I and Group II within a period of 7 days. However, no significant difference was noted in both the groups in the treatment of RAS. To evaluate the efficacy, Mann-Whitney U test was used and statistical analysis was done using Statistical Package for the Social Sciences (SPSS) 19 software. Conclusion: Curcumin has strong antioxidant, with anti-inflammatory, immunomodulatory and analgesic properties, which according to the results obtained from the present study, can be used as an effective alternative to steroids in treatment of RAS. PMID:25126527

  4. Composite Gel Polymer Electrolyte Based on Poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) with Modified Aluminum-Doped Lithium Lanthanum Titanate (A-LLTO) for High-Performance Lithium Rechargeable Batteries.

    Science.gov (United States)

    Le, Hang T T; Ngo, Duc Tung; Kalubarme, Ramchandra S; Cao, Guozhong; Park, Choong-Nyeon; Park, Chan-Jin

    2016-08-17

    A composite gel polymer electrolyte (CGPE) based on poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) polymer that includes Al-doped Li0.33La0.56TiO3 (A-LLTO) particles covered with a modified SiO2 (m-SiO2) layer was fabricated through a simple solution-casting method followed by activation in a liquid electrolyte. The obtained CGPE possessed high ionic conductivity, a large electrochemical stability window, and interfacial stability-all superior to that of the pure gel polymer electrolyte (GPE). In addition, under a highly polarized condition, the CGPE effectively suppressed the growth of Li dendrites due to the improved hardness of the GPE by the addition of inorganic A-LLTO/m-SiO2 particles. Accordingly, the Li-ion polymer and Li-O2 cells employing the CGPE exhibited remarkably improved cyclability compared to cells without CGPE. In particular, the CGPE as a protection layer for the Li metal electrode in a Li-O2 cell was effective in blocking the contamination of the Li electrode by oxygen gas or impurities diffused from the cathode side while suppressing the Li dendrites. PMID:27463563

  5. Bridging the Gap between Preclinical and Clinical Microbicide Trials: Blind Evaluation of Candidate Gels in Murine Models of Efficacy and Safety

    OpenAIRE

    Theodore J Segarra; Esra Fakioglu; Natalia Cheshenko; Wilson, Sarah S; Pedro M M Mesquita; Doncel, Gustavo F.; Herold, Betsy C.

    2011-01-01

    BACKGROUND: Despite significant protection in preclinical studies, cellulose sulfate (CS) failed to protect women against HIV-1/2 and was associated with a trend toward increased HIV-1 acquisition in one of the clinical trials. These results highlight the need for preclinical tests more predictive of clinical outcomes. The objective of this study was to test coded vaginal gels, including CS, in murine models of safety and efficacy to determine the models' utility for evaluating future product...

  6. PVA-H3 PO4凝胶聚合物电解质膜的制备及性能研究%Preparation of PVA-H3 PO4 Gel Polymer Electrolyte Membranes and Their Properties

    Institute of Scientific and Technical Information of China (English)

    张飞; 田琦峰; 李长春

    2016-01-01

    以磷酸作为交联引发剂和质子源,用戊二醛(GA)交联聚乙烯醇(PVA)制备 PVA-H3 PO4凝胶聚合物电解质膜。采用 X-射线衍射(XRD)、傅立叶变换红外光谱(FTIR)、热重分析(TGA)对制备的凝胶聚合物电解质膜进行了表征,并采用交流阻抗法研究了凝胶聚合物电解质膜的导电性能,分析了磷酸含量对凝胶聚合物电解质膜质子电导率的影响。结果表明,加入磷酸后,PVA结构由晶态向非晶态转变。随着 H3 PO4含量的增加,凝胶聚合物电解质膜的质子电导率先增大后减小;当PVA与 H3 PO4的质量比为1∶6时,在室温下其质子电导率可达0.093 S·cm-1,并且具有良好的电化学稳定性。%Using H3 PO4 as a cross-linking initiator and proton soure,PVA-H3 PO4 gel polymer electrolyte membranes were prepared by cross-linking glutaraldehyde(GA)with polyvinyl alcohol(PVA).The prepared gel polymer electrolyte membranes were characterized by X-ray diffraction(XRD),Fourier transform infrared spec-troscopy(FTIR)and thermogravimetric analysis(TGA).The conductivity of the gel polymer electrolyte mem-branes was investigated by an AC impedance method,and the effect of H3 PO4 content on the proton conductivi-ty of the gel polymer electrolyte membranes was also studied.Results showed that the structure of PVA trans-formed from crystalline state to amorphous state after addition of H3 PO4 .The proton conductivity of the gel polymer electrolyte membranes increased first and then decreased with the increase of H3 PO4 content.When the mass ratio of PVA and H3 PO4 was 1∶6,the proton conductivity reached 0.093 S·cm-1 at room temperature. Meanwhile,it had good electrochemical stability.

  7. Enhanced performance of a quasi-solid-state dye-sensitized solar cell with aluminum nitride in its gel polymer electrolyte

    KAUST Repository

    Huang, Kuan-Chieh

    2011-08-01

    The effects of incorporation of aluminum nitride (AlN) in the gel polymer electrolyte (GPE) of a quasi-solid-state dye-sensitized solar cell (DSSC) were studied in terms of performance of the cell. The electrolyte, consisting of lithium iodide (LiI), iodine (I2), and 4-tert-butylpyridine (TBP) in 3-methoxypropionitrile (MPN), was solidified with poly(vinyidene fluoride-co-hexafluoro propylene) (PVDF-HFP). The 0.05, 0.1, 0.3, and 0.5 wt% of AlN were added to the electrolyte for this study. XRD analysis showed a reduction of crystallinity in the polymer PVDF-HFP for all the additions of AlN. The DSSC fabricated with a GPE containing 0.1 wt% AlN showed a short-circuit current density (JSC) and power-conversion efficiency (η) of 12.92±0.54 mA/cm2 and 5.27±0.23%, respectively, at 100 mW/cm2 illumination, in contrast to the corresponding values of 11.52±0.21 mA/cm2 and 4.75±0.08% for a cell without AlN. The increases both in JSC and in η of the promoted DSSC are attributed to the higher apparent diffusion coefficient of I- in its electrolyte (3.52×10-6 cm2/s), compared to that in the electrolyte without AlN of a DSSC (2.97×10-6 cm 2/s). At-rest stability of the quasi-solid-state DSSC with 0.1 wt% of AlN was found to decrease hardly by 5% and 7% at room temperature and at 40 °C, respectively, after 1000 h duration. The DSSC with a liquid electrolyte showed a decrease of about 40% at room temperature, while it virtually lost its performance in about 150 h at 40 °C. Explanations are further substantiated by means of electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and by porosity measurements. © 2010 Elsevier B.V.

  8. Direct surface modification of high-voltage LiCoO2 cathodes by UV-cured nanothickness poly(ethylene glycol diacrylate) gel polymer electrolytes

    International Nuclear Information System (INIS)

    Highlights: • Direct surface modification of high-voltage LCO cathode by UV-cured PEGDA GPE. • Conformal PEGDA nanocoating layer is formed on LCO surface. • Preformed architecture of LCO cathode is not disrupted by PEGDA coating layer. • PEGDA-LCO cathode improves high-voltage cycling performance and thermal stability. • PEGDA nanocoating layer serves as a new ion-conductive protection film. -- Abstract: In the development of high-voltage lithium-ion batteries, unwanted interfacial side reactions between delithiated cathode materials and liquid electrolytes pose a formidable challenge that needs to be urgently resolved. In this study, as a simple and effective approach to improve cell performance and thermal stability of high-voltage cells, we demonstrate direct surface modification of a cathode by UV-cured nanothickness poly(ethylene glycol diacrylate) (PEGDA) gel polymer electrolyte (GPE). Herein, the UV-crosslinking of EGDA oligomers is conducted directly on as-formed cathode (LiCoO2 (LCO) is chosen as a model system), instead of application to LCO powders. This unusual coating process allows the successful formation of the conformal PEGDA nanocoating layer on the LCO surface without disrupting the preformed physical architecture of the LCO cathode (specifically, electronic networks and porous structure to be filled with liquid electrolyte). Owing to the structural novelty, the PEGDA-coated LCO cathode improves the cycling performance of high-voltage (=4.4 V) cells and suppresses the exothermic reaction between the delithiated LCO and liquid electrolyte, as compared to the pristine LCO cathode. These results underline that the conformal PEDGDA nanocoating layer proposed herein acts as a new ion-conductive protection film that effectively mitigates the undesired interfacial side reactions

  9. Cr3+聚合物凝胶成胶效果及其影响因素%Study on gelling effect of Cr3+polymer gel and its influence factors

    Institute of Scientific and Technical Information of China (English)

    卢祥国; 谢坤; 曹豹; 陈欣

    2015-01-01

    Although high-concentration polymer has strong viscoelasticity, there exist the compatibility problems between pol-ymer molecules aggregate size and reservoir rock pore size during its practical application. According to the geological charac-teristics and fluid properties of Daqing Oilfield reservoir, the viscoelasticity and oil displacement efficiency of the intramolec-ular cross-link polymer gel system were investigated after it was selected by orthogonal experiment through evaluating seepage characteristics, with core flow experiment and oil displacement experiment. It was found that intramolecular cross-link poly-mer gel system with smaller molecular aggregate, higher resistance coefficient and residual resistance coefficient can be ob-tained by regulating polymer concentration, water solution salinity and polymer/Cr3+. Once intramolecular cross-link reacted in polymer solution, on the one hand, transmission migration ability of polymer molecular clew is enhanced, and its rigidity is also improved. In this way, deformation ability of the polymer molecular clew is weakened when it flows through core pore, which can enhance the retention ability, increase the injection pressure and enlarge sweep volume effectively. On the other hand, the viscoelasticity and first normal stress difference of polymer gel system are improved, as well as the washing oil effi-ciency. The above two aspects insure jointly Cr3+ polymer gel has higher oil displacement efficiency.%高质量浓度聚合物具有较强的黏弹性,但应用中有时会出现聚合物分子聚集体尺寸与油藏岩石孔隙配伍性较差的问题。针对大庆油田储层地质特征和流体性质,通过岩心流动性实验和驱油实验,以渗流特性为评价指标,利用正交试验优选出分子内交联聚合物凝胶体系后,研究凝胶体系黏弹性和驱油效率。结果表明:调节聚合物质量浓度、配制水矿化度、w(聚/Cr3+)可获得分子聚集体尺寸较小

  10. CONFORMANCE IMPROVEMENT USING GELS

    Energy Technology Data Exchange (ETDEWEB)

    Randall S. Seright

    2004-09-30

    This report describes work performed during the third and final year of the project, ''Conformance Improvement Using Gels.'' Corefloods revealed throughput dependencies of permeability reduction by polymers and gels that were much more prolonged during oil flow than water flow. This behavior was explained using simple mobility ratio arguments. A model was developed that quantitatively fits the results and predicts ''clean up'' times for oil productivity when production wells are returned to service after application of a polymer or gel treatment. X-ray computed microtomography studies of gels in strongly water-wet Berea sandstone and strongly oil-wet porous polyethylene suggested that oil penetration through gel-filled pores occurs by a gel-dehydration mechanism, rather than gel-ripping or gel-displacement mechanisms. In contrast, analysis of data from the University of Kansas suggests that the gel-ripping or displacement mechanisms are more important in more permeable, strongly water-wet sandpacks. These findings help to explain why aqueous gels can reduce permeability to water more than to oil under different conditions. Since cement is the most commonly used material for water shutoff, we considered when gels are preferred over cements. Our analysis and experimental results indicated that cement cannot be expected to completely fill (top to bottom) a vertical fracture of any width, except near the wellbore. For vertical fractures with apertures less than 4 mm, the cement slurry will simply not penetrate very far into the fracture. For vertical fractures with apertures greater than 4 mm, the slurry may penetrate a substantial distance into the bottom part of the fracture. However, except near the wellbore, the upper part of the fracture will remain open due to gravity segregation. We compared various approaches to plugging fractures using gels, including (1) varying polymer content, (2) varying placement (extrusion) rate

  11. Avaliação clínica e laboratorial do gel da Uncaria tomentosa (Unha de Gato sobre candidose oral Clinical and laboratorial evaluation of Uncaria tomentosa (Cat's Claw gel on oral candidiasis

    Directory of Open Access Journals (Sweden)

    Leonardo Costa de Almeida Paiva

    2009-06-01

    Full Text Available Na odontologia, a fitoterapia já vem sendo utilizada com sucesso há vários anos. Trata-se de um meio terapêutico que apresenta como vantagem sobre as medicações alopáticas o fato de apresentar reações adversas mínimas. A Uncaria tomentosa é uma planta indígena da floresta Amazônica e de outras áreas tropicais da América do Sul e Central. Tem aplicação no tratamento de diversas patologias, entre elas a candidose. Este trabalho avalia clínico e laboratorialmente a ação do gel da Uncaria tomentosa em pacientes portadores de candidose na cavidade oral. Foram selecionados 20 pacientes que apresentaram clínico e laboratorialmente infecção pelo Candida. Os mesmos foram divididos em 2 grupos. O grupo-teste (Uncaria tomentosa/Imuno-Max Gel, composto por 10 pacientes, foi orientado a utilizar o gel da Uncaria tomentosa, sobre as lesões na cavidade oral, 3x ao dia por um período de 14 dias. O grupo-controle (Miconazol/Daktarin Gel utilizou a medicação da mesma forma prescrita para o grupo-teste. Após o período de tratamento, os pacientes retornaram para nova avaliação clínica e laboratorial. A Uncaria tomentosa mostrou ser um fitofármaco promissor na odontologia, apresentando vantagem sobre o miconazol de não ter provocado reações adversas nos pacientes, uma vez que, 40% dos pacientes do grupo-controle, apresentaram reações indesejáveis.In dentistry, the phytotherapy is already being used successfully for some years now. It is about a promising therapeutical way in the pharmaceutical field, having as advantage on pharmacotherapy medications the fact to present minimum adverse reactions. The Uncaria tomentosa is an aboriginal plant of the Amazonian forest and other tropical areas of the South and Central America. It has application in the treatment of several pathologies, including candidiasis. This work evaluates, clinical and laboratorial, the action of the Uncaria tomentosa gel in the oral cavity candidiasis

  12. Clinical developments of chemotherapeutic nanomedicines: Polymers and liposomes for delivery of camptothecins and platinum (II) drugs

    KAUST Repository

    Kieler-Ferguson, Heidi M.

    2013-01-17

    For the past 40 years, liposomal and polymeric delivery vehicles have been studied as systems capable of modulating the cytotoxicity of small molecule chemotherapeutics, increasing tumor bearing animal survival times, and improving drug targeting. Although a number of macromolecular-drug conjugates have progressed to clinical trials, tuning drug release to maintain efficacy in conjunction with controlling drug toxicity has prevented the clinical adoption of many vehicles. In this article, we review the motivations for and approaches to polymer and liposomal delivery with regard to camptothecin and cisplatin delivery. WIREs Nanomed Nanobiotechnol 2013, 5:130-138. doi: 10.1002/wnan.1209 For further resources related to this article, please visit the WIREs website. Conflict of interest: Drs Kieler-Ferguson and Fréchet declare no conflicts of interest. Dr Szoka is the founder of a liposome drug delivery company that is not working on any of the compounds mentioned in this article. © 2013 Wiley Periodicals, Inc.

  13. Effects of Standardised Fermented Papaya Gel on Clinical Symptoms, Inflammatory Cytokines, and Nitric Oxide Metabolites in Patients with Chronic Periodontitis: An Open Randomised Clinical Study.

    Science.gov (United States)

    Kharaeva, Zaira F; Zhanimova, Lyana R; Mustafaev, Magomet Sh; De Luca, Chiara; Mayer, Wolfgang; Chung Sheun Thai, Jeffrey; Tiew Siok Tuan, Rebecca; Korkina, Liudmila G

    2016-01-01

    The clinical efficacy of topical administration of standardised fermented papaya gel (SFPG), known to have antioxidant and anti-inflammatory properties, versus conventional therapy was evaluated in a group of 84 patients with moderate-to-severe periodontitis, randomly assigned to control group (n = 45) undergoing traditional pharmacologic/surgical protocols or to experimental group (n = 39), additionally treated with intragingival pocket SFPG (7 g) applications (15 min daily for 10 days). Patients undergoing SFPG treatment showed significant (P < 0.05), durable improvement of three major clinical indices of disease severity: reduced bleeding (day 7), plaque and gingival conditions (day 14), and consistent gingival pocket depth reduction (day 45). Proinflammatory nitric oxide metabolites reached normal values in plasma (day 14) and gingival crevicular fluid (GCF) at day 45 with SFPG applications compared to controls that did not reach normalisation. Levels of highly increased proinflammatory (IL-1B, IL-6) and suppressed anti-inflammatory (IL-10) cytokines normalised in the SFPG group by days 14 (plasma) and 45 (GCF), but never in the control group. Although not acting directly as antibiotic, SFPG acted in synergy with human granulocytes blocking adaptive catalase induction in S. aureus in response to granulocyte-derived oxidative stress, thus enhancing intracellular bacterial killing. PMID:26977121

  14. Effects of Standardised Fermented Papaya Gel on Clinical Symptoms, Inflammatory Cytokines, and Nitric Oxide Metabolites in Patients with Chronic Periodontitis: An Open Randomised Clinical Study

    Directory of Open Access Journals (Sweden)

    Zaira F. Kharaeva

    2016-01-01

    Full Text Available The clinical efficacy of topical administration of standardised fermented papaya gel (SFPG, known to have antioxidant and anti-inflammatory properties, versus conventional therapy was evaluated in a group of 84 patients with moderate-to-severe periodontitis, randomly assigned to control group (n=45 undergoing traditional pharmacologic/surgical protocols or to experimental group (n=39, additionally treated with intragingival pocket SFPG (7 g applications (15 min daily for 10 days. Patients undergoing SFPG treatment showed significant (P<0.05, durable improvement of three major clinical indices of disease severity: reduced bleeding (day 7, plaque and gingival conditions (day 14, and consistent gingival pocket depth reduction (day 45. Proinflammatory nitric oxide metabolites reached normal values in plasma (day 14 and gingival crevicular fluid (GCF at day 45 with SFPG applications compared to controls that did not reach normalisation. Levels of highly increased proinflammatory (IL-1B, IL-6 and suppressed anti-inflammatory (IL-10 cytokines normalised in the SFPG group by days 14 (plasma and 45 (GCF, but never in the control group. Although not acting directly as antibiotic, SFPG acted in synergy with human granulocytes blocking adaptive catalase induction in S. aureus in response to granulocyte-derived oxidative stress, thus enhancing intracellular bacterial killing.

  15. Green synthesis of silver nanoparticles by Chrysanthemum morifolium Ramat. extract and their application in clinical ultrasound gel

    Directory of Open Access Journals (Sweden)

    He Y

    2013-05-01

    well as a strong antibacterial activity against gram-negative bacteria, as compared to gram-positive bacteria with a dose-dependent effect, thus providing a clinical ultrasound gel with bactericidal property for prevention of cross infections.Keywords: silver nanoparticles, green synthesis, Chrysanthemum morifolium Ramat., bactericidal activity, ultrasound gel

  16. Development of PDRESS (Patient Specific Dose Real Evaluation Systems) using a TENOMAG Gel and Optical CT (VISTA TM) in Clinical IMRT Prostate Case

    Science.gov (United States)

    Lee, Suk; Shim, Jang Bo; Chang, Kyung Hwan; Yuanjie; Cao; Yi, Jaeyoun; Park, Jinwoo; Cho, Sam Ju; Lee, Sang Hoon; Huh, HyunDo; Cho, Kwang Hwan; Min, Chul Kee; Yang, Dae Sik; Park, Young Je; Yoon, Won Seob; Kim, Chul Yong

    2010-11-01

    The aims of this study, we present the preliminary results of 3 dimensional dose evaluation software (PDRESS, patient specific dose real evaluation systems). In this work, we compared planned 3D dose distribution with measured 3D dose distribution using a novel normoxic polymer gel dosimeter (TENOMAG) and a commercial cone-beam optical CT scanner (VISTATM, Modus Medical Devices, Inc., London, ON, Canada) to verify the 3D dose distribution in intensity-modulated radiation therapy (IMRT) prostate case. And we developed PDRESS using the Xelis Flatform which is developed by INFINITT Corporation is used to display the 3D dose distribution by loading the DICOM RT Data which is exported from RTP and optical-CT reconstructed VFF file. Data analysis is achieved by comparing the RTP data with the VFF data using profile, gamma map, and DTA. The profiles showed good agreement between RTP data, gel dosimeter, and gamma distribution and the precision of the dose distribution is within ± 5%. The results from this study show that there are no significantly discrepancies between the calculated dose distribution from treatment plan and the measured dose distribution from a TENOMAG gel scanned with an optical CT scanner. The 3D dose evaluation software (PDRESS) which is developed in this study evaluates the accuracy of the three dimensional dose distributions.

  17. Molecular Weight and Branching Distribution Modeling in Radical Polymerization with Transfer to Polymer and Scission Under Gel Conditions and Allowing for Multiradicals

    NARCIS (Netherlands)

    N. Yaghini; P. Iedema

    2014-01-01

    A population balance model for the prediction of molecular weight distribution (MWD) in a continuous stirred tank reactor (CSTR) has been developed accounting for multiradicals and gel formation in the framework of Galerkin-FEM. In the absence of recombination, gel does not form, but accounting for

  18. Self-assembling polymer micelle/clay nanodisk/doxorubicin hybrid injectable gels for safe and efficient focal treatment of cancer.

    Science.gov (United States)

    Nagahama, Koji; Kawano, Daichi; Oyama, Naho; Takemoto, Ayaka; Kumano, Takayuki; Kawakami, Junji

    2015-03-01

    The purpose of this study was to fabricate a safe and effective doxorubicin (DOX)-delivery system for focal cancer chemotherapy. A novel biodegradable injectable gel was developed through self-assembly of poly(D,L-lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(D,L-lactide-co-glycolide) (PLGA-PEG-PLGA) copolymer micelles, clay nanodisks (CNDs), and DOX. We discovered that DOX loaded in the hybrid gels acts as an anticancer drug and as a building block to organize new gel networks. Accordingly, long-term sustained release of DOX from hybrid injectable gels without initial burst release was achieved. Moreover, it was revealed that the DOX incorporated into gel networks controls its own release profile. This hybrid injectable gel is a self-controlled drug release system, which is a novel concept in controlled drug release. Importantly, a single injection of PLGA-PEG-PLGA/CND/DOX hybrid gel provides long-term sustained antitumor activity in vivo against human xenograft tumors in mice, suggesting the potential of hybrid gels as a valuable local DOX-delivery platform for cancer focal therapy. PMID:25645815

  19. Small SRS photon field profile dosimetry performed using a PinPoint air ion chamber, a diamond detector, a novel silicon-diode array (DOSI), and polymer gel dosimetry. Analysis and intercomparison.

    Science.gov (United States)

    Pappas, E; Maris, T G; Zacharopoulou, F; Papadakis, A; Manolopoulos, S; Green, S; Wojnecki, C

    2008-10-01

    Small photon fields are increasingly used in modern radiotherapy and especially in IMRT and SRS/SRT treatments. The uncertainties related to small field profile measurements can introduce significant systematic errors to the overall treatment process. These measurements are challenging mainly due to the absence of charged particle equilibrium conditions, detector size and composition effects, and positioning problems. In this work four different dosimetric methods have been used to measure the profiles of three small 6 MV circular fields having diameters of 7.5, 15.0, and 30.0 mm: a small sensitive volume air ion chamber, a diamond detector, a novel silicon-diode array (DOSI), and vinyl-pyrrolidone based polymer gel dosimeter. The results of this work support the validity of previous findings, suggesting that (a) air ion chambers are not suitable for small field dosimetry since they result in penumbra broadening and require significant corrections due to severe charged particle transport alterations; (b) diamond detectors provide high resolution and rather accurate small field profile measurements, as long as positioning problems can be addressed and the necessary dose rate corrections are correctly applied; and (c) the novel silicon-diode array (DOSI) used in this study seems to be adequate for small field profile measurements overcoming positioning problems. Polymer gel data were assumed as reference data to which the other measurement data were compared both qualitatively and quantitatively using the gamma-index concept. Polymer gels are both phantom and dosimeter, hence there are no beam perturbation effects. In addition, polymer gels are tissue equivalent and can provide high-spatial density and high-spatial resolution measurements without positioning problems, which makes them useful for small field dosimetry measurements. This work emphasizes the need to perform beam profile measurements of small fields (for acceptance, commissioning, treatment planning

  20. Determination of Microcystin-LR in waters in the subnanomolar range by sol–gel imprinted polymers on solid contact electrodes

    OpenAIRE

    Queirós, Raquel B.; Noronha, João P. C.; Marques, P.V.S.; Fernandes, João S.; M. Goreti F. Sales

    2012-01-01

    The present work reports new sensors for the direct determination of Microcystin-LR (MC-LR) in environmental waters. Both selective membrane and solid contact were optimized to ensure suitable analytical features in potentiometric transduction. The sensing layer consisted of Imprinted Sol–Gel (ISG) materials capable of establishing surface interactions with MC-LR. Non-Imprinted Sol–Gel (NISG) membranes were used as negative control. The effects of an ionic lipophilic additive, tim...

  1. Formation of magnetite nanoparticles in poly(acrylamide) gels

    Energy Technology Data Exchange (ETDEWEB)

    Starodubtsev, Sergey G [Physics Department, M V Lomonosov Moscow State University, Leninsky Gory, Moscow 119992 (Russian Federation); Saenko, Evheniy V [Physics Department, M V Lomonosov Moscow State University, Leninsky Gory, Moscow 119992 (Russian Federation); Dokukin, Maxim E [Physics Department, M V Lomonosov Moscow State University, Leninsky Gory, Moscow 119992 (Russian Federation); Aksenov, Viktor L [Physics Department, M V Lomonosov Moscow State University, Leninsky Gory, Moscow 119992 (Russian Federation); Klechkovskaya, Vera V [Institute of Crystallography, Russian Academy of Sciences, 59 Leninsky Prospekt, Moscow 117333 (Russian Federation); Zanaveskina, Irina S [Institute of Crystallography, Russian Academy of Sciences, 59 Leninsky Prospekt, Moscow 117333 (Russian Federation); Khokhlov, Alexei R [Physics Department, M V Lomonosov Moscow State University, Leninsky Gory, Moscow 119992 (Russian Federation)

    2005-03-16

    Magnetic gels with magnetite nanoparticles incorporated in a matrix of poly(acrylamide) gel were studied. Magnetite was synthesized through coprecipitation of Fe(II) and Fe(III) in the gel phase, in the solution of linear polymer and in aqueous solution without polymer in alkaline media. The effects of network structure and of the concentration of iron salts in the swollen networks on the composition, structure and properties of magnetic gels have been studied by electron diffraction, XRD, transmission electron microscopy and vibration sample magnetometry. The average size of magnetite nanoparticles, D, is of the order of 10 nm. It decreases with the increase of polymer concentration in the gel phase. In the dried gels the particles form spherical aggregates (diameter about 150 nm), whereas in the solution of linear polymer, in the aqueous solution of iron salts and in the gel with high content of polymer the aggregates have irregular shape.

  2. Bridging the gap between preclinical and clinical microbicide trials: blind evaluation of candidate gels in murine models of efficacy and safety.

    Directory of Open Access Journals (Sweden)

    Theodore J Segarra

    Full Text Available BACKGROUND: Despite significant protection in preclinical studies, cellulose sulfate (CS failed to protect women against HIV-1/2 and was associated with a trend toward increased HIV-1 acquisition in one of the clinical trials. These results highlight the need for preclinical tests more predictive of clinical outcomes. The objective of this study was to test coded vaginal gels, including CS, in murine models of safety and efficacy to determine the models' utility for evaluating future products. METHODS: Four coded formulations, including 6% CS, 2% PRO 2000 and two placebo gels, were administered intravaginally to medroxyprogesterone-treated mice and their ability to prevent genital herpes (efficacy or to alter the susceptibility to low dose HSV challenge (safety was determined. Nonoyxnol-9 served as a positive toxicity control. RESULTS: CS and PRO 2000 significantly protected mice from genital herpes following infection with a laboratory or clinical isolate of HSV-2 introduced in buffer (p<0.001. However, protection was reduced when virus was introduced in seminal plasma. Moreover, mice were significantly more susceptible to infection with low doses of HSV-2 when challenged 12 h after the 7th daily dose of CS or nonoxynol-9 (p<0.05. The increased susceptibility was associated with alterations in epithelial architecture. CONCLUSIONS: CS prevented genital herpes when present at the time of viral challenge, but increased the rate of infection when gel was applied daily for 7 days with a vaginal wash prior to viral inoculation. The findings presumably reflect altered epithelial architecture, which may have contributed to the trend towards increased HIV observed clinically.

  3. Theory of volume transition in polyelectrolyte gels with charge regularization

    OpenAIRE

    Hua, Jing; Mitra, Mithun K; Muthukumar, M.

    2012-01-01

    We present a theory for polyelectrolyte gels that allow the effective charge of the polymer backbone to self-regulate. Using a variational approach, we obtain an expression for the free energy of gels that accounts for the gel elasticity, free energy of mixing, counterion adsorption, local dielectric constant, electrostatic interaction among polymer segments, electrolyte ion correlations, and self-consistent charge regularization on the polymer strands. This free energy is then minimized to p...

  4. Luminescent spectroscopy and structural properties of Ce3+-doped low-temperature X1-Y2SiO5 material prepared by polymer-assisted sol-gel method

    Science.gov (United States)

    Hamroun, M. S. E.; Guerbous, L.; Bensafi, A.

    2016-04-01

    Cerium (Ce3+)-doped monoclinic X1-Y2SiO5 (YSO)-type oxyorthosilicates powders were prepared by monomer and polymer-assisted sol-gel method. The present work aims to study the influence of ethylene glycol (EG) monomer, polyethylene glycol (PEG) polymer and polyvinyl alcohol (PVA) polymer, as fuels and nucleating agents for the crystallization, on structural and luminescence properties of the Ce3+ (xCe = 0.01)-doped Y2SiO5. The X-ray diffraction technique, field emission scanning electron microscopy, Fourier transform infrared spectroscopy and steady photoluminescence have been used to characterize the samples. It is found that the types of fuels affect the phase purity and luminescent characteristics of phosphors. All samples exhibit intense violet-blue asymmetric emission band in the range of 370-540 nm with a maximum intensity centered at around 420 nm assigned to the 5d → 4f (2F5/2, 2F7/2) interconfigurational transitions of Ce3+ ion in YSO nanomaterial. Finally, the vibronic coupling parameters are estimated and discussed.

  5. Silica reinforced triblock copolymer gels

    DEFF Research Database (Denmark)

    Theunissen, E.; Overbergh, N.; Reynaers, H.;

    2004-01-01

    The effect of silica and polymer coated silica particles as reinforcing agents on the structural and mechanical properties of polystyrene-poly(ethylene/butylene)-polystyrene (PS-PEB-PS) triblock gel has been investigated. Different types of chemically modified silica have been compared in order...... to evaluate the influence of the compatibility between gel and filler. Time-resolved SANS and small-angle X-ray scattering (SAXS) shows that the presence of silica particles affects the ordering of the polystyrene domains during gelsetting. The scattering pattern of silica-reinforced gels reveals strong...... scattering at very low q, but no structure and formfactor information. However, on heating above the viscoelastic to plastic transition, the 'typical' scattering pattern of the copolymer gel builds-up. All reinforced gels are strengthened by the addition of the reinforcing agent. The transitions from...

  6. ESTUDIO DE PREFORMULACIÓN PARA EL DESARROLLO DE UN GEL A BASE DE POLÍMEROS CON CAPACIDAD MUCOADHESIVA PARA ENSAYOS DE ALELOPATÍA EN INVERTEBRADOS MARINOS. Preformulation study for the development of a polymer-based gel with mucoadhesive propierties for its use in allelopathy assays in marine invertebrates

    Directory of Open Access Journals (Sweden)

    Jenny Patricia Andrade

    Full Text Available La investigación se desarrolló con el fin de implementar una metodología que permitiera la realización de ensayos de interacciones alelopáticas entre corales y esponjas, minimizando la interacción física provocada por el uso de dispositivos que producen roce y efecto abrasivo sobre los pólipos del coral. Se llevó a cabo un estudio de preformulación utilizando polímeros con características mucoadhesivas sobre mucus que recubre los pólipos de coral, con el fin de obtener un gel, incorporando en las formulaciones un extracto de la esponja Cliona delitrix. Se caracterizaron propiedades como extensibilidad y adherencia, así como la capacidad bioadhesiva de las formulaciones propuestas, considerando su comportamiento reológico. Estas mostraron una buena estabilidad física frente a las condiciones del medio marino tanto in vitro como in situ. De igual manera, se diseñó un dispositivo que facilitó la aplicación del gel sobre la superficie de los corales por parte de los buzos en el arrecife coralino. Finalmente se estudió el comportamiento de liberación al medio acuoso simulado del gel con el extracto de la esponja objeto de estudioThis study was carried out with the purpose of implementing a methodology to assess allelopathic interactions assays between corals and reef sponges reducing the physical interaction caused by the use of devices that involve abrasion and harm over the coral polyps. Was carried out a preformulation study using polymers with mucoadhesive on the mucus that cover the coral polyps, with the purpose of develop a gel, incorporating an extract from Cliona Delitrix into the formulations. Obtained formulations were characterized by properties such as extensibility, adherence and mucoadhesive capacity. These formulations showed great physical stability under prevalent marine conditions both in vitro and in situ. In the same way was designed a device that let the smearing of the gel over the coral surfaces carried

  7. COMPARATIVE STUDY OF CLINICAL EFFICACY AND SIDE EFFECTS OF ADAPALENE 0.1% GEL AND BENZOYL PEROXIDE 2.5% GEL AS MONOTHERAPIES AND COMBINATION THERAPY IN FACIAL ACNE: INDIAN PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Adarsh

    2014-04-01

    Full Text Available A fixed dose combination gel with adapalene 0.1% and benzoyl peroxide 2.5% has been developed for the once daily treatment of acne vulgaris .This fixed combination was approved by U.S FDA in December 2008. This study was done in the Department of Dermatology, KIMS, Bangalore to assess the efficacy and adverse effects of topical adapalene 0.1%–benzoyl peroxide 2.5% combination gel as compared to topical adapalene 0.1% gel and 2.5% benzoyl peroxide gel (monotherapies in the treatment of facial acne vulgaris. To the best of our knowledge, this is one of the few studies conducted in India. It was an open label study. Participants received either adapalene 0.1% gel, benzoyl peroxide 2.5% gel or adapalene 0.1% – benzoyl peroxide 2.5% combination gel for 12 weeks. Follow up was done at the end of 1,2,4,8 and 12 weeks. Evaluation included lesion count and adverse events. Participants included males and females aged between 18-38 years with grade 2 or 3 facial acne vulgaris as per investigators global assessment of acne scale. A total of 62 participants were recruited out of which 23 were males and 39 were females.88.71% participants completed the study. The study revealed that combination of adapalene 0.1% and benzoyl peroxide 2.5% gel was more effective in the treatment of facial acne as compared to adapalene 0.1% gel and benzoyl peroxide 2.5% gel (topical monotherapies. The safety of combination of adapalene 0.1% and benzoyl peroxide 2.5% gel was comparable with adapalene 0.1% gel and benzoyl peroxide 2.5% gel monotherapies.

  8. Development of water-repellent organic–inorganic hybrid sol–gel coatings on aluminum using short chain perfluoro polymer emulsion

    Energy Technology Data Exchange (ETDEWEB)

    Wankhede, Ruchi Grover, E-mail: 123.ruchi@gmail.com [IITB-Monash Research Academy, Mumbai 400076 (India); Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076 (India); Morey, Shantaram [Dow Chemicals (India); Khanna, A.S. [Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076 (India); Birbilis, N. [Department of Materials Engineering, Monash University, Victoria 3800 (Australia)

    2013-10-15

    The development of an organic–inorganic sol–gel coating system (thickness ∼ 2 μm) on aluminum is reported. The coating uses glycidoxytrimethoxysilane (GPTMS) and methyltrimethoxysilane (MTMS) as silane precursors, crosslinked with hexamethylmethoxymelamine (HMMM) and followed by hydrophobic modification using a water base short chain per-fluoro emulsion (FE). Such coating resulted in enhanced hydrophobicity with a contact angle of about 120° and sliding angle of 25° for a 20 μL water droplet. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements showed reduced corrosion upon coated substrates than the bare; correlated with both a higher degree of water repellency and formation of low permeable crosslinked sol–gel network. The structure of the coatings deposited was analyzed using Fourier transform infrared (FTIR) and X-ray photoelectron (XPS) spectroscopy, revealing replacement of hydrophillic surface hydroxyls groups with low energy per-fluoro groups.

  9. Cyclization Phenomena in the Sol-Gel Polymerization of a,w-Bis(triethoxysilyl)alkanes and Incorporation of the Cyclic Structures into Network Silsesquioxane Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Alam, T.M.; Carpenter, J.P.; Dorhout, P.K.; Greaves, J.; Loy, D.A.; Shaltout, R.; Shea, K.J.; Small, J.H.

    1999-01-04

    Intramolecular cyclizations during acid-catalyzed, sol-gel polymerizations of ct,co- bis(tietioxysilyl)aWmes substintidly lengtien gelties formonomers witietiylene- (l), propylene- (2), and butylene-(3)-bridging groups. These cyclizations reactions were found, using mass spectrometry and %i NMR spectroscopy, to lead preferentially to monomeric and dimeric products based on six and seven membered disilsesquioxane rings. 1,2- Bis(triethoxysilyl)ethane (1) reacts under acidic conditions to give a bicyclic drier (5) that is composed of two annelated seven membered rings. Under the same conditions, 1,3- bis(triethoxysilyl)propane (2), 1,4-bis(triethoxysilyl)butane (3), and z-1,4- bis(triethoxysilyl)but-2-ene (10) undergo an intramolecular condensation reaction to give the six membemd and seven membered cyclic disilsesquioxanes 6, 7, and 11. Subsequently, these cyclic monomers slowly react to form the tricyclic dirners 8,9 and 12. With NaOH as polymerization catalyst these cyclic silsesquioxanes readily ~aeted to afford gels that were shown by CP MAS z%i NMR and infr=d spectroscopes to retain some cyclic structures. Comparison of the porosity and microstructwe of xerogels prepared from the cyclic monomers 6 and 7 with gels prepared directly from their acyclic precursors 2 and 3, indicate that the final pore structure of the xerogels is markedly dependent on the nature of the precursor. In addition, despite the fact that the monomeric cyclic disilsesquioxane species can not be isolated from 1-3 under basic conditions due to their rapid rate of gelation, spectroscopic techniques also detected the presence of the cyclic structures in the resulting polymeric gels.

  10. Preparation and properties of PEO/LiClO4/KH560-SiO2 composite polymer electrolyte by sol-gel composite-in-situ method

    Institute of Scientific and Technical Information of China (English)

    PAN Chun-yue; GAO Jin-huan; ZHANG Qian; FENG Qing; CHAO meng

    2008-01-01

    Composite polymer electrolytes based on polyethylene oxide (PEO) were prepared by using LiClO4 as doping salt and silane-modified SiO2 as filler. SiO2 was formed in-situ in (PEO)8LiClO4 matrix by the hydrolysis and condensation reaction of Si(OC4H9)4. The crystallinity, morphology and ionic conductivity of composite polymer electrolyte films were examined by differential scanning calorimetry, scanning electron microscopy, atom force microscopy and alternating current impedance spectroscopy, respectively. Compared with the crystallinity of the unmodified SiO2 as inert filler, that of composite polymer electrolytes is decreased. The results show that silane-modified SiO2 particles are uniformly dispersed in (PEO)8LiClO4 composite polymer electrolyte film and the addition of silane-modified SiO2 increases the ionic conductivity of the (PEO)8LiClO4 more noticeably. When the mass fraction of SiO2 is about 10%, the conductivity of (PEO)8LiClO4-modified SiO2 attains a maximum value of 4.8×10-5S·cm-1.

  11. A randomized, placebo-controlled, single-blinded, split-faced clinical trial evaluating the efficacy and safety of KLOX-001 gel formulation with KLOX light-emitting diode light on facial rejuvenation

    Science.gov (United States)

    Nikolis, Andreas; Bernstein, Steven; Kinney, Brian; Scuderi, Nicolo; Rastogi, Shipra; Sampalis, John S

    2016-01-01

    Purpose Many treatment modalities exist to counteract the effects of cutaneous aging. Ablative methods have been the mainstay for nonsurgical facial rejuvenation. In recent years, nonablative techniques have been developed with the aim of achieving facial rejuvenation without epidermal damage. Light-emitting diode (LED) photorejuvenation is a novel nonablative technique that induces collagen synthesis through biophotomodulatory pathways. Materials and methods A single-center, randomized, single-blinded, placebo-controlled, split-faced clinical trial was designed. Thirty-two patients were enrolled for a 12-week study. Patients were randomized into one of four groups: Group A, treatment with KLOX-001 gel formulation and white LED (placebo) light; Group B, treatment with a placebo/base gel (no active chromophore) formulation and KLOX LED light; Group C, treatment with KLOX-001 gel formulation and KLOX LED light; and Group D, treatment with the standard skin rejuvenating treatment (0.1% retinol-based cream). Patients received treatment at weeks 0, 1, 2, and 3, and returned to the clinic at weeks 4, 8, and 12 for clinical assessments performed by an independent, blinded committee of physicians using subjective clinician assessment scales. Tolerability, adverse outcomes, and patient satisfaction were also assessed. Results Analysis demonstrated that the KLOX LED light with KLOX placebo/base gel and the KLOX LED light + KLOX-001 gel formulation groups were superior to standard of care and KLOX-001 gel formulation with placebo light on subjective clinical assessment and multiple wrinkle scales, with statistically significant results obtained for brow positioning, perioral wrinkling, and total wrinkle score. Conclusion The study results show that KLOX LED light with KLOX-001 gel formulation and KLOX LED light with KLOX placebo/base gel are effective, safe, well-tolerated, and painless treatment modalities for skin rejuvenation. PMID:27257391

  12. Monomer consumption in MAGIC-type polymer gels in the Bragg-peak of proton beams observed by volume selective 1H MR-spectroscopy (MRS): proof of principle for high resolution MRS-methodology with a sensitive rf-detector

    International Nuclear Information System (INIS)

    Mono-energetic proton and heavy ion beams for tumour therapy feature high dose gradients laterally and at its penetration depth, characterized by the Bragg-peak. The 3-dimensional dosimetry of such Hadron particle beams poses high demands on the spatial resolution of the imaging methodology and linearity of the polymer gel dose response in a wide dose range and at high linear energy transfer (LET). In almost all polymer gels the Bragg-peak dose response is therefore quenched. Volume selective MR-spectroscopy is in principle capable of delivering information on the polymerization process. We here present the MR-methodology to obtain MR-spectroscopic (MRS) data on the monomer consumption at the very small voxel volumes necessary for resolving e.g. the Bragg-peak area. Using additional hardware components, i.e. a strong gradient system and a very sensitive rf-detector at a high field human 7T scanner, MR-microimaging and MRS with 600 μm depth resolution can be implemented at very short measurement time. The vinyl groups of methacrylic acid in a MAGIC-type polymer gel can be resolved by volume selective MRS. The complete monomer consumption in the Bragg-peak due to polymerization is demonstrated selectively in the Bragg-peak indicating one main reason for Bragg-peak quenching in the investigated polymer gel.

  13. Effects of TiO2 and TiC Nanofillers on the Performance of Dye Sensitized Solar Cells Based on the Polymer Gel Electrolyte of a Cobalt Redox System.

    Science.gov (United States)

    Venkatesan, Shanmuganathan; Liu, I-Ping; Chen, Li-Tung; Hou, Yi-Chen; Li, Chiao-Wei; Lee, Yuh-Lang

    2016-09-21

    Polymer gel electrolytes (PGEs) of cobalt redox system are prepared for dye sensitized solar cell (DSSC) applications. Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) is used as a gelator of an acetonitrile (ACN) liquid electrolyte containing tris(2,2'-bipyridine)cobalt(II/III) redox couple. Titanium dioxide (TiO2) and titanium carbide (TiC) nanoparticles are utilized as nanofillers (NFs) of this PGE, and the effects of the two NFs on the conductivity of the PGEs, charge-transfer resistances at the electrode/PGE interface, and the performance of the gel-state DSSCs are studied and compared. The results show that the presence of TiC NFs significantly increases the conductivity of the PGE and decreases the charge-transfer resistance at the Pt counter-electrode (CE)/PGE interface. Therefore, the gel-state DSSC utilizing TiC NFs can achieve a conversion efficiency (6.29%) comparable to its liquid counterpart (6.30%), and, furthermore, the cell efficiency can retain 94% of its initial value after a 1000 h stability test at 50 °C. On the contrary, introduction of TiO2 NFs in the PGE causes a decrease of cell performances. It shows that the presence of TiO2 NFs increases the charge-transfer resistance at the Pt CE/PGE interface, induces the charge recombination at the photoanode/PGE interface, and, furthermore, causes a dye desorption in a long-term-stability test. These results are different from those reported for the iodide redox system and are ascribed to a specific attractive interaction between TiO2 and cobalt redox ions.

  14. Aloe vera phenomenon: a review of the properties and modern uses of the leaf parenchyma gel

    Energy Technology Data Exchange (ETDEWEB)

    Grindlay, D.; Reynolds, T.

    1986-06-01

    The mucilaginous gel from the parenchymatous cells in the leaf pulp of Aloe vera has been used since early times for a host of curative purposes. This gel should be distinguished clearly from the bitter yellow exudate originating from the bundle sheath cells, which is used for its purgative effects. Aloe vera gel has come to play a prominent role as a contemporary folk remedy, and numerous optimistic, and in some cases extravagant, claims have been made for its medicinal properties. Modern clinical use of the gel began in the 1930s, with reports of successful treatment of X-ray and radium burns, which led to further experimental studies using laboratory animals in the following decades. The reports of these experiments and the numerous favourable case histories did not give conclusive evidence, since although positive results were usually described, much of the work suffered from poor experimental design and insufficiently large test samples. In addition some conflicting or inconsistent results were obtained. With the recent resurgence of interest in Aloe vera gel, however, new experimental work has indicated the possibility of distinct physiological effects. Chemical analysis has shown the gel to contain various carbohydrate polymers, notably either glucomannans or pectic acid, along with a range of other organic and inorganic components. Although many physiological properties of the gel have been described, there is no certain correlation between these and the identified gel components. 154 references.

  15. The gel generator project: the prospectus of a development program in which the gel generator is assessed as a suitable source of technetium-99m in clinical nuclear medicine

    International Nuclear Information System (INIS)

    An overview is presented of the gel generator project based on the neutron activation of molybdenum. It operates through the simple technique of column elution, and the separated Tc-99m is not contaminated with undesirable radioactive or chemical impurities. The principles behind technetium generators are discussed, and publications and patents applying to the gel generator are listed

  16. Molecularly imprinted polymer-sol-gel tablet toward micro-solid phase extraction: I. Determination of methadone in human plasma utilizing liquid chromatography-tandem mass spectrometry.

    Science.gov (United States)

    El-Beqqali, Aziza; Abdel-Rehim, Mohamed

    2016-09-14

    In the present work molecularly imprinted sol-gel tablet (MIP-Tablet) was prepared. The MIP-sol-gel was prepared as a thin layer on polyethylene material in a tablet form. Methadone-d9 was selected as the template and 3-(propylmethacrylate)-trimethoxysilane was used as precursor. MIP-Tablet was applied for micro-solid phase extraction (μ-SPE). The MIP-Tablet was used for the determination of methadone in human plasma samples utilizing liquid chromatography-tandem mass spectrometry; and each tablet could be used twenty times. The extraction time was 10 min while desorption time was 6 min. Factors affecting the extraction efficiency such as desorption solvents, sample pH, salt addition, extraction time, desorption time and adsorption capacity were investigated. The calibration curves were obtained within the range of 5-5000 ng/mL using methadone in human plasma samples. The coefficients of determination (r(2)) values were ≥0.999 for all runs and the extraction recovery was >80%. The accuracy values for quality control samples varied from +3.6 to +9.7% and the inter-day precision (RSD %) values were ranged from 5.0 to 8.0%. The limit of detection was 1.0 ng/mL and the lower limit of quantification was 5 ng/mL utilizing methadone in human plasma samples. PMID:27566346

  17. Gel fire suppressants for controlling underground heating

    Institute of Scientific and Technical Information of China (English)

    HU Sheng-gen; XUE Sheng

    2011-01-01

    One of the major safety issues in coal mining is heatings and the resultant spontaneous combustion in underground coal mines.CSIRO researchers have developed a number of polymer gels suitable for controlling heatings in coal mines.These gels were developed to meet strict selection criteria including easy preparation,no or low toxicity,controllable gelation time,adaptable to mine water chemistry,adjustable viscosity,relatively long gel life,thermally and chemically stable and low cost.The HPAM-Aluminum Citrate gel system was identified to be the most favourable gel system for fire suppression in underground coal mines.These gels can be applied to the areas undergoing coal heating or gas leakage at a controllable gelation time and impermeable gel barriers can be formed in the areas to block ingress of air.

  18. Rheology of Biopolymer Solutions and Gels

    Directory of Open Access Journals (Sweden)

    David R. Picout

    2003-01-01

    Full Text Available Rheological techniques and methods have been employed for many decades in the characterization of polymers. Originally developed and used on synthetic polymers, rheology has then found much interest in the field of natural (bio polymers. This review concentrates on introducing the fundamentals of rheology and on discussing the rheological aspects and properties of the two major classes of biopolymers: polysaccharides and proteins. An overview of both their solution properties (dilute to semi-dilute and gel properties is described.

  19. Enzymatically crosslinked carboxymethyl-chitosan/gelatin/nano-hydroxyapatite injectable gels for in situ bone tissue engineering application

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, Debasish; Bhunia, Bibhas; Banerjee, Indranil [Department of Biotechnology, Indian Institute of Technology Kharagpur (India); Datta, Pallab; Dhara, Santanu [School of Medical Science and Technology, Indian Institute of Technology Kharagpur (India); Maiti, Tapas K., E-mail: maititapask@gmail.com [Department of Biotechnology, Indian Institute of Technology Kharagpur (India)

    2011-10-10

    Present study reports synthesis and characterization of an enzymatically crosslinked injectable gel (iGel) suitable for cell based bone tissue engineering application. The gel comprises of carboxymethyl-chitosan (CMC)/gelatin/nano-hydroxyapatite (nHAp) susceptible to tyrosinase/p-cresol mediated in situ gelling at physiological temperature. Study revealed that a combination of tyrosinase (60U) and p-cresol (2 mM) as crosslinking agents yield rigid gels at physiological temperature when applied to CMC/gelatin within 35 min in presence or absence of nHAp. Rheological study in conjugation with FT-IR analysis showed that an increase in CMC concentration in the gel leads to higher degree of crosslinking and higher strength. Scanning electron microscopy showed that pore sizes of iGels increased with higher gelatin concentration. In vitro study of osteoblast cell proliferation and differentiation showed that, although all iGels are supportive towards the growth of primary osteoblast cells, GC1:1 supported cellular differentiation to the maximum. Application of iGels in mice revealed that stability of the in situ formed gels depends on the degree of crosslinking and CMC concentration. In conclusion, the iGels may be used in treating irregular small bone defects with minimal clinical invasion as well as for bone cell delivery. - Research Highlights: {yields} Enzymatically crosslinked injectable gel made up of CM-chitosan (C)/gelatin (G)/nHAp. {yields} Tyrosinase/p-cresol used for crosslinking and in situ gelling of polymers at 37deg. C. {yields} 60U tyrosinase and 2mM p-cresol is needed for gelation in 35 min. {yields} Higher GC ratio manifests lower crosslinking and gel strength but higher porosity. {yields} GC1:1 shows maximum in vivo gel stability and in vitro osteoblast differentiation.

  20. Enzymatically crosslinked carboxymethyl-chitosan/gelatin/nano-hydroxyapatite injectable gels for in situ bone tissue engineering application

    International Nuclear Information System (INIS)

    Present study reports synthesis and characterization of an enzymatically crosslinked injectable gel (iGel) suitable for cell based bone tissue engineering application. The gel comprises of carboxymethyl-chitosan (CMC)/gelatin/nano-hydroxyapatite (nHAp) susceptible to tyrosinase/p-cresol mediated in situ gelling at physiological temperature. Study revealed that a combination of tyrosinase (60U) and p-cresol (2 mM) as crosslinking agents yield rigid gels at physiological temperature when applied to CMC/gelatin within 35 min in presence or absence of nHAp. Rheological study in conjugation with FT-IR analysis showed that an increase in CMC concentration in the gel leads to higher degree of crosslinking and higher strength. Scanning electron microscopy showed that pore sizes of iGels increased with higher gelatin concentration. In vitro study of osteoblast cell proliferation and differentiation showed that, although all iGels are supportive towards the growth of primary osteoblast cells, GC1:1 supported cellular differentiation to the maximum. Application of iGels in mice revealed that stability of the in situ formed gels depends on the degree of crosslinking and CMC concentration. In conclusion, the iGels may be used in treating irregular small bone defects with minimal clinical invasion as well as for bone cell delivery. - Research Highlights: → Enzymatically crosslinked injectable gel made up of CM-chitosan (C)/gelatin (G)/nHAp. → Tyrosinase/p-cresol used for crosslinking and in situ gelling of polymers at 37deg. C. → 60U tyrosinase and 2mM p-cresol is needed for gelation in 35 min. → Higher GC ratio manifests lower crosslinking and gel strength but higher porosity. → GC1:1 shows maximum in vivo gel stability and in vitro osteoblast differentiation.

  1. Superabsorbing gel for actinide, lanthanide, and fission product decontamination

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, Michael D.; Mertz, Carol J.

    2016-06-07

    The present invention provides an aqueous gel composition for removing actinide ions, lanthanide ions, fission product ions, or a combination thereof from a porous surface contaminated therewith. The composition comprises a polymer mixture comprising a gel forming cross-linked polymer and a linear polymer. The linear polymer is present at a concentration that is less than the concentration of the cross-linked polymer. The polymer mixture is at least about 95% hydrated with an aqueous solution comprising about 0.1 to about 3 percent by weight (wt %) of a multi-dentate organic acid chelating agent, and about 0.02 to about 0.6 molar (M) carbonate salt, to form a gel. When applied to a porous surface contaminated with actinide ions, lanthanide ions, and/or other fission product ions, the aqueous gel absorbs contaminating ions from the surface.

  2. Development of Zingiber officinale in oral dissolving films: Effect of polymers on in vitro, in vivo parameters and clinical efficacy

    Directory of Open Access Journals (Sweden)

    Anwar S Daud

    2011-01-01

    Full Text Available Oral dissolving drug delivery system offers a solution for those patients having difficulty in swallowing tablets/capsules, etc. Zingiber officinale, has been used for medicinal purpose since antiquity to treat motion sickness, pregnancy, and cancer-chemotherapy-induced vomiting, mild stomach upset, cough, chronic bronchial problems, and low-grade infections of all kinds and anorexia condition. This work investigates the possibility of developing Zingiber officinale oral dissolving films allowing fast, reproducible dissolution in oral cavity; thus bypassing first pass metabolism. The oral dissolving films were prepared by solvent-casting method. Prepared films were evaluated for film-forming properties, physico-mechanical properties, palatability, microbial limit test, accelerated stability studies, and clinical efficacy test. The different polymers such as hydroxypropyl methylcellulose 5cps, maltodextrin, pullulan, and polyvinyl alcohol were explored individually and in combination with each other for the formation of film. Among all polymers, maltodextrin and HPMC 5 cps alone and in combination showed excellent film-forming properties as well as very good physico-mechanical properties. The films resulted into excellent palatability along with least disintegrating time. But at accelerated stability studies, only HPMC 5 cps was found to be stable when compared with other formulations. So, it was concluded that HPMC 5 cps is the best film forming as well as stable polymer with respect to Zingiber officinale oral dissolving film.

  3. Impact of biodegradable versus durable polymer drug-eluting stents on clinical outcomes in patients with coronary artery disease: a meta-analysis of 15 randomized trials

    Institute of Scientific and Technical Information of China (English)

    Zhang Yaojun; Tian Nailiang; Dong Shengjie; Ye Fei; Li Minghui; Christos V.Bourantas; Javaid Iqbal

    2014-01-01

    Background Drug eluting stents (DESs) made with biodegradable polymer have been developed in an attempt to improve clinical outcomes.However,the impact of biodegradable polymers on clinical events and stent thrombosis (ST) remains controversial.Methods We searched Medline,the Cochrane Library and other internet sources,without language or date restrictions for articles comparing clinical outcomes between biodegradable polymer DES and durable polymer DES.Safety endpoints were ST (definite,definite/probable),mortality,and myocardial infarction (MI).Efficacy endpoints were major adverse cardiac event (MACE) and target lesion revascularization (TLR).Results We identified 15 randomized controlled trials (n=17 068) with a weighted mean follow-up of 20.6 months.There was no statistical difference in the incidence of definite/probable ST between durable polymer-and biodegradable polymerDES; relative risk (RR) 0.83; 95% confidence interval (CI) 0.62-1.11; P=0.22.Biodegradable polymer DES had similar rates of definite ST (RR 0.94,95% CI 0.66-1.33,P=0.72),mortality (RR 0.94,95% C/0.82-1.09,P=0.43),MI (RR 1.08,95% CI 0.92-1.26.P=0.35),MACE (RR 0.99,95% CI 0.91-1.09,P=0.85),and TLR (RR,0.94,95% CI 0.83-1.06,P=0.30) compared with durable polymer DES.Based on the stratified analysis of the included trials,the treatment effect on definite ST was different at different follow-up times:≤1 year favoring durable polymer DES and >1 year favoring biodegradable polymer DES.Conclusions Biodegradable polymer DES has similar safety and efficacy for treating patients with coronary artery disease compared with durable polymer DES.Further data with longer term follow-up are warranted to confirm the potential benefits of biodegradable polymer DES.

  4. Effect of the alkaline cation size on the conductivity in gel polymer electrolytes and their influence on photo electrochemical solar cells.

    Science.gov (United States)

    Bandara, T M W J; Fernando, H D N S; Furlani, M; Albinsson, I; Dissanayake, M A K L; Ratnasekera, J L; Mellander, B-E

    2016-04-28

    The nature and concentration of cationic species in the electrolyte exert a profound influence on the efficiency of nanocrystalline dye-sensitized solar cells (DSSCs). A series of DSSCs based on gel electrolytes containing five alkali iodide salts (LiI, NaI, KI, RbI and CsI) and polyacrylonitrile with plasticizers were fabricated and studied, in order to investigate the dependence of solar cell performance on the cation size. The ionic conductivity of electrolytes with relatively large cations, K(+), Rb(+) and Cs(+), was higher and essentially constant, while for the electrolytes containing the two smaller cations, Na(+) and Li(+), the conductivity values were lower. The temperature dependence of conductivity in this series appears to follow the Vogel-Tamman-Fulcher equation. The sample containing the smallest cation shows the lowest conductivity and the highest activation energy of ∼36.5 meV, while K(+), Rb(+) and Cs(+) containing samples show an activation energy of ∼30.5 meV. DSSCs based on the gel electrolyte and a TiO2 double layer with the N719 dye exhibited an enhancement in the open circuit voltage with increasing cation size. This can be attributed to the decrease in the recombination rate of electrons and to the conduction band shift resulting from cation adsorption by TiO2. The maximum efficiency value, 3.48%, was obtained for the CsI containing cell. The efficiencies shown in this study are lower compared to values reported in the literature, and this can be attributed to the use of a single salt and the absence of other additives, since the focus of the present study was to analyze the cation effect. The highest short circuit current density of 9.43 mA cm(-2) was shown by the RbI containing cell. The enhancement of the solar cell performance with increasing size of the cation is discussed in terms of the effect of the cations on the TiO2 anode and ion transport in the electrolyte. In liquid electrolyte based DSSCs, the short circuit current density

  5. The clinical application of silicon gel breast prosthesis breast augmentation%硅凝胶乳房假体隆乳的临床应用体会

    Institute of Scientific and Technical Information of China (English)

    刘为廷; 宋建星; 寇静波; 乔静

    2013-01-01

    目的:探讨硅凝胶乳房假体置入隆乳术的临床疗效.方法:依据测量胸乳距、乳房基底宽度、乳头至乳房下皱襞距离等数据确定选用的假体类型、容量;采用腋窝切口或乳晕切口,将假体置于胸大肌深面或浅面.结果:统计我科自2010年5月至2011年12月采用国产硅凝胶毛面假体隆乳术122例,其中置于胸大肌深面68例、置于浅面54例,术后随访3个月至1年,所有患者乳房外形逼真,手感真实柔软,出现轻度包膜挛缩1例,未见感染、血肿及假体扭曲等并发症.结论:硅凝胶乳房假体与身体组织相容性好,适当的手术方法及术后处理可明显降低包膜挛缩率.%Objective To discuss the clinical effect of augmentation mammoplasty with silica gel breast prosthesis. Methods Firstly.the prosthesis was chosen according to some measured data such as the breast width, the basal breast width, the distance of the nipple to the crease under the breast fold. Then the prosthesis was put into the deep surface or superfical surface of the major pectoralis muscle. Results We have 122 cases (68 cases for deep surface and 54 cases for superfical surface) of augmentation mammoplasty with rough surface prothesis made of domestic silicone gel from May 2010 to December 2011. Three month to one year postoperative follow-up show that the shape and the touch of breasts of all patients are close to real. Mild capsular contracture happened in 1 case, but none complications such as infection,hematoma and prothesis distortion. Conclusions The tissue compatibility of silicone gel breast prosthesis to body is good. The incidence rate of capsular contracture can be reduced by suitable operation method and postoperative treatment.

  6. Preparation and application of the sol-gel-derived acrylate/silicone co-polymer coatings for headspace solid-phase microextraction of 2-chloroethyl ethyl sulfide in soil.

    Science.gov (United States)

    Liu, Mingming; Zeng, Zhaorui; Fang, Huaifang

    2005-05-27

    Three types of novel acrylate/silicone co-polymer coatings, including co-poly(methyl acrylate/hydroxy-terminated silicone oil) (MA/OH-TSO), co-poly(methyl methacrylate/OH-TSO) (MMA/OH-TSO) and co-poly(butyl methacrylate/OH-TSO) (BMA/OH-TSO), were prepared for the first time by sol-gel method and cross-linking technology and subsequently applied to headspace solid-phase microextraction (HS-SPME) of 2-chloroethyl ethyl sulfide (CEES), a surrogate of mustard, in soil. The underlying mechanisms of the coating process were discussed and confirmed by IR spectra. The selectivity of the three types of sol-gel-derived acrylate/silicone coated fibers was studied, and the BMA/OH-TSO coated fibers exhibited the highest extraction ability to CEES. The concentration of BMA and OH-TSO in sol solution was optimized, and the BMA/OH-TSO (3:1)-coated fibers possessed the highest extraction efficiency. Compared with commercially available polyacrylate (PA) fiber, the sol-gel-derived BMA/OH-TSO (3:1) fibers showed much higher extraction efficiency to CEES. Therefore, the BMA/OH-TSO (3:1)-coated fibers were chosen for the analysis of CEES in soil matrix. The reproducibility of coating preparation was satisfactory, with the RSD 2.39% within batch and 3.52% between batches, respectively. The coatings proved to be quite stable at high temperature (to 350 degrees C) and in different solvents (organic or inorganic), thus their lifetimes (to 150 times) are longer than conventional fibers. Extraction parameters, such as the volume of water added to the soil, extraction temperature and time, and the ionic strength were optimized. The linearity was from 0.1 to 10 microg/g, the limit of detection (LOD) was 2.7 ng/g, and the RSD was 2.19%. The recovery of CEES was 88.06% in agriculture soil, 92.61% in red clay, and 101.95% in sandy soil, respectively.

  7. 假体隆臀术:21例临床报告%Gluteal augmentation with silicone gel implant: clinical report on 21 cases

    Institute of Scientific and Technical Information of China (English)

    田方文; 陈光平; 徐荣阳; 邓正军; 徐斌; 赵正杰; 段家海; 张少军

    2013-01-01

    目的 探讨应用毛面圆形乳房假体隆臀的可行性及临床效果.方法 自2008年4月至2011年7月,对21例求美者采用Mentor圆形毛面硅凝胶假体行假体隆臀,于臀间沟处做手术切口,切开皮肤、皮下组织,将臀大肌起点处切开,分离出臀大肌下间隙并置入假体.结果 术后随访6~17个月,本组21例求美者伤口均Ⅰ期愈合,臀部外观挺拔,效果满意.无血肿、感染、臀部疼痛感、假体破裂等并发症发生.结论 应用毛面圆形乳房假体行隆臀术,术式安全、有效,效果满意.%Objective To explore the feasibility and clinical outcome of the application of gluteal augmentation with silicone gel prothesis. Methods In this study, totally 21 patients received gluteal augmentation surgeries with Mentor obscured circular prosthesis implant from April 2008 to September 2011. A hidden incision along coccyx groove was designed for the operation. From the incision, gluteus maximus was released from its origin for preparing the muscle plane for prosthesis implant.Results After 6 to 17 months follow-up, all 21 cases healed primarily with attractive buttock outcome. Satisfactory results were received without hematoma, infection, pain or prosthesis rupture occurred. Conclusion It is a safe and effective approach of gluteal augmentation with silicone gel prosthesis implant for buttock reshaping.

  8. Polyclonal infections due to Mycobacterium avium complex in patients with AIDS detected by pulsed-field gel electrophoresis of sequential clinical isolates.

    Science.gov (United States)

    Slutsky, A M; Arbeit, R D; Barber, T W; Rich, J; von Reyn, C F; Pieciak, W; Barlow, M A; Maslow, J N

    1994-01-01

    Invasive infection with organisms of the Mycobacterium avium complex (MAC) is common among patients with advanced human immunodeficiency virus infection. In previous studies, we analyzed multiple individual colonies of MAC isolated from specimens obtained at the same time and observed that 14 to 20% of patients are simultaneously infected with more than one strain. In this study, we examined sequential isolates from 12 patients with AIDS who had two or more MAC isolates available from clinical specimens collected more than 1 week apart; the intervals between the first and last specimens ranged from 8 to 192 (median, 46) days. For each isolate, restriction digests of genomic DNA were analyzed by pulsed-field gel electrophoresis; DNA was prepared by using a protocol, described here in detail, which had been optimized for conditions of bacterial growth and lysis. The pulsed-field gel electrophoresis analysis identified four patients (33%) infected with two different MAC strains. Both M. avium and M. intracellulare were cultured from blood specimens from two patients. In each of the four patients, the second strain was identified from a culture taken within 14 days of the initial study isolate, and in three of these patients, the first strain was detected again in a subsequent culture. These observations suggest that the presence of two different strains among isolates from sequential cultures may reflect ongoing polyclonal infection. We conclude that polyclonal infection with MAC is common among patients with AIDS. The identification of such infections may be critical in the development of effective treatments. Images PMID:7929773

  9. Characteristics of polyacrylamide gel with THPC and Turnbull Blue gel dosimeters evaluated using optical tomography

    International Nuclear Information System (INIS)

    The purpose of this study was to compare characteristics of radiochromic gel – Turnbull Blue gel (TB gel) with polymer gel – polyacrylamide gel and tetrakis hydroxymethyl phosphonium chloride (PAGAT) using optical tomography. Both types of gels were examined in terms of dose sensitivity, dose response linearity and background value of spectrophotometric absorbance. The calibration curve was obtained for 60Co irradiation performed on Gammacell 220 at predefined gamma dose levels between 0 and 140 Gy for TBG and 0–15 Gy for PAGAT. To measure relative dose distributions from stereotactic irradiation, dosimeters were irradiated on Leksell Gamma Knife Perfexion. The cylindrical glass housings filled with gel were attached to the stereotactic frame. They were exposed with single shot and 16 mm collimator by 65 Gy to a 50% prescription isodose for TB gel and 4 Gy to a 50% prescription isodose for PAGAT. Evaluations of dosimeters were performed on an UV–vis Spectrophotometer Helios β and an optical cone beam homemade tomography scanner with a 16-bit astronomy CCD camera with a set of color filters. The advantages and potential disadvantages for both types of gel dosimeters were summarized. Dose distribution in central slice and measured profiles of 16 mm shot shows excellent correspondence with treatment planning system Leksell GammaPlan® for both PAGAT and Turnbull Blue gels. - highlights: • Gel dosimeters are suitable for steep dose gradient verification. • An optical tomography evaluation method is successful. • Dose response characteristics of TB gel and PAGAT gel are presented

  10. Characteristics of polyacrylamide gel with THPC and Turnbull Blue gel dosimeters evaluated using optical tomography

    Science.gov (United States)

    Pilařová (Vávrů), Kateřina; Kozubíková, Petra; Šolc, Jaroslav; Spěváček, Václav

    2014-11-01

    The purpose of this study was to compare characteristics of radiochromic gel - Turnbull Blue gel (TB gel) with polymer gel - polyacrylamide gel and tetrakis hydroxymethyl phosphonium chloride (PAGAT) using optical tomography. Both types of gels were examined in terms of dose sensitivity, dose response linearity and background value of spectrophotometric absorbance. The calibration curve was obtained for 60Co irradiation performed on Gammacell 220 at predefined gamma dose levels between 0 and 140 Gy for TBG and 0-15 Gy for PAGAT. To measure relative dose distributions from stereotactic irradiation, dosimeters were irradiated on Leksell Gamma Knife Perfexion. The cylindrical glass housings filled with gel were attached to the stereotactic frame. They were exposed with single shot and 16 mm collimator by 65 Gy to a 50% prescription isodose for TB gel and 4 Gy to a 50% prescription isodose for PAGAT. Evaluations of dosimeters were performed on an UV-vis Spectrophotometer Helios β and an optical cone beam homemade tomography scanner with a 16-bit astronomy CCD camera with a set of color filters. The advantages and potential disadvantages for both types of gel dosimeters were summarized. Dose distribution in central slice and measured profiles of 16 mm shot shows excellent correspondence with treatment planning system Leksell GammaPlan® for both PAGAT and Turnbull Blue gels. Gel dosimeters are suitable for steep dose gradient verification. An optical tomography evaluation method is successful. Dose response characteristics of TB gel and PAGAT gel are presented.

  11. Active Gel Model of Amoeboid Cell Motility

    CERN Document Server

    Callan-Jones, A C

    2013-01-01

    We develop a model of amoeboid cell motility based on active gel theory. Modeling the motile apparatus of a eukaryotic cell as a confined layer of finite length of poroelastic active gel permeated by a solvent, we first show that, due to active stress and gel turnover, an initially static and homogeneous layer can undergo a contractile-type instability to a polarized moving state in which the rear is enriched in gel polymer. This agrees qualitatively with motile cells containing an actomyosin-rich uropod at their rear. We find that the gel layer settles into a steadily moving, inhomogeneous state at long times, sustained by a balance between contractility and filament turnover. In addition, our model predicts an optimal value of the gel-susbstrate adhesion leading to maximum layer speed, in agreement with cell motility assays. The model may be relevant to motility of cells translocating in complex, confining environments that can be mimicked experimentally by cell migration through microchannels.

  12. Preparation of monolithic molecularly imprinted polymer sol-gel packed tips for high-throughput bioanalysis: extraction and quantification of L-tyrosine in human plasma and urine samples utilizing liquid chromatography and tandem mass spectrometry.

    Science.gov (United States)

    Moein, Mohammad Mahdi; El-Beqqali, Aziza; Abdel-Rehim, Abbi; Jeppsson-Dadoun, Amin; Abdel-Rehim, Mohamed

    2014-09-15

    In situ monolithic molecularly imprinted polymer sol-gel packed tips (MMSTs) were prepared and evaluated for the extraction of lung cancer biomarker L-tyrosine (Tyr) from human plasma and urine samples. Several extraction parameters such as the conditioning, washing and elution solutions, pH and time were investigated. The enrichment factor (EF) and extraction recovery (ER) were studied. MMST showed good selectivity and a high extraction recovery, and MMST as a sorbent showed good stability and repeatability. The method validation showed good regression correlation coefficients for plasma and urine samples (R(2)≥0.996) within the concentration range of 5-1000 and 1-1000 nmol L(-1) in plasma and urine samples, respectively. The lower limits of quantification (LLOQ) in the plasma and urine samples were 5 and 1 nmol L(-1), respectively. The between-batch precision for Tyr in plasma ranged from 1.0 to 6.0%, and in urine it was from 1.0 to 7.0%. The results show that the developed method has more facility, stability, durability and repeatability compared with previous similar methods. To the best of our knowledge, this is the first study aimed at the selective separation of Tyr as a lung cancer biomarker by MMSTs from biological matrixes and detection by LC/MS/MS. PMID:25108365

  13. Antibacterial Peptide-Based Gel for Prevention of Medical Implanted-Device Infection.

    Directory of Open Access Journals (Sweden)

    Mihaela Mateescu

    Full Text Available Implanted medical devices are prone to infection. Designing new strategies to reduce infection and implant rejection are an important challenge for modern medicine. To this end, in the last few years many hydrogels have been designed as matrices for antimicrobial molecules destined to fight frequent infection found in moist environments like the oral cavity. In this study, two types of original hydrogels containing the antimicrobial peptide Cateslytin have been designed. The first hydrogel is based on alginate modified with catechol moieties (AC gel. The choice of these catechol functional groups which derive from mussel's catechol originates from their strong adhesion properties on various surfaces. The second type of gel we tested is a mixture of alginate catechol and thiol-terminated Pluronic (AC/PlubisSH, a polymer derived from Pluronic, a well-known biocompatible polymer. This PlubisSH polymer has been chosen for its capacity to enhance the cohesion of the composition. These two gels offer new clinical uses, as they can be injected and jellify in a few minutes. Moreover, we show these gels strongly adhere to implant surfaces and gingiva. Once gelled, they demonstrate a high level of rheological properties and stability. In particular, the dissipative energy of the (AC/PlubisSH gel detachment reaches a high value on gingiva (10 J.m-2 and on titanium alloys (4 J.m-2, conferring a strong mechanical barrier. Moreover, the Cateslytin peptide in hydrogels exhibited potent antimicrobial activities against P. gingivalis, where a strong inhibition of bacterial metabolic activity and viability was observed, indicating reduced virulence. Gel biocompatibility tests indicate no signs of toxicity. In conclusion, these new hydrogels could be ideal candidates in the prevention and/or management of periimplant diseases.

  14. A randomized, placebo-controlled, single-blinded, split-faced clinical trial evaluating the efficacy and safety of KLOX-001 gel formulation with KLOX light-emitting diode light on facial rejuvenation

    Directory of Open Access Journals (Sweden)

    Nikolis A

    2016-05-01

    Full Text Available Andreas Nikolis,1 Steven Bernstein,2 Brian Kinney,3 Nicolo Scuderi,4 Shipra Rastogi,5 John S Sampalis6 1Victoria Park, Plastic Surgery Section, Westmount, QC, Canada; 2Dermatology Department, University of Montreal Health Centre, Montreal, QC, Canada; 3Department of Plastic Surgery, USC School of Medicine, Beverley Hills, CA, USA; 4Department of Plastic and Reconstructive Surgery, La Sapienza, Rome, Italy; 5KLOX Technologies, Laval, 6JSS Medical Research, Montreal, QC, Canada Purpose: Many treatment modalities exist to counteract the effects of cutaneous aging. Ablative methods have been the mainstay for nonsurgical facial rejuvenation. In recent years, nonablative techniques have been developed with the aim of achieving facial rejuvenation without epidermal damage. Light-emitting diode (LED photorejuvenation is a novel nonablative technique that induces collagen synthesis through biophotomodulatory pathways. Materials and methods: A single-center, randomized, single-blinded, placebo-controlled, split-faced clinical trial was designed. Thirty-two patients were enrolled for a 12-week study. Patients were randomized into one of four groups: Group A, treatment with KLOX-001 gel formulation and white LED (placebo light; Group B, treatment with a placebo/base gel (no active chromophore formulation and KLOX LED light; Group C, treatment with KLOX-001 gel formulation and KLOX LED light; and Group D, treatment with the standard skin rejuvenating treatment (0.1% retinol-based cream. Patients received treatment at weeks 0, 1, 2, and 3, and returned to the clinic at weeks 4, 8, and 12 for clinical assessments performed by an independent, blinded committee of physicians using subjective clinician assessment scales. Tolerability, adverse outcomes, and patient satisfaction were also assessed. Results: Analysis demonstrated that the KLOX LED light with KLOX placebo/base gel and the KLOX LED light + KLOX-001 gel formulation groups were superior to standard of

  15. Food gels filled with emulsion droplets : linking large deformation properties to sensory perception

    NARCIS (Netherlands)

    Sala, G.

    2007-01-01

    Key words: polymer gels, particle gels, emulsion, large deformation, friction, sensory

      This thesis reports studies on the large deformation and lubrication properties of emulsion-filled gels and the way these properties are related to the sensory perception of the gels. The des

  16. When do efficacy outcomes in clinical trials correlate with clinical relevance? analysis of clindamycin phosphate 1.2%-benzoyl peroxide 3.75% gel in moderate to severe acne vulgaris.

    Science.gov (United States)

    Del Rosso, James Q

    2016-07-01

    Acne vulgaris (AV) is a common skin disease that is challenging to successfully treat due to its complex underlying pathophysiology and chronicity. Unrealistic expectations based on the desire for rapid and complete clearance or local tolerability reactions related to topical medications often lead to incomplete adherence with therapy, premature treatment cessation, and poor therapeutic outcomes. Despite stressing to patients the importance of compliance and the lag time of several weeks before visible improvement may be noted with treatments for AV, data on evaluation of the time taken to achieve a clinically meaningful improvement of AV that may be perceived by clinicians and patients are limited. Clindamycin phosphate 1.2%-benzoyl peroxide 3.75% (clindamycin-BP 3.75%) gel has been shown in pivotal trials to be effective and well tolerated in patients with moderate to severe AV. This article reviews a new concept referred to as time to onset of action (TOA), which is described in detail and illustrated using the pivotal trial data with clindamycin-BP 3.75% gel for treatment of AV. PMID:27529706

  17. Genetic Diversity among Ciprofloxacin Resistant Enterococcus faecalis Isolated from Clinical Specimens with Pulsed-Field Gel Electrophoresis (PFGE Method

    Directory of Open Access Journals (Sweden)

    Moinian M

    2013-03-01

    Full Text Available Abstract Background and objective: Resistance to ciprofloxacin among Enterococcus faecalis (E.f isolates especially in UTI makes difficulties for treatment. In this study, the genetic diversity using PFGE method and detection of resistance genes including parC, gyrA , gyrB and parE among ciprofloxacin resistant E.f isolated from clinical specimens, are determined. Materials and methods: A total of 384 entreococcal isolates were collected from 6 hospitals and 3 private laboratories in Tehran and 50 ciprofloxacin resistant E.f isolates were obtained. Identification of species and resistance genes were done by PCR method. Antimicrobial and minimum inhibitory concentration (MICs tests were assayed with standard methods and finally genotyping was accomplished using PFGE method. Results: The range of ciprofloxacin MICs was 16 to 512 µg/ml. All of these isolates contained parC, 98 % gyrA , gyrB and 80 % parE genes. PFGE analysis, grouped 50 strains in 11 common types and 7 single types. The P4, P9 and P10 genotypes were shared between hospital and community isolates. Conclusion: According to these results the E.f isolates showed high clonal diversity. Because of the ciprofloxacin high MICs level among common pulsotypes we concluded that they have various distributions which may be due to highly transmission of resistant genes among enterococci. Indeed the colonized patients with these resistant isolates are reservoir for releasing of the resistant genes to community which requires more surveillance programs.

  18. Physicochemical behaviour of chitin gels.

    Science.gov (United States)

    Vachoud, L; Zydowicz, N; Domard, A

    2000-06-30

    Syneresis of chitin gels formed in the course of N-acetylation of chitosan in hydroalcoholic media has been studied. A critical cross-linking density related to a critical acetylation degree for which the gel undergoes weak syneresis and swells in water was shown (degree of acetylation (DA) 88%). Above this value, the weight loss during syneresis increases with DA. Conversely, syneresis decreases on increasing the polymer concentration, but disappears at a macroscopic level for a polymer concentration close to the critical concentration of entanglement in the initial solution. An increase in temperature favours the formation of hydrophobic interactions and new inter- and intramolecular hydrogen bondings. Due to the weak polyelectrolyte character of chitin, the weight of the gel depends on the pH and ionic strength of the media. Swelling-deswelling experiments show that the swelling of the gel is not fully reversible in relation with the formation of new cross-links during the depletion of the network. Our results reveals that the balance between segment-segment and segment-solvent interactions as well as the molecular mobility play the major role.

  19. Efficacy and safety of a nano-emulsion gel formulation of adapalene 0.1% and clindamycin 1% combination in acne vulgaris: A randomized, open label, active-controlled, multicentric, phase IV clinical trial

    Directory of Open Access Journals (Sweden)

    Siva Prasad

    2012-01-01

    Full Text Available Background: Acne vulgaris is a very common skin disease with a significant detrimental effect on the quality of life of the patients. Aims: To assess the comparative efficacy and safety of a nano-emulsion gel formulation of adapalene and clindamycin combination with its conventional formulation in the treatment of acne vulgaris of the face. It was a prospective, randomized, open label, active-controlled, multicentric, clinical trial. Methods: Eligible patients suffering from acne vulgaris of the face were randomized to receive once-daily treatment with a nano-emulsion gel or conventional gel formulation of adapalene 0.1% and clindamycin (as phosphate 1% combination for 12 weeks. Total, inflammatory and noninflammatory lesion counts, with grading of acne severity were carried out on a monthly basis. Safety assessments were done to determine the comparative local and systemic tolerability. Two-tailed significance testing was carried out with appropriate statistical tests, and P-values < 0.05 were considered as significant. Results: 209/212 patients enrolled in the study were eligible for efficacy and safety assessments in both nano-emulsion gel (118/119 patients and conventional gel (91/93 patients groups. Significantly better reductions in total (79.7% vs. 62.7%, inflammatory (88.7% vs. 71.4% and noninflammatory (74.9% vs. 58.4% lesions were reported with the nano-emulsion gel as compared to the conventional gel (P < 0.001 for all. Mean acne severity score also reduced significantly more with the nano-emulsion formulation (1.9 ± 0.9 vs. 1.4 ± 1.0; P < 0.001 than the comparator. Significantly lower incidence and lesser intensity of adverse events like local irritation (4.2% vs. 19.8%; P < 0.05 and erythema (0.8% vs. 9.9%; P < 0.05 were recorded with the nano-emulsion gel. Conclusions: The nano-emulsion gel formulation of adapalene and clindamycin combination appears to be more efficacious and better tolerated than the conventional formulation

  20. A comparison study of the clinical efficacy and safety of topical adapalene gel (0.1% and tretinoin cream (0.025% in the treatment of acne vulgaris

    Directory of Open Access Journals (Sweden)

    Usha Naraindas Khemani

    2016-06-01

    Conclusions: Adapalene gel 0.1% offers comparable efficacy to tretinoin cream 0.025 % cream , but is less irritating. Adapalene gel 0.1% is a safe and effective topical agent in the treatment of mild to moderate acne vulgaris in Indian patients. [Int J Basic Clin Pharmacol 2016; 5(3.000: 628-634

  1. Antimicrobial resistance, genotypic characterization and pulsed-field gel electrophoresis typing of extended spectrum β-lactamases-producing clinical Escherichia coli strains in Macao, China

    Institute of Scientific and Technical Information of China (English)

    YE Qian-hong; LAU Ying; LIANG Bin; TIAN Su-fei

    2011-01-01

    Background The rise of the production of CTX-M class extended spectrum β-lactamases (ESBLs) has been well documented in traveling countries but no data are found for Macao,an international travel city.The objectives of this study were to identify the antimicrobial resistance pattern,and determine the prevalence,genotype and clonal relationship of ESBLs in 209 clinical Escherichia coli strains from Macao,China.Methods Antimicrobial susceptibility test was performed to determine the resistance patterns of the isolates using the disk diffusion method with 17 antimicrobial agents.Phenotypic detection was screened and confirmed according to the Clinical and Laboratory Standards Institute.Genotypic characterization was detected by isoelectric focusing analysis,polymerase chain reaction and sequencing.The clonal relationship between the different ESBL isolates was studied by pulsed-field gel electrophoresis (PFGE).Results Imipenem and meropenem exhibited 100% susceptible among 209 strains.Overall,82.3%,67.3%,52.9%,51.2% and 51.0% of the isolates displayed resistance to ampicillin,tetracylcline,ciprofloxacin,sulfamethoxazole trimethoprin and gentamycin.The prevalence rate of ESBLs was 30.1%.Antibiotic resistances were found to be significantly higher among the ESBL producing group compared to non-ESBL producing group.We detected CTX-M-14 to be the major genotypic characterization of ESBLs (76.2%).Two strains showed indistinguishable patterns by PFGE.Conclusions The prevalence of antimicrobial resistance is alarming high in Macao.Antimicrobial resistance is significantly higher among the ESBL producing group.This study documented CTX-M-14 as the predominant ESBL type.Although indistinguishable pattern was found between two strains,it was too small to decide whether any of the investigated strains was epidemic.Our findings may be also pertinent for other geographic areas undergoing similar travel characteristics to understand the corresponding effects on bacterial

  2. Fluoride Rinses, Gels and Foams

    DEFF Research Database (Denmark)

    Twetman, Svante; Keller, Mette K

    2016-01-01

    AIM: The aim of this conference paper was to systematically review the quality of evidence and summarize the findings of clinical trials published after 2002 using fluoride mouth rinses, fluoride gels or foams for the prevention of dental caries. METHODS: Relevant papers were selected after...... (6 on fluoride mouth rinse, 10 on fluoride gel and 3 on fluoride foam); 6 had a low risk of bias while 2 had a moderate risk. All fluoride measures appeared to be beneficial in preventing crown caries and reversing root caries, but the quality of evidence was graded as low for fluoride mouth rinse......, moderate for fluoride gel and very low for acidulated fluoride foam. No conclusions could be drawn on the cost-effectiveness. CONCLUSIONS: This review, covering the recent decade, has further substantiated the evidence for a caries-preventive effect of fluoride mouth rinse, fluoride gel and foam...

  3. FORMULATION AND EVALUATION OF DENTAL GEL CONTAINING ESSENTIAL OIL OF CORIANDER AGAINST ORAL PATHOGENS

    Directory of Open Access Journals (Sweden)

    Pawar Vinita A

    2013-10-01

    Full Text Available The objective of this study was to investigate the antimicrobial potency of essential oil of Coriander against clinical samples isolated from the oral cavity of various patients and to formulate a suitable topical preparation containing Coriander oil. A total of 41 swabs were obtained from patients (age between 20 - 50 years which were diagnosed with oral infections like periodontal abscess, periapical abscess, chronic periodontities, periapical granuloma, dental caries, root caries and plaque samples. These samples were inoculated on Blood agar, Mac-conkeys agar and MRS Lactobacilli MRS agar, Mutans Sanguis agar, KF Streptococcal agar at 37°C for 24 – 48 h aerobically except for KF Streptococcal agar and Mutans Sanguis agar, which was incubated anaerobically at 37°C for 24 – 48 h. The isolates were identified by standard microbiological procedures. The samples had positive cultures of Streptococcus faecalis, Streptococcus sanguis, Streptococcus oralis, Streptococcus mutans, Streptococcus salivarius, Lactobacilli, CONS. The susceptibility of these isolates was determined using agar disc diffusion method for zone of inhibition. The evaluation of antimicrobial potency was studied prior to gel formulation to compare the changes in activity after incorporation in polymer gel. The topical formulations were developed using different concentrations of polymers and evaluated for various physicochemical parameters like pH, color, clarity, viscosity, consistency, homogeneity, spread ability. The activity of oil was not much affected by incorporation in gel. The gel showed promising antimicrobial activity against the strains used for the study.

  4. STUDY ON ACRYLAMIDE-SODIUM ACRYLATE COPOLYMER GELS

    Institute of Scientific and Technical Information of China (English)

    ZHOU Maotang; LI Qian; XU Jiping

    1990-01-01

    Acrylamide-sodium acrylate copolymer hydrogels have been obtained by radiation techniques.Two different methods have been used to introduce -COONa groups into polymer chains of the gels: (1) by partial hydrolysis of acrylamide homopolymer gel; (2) by direct copolymerization and crosslinking of acrylamide and sodium acrylate in aqueous solutions. It was found that the gels obtained in different ways had different properties, the swelling character of the gels obtained by partial hydrolysis were more sensitive to pH of swelling aqueous media. In order to explain these differences,13 C-NMR techniques were used to investigate the sequence distribution of monomer units of both gels.

  5. Characterization of a clinical polymer-drug conjugate using multiscale modeling.

    Science.gov (United States)

    Peng, Lili X; Ivetac, Anthony; Chaudhari, Akshay S; Van, Sang; Zhao, Gang; Yu, Lei; Howell, Stephen B; McCammon, J Andrew; Gough, David A

    2010-11-01

    The molecular conformation of certain therapeutic agents has been shown to affect the ability to gain access to target cells, suggesting potential value in defining conformation of candidate molecules. This study explores how the shape and size of poly-γ-glutamyl-glutamate paclitaxel (PGG-PTX), an amphiphilic polymer-drug with potential chemotherapeutic applications, can be systematically controlled by varying hydrophobic and hydrophilic entities. Eighteen different formulations of PGG-PTX varying in three PTX loading fractions (f(PTX)) of 0.18, 0.24, and 0.37 and six spatial arrangements of PTX ('clusters', 'ends', 'even', 'middle', 'random', and 'side') were explored. Molecular dynamics (MD) simulations of all-atom (AA) models of PGG-PTX were run until a statistical equilibrium was reached at 100 ns and then continued as coarse-grained (CG) models until a statistical equilibrium was reached at an effective time of 800 ns. Circular dichroism spectroscopy was used to suggest initial modeling configurations. Results show that a PGG-PTX molecule has a strong tendency to form coil shapes, regardless of the PTX loading fraction and spatial PTX arrangement, although globular shapes exist at f(PTX) = 0.24. Also, less uniform PTX arrangements such as 'ends', 'middle', and 'side' produce coil geometries with more curvature. The prominence of coil shapes over globules suggests that PGG-PTX may confer a long circulation half-life and high propensity for accumulation to tumor endothelia. This multiscale modeling approach may be advantageous for the design of cancer therapeutic delivery systems. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 936-951, 2010.

  6. Drugs and Polymers for Delivery Systems in OA Joints: Clinical Needs and Opportunities

    Directory of Open Access Journals (Sweden)

    Maarten Janssen

    2014-03-01

    Full Text Available Osteoarthritis (OA is a big burden of disease worldwide and one of the most common causes of disability in the adult population. Currently applied therapies consist of physical therapy, oral medication, intra-articular injections, and surgical interventions, with the main goal being to reduce pain and improve function and quality of life. Intra-articular (IA administration of drugs has potential benefits in OA treatment because it minimizes systemic bioavailability and side effects associated with oral administration of drugs without compromising the therapeutic effect in the joint. However, IA drug residence time is short and there is a clinical need for a vehicle that is able to provide a sustained release long enough for IA therapy to fulfill its promise. This review summarizes the use of different polymeric systems and the incorporated drugs for IA drug delivery in the osteoarthritic joint with a primary focus on clinical needs and opportunities.

  7. Preparation and swelling behavior of polyvinyl alcohol physiological saline gel

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Polyvinyl alcohol(PVA) physiological saline gel was prepared using physiological saline solution of the polymer by freezing and thawing method. The influences of the concentration of PVA, freezing and thawing cycle times and solvent swelling media on the swelling properties of PVA saline gel were investigated. The result show that the electrolytical ions have great effect on the swelling behavior of PVA saline gel. The equilibrium swelling ratio of PVA saline gel in aqueous swelling media is larger than that in saline swelling media. Also, the equilibrium swelling ratios of PVA saline gel in aqueous and in saline media decrease with the increase of gel concentration and the increase of freezing and thawing cycle times. The decreasing speed of equilibrium swelling ratio with the increase of freezing and thawing cycle times of PVA gel in distilled water is faster than that in physiological saline. The swelling kinetic equation can sufficiently describe the swelling behavior of PVA physiological saline gel.

  8. Effect of Subgingivally Delivered 10% Emblica officinalis Gel as an Adjunct to Scaling and Root Planing in the Treatment of Chronic Periodontitis - A Randomized Placebo-controlled Clinical Trial.

    Science.gov (United States)

    Grover, Shilpa; Tewari, Shikha; Sharma, Rajinder K; Singh, Gajendra; Yadav, Aparna; Naula, Satish C

    2016-06-01

    Emblica officinalis fruit possesses varied medicinal properties including cytoprotective antimicrobial, antioxidant, antiresorptive and antiinflammatory activity. The present study aimed to investigate the effect of subgingival application of indigenously prepared E. officinalis (Amla) sustained-release gel adjunctive to scaling and root planing (SRP) on chronic periodontitis. Forty-six patients (528 sites) were randomly assigned to control group (23;264): SRP +placebo gel and test group (23;264): SRP + 10% E. officinalis gel application. Periodontal parameters: plaque index, gingival index, probing pocket depth (PPD), clinical attachment level (CAL) and modified sulcus bleeding index (mSBI) were assessed at baseline, 2 and 3-month post-therapy. Forty patients (470 sites) completed the trial. When test and control sites were compared, significantly more reduction in mean PPD, mSBI, number of sites with PPD = 5-6 mm, PPD ≥ 7 mm, CAL ≥ 6 mm and greater CAL gain were achieved in test sites at 2- and 3-month post-therapy (p < 0.05). Locally delivered 10% E. officinalis sustained-release gel used as an adjunct to SRP may be more effective in reducing inflammation and periodontal destruction in patients with chronic periodontitis when compared with SRP alone. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26914986

  9. Soft, Comfortable Polymer Dry Electrodes for High Quality ECG and EEG Recording

    Directory of Open Access Journals (Sweden)

    Yun-Hsuan Chen

    2014-12-01

    Full Text Available Conventional gel electrodes are widely used for biopotential measurements, despite important drawbacks such as skin irritation, long set-up time and uncomfortable removal. Recently introduced dry electrodes with rigid metal pins overcome most of these problems; however, their rigidity causes discomfort and pain. This paper presents dry electrodes offering high user comfort, since they are fabricated from EPDM rubber containing various additives for optimum conductivity, flexibility and ease of fabrication. The electrode impedance is measured on phantoms and human skin. After optimization of the polymer composition, the skin-electrode impedance is only ~10 times larger than that of gel electrodes. Therefore, these electrodes are directly capable of recording strong biopotential signals such as ECG while for low-amplitude signals such as EEG, the electrodes need to be coupled with an active circuit. EEG recordings using active polymer electrodes connected to a clinical EEG system show very promising results: alpha waves can be clearly observed when subjects close their eyes, and correlation and coherence analyses reveal high similarity between dry and gel electrode signals. Moreover, all subjects reported that our polymer electrodes did not cause discomfort. Hence, the polymer-based dry electrodes are promising alternatives to either rigid dry electrodes or conventional gel electrodes.

  10. Soft, Comfortable Polymer Dry Electrodes for High Quality ECG and EEG Recording

    Science.gov (United States)

    Chen, Yun-Hsuan; de Beeck, Maaike Op; Vanderheyden, Luc; Carrette, Evelien; Mihajlović, Vojkan; Vanstreels, Kris; Grundlehner, Bernard; Gadeyne, Stefanie; Boon, Paul; Van Hoof, Chris

    2014-01-01

    Conventional gel electrodes are widely used for biopotential measurements, despite important drawbacks such as skin irritation, long set-up time and uncomfortable removal. Recently introduced dry electrodes with rigid metal pins overcome most of these problems; however, their rigidity causes discomfort and pain. This paper presents dry electrodes offering high user comfort, since they are fabricated from EPDM rubber containing various additives for optimum conductivity, flexibility and ease of fabrication. The electrode impedance is measured on phantoms and human skin. After optimization of the polymer composition, the skin-electrode impedance is only ∼10 times larger than that of gel electrodes. Therefore, these electrodes are directly capable of recording strong biopotential signals such as ECG while for low-amplitude signals such as EEG, the electrodes need to be coupled with an active circuit. EEG recordings using active polymer electrodes connected to a clinical EEG system show very promising results: alpha waves can be clearly observed when subjects close their eyes, and correlation and coherence analyses reveal high similarity between dry and gel electrode signals. Moreover, all subjects reported that our polymer electrodes did not cause discomfort. Hence, the polymer-based dry electrodes are promising alternatives to either rigid dry electrodes or conventional gel electrodes. PMID:25513825

  11. SYNTHESIS OF HIGH THERMOSTABLE SILICONE GELS CONSTRUCTED WITH LADDERLIKE POLYSILSESQUIOXANES

    Institute of Scientific and Technical Information of China (English)

    Huai-zhong Pan; Ming Cao; Jian-hua Luo; Ping Xie; Rong-ben Zhang; Yu-hui Lin; Neal Tai-sheng Chung

    2000-01-01

    Heat-resistant silicone gels were synthesized by replacing the single main chain polymethylhydrosiloxane with reactive ladderlike polyhydrosilsesquioxane copolymers. Because of the interaction between polydimethylsiloxane chains and the ladderlike polysilsesquioxanes chains, the cyclization of the polydimethylsiloxane chains is hindered. The high thermal stability of the ladderlike polymers can improve the thermal stability of the silicone gels without sacrificing their good comprehensive properties.

  12. On the Structure and Dynamics of Polyelectrolyte Gel Systems and Gel-surfactant Complexes

    OpenAIRE

    Råsmark, Per Johan

    2004-01-01

    This thesis describes the results of experimental work on polyelectrolyte gels and their interaction with oppositely charged surfactants, and presents two new algorithms applicable to the simulation of colloid and polymer systems. The model systems investigated were crosslinked poly(acrylate) (PA) and poly(styrene sulphonate) (PSS), and the surfactant was dodecyl trimethylammonium bromide (DoTAB). Pure gel materials were studied using dynamic light scattering. It was shown that the diffusion ...

  13. Nanoparticle solutions as adhesives for gels and biological tissues.

    Science.gov (United States)

    Rose, Séverine; Prevoteau, Alexandre; Elzière, Paul; Hourdet, Dominique; Marcellan, Alba; Leibler, Ludwik

    2014-01-16

    Adhesives are made of polymers because, unlike other materials, polymers ensure good contact between surfaces by covering asperities, and retard the fracture of adhesive joints by dissipating energy under stress. But using polymers to 'glue' together polymer gels is difficult, requiring chemical reactions, heating, pH changes, ultraviolet irradiation or an electric field. Here we show that strong, rapid adhesion between two hydrogels can be achieved at room temperature by spreading a droplet of a nanoparticle solution on one gel's surface and then bringing the other gel into contact with it. The method relies on the nanoparticles' ability to adsorb onto polymer gels and to act as connectors between polymer chains, and on the ability of polymer chains to reorganize and dissipate energy under stress when adsorbed onto nanoparticles. We demonstrate this approach by pressing together pieces of hydrogels, for approximately 30 seconds, that have the same or different chemical properties or rigidities, using various solutions of silica nanoparticles, to achieve a strong bond. Furthermore, we show that carbon nanotubes and cellulose nanocrystals that do not bond hydrogels together become adhesive when their surface chemistry is modified. To illustrate the promise of the method for biological tissues, we also glued together two cut pieces of calf's liver using a solution of silica nanoparticles. As a rapid, simple and efficient way to assemble gels or tissues, this method is desirable for many emerging technological and medical applications such as microfluidics, actuation, tissue engineering and surgery.

  14. Structure and Frictional Properties of Colloid Gel

    Directory of Open Access Journals (Sweden)

    Masayuki Tokita

    2014-03-01

    Full Text Available Polymer gels are known to be opaque when the preparation conditions, such as the reaction temperature and the composition, are changed. The increase of the opaqueness of the gel suggests strongly the change of network structure. Here, we are going to review the recent studies on the structure and the frictional study of the opaque poly(acrylamide gel. The results indicate that the opaque poly(acrylamide gel consists of the fractal aggregate of the colloidal particles of sub-micrometer in size. The density of the colloid particle is calculated from the structural parameters and is found to be of the order of about 1 g/cm3. The results indicate that the main chain component and the cross-linker is densely cross-linked into the particle. The frictional property of poly(acrylamide gel is analyzed in terms of the structural parameters of the gel. It is found that the frictional property of the opaque gel is well explained in terms of the structural parameters of the opaque gel.

  15. 溶胶-凝胶法制备含氟聚丙烯酸酯/SiO2杂化材料%Study On Fluoro-Acrylate Polymer/SiO2 Hybrids Prepared by Sol-Gel Process

    Institute of Scientific and Technical Information of China (English)

    钱斯文; 吴文健; 王建方; 刘长利; 张学骜

    2008-01-01

    Silica sols were synthesized by an acid-catalyzed sol-gel process,and fluoro-acrylate polymer/SiO2 hybrid materials were prepared by silica sols in-situ polymerized with acrylate monomers.The structure,morphologies and surface chemical composition of the hybrid system was characterized by FT-IR,FESEM and XPS.It was found that in the hybrid system,SiO2 subsisted in networks,and covalent linked with organic components.The effects of morphology,distribution and interfacial conditions of inorganic disperse phase on the surface,thermal and mechanical properties of hybrids were investigated.The result showed that with the increase of SiO2 content,the water contact angle,thermal stability and hardness of the hybrids were enhanced,but the adhesion of the hybrid coatings increased firstly and then decreased.%用酸催化溶胶-凝胶法制得SiO2溶胶,与丙烯酸酯单体原位聚合,制备了含氟聚丙烯酸酯/SiO2杂化材料.通过红外光谱、场发射扫描电镜、X射线光电子能谱对杂化材料的结构、形态及表面化学组成进行了表征,表明SiO2在杂化体系中以Si-O网络的形式存在,并且与有机相之间有良好键合.并研究了SiO2相的形态、分布和界面状况对杂化材料的表面性能、热学性能和力学性能的影响.测试结果证实,随着SiO2含量的增加,杂化材料的疏水性、热稳定性和硬度都逐渐增强,附着力则是先增大后减小.

  16. Investigation on polyethylene-supported and nano-SiO2 doped poly(methyl methacrylate-co-butyl acrylate) based gel polymer electrolyte for high voltage lithium ion battery

    International Nuclear Information System (INIS)

    Highlights: • P(MMA-co-BA)/nano-SiO2/PE based GPE was developed for high voltage lithium ion battery. • P(MMA-co-BA)/nano-SiO2/PE has uniform and interconnected pore structure. • The GPE exhibits improved ionic conductivity and compatibility with electrodes. • 5 V battery using the GPE presents excellent cyclic stability. - Abstract: Nano-SiO2 as dopant was used for preparing polyethylene-supported poly(methyl methacrylate-co-butyl acrylate) (P(MMA-co-BA)/PE) based membrane and corresponding gel polymer electrolyte (GPE), which is applied to improve the cyclic stability of high voltage lithium ion battery. P(MMA-co-BA)/nano-SiO2/PE based membranes and corresponding GPEs were characterized with scanning electron spectroscopy, X-ray diffraction, electrochemical impedance spectroscopy, mechanical test, thermogravimetric analysis, linear sweep voltammetry, and charge/discharge test. It is found that the GPE with 5 wt.% nano-SiO2 shows the best performance. Compared to the undoped membrane, the 5 wt.% nano-SiO2 doped membrane has a better pore structure and higher electrolyte uptake, leading to the enhancement in ionic conductivity of the resulting GPE from 1.23 × 10−3 to 2.26 × 10−3 S.cm−1 at room temperature. Furthermore, the thermal stability of the doped membrane is increased from 300 to 320 °C while its decomposition potential of GPE is from 5.0 to 5.6 V (vs. Li/Li+). The cyclic stability of Li/GPE/Li(Li0.13Ni0.30Mn0.57)O2 cell at the high voltage range of 3.5 V ∼ 5.0 V is consequently improved, the capacity retention of the cell using the doped membrane is 92.8% after 50 cycles while only 88.9% for the cell using undoped membrane and 66.9% for the cell using liquid electrolyte

  17. Lactate solid-state biosensor with multilayer of electrodeposited polymers for flow-injection clinical analysis.

    Science.gov (United States)

    Krawczyñski vel Krawczyk, T; Trojanowicz, M; Lewenstam, M; Moszczynska, A

    1996-01-01

    In the lactate biosensor, electrodeposited poly(o-phenylenediamine) serves as a convenient matrix for the immobilization of lactate oxidase, but does not provide sufficient discrimination from several interfering species present in physiological fluids. Their effect, however, can be eliminated by additional modification of the working Pt electrode with a bilayer of electrodeposited polypyrrole/polyphenol. Despite continued decrease in biosensor sensitivity, the newly developed three-layer solid-state biosensor was successfully applied in flow-injection determination of lactate in both undiluted and diluted human blood serum samples over a 10 day period. For the lactate concentration range 0.2-5.0 mM in several series of measurements the correlation coefficient values for comparison with photometric determination using a DuPont dimension clinical analyzer were between 0.96 and 0.99. The reproducibility measured for 1:10 diluted serum was 0.6%. The detection limit was estimated as 2 microM. PMID:8828166

  18. Clinical performance of a dermal filler containing natural glycolic Acid and a polylactic Acid polymer: results of a clinical trial in human immunodeficiency virus subjects with facial lipoatrophy.

    Science.gov (United States)

    Tagle, Jorge M; Macchetto, Pedro Cervantes; Durán Páramo, Rosa Margarita

    2010-02-01

    Lipoatrophy is a condition that affects certain individuals, most commonly those who are infected with the human immunodeficiency virus.(1-3) Injectable fillers are used for the treatment of these dermal contour deformities to smooth dermal depressions formed by the loss of volume. These dermal fillers (also known as soft tissue augmentation devices) can correct contour deformities caused by lipoatrophy in patients who are human immunodeficiency virus positive or negative. The product used in this study is a patented, second-generation, injectable, dermal collagen stimulator that combines glycolic acid and polylactic acid. The glycolic acid used is not a polymer, but rather an acid derived from sugar cane. Its chemical structure corresponds to that of an alpha-hydroxy acid. Glycolic acid is a well-characterized agent that is present in a number of cosmetic products. Polylactic acid is a synthetic, biocompatible, biodegradable, inert, synthetic polymer from the poly a-hydroxy-acid family that is believed to stimulate fibroblasts to produce more collagen, thus increasing facial volume. Together, polylactic acid and glycolic acid act in concert to 1) stimulate collagen production and 2) hydrate the outer layers of the skin. A multicenter, clinical investigation authorized by the Mexican Secretariat of Health was conducted between September 20, 2002, and September 19, 2004. This clinical study was conducted in male patients between 32 and 60 years of age with lipoatrophy as a result of highly active antiretroviral therapy for human immunodeficiency virus infection. The study objective was to measure the improvement of contour deformities after the injection of a dermal collagen stimulator containing glycolic acid and polylactic acid. In addition to safety, this dermal filler was assessed when used to correct volume deformities caused by lipoatrophy in subjects who are human immunodeficiency virus positive. Thirty male subjects participated and were treated as follows

  19. Biopolymer gel swelling analysed with scaling laws and Flory-Rehner theory

    NARCIS (Netherlands)

    Sman, van der R.G.M.

    2015-01-01

    The swelling of biopolymer gels is analysed with scaling laws from polymer physics, as an alternative for the classical Flory-Rehner theory. With these scaling laws, holding for polymer concentrations in the semi-dilute regime, experimental data on deswelling of gels can be collapsed to a single

  20. Stability of the response and dependence of the optical signal as function of dose rate of the alanine gel dosimeter for electron clinic beams

    International Nuclear Information System (INIS)

    This work evaluates the stability of response and the dependence on the optical response of dose rate of the alanine gel solution developed at the IPEN, Sao Paulo, Brazil, for possible future usage as 3D dosemeter in the medical area, as the area is lack of measure instrumentation for three dimension dose

  1. Kinetics of swelling of polyelectrolyte gels: Fixed degree of ionization

    Science.gov (United States)

    Sen, Swati; Kundagrami, Arindam

    2015-12-01

    The swelling kinetics of uncharged and charged polymer (polyelectrolyte) gels in salt-free conditions is studied in one dimension by solving the constitutive equation of motion (Newton's law for the elementary gel volume) of the displacement variable by two theoretical methods: one in which the classical definition of stress is used with the bulk modulus taken as a parameter, and the other in which a phenomenological expression of the osmotic stress as a function of polymer density and degree of ionization is taken as an input to the dynamics. The time-evolution profiles for spatially varying polymer density and stress, along with the location of the gel-solvent interface, are obtained from the two methods. We show that both the polymer density (volume fraction) and stress inside the gel follow expected behaviours of being maximum for the uniformly shrunken gel, and relaxing slowly to the lowest values as the gel approaches equilibrium. We further show that, by comparing the temporal profiles of the gel-solvent interface and other variables between the two methods, one may attempt to assign an effective bulk modulus to the polyelectrolyte gel as a function of the degree of ionization and other parameters of the gel such as hydrophobicity, cross-link density, and the temperature. The major result we get is that the effective bulk modulus of a polyelectrolyte gel increases monotonically with its degree of ionization. In the process of identifying the parameters for a monotonic swelling, we calculated using a well-known expression of the free energy the equilibrium results of two-phase co-existence and the critical point of a polyelectrolyte gel with a fixed degree of ionization.

  2. Kinetics of swelling of polyelectrolyte gels: Fixed degree of ionization

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Swati; Kundagrami, Arindam, E-mail: arindam@iiserkol.ac.in [Department of Physical Sciences, Indian Institute of Science Education and Research, Kolkata, Mohanpur 741246, West Bengal (India)

    2015-12-14

    The swelling kinetics of uncharged and charged polymer (polyelectrolyte) gels in salt-free conditions is studied in one dimension by solving the constitutive equation of motion (Newton’s law for the elementary gel volume) of the displacement variable by two theoretical methods: one in which the classical definition of stress is used with the bulk modulus taken as a parameter, and the other in which a phenomenological expression of the osmotic stress as a function of polymer density and degree of ionization is taken as an input to the dynamics. The time-evolution profiles for spatially varying polymer density and stress, along with the location of the gel-solvent interface, are obtained from the two methods. We show that both the polymer density (volume fraction) and stress inside the gel follow expected behaviours of being maximum for the uniformly shrunken gel, and relaxing slowly to the lowest values as the gel approaches equilibrium. We further show that, by comparing the temporal profiles of the gel-solvent interface and other variables between the two methods, one may attempt to assign an effective bulk modulus to the polyelectrolyte gel as a function of the degree of ionization and other parameters of the gel such as hydrophobicity, cross-link density, and the temperature. The major result we get is that the effective bulk modulus of a polyelectrolyte gel increases monotonically with its degree of ionization. In the process of identifying the parameters for a monotonic swelling, we calculated using a well-known expression of the free energy the equilibrium results of two-phase co-existence and the critical point of a polyelectrolyte gel with a fixed degree of ionization.

  3. Rheological, mucoadhesive and release properties of pluronic F-127 gel and pluronic F-127/polycarbophil mixed gel systems.

    Science.gov (United States)

    Tirnaksiz, F; Robinson, J R

    2005-07-01

    This study was designed to combine the mucoadhesive property of Noveon and the thermosensitive property of Pluronic F-127 into one gel system. A rheological study of Pluronic aqueous sols (10-35%), Noveon gels (0.5-2%) and of mixed gels containing Pluronic (10-17.5%) and polycarbophil (0.5-2.5%) was conducted at different temperatures (15-35 degrees C). The viscosity of Pluronic sols increased with an increase in temperature and the mixed gels had thermoreversible property. The viscosity of mixed gels was higher than that of the Pluronic sols containing only Pluronic because of the increase in total polymer concentration. No interaction was found between -COOH groups of Noveon and Pluronic molecules at the studied concentrations of polymers; the viscosity of mixed gels containing un-neutralized Noveon was lower than that of the neutralized mixed gels. The effect of Pluronic F-127 on the mucoadhesive property of Noveon was investigated. The mucoadhesive properties of Pluronic and Noveon gels were compared by a force of detachment test. It was found that Pluronic and Noveon gels showed approximately the same mucoadhesive strength. However, there were significant differences in the viscosity of Noveon and Pluronic gels. The adhesive force of the mixed gel was almost same as that of the Noveon gel. The Pluronic did not affect the adhesive power of Noveon and the increased viscosity did not affect the bioadhesive force of the mixed gels. In spite of increasing viscosity of the gel, the percentage of released model material (mannitol) increased with increasing temperature. This is based on the previously reported observation that the interaction between the Pluronic molecules squeezed mannitol molecules out of the polymer chains. The mannitol release obeyed zero-order kinetics and the flux values of mixed gels at 15 and 35 degrees C were very similar. The Noveon chains among Pluronic chains probably hindered the diffusion of mannitol molecules and the release was thus

  4. Sandy soil plantation in semi-arid zones by polyacrylamide gel conditioner prepared by ionizing radiation. Part of a coordinated programme on radiation modified polymers for biomedical and biochemical applications

    International Nuclear Information System (INIS)

    Polyacrylamide gel prepared by ionizing radiation was found to be capable of furnishing adequate conditions for sandy-soil plantation in semi-arid zones. The gel can be tailored for any soil texture under various climatic conditions. The sand-gel combination maintains three cycles of complete destruction and reformation without significant changes in erosion index. Water holding capacity and retention at different suctions in treated sand are increased. This increases water use efficiency. Fertilizers use efficiency is also increased to almost three times that of fertile clayey soil

  5. Polymer Electrolytes for Lithium/Sulfur Batteries

    Directory of Open Access Journals (Sweden)

    The Nam Long Doan

    2012-08-01

    Full Text Available This review evaluates the characteristics and advantages of employing polymer electrolytes in lithium/sulfur (Li/S batteries. The main highlights of this study constitute detailed information on the advanced developments for solid polymer electrolytes and gel polymer electrolytes, used in the lithium/sulfur battery. This includes an in-depth analysis conducted on the preparation and electrochemical characteristics of the Li/S batteries based on these polymer electrolytes.

  6. Internal structure analysis of particle-double network gels used in a gel organ replica

    Science.gov (United States)

    Abe, Mei; Arai, Masanori; Saito, Azusa; Sakai, Kazuyuki; Kawakami, Masaru; Furukawa, Hidemitsu

    2016-04-01

    In recent years, the fabrication of patient organ replicas using 3D printers has been attracting a great deal of attention in medical fields. However, the cost of these organ replicas is very high as it is necessary to employ very expensive 3D printers and printing materials. Here we present a new gel organ replica, of human kidney, fabricated with a conventional molding technique, using a particle-double network hydrogel (P-DN gel). The replica is transparent and has the feel of a real kidney. It is expected that gel organ replicas produced this way will be a useful tool for the education of trainee surgeons and clinical ultrasonography technologists. In addition to developing a gel organ replica, the internal structure of the P-DN gel used is also discussed. Because the P-DN gel has a complex structure comprised of two different types of network, it has not been possible to investigate them internally in detail. Gels have an inhomogeneous network structure. If it is able to get a more uniform structure, it is considered that this would lead to higher strength in the gel. In the present study we investigate the structure of P-DN gel, using the gel organ replica. We investigated the internal structure of P-DN gel using Scanning Microscopic Light Scattering (SMILS), a non-contacting and non-destructive.

  7. Methods of Manufacturing Bioactive Gels from Extracellular Matrix Material

    Science.gov (United States)

    Kentner, Kimberly A. (Inventor); Stuart, Katherine A. (Inventor); Janis, Abram D. (Inventor)

    2016-01-01

    The present invention is directed to methods of manufacturing bioactive gels from ECM material, i.e., gels which retain bioactivity, and can serve as scaffolds for preclinical and clinical tissue engineering and regenerative medicine approaches to tissue reconstruction. The manufacturing methods take advantage of a new recognition that bioactive gels from ECM material can be created by digesting particularized ECM material in an alkaline environment and neutralizing to provide bioactive gels.

  8. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2008-12-30

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  9. Mechanism of Concentration Dependence of Water Diffusivity in Polyacrylate Gels

    Science.gov (United States)

    Mani, Sriramvignesh; Khabaz, Fardin; Khare, Rajesh

    Membrane based separation processes offer an energy efficient alternative to traditional distillation based separation processes. In this work, we focus on the molecular mechanisms underlying the process of separation of dilute ethanol-water mixture using polyacrylate gels as pervaporation membranes. The diffusivities of the components in swollen gels exhibit concentration dependence. We have used molecular dynamics (MD) simulations to study the correlation between the dynamics of solvent (water and ethanol) molecules, polymer dynamics and solvent structure in the swollen gel systems as a function of solvent concentration. Three different polyacrylate gels were studied: (1) poly n-butyl acrylate (PBA), (2) copolymer of butyl acrylate and 2-hydroxyethyl acrylate P(BA50-HEA50), and (3) poly 2-hydroxyethyl acrylate (PHEA). Simulation results show that solvent concentration has a significant effect on local structure of the solvent molecules and chain dynamics; these factors (local structure and chain dynamics), in turn, affect the diffusivity of these molecules. At low concentration, solvent molecules are well dispersed in the gel matrix and form hydrogen bonds with the polymer. Solvent mobility is correlated with polymer mobility in this configuration and consequently water and ethanol molecules exhibit slower dynamics, this effect is especially significant in PHEA gel. At high solvent concentration, water molecules form large clusters in the system accompanied by enhancement in mobility of both the gel network and the solvent molecules.

  10. A NOVEL OPHTHALMIC DRUG DELIVERY SYSTEM: IN-SITU GEL

    Directory of Open Access Journals (Sweden)

    A.P. Patil*, A.A. Tagalpallewar, G.M. Rasve, A.V. Bendre, P.G. Khapekar

    2012-09-01

    Full Text Available The ophthalmic in-situ gels now days proved an palpable sustained drug delivery in various eye diseases. The formulation of in-situ gels for eye which carries the advantages like easy for administration, reduces frequency of dose and improves patient compliance. The formation of in-situ gels depends on phase transition system or sol-gel transition system. The formulation approaches like temperature intonation, pH change and presence of ions from which the drug gets released in a sustained and controlled manner are utilised for in-situ gels. Various polymers that are used for the formulation of in-situ gels include chitosan, Pluronic F-127, poly-caprolactone, gellan gum, alginic acid, xyloglucan, pectin etc.

  11. 中药复方凝胶剂治疗奶牛乳房炎的临床药效学研究%Study on Clinical Effects of Compound Chinese Medicine Gels on Dairy Mastitis

    Institute of Scientific and Technical Information of China (English)

    翁春玲; 武瑞

    2015-01-01

    Mastitis is one of the primary diseases in dairy industry, which have a large effect on the output of milk and dairy qualitative.This experiment researched the self-developed Chinese medicine gels through clinical pharmacodynamics study, so that the clinical treatment effect was confimed. Thus for prevention and cure cow mastitis in production, it can provide theoretical guidance and effective product. Experimental results showed that Chinese medicine gels agent had good curative effect on clinical mastitis and sub mastitis. The treatment efifciency of clinical mastitis was amount to 70%, and so as to sub mastitis, it can signiifcantly reduce somatic cell number, but had no signiifcant inlfuence on milk fat rate, milk protein rate and the content of lactose and dry matter.%乳房炎是危害奶牛业的主要疾病之一,严重影响产奶量和乳品质。本试验通过对自主研制的复方中药凝胶剂的临床药效学研究,确定其临床治疗效果,从而为生产中防治奶牛乳房炎提供理论指导和有效产品。试验结果表明:中药复方凝胶剂对临床型乳房炎和隐性乳房炎均具有较好的疗效。对临床型乳房炎的治疗有效率达70%,对隐性乳房炎可显著降低乳体细胞数,对乳脂率、乳蛋白率、乳糖含量及乳中干物质无任何显著影响。

  12. Effectiveness of 0.2% chlorhexidine gel and a eugenol-based paste on postoperative alveolar osteitis in patients having third molars extracted: a randomised controlled clinical trial.

    Science.gov (United States)

    Jesudasan, James Solomon; Wahab, P U Abdul; Sekhar, M R Muthu

    2015-11-01

    The aim of this study was to compare the effect of application of 0.2% chlorhexidine gel, a eugenol-based paste, together with a control group on the postoperative incidence of alveolar osteitis in patients having third molars extracted. A total of 270 patients who had this procedure at the Dept of Oral and Maxillofacial Surgery, Saveetha Dental College and who met the inclusion criteria were enrolled in the study and divided into 3 groups: the first had a 0.2% chlorhexidine-based gel applied to the alveolar socket once after extraction; the second had a eugenol-based paste applied to the alveolar socket once after extraction; and the third group acted as controls, with no treatment. The incidence of alveolar osteitis was recorded for 7 days. We also recorded postoperative pain, inflammation, infection, and wound healing. Nine of the control group (10%) and 2 (2%) of the chlorhexidine group developed alveolar osteitis on the seventh postoperative day. The overall incidence (11/270) was 4%, which is less than reported elsewhere. The distribution of alveolar osteitis among the 3 groups was significant (p=0.002), with the eugenol group having no cases. The chlorhexidine group showed less incidence of alveolar osteitis than other reported studies and also less pain, inflammation, infection, and better wound healing than the control group. We conclude that eugenol was the better of the 2 interventions.

  13. Analysis of the insulin receptor gene in noninsulin-dependent diabetes mellitus by denaturing gradient gel blots: A clinical research center study

    Energy Technology Data Exchange (ETDEWEB)

    Magre, J.; Goldfine, A.B.; Warram, J.H. [Harvard Medical School, Boston, MA (United States)] [and others

    1995-06-01

    We have used a new technique of denaturing gradient gel blotting to determine the prevalence of alterations in the intracellular domain of the insulin receptor in normal individuals and subjects with non-insulin-dependent diabetes mellitus (NIDDM). This method detects DNA sequence differences as restriction fragment melting polymorphisms (RFMP) and is sensitive to changes in sequence at both restriction sites and within the fragments themselves. Using restriction digests with AluI, HaeIII, HinfI, RsaI, Sau3A, and Sau96, 12 RFMPs were found to localize to the region of the {beta}-subunit of the insulin receptor gene. Using exon-specific probes, these RFMPs could be localized to specific regions surrounding individual exons, including exons, 14, 15, 16, 18, 20, and 22. In general, linkage disequilibrium between polymorphisms was inversely related to their distance in the gene structure, although there was a {open_quotes}hot spot{close_quotes} for recombination between exons 19 and 20. No difference in melting temperatures or allele frequency was observed between NIDDM patients and controls. These data indicate that the region of the insulin receptor gene coding for the intracellular portion of the {beta}-subunit is highly polymorphic and that polymorphisms surrounding specific exons can be identified by denaturing gradient gel blotting, but there is no evidence that variation at this locus contributes to NIDDM susceptibility in most individuals. 36 refs., 3 figs., 3 tabs.

  14. Cycling performances of Li/LiCoO2 cell with polymer-coated separator

    International Nuclear Information System (INIS)

    Gel polymer electrolyte (GPE) was prepared with the porous polymer-coated separator by soaking in an electrolyte solution. The porous polymer coated on both sides of polyethylene separator was gelled in contact with the electrolyte solution and encapsulated a larger amount of electrolyte solution. The gel polymer electrolyte exhibited high ionic conductivity in order of 10-3 S/cm and was electrochemically stable up to 4.9 versus Li. With the gel polymer electrolyte, lithium metal polymer cell composed of a lithium anode and LiCoO2 cathode was assembled and its cycling performances were evaluated

  15. The viscoelastic effect in bending bucky-gel actuators

    Science.gov (United States)

    Kruusamäe, Karl; Mukai, Ken; Sugino, Takushi; Asaka, Kinji

    2014-03-01

    Electromechanically active polymers (EAP) are considered a good actuator candidate for a variety of reasons, e.g. they are soft, easy to miniaturize and operate without audible noise. The main structural component in EAPs is, as the name states, a type of deformable polymer. As polymers are known to exhibit a distinct mechanical response, the nature of polymer materials should never be neglected when characterizing and modeling the performance of EAP actuators. Bucky-gel actuators are a subtype of EAPs where ion-containing polymer membrane acts as an electronically insulating separator between two electrodes of carbon nanotubes and ionic liquid. In many occasions, the electrodes also contain polymer for the purpose of binding it together. Therefore, mechanically speaking, bucky-gel actuators are composite structures with layers of different mechanical nature. The viscoelastic response and the shape change property are perhaps the most characteristic effects in polymers. These effects are known to have high dependence on factors such as the type of polymer, the concentration of additives and the structural ratio of different layers. At the same time, most reports about optimization of EAP actuators describe the alteration of electromechanical performance dependent on the same factors. In this paper, the performance of bucky-gel actuators is measured as a function between the output force and bending deflection. It is observed that effective stiffness of these actuators depends on the input voltage. This finding is also supported by dynamic mechanical analysis which demonstrates that the viscoelastic response of bucky-gel laminate depends on both frequency and temperature. Moreover, the dynamic mechanical analysis reveals that in the range of standard operation temperatures, tested samples were in their glass transition region, which made it possible to alter their shape by using mechanical fixing. The mechanical fixity above 90% was obtained when high

  16. Macromolecular recognition: Recognition of polymer side chains by cyclodextrin

    Science.gov (United States)

    Hashidzume, Akihito; Harada, Akira

    2015-12-01

    The interaction of cyclodextrins (CD) with water soluble polymers possessing guest residues has been investigated as model systems in biological molecular recognition. The selectivity of interaction of CD with polymer-carrying guest residues is controlled by polymer chains, i.e., the steric effect of polymer main chain, the conformational effect of polymer main chain, and multi-site interaction. Macroscopic assemblies have been also realized based on molecular recognition using polyacrylamide-based gels possessing CD and guest residues.

  17. Microporous polymer electrolyte based on PVDF-PEO

    Institute of Scientific and Technical Information of China (English)

    LI Jian; XI Jingyu; SONG Qing; TANG Xiaozhen

    2005-01-01

    @@ Since Wright et al.[1] found that the complex of PEO/alkali metals salt had the ability of ionic conductivity in 1973, in-depth studies have been carried out about various polymer electrolytes, which were applied to replacing the liquid electrolytes in lithium ion battery[2,3]. At present, polymer electrolytes mainly include three kinds: dry polymer electrolytes, gel polymer electrolytes and microporous polymer electrolytes.

  18. Screening of mucoadhesive vaginal gel formulations

    Directory of Open Access Journals (Sweden)

    Ana Ochoa Andrade

    2014-12-01

    Full Text Available Rational design of vaginal drug delivery formulations requires special attention to vehicle properties that optimize vaginal coating and retention. The aim of the present work was to perform a screening of mucoadhesive vaginal gels formulated with carbomer or carrageenan in binary combination with a second polymer (carbomer, guar or xanthan gum. The gels were characterised using in vitroadhesion, spreadability and leakage potential studies, as well as rheological measurements (stress and frequency sweep tests and the effect of dilution with simulated vaginal fluid (SVF on spreadability. Results were analysed using analysis of variance and multiple factor analysis. The combination of polymers enhanced adhesion of both primary gelling agents, carbomer and carrageenan. From the rheological point of view all formulations presented a similar behaviour, prevalently elastic and characterised by loss tangent values well below 1. No correlation between rheological and adhesion behaviour was found. Carbomer and carrageenan gels containing the highest percentage of xanthan gum displayed good in vitro mucoadhesion and spreadability, minimal leakage potential and high resistance to dilution. The positive results obtained with carrageenan-xanthan gum-based gels can encourage the use of natural biocompatible adjuvants in the composition of vaginal products, a formulation field that is currently under the synthetic domain.

  19. Rapid serum agglutination and agar gel immunodiffusion tests associated to clinical signs in rams experimentally infected with Brucella ovis Teste de soro aglutinação rápida e do teste de imunodifusão em gel de ágar associados aos sinais clínicos em carneiros infectados experimentalmente com Brucella ovis

    Directory of Open Access Journals (Sweden)

    Cristiane Nakada Nozaki

    2011-08-01

    Full Text Available The purpose of this study was to evaluate the agar gel immunodiffusion and the rapid serum agglutination tests associated to clinical signs in rams experimentally infected with Brucella ovis. The serological profile during the 12 months of infection showed a large fluctuation of antibodies that favors the failure in the diagnostic. The evaluation of tests after the experimental infection allowed to suggest that none of the tests were able to detect the infection throughout the period of study. The study reinforces the importance of considering the clinical signs to support the diagnosis of Brucella ovis infection in rams.O objetivo deste estudo foi avaliar o uso do teste de imunodifusão em gel de ágar e o teste sorológico de aglutinação rápida comparados aos sinais clínicos em carneiros infectados experimentalmente com Brucella ovis para o diagnóstico confirmatório da brucelose ovina. O perfil sorológico durante os 12 meses pós-infecção mostrou flutuação da resposta por anticorpos, que favorece a falha no diagnóstico. A avaliação dos testes indicou que nenhum dos testes foi capaz de detectar a infecção durante todo o período de estudo. O estudo ressalta a importância de considerar os sinais clínicos para apoiar o diagnóstico confirmatório da infecção por Brucella ovis em carneiros.

  20. Physical gelation in polymer-nanofiller systems

    Science.gov (United States)

    Xu, Di; Gersappe, Dilip

    2015-03-01

    Polymer gelation by physically crosslinking to sheet-like nanofillers was studied by Molecular Dynamics simulation. Nanofillers were modeled as rigid bodies of disk-like shapes and crosslinks were simulated by introducing a short-range attraction between the nanofillers and polymer chain ends. The structure, dynamics and mechanics of this polymer gel was studied as function of nanofiller volume fraction. Micelle like clusters were formed by polymers wrapping around nanofillers as its cores. These structures grow, with increased filler fraction, into fibrous structures. We observe the formation of a percolated nework of these fibrous structures, with ordered local structure but disordered globally, as we increase the filler fraction. The dynamics of polymers showed significant caging at intermediate time, in gel state, while the polymers move heterogeneously. Stress autocorrelation and elongation results were analyzed as a function of the nano-filler concentration.

  1. Optical materials by a modified sol-gel nanoparticle process

    OpenAIRE

    Schmidt, Helmut K.; Mennig, Martin

    2000-01-01

    The use of sol-gel derived nanoparticles leads to interesting new materials and systems for optics. The basic principle, to combine transparent matrices with nanoparticles in sizes below remarkable scattering losses opens up new material technologies. The processing is almost as simple as sol-gel processing, and the use of polymerizable nanoparticle even leads to high performance coatings by using simple polymer techniques.

  2. Clinical therapeutic effect of herbal facial mask combined with adapalene gel in treatment of acne vulgaris%中药面膜联合阿达帕林凝胶治疗寻常痤疮的临床观察

    Institute of Scientific and Technical Information of China (English)

    江从军; 金慧玲

    2014-01-01

    目的:评价中药面膜联合0.1%阿达帕林凝胶治疗轻、中度寻常痤疮的临床疗效及安全性。方法寻常痤疮76例,随机分为两组,治疗组40例,采用中药面膜联合0.1%阿达帕林凝胶治疗;对照组36例,单独使用0.1%阿达帕林凝胶治疗。两组均在治疗6周后观察疗效并评价安全性。结果试验组、对照组的总有效率在第6周时分别为82.5%和52.7%,具有明显的差异。在治疗过程中,两组均未见明显不良反应。结论中药面膜联合0.1%阿达帕林凝胶治疗轻、中度寻常痤疮较单用阿达帕林疗效显著,见效快,病程短,无明显不良反应。%Objective To evaluate the clinical efficacy and safety of the combination therapy of herbal facial mask with 0.1%adapalene gel in patients with mild and moderate acne vulgaris .Methods A total of 76 patients with mild to moderate acne vulgaris were enrolled and randomly divided into 2 groups:40 cases in treatment group which were treated by herbal facial mask combined with 0.1%adapalene gel;36 cases in control group which were treated only by 0.1%adapalene gel .All the patients received therapy for 6 weeks continuously and had been observed to evaluate the efficacy and safety on the sixth week of treatment .Results On the sixth week of treatment, the total effective rate of treatment group was 82.5%, and there was a significant difference compared with the control group ( 52.7%) .All these 2 groups had not obvious side-effect during treatment . Conclusions Herbal facial mask combined with 0.1% adapalene gel therapy is more effective than adapalene monotherapy in mild to moderate acne cases with a rapid response and similar adverse reactions .

  3. The effect of polysaccharides on the ability of whey protein gels to either store or dissipate energy upon mechanical deformation

    NARCIS (Netherlands)

    Munialo, C.D.; Linden, van der E.; Ako, K.; Nieuwland, M.; As, van H.; Jongh, de H.H.J.

    2016-01-01

    The addition of polysaccharides to proteins during gel formation can alter the mechanical and textural properties of the resultant gels. However, the effect of addition of different polymers on mechanical properties of whey protein (WP) gels including their ability to elastically store energy, often

  4. Microfluidics of soft granular gels

    Science.gov (United States)

    Nixon, Ryan; Bhattacharjee, Tapomoy; Sawyer, W. Gregory; Angelini, Thomas E.

    Microfluidic methods for encapsulating cells and particles typically involve drop making with two immiscible fluids. The main materials constraint in this approach is surface tension, creating inherent instability between the two fluids. We can eliminate this instability by using miscible inner and outer phases. This is achieved by using granular micro gels which are chemically miscible but physically do not mix. These microgels are yield stress materials, so they flow as solid plugs far from shear gradients, and fluidize where gradients are generated - near an injection nozzle for example. We have found that tuning the yield stress of the material by varying polymer concentration, device performance can be controlled. The solid like behavior of the gel allows us to produces infinitely stable jets that maintain their integrity and configuration over long distances and times. These properties can be combined and manipulated to produce discrete particulate bunches of an inner phase, flowing inside of an outer phase, well enough even to print a Morse code message suspended within flow chambers about a millimeter in diameter moving at millimeters a second.

  5. Stage-specific analysis of plasma protein profiles in ovarian cancer: Difference in-gel electrophoresis analysis of pooled clinical samples

    Directory of Open Access Journals (Sweden)

    Mark J Bailey

    2013-01-01

    Full Text Available Introduction: Ovarian cancer is the leading cause of death from gynecological cancer. Non-specific symptoms early in disease and the lack of specific biomarkers hinder early diagnosis. Multi-marker blood screening tests have shown promise for improving identification of early stage disease; however, available tests lack sensitivity, and specificity. Materials and Methods: In this study, pooled deeply-depleted plasma from women with Stage 1, 2 or 3 ovarian cancer and healthy controls were used to compare the 2-dimensional gel electrophoresis (2-DE protein profiles and identify potential novel markers of ovarian cancer progression. Results/Discussion: Stage-specific variation in biomarker expression was observed. For example, apolipoprotein A1 expression is relatively low in control and Stage 1, but shows a substantial increase in Stage 2 and 3, thus, potential of utility for disease confirmation rather than early detection. A better marker for early stage disease was tropomyosin 4 (TPM4. The expression of TPM4 increased by 2-fold in Stage 2 before returning to "normal" levels in Stage 3 disease. Multiple isoforms were also identified for some proteins and in some cases, displayed stage-specific expression. An interesting example was fibrinogen alpha, for which 8 isoforms were identified. Four displayed a moderate increase at Stage 1 and a substantial increase for Stages 2 and 3 while the other 4 showed only moderate increases. Conclusion: Herein is provided an improved summary of blood protein profiles for women with ovarian cancer stratified by stage.

  6. A Gel Formulation Containing a New Recombinant Form of Manganese Superoxide Dismutase: A Clinical Experience Based on Compassionate Use-Safety of a Case Report

    Directory of Open Access Journals (Sweden)

    Lucia Grumetto

    2016-01-01

    Full Text Available Background. We report a case of bilateral posterior subcapsular cataracts (PSCs in a 24-year-old man with an allergic conjunctivitis history caused by a long-term therapy with glucocorticoids. Case Presentation. The patient showed a visual acuity of 9/10 for both eyes. He followed a therapy with ketotifen and bilastine for four years. During the last six months before our evaluation, he was treated with chloramphenicol and betamethasone, interrupted for onset of cataracts and increased intraocular pressure. We treated him with ophthalmic gel preparation containing a new recombinant form of manganese superoxide dismutase (rMnSOD at a concentration of 12.5 μg/mL, only for the right eye, while left eye was treated with standard protocol of Bendazac-lysine g 0.5. Conclusion. This case report shows the protective effects of rMnSOD versus PSC disease, probably due to the capacity of rMnSOD of countering free radical species.

  7. Identification of vaginal bacteria diversity and it's association with clinically diagnosed bacterial vaginosis by denaturing gradient gel electrophoresis and correspondence analysis.

    Science.gov (United States)

    Xia, Qing; Cheng, Lijuan; Zhang, Hua; Sun, Shangwen; Liu, Fang; Li, Hao; Yuan, Jing; Liu, Zhendong; Diao, Yutao

    2016-10-01

    Bacterial vaginosis (BV) is a common complex associated with numerous adverse health outcomes, affecting women of different ages throughout the world. The etiology of BV remains poorly understood due to the difficulty of establishing a molecular genetic criterion to recognize the vaginal microbiota of BV-positive women from that of the normal women. We used techniques of broad-range PCR-DGGE and gel imaging analysis system cooperated with 16S rRNA gene sequencing and statistical analysis to investigate the community structure of the healthy and BV-affected vaginal microbial ecosystems. The community of vaginal bacteria detected in subjects with BV was far more luxuriant and diverse than in subjects without BV. The mean number of microbial species in 128 BV-positive women was nearly two times greater than in 68 subjects without BV(4.05±1.96 versus 2.59±1.14). Our sequencing efforts yielded many novel phylotypes (198 of our sequences represented 59 species), including several novel BV-associated bacteria (BVAB) and many belonging to opportunistic infections, which remain inexplicable for their roles in determining the health condition of vaginal microflora. This study identifies Algoriphagus aquatilis, Atopobium vaginae, Burkholderia fungorum, Megasphaera genomosp species as indicators to BV and subjects with BV harbor particularly taxon-rich and diverse bacterial communities. Maybe Bifidobacterium, Staphylococcus or even more alien species are commensal creatures in normal vaginal microbiota. PMID:27503595

  8. Creation of Functional Organic Gels Based on Oligothiophenes

    Institute of Scientific and Technical Information of China (English)

    Liu Ping; Zhao Qi-zhong; Hu Jian-hua; Zhou Xiao-ping; Deng Wen-ji; Xu Yun-hua

    2004-01-01

    Polymer gels have received a great deal of attention not only from scientific interest but also for their practical applications. Recently, low molecular-weight organic gels have also been receiving growing attention. However, their have been few studies of low molecular-weight organic gels in contrast to extensive studies of polymer gels.In order to develop a novel class of low-molecular-weight organic gels and to gain an insight into the relationship between molecular structures of gel-forming compounds and gel-forming properties, a novel family of low molecular-weight organic compounds containing oligothiophene,N,N'-distearyl-5,5"-(2,2':5',2"-terthiophe-ne)dicarboxamide(DNC183T),N,N'-dialkyl-5,5"-(3,3"-dioctyl-2,2':5',2"-terthiophene)dicarboxamide(DNCnDOc3T, n = 5, 8, 16, 18)and N,N'-distearyl-5,5'"-( 3,3'"-dioctyl- 2,2':5',2 ":5",2'"-quaterthiophene)dicarboxamide(DNC1sDOc4T), were designed and synthesized. Whereas DNC183T did not form gels with organic solvents, DNCnDOc3T(n = 8, 16, 18) and DNC18DOc4T were found to form gels with certain organic solvents. These are the first examples of low molecular-weight organic gels containing an oligothiophene moiety. It is of intest to note that while DNC8DOc3T forms opaque gels with alcohols,e.g. ethanol and isopropanol, DNC16DOc3T, DNC18DOc3T and DNC18DOc4Tform transparent gels with hydrocarbon solvents such as heptane, octane, undecane, and others. It is shown that the intermolecular hydrogen bonding and intermolecular interactions between the long alkyl chain in the N-alkylcarboxamide group as well as the incorporation of an alkyl group at the β-position of the thiophene ring play an important role for the formation of gels. The optical micrographs of gels and the SEM images of xerogels showed three-dimensional networks of fibrous bundle structures.DNC18DOc4T gels was found to exhibit a reversible clear color change on electrochemical oxidation and reduction. Thus, low molecular-weight organic gels function as a new

  9. Development and characterization of mucoadhesive in situ nasal gel of midazolam prepared with Ficus carica mucilage.

    Science.gov (United States)

    Basu, Shyamoshree; Bandyopadhyay, Amal Kumar

    2010-09-01

    The objective of the present study was to prepare mucoadhesive in situ nasal gels with mucilage isolated from fig fruits (Ficus carica, family: Moraceae) containing midazolam hydrochloride. Nasal gels of midazolam were prepared using three different concentrations (0.5%, 1.0% and 1.5% w/v) of F. carica mucilage (FCM) and synthetic polymers (hydroxypropylmethyl cellulose and Carbopol 934). Evaluation of FCM showed that it was as safe as the synthetic polymers for nasal administration. In situ gels were prepared with mixture Pluronic F127 and mucoadhesive agents. Evaluation of the prepared gels was carried out, including determination of viscosity, texture profile analysis and mucoadhesive strength. In vitro drug permeation study was conducted with the gels prepared with and without permeation enhancer (0.5% w/v sodium taurocholate) using excised goat nasal mucosa. In vitro permeation profiles were evaluated, and histological study of nasal mucosae before and after permeation study was also conducted to determine histological change, if any. In vivo experiments conducted in rabbits further confirmed that in situ nasal gels provided better bioavailability of midazolam than the gels prepared from synthetic mucoadhesive polymers. It was observed that the nasal gel containing 0.5% FCM and 0.5% sodium taurocholate exhibited appropriate rheological, mechanical and mucoadhesive properties and showed better drug release profiles. Moreover, this formulation produced no damage to the nasal mucosa that was used for the permeation study, and absolute bioavailability was also higher compared to gels prepared from synthetic polymers.

  10. Polymer fractionation

    Energy Technology Data Exchange (ETDEWEB)

    Hadermann, A. F.

    1985-04-09

    Soluble polymers are fractionated according to molecular weight by cryogenically comminuting the polymer and introducing the polymer particles, while still in the active state induced by cryogenic grinding, into a liquid having a solvent power selected to produce a coacervate fraction containing high molecular weight polymer species and a dilute polymer solution containing lower molecular weight polymer species. The coacervate may be physically separated from the solution and finds use in the production of antimisting jet fuels and the like.

  11. The Chemistry and Applications of π-Gels

    Science.gov (United States)

    Ghosh, Samrat; Praveen, Vakayil K.; Ajayaghosh, Ayyappanpillai

    2016-07-01

    π-Gels are a promising class of functional soft materials formed out of short π-conjugated molecules. By utilizing the chemistry of noncovalent interactions, researchers have created a wide range of π-gels that are composed of supramolecular polymers. During the last two decades, supramolecular gel chemistry has been pursued with the hope of developing new materials for applications in, for example, organic electronics, energy harvesting, sensing, and imaging. The high expectations for π-gels were centered mainly around their electronic properties, such as tunable emission, energy transfer, electron transfer, charge transport, and electrical conductivity; such properties are amenable to modulation through size and shape control of molecular assemblies. Although a large number of exciting publications have appeared, a major technological breakthrough is yet to be realized. In this review, we analyze the recent advancements in the area of functional π-gels and their scope in future applications.

  12. Processing and characterization of Aloe vera gel for hydrogel preparation

    International Nuclear Information System (INIS)

    This work describes the processing and characterization of Aloe vera gel for the preparation of hydrogels through gamma radiation from polymers and natural products in order to be used in biomedical applications. Processing was carried out immersing slices of aloe in distilled water for phenolic compound extraction. Through UV-VIS spectroscopy, 48 hours was determined as the optimal soaking time, at which organoleptic characteristics of the gel as well as its pH were acceptable. An increase of pH was observed on the gel that was stored at room temperature. The non processed gel showed a pink coloration. Results of gel yield values were not high. Microbiological tests showed a high bioburden. (author)

  13. GelTouch

    DEFF Research Database (Denmark)

    Miruchna, Viktor; Walter, Robert; Lindlbauer, David;

    2015-01-01

    We present GelTouch, a gel-based layer that can selectively transition between soft and stiff to provide tactile multi-touch feedback. It is flexible, transparent when not activated, and contains no mechanical, electromagnetic, or hydraulic components, resulting in a compact form factor (a 2mm thin...... touchscreen layer for our prototype). The activated areas can be morphed freely and continuously, without being limited to fixed, predefined shapes. GelTouch consists of a poly(N-isopropylacrylamide) gel layer which alters its viscoelasticity when activated by applying heat (>32 C). We present three different...... a tablet with 6x4 tactile areas, enabling a tactile numpad, slider, and thumbstick. We show that the gel is up to 25 times stiffer when activated and that users detect tactile features reliably (94.8%)....

  14. User`s guide and documentation manual for ``PC-Gel`` simulator

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Ming-Ming; Gao, Hong W.

    1993-10-01

    PC-GEL is a three-dimensional, three-phase (oil, water, and gas) permeability modification simulator developed by incorporating an in-situ gelation model into a black oil simulator (BOAST) for personal computer application. The features included in the simulator are: transport of each chemical species of the polymer/crosslinker system in porous media, gelation reaction kinetics of the polymer with crosslinking agents, rheology of the polymer and gel, inaccessible pore volume to macromolecules, adsorption of chemical species on rock surfaces, retention of gel on the rock matrix, and permeability reduction caused by the adsorption of polymer and gel. The in-situ gelation model and simulator were validated against data reported in the literature. The simulator PC-GEL is useful for simulating and optimizing any combination of primary production, waterflooding, polymer flooding, and permeability modification treatments. A general background of permeability modification using crosslinked polymer gels is given in Section I and the governing equations, mechanisms, and numerical solutions of PC-GEL are given in Section II. Steps for preparing an input data file with reservoir and gel-chemical transport data, and recurrent data are described in Sections III and IV, respectively. Example data inputs are enclosed after explanations of each input line to help the user prepare data files. Major items of the output files are reviewed in Section V. Finally, three sample problems for running PC-GEL are described in Section VI, and input files and part of the output files of these problems are listed in the appendices. For the user`s reference a copy of the source code of PC-GEL computer program is attached in Appendix A.

  15. Development and characterization of a family of shape memory, biocompatible, degradable, porous (co)-polyurethanes via sol-gel chemistry

    Science.gov (United States)

    Lippincott, Hugh Walker

    shape or the shape memory force with no return from a tensile test. Characterization of the scaffold's compressive shape memory (percent strain recovery under stress) offers a clinical user design data for interactions with body tissue. Standard tensile shape memory ratios were translated to the compressive stress, strain, and temperature cycles used to characterize the shape-memory abilities of the two sol-gel families tested. The advantage of a thermoset polymer's ability to achieve 100% shape memory repeatability is demonstrated. This scaffold's compressive shape memory actuation energy density was above 6.0 KJ/m 3 over a range of recovery strains from 5% to 12%.

  16. Formulating gels for decreased mucociliary transport using rheologic properties: Polyacrylic acids

    OpenAIRE

    Shah, Ankur J; Donovan, Maureen D.

    2007-01-01

    The purpose of these studies was to identify the rheologic properties of polyacrylic acid gels necessary for optimal reductions in mucociliary clearance. The mucociliary transport of 2 bioadhesive polyacrylic acid polymers, polycarbophil and carbopol, was assessed in vitro by measuring their clerance rates across explants of ciliated bovine tracheal tissue. The viscoelastic properties of polymer gels were measured in the presence of mucus using controlled stress rheometry. Combinations of app...

  17. DNA DAMAGE QUANTITATION BY ALKALINE GEL ELECTROPHORESIS.

    Energy Technology Data Exchange (ETDEWEB)

    SUTHERLAND,B.M.; BENNETT,P.V.; SUTHERLAND, J.C.

    2004-03-24

    Physical and chemical agents in the environment, those used in clinical applications, or encountered during recreational exposures to sunlight, induce damages in DNA. Understanding the biological impact of these agents requires quantitation of the levels of such damages in laboratory test systems as well as in field or clinical samples. Alkaline gel electrophoresis provides a sensitive (down to {approx} a few lesions/5Mb), rapid method of direct quantitation of a wide variety of DNA damages in nanogram quantities of non-radioactive DNAs from laboratory, field, or clinical specimens, including higher plants and animals. This method stems from velocity sedimentation studies of DNA populations, and from the simple methods of agarose gel electrophoresis. Our laboratories have developed quantitative agarose gel methods, analytical descriptions of DNA migration during electrophoresis on agarose gels (1-6), and electronic imaging for accurate determinations of DNA mass (7-9). Although all these components improve sensitivity and throughput of large numbers of samples (7,8,10), a simple version using only standard molecular biology equipment allows routine analysis of DNA damages at moderate frequencies. We present here a description of the methods, as well as a brief description of the underlying principles, required for a simplified approach to quantitation of DNA damages by alkaline gel electrophoresis.

  18. Comparative clinical and psychosocial benefits of tooth bleaching: different light activation of a 38% peroxide gel in a preliminary case-control study.

    Science.gov (United States)

    Calderini, Angelo; Sciara, Simona; Semeria, Chiara; Pantaleo, Giuseppe; Polizzi, Elisabetta

    2016-08-01

    Tooth bleaching is a widespread dental treatment with important psychosocial antecedents and outcomes involved. In the activation of in-office bleaching agents, a selective light radiation, that is, a diode laser seems to be a positive choice to decrease the time of bleaching without surface modification and with no residual tooth sensitivity for maximum effect and minimal clinical and psychological side effects. PMID:27525071

  19. Effect of local application of tea tree (Melaleuca alternifolia) oil gel on long pentraxin level used as an adjunctive treatment of chronic periodontitis: A randomized controlled clinical study

    OpenAIRE

    Elgendy, Enas Ahmed; Ali, Shereen Abdel-Moula; Zineldeen, Doaa Hussien

    2013-01-01

    Background: Conventional non-surgical periodontal therapy has been proven to be an effective treatment for patients with chronic periodontitis. Tea tree oil (TTO) can be used as adjunct to conventional periodontal therapy in patient with chronic periodontitis. The aim of this study was to evaluate the effectiveness of adjunctive treatment of TTO on the clinical parameters and the level of pentraxin-3 (PTX3) in chronic periodontitis. Materials and Methods: A total of 40 patients with moderate ...

  20. Topical delivery of clobetasol propionate loaded microemulsion based gel for effective treatment of vitiligo--part II: rheological characterization and in vivo assessment through dermatopharmacokinetic and pilot clinical studies.

    Science.gov (United States)

    Patel, Hetal K; Barot, Bhavesh S; Parejiya, Punit B; Shelat, Pragna K; Shukla, Arunkumar

    2014-07-01

    Vitiligo is a non contagious acquired pigmentation disorder with limited treatment possibilities. Clobetasol propionate (CP) is the drug-of-choice for vitiligo which suppresses the immune system by reducing immunoglobulin action and causes the restoration of melanocytes leading to repigmentation of skin. However, despite being effective, its low and variable bioavailability prompt for development of novel carrier that could effectively target CP to site of action without producing undesirable side-effects. Low solubility of CP in subsequent poor in vivo bioavailability was overcome by formulating microemulsion based gel of CP (MBC) which would enhance the percutaneous transport of CP into and across the skin barrier. Comprehensive characterization of MBC was carried out for viscosity, gel strength and rheological behavior. In vitro studies revealed much higher drug release, skin penetration and enhanced skin accumulation as compared to control (Cream of CP). In vitro and in vivo occlusion studies demonstrated similar occlusiveness for MBC and control. MBC exhibited 3.16 times higher stratum corneum CP levels compared to control. Visualization of cutaneous uptake in vivo using laser scanning microscopy confirmed targeting of CP to epidermis and dermis. Dermatopharmacokinetic studies of MBC showed enhanced drug deposition of CP in skin layers. MBC was assessed for in vivo efficacy by single blind randomized pilot clinical study. The efficacy was assessed by vitiligo area scoring index (VASI) method. After completion of trial, repigmentation of vitiligo patches in patients were evaluated and scored. MBC was superior in terms of faster repigmentation and efficacy when compared with control (p valuevitiligo patients.

  1. Fabrication and characterization of a foamed polylactic acid (PLA)/ thermoplastic polyurethane (TPU) shape memory polymer (SMP) blend for biomedical and clinical applications

    Science.gov (United States)

    Song, Janice J.; Srivastava, Ijya; Kowalski, Jennifer; Naguib, Hani E.

    2014-03-01

    Shape memory polymers (SMP) are a class of stimuli-responsive materials that are able to respond to external stimulus such as heat by altering their shape. Bio-compatible SMPs have a number of advantages over static materials and are being studied extensively for biomedical and clinical applications (such as tissue stents and scaffolds). A previous study has demonstrated that the bio-compatible polymer blend of polylactic acid (PLA)/ thermoplastic polyurethane (TPU) (50/50 and 70/30) exhibit good shape memory properties. In this study, the mechanical and thermo-mechanical (shape memory) properties of TPU/PLA SMP blends were characterized; the compositions studied were 80/20, 65/35, and 50/50 TPU/PLA. In addition, porous TPU/PLA SMP blends were fabricated with a gas-foaming technique; and the morphology of the porous structure of these SMPs foams were characterized with scanning electron microscopy (SEM). The TPU/PLA bio-compatible SMP blend was fabricated with melt-blending and compression molding. The glass transition temperature (Tg) of the SMP blends was determined with a differential scanning calorimeter (DSC). The mechanical properties studied were the stress-strain behavior, tensile strength, and elastic modulus; and the thermomechanical (or shape memory) properties studied were the shape fixity rate (Rf), shape recovery rate (Rr), response time, and the effect of recovery temperature on Rr. The porous 80/20 PLA/TPU SMP blend was found to have the highest tensile strength, toughness and percentage extension, as well as the lowest density and uniform pore structure in the micron and submicron scale. The porous 80/20 TPU/PLA SMP blend may be further developed for specific biomedical and clinical applications where a combination of tensile strength, toughness, and low density are required.

  2. Biodegradable Polymers

    Directory of Open Access Journals (Sweden)

    Isabelle Vroman

    2009-04-01

    Full Text Available Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources or from biological resources (renewable resources. In general natural polymers offer fewer advantages than synthetic polymers. The following review presents an overview of the different biodegradable polymers that are currently being used and their properties, as well as new developments in their synthesis and applications.

  3. Polymer electronics

    CERN Document Server

    Hsin-Fei, Meng

    2013-01-01

    Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

  4. Rehabilitation of a patient with amelogenesis imperfecta using porcelain veneers and CAD/CAM polymer restorations: A clinical report.

    Science.gov (United States)

    Saeidi Pour, Reza; Edelhoff, Daniel; Prandtner, Otto; Liebermann, Anja

    2015-01-01

    The complete dental rehabilitation of patients with a vertical dimension loss (VDL) caused by structural enamel deficits associated with amelogenesis imperfecta (AI) represents a difficult challenge for restorative teams. Accurate analysis and treatment planning that includes esthetic and functional evaluations and adequate material selection are important prerequisites for successful results. Long-term provisional restorations play an important role in exploring and elucidating the patients' esthetic demands and functional needs. Restorative treatment options can vary from requiring only oral hygiene instructions to extensive dental restorations that include composite fillings, ceramic veneers, metal-ceramic, or all-ceramic crowns. This case report describes a full-mouth rehabilitation of a patient with amelogenesis imperfecta including the case planning, bite replacement, preparation, and restoration setting steps with an experimental CAD/CAM polymer and porcelain veneers. PMID:26345104

  5. Selective interaction of lansoprazole and astemizole with tau polymers: potential new clinical use in diagnosis of Alzheimer's disease.

    Science.gov (United States)

    Rojo, Leonel E; Alzate-Morales, Jans; Saavedra, Iván N; Davies, Peter; Maccioni, Ricardo B

    2010-01-01

    We describe the interactions of two benzimidazole derivatives, astemizole (AST) and lansoprazole (LNS), with anomalous aggregates of tau protein (neurofibrillary tangles). Interestingly, these compounds, with important medical applications in the treatment of allergies and gastrointestinal disorders respectively, specifically bind to aggregated variants of tau protein and to paired helical filaments isolated from brains of Alzheimer's disease (AD) patients. These ligands appear to be a powerful tool to tag brain-isolated tau-aggregates and heparin-induced polymers of recombinant tau. The interactions of AST and LNS with tau aggregates were assessed by classical radioligand assays, surface plasmon resonance, and bioinformatic approaches. The affinity of AST and LNS for tau aggregates was comparatively higher than that for amyloid-beta polymers according to our data. This is relevant since senile plaques are also abundant but are not pathognomonic in AD patients. Immunochemical studies on paired helical filaments from brains of AD patients and surface plasmon resonance studies confirm these findings. The capacity of these drugs to penetrate the blood-brain barrier was evaluated: i) in vitro by parallel artificial membrane permeability assay followed by experimental Log P determinations; and ii) in vivo by pharmacokinetic studies comparing distribution profiles in blood and brain of mice using HPLC/UV. Importantly, our studies indicate that the brain/blood concentration ratios for these compounds were suitable for their use as PET radiotracers. Since neurofibrillary tangles are positively correlated with cognitive impairment, we concluded that LNS and AST have a great potential in PET neuroimaing for in vivo early detection of AD and in reducing the formation of neurofibrillary tangles. PMID:20110603

  6. Structure and Conductivity of Semiconducting Polymer Hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Rachel C.; Ferreira, Amy S.; Aguirre, Jordan C.; Kilbride, Daniel; Toso, Daniel B.; Mayoral, Kenny; Zhou, Z. Hong; Kopidakis, Nikos; Rubin, Yves; Schwartz, Benjamin J.; Mason, Thomas G.; Tolbert, Sarah H.

    2016-07-07

    Poly(fluorene-alt-thiophene) (PFT) is a conjugated polyelectrolyte that self-assembles into rod-like micelles in water, with the conjugated polymer backbone running along the length of the micelle. At modest concentrations (-10 mg/mL in aqueous solutions), PFT forms hydrogels, and this work focuses on understanding the structure and intermolecular interactions in those gel networks. The network structure can be directly visualized using cryo electron microscopy. Oscillatory rheology studies further tell us about connectivity within the gel network, and the data are consistent with a picture where polymer chains bridge between micelles to hold the network together. Addition of tetrahydrofuran (THF) to the gels breaks those connections, but once the THF is removed, the gel becomes stronger than it was before, presumably due to the creation of a more interconnected nanoscale architecture. Small polymer oligomers can also passivate the bridging polymer chains, breaking connections between micelles and dramatically weakening the hydrogel network. Fits to solution-phase small-angle X-ray scattering data using a Dammin bead model support the hypothesis of a bridging connection between PFT micelles, even in dilute aqueous solutions. Finally, time-resolved microwave conductivity measurements on dried samples show an increase in carrier mobility after THF annealing of the PFT gel, likely due to increased connectivity within the polymer network.

  7. Two new insoluble polymer composites for the treatment of LLW: 1. polypyrrole doped by UO22+ complexing polyanions 2. UO22+ complexing sol-gel based composites. Stability constants. Leaching tests, alpha and gamma irradiation

    International Nuclear Information System (INIS)

    In a previous work, we have demonstrated that polyanions like polyacrylamidoglycolic acid (PAAG) and polyacrylamidomethylpropanesulfonic acid (PAMPS) are capable to complex UO22+ ions. Unless they are crosslinked, these polyanions/UO22+ complexes are soluble when submitted to dynamic leaching tests in a Soxhlet extractor. Considering the feasibility of a new process for the storage or for the concentration of low level activity liquid wastes (LLW), we had to strongly enhance the insolubility of these complexes. We have developed two original insolubilization ways, as compared to the crosslinking of the polymer

  8. Influence of a Point-to-Plane DC Negative Corona Discharge on Gel Surfaces

    OpenAIRE

    Y. Klenko; Scholtz, V

    2008-01-01

    Point-to-plane corona discharge is widely used for modifying polymer surfaces for biomedical applications and for sterilization and decontamination. This paper focuses on an experimental investigation of the influence of the single-point and multi-point corona discharge electric field on gel surface. Three types of gelatinous agar were used as the gel medium: blood agar, nutrient agar and Endo agar. The gel surface modification was studied for various time periods and discharge currents. 

  9. Influence of a Point-to-Plane DC Negative Corona Discharge on Gel Surfaces

    Directory of Open Access Journals (Sweden)

    Y. Klenko

    2008-01-01

    Full Text Available Point-to-plane corona discharge is widely used for modifying polymer surfaces for biomedical applications and for sterilization and decontamination. This paper focuses on an experimental investigation of the influence of the single-point and multi-point corona discharge electric field on gel surface. Three types of gelatinous agar were used as the gel medium: blood agar, nutrient agar and Endo agar. The gel surface modification was studied for various time periods and discharge currents. 

  10. Formulation and evaluation of topical polyherbal antiacne gels containing Garcinia mangostana and Aloe vera

    OpenAIRE

    Gowda Bhaskar; Shariff Arshia; S.R.B Priyadarshini

    2009-01-01

    The objective of the study was to develop a topical poly herbal gel for the treatment of mild acne vulgaris. Aqueous extracts of Garcinia mangostana and Aloe vera were formulated in an aqueous based carbopol-934(1%w/w) gel system. Preformulation studies on solubility, partition co-efficient, MIC, MBC were determined along with compatibility studies using a validated HPLC method. Six formulations of the gel were prepared by varying the proportions of polymers and evaluated for their physicoche...

  11. Preparation of chitosan gel

    Directory of Open Access Journals (Sweden)

    Lagerge S.

    2012-06-01

    Full Text Available Aerogel conditioning of the chitosan makes it possible to prepare porous solids of significant specific surface. The increase in the chitosan concentration or the degree of acetylation decreases the specific surface of the synthesized chitosan gel. Whereas drying with supercritical CO2 more effectively makes it possible to preserve the volume of the spheres of gel and to have a more significant specific surface in comparison with evaporative drying.

  12. Conformance Improvement Using Gels

    Energy Technology Data Exchange (ETDEWEB)

    Seright, Randall S.; Schrader; II Hagstrom, John; Wang, Ying; Al-Dahfeeri, Abdullah; Marin, Amaury

    2002-09-26

    This research project had two objectives. The first objective was to identify gel compositions and conditions that substantially reduce flow through fractures that allow direct channeling between wells, while leaving secondary fractures open so that high fluid injection and production rates can be maintained. The second objective was to optimize treatments in fractured production wells, where the gel must reduce permeability to water much more than that to oil.

  13. Crystallization from Gels

    Science.gov (United States)

    Narayana Kalkura, S.; Natarajan, Subramanian

    Among the various crystallization techniques, crystallization in gels has found wide applications in the fields of biomineralization and macromolecular crystallization in addition to crystallizing materials having nonlinear optical, ferroelectric, ferromagnetic, and other properties. Furthermore, by using this method it is possible to grow single crystals with very high perfection that are difficult to grow by other techniques. The gel method of crystallization provides an ideal technique to study crystal deposition diseases, which could lead to better understanding of their etiology. This chapter focuses on crystallization in gels of compounds that are responsible for crystal deposition diseases. The introduction is followed by a description of the various gels used, the mechanism of gelling, and the fascinating phenomenon of Liesegang ring formation, along with various gel growth techniques. The importance and scope of study on crystal deposition diseases and the need for crystal growth experiments using gel media are stressed. The various crystal deposition diseases, viz. (1) urolithiasis, (2) gout or arthritis, (3) cholelithiasis and atherosclerosis, and (4) pancreatitis and details regarding the constituents of the crystal deposits responsible for the pathological mineralization are discussed. Brief accounts of the theories of the formation of urinary stones and gallstones and the role of trace elements in urinary stone formation are also given. The crystallization in gels of (1) the urinary stone constituents, viz. calcium oxalate, calcium phosphates, uric acid, cystine, etc., (2) the constituents of the gallstones, viz. cholesterol, calcium carbonate, etc., (3) the major constituent of the pancreatic calculi, viz., calcium carbonate, and (4) cholic acid, a steroidal hormone are presented. The effect of various organic and inorganic ions, trace elements, and extracts from cereals, herbs, and fruits on the crystallization of major urinary stone and gallstone

  14. Structure and electrical properties of Na0.5Bi0.5TiO3 ferroelectric thick films derived from a polymer modified sol-gel method.

    Science.gov (United States)

    Ji, Hongfen; Ren, Wei; Wang, Lingyan; Shi, Peng; Chen, Xiaofeng; Wu, Xiaoqing; Yao, Xi; Lau, Sien-Ting; Zhou, Qifa; Shung, K Kirk

    2011-10-01

    Lead-free NaBi(0.5)TiO(3) (NBT) ferroelectric thick films were prepared by a poly(vinylpyrrolidone) (PVP) modified sol-gel method. The NBT thick films annealed from 500°C to 750°C exhibit a perovskite structure. The relationship between annealing temperature, thickness, and electrical properties of the thick films has been investigated. The dielectric constants and remnant polarizations of the thick films increase with annealing temperature. The electrical properties of the NBT films show strong thickness dependence. As thickness increases from 1.0 to 4.8 μm, the dielectric constant of the NBT films increases from 620 to 848, whereas the dielectric loss is nearly independent of the thickness. The remnant polarization of the NBT thick films also increases with increasing thickness. The leakage current density first decreases and then increases with film thickness. PMID:21989868

  15. Hydrogen production via urea electrolysis using a gel electrolyte

    Science.gov (United States)

    King, Rebecca L.; Botte, Gerardine G.

    2011-03-01

    A technology was demonstrated for the production of hydrogen and other valuable products (nitrogen and clean water) through the electrochemical oxidation of urea in alkaline media. In addition, this process remediates toxic nitrates and prevents gaseous ammonia emissions. Improvements to urea electrolysis were made through replacement of aqueous KOH electrolyte with a poly(acrylic acid) gel electrolyte. A small volume of poly(acrylic acid) gel electrolyte was used to accomplish the electrochemical oxidation of urea improving on the previous requirement for large amounts of aqueous potassium hydroxide. The effect of gel composition was investigated by varying polymer content and KOH concentrations within the polymer matrix in order to determine which is the most advantageous for the electrochemical oxidation of urea and production of hydrogen.

  16. Optimized MR imaging for polyacrylamide gel dosimetry

    International Nuclear Information System (INIS)

    Polyacrylamide gels are a powerful tool to measure radiation dose by quantifying the NMR T2 relaxation times of the irradiated gel. The exploitation of these radiation sensitive gels in clinical radiotherapy requires accurate mapping of T2 values. This paper describes the optimization strategy used to identify accurate and practical methods of measuring the range of T2 values typical of gel dosimeters (140-700 ms). The MR imaging techniques used to measure T2 values and the choice of image acquisition parameters are described. Four sequences are compared and the results are analysed in terms of accuracy, signal-to-noise ratio and acquisition time. A multiple spin echo sequence was found to yield the most accurate results (98.9%). Single spin echo sequences, such as Hahn spin echo and EPI spin echo, were found to measure gel T2 values with an accuracy of 90.1%. This paper reports the importance of careful selection and optimization of the MR imaging sequences for accurate and reliable polyacrylamide gel dosimetry. (author)

  17. 夫西地酸乳膏联合阿达帕林凝胶治疗寻常痤疮的临床观察%Clinical Therapeutic Effect of Fusidic Acid Cream Combine Adapalene Gel for Acne Vulgaris

    Institute of Scientific and Technical Information of China (English)

    龙福泉; 王千秋

    2012-01-01

    Objective To evaluate the clinical efficacy and safety of 2% fusidic acid cream and 0. 1% adapalene gel in the treatment of mild and moderate acne vulgaris. Methods A total of 246 patients with mild to moderate ( Grade I - HI ) acne vulgaris were enrolled and randomly divided into 3 groups: 98 cases in treatment group which were treated by 2% fusidic acid cream combined with 0. 1% adapalene gel; 81 cases in control group A which were treated by 1% clindamyein phosphate gel combined with 0. 1% adapalene gel; 67 cases in control group B which were treated only by 0. 1% adapalene gel. All the patients recieved therapy for 8 weeks continuously and had been observed to evaluate the efficacy on the second, fourth and eighth week of treatment. Results On the eighth week of treatment, the total effective rate of treatment group was 93.88% , and there was a significant difference compared with the control group A( 81. 48% ,P =0.010) , meanwhile, the effective rate of treatment group in acne vulgaris with Grade HI was 93. 02% and there was also significant difference between these two groups( 69. 70% ,P =0. 007 ). After the treatment, there were 5 cases of recurrence in the treatment group and the recurrence rate was 5. 10% , however, it was much lower than that of two control groups. The group treated only by 0.1 % adapalene gel had poor effect and higher recurrence. All these 3 groups had not obvious side-effect during Ireatment. Conclusion It is an ideal therapy by using 2% fusidie acid cream combined with 0.1 % adapalene gel in the treatment of mild to moderate acne vulgaris with belter effect, lower recurrence rate and less side-effect.A 41-year old male with aplastic anemia history of 1 year, suffered pedicled wart on the praeputium for more than 4 months. Laboratory examination: platelet account 28 ×109/L, haematoglobin 90g/L. Diagnosis; con-dyloma acuminatum, aplastic anemia. Therapy; We applied ligature to the patient. The wart body was removed completely after 21

  18. Transfer printing of thermoreversible ion gels for flexible electronics.

    Science.gov (United States)

    Lee, Keun Hyung; Zhang, Sipei; Gu, Yuanyan; Lodge, Timothy P; Frisbie, C Daniel

    2013-10-01

    Thermally assisted transfer printing was employed to pattern thin films of high capacitance ion gels on polyimide, poly(ethylene terephthalate), and SiO2 substrates. The ion gels consisted of 20 wt % block copolymer poly(styrene-b-ethylene oxide-b-styrene and 80 wt % ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)amide. Patterning resolution was on the order of 10 μm. Importantly, ion gels containing the block polymer with short PS end blocks (3.4 kg/mol) could be transfer-printed because of thermoreversible gelation that enabled intimate gel-substrate contact at 100 °C, while gels with long PS blocks (11 kg/mol) were not printable at the same temperature due to poor wetting contact between the gel and substrates. By using printed ion gels as high-capacitance gate insulators, electrolyte-gated thin-film transistors were fabricated that operated at low voltages (<1 V) with high on/off current ratios (∼10(5)). Statistical analysis of carrier mobility, turn-on voltage, and on/off ratio for an array of printed transistors demonstrated the excellent reproducibility of the printing technique. The results show that transfer printing is an attractive route to pattern high-capacitance ion gels for flexible thin-film devices.

  19. Transfer printing of thermoreversible ion gels for flexible electronics.

    Science.gov (United States)

    Lee, Keun Hyung; Zhang, Sipei; Gu, Yuanyan; Lodge, Timothy P; Frisbie, C Daniel

    2013-10-01

    Thermally assisted transfer printing was employed to pattern thin films of high capacitance ion gels on polyimide, poly(ethylene terephthalate), and SiO2 substrates. The ion gels consisted of 20 wt % block copolymer poly(styrene-b-ethylene oxide-b-styrene and 80 wt % ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)amide. Patterning resolution was on the order of 10 μm. Importantly, ion gels containing the block polymer with short PS end blocks (3.4 kg/mol) could be transfer-printed because of thermoreversible gelation that enabled intimate gel-substrate contact at 100 °C, while gels with long PS blocks (11 kg/mol) were not printable at the same temperature due to poor wetting contact between the gel and substrates. By using printed ion gels as high-capacitance gate insulators, electrolyte-gated thin-film transistors were fabricated that operated at low voltages (<1 V) with high on/off current ratios (∼10(5)). Statistical analysis of carrier mobility, turn-on voltage, and on/off ratio for an array of printed transistors demonstrated the excellent reproducibility of the printing technique. The results show that transfer printing is an attractive route to pattern high-capacitance ion gels for flexible thin-film devices. PMID:24028461

  20. Clinical evaluation of EDTA gel in the curved root canal preparation%乙二胺四乙酸凝胶在弯曲根管预备中的应用效果评价

    Institute of Scientific and Technical Information of China (English)

    高洁; 吕锦

    2012-01-01

    Objective To evaluate the clinical performance of EDTA gel in the curved root canal preparation. Methods The teeth of 155 patients were randomly divided into three groups ( Group A, B and C) with 67,59 and 63 teeth, respectively. In addition to instrumentation with stainless steel K files and hand nickel-titanium files,teeth in group A were added with EDTA gel in their root canals to facilitate access of files. Then all the groups were either alternatively flushed with 0. 5% sodium hypochlorite and saline solution (Group A and B) or 3% hydrogen peroxide and saline solution (Group C). Difference in the root canal preparation,filling efficiency and interappointment flare-ups were evaluated. Results Group A, in which EDTA gel was applied, is significantly different from the others in the efficiency of preparation and filling quality. However,the occurrence of interappointment flare-ups does not significantly decrease. Conclusion EDTA gel helps to improve the efficiency and quality of curved root canal preparation.%目的 评价弯曲根管预备中应用乙二胺四乙酸(EDTA)凝胶的临床效果.方法 将155例患者的189颗患牙分为三组,A组67颗患牙行不锈钢K锉结合手用镍钛锉+EDTA凝胶根管预备,0.5%次氯酸钠及生理盐水交替冲洗;B组59颗患牙行不锈钢K锉结合手用镍钛锉根管预备,0.5%次氯酸钠及生理盐水交替冲洗;C组63颗患牙行不锈钢K锉结合手用镍钛锉根管预备,3%双氧水及生理盐水交替冲洗.评价各组间根管预备情况、根管充填效果及约诊间疼痛的差异.结果 A组在弯曲根管预备过程中预备时间及器械折断率均明显低于B、C两组,根管充填成功率高于B、C两组,差异均有统计学意义(P0.05).结论 在弯曲根管的预备过程中应用EDTA凝胶,能有效提高根管预备的效率及根管的预备质量.

  1. Dosimetry for synchrotron stereotactic radiotherapy: Monte Carlo simulations and radiosensitive gels; Dosimetrie pour la radiotherapie stereotaxique en rayonnement synchrotron: calculs Monte-Carlo et gels radiosensibles

    Energy Technology Data Exchange (ETDEWEB)

    Boudou, C

    2006-09-15

    High grade gliomas are extremely aggressive brain tumours. Specific techniques combining the presence of high atomic number elements within the tumour to an irradiation with a low x-rays (below 100 keV) beam from a synchrotron source were proposed. For the sake of clinical trials, the use of treatment planning system has to be foreseen as well as tailored dosimetry protocols. Objectives of this thesis work were (1) the development of a dose calculation tools based on Monte Carlo code for particles transport and (2) the implementation of an experimental method for the three dimensional verification of the dose delivered. The dosimetric tool is an interface between tomography images from patient or sample and the M.C.N.P.X. general purpose code. Besides, dose distributions were measured through a radiosensitive polymer gel, providing acceptable results compared to calculations.

  2. Synthesis, structure, and mechanical properties of silica nanocomposite polyrotaxane gels

    Science.gov (United States)

    Matsui, Daisuke; Mayumi, Koichi

    2015-01-01

    Summary A significantly soft and tough nanocomposite gel was realized by a novel network formed using cyclodextrin-based polyrotaxanes. Covalent bond formation between the cyclic components of polyrotaxanes and the surface of silica nanoparticles (15 nm diameter) resulted in an infinite network structure without direct bonds between the main chain polymer and the silica. Small-angle X-ray scattering revealed that the homogeneous distribution of silica nanoparticles in solution was maintained in the gel state. Such homogeneous nanocomposite gels were obtained with at least 30 wt % silica content, and the Young’s modulus increased with silica content. Gelation did not occur without silica. This suggests that the silica nanoparticles behave as cross-linkers. Viscoelastic measurements of the nanocomposite gels showed no stress relaxation regardless of the silica content for rubber theory. In addition, the composite gels were tough enough to completely maintain the network structure under 80% compression strain. These toughness and softness properties are attributable to both the characteristic sliding of polymer chains through the immobilized cyclodextrins on the silica nanoparticle and the entropic contribution of the cyclic components to the elasticity of the gels. PMID:26664642

  3. Responsive Gel-Gel Phase Transitions in Artificially Engineered Protein Hydrogels

    Science.gov (United States)

    Olsen, B. D.

    2012-02-01

    Artificially engineered protein hydrogels provide an attractive platform for biomedical materials due to their similarity to components of the native extracellular matrix. Engineering responsive transitions between shear-thinning and tough gel phases in these materials could potentially enable gels that are both shear-thinning and tough to be produced as novel injectable biomaterials. To engineer a gel with such transitions, a triblock copolymer with thermoresponsive polymer endblocks and an artificially engineered protein gel midblock is designed. Temperature is used to trigger a transition from a single network protein hydrogel phase to a double network phase with both protein and block copolymer networks present at different length scales. The thermodynamics of network formation and resulting structural changes are established using small-angle scattering, birefringence, and dynamic scanning calorimetry. The formation of the second network is shown to produce a large, nonlinear increase in the elastic modulus as well as enhancements in creep compliance and toughness. Although the gels show yielding behavior in both the single and double network regimes, a qualitative change in the deformation mechanism is observed due to the structural changes.

  4. Molecular engineering of polymer actuators for biomedical and industrial use

    Science.gov (United States)

    Banister, Mark; Eichorst, Rebecca; Gurr, Amy; Schweitzer, Georgette; Geronov, Yordan; Rao, Pavalli; McGrath, Dominic

    2012-04-01

    Five key materials engineering components and how each component impacted the working performance of a polymer actuator material are investigated. In our research we investigated the change of actuation performance that occurred with each change we made to the material. We investigated polymer crosslink density, polymer chain length, polymer gelation, type and density of reactive units, as well as the addition of binders to the polymer matrix. All five play a significant role and need to be addressed at the molecular level to optimize a polymer gel for use as a practical actuator material for biomedical and industrial use.

  5. Thermally reversible gels in electrophoresis. I - Matrix characterization

    Science.gov (United States)

    Righetti, Pier Giorgio; Snyder, Robert S.

    1988-01-01

    Two series of thermally reversible hydrogen-bonded gels have been characterized: (5 pct) PVA-(4 pct) PEG and (5 pct) PVA-(0.04 pct) borate gels. They both have extremely low melting points (16-17 C) and could be of potential interest for recovery of proteins after preparative electrophoresis. The PVA-borate gels can be exploited in the pH range 7-11 by progressively increasing the borate content in the pH interval 8 to 7 and concomitantly decreasing the borate levels in the pH zone 8 to 11. It is hypothesized that the low melting point of these gels is due to the fact that they are sparingly and sparsely hydrogen bonded along the PVA chain: on the average, 1 OH group out of 3 or 4 OH groups in the PVA polymer should be engaged in H-bond formation.

  6. Reproducibility study of normoxic polyacrylamide gel (nPAG) dosimeters

    International Nuclear Information System (INIS)

    In this study, the overall accuracy of normoxic polyacrylamide gel (nPAG) dosimeters is considered. Different badges of nPAG are fabricated, poured in containers of glass and Barex and irradiated with a 6MV square photon beam. The polymer gel dosimeters were read out using MRI. The overall reproducibility and accuracy of nPAG gel dosimeters was determined by comparison with depth-dose profiles acquired with a Pin Point ionization chamber. Additionally, the effect of the container wall on the depth-dose profile and the effect of temperature changes before and after irradiation on the R2-dose response have been investigated. The average standard deviation and maximum deviation between 8 gel-measured depth-dose profiles and a depth-dose profile measured with an ionization chamber amounted to 0.543 Gy (2.5%) and 2.579 Gy (11.7%) respectively.

  7. SUPER TOUGH GELS WITH A DOUBLE NETWORK STRUCTURE

    Institute of Scientific and Technical Information of China (English)

    Tasuku Nakajima; Takayuki Kurokawa; Hidemitsu Furukawa; Qiu Ming Yu; Yoshimi Tanaka; Yoshihito Osada; Jian Ping Gong

    2009-01-01

    Living tissues work with fantastic functions in soft and wet gel-like state. Thus,hydrogels have attracted much attention as excellent soft and wet materials,suitable for making artificial organs for medical treatments. However,conventional hydrogels are mechanically too weak for practical uses. We have created double network (DN) hydrogels with extremely high mechanical strength in order to overcome this problem. DN gels are interpenetrating network (IPN) hydrogels consisting of rigid polyelectrolyte and soft neutral polymer. Their excellent mechanical properties cannot be explained by the standard fracture theories. In this paper,we discuss about the toughening mechanism of DN gels in accordance with their characteristic behavior,such as large hysteresis and necking phenomenon. We also describe the results on tissue engineering application of DN gels.

  8. Directed percolation identified as equilibrium pre-transition towards non-equilibrium arrested gel states

    Science.gov (United States)

    Laurati, Marco; Capellmann, Ronja; Kohl, Matthias; Egelhaaf, Stefan; Schmiedeberg, Michael

    The macroscopic properties of gels arise from their slow dynamics and load bearing network structure, which are exploited by nature and in numerous industrial products. However, a link between these structural and dynamical properties has remained elusive. Here we present confocal microscopy exper- iments and simulations of gel-forming colloid-polymer mixtures with competing interactions. They reveal that gel formation is preceded by continuous and directed percolation. Both transitions lead to system spanning networks, but only directed percolation results in extremely slow dynamics, ageing and a shrinking of the gel that resembles syneresis. Therefore, dynamical arrest in gels is found to be linked to a structural transition, namely directed percolation, which is quantitatively associated with the mean number of bonded neighbours. Directed percolation is a universality class of transitions out of equilibrium, our study hence connects gel formation to a well-developed theoretical framework which now can be exploited to achieve a detailed understanding of arrested gels.

  9. Directed percolation identified as equilibrium pre-transition towards non-equilibrium arrested gel states

    Science.gov (United States)

    Kohl, M.; Capellmann, R. F.; Laurati, M.; Egelhaaf, S. U.; Schmiedeberg, M.

    2016-06-01

    The macroscopic properties of gels arise from their slow dynamics and load-bearing network structure, which are exploited by nature and in numerous industrial products. However, a link between these structural and dynamical properties has remained elusive. Here we present confocal microscopy experiments and simulations of gel-forming colloid-polymer mixtures. They reveal that gel formation is preceded by continuous and directed percolation. Both transitions lead to system-spanning networks, but only directed percolation results in extremely slow dynamics, ageing and a shrinking of the gel that resembles synaeresis. Therefore, dynamical arrest in gels is found to be linked to a structural transition, namely directed percolation, which is quantitatively associated with the mean number of bonded neighbours. Directed percolation denotes a universality class of transitions. Our study hence connects gel formation to a well-developed theoretical framework, which now can be exploited to achieve a detailed understanding of arrested gels.

  10. Preparation and characterisation of mucoadhesive nasal gel of venlafaxine hydrochloride for treatment of anxiety disorders

    Directory of Open Access Journals (Sweden)

    Shyamoshree Basu

    2012-01-01

    Full Text Available The aim of the present study is to prepare and evaluate mucoadhesive nasal gels of venlafaxine hydrochloride. Mucoadhesive nasal gels were prepared using polymers like carbopol 934 and sodium alginate and characterized in terms of viscosity, texture profile analysis, ex vivo drug permeation profiles and histopathological studies. The results show that values of viscosity, hardness and adhesiveness increase while those of cohesiveness decrease with corresponding increase in concentration of the polymers. Ex vivo drug permeation profiles showed that formulation containing 5% sodium alginate provided a better controlled release of the drug than the other formulations over a period of 12 h. Histopathological studies assured that gels containing different polymers did not produce any significant change in the nasal mucosae of goat even after 12 h permeation study. Mucoadhesive nasal gel of venlafaxine hydrochloride is a novel dosage form which delivers the drug directly into systemic circulation and provides controlled release of the drug.

  11. Cyclic polymers from alkynes

    Science.gov (United States)

    Roland, Christopher D.; Li, Hong; Abboud, Khalil A.; Wagener, Kenneth B.; Veige, Adam S.

    2016-08-01

    Cyclic polymers have dramatically different physical properties compared with those of their equivalent linear counterparts. However, the exploration of cyclic polymers is limited because of the inherent challenges associated with their synthesis. Conjugated linear polyacetylenes are important materials for electrical conductivity, paramagnetic susceptibility, optical nonlinearity, photoconductivity, gas permeability, liquid crystallinity and chain helicity. However, their cyclic analogues are unknown, and therefore the ability to examine how a cyclic topology influences their properties is currently not possible. We have solved this challenge and now report a tungsten catalyst supported by a tetraanionic pincer ligand that can rapidly polymerize alkynes to form conjugated macrocycles in high yield. The catalyst works by tethering the ends of the polymer to the metal centre to overcome the inherent entropic penalty of cyclization. Gel-permeation chromatography, dynamic and static light scattering, viscometry and chemical tests are all consistent with theoretical predictions and provide unambiguous confirmation of a cyclic topology. Access to a wide variety of new cyclic polymers is now possible by simply choosing the appropriate alkyne monomer.

  12. 2010 POLYMER PHYSICS - JUNE 27 - JULY 2, 2010

    Energy Technology Data Exchange (ETDEWEB)

    Karen Winey

    2010-07-02

    The 2010 Gordon Research Conference on Polymer Physics will provide outstanding lectures and discussions in this critical field that impacts every industrial sector from electronics to transportation to medicine to textiles to energy generation and storage. Fundamental topics range from mechanical properties of soft gels to new understanding in polymer crystallization to energy conversion and transmission to simulating polymer dynamics at the nanoscale. This international conference will feature 22 invited lectures, wherein the opening 10 minutes are specifically designed for a general polymer physics audience. In addition, poster sessions and informal activities provide ample opportunity to discuss the latest advances in polymer physics. The technical content of the meeting will include new twists on traditional polymer physics topics, recent advances in previously underrepresented topics, and emerging technologies enabled by polymer physics. Here is a partially listing of targeted topics: (1) electrically-active and light-responsive polymers and polymer-based materials used in energy conversion and storage; (2) polymers with hierarchical structures including supramolecular assemblies, ion-containing polymers, and self-assembled block polymers; (3) mechanical and rheological properties of soft materials, such as hydrogels, and of heterogeneous materials, particularly microphase separated polymers and polymer nanocomposites; and (4) crystallization of polymers in dilute solutions, polymer melts, and miscible polymer blends.

  13. Convective polymer assembly for the deposition of nanostructures and polymer thin films on immobilized particles

    Science.gov (United States)

    Richardson, Joseph J.; Björnmalm, Mattias; Gunawan, Sylvia T.; Guo, Junling; LiangPresent Address: Csiro Process Science; Engineering, Clayton, Victoria 3168, Australia, Kang; Tardy, Blaise; SekiguchiPresent Address: Graduate School Of Chemical Sciences; Engineering, Hokkaido University, Sapporo, Japan, Shota; Noi, Ka Fung; Cui, Jiwei; EjimaPresent Address: Institute Of Industrial Science, The University Of Tokyo, Tokyo, Japan, Hirotaka; Caruso, Frank

    2014-10-01

    We report the preparation of polymer particles via convective polymer assembly (CPA). Convection is used to move polymer solutions and cargo through an agarose gel that contains immobilized template particles. This method both coats and washes the particles in a process that is amenable to automation, and does not depend on passive diffusion or electrical currents, thus facilitating incorporation of fragile and nanoscale objects, such as liposomes and gold nanoparticles, into the thin polymer films. Template dissolution leads to the formation of stable polymer particles and capsules.We report the preparation of polymer particles via convective polymer assembly (CPA). Convection is used to move polymer solutions and cargo through an agarose gel that contains immobilized template particles. This method both coats and washes the particles in a process that is amenable to automation, and does not depend on passive diffusion or electrical currents, thus facilitating incorporation of fragile and nanoscale objects, such as liposomes and gold nanoparticles, into the thin polymer films. Template dissolution leads to the formation of stable polymer particles and capsules. Electronic supplementary information (ESI) available: Detailed experimental/instrumental information and supporting figures. See DOI: 10.1039/c4nr04348k

  14. Rubber-like poly(vinyl alcohol) gel

    International Nuclear Information System (INIS)

    Anomalous poly (vinyl alcohol) gel has been found in our laboratory since 1980. The gel is prepared by repeated freezing (or freeze-dehydration) of aqueous poly (vinyl alcohol). Experiments establish the fact that anomalous gel is never produced in the course of freezing, but during sustained thawing the gelation does occur. Moreover, it was found that the softening point of the gel increases at 37degC. It is assumed that crystal nuclei are generated on freezing, then on thawing, some of them grow to very fine crystals which act as polymer network-knots (cross-linking). Additional freezing provide other seeds, which grow similarly, and these are accumulated until rubber-like gel is produced. The gel was always water-resistant at 37degC, and the potassium permanganate consumption of the extracted water layer remained far below the official restricted value for medical materials. The gel can be sterilized with gamma-rays or chlorhexidine. Moreover, it satisfies the official standards of acute toxicity, pyrogen, intracutaneous reaction, hemolyzation, and intracorporeal implantation, respectively. Applications to adhesion-preventing membrane (for joint or pericardium), tamponade (for jaw defects), electrode (for electroretinogram or artificial inner ear), artificial denture base and phantoms for magnetic resonance imaging were examined. (author) 54 refs

  15. Rubber-like poly(vinyl alcohol) gel

    Energy Technology Data Exchange (ETDEWEB)

    Nambu, Masao (Nippon Oil Co. Ltd., Yokohama (Japan). Central Technical Research Lab.)

    1990-09-01

    Anomalous poly (vinyl alcohol) gel has been found in our laboratory since 1980. The gel is prepared by repeated freezing (or freeze-dehydration) of aqueous poly (vinyl alcohol). Experiments establish the fact that anomalous gel is never produced in the course of freezing, but during sustained thawing the gelation does occur. Moreover, it was found that the softening point of the gel increases at 37degC. It is assumed that crystal nuclei are generated on freezing, then on thawing, some of them grow to very fine crystals which act as polymer network-knots (cross-linking). Additional freezing provide other seeds, which grow similarly, and these are accumulated until rubber-like gel is produced. The gel was always water-resistant at 37degC, and the potassium permanganate consumption of the extracted water layer remained far below the official restricted value for medical materials. The gel can be sterilized with gamma-rays or chlorhexidine. Moreover, it satisfies the official standards of acute toxicity, pyrogen, intracutaneous reaction, hemolyzation, and intracorporeal implantation, respectively. Applications to adhesion-preventing membrane (for joint or pericardium), tamponade (for jaw defects), electrode (for electroretinogram or artificial inner ear), artificial denture base and phantoms for magnetic resonance imaging were examined. (author) 54 refs.

  16. Polymers for Protein Conjugation

    Directory of Open Access Journals (Sweden)

    Gianfranco Pasut

    2014-01-01

    Full Text Available Polyethylene glycol (PEG at the moment is considered the leading polymer for protein conjugation in view of its unique properties, as well as to its low toxicity in humans, qualities which have been confirmed by its extensive use in clinical practice. Other polymers that are safe, biodegradable and custom-designed have, nevertheless, also been investigated as potential candidates for protein conjugation. This review will focus on natural polymers and synthetic linear polymers that have been used for protein delivery and the results associated with their use. Genetic fusion approaches for the preparation of protein-polypeptide conjugates will be also reviewed and compared with the best known chemical conjugation ones.

  17. Photoaddressable Polymers

    Science.gov (United States)

    Bieringer, T.

    Polymers are the perfect materials for a variety of applications in almost every field of technical as well as human life. Because of their macromolecular architecture there are a lot of degrees of freedom in the synthesis of polymers. Owing to the change of their functional composition, they can be tailored even for quite difficult demands. Since a whole industry deals with the processing of polymers, cheap production lines have been developed for almost every polymer. This is the reason why not only the molecular composition but even the price of polymers has been optimized. Therefore these materials can be considered as encouraging components even in highly sophisticated areas of applications.

  18. Dosimetry for synchrotron stereotactic radiotherapy: Monte Carlo simulations and radiosensitive gels

    International Nuclear Information System (INIS)

    High grade gliomas are extremely aggressive brain tumours. Specific techniques combining the presence of high atomic number elements within the tumour to an irradiation with a low x-rays (below 100 keV) beam from a synchrotron source were proposed. For the sake of clinical trials, the use of treatment planning system has to be foreseen as well as tailored dosimetry protocols. Objectives of this thesis work were (1) the development of a dose calculation tools based on Monte Carlo code for particles transport and (2) the implementation of an experimental method for the three dimensional verification of the dose delivered. The dosimetric tool is an interface between tomography images from patient or sample and the M.C.N.P.X. general purpose code. Besides, dose distributions were measured through a radiosensitive polymer gel, providing acceptable results compared to calculations

  19. Comparative study on the effects of negatively-charged biopolymers on chitosan-based gels for the development of instantaneous gels

    International Nuclear Information System (INIS)

    Polymeric electrolytic complexes are solutions of charged/ionized chains. These solutions of positive and negative charge can be combined to make instantaneous networks bonded by electrostatic interactions, a gel network. These electrostatic interaction allows for easy application in injectable gels as the network can be temporarily distributed with the application of force and reformed on the relief of it. Possible applications for these injectable gels include drug delivery and wound-healing. κ-Carrageenan, dextran sulfate, alginate, and chitosan are polyelectrolytic biocompatible polymers which are widely studied and used for a variety of biomedical applications. Gel networks are made by combining a negatively-charged (κ-Carrageenan, dextran sulfate, or alginate) and positively charged (chitosan) solutions. The strong electrostatic interaction between the opposite charges from the gel network and the inherent biocompatibility of the polymers allow future biomedical applications. Quat 188-modified chitosan has additional sites for electrostatic bonding, can be dissolved in neutral, basic, and acidic pH, and has shown inherent antibacterial activity. The objectives of this study are the following: to formulate chitosan-based gels mixing solutions of chitosan with solutions of either κ-Carrageenan, dextran sulfate, or alginate, study the gelation of the gels as function of time and pH (4, 7, and 9) using UV-Vis, characterize the chitosan-based gels through DSC and DMA, characterize the physiological degradation of the chitosan-based gels, and compare results with those from Quat 188-modified chitosan-based gels. Polyelectrolytic solutions of chitosan and negatively-charged biopolymer of similar viscosities were mixed. It was determined from the UV-Vis spectroscopy of the chitosan-carrageenan gels under pH7 buffer that the increase of concentration by a factor of 5 for 0.006M-0.0095M and 1.25 for 0.0095M-0.0150M Chitosan-Carrageenan gels improved gelation by the

  20. Clinical observation of XuanJu detoxification gel in treatment of pregnancy gingivitis%玄菊解毒凝胶治疗妊娠期龈炎的临床观察

    Institute of Scientific and Technical Information of China (English)

    左渝陵; 李必泽; 赵娟

    2015-01-01

    Objective To evaluate the clinical effects of XuanJu detoxification gel in the treatment of pregnancy gingivitis . Methods Clinical data of 54 outpatients with pregnancy gingivitis in Affiliated Hospital of Chengdu University of TCM from Sep.2013 to Dec.2014 were selected.All patients were divided into group A , B and C according to different therapeutic methods with each group 18 cases.Group A:Washing affected teeth with 5 mL 1%H2O2 and 5 mL saline per teeth.group B:Besides the therapy above, applying XuanJu detoxification gel ( 0.5 mL per teeth ) .Group C: Using the gel only .The treatment indicators were observed: ①Sulcus bleeding index (SBI), plaque index (PI), periodontal pocket depth (PPD).②Nterleukin-1β(IL-1β), tumour necrosis factor-α( TNF-α) of gingival crevicular fluid .③ subjective symptoms , the improvement of halitosis .Results ① There were significant differences in PI , SBI, IL-1β, TNF-α, subjective symptoms, and the degree of halitosis before and after treatment of group B and group C (P<0.05).It found that only subjective symptoms had significant difference before and after treatment in group A.②All indicators in Group B were superior to group A and group C after treatment except PPD (P<0.05).Conclusion XuanJu detoxification gel combined with basic treatment has a good effect in the treatment of pregnancy gingivitis which has the advantages of simple prescription and superior dosage form .%目的:观察玄菊解毒凝胶治疗妊娠期龈炎临床疗效。方法选取2013年9月至2014年12月在成都中医药大学附属医院口腔科就诊的54例妊娠期龈炎患者的临床资料,根据治疗用药不同分为A、B、C 3组。1%双氧水5 mL/牙+生理盐水5 mL/牙冲洗治疗的患者纳入A组(18例);1%双氧水5 mL/牙+生理盐水5 mL/牙冲洗治疗基础上,联合玄菊解毒凝胶0.5 mL/牙治疗的患者纳入B组(18例);单纯玄菊解毒凝胶0.5 mL/

  1. Measurement of a PAGAT gel dosimeter by ultrasound computed tomography

    Science.gov (United States)

    Khoei, S.; Trapp, J. V.; Langton, C. M.

    2013-06-01

    In this work we used a 3D quantitative CT ultrasound imaging system to characterise polymer gel dosimeters. The system comprised of two identical 5 MHz 128 element phased-array ultrasound transducers co-axially aligned and submerged in water as a coupling agent. Rotational and translational movement of the gel dosimeter sample between the transducers were performed using a robotic arm. Ultrasound signals were generated and received using an Olympus Omniscan unit. Dose sensitivity of attenuation and time of flight ultrasonic parameters were assessed using this system.

  2. Colonization of Bordetella pertussis clinical isolates that differ by pulsed field gel electrophoresis types in the lungs of naïve mice or mice immunized with the whole-cell pertussis vaccine used in Poland.

    Science.gov (United States)

    Polak, Maciej; Zawadka, Monika; Mosiej, Ewa; Rabczenko, Daniel; Augustynowicz, Ewa; Guiso, Nicole; Lutyńska, Anna

    2015-04-01

    The goal of our study was to compare the elimination of Bordetella pertussis clinical isolates that differ according to pulsed field gel electrophoresis (PFGE), serotypes and genes encoding virulence factors from the lungs of naïve mice or mice immunized with commercial diphtheria-tetanus-whole-cell pertussis vaccine used in Poland. When a mixture of four isolates, given in equal proportions and harboring different PFGE profiles, serotypes, and alleles encoding virulence factors, was used to infect non-immunized mice, a single isolate, characterized by PFGE type IVγ, Fim2 phenotype and ptxA1-prn2-tcfA2-fim2-1-ptxP1-ptxC1-fim3-1 alleles, was found to be significantly predominant compared to the others. This PFGE profile is commonly found in B. pertussis isolates circulating in some European countries since the late 1990s, confirming its high fitness. The Polish commercial whole-cell pertussis vaccine induced an immunity effective at eliminating the B. pertussis isolates from the lungs. However, the elimination of the isolate harboring PFGE type C profile, Fim2,3 phenotype and ptxA1-prn1-tcfA2-fim2-1-ptxP1-ptxC1-fim3-1 alleles was delayed as compared to the others, suggesting phenotypic differences with the other isolates and vaccine strains. Nevertheless, the same isolate, when challenged into mice in the defined mixture of strains, lost the competition with the others, as measured by lung colonization efficiency. This PFGE profile represents 15 % of the isolates circulating in Poland between 2001 and 2012.

  3. Solvothermal synthesis of high molecular weight dithienogermole containing conjugated polymers

    Indian Academy of Sciences (India)

    Fei-Bao Zhang; Su-Fang Lv; Jiang-Xiong Jiang; Yong Ni

    2015-06-01

    Dithienogermole-diphthalimide, a new molecule, and dithienogermole-dithiadiazole alternate polymers were synthesized by the solvothermal method. Optical properties and molecular weight were investigated by UV–Vis absorption spectroscopy and Gel Permeation Chromatography. Compared with the results achieved by the previously reported normal heating method, these polymers reported here exhibited similar optical properties and possess higher molecular weight.

  4. Materials comprising polydienes and hydrophilic polymers and related methods

    Science.gov (United States)

    Mays, Jimmy W.; Deng, Suxiang; Mauritz, Kenneth A.; Hassan, Mohammad K.; Gido, Samuel P.

    2011-11-22

    Materials prepared from polydienes, such as poly(cyclohexadiene), and hydrophilic polymers, such as poly(alkylene oxide), are described. Methods of making the materials and their use in fuel cell membranes, batteries, breathable chemical-biological protective materials, and templates for sol-gel polymerization are also provided. The materials can be crosslinked and sulfonated, and can include copolymers and polymer blends.

  5. Polymer Molecular Weight Analysis by [Superscript 1]H NMR Spectroscopy

    Science.gov (United States)

    Izunobi, Josephat U.; Higginbotham, Clement L.

    2011-01-01

    The measurement and analysis of molecular weight and molecular weight distribution remain matters of fundamental importance for the characterization and physical properties of polymers. Gel permeation chromatography (GPC) is the most routinely used method for the molecular weight determination of polymers whereas matrix-assisted laser…

  6. Physics of Polymers under Nanoscopic Confinement: a Single Molecule Study

    NARCIS (Netherlands)

    Keshavarz, M.

    2016-01-01

    Physicist Masoumeh Keshavarz studied the thermal motion of a fluorescently labelled, individual “reporter” polymer molecule, surrounded and entangled by a gel of similar but unlabelled polymers. Owing to their extreme length and stiffness, it is possible to follow the shape and the motion of the rep

  7. Coupling the Alkaline-Surfactant-Polymer Technology and The Gelation Technology to Maximize Oil Production

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm Pitts; Jie Qi; Dan Wilson; Phil Dowling; David Stewart; Bill Jones

    2005-12-01

    Gelation technologies have been developed to provide more efficient vertical sweep efficiencies for flooding naturally fractured oil reservoirs or reservoirs with different sand lenses with high permeability contrast. The field proven alkaline-surfactant-polymer technology economically recovers 15% to 25% OOIP more crude oil than waterflooding from swept pore space of an oil reservoir. However, alkaline-surfactant-polymer technology is not amenable to naturally fractured reservoirs or reservoirs with high permeability contrast zones because much of injected solution bypasses target pore space containing oil. This work investigates whether combining these two technologies could broaden applicability of alkaline-surfactant-polymer flooding into these reservoirs. Fluid-fluid interaction with different gel chemical compositions and alkaline-surfactant-polymer solution with pH values ranging from 9.2 to 12.9 have been tested. Aluminum-polyacrylamide gels are not stable to alkaline-surfactant-polymer solutions at any pH. Chromium-polyacrylamide gels with polymer to chromium ion ratios of 25 or greater were stable to alkaline-surfactant-polymer solutions if solution pH was 10.6 or less. When the polymer to chromium ion was 15 or less, chromium-polyacrylamide gels were stable to alkaline-surfactant-polymer solutions with pH values up to 12.9. Chromium-xanthan gum gels were stable to alkaline-surfactant-polymer solutions with pH values of 12.9 at the polymer to chromium ion ratios tested. Silicate-polyacrylamide, resorcinol-formaldehyde, and sulfomethylated resorcinol-formaldehyde gels were also stable to alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Iron-polyacrylamide gels were immediately destroyed when contacted with any of the alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Gel solutions under dynamic conditions of linear corefloods showed similar stability to alkaline-surfactant-polymer solutions as in

  8. Effects of Shear Fracture on In-depth Profile Modification of Weak Gels

    Institute of Scientific and Technical Information of China (English)

    Li Xianjie; Song Xinwang; Yue Xiang'an; Hou Jirui; Fang Lichun; Zhang Huazhen

    2007-01-01

    Two sand packs were filled with fine glass beads and quartz sand respectively. The characteristics of crosslinked polymer flowing through the sand packs as well as the influence of shear fracture of porous media on the in-depth profile modification of the weak gel generated from the crosslinked polymer were investigated. The results indicated that under the dynamic condition crosslinking reaction happened in both sand packs,and the weak gels in these two cases became small gel particles after water flooding. The differences were:the dynamic gelation time in the quartz sand pack was longer than that in the glass bead pack. Residual resistance factor (FRR) caused by the weak gel in the quartz sand pack was smaller than that in the glass bead pack. The weak gel became gel particles after being scoured by subsequent flood water. A weak gel with uniform apparent viscosity and sealing characteristics was generated in every part of the glass bead pack,which could not only move deeply into the sand pack but also seal the high capacity channels again when it reached the deep part. The weak gel performed in-depth profile modification in the glass bead pack,while in the quartz sand pack,the weak gel was concentrated with 100 cm from the entrance of the sand pack. When propelled by the subsequent flood water,the weak gel could move towards the deep part of the sand pack but then became tiny gel particles and could not effectively seal the high capacity channels there. The in-depth profile modification of the weak gel was very weak in the quartz sand pack. It was the shear fracture of porous media that mainly affected the properties and weakened the in-depth profile modification of the weak gel.

  9. Performance enhancement of phosphoric acid fuel cell using phosphosilicate gel based electrolyte

    Institute of Scientific and Technical Information of China (English)

    Kajari Kargupta; Swati Saha; Dipali Banerjee; Mrinal Seal; Saibal Ganguly

    2012-01-01

    Replacement of phosphoric acid electrolyte by phosphosilicate gel based electrolytes is proposed for performance enhancement of phosphoric acid fuel cell (PAFG).Phosphosilicate gel in paste form and in powder form is synthesized from tetraethoxysilane and orthophosphoric acid using sol-gel method for two different P/Si ratio of 5 and 1.5 respectively.Replacement of phosphoric acid electrolyte by phosphosilicate gel paste enhances the peak power generation of the fuel cell by 133% at 120 ℃ cell temperature; increases the voltage generation in the ohmic regime and extends the maximum possible load current.Polyinyl alcohol (PVA) is used to bind the phosphosilicate gel powder and to form the hybrid crosslinked gel polymer electrolyte membrane.Soaking the membrane with phosphoric acid solution,instead of that with water improves the proton conductivity of the membrane,enhances the voltage and power generation by the fuel cell and extends the maximum possible operating temperature.At lower operating temperature of 70 ℃,peak power produced by phosphosilicate gel polymer electrolyte membrane fuel cell ( PGMFC ) is increased by 40% compared to that generated by phosphoric acid fuel cell ( PAFC ).However,the performance of composite membrane diminishes as the cell temperature increases.Thus phosphosilicate gel in paste form is found to be a good alternative of phosphoric acid electrolyte at medium operating temperature range while phosphosilicate gel-PVA composite offers performance enhancement at low operating temperatures.

  10. COUPLING THE ALKALINE-SURFACTANT-POLYMER TECHNOLOGY AND THE GELATION TECHNOLOGY TO MAXIMIZE OIL PRODUCTION

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm Pitts; Jie Qui; Dan Wilson; Phil Dowling

    2004-05-01

    Gelation technologies have been developed to provide more efficient vertical sweep efficiencies for flooding naturally fractured oil reservoirs or more efficient areal sweep efficiency those with high permeability contrast ''thief zones''. The field proven alkaline-surfactant-polymer technology economically recovers 15% to 25% OOIP more oil than waterflooding in the swept pore space of an oil reservoir. However, alkaline-surfactant-polymer technology is not amenable to the naturally fractured reservoirs or those with thief zones because much of the injected solution bypasses the target pore space containing oil. The objective of this work is to investigate whether combining these two technologies could broaden the applicability of alkaline-surfactant-polymer flooding into these reservoirs. Fluid-fluid interaction with different gel chemical compositions and alkaline-surfactant-polymer solution with pH values ranging from 9.2 to 12.9 have been tested. Aluminum-polyacrylamide gels are not stable to alkaline-surfactant-polymer solutions at any pH. Chromium--polyacrylamide gels with polymer to chromium ion ratios of 25 or greater were stable to alkaline-surfactant-polymer solutions if solution pH was 10.6 or less. When the polymer to chromium ion was 15 or less, chromium-polyacrylamide gels were stable to alkaline-surfactant-polymer solutions with pH values up to 12.9. Chromium-xanthan gum gels were stable to alkaline-surfactant-polymer solutions with pH values of 12.9 at the polymer to chromium ion ratios tested. Silicate-polyacrylamide, resorcinol-formaldehyde, and sulfomethylated resorcinol-formaldehyde gels were also stable to alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Iron-polyacrylamide gels were immediately destroyed when contacted with any of the alkaline-surfactant-polymer solutions with pH values of 9.2 to 12.9.

  11. Mechanical and Swelling Properties of Poly (vinyl alcohol) and Hyaluronic Acid Gels used in Biomaterial Systems - a Comparative Study

    OpenAIRE

    Jagadeeshwar Kodavaty; Abhijit P. Deshpande

    2014-01-01

    There is an increasing demand for designing controlled drug delivery systems with materials which are morebiocompatible, economical and materials which can be processed easily. Poly (vinyl alcohol) (PVA) and hyaluronicacid (HA) are promising polymers for applications in drug delivery. PVA forms gel based on the acetal bridges when cross linked with glutaraldehyde (GA). On the other hand, HA a natural polymer, forms gel with divinyl sulfone(DVS) as a crosslinker. PVA and HA blends upon crossli...

  12. Staining Proteins in Gels

    OpenAIRE

    Gallagher, Sean; Chakavarti, Deb

    2008-01-01

    Following separation by electrophoretic methods, proteins in a gel can be detected by several staining methods. This unit describes protocols for detecting proteins by four popular methods. Coomassie blue staining is an easy and rapid method. Silver staining, while more time consuming, is considerably more sensitive and can thus be used to detect smaller amounts of protein. Fluorescent staining is a popular alternative to traditional staining procedures, mainly because it is more sensitive th...

  13. MAGIC Gel Dosimetry

    Science.gov (United States)

    Mifflin, Rachel; Shahnazi, Kambiz; Jesseph, Rick

    2008-10-01

    Proton therapy has proven a very successful tool in treating certain tumors, but a three dimensional view of this fact has not yet been clearly demonstrated. In this experiment we have used MAGIC (Methacrylic and Ascorbic Acid in Gelatin Initiated by Copper) gel to represent brain tissue and gone through normal treatment planning for an Acoustic Neuroma to show the three dimensional dose distributions associated with such a tumor.

  14. Performance of Ion-gel Actuator Containing Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    H.Kokubo; Y.Kato; T.Honda; M.Watanabe

    2007-01-01

    1 Results Electroactive polymers (EAPs) driven by transducing electric energy into mechanical energy have been the subjects of recent interest[1]."Ionic liquids",consisting entirely of cation and anion,have characteristic features such as negligible volatility,non-flammability,thermal and chemical stability,and high ionic conductivity.We proposed an EAP actuator utilizing ion-gels[2-3],which consist of ionic liquids and polymers,sandwiching with two carbon material sheets as shown in Fig.1.This electrol...

  15. Polymer Chemistry

    Science.gov (United States)

    Williams, Martha; Roberson, Luke; Caraccio, Anne

    2010-01-01

    This viewgraph presentation describes new technologies in polymer and material chemistry that benefits NASA programs and missions. The topics include: 1) What are Polymers?; 2) History of Polymer Chemistry; 3) Composites/Materials Development at KSC; 4) Why Wiring; 5) Next Generation Wiring Materials; 6) Wire System Materials and Integration; 7) Self-Healing Wire Repair; 8) Smart Wiring Summary; 9) Fire and Polymers; 10) Aerogel Technology; 11) Aerogel Composites; 12) Aerogels for Oil Remediation; 13) KSC's Solution; 14) Chemochromic Hydrogen Sensors; 15) STS-130 and 131 Operations; 16) HyperPigment; 17) Antimicrobial Materials; 18) Conductive Inks Formulations for Multiple Applications; and 19) Testing and Processing Equipment.

  16. Responsive gelation of hydrophobized linear polymer

    DEFF Research Database (Denmark)

    Madsen, Claus Greve; Toeth, Joachim; Jørgensen, Lene;

    In this study we present the rheological properties of a physically linked polymer network, composed of linear hydrophilic chains, modified with hydrophobic moieties in each end. Solutions of the polymer in ethanol-water mixtures showed Newtonian behaviour up to about 99 % ethanol, with the highest...... viscosity observed in a 1:1 mixture of ethanol and water. In pure ethanol, the polymer forms a thermo-responsive, non-Newtonian gel, which collapses upon addition of as little as 1 % water or heating to about 40 °C....

  17. FORMULATION AND EVALUATION OF FLOATING IN SITU GEL BASED GASTRO RETENTIVE DRUG DELIVERY OF CIMETIDINE

    Directory of Open Access Journals (Sweden)

    Bhargav D. Jayswal

    2012-05-01

    Full Text Available The present investigation deals with the formulation and evaluation of sodium alginate and pectin basedIn situ gel of Cimetidine. Sodium alginate and pectin were used as a polymer and CaCO3 was used as across-linking agent. In-situ forming polymeric formulations drug delivery systems is in sol form beforeadministration in the body, but once administered, undergoes gelation in-situ to form a gel. Theformulation of gel depends upon factors like temperature modulation, pH changes, presence of ions andultra-violet irradiation, from which drug gets released in sustained and controlled manner. The objectiveof this study was to develop a novel in- situ gel system for sustained drug delivery using naturalbiodegradable polymers. The system utilizes polymers that exhibit sol-to-gel phase transition due tochange in specific physico-chemical parameters. In-situ gel was formed at a biological pH. In vitrorelease studies were conducted in simulated gastric fluid and cumulative amount of drug release wasanalyzed by spectrophotometry. From designed set of experiments, it was evident that formulationcontaining 1.2% of sodium alginate and 1.5% of pectin control the release of drug for longer duration.The in-situ gel exhibited the expected, viscosity, drug content, pH, in vitro gelling capacity, in vitrofloating ability, water uptake ability and sustained drug release.The drug release from the in situ gelsfollows the fickian diffusion type of release.

  18. Host Tissue Interaction, Fate, and Risks of Degradable and Nondegradable Gel Fillers

    DEFF Research Database (Denmark)

    Christensen, Lise

    2009-01-01

    with particulated fillers, polyacrylamide gel and silicone oil. However, these complications differ in nature and depend on the filler type used. METHODS AND MATERIALS This overview presents the different gel filler types, how they interact with host tissue, and what can go wrong. The results and conclusion......-bindings to the polymer in order to obtain a more dense molecular structure, which will prolong degradation and filling effect of the gel. Other gel fillers contain particles of organic (poly-lactic acid) or inorganic (calcium hydroxylapatite) material, which have been used in human tissue for other purposes (degradable...... suture material and bone cement, respectively). The permanent fillers (silicone oil and polyacrylamide gel) have been used for many years, silicone mainly in the US and polyacrylamide gel in most countries outside the US and Canada. OBJECTIVE Complications occur, and they appear to be more frequent...

  19. The Synthesis of a Novel Cellulose Physical Gel

    Directory of Open Access Journals (Sweden)

    Jiufang Duan

    2014-01-01

    Full Text Available Cellulose possessing β-cyclodextrin (β-CD was used as a host molecule and cellulose possessing ferrocene (Fc as a guest polymer. Infrared spectra, differential scanning calorimetry (DSC, ultraviolet spectroscopy (UV, and contact angle analysis were used to characterise the material structure and the inclusion behaviour. The results showed that the β-CD-cellulose and the Fc-cellulose can form inclusion complexes. Moreover, ferrocene oxidation, and reduction of state can be adjusted by sodium hypochlorite (NaClO as an oxidant and glutathione (GSH as a reductant. In this study, a physical gel based on β-CD-cellulose/Fc-cellulose was formed under mild conditions in which autonomous healing between cut surfaces occurred after 24 hours. The physical gel can be controlled in the sol-gel transition. The compressive strength of the Fc-cellulose/β-CD-cellulose gel increased with increased cellulose concentration. The host-guest interaction between the side chains of cellulose could strengthen the gel. The cellulose physical gel may eventually be used as a stimulus-responsive, healing material in biomedical applications.

  20. Cyclodextrin-polyhydrazine degradable gels for hydrophobic drug delivery.

    Science.gov (United States)

    Jalalvandi, Esmat; Cabral, Jaydee; Hanton, Lyall R; Moratti, Stephen C

    2016-12-01

    An injectable and biocompatible hydrogel system was designed for hydrophobic drug delivery. This hydrogel consisted of degradable polymers with cyclodextrin (CD) moieties. CD groups were used to increase the solubility of a hydrophobic molecule (nicardipine) in an aqueous solution through the formation of the inclusion complex. Two sets of gels were prepared by mixing oxidized dextran (DA) and CD functionalized polyhydrazine (PH) at physiological conditions and different level of crosslinking via hydrazone bonds. Cytotoxicity studies on the gels and their components confirmed the biocompatibility of these materials. Gel-30 with higher crosslinking density showed a two week degradation period whereas this period was 10days for gel-10, with lower crosslinking density, to complete degradation. The results from swelling tests and rheological measurements were also found to be dependent on crosslinking density of the hydrogels. Release profile of the hydrogel displayed a sustained release of nicardipin up to 6days for gel-30 and a 4day release with initial burst release for gel-10. PMID:27612699

  1. Hybrid Polymer-Network Hydrogels with Tunable Mechanical Response

    Directory of Open Access Journals (Sweden)

    Sebastian Czarnecki

    2016-03-01

    Full Text Available Hybrid polymer-network gels built by both physical and covalent polymer crosslinking combine the advantages of both these crosslinking types: they exhibit high mechanical strength along with excellent fracture toughness and extensibility. If these materials are extensively deformed, their physical crosslinks can break such that strain energy is dissipated and irreversible fracturing is restricted to high strain only. This mechanism of energy dissipation is determined by the kinetics and thermodynamics of the physical crosslinking contribution. In this paper, we present a poly(ethylene glycol (PEG based material toolkit to control these contributions in a rational and custom fashion. We form well-defined covalent polymer-network gels with regularly distributed additional supramolecular mechanical fuse links, whose strength of connectivity can be tuned without affecting the primary polymer-network composition. This is possible because the supramolecular fuse links are based on terpyridine–metal complexation, such that the mere choice of the fuse-linking metal ion adjusts their kinetics and thermodynamics of complexation–decomplexation, which directly affects the mechanical properties of the hybrid gels. We use oscillatory shear rheology to demonstrate this rational control and enhancement of the mechanical properties of the hybrid gels. In addition, static light scattering reveals their highly regular and well-defined polymer-network structures. As a result of both, the present approach provides an easy and reliable concept for preparing hybrid polymer-network gels with rationally designed properties.

  2. Drug-eluting stents with biodegradable polymer for the treatment of patients with diabetes mellitus: clinical outcome at 2 years in a large population of patients

    Directory of Open Access Journals (Sweden)

    Wiemer M

    2015-02-01

    Full Text Available Marcus Wiemer,1 Gian Battista Danzi,2 Nick West,3 Vassilios Voudris,4 René Koning,5 Stefan Hoffmann,6 Mario Lombardi,7 Josepa Mauri,8 Rade Babic,9 Fraser Witherow10On behalf of the NOBORI 2 Investigators 1Department of Cardiology, Heart and Diabetes Center North Rhine–Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany; 2Ospedale Maggiore Policlinico, Milan, Italy; 3Papworth Hospital, Cambridge, UK; 4Onassis Cardiac Surgery Center, Athens, Greece; 5Clinique Saint Hilaire, Rouen, France; 6Vivantes Netzwerk für Gesundheit GmbH, Berlin, Germany; 7Azienda Ospedaliera Villa Sofia, Palermo, Italy; 8Hospital Universitari Germans Trias i Pujol, Badalona, Spain; 9Institute for Cardiovascular Diseases Dedinje, Belgrade, Serbia; 10Dorset County Hospital, Dorchester, UK Objective: This study investigates the safety and efficacy of a third-generation drug-eluting stent (DES with biodegradable polymer in the complex patient population of diabetes mellitus (DM. Clinical trial registration: ISRCTN81649913. Background: Percutaneous coronary interventions in patients with DM are associated with a higher incidence of death, restenosis, and stent thrombosis as compared to non-diabetic patients. The use of a DES has been shown to improve outcomes in diabetic patients. Methods: Out of 3,067 patients, enrolled in 126 centers worldwide in the NOBORI 2 registry, 888 patients suffered from DM, 213 of them (14% being insulin-dependent DM (IDDM. Two years’ follow-up has been completed in this study. Results: At 1- and 2-year follow-up, 97% and 95% of the patients, respectively, were available. The reported target lesion failure (TLF rates at 1- and 2-year follow-up were 6.0% and 7.2% in the DM group, respectively, and 3.0% and 4.2% in the non-DM group, respectively (P<0.001 for both years. Inside the DM group, the TLF rates of 9.9% and 11.7% at the 1- and 2-year follow-ups, respectively, in patients with IDDM were significantly higher than the TLF rates of 4

  3. Field-Theoretic Studies of Nanostructured Triblock Polyelectrolyte Gels

    Science.gov (United States)

    Audus, Debra; Fredrickson, Glenn

    2012-02-01

    Recently, experimentalists have developed nanostructured, reversible gels formed from triblock polyelectrolytes (Hunt et al. 2011, Lemmers et al. 2010, 2011). These gels have fascinating and tunable properties that reflect a heterogeneous morphology with domains on the order of tens of nanometers. The complex coacervate domains, aggregated oppositely charged end-blocks, are embedded in a continuous aqueous matrix and are bridged by uncharged, hydrophilic polymer mid-blocks. We report on simulation studies that employ statistical field theory models of triblock polyelectrolytes, and we explore the equilibrium self-assembly of these remarkable systems. As the charge complexation responsible for the formation of coacervate domains is driven by electrostatic correlations, we have found it necessary to pursue full ``field-theoretic simulations'' of the models, as opposed to the familiar self-consistent field theory approach. Our investigations have focused on morphological trends with mid- and end-block lengths, polymer concentration, salt concentration and charge density.

  4. Structural and Electrochemical Analysis of PMMA Based Gel Electrolyte Membranes

    Directory of Open Access Journals (Sweden)

    Chithra M. Mathew

    2015-01-01

    Full Text Available New gel polymer electrolytes containing poly(vinylidene chloride-co-acrylonitrile and poly(methyl methacrylate are prepared by solution casting method. With the addition of 60 wt.% of EC to PVdC-AN/PMMA blend, ionic conductivity value 0.398×10-6 S cm−1 has been achieved. XRD and FT-IR studies have been conducted to investigate the structure and complexation in the polymer gel electrolytes. The FT-IR spectra show that the functional groups C=O and C≡N play major role in ion conduction. Thermal stability of the prepared membranes is found to be about 180°C.

  5. Measurement of Dynamic Light Scattering Intensity in Gels

    CERN Document Server

    Rochas, Cyrille

    2015-01-01

    In the scientific literature little attention has been given to the use of dynamic light scattering (DLS) as a tool for extracting the thermodynamic information contained in the absolute intensity of light scattered by gels. In this article we show that DLS yields reliable measurements of the intensity of light scattered by the thermodynamic fluctuations, not only in aqueous polymer solutions, but also in hydrogels. In hydrogels, light scattered by osmotic fluctuations is heterodyned by that from static or slowly varying inhomogeneities. The two components are separable owing to their different time scales, giving good experimental agreement with macroscopic measurements of the osmotic pressure. DLS measurements in gels are, however, tributary to depolarised light scattering from the network as well as to multiple light scattering. The paper examines these effects, as well as the instrumental corrections required to determine the osmotic modulus. For guest polymers trapped in a hydrogel the measured intensity...

  6. Bistable electroactive polymers (BSEP): large-strain actuation of rigid polymers

    Science.gov (United States)

    Yu, Zhibin; Niu, Xiaofan; Brochu, Paul; Yuan, Wei; Li, Huafeng; Chen, Bin; Pei, Qibing

    2010-04-01

    Reversible, large-strain, bistable actuation has been a lasting puzzle in the pursuit of smart materials and structures. Conducting polymers are bistable, but the achievable strain is small. Large deformations have been achieved in dielectric elastomers at the expense of mechanical strength. The gel or gel-like soft polymers generally have elastic moduli around or less than 10 MPa. The deformed polymer relaxes to its original shape once the applied electric field is removed. We report new, bistable electroactive polymers (BSEP) that are capable of electrically actuated strains as high as 335% area strain. The BSEP could be useful for constructing rigid structures. The structures can support high mechanical loads, and be actuated to large-strain deformations. We will present one unique application of the BSEP for Braille displays that can be quickly refreshed and maintain the displayed contents without a bias voltage.

  7. pH-sensitive methacrylic copolymer gels and the production thereof

    Science.gov (United States)

    Mallapragada, Surya K.; Anderson, Brian C.

    2007-05-15

    The present invention provides novel gel forming methacrylic blocking copolymers that exhibit cationic pH-sensitive behavior as well as good water solubility. The copolymers are constructed by polymerization of a tertiary amine methacrylate with either a (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) polymer, such as the commercially available Pluronic.RTM. polymers, or a poly(ethylene glycol)methyl ether polymer. The polymers may be used for drug and gene delivery, protein separation, as structural supplements, and more.

  8. Clinical Analysis of Gel Dressing in the Treatment of Diabetic Foot Ulcer%凝胶敷料用于糖尿病足溃疡的疗效观察

    Institute of Scientific and Technical Information of China (English)

    陆艳; 黄伟英

    2014-01-01

    目的:观察凝胶敷料(微赛恩凝胶)用于糖尿病足溃疡的疗效。方法将100例糖尿病足患者随机分为观察组50例用凝胶敷料喷涂;对照组50例常规治疗不予凝胶敷料喷涂.比较两组治疗效果。结果观察组疗效优于对照组(P<0.01)。结论凝胶敷料治疗糖尿病足溃疡疗效显著。%Objective To observe the gel dressing (micro scion gel) for treatment of diabetic foot ulcer. Methods 100 cases of diabetic foot were randomly divided into the observation group of 50 cases with gel dressing spray; 50 cases in the control group conventional treatment not gel dressing spray. The treatment ef ect of the two groups were compared. Results The observation group was bet er than control group (P<0.01). Conclusion Gel dressing on the treatment of diabetic foot ulcer is significantly.

  9. Multicomponent Thermodynamics of Strain-Induced Polymer Crystallization.

    Science.gov (United States)

    Zha, Liyun; Wu, Yixian; Hu, Wenbing

    2016-07-14

    We developed a linear combination of two Flory's melting-point theories, one for stretched and the other for solution polymers, to predict the melting point of stretched solution polymers. The dependences of the melting strains on varying temperatures, polymer volume fractions, and solvent qualities were verified by the onset strains of crystallization in our dynamic Monte Carlo simulations of stretched solution polymers under a constant strain rate. In addition, owing to phase separation before crystallization in a poor solvent, calibration of polymer concentration to the polymer-rich phase appears necessary for the verification. Our results set up a preliminary thermodynamic background for the investigation of the multicomponent effect on strain-induced crystallization of polymers in rubbers and gels as well as on shear-induced crystallization of polymers in solutions and blends. PMID:27337066

  10. Stability of the response and dependence of the optical signal as function of dose rate of the alanine gel dosimeter for electron clinic beams; Estabilidade da resposta e dependencia do sinal optico em funcao da taxa de dose do dosimetro alanina gel para feixes clinicos de eletrons

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cleber Feijo; Dias, Daniel Menezes; Campos, Leticia Lucente, E-mail: cfsilva@ipen.b, E-mail: dmdias@ipen.b, E-mail: lcrodri@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    This work evaluates the stability of response and the dependence on the optical response of dose rate of the alanine gel solution developed at the IPEN, Sao Paulo, Brazil, for possible future usage as 3D dosemeter in the medical area, as the area is lack of measure instrumentation for three dimension dose

  11. Inorganic-organic composites by sol-gel techniques

    OpenAIRE

    Schmidt, Helmut K.

    1990-01-01

    The sol-gel process opens the possibility of combining inorganic and organic units to new hybrid polymers. Organic units can be used for structural modification of the inorganic backbone, for creating new functions within an inorganic network and for building up organic polymeric chains. The materials show interesting perspectives with respect to structural (surface hardness, strength) and functional properties (e.g. diffusion, photocuring, incorporation of dyes, optical properties). A review...

  12. Implementation of MRI gel dosimetry in radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Baeck, S.Aa.J

    1998-12-01

    Gel dosimetry was used together with magnetic resonance imaging (MRI) to measure three-dimensional absorbed dose distributions in radiation therapy. Two different dosimeters were studied: ferrous- and monomer gel, based on the principles of radiation-induced oxidation and polymerisation, respectively. Single clinical electron and photon beams were evaluated and gel dose distributions were mainly within 2% of conventional detector results. The ferrous-gel was also used for clinical proton beams. A decrease in signal per absorbed dose was found close to the end of the range of the protons (15-20%). This effect was explained as a linear energy transfer dependence, further supported with Monte Carlo simulations. A method for analysing and comparing data from treatment planning system (TPS) and gel measurements was developed. The method enables a new pixel by pixel evaluation, isodose comparison and dose volume histogram verification. Two standard clinical radiation therapy procedures were examined using the developed TPS verification method. The treatment regimes included several beams of different radiation qualities. The TPS calculated data were in very good agreement with the dose distribution measured by the ferrous-gel. However, in a beam abutment region, larger dose difference was found. Beam adjustment errors and a minor TPS underestimation of the lateral scatter contribution outside the primary electron beam may explain the discrepancy. The overall uncertainty in the ferrous-gel dose determination was considerably reduced using an optimised MRI acquisition protocol and a new MRI scanner. The relative dose uncertainty was found to be better than 3.3% for all dose levels (95% confidence level). Using the method developed for comparing measured gel data with calculated treatment plans, the gel dosimetry method was proven to be a useful tool for radiation treatment planning verification 103 refs, 20 figs, 6 tabs

  13. Nanostructured assemblies from amphiphilic ABC multiblock polymers

    Science.gov (United States)

    Hillmyer, Marc A.

    2012-02-01

    Amphiphilic AB diblock copolymers containing a water compatible segment can self-assemble in aqueous media to give supramolecular structures that include simple spherical micelles and macromolecular vesicles termed polymersomes. Amphiphilic ABA triblocks with hydrophobic end blocks can adopt analogous structures but can also form gels at high polymer concentrations. The structural and chemical diversity demonstrated in block copolymer micelles and gels makes them attractive for applications ranging from drug delivery to personal care products to nanoreactors. The inclusion of a third block in amphiphilic ABC triblock systems can lead to a much wider array of self-assembled structures that depend not only on composition but also on block sequence, architecture and incompatibility considerations. I will present our recent efforts on tuning micelle and gel structure and behavior using controlled architecture ABC triblocks. The combination of diverse polymer segments into a single macromolecule is a powerful method for development of self-assembled structures with both new form and new function.

  14. Polymers & People

    Science.gov (United States)

    Lentz, Linda; Robinson, Thomas; Martin, Elizabeth; Miller, Mary; Ashburn, Norma

    2004-01-01

    Each Tuesday during the fall of 2002, teams of high school students from three South Carolina counties conducted a four-hour polymer institute for their peers. In less than two months, over 300 students visited the Charleston County Public Library in Charleston, South Carolina, to explore DNA, nylon, rubber, gluep, and other polymers. Teams of…

  15. Polymer Informatics

    Science.gov (United States)

    Adams, Nico

    Polymers are arguably the most important set of materials in common use. The increasing adoption of both combinatorial as well as high-throughput approaches, coupled with an increasing amount of interdisciplinarity, has wrought tremendous change in the field of polymer science. Yet the informatics tools required to support and further enhance these changes are almost completely absent. In the first part of the chapter, a critical analysis of the challenges facing modern polymer informatics is provided. It is argued, that most of the problems facing the field today are rooted in the current scholarly communication process and the way in which chemists and polymer scientists handle and publish data. Furthermore, the chapter reviews existing modes of representing and communicating polymer information and discusses the impact, which the emergence of semantic technologies will have on the way in which scientific and polymer data is published and transmitted. In the second part, a review of the use of informatics tools for the prediction of polymer properties and in silico design of polymers is offered.

  16. The preparation and performance of a temperature resistant polymer/fly-ash plugging gel%高温聚合物/粉煤灰凝胶封窜体系的制备及性能赖南君1,2,李志豪1,王勇3,周宁1,刘艳勤1

    Institute of Scientific and Technical Information of China (English)

    赖南君; 李志豪; 王勇; 周宁; 刘艳勤

    2015-01-01

    以耐温磺化聚合物( SPAM)、水溶性酚醛树脂、粉煤灰制备了适合于YT油田的高温封窜调堵剂。正交实验优选得到:0.3%SPAM、0.04%交联剂、5%粉煤灰的体系。温度、pH、矿化度对成胶效果的影响结果表明,100℃或更高温度对凝胶成胶不利;pH=5时,成胶效果最好;矿化度增加不利于成胶,但当矿化度是50000 mg/L左右时,成胶黏度仍接近45000 mPa· s。耐温性测试结果表明,110℃高温老化20 d后,体系黏度有所降低,但体系仍能保证不脱水;热滚实验表明,凝胶的温度使用上限是150℃。岩心实验表明体系能够明显提高注气压力,减缓注气压降。%To block the gas channeling of high-temperature YT oilfield ,a gel plugging agent which is made up of sulfonated polymer (SPAM),water-soluble phenolic resin and ash had been prepared .The tests results of 0.3%SPAM,0.04%crosslinkers,5%fly-ash system and the temperature ,pH,and salinity influence on gelling show that:100℃and higher temperature is unfavorable on the gelation;the gelling is better when pH=5;Increased salinity is not conducive to gelling ,but when salinity is 50 000 mg/L or so,the gel viscos-ity is still close to 45 000 mPa· s.The results of temperature resistance showed that after 110℃high tem-perature aging 20 d,the gel viscosity decreased ,but the system is still no water separation;Hot rolling ex-periments showed that the upper temperature limit of the gel is 150 ℃.The core experience show that the gel can significantly improve the injection pressure and slow down the decrease of injection pressure .

  17. Metal-containing radiation-sensitive polymers

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A.Y.

    1986-01-01

    The copolymers of methyl methacrylate with alkali metal salts (Na, K, and Cs) of methacrylic acid have been prepared by saponification K, and Cs) of methylacrylic acid have been prepared by saponification of the homopolymer poly(methyl methacrylate), PMMA. Low degrees of hydrolysis have been achieved by a heterogeneous system, and from the infrared spectra it has been confirmed that the ester groups of the methyl methacrylates are directly converted to the metal salts of methacrylic acid. These ionomers exhibit pseudo high molecular weights in gel permeation chromatogram, but no appreciable increase in intrinsic viscosities is observed in comparison to PMMA. The coordinated inorganic polymers poly((dithio-2,2'-diacetato)bis(dimethylsulfoxide)dioxouranium(VI)) and poly()methylenebis(thio)-2,2'-bis(acetato))bis(dimethylsulfoxide)dioxouranium(VI))have been synthesized in dimethyl sulfoxide solution with about 90% yield. The degree of polymerization and the number of average molecular weights of these polymers have been assessed by high resolution nuclear magnetic resonance, with which the acetato end group to the bridging ligand group ratios have been determined. The polymers bridging ligand group ratios have been determined. The polymers have been characterized by employing various techniques: infrared spectra, thermal gravimetric analysis, /sup 13/C solid state nuclear magnetic resonance, and gel permeation chromatography. The prepared polymer samples have been subjected to various doses of /sup 137/Cs gamma radiation under which the polymers predominantly undergo chain scission. The radiation sensitivities of the polymers are assessed by G values which are obtained from gel permeation chromatograms. These uranyl polymers exhibit unusually high G values.

  18. Modeling Cryotherapy Ice Ball Dimensions and Isotherms in a Novel Gel-based Model to Determine Optimal Cryo-needle Configurations and Settings for Potential Use in Clinical Practice

    Science.gov (United States)

    Shah, Taimur T.; Arbel, Uri; Foss, Sonja; Zachman, Andrew; Rodney, Simon; Ahmed, Hashim U.; Arya, Manit

    2016-01-01

    Objective To gain a better understanding of ice ball dimensions and temperature isotherms relevant for cell kill when using combinations of cryo-needles we set out to answer 4 questions: (1) what type of cryo-needle? (2) how many needles? (3) best spatial configuration? and (4) correct duty cycle percentage? Methods We conducted laboratory experiments to monitor ice ball dimensions and create multi-needle planar isotherm maps for 17G and 10G cryo-needles using a novel multi-needle thermocouple fixture within gel at body temperature. We tested configurations of 1-4 cryo-needles at duty cycles of 20%-100% with 1-2.5 cm spacing. Results Analysis of various combinations shows that a central core of ≤−40°C develops at a distance of ~1 cm around the cryo-needles. Temperature increases linearly from this point to the ice ball leading edge (0°C), which is a further ≈1 cm away. Thus, the −40°C isotherm is approximately 1 cm inside the leading edge of the ice ball. The optimum distance between cryo-needles was 1.5-2 cm, at duty cycle settings of 70%-100%. At distances further apart or with lower duty cycle settings, ice balls either had a central core >−40°C or had an hourglass shape. Conclusion In answer to questions 1-3, tumor length, diameter, and shape will ultimately determine the number of needles and their configuration. However, we propose a conservative distance for cryo-needle placement between 1 and 1.5 cm should be adopted for clinical practice. In answer to question 4, using low duty cycle settings runs the risk of incomplete −40°C isotherm coverage of the tumor, and thus in routine practice we suggest that settings of 70%-100% are most appropriate. PMID:26902833

  19. The effect of large deformation and material nonlinearity on gel indentation

    Institute of Scientific and Technical Information of China (English)

    Zheng Duan; Yonghao An; Jiaping Zhang; Hanqing Jiang

    2012-01-01

    A gel,an aggregate of polymers with solvents,has dual attributes of solid and liquid as solvent migrates in and out of the polymer network.Indentation has recently been used to characterize the mechanical properties of gels.This paper evaluates the effects of large deformation and material nonlinearity on gel indentation through theoretical modeling and finite element analysis.It is found that large deformation significantly affects the interpretation of the experimental observations and the classical relation between indentation force and depth has limitations for large deformation.The material nonlinearity does not play a very important role on indentation experiment so that the poroelasticity is a good approximation.Based on these observations,this paper proposes an alternative approach to measure the mechanical properties of gels,namely,uniaxial compression experiment.

  20. A finite element method for transient analysis of concurrent large deformation and mass transport in gels

    Science.gov (United States)

    Zhang, Jiaping; Zhao, Xuanhe; Suo, Zhigang; Jiang, Hanqing

    2009-05-01

    A gel is an aggregate of polymers and solvent molecules. The polymers crosslink into a three-dimensional network by strong chemical bonds and enable the gel to retain its shape after a large deformation. The solvent molecules, however, interact among themselves and with the network by weak physical bonds and enable the gel to be a conduit of mass transport. The time-dependent concurrent process of large deformation and mass transport is studied by developing a finite element method. We combine the kinematics of large deformation, the conservation of the solvent molecules, the conditions of local equilibrium, and the kinetics of migration to evolve simultaneously two fields: the displacement of the network and the chemical potential of the solvent. The finite element method is demonstrated by analyzing several phenomena, such as swelling, draining and buckling. This work builds a platform to study diverse phenomena in gels with spatial and temporal complexity.

  1. DSC and conductivity studies on PVA based proton conducting gel electrolytes

    Indian Academy of Sciences (India)

    S L Agrawal; Arvind Awadhia

    2004-12-01

    An attempt has been made in the present work to prepare polyvinyl alcohol (PVA) based proton conducting gel electrolytes in ammonium thiocyanate (NH4SCN) solution and characterize them. DSC studies affirm the formation of gels along with the presence of partial complexes. The cole–cole plots exhibit maximum ionic conductivity (2.58 × 10-3 S cm-1) for gel samples containing 6 wt% of PVA. The conductivity of gel electrolytes exhibit liquid like nature at low polymer concentrations while the behaviour is seen to be affected by the formation of PVA–NH4SCN complexes upon increase in polymer content beyond 5 wt%. Temperature dependence of ionic conductivity exhibits VTF behaviour.

  2. Smart viscoelastic and self-healing characteristics of graphene nano-gels

    CERN Document Server

    Dhar, Purbarun; Maganti, Lakshmi Sirisha

    2016-01-01

    Readily synthesizable nano-graphene and poly ethylene glycol based stable gels have been synthesized employing an easy refluxing method and exhaustive rheological and viscoelastic characterizations have been performed to understand the nature of such complex gel systems. The gels exhibit shear thinning response with pronounced yield stress values which is indicative of a microstructure where the graphene nanoflakes intercalate with the polymer chains and form a pseudo spring damper network. Experimentations on the thixotropic behavior of the gels indicate that the presence of the G nanoflakes leads to immensely augmented structural stability capable of withstanding severe impact shears. Further information about the localized interactions of the G nanoflakes with the polymer chains is revealed from the amplitude and frequency sweep analyses in both linear and nonlinear viscoelastic regimes. Massively enhanced cross over amplitude values are recorded and several smart effects such as enhanced elastic behavior ...

  3. Coupling the Alkaline-Surfactant-Polymer Technology and The Gelation Technology to Maximize Oil Production

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm Pitts; Jie Qi; Dan Wilson; Phil Dowling; David Stewart; Bill Jones

    2005-12-01

    Performance and produced polymer evaluation of four alkaline-surfactant-polymer projects concluded that only one of the projects could have benefited from combining the alkaline-surfactant-polymer and gelation technologies. Cambridge, the 1993 Daqing, Mellott Ranch, and the Wardlaw alkaline-surfacant-polymer floods were studied. An initial gel treatment followed by an alkaline-surfactant-polymer flood in the Wardlaw field would have been a benefit due to reduction of fracture flow. Numerical simulation demonstrated that reducing the permeability of a high permeability zone of a reservoir with gel improved both waterflood and alkaline-surfactant-polymer flood oil recovery. A Minnelusa reservoir with both A and B sand production was simulated. A and B sands are separated by a shale layer. A sand and B sand waterflood oil recovery was improved by 196,000 bbls or 3.3% OOIP when a gel was placed in the B sand. Alkaline-surfactant-polymer flood oil recovery improvement over a waterflood was 392,000 bbls or 6.5% OOIP. Placing a gel into the B sand prior to an alkaline-surfactant-polymer flood resulted in 989,000 bbl or 16.4% OOIP more oil than only water injection. A sand and B sand alkaline-surfactant-polymer flood oil recovery was improved by 596,000 bbls or 9.9% OOIP when a gel was placed in the B sand.

  4. Dihydroxybenzene/benzoquinone-containing polymers: organic redox polymers

    Energy Technology Data Exchange (ETDEWEB)

    Moulay, S. [Universite de Blida, Lab. de Chimie-Physique Macromoleculaire, Institut de Chimie Industrielle (Algeria)

    2000-08-01

    Polymers containing hydroquinone, catechol or their corresponding benzoquinones are a special class of redox polymers. Three pathways of their syntheses are possible: condensation polymerization of suitable monomers, addition polymerization of vinyl monomers containing redox moiety, and chemical attachment of redox unit onto pre-made polymeric matrix. A range of functionalized matrices have been employed such as polyethers, polyesters, polycarbonates, polyurethanes, polyamides and others. Protection of their phenolic functionality has conducted to chemically interesting redox polymer precursors. The presence of a redox moiety coupled with the extant functionalization of the polymer matrix makes the materials very valuable, of wide properties and consequently of vast applicability. For instance, in the oil field, some polymers such as carboxy-methyl-cellulose (CMC) are often applied as to bring about a viscosity improvement and therefore to facilitate the oil drilling. In this regard, Patel evaluated sulfo-alkylated polymeric catechol, namely sulfo-methylated and sulfo-ethylated resins. Indeed, polymeric catechol chemically modified as such exhibited a marked ability to control the viscosity, the gel strength, as well as the filtrate loss of aqueous oil drilling fluids.

  5. Sol-gel processing : an alternative way to glasses for optoelectronics

    OpenAIRE

    Roggendorf, Hans; Schmidt, Helmut K.

    1989-01-01

    The sol-gel route to glass offers considerable advantages. Among these the control of composition, low processing temperatures, organical modifications of inorganic polymers leading to a new a class of glass-like materials, the processing of sols to coatings or powders, and the possibilities to structurize glasses are interesting for optoelectronic glasses. Future perspectives of sol-gel processing of optoelectronic glasses as well as some experimental results concerning the state of the art ...

  6. Random and block copolymerization in metal oxide gel synthesis from metalorganic compounds

    Science.gov (United States)

    Mukherjee, S. P.

    1985-01-01

    The introduction and development of the block copolymerization concept in metal oxide gel synthesis will in the future generate a new class of glass/microcrystalline materials. By the year 2004, better scientific understanding of the chemical principles controlling the distribution of network formers or modifiers in silicate gels will permit the synthesis of architecturally well-defined block polymers with unique high-performance behavior.

  7. THE PROPERTIES OF CARRAGEENAN GELS

    Directory of Open Access Journals (Sweden)

    Grubnik I.M., Gladukh Ye.V., Chernyaev S.V.

    2012-04-01

    Full Text Available The article presents the results of studies on the functional properties of carrageenan, depending on the concentration of sodium chloride and xanthan in gels. It is established that the main factors in the syneresis of carrageenan gels are its concentration, the presence of ions and gums in solution. If using sodium chloride there is a change in the structure of mesh of the resulting gel, which leads to an increase in syneresis.

  8. Capillary fracture of soft gels

    OpenAIRE

    Bostwick, Joshua B.; Daniels, Karen E.

    2013-01-01

    A liquid droplet resting on a soft gel substrate can deform that substrate to the point of material failure, whereby fractures develop on the gel surface that propagate outwards from the contact-line in a starburst pattern. In this paper, we characterize i) the initiation process in which the number of arms in the starburst is controlled by the ratio of surface tension contrast to the gel's elastic modulus and ii) the propagation dynamics showing that once fractures are initiated they propaga...

  9. 微柱凝胶技术检测血型不规则抗体的临床应用%The clinical application of irregular antibody screening by microtube gel technology

    Institute of Scientific and Technical Information of China (English)

    宁芳; 粟明丽; 邓梅英

    2014-01-01

    目的:分析微柱凝胶技术对输血患者进行血型不规则抗体的筛查情况及临床应用。方法对2010年1月~2013年12月于桂林医学院附属医院输血患者29208例进行不规则抗体检测,统计分析阳性结果,鉴定阳性抗体的特异性。结果29208例患者中,检出不规则抗体阳性者90例,阳性率为0.31%。特异性抗体以Rh血型系统居多,抗-D抗体占2.22%、抗-E抗体占21.11%、抗-Ec抗体占11.11%;MNSs系统抗-Mur抗体11例(12.22%)、抗-M抗体7例(7.78%);Lewis系统抗-Lea抗体占8.89%;冷抗体占7.78%。非特异性抗体占13.33%。结论输血前对患者血液进行血型不规则抗体筛查并鉴定其特异性,输注不含相应抗原的血液,避免溶血性输血反应的发生,对确保输血安全有效有重要的临床意义。%Objective To analyze the situation and clinical application of microtube gel technology (MGT) in the irreg-ular antibody screening of patients before blood transfusion. Methods 29 208 patients from January 2010 to December 2013 in Affiliated Hospital of Guilin Medical University were screened for irregular antibody. The results were statisti-cal analyzed to identify the specificity of positive antibody. Results Among 29 208 patients, there were 90 cases with irregular antibody, the positive rate was 0.31%. Rh blood type system accounted for the most part of the specific anti-bodies: 2.22% for anti-D antibody, 21.11% of anti-E antibody and 11.11% of anti-Ec antibody. 11 cases of Anti-Mur of MNSs system accounted for 12.22% of the total and 7 cases of anti-M antibody accounted for 7.78%. 8.89% was for Anti-Lea antibody in Lewis system and 7.78% for cold antibody. And the non-specific antibodies accounted for 13.33%. Conclusion Irregular antibody should be screened and its specificity should also be identified before transfu-sion. To transfuse the blood without the corresponding antibodies can prevent transfusional hemolytic reaction, which is

  10. Electrochemistry of polyamidoamine dendrimers ester gel electrolytes

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong; MO Zunli

    2004-01-01

    This paper described the first example of polyamidoamine dendrimers ester (PAMAM) used as a gel electrolyte with a short-chain polyethylene glycol (MPEG-400) as a plasticizer. The polymer films are solid and sticky. Background cyclic voltammetry (CV) shows a potential window between +0.7 and -0.7 V vs. Ag/AgCl. The voltammetry of ferrocene and 7,7,8,8-tetracyanoquinodimethane (TCNQ) indicates that diffusion coefficients are in the range of 10-a-10-9 cm2/s.Ionic conductivities are approximately 10-6 S/cm. Similar films using dimethyl sulfoxide (DMSO) as a plasticizer instead of MPEG-400 have demonstrated ionic conductivities of 10-4 S/cra and reversible voltammetry. However, UV spectrophotometry shows that 70% of the DMSO is lost under vacuum, indicating the difficulty in quantifying the DMSO content when exposed to vacuum.

  11. Transdermal Iontophoretic Delivery of Atenolol in Combination with Penetration Enhancers: Optimization and Evaluation on Solution and Gels

    Directory of Open Access Journals (Sweden)

    Nandy B. C.

    2009-07-01

    Full Text Available In the present investigation, we prepared Atenolol (1.5 % w/w solution and various polymer formulations by incorporating the tween-20 or L-menthol, as a penetration enhancers and its effect on permeation of the drug through the excised abdominal rat skin were used to examined by using the vertical Franz-type diffusion cell. The physicochemical interactions between Atenolol and various polymers were investigated by performing the assay, ultra violet absorption maxima, Fourier transform infrared spectroscopy and it was further confirmed by thin layer chromatography studies, from which drug did not show any evidence of interaction with the polymers. We found that, L-menthol was superior than tween-20 to iontophoresis [current density applied 0.5 mA/cm2 and 90:10 (on: off ratio], in enhancing the transdermal permeation of Atenolol; it enhanced the flux of Atenolol by more than 2-folds, comparison to the preparations without penetration enhancer via passive diffusion, and 3 folds increased using iontophoresis alone with a shorter lag time. Atenolol also showed good stability in gel formulations. The basic parameters like % loading dose released at the end of the study, permeation coefficient and steady state flux (Jss were calculated and showed statistically significant difference (p<0.05. The results indicated that suitable iontophoretic delivery with desired permeability could be appeared and the cumulative amount-time curves were suitable to fit by a zero order equations which indicated a steady state permeation rate or sustained effect could be achieved from hydrogel; when it is combined with penetration enhancer, L-menthol. The results demonstrate that the semisolid gel formulations are more applicable than solution as a transdermal iontophoretic delivery system to administer clinically. Electrically assisted transdermal delivery of Atenolol significantly increased transport compared to passive delivery. Also, rapid and modulated delivery was

  12. Coupling the Alkaline-Surfactant-Polymer Technology and the Gelation Technology to Maximize Oil Production

    Energy Technology Data Exchange (ETDEWEB)

    Malcolm Pitts; Jie Qi; Dan Wilson; Phil Dowling; David Stewart; Bill Jones

    2005-12-01

    Gelation technologies have been developed to provide more efficient vertical sweep efficiencies for flooding naturally fractured oil reservoirs or reservoirs with different sand lenses with high permeability contrast. The field proven alkaline-surfactant-polymer technology economically recovers 15% to 25% OOIP more crude oil than waterflooding froin swept pore space of an oil reservoir. However, alkaline-surfactant-polymer technology is not amenable to naturally fractured reservoirs or reservoirs with high permeability contrast zones because much of injected solution bypasses target pore space containing oil. This work investigates whether combining these two technologies could broaden applicability of alkaline-surfactant-polymer flooding into these reservoirs. Fluid-fluid interaction with different gel chemical compositions and alkaline-surfactant-polymer solution with pH values ranging from 9.2 to 12.9 have been tested. Aluminum-polyacrylamide gels are not stable to alkaline-surfactant-polymer solutions at any pH. Chromium-polyacrylamide gels with polymer to chromium ion ratios of 25 or greater were stable to alkaline-surfactant-polymer solutions if solution pH was 10.6 or less. When the polymer to chromium ion was 15 or less, chromium-polyacrylamide gels were stable to alkaline-surfactant-polymer solutions with pH values up to 12.9. Chromium-xanthan gum gels were stable to alkaline-surfactant-polymer solutions with pH values of 12.9 at the polymer to chromium ion ratios tested. Silicate-polyacrylamide, resorcinol-formaldehyde, and sulfomethylated resorcinol-formaldehyde gels were also stable to alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Iron-polyacrylamide gels were immediately destroyed when contacted with any of the alkaline-surfactant-polymer solutions with pH values ranging from 9.2 to 12.9. Gel solutions under dynamic conditions of linear corefloods showed similar stability to alkaline-surfactant-polymer solutions as in

  13. A novel insight into membrane fouling mechanism regarding gel layer filtration: Flory-Huggins based filtration mechanism.